]> git.karo-electronics.de Git - linux-beck.git/commitdiff
serial: 8250: Split base port operations from universal driver
authorPeter Hurley <peter@hurleysoftware.com>
Sat, 27 Jun 2015 13:19:00 +0000 (09:19 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 24 Jul 2015 00:43:01 +0000 (17:43 -0700)
Refactor base port operations into new file; 8250_port.c.

Legacy irq handling, RSA port support, port storage for universal
driver, driver definition, module parameters and linkage remain in
8250_core.c

The source file split and resulting modules is diagrammed below:

  8250_core.c ====>   8250_core.c __
              \                     \
               \                     +-- 8250.ko (alias 8250_core)
                \     8250_pnp.c  __/     (universal driver)
                 \
                  =>  8250_port.c __
                                    \
                                     +-- 8250_base.ko
                      8250_dma.c  __/     (port operations)

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/8250/8250.h
drivers/tty/serial/8250/8250_core.c
drivers/tty/serial/8250/8250_port.c [new file with mode: 0644]
drivers/tty/serial/8250/Makefile
include/linux/serial_8250.h

index c43f74c53cd98259056400cc86b9ff355c4993ca..dd233108ec07ab6f454400f11740400fbf4f53b5 100644 (file)
@@ -211,3 +211,14 @@ static inline int ns16550a_goto_highspeed(struct uart_8250_port *up)
        }
        return 1;
 }
+
+static inline int serial_index(struct uart_port *port)
+{
+       return port->minor - 64;
+}
+
+#if 0
+#define DEBUG_INTR(fmt...)     printk(fmt)
+#else
+#define DEBUG_INTR(fmt...)     do { } while (0)
+#endif
index 37fff12dd4d06b9f561eeabfe2c22f1cb4aa88e4..cfbb9d728e317fae55daa324ab5d8f780cb023f0 100644 (file)
@@ -1,25 +1,23 @@
 /*
- *  Driver for 8250/16550-type serial ports
+ *  Universal/legacy driver for 8250/16550-type serial ports
  *
  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
  *
  *  Copyright (C) 2001 Russell King.
  *
+ *  Supports: ISA-compatible 8250/16550 ports
+ *           PNP 8250/16550 ports
+ *           early_serial_setup() ports
+ *           userspace-configurable "phantom" ports
+ *           "serial8250" platform devices
+ *           serial8250_register_8250_port() ports
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
- *
- * A note about mapbase / membase
- *
- *  mapbase is the physical address of the IO port.
- *  membase is an 'ioremapped' cookie.
  */
 
-#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
-#define SUPPORT_SYSRQ
-#endif
-
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/ioport.h>
@@ -58,33 +56,10 @@ static unsigned int nr_uarts = CONFIG_SERIAL_8250_RUNTIME_UARTS;
 
 static struct uart_driver serial8250_reg;
 
-static int serial_index(struct uart_port *port)
-{
-       return port->minor - 64;
-}
-
 static unsigned int skip_txen_test; /* force skip of txen test at init time */
 
-/*
- * Debugging.
- */
-#if 0
-#define DEBUG_AUTOCONF(fmt...) printk(fmt)
-#else
-#define DEBUG_AUTOCONF(fmt...) do { } while (0)
-#endif
-
-#if 0
-#define DEBUG_INTR(fmt...)     printk(fmt)
-#else
-#define DEBUG_INTR(fmt...)     do { } while (0)
-#endif
-
 #define PASS_LIMIT     512
 
-#define BOTH_EMPTY     (UART_LSR_TEMT | UART_LSR_THRE)
-
-
 #include <asm/serial.h>
 /*
  * SERIAL_PORT_DFNS tells us about built-in ports that have no
@@ -120,2695 +95,268 @@ static struct hlist_head irq_lists[NR_IRQ_HASH];
 static DEFINE_MUTEX(hash_mutex);       /* Used to walk the hash */
 
 /*
- * Here we define the default xmit fifo size used for each type of UART.
+ * This is the serial driver's interrupt routine.
+ *
+ * Arjan thinks the old way was overly complex, so it got simplified.
+ * Alan disagrees, saying that need the complexity to handle the weird
+ * nature of ISA shared interrupts.  (This is a special exception.)
+ *
+ * In order to handle ISA shared interrupts properly, we need to check
+ * that all ports have been serviced, and therefore the ISA interrupt
+ * line has been de-asserted.
+ *
+ * This means we need to loop through all ports. checking that they
+ * don't have an interrupt pending.
  */
-static const struct serial8250_config uart_config[] = {
-       [PORT_UNKNOWN] = {
-               .name           = "unknown",
-               .fifo_size      = 1,
-               .tx_loadsz      = 1,
-       },
-       [PORT_8250] = {
-               .name           = "8250",
-               .fifo_size      = 1,
-               .tx_loadsz      = 1,
-       },
-       [PORT_16450] = {
-               .name           = "16450",
-               .fifo_size      = 1,
-               .tx_loadsz      = 1,
-       },
-       [PORT_16550] = {
-               .name           = "16550",
-               .fifo_size      = 1,
-               .tx_loadsz      = 1,
-       },
-       [PORT_16550A] = {
-               .name           = "16550A",
-               .fifo_size      = 16,
-               .tx_loadsz      = 16,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .rxtrig_bytes   = {1, 4, 8, 14},
-               .flags          = UART_CAP_FIFO,
-       },
-       [PORT_CIRRUS] = {
-               .name           = "Cirrus",
-               .fifo_size      = 1,
-               .tx_loadsz      = 1,
-       },
-       [PORT_16650] = {
-               .name           = "ST16650",
-               .fifo_size      = 1,
-               .tx_loadsz      = 1,
-               .flags          = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
-       },
-       [PORT_16650V2] = {
-               .name           = "ST16650V2",
-               .fifo_size      = 32,
-               .tx_loadsz      = 16,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
-                                 UART_FCR_T_TRIG_00,
-               .rxtrig_bytes   = {8, 16, 24, 28},
-               .flags          = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
-       },
-       [PORT_16750] = {
-               .name           = "TI16750",
-               .fifo_size      = 64,
-               .tx_loadsz      = 64,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
-                                 UART_FCR7_64BYTE,
-               .rxtrig_bytes   = {1, 16, 32, 56},
-               .flags          = UART_CAP_FIFO | UART_CAP_SLEEP | UART_CAP_AFE,
-       },
-       [PORT_STARTECH] = {
-               .name           = "Startech",
-               .fifo_size      = 1,
-               .tx_loadsz      = 1,
-       },
-       [PORT_16C950] = {
-               .name           = "16C950/954",
-               .fifo_size      = 128,
-               .tx_loadsz      = 128,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               /* UART_CAP_EFR breaks billionon CF bluetooth card. */
-               .flags          = UART_CAP_FIFO | UART_CAP_SLEEP,
-       },
-       [PORT_16654] = {
-               .name           = "ST16654",
-               .fifo_size      = 64,
-               .tx_loadsz      = 32,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
-                                 UART_FCR_T_TRIG_10,
-               .rxtrig_bytes   = {8, 16, 56, 60},
-               .flags          = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
-       },
-       [PORT_16850] = {
-               .name           = "XR16850",
-               .fifo_size      = 128,
-               .tx_loadsz      = 128,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .flags          = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
-       },
-       [PORT_RSA] = {
-               .name           = "RSA",
-               .fifo_size      = 2048,
-               .tx_loadsz      = 2048,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11,
-               .flags          = UART_CAP_FIFO,
-       },
-       [PORT_NS16550A] = {
-               .name           = "NS16550A",
-               .fifo_size      = 16,
-               .tx_loadsz      = 16,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .flags          = UART_CAP_FIFO | UART_NATSEMI,
-       },
-       [PORT_XSCALE] = {
-               .name           = "XScale",
-               .fifo_size      = 32,
-               .tx_loadsz      = 32,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .flags          = UART_CAP_FIFO | UART_CAP_UUE | UART_CAP_RTOIE,
-       },
-       [PORT_OCTEON] = {
-               .name           = "OCTEON",
-               .fifo_size      = 64,
-               .tx_loadsz      = 64,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .flags          = UART_CAP_FIFO,
-       },
-       [PORT_AR7] = {
-               .name           = "AR7",
-               .fifo_size      = 16,
-               .tx_loadsz      = 16,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00,
-               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
-       },
-       [PORT_U6_16550A] = {
-               .name           = "U6_16550A",
-               .fifo_size      = 64,
-               .tx_loadsz      = 64,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
-       },
-       [PORT_TEGRA] = {
-               .name           = "Tegra",
-               .fifo_size      = 32,
-               .tx_loadsz      = 8,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
-                                 UART_FCR_T_TRIG_01,
-               .rxtrig_bytes   = {1, 4, 8, 14},
-               .flags          = UART_CAP_FIFO | UART_CAP_RTOIE,
-       },
-       [PORT_XR17D15X] = {
-               .name           = "XR17D15X",
-               .fifo_size      = 64,
-               .tx_loadsz      = 64,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .flags          = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
-                                 UART_CAP_SLEEP,
-       },
-       [PORT_XR17V35X] = {
-               .name           = "XR17V35X",
-               .fifo_size      = 256,
-               .tx_loadsz      = 256,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11 |
-                                 UART_FCR_T_TRIG_11,
-               .flags          = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
-                                 UART_CAP_SLEEP,
-       },
-       [PORT_LPC3220] = {
-               .name           = "LPC3220",
-               .fifo_size      = 64,
-               .tx_loadsz      = 32,
-               .fcr            = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
-                                 UART_FCR_R_TRIG_00 | UART_FCR_T_TRIG_00,
-               .flags          = UART_CAP_FIFO,
-       },
-       [PORT_BRCM_TRUMANAGE] = {
-               .name           = "TruManage",
-               .fifo_size      = 1,
-               .tx_loadsz      = 1024,
-               .flags          = UART_CAP_HFIFO,
-       },
-       [PORT_8250_CIR] = {
-               .name           = "CIR port"
-       },
-       [PORT_ALTR_16550_F32] = {
-               .name           = "Altera 16550 FIFO32",
-               .fifo_size      = 32,
-               .tx_loadsz      = 32,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
-       },
-       [PORT_ALTR_16550_F64] = {
-               .name           = "Altera 16550 FIFO64",
-               .fifo_size      = 64,
-               .tx_loadsz      = 64,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
-       },
-       [PORT_ALTR_16550_F128] = {
-               .name           = "Altera 16550 FIFO128",
-               .fifo_size      = 128,
-               .tx_loadsz      = 128,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
-               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
-       },
-/* tx_loadsz is set to 63-bytes instead of 64-bytes to implement
-workaround of errata A-008006 which states that tx_loadsz should  be
-configured less than Maximum supported fifo bytes */
-       [PORT_16550A_FSL64] = {
-               .name           = "16550A_FSL64",
-               .fifo_size      = 64,
-               .tx_loadsz      = 63,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
-                                 UART_FCR7_64BYTE,
-               .flags          = UART_CAP_FIFO,
-       },
-};
-
-/* Uart divisor latch read */
-static int default_serial_dl_read(struct uart_8250_port *up)
-{
-       return serial_in(up, UART_DLL) | serial_in(up, UART_DLM) << 8;
-}
-
-/* Uart divisor latch write */
-static void default_serial_dl_write(struct uart_8250_port *up, int value)
-{
-       serial_out(up, UART_DLL, value & 0xff);
-       serial_out(up, UART_DLM, value >> 8 & 0xff);
-}
-
-#if defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_SERIAL_8250_RT288X)
-
-/* Au1x00/RT288x UART hardware has a weird register layout */
-static const s8 au_io_in_map[8] = {
-        0,     /* UART_RX  */
-        2,     /* UART_IER */
-        3,     /* UART_IIR */
-        5,     /* UART_LCR */
-        6,     /* UART_MCR */
-        7,     /* UART_LSR */
-        8,     /* UART_MSR */
-       -1,     /* UART_SCR (unmapped) */
-};
-
-static const s8 au_io_out_map[8] = {
-        1,     /* UART_TX  */
-        2,     /* UART_IER */
-        4,     /* UART_FCR */
-        5,     /* UART_LCR */
-        6,     /* UART_MCR */
-       -1,     /* UART_LSR (unmapped) */
-       -1,     /* UART_MSR (unmapped) */
-       -1,     /* UART_SCR (unmapped) */
-};
-
-static unsigned int au_serial_in(struct uart_port *p, int offset)
-{
-       if (offset >= ARRAY_SIZE(au_io_in_map))
-               return UINT_MAX;
-       offset = au_io_in_map[offset];
-       if (offset < 0)
-               return UINT_MAX;
-       return __raw_readl(p->membase + (offset << p->regshift));
-}
-
-static void au_serial_out(struct uart_port *p, int offset, int value)
-{
-       if (offset >= ARRAY_SIZE(au_io_out_map))
-               return;
-       offset = au_io_out_map[offset];
-       if (offset < 0)
-               return;
-       __raw_writel(value, p->membase + (offset << p->regshift));
-}
-
-/* Au1x00 haven't got a standard divisor latch */
-static int au_serial_dl_read(struct uart_8250_port *up)
+static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
 {
-       return __raw_readl(up->port.membase + 0x28);
-}
+       struct irq_info *i = dev_id;
+       struct list_head *l, *end = NULL;
+       int pass_counter = 0, handled = 0;
 
-static void au_serial_dl_write(struct uart_8250_port *up, int value)
-{
-       __raw_writel(value, up->port.membase + 0x28);
-}
+       DEBUG_INTR("serial8250_interrupt(%d)...", irq);
 
-#endif
+       spin_lock(&i->lock);
 
-static unsigned int hub6_serial_in(struct uart_port *p, int offset)
-{
-       offset = offset << p->regshift;
-       outb(p->hub6 - 1 + offset, p->iobase);
-       return inb(p->iobase + 1);
-}
+       l = i->head;
+       do {
+               struct uart_8250_port *up;
+               struct uart_port *port;
 
-static void hub6_serial_out(struct uart_port *p, int offset, int value)
-{
-       offset = offset << p->regshift;
-       outb(p->hub6 - 1 + offset, p->iobase);
-       outb(value, p->iobase + 1);
-}
+               up = list_entry(l, struct uart_8250_port, list);
+               port = &up->port;
 
-static unsigned int mem_serial_in(struct uart_port *p, int offset)
-{
-       offset = offset << p->regshift;
-       return readb(p->membase + offset);
-}
+               if (port->handle_irq(port)) {
+                       handled = 1;
+                       end = NULL;
+               } else if (end == NULL)
+                       end = l;
 
-static void mem_serial_out(struct uart_port *p, int offset, int value)
-{
-       offset = offset << p->regshift;
-       writeb(value, p->membase + offset);
-}
+               l = l->next;
 
-static void mem32_serial_out(struct uart_port *p, int offset, int value)
-{
-       offset = offset << p->regshift;
-       writel(value, p->membase + offset);
-}
+               if (l == i->head && pass_counter++ > PASS_LIMIT) {
+                       /* If we hit this, we're dead. */
+                       printk_ratelimited(KERN_ERR
+                               "serial8250: too much work for irq%d\n", irq);
+                       break;
+               }
+       } while (l != end);
 
-static unsigned int mem32_serial_in(struct uart_port *p, int offset)
-{
-       offset = offset << p->regshift;
-       return readl(p->membase + offset);
-}
+       spin_unlock(&i->lock);
 
-static void mem32be_serial_out(struct uart_port *p, int offset, int value)
-{
-       offset = offset << p->regshift;
-       iowrite32be(value, p->membase + offset);
-}
+       DEBUG_INTR("end.\n");
 
-static unsigned int mem32be_serial_in(struct uart_port *p, int offset)
-{
-       offset = offset << p->regshift;
-       return ioread32be(p->membase + offset);
+       return IRQ_RETVAL(handled);
 }
 
-static unsigned int io_serial_in(struct uart_port *p, int offset)
+/*
+ * To support ISA shared interrupts, we need to have one interrupt
+ * handler that ensures that the IRQ line has been deasserted
+ * before returning.  Failing to do this will result in the IRQ
+ * line being stuck active, and, since ISA irqs are edge triggered,
+ * no more IRQs will be seen.
+ */
+static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
 {
-       offset = offset << p->regshift;
-       return inb(p->iobase + offset);
-}
+       spin_lock_irq(&i->lock);
 
-static void io_serial_out(struct uart_port *p, int offset, int value)
-{
-       offset = offset << p->regshift;
-       outb(value, p->iobase + offset);
+       if (!list_empty(i->head)) {
+               if (i->head == &up->list)
+                       i->head = i->head->next;
+               list_del(&up->list);
+       } else {
+               BUG_ON(i->head != &up->list);
+               i->head = NULL;
+       }
+       spin_unlock_irq(&i->lock);
+       /* List empty so throw away the hash node */
+       if (i->head == NULL) {
+               hlist_del(&i->node);
+               kfree(i);
+       }
 }
 
-static int serial8250_default_handle_irq(struct uart_port *port);
-static int exar_handle_irq(struct uart_port *port);
-
-static void set_io_from_upio(struct uart_port *p)
+static int serial_link_irq_chain(struct uart_8250_port *up)
 {
-       struct uart_8250_port *up = up_to_u8250p(p);
-
-       up->dl_read = default_serial_dl_read;
-       up->dl_write = default_serial_dl_write;
+       struct hlist_head *h;
+       struct hlist_node *n;
+       struct irq_info *i;
+       int ret, irq_flags = up->port.flags & UPF_SHARE_IRQ ? IRQF_SHARED : 0;
 
-       switch (p->iotype) {
-       case UPIO_HUB6:
-               p->serial_in = hub6_serial_in;
-               p->serial_out = hub6_serial_out;
-               break;
+       mutex_lock(&hash_mutex);
 
-       case UPIO_MEM:
-               p->serial_in = mem_serial_in;
-               p->serial_out = mem_serial_out;
-               break;
+       h = &irq_lists[up->port.irq % NR_IRQ_HASH];
 
-       case UPIO_MEM32:
-               p->serial_in = mem32_serial_in;
-               p->serial_out = mem32_serial_out;
-               break;
+       hlist_for_each(n, h) {
+               i = hlist_entry(n, struct irq_info, node);
+               if (i->irq == up->port.irq)
+                       break;
+       }
 
-       case UPIO_MEM32BE:
-               p->serial_in = mem32be_serial_in;
-               p->serial_out = mem32be_serial_out;
-               break;
+       if (n == NULL) {
+               i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
+               if (i == NULL) {
+                       mutex_unlock(&hash_mutex);
+                       return -ENOMEM;
+               }
+               spin_lock_init(&i->lock);
+               i->irq = up->port.irq;
+               hlist_add_head(&i->node, h);
+       }
+       mutex_unlock(&hash_mutex);
 
-#if defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_SERIAL_8250_RT288X)
-       case UPIO_AU:
-               p->serial_in = au_serial_in;
-               p->serial_out = au_serial_out;
-               up->dl_read = au_serial_dl_read;
-               up->dl_write = au_serial_dl_write;
-               break;
-#endif
+       spin_lock_irq(&i->lock);
 
-       default:
-               p->serial_in = io_serial_in;
-               p->serial_out = io_serial_out;
-               break;
-       }
-       /* Remember loaded iotype */
-       up->cur_iotype = p->iotype;
-       p->handle_irq = serial8250_default_handle_irq;
-}
+       if (i->head) {
+               list_add(&up->list, i->head);
+               spin_unlock_irq(&i->lock);
 
-static void
-serial_port_out_sync(struct uart_port *p, int offset, int value)
-{
-       switch (p->iotype) {
-       case UPIO_MEM:
-       case UPIO_MEM32:
-       case UPIO_MEM32BE:
-       case UPIO_AU:
-               p->serial_out(p, offset, value);
-               p->serial_in(p, UART_LCR);      /* safe, no side-effects */
-               break;
-       default:
-               p->serial_out(p, offset, value);
+               ret = 0;
+       } else {
+               INIT_LIST_HEAD(&up->list);
+               i->head = &up->list;
+               spin_unlock_irq(&i->lock);
+               irq_flags |= up->port.irqflags;
+               ret = request_irq(up->port.irq, serial8250_interrupt,
+                                 irq_flags, "serial", i);
+               if (ret < 0)
+                       serial_do_unlink(i, up);
        }
-}
 
-/*
- * For the 16C950
- */
-static void serial_icr_write(struct uart_8250_port *up, int offset, int value)
-{
-       serial_out(up, UART_SCR, offset);
-       serial_out(up, UART_ICR, value);
+       return ret;
 }
 
-static unsigned int serial_icr_read(struct uart_8250_port *up, int offset)
+static void serial_unlink_irq_chain(struct uart_8250_port *up)
 {
-       unsigned int value;
+       /*
+        * yes, some broken gcc emit "warning: 'i' may be used uninitialized"
+        * but no, we are not going to take a patch that assigns NULL below.
+        */
+       struct irq_info *i;
+       struct hlist_node *n;
+       struct hlist_head *h;
 
-       serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD);
-       serial_out(up, UART_SCR, offset);
-       value = serial_in(up, UART_ICR);
-       serial_icr_write(up, UART_ACR, up->acr);
+       mutex_lock(&hash_mutex);
 
-       return value;
-}
+       h = &irq_lists[up->port.irq % NR_IRQ_HASH];
 
-/*
- * FIFO support.
- */
-static void serial8250_clear_fifos(struct uart_8250_port *p)
-{
-       if (p->capabilities & UART_CAP_FIFO) {
-               serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO);
-               serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO |
-                              UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
-               serial_out(p, UART_FCR, 0);
+       hlist_for_each(n, h) {
+               i = hlist_entry(n, struct irq_info, node);
+               if (i->irq == up->port.irq)
+                       break;
        }
-}
 
-void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p)
-{
-       serial8250_clear_fifos(p);
-       serial_out(p, UART_FCR, p->fcr);
-}
-EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos);
+       BUG_ON(n == NULL);
+       BUG_ON(i->head == NULL);
 
-void serial8250_rpm_get(struct uart_8250_port *p)
-{
-       if (!(p->capabilities & UART_CAP_RPM))
-               return;
-       pm_runtime_get_sync(p->port.dev);
-}
-EXPORT_SYMBOL_GPL(serial8250_rpm_get);
+       if (list_empty(i->head))
+               free_irq(up->port.irq, i);
 
-void serial8250_rpm_put(struct uart_8250_port *p)
-{
-       if (!(p->capabilities & UART_CAP_RPM))
-               return;
-       pm_runtime_mark_last_busy(p->port.dev);
-       pm_runtime_put_autosuspend(p->port.dev);
+       serial_do_unlink(i, up);
+       mutex_unlock(&hash_mutex);
 }
-EXPORT_SYMBOL_GPL(serial8250_rpm_put);
 
 /*
- * These two wrappers ensure that enable_runtime_pm_tx() can be called more than
- * once and disable_runtime_pm_tx() will still disable RPM because the fifo is
- * empty and the HW can idle again.
+ * This function is used to handle ports that do not have an
+ * interrupt.  This doesn't work very well for 16450's, but gives
+ * barely passable results for a 16550A.  (Although at the expense
+ * of much CPU overhead).
  */
-static void serial8250_rpm_get_tx(struct uart_8250_port *p)
+static void serial8250_timeout(unsigned long data)
 {
-       unsigned char rpm_active;
-
-       if (!(p->capabilities & UART_CAP_RPM))
-               return;
+       struct uart_8250_port *up = (struct uart_8250_port *)data;
 
-       rpm_active = xchg(&p->rpm_tx_active, 1);
-       if (rpm_active)
-               return;
-       pm_runtime_get_sync(p->port.dev);
+       up->port.handle_irq(&up->port);
+       mod_timer(&up->timer, jiffies + uart_poll_timeout(&up->port));
 }
 
-static void serial8250_rpm_put_tx(struct uart_8250_port *p)
+static void serial8250_backup_timeout(unsigned long data)
 {
-       unsigned char rpm_active;
+       struct uart_8250_port *up = (struct uart_8250_port *)data;
+       unsigned int iir, ier = 0, lsr;
+       unsigned long flags;
 
-       if (!(p->capabilities & UART_CAP_RPM))
-               return;
-
-       rpm_active = xchg(&p->rpm_tx_active, 0);
-       if (!rpm_active)
-               return;
-       pm_runtime_mark_last_busy(p->port.dev);
-       pm_runtime_put_autosuspend(p->port.dev);
-}
-
-/*
- * IER sleep support.  UARTs which have EFRs need the "extended
- * capability" bit enabled.  Note that on XR16C850s, we need to
- * reset LCR to write to IER.
- */
-static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
-{
-       unsigned char lcr = 0, efr = 0;
-       /*
-        * Exar UARTs have a SLEEP register that enables or disables
-        * each UART to enter sleep mode separately.  On the XR17V35x the
-        * register is accessible to each UART at the UART_EXAR_SLEEP
-        * offset but the UART channel may only write to the corresponding
-        * bit.
-        */
-       serial8250_rpm_get(p);
-       if ((p->port.type == PORT_XR17V35X) ||
-          (p->port.type == PORT_XR17D15X)) {
-               serial_out(p, UART_EXAR_SLEEP, sleep ? 0xff : 0);
-               goto out;
-       }
-
-       if (p->capabilities & UART_CAP_SLEEP) {
-               if (p->capabilities & UART_CAP_EFR) {
-                       lcr = serial_in(p, UART_LCR);
-                       efr = serial_in(p, UART_EFR);
-                       serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
-                       serial_out(p, UART_EFR, UART_EFR_ECB);
-                       serial_out(p, UART_LCR, 0);
-               }
-               serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
-               if (p->capabilities & UART_CAP_EFR) {
-                       serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
-                       serial_out(p, UART_EFR, efr);
-                       serial_out(p, UART_LCR, lcr);
-               }
-       }
-out:
-       serial8250_rpm_put(p);
-}
-
-#ifdef CONFIG_SERIAL_8250_RSA
-/*
- * Attempts to turn on the RSA FIFO.  Returns zero on failure.
- * We set the port uart clock rate if we succeed.
- */
-static int __enable_rsa(struct uart_8250_port *up)
-{
-       unsigned char mode;
-       int result;
-
-       mode = serial_in(up, UART_RSA_MSR);
-       result = mode & UART_RSA_MSR_FIFO;
-
-       if (!result) {
-               serial_out(up, UART_RSA_MSR, mode | UART_RSA_MSR_FIFO);
-               mode = serial_in(up, UART_RSA_MSR);
-               result = mode & UART_RSA_MSR_FIFO;
-       }
-
-       if (result)
-               up->port.uartclk = SERIAL_RSA_BAUD_BASE * 16;
-
-       return result;
-}
-
-static void enable_rsa(struct uart_8250_port *up)
-{
-       if (up->port.type == PORT_RSA) {
-               if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
-                       spin_lock_irq(&up->port.lock);
-                       __enable_rsa(up);
-                       spin_unlock_irq(&up->port.lock);
-               }
-               if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
-                       serial_out(up, UART_RSA_FRR, 0);
-       }
-}
-
-/*
- * Attempts to turn off the RSA FIFO.  Returns zero on failure.
- * It is unknown why interrupts were disabled in here.  However,
- * the caller is expected to preserve this behaviour by grabbing
- * the spinlock before calling this function.
- */
-static void disable_rsa(struct uart_8250_port *up)
-{
-       unsigned char mode;
-       int result;
-
-       if (up->port.type == PORT_RSA &&
-           up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) {
-               spin_lock_irq(&up->port.lock);
-
-               mode = serial_in(up, UART_RSA_MSR);
-               result = !(mode & UART_RSA_MSR_FIFO);
-
-               if (!result) {
-                       serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
-                       mode = serial_in(up, UART_RSA_MSR);
-                       result = !(mode & UART_RSA_MSR_FIFO);
-               }
-
-               if (result)
-                       up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
-               spin_unlock_irq(&up->port.lock);
-       }
-}
-#endif /* CONFIG_SERIAL_8250_RSA */
-
-/*
- * This is a quickie test to see how big the FIFO is.
- * It doesn't work at all the time, more's the pity.
- */
-static int size_fifo(struct uart_8250_port *up)
-{
-       unsigned char old_fcr, old_mcr, old_lcr;
-       unsigned short old_dl;
-       int count;
-
-       old_lcr = serial_in(up, UART_LCR);
-       serial_out(up, UART_LCR, 0);
-       old_fcr = serial_in(up, UART_FCR);
-       old_mcr = serial_in(up, UART_MCR);
-       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
-                   UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
-       serial_out(up, UART_MCR, UART_MCR_LOOP);
-       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
-       old_dl = serial_dl_read(up);
-       serial_dl_write(up, 0x0001);
-       serial_out(up, UART_LCR, 0x03);
-       for (count = 0; count < 256; count++)
-               serial_out(up, UART_TX, count);
-       mdelay(20);/* FIXME - schedule_timeout */
-       for (count = 0; (serial_in(up, UART_LSR) & UART_LSR_DR) &&
-            (count < 256); count++)
-               serial_in(up, UART_RX);
-       serial_out(up, UART_FCR, old_fcr);
-       serial_out(up, UART_MCR, old_mcr);
-       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
-       serial_dl_write(up, old_dl);
-       serial_out(up, UART_LCR, old_lcr);
-
-       return count;
-}
-
-/*
- * Read UART ID using the divisor method - set DLL and DLM to zero
- * and the revision will be in DLL and device type in DLM.  We
- * preserve the device state across this.
- */
-static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
-{
-       unsigned char old_dll, old_dlm, old_lcr;
-       unsigned int id;
-
-       old_lcr = serial_in(p, UART_LCR);
-       serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
-
-       old_dll = serial_in(p, UART_DLL);
-       old_dlm = serial_in(p, UART_DLM);
-
-       serial_out(p, UART_DLL, 0);
-       serial_out(p, UART_DLM, 0);
-
-       id = serial_in(p, UART_DLL) | serial_in(p, UART_DLM) << 8;
-
-       serial_out(p, UART_DLL, old_dll);
-       serial_out(p, UART_DLM, old_dlm);
-       serial_out(p, UART_LCR, old_lcr);
-
-       return id;
-}
-
-/*
- * This is a helper routine to autodetect StarTech/Exar/Oxsemi UART's.
- * When this function is called we know it is at least a StarTech
- * 16650 V2, but it might be one of several StarTech UARTs, or one of
- * its clones.  (We treat the broken original StarTech 16650 V1 as a
- * 16550, and why not?  Startech doesn't seem to even acknowledge its
- * existence.)
- *
- * What evil have men's minds wrought...
- */
-static void autoconfig_has_efr(struct uart_8250_port *up)
-{
-       unsigned int id1, id2, id3, rev;
-
-       /*
-        * Everything with an EFR has SLEEP
-        */
-       up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
-
-       /*
-        * First we check to see if it's an Oxford Semiconductor UART.
-        *
-        * If we have to do this here because some non-National
-        * Semiconductor clone chips lock up if you try writing to the
-        * LSR register (which serial_icr_read does)
-        */
-
-       /*
-        * Check for Oxford Semiconductor 16C950.
-        *
-        * EFR [4] must be set else this test fails.
-        *
-        * This shouldn't be necessary, but Mike Hudson (Exoray@isys.ca)
-        * claims that it's needed for 952 dual UART's (which are not
-        * recommended for new designs).
-        */
-       up->acr = 0;
-       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
-       serial_out(up, UART_EFR, UART_EFR_ECB);
-       serial_out(up, UART_LCR, 0x00);
-       id1 = serial_icr_read(up, UART_ID1);
-       id2 = serial_icr_read(up, UART_ID2);
-       id3 = serial_icr_read(up, UART_ID3);
-       rev = serial_icr_read(up, UART_REV);
-
-       DEBUG_AUTOCONF("950id=%02x:%02x:%02x:%02x ", id1, id2, id3, rev);
-
-       if (id1 == 0x16 && id2 == 0xC9 &&
-           (id3 == 0x50 || id3 == 0x52 || id3 == 0x54)) {
-               up->port.type = PORT_16C950;
-
-               /*
-                * Enable work around for the Oxford Semiconductor 952 rev B
-                * chip which causes it to seriously miscalculate baud rates
-                * when DLL is 0.
-                */
-               if (id3 == 0x52 && rev == 0x01)
-                       up->bugs |= UART_BUG_QUOT;
-               return;
-       }
-
-       /*
-        * We check for a XR16C850 by setting DLL and DLM to 0, and then
-        * reading back DLL and DLM.  The chip type depends on the DLM
-        * value read back:
-        *  0x10 - XR16C850 and the DLL contains the chip revision.
-        *  0x12 - XR16C2850.
-        *  0x14 - XR16C854.
-        */
-       id1 = autoconfig_read_divisor_id(up);
-       DEBUG_AUTOCONF("850id=%04x ", id1);
-
-       id2 = id1 >> 8;
-       if (id2 == 0x10 || id2 == 0x12 || id2 == 0x14) {
-               up->port.type = PORT_16850;
-               return;
-       }
-
-       /*
-        * It wasn't an XR16C850.
-        *
-        * We distinguish between the '654 and the '650 by counting
-        * how many bytes are in the FIFO.  I'm using this for now,
-        * since that's the technique that was sent to me in the
-        * serial driver update, but I'm not convinced this works.
-        * I've had problems doing this in the past.  -TYT
-        */
-       if (size_fifo(up) == 64)
-               up->port.type = PORT_16654;
-       else
-               up->port.type = PORT_16650V2;
-}
-
-/*
- * We detected a chip without a FIFO.  Only two fall into
- * this category - the original 8250 and the 16450.  The
- * 16450 has a scratch register (accessible with LCR=0)
- */
-static void autoconfig_8250(struct uart_8250_port *up)
-{
-       unsigned char scratch, status1, status2;
-
-       up->port.type = PORT_8250;
-
-       scratch = serial_in(up, UART_SCR);
-       serial_out(up, UART_SCR, 0xa5);
-       status1 = serial_in(up, UART_SCR);
-       serial_out(up, UART_SCR, 0x5a);
-       status2 = serial_in(up, UART_SCR);
-       serial_out(up, UART_SCR, scratch);
-
-       if (status1 == 0xa5 && status2 == 0x5a)
-               up->port.type = PORT_16450;
-}
-
-static int broken_efr(struct uart_8250_port *up)
-{
-       /*
-        * Exar ST16C2550 "A2" devices incorrectly detect as
-        * having an EFR, and report an ID of 0x0201.  See
-        * http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-11/4812.html
-        */
-       if (autoconfig_read_divisor_id(up) == 0x0201 && size_fifo(up) == 16)
-               return 1;
-
-       return 0;
-}
-
-/*
- * We know that the chip has FIFOs.  Does it have an EFR?  The
- * EFR is located in the same register position as the IIR and
- * we know the top two bits of the IIR are currently set.  The
- * EFR should contain zero.  Try to read the EFR.
- */
-static void autoconfig_16550a(struct uart_8250_port *up)
-{
-       unsigned char status1, status2;
-       unsigned int iersave;
-
-       up->port.type = PORT_16550A;
-       up->capabilities |= UART_CAP_FIFO;
-
-       /*
-        * XR17V35x UARTs have an extra divisor register, DLD
-        * that gets enabled with when DLAB is set which will
-        * cause the device to incorrectly match and assign
-        * port type to PORT_16650.  The EFR for this UART is
-        * found at offset 0x09. Instead check the Deice ID (DVID)
-        * register for a 2, 4 or 8 port UART.
-        */
-       if (up->port.flags & UPF_EXAR_EFR) {
-               status1 = serial_in(up, UART_EXAR_DVID);
-               if (status1 == 0x82 || status1 == 0x84 || status1 == 0x88) {
-                       DEBUG_AUTOCONF("Exar XR17V35x ");
-                       up->port.type = PORT_XR17V35X;
-                       up->capabilities |= UART_CAP_AFE | UART_CAP_EFR |
-                                               UART_CAP_SLEEP;
-
-                       return;
-               }
-
-       }
-
-       /*
-        * Check for presence of the EFR when DLAB is set.
-        * Only ST16C650V1 UARTs pass this test.
-        */
-       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
-       if (serial_in(up, UART_EFR) == 0) {
-               serial_out(up, UART_EFR, 0xA8);
-               if (serial_in(up, UART_EFR) != 0) {
-                       DEBUG_AUTOCONF("EFRv1 ");
-                       up->port.type = PORT_16650;
-                       up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
-               } else {
-                       serial_out(up, UART_LCR, 0);
-                       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
-                                  UART_FCR7_64BYTE);
-                       status1 = serial_in(up, UART_IIR) >> 5;
-                       serial_out(up, UART_FCR, 0);
-                       serial_out(up, UART_LCR, 0);
-
-                       if (status1 == 7)
-                               up->port.type = PORT_16550A_FSL64;
-                       else
-                               DEBUG_AUTOCONF("Motorola 8xxx DUART ");
-               }
-               serial_out(up, UART_EFR, 0);
-               return;
-       }
-
-       /*
-        * Maybe it requires 0xbf to be written to the LCR.
-        * (other ST16C650V2 UARTs, TI16C752A, etc)
-        */
-       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
-       if (serial_in(up, UART_EFR) == 0 && !broken_efr(up)) {
-               DEBUG_AUTOCONF("EFRv2 ");
-               autoconfig_has_efr(up);
-               return;
-       }
-
-       /*
-        * Check for a National Semiconductor SuperIO chip.
-        * Attempt to switch to bank 2, read the value of the LOOP bit
-        * from EXCR1. Switch back to bank 0, change it in MCR. Then
-        * switch back to bank 2, read it from EXCR1 again and check
-        * it's changed. If so, set baud_base in EXCR2 to 921600. -- dwmw2
-        */
-       serial_out(up, UART_LCR, 0);
-       status1 = serial_in(up, UART_MCR);
-       serial_out(up, UART_LCR, 0xE0);
-       status2 = serial_in(up, 0x02); /* EXCR1 */
-
-       if (!((status2 ^ status1) & UART_MCR_LOOP)) {
-               serial_out(up, UART_LCR, 0);
-               serial_out(up, UART_MCR, status1 ^ UART_MCR_LOOP);
-               serial_out(up, UART_LCR, 0xE0);
-               status2 = serial_in(up, 0x02); /* EXCR1 */
-               serial_out(up, UART_LCR, 0);
-               serial_out(up, UART_MCR, status1);
-
-               if ((status2 ^ status1) & UART_MCR_LOOP) {
-                       unsigned short quot;
-
-                       serial_out(up, UART_LCR, 0xE0);
-
-                       quot = serial_dl_read(up);
-                       quot <<= 3;
-
-                       if (ns16550a_goto_highspeed(up))
-                               serial_dl_write(up, quot);
-
-                       serial_out(up, UART_LCR, 0);
-
-                       up->port.uartclk = 921600*16;
-                       up->port.type = PORT_NS16550A;
-                       up->capabilities |= UART_NATSEMI;
-                       return;
-               }
-       }
-
-       /*
-        * No EFR.  Try to detect a TI16750, which only sets bit 5 of
-        * the IIR when 64 byte FIFO mode is enabled when DLAB is set.
-        * Try setting it with and without DLAB set.  Cheap clones
-        * set bit 5 without DLAB set.
-        */
-       serial_out(up, UART_LCR, 0);
-       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
-       status1 = serial_in(up, UART_IIR) >> 5;
-       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
-       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
-       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
-       status2 = serial_in(up, UART_IIR) >> 5;
-       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
-       serial_out(up, UART_LCR, 0);
-
-       DEBUG_AUTOCONF("iir1=%d iir2=%d ", status1, status2);
-
-       if (status1 == 6 && status2 == 7) {
-               up->port.type = PORT_16750;
-               up->capabilities |= UART_CAP_AFE | UART_CAP_SLEEP;
-               return;
-       }
-
-       /*
-        * Try writing and reading the UART_IER_UUE bit (b6).
-        * If it works, this is probably one of the Xscale platform's
-        * internal UARTs.
-        * We're going to explicitly set the UUE bit to 0 before
-        * trying to write and read a 1 just to make sure it's not
-        * already a 1 and maybe locked there before we even start start.
-        */
-       iersave = serial_in(up, UART_IER);
-       serial_out(up, UART_IER, iersave & ~UART_IER_UUE);
-       if (!(serial_in(up, UART_IER) & UART_IER_UUE)) {
-               /*
-                * OK it's in a known zero state, try writing and reading
-                * without disturbing the current state of the other bits.
-                */
-               serial_out(up, UART_IER, iersave | UART_IER_UUE);
-               if (serial_in(up, UART_IER) & UART_IER_UUE) {
-                       /*
-                        * It's an Xscale.
-                        * We'll leave the UART_IER_UUE bit set to 1 (enabled).
-                        */
-                       DEBUG_AUTOCONF("Xscale ");
-                       up->port.type = PORT_XSCALE;
-                       up->capabilities |= UART_CAP_UUE | UART_CAP_RTOIE;
-                       return;
-               }
-       } else {
-               /*
-                * If we got here we couldn't force the IER_UUE bit to 0.
-                * Log it and continue.
-                */
-               DEBUG_AUTOCONF("Couldn't force IER_UUE to 0 ");
-       }
-       serial_out(up, UART_IER, iersave);
-
-       /*
-        * Exar uarts have EFR in a weird location
-        */
-       if (up->port.flags & UPF_EXAR_EFR) {
-               DEBUG_AUTOCONF("Exar XR17D15x ");
-               up->port.type = PORT_XR17D15X;
-               up->capabilities |= UART_CAP_AFE | UART_CAP_EFR |
-                                   UART_CAP_SLEEP;
-
-               return;
-       }
-
-       /*
-        * We distinguish between 16550A and U6 16550A by counting
-        * how many bytes are in the FIFO.
-        */
-       if (up->port.type == PORT_16550A && size_fifo(up) == 64) {
-               up->port.type = PORT_U6_16550A;
-               up->capabilities |= UART_CAP_AFE;
-       }
-}
-
-/*
- * This routine is called by rs_init() to initialize a specific serial
- * port.  It determines what type of UART chip this serial port is
- * using: 8250, 16450, 16550, 16550A.  The important question is
- * whether or not this UART is a 16550A or not, since this will
- * determine whether or not we can use its FIFO features or not.
- */
-static void autoconfig(struct uart_8250_port *up)
-{
-       unsigned char status1, scratch, scratch2, scratch3;
-       unsigned char save_lcr, save_mcr;
-       struct uart_port *port = &up->port;
-       unsigned long flags;
-       unsigned int old_capabilities;
-
-       if (!port->iobase && !port->mapbase && !port->membase)
-               return;
-
-       DEBUG_AUTOCONF("ttyS%d: autoconf (0x%04lx, 0x%p): ",
-                      serial_index(port), port->iobase, port->membase);
-
-       /*
-        * We really do need global IRQs disabled here - we're going to
-        * be frobbing the chips IRQ enable register to see if it exists.
-        */
-       spin_lock_irqsave(&port->lock, flags);
-
-       up->capabilities = 0;
-       up->bugs = 0;
-
-       if (!(port->flags & UPF_BUGGY_UART)) {
-               /*
-                * Do a simple existence test first; if we fail this,
-                * there's no point trying anything else.
-                *
-                * 0x80 is used as a nonsense port to prevent against
-                * false positives due to ISA bus float.  The
-                * assumption is that 0x80 is a non-existent port;
-                * which should be safe since include/asm/io.h also
-                * makes this assumption.
-                *
-                * Note: this is safe as long as MCR bit 4 is clear
-                * and the device is in "PC" mode.
-                */
-               scratch = serial_in(up, UART_IER);
-               serial_out(up, UART_IER, 0);
-#ifdef __i386__
-               outb(0xff, 0x080);
-#endif
-               /*
-                * Mask out IER[7:4] bits for test as some UARTs (e.g. TL
-                * 16C754B) allow only to modify them if an EFR bit is set.
-                */
-               scratch2 = serial_in(up, UART_IER) & 0x0f;
-               serial_out(up, UART_IER, 0x0F);
-#ifdef __i386__
-               outb(0, 0x080);
-#endif
-               scratch3 = serial_in(up, UART_IER) & 0x0f;
-               serial_out(up, UART_IER, scratch);
-               if (scratch2 != 0 || scratch3 != 0x0F) {
-                       /*
-                        * We failed; there's nothing here
-                        */
-                       spin_unlock_irqrestore(&port->lock, flags);
-                       DEBUG_AUTOCONF("IER test failed (%02x, %02x) ",
-                                      scratch2, scratch3);
-                       goto out;
-               }
-       }
-
-       save_mcr = serial_in(up, UART_MCR);
-       save_lcr = serial_in(up, UART_LCR);
-
-       /*
-        * Check to see if a UART is really there.  Certain broken
-        * internal modems based on the Rockwell chipset fail this
-        * test, because they apparently don't implement the loopback
-        * test mode.  So this test is skipped on the COM 1 through
-        * COM 4 ports.  This *should* be safe, since no board
-        * manufacturer would be stupid enough to design a board
-        * that conflicts with COM 1-4 --- we hope!
-        */
-       if (!(port->flags & UPF_SKIP_TEST)) {
-               serial_out(up, UART_MCR, UART_MCR_LOOP | 0x0A);
-               status1 = serial_in(up, UART_MSR) & 0xF0;
-               serial_out(up, UART_MCR, save_mcr);
-               if (status1 != 0x90) {
-                       spin_unlock_irqrestore(&port->lock, flags);
-                       DEBUG_AUTOCONF("LOOP test failed (%02x) ",
-                                      status1);
-                       goto out;
-               }
-       }
-
-       /*
-        * We're pretty sure there's a port here.  Lets find out what
-        * type of port it is.  The IIR top two bits allows us to find
-        * out if it's 8250 or 16450, 16550, 16550A or later.  This
-        * determines what we test for next.
-        *
-        * We also initialise the EFR (if any) to zero for later.  The
-        * EFR occupies the same register location as the FCR and IIR.
-        */
-       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
-       serial_out(up, UART_EFR, 0);
-       serial_out(up, UART_LCR, 0);
-
-       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
-       scratch = serial_in(up, UART_IIR) >> 6;
-
-       switch (scratch) {
-       case 0:
-               autoconfig_8250(up);
-               break;
-       case 1:
-               port->type = PORT_UNKNOWN;
-               break;
-       case 2:
-               port->type = PORT_16550;
-               break;
-       case 3:
-               autoconfig_16550a(up);
-               break;
-       }
-
-#ifdef CONFIG_SERIAL_8250_RSA
-       /*
-        * Only probe for RSA ports if we got the region.
-        */
-       if (port->type == PORT_16550A && up->probe & UART_PROBE_RSA &&
-           __enable_rsa(up))
-               port->type = PORT_RSA;
-#endif
-
-       serial_out(up, UART_LCR, save_lcr);
-
-       port->fifosize = uart_config[up->port.type].fifo_size;
-       old_capabilities = up->capabilities;
-       up->capabilities = uart_config[port->type].flags;
-       up->tx_loadsz = uart_config[port->type].tx_loadsz;
-
-       if (port->type == PORT_UNKNOWN)
-               goto out_lock;
-
-       /*
-        * Reset the UART.
-        */
-#ifdef CONFIG_SERIAL_8250_RSA
-       if (port->type == PORT_RSA)
-               serial_out(up, UART_RSA_FRR, 0);
-#endif
-       serial_out(up, UART_MCR, save_mcr);
-       serial8250_clear_fifos(up);
-       serial_in(up, UART_RX);
-       if (up->capabilities & UART_CAP_UUE)
-               serial_out(up, UART_IER, UART_IER_UUE);
-       else
-               serial_out(up, UART_IER, 0);
-
-out_lock:
-       spin_unlock_irqrestore(&port->lock, flags);
-       if (up->capabilities != old_capabilities) {
-               printk(KERN_WARNING
-                      "ttyS%d: detected caps %08x should be %08x\n",
-                      serial_index(port), old_capabilities,
-                      up->capabilities);
-       }
-out:
-       DEBUG_AUTOCONF("iir=%d ", scratch);
-       DEBUG_AUTOCONF("type=%s\n", uart_config[port->type].name);
-}
-
-static void autoconfig_irq(struct uart_8250_port *up)
-{
-       struct uart_port *port = &up->port;
-       unsigned char save_mcr, save_ier;
-       unsigned char save_ICP = 0;
-       unsigned int ICP = 0;
-       unsigned long irqs;
-       int irq;
-
-       if (port->flags & UPF_FOURPORT) {
-               ICP = (port->iobase & 0xfe0) | 0x1f;
-               save_ICP = inb_p(ICP);
-               outb_p(0x80, ICP);
-               inb_p(ICP);
-       }
-
-       /* forget possible initially masked and pending IRQ */
-       probe_irq_off(probe_irq_on());
-       save_mcr = serial_in(up, UART_MCR);
-       save_ier = serial_in(up, UART_IER);
-       serial_out(up, UART_MCR, UART_MCR_OUT1 | UART_MCR_OUT2);
-
-       irqs = probe_irq_on();
-       serial_out(up, UART_MCR, 0);
-       udelay(10);
-       if (port->flags & UPF_FOURPORT) {
-               serial_out(up, UART_MCR,
-                           UART_MCR_DTR | UART_MCR_RTS);
-       } else {
-               serial_out(up, UART_MCR,
-                           UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2);
-       }
-       serial_out(up, UART_IER, 0x0f); /* enable all intrs */
-       serial_in(up, UART_LSR);
-       serial_in(up, UART_RX);
-       serial_in(up, UART_IIR);
-       serial_in(up, UART_MSR);
-       serial_out(up, UART_TX, 0xFF);
-       udelay(20);
-       irq = probe_irq_off(irqs);
-
-       serial_out(up, UART_MCR, save_mcr);
-       serial_out(up, UART_IER, save_ier);
-
-       if (port->flags & UPF_FOURPORT)
-               outb_p(save_ICP, ICP);
-
-       port->irq = (irq > 0) ? irq : 0;
-}
-
-static inline void __stop_tx(struct uart_8250_port *p)
-{
-       if (p->ier & UART_IER_THRI) {
-               p->ier &= ~UART_IER_THRI;
-               serial_out(p, UART_IER, p->ier);
-               serial8250_rpm_put_tx(p);
-       }
-}
-
-static void serial8250_stop_tx(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-
-       serial8250_rpm_get(up);
-       __stop_tx(up);
-
-       /*
-        * We really want to stop the transmitter from sending.
-        */
-       if (port->type == PORT_16C950) {
-               up->acr |= UART_ACR_TXDIS;
-               serial_icr_write(up, UART_ACR, up->acr);
-       }
-       serial8250_rpm_put(up);
-}
-
-static void serial8250_start_tx(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-
-       serial8250_rpm_get_tx(up);
-
-       if (up->dma && !up->dma->tx_dma(up))
-               return;
-
-       if (!(up->ier & UART_IER_THRI)) {
-               up->ier |= UART_IER_THRI;
-               serial_port_out(port, UART_IER, up->ier);
-
-               if (up->bugs & UART_BUG_TXEN) {
-                       unsigned char lsr;
-                       lsr = serial_in(up, UART_LSR);
-                       up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
-                       if (lsr & UART_LSR_THRE)
-                               serial8250_tx_chars(up);
-               }
-       }
-
-       /*
-        * Re-enable the transmitter if we disabled it.
-        */
-       if (port->type == PORT_16C950 && up->acr & UART_ACR_TXDIS) {
-               up->acr &= ~UART_ACR_TXDIS;
-               serial_icr_write(up, UART_ACR, up->acr);
-       }
-}
-
-static void serial8250_throttle(struct uart_port *port)
-{
-       port->throttle(port);
-}
-
-static void serial8250_unthrottle(struct uart_port *port)
-{
-       port->unthrottle(port);
-}
-
-static void serial8250_stop_rx(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-
-       serial8250_rpm_get(up);
-
-       up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
-       up->port.read_status_mask &= ~UART_LSR_DR;
-       serial_port_out(port, UART_IER, up->ier);
-
-       serial8250_rpm_put(up);
-}
-
-static void serial8250_disable_ms(struct uart_port *port)
-{
-       struct uart_8250_port *up =
-               container_of(port, struct uart_8250_port, port);
-
-       /* no MSR capabilities */
-       if (up->bugs & UART_BUG_NOMSR)
-               return;
-
-       up->ier &= ~UART_IER_MSI;
-       serial_port_out(port, UART_IER, up->ier);
-}
-
-static void serial8250_enable_ms(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-
-       /* no MSR capabilities */
-       if (up->bugs & UART_BUG_NOMSR)
-               return;
-
-       up->ier |= UART_IER_MSI;
-
-       serial8250_rpm_get(up);
-       serial_port_out(port, UART_IER, up->ier);
-       serial8250_rpm_put(up);
-}
-
-/*
- * serial8250_rx_chars: processes according to the passed in LSR
- * value, and returns the remaining LSR bits not handled
- * by this Rx routine.
- */
-unsigned char
-serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
-{
-       struct uart_port *port = &up->port;
-       unsigned char ch;
-       int max_count = 256;
-       char flag;
-
-       do {
-               if (likely(lsr & UART_LSR_DR))
-                       ch = serial_in(up, UART_RX);
-               else
-                       /*
-                        * Intel 82571 has a Serial Over Lan device that will
-                        * set UART_LSR_BI without setting UART_LSR_DR when
-                        * it receives a break. To avoid reading from the
-                        * receive buffer without UART_LSR_DR bit set, we
-                        * just force the read character to be 0
-                        */
-                       ch = 0;
-
-               flag = TTY_NORMAL;
-               port->icount.rx++;
-
-               lsr |= up->lsr_saved_flags;
-               up->lsr_saved_flags = 0;
-
-               if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
-                       if (lsr & UART_LSR_BI) {
-                               lsr &= ~(UART_LSR_FE | UART_LSR_PE);
-                               port->icount.brk++;
-                               /*
-                                * We do the SysRQ and SAK checking
-                                * here because otherwise the break
-                                * may get masked by ignore_status_mask
-                                * or read_status_mask.
-                                */
-                               if (uart_handle_break(port))
-                                       goto ignore_char;
-                       } else if (lsr & UART_LSR_PE)
-                               port->icount.parity++;
-                       else if (lsr & UART_LSR_FE)
-                               port->icount.frame++;
-                       if (lsr & UART_LSR_OE)
-                               port->icount.overrun++;
-
-                       /*
-                        * Mask off conditions which should be ignored.
-                        */
-                       lsr &= port->read_status_mask;
-
-                       if (lsr & UART_LSR_BI) {
-                               DEBUG_INTR("handling break....");
-                               flag = TTY_BREAK;
-                       } else if (lsr & UART_LSR_PE)
-                               flag = TTY_PARITY;
-                       else if (lsr & UART_LSR_FE)
-                               flag = TTY_FRAME;
-               }
-               if (uart_handle_sysrq_char(port, ch))
-                       goto ignore_char;
-
-               uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
-
-ignore_char:
-               lsr = serial_in(up, UART_LSR);
-       } while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (--max_count > 0));
-       spin_unlock(&port->lock);
-       tty_flip_buffer_push(&port->state->port);
-       spin_lock(&port->lock);
-       return lsr;
-}
-EXPORT_SYMBOL_GPL(serial8250_rx_chars);
-
-void serial8250_tx_chars(struct uart_8250_port *up)
-{
-       struct uart_port *port = &up->port;
-       struct circ_buf *xmit = &port->state->xmit;
-       int count;
-
-       if (port->x_char) {
-               serial_out(up, UART_TX, port->x_char);
-               port->icount.tx++;
-               port->x_char = 0;
-               return;
-       }
-       if (uart_tx_stopped(port)) {
-               serial8250_stop_tx(port);
-               return;
-       }
-       if (uart_circ_empty(xmit)) {
-               __stop_tx(up);
-               return;
-       }
-
-       count = up->tx_loadsz;
-       do {
-               serial_out(up, UART_TX, xmit->buf[xmit->tail]);
-               xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
-               port->icount.tx++;
-               if (uart_circ_empty(xmit))
-                       break;
-               if (up->capabilities & UART_CAP_HFIFO) {
-                       if ((serial_port_in(port, UART_LSR) & BOTH_EMPTY) !=
-                           BOTH_EMPTY)
-                               break;
-               }
-       } while (--count > 0);
-
-       if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
-               uart_write_wakeup(port);
-
-       DEBUG_INTR("THRE...");
-
-       /*
-        * With RPM enabled, we have to wait until the FIFO is empty before the
-        * HW can go idle. So we get here once again with empty FIFO and disable
-        * the interrupt and RPM in __stop_tx()
-        */
-       if (uart_circ_empty(xmit) && !(up->capabilities & UART_CAP_RPM))
-               __stop_tx(up);
-}
-EXPORT_SYMBOL_GPL(serial8250_tx_chars);
-
-/* Caller holds uart port lock */
-unsigned int serial8250_modem_status(struct uart_8250_port *up)
-{
-       struct uart_port *port = &up->port;
-       unsigned int status = serial_in(up, UART_MSR);
-
-       status |= up->msr_saved_flags;
-       up->msr_saved_flags = 0;
-       if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI &&
-           port->state != NULL) {
-               if (status & UART_MSR_TERI)
-                       port->icount.rng++;
-               if (status & UART_MSR_DDSR)
-                       port->icount.dsr++;
-               if (status & UART_MSR_DDCD)
-                       uart_handle_dcd_change(port, status & UART_MSR_DCD);
-               if (status & UART_MSR_DCTS)
-                       uart_handle_cts_change(port, status & UART_MSR_CTS);
-
-               wake_up_interruptible(&port->state->port.delta_msr_wait);
-       }
-
-       return status;
-}
-EXPORT_SYMBOL_GPL(serial8250_modem_status);
-
-/*
- * This handles the interrupt from one port.
- */
-int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
-{
-       unsigned char status;
-       unsigned long flags;
-       struct uart_8250_port *up = up_to_u8250p(port);
-       int dma_err = 0;
-
-       if (iir & UART_IIR_NO_INT)
-               return 0;
-
-       spin_lock_irqsave(&port->lock, flags);
-
-       status = serial_port_in(port, UART_LSR);
-
-       DEBUG_INTR("status = %x...", status);
-
-       if (status & (UART_LSR_DR | UART_LSR_BI)) {
-               if (up->dma)
-                       dma_err = up->dma->rx_dma(up, iir);
-
-               if (!up->dma || dma_err)
-                       status = serial8250_rx_chars(up, status);
-       }
-       serial8250_modem_status(up);
-       if ((!up->dma || (up->dma && up->dma->tx_err)) &&
-           (status & UART_LSR_THRE))
-               serial8250_tx_chars(up);
-
-       spin_unlock_irqrestore(&port->lock, flags);
-       return 1;
-}
-EXPORT_SYMBOL_GPL(serial8250_handle_irq);
-
-static int serial8250_default_handle_irq(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       unsigned int iir;
-       int ret;
-
-       serial8250_rpm_get(up);
-
-       iir = serial_port_in(port, UART_IIR);
-       ret = serial8250_handle_irq(port, iir);
-
-       serial8250_rpm_put(up);
-       return ret;
-}
-
-/*
- * These Exar UARTs have an extra interrupt indicator that could
- * fire for a few unimplemented interrupts.  One of which is a
- * wakeup event when coming out of sleep.  Put this here just
- * to be on the safe side that these interrupts don't go unhandled.
- */
-static int exar_handle_irq(struct uart_port *port)
-{
-       unsigned char int0, int1, int2, int3;
-       unsigned int iir = serial_port_in(port, UART_IIR);
-       int ret;
-
-       ret = serial8250_handle_irq(port, iir);
-
-       if ((port->type == PORT_XR17V35X) ||
-          (port->type == PORT_XR17D15X)) {
-               int0 = serial_port_in(port, 0x80);
-               int1 = serial_port_in(port, 0x81);
-               int2 = serial_port_in(port, 0x82);
-               int3 = serial_port_in(port, 0x83);
-       }
-
-       return ret;
-}
-
-/*
- * This is the serial driver's interrupt routine.
- *
- * Arjan thinks the old way was overly complex, so it got simplified.
- * Alan disagrees, saying that need the complexity to handle the weird
- * nature of ISA shared interrupts.  (This is a special exception.)
- *
- * In order to handle ISA shared interrupts properly, we need to check
- * that all ports have been serviced, and therefore the ISA interrupt
- * line has been de-asserted.
- *
- * This means we need to loop through all ports. checking that they
- * don't have an interrupt pending.
- */
-static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
-{
-       struct irq_info *i = dev_id;
-       struct list_head *l, *end = NULL;
-       int pass_counter = 0, handled = 0;
-
-       DEBUG_INTR("serial8250_interrupt(%d)...", irq);
-
-       spin_lock(&i->lock);
-
-       l = i->head;
-       do {
-               struct uart_8250_port *up;
-               struct uart_port *port;
-
-               up = list_entry(l, struct uart_8250_port, list);
-               port = &up->port;
-
-               if (port->handle_irq(port)) {
-                       handled = 1;
-                       end = NULL;
-               } else if (end == NULL)
-                       end = l;
-
-               l = l->next;
-
-               if (l == i->head && pass_counter++ > PASS_LIMIT) {
-                       /* If we hit this, we're dead. */
-                       printk_ratelimited(KERN_ERR
-                               "serial8250: too much work for irq%d\n", irq);
-                       break;
-               }
-       } while (l != end);
-
-       spin_unlock(&i->lock);
-
-       DEBUG_INTR("end.\n");
-
-       return IRQ_RETVAL(handled);
-}
-
-/*
- * To support ISA shared interrupts, we need to have one interrupt
- * handler that ensures that the IRQ line has been deasserted
- * before returning.  Failing to do this will result in the IRQ
- * line being stuck active, and, since ISA irqs are edge triggered,
- * no more IRQs will be seen.
- */
-static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
-{
-       spin_lock_irq(&i->lock);
-
-       if (!list_empty(i->head)) {
-               if (i->head == &up->list)
-                       i->head = i->head->next;
-               list_del(&up->list);
-       } else {
-               BUG_ON(i->head != &up->list);
-               i->head = NULL;
-       }
-       spin_unlock_irq(&i->lock);
-       /* List empty so throw away the hash node */
-       if (i->head == NULL) {
-               hlist_del(&i->node);
-               kfree(i);
-       }
-}
-
-static int serial_link_irq_chain(struct uart_8250_port *up)
-{
-       struct hlist_head *h;
-       struct hlist_node *n;
-       struct irq_info *i;
-       int ret, irq_flags = up->port.flags & UPF_SHARE_IRQ ? IRQF_SHARED : 0;
-
-       mutex_lock(&hash_mutex);
-
-       h = &irq_lists[up->port.irq % NR_IRQ_HASH];
-
-       hlist_for_each(n, h) {
-               i = hlist_entry(n, struct irq_info, node);
-               if (i->irq == up->port.irq)
-                       break;
-       }
-
-       if (n == NULL) {
-               i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
-               if (i == NULL) {
-                       mutex_unlock(&hash_mutex);
-                       return -ENOMEM;
-               }
-               spin_lock_init(&i->lock);
-               i->irq = up->port.irq;
-               hlist_add_head(&i->node, h);
-       }
-       mutex_unlock(&hash_mutex);
-
-       spin_lock_irq(&i->lock);
-
-       if (i->head) {
-               list_add(&up->list, i->head);
-               spin_unlock_irq(&i->lock);
-
-               ret = 0;
-       } else {
-               INIT_LIST_HEAD(&up->list);
-               i->head = &up->list;
-               spin_unlock_irq(&i->lock);
-               irq_flags |= up->port.irqflags;
-               ret = request_irq(up->port.irq, serial8250_interrupt,
-                                 irq_flags, "serial", i);
-               if (ret < 0)
-                       serial_do_unlink(i, up);
-       }
-
-       return ret;
-}
-
-static void serial_unlink_irq_chain(struct uart_8250_port *up)
-{
-       /*
-        * yes, some broken gcc emit "warning: 'i' may be used uninitialized"
-        * but no, we are not going to take a patch that assigns NULL below.
-        */
-       struct irq_info *i;
-       struct hlist_node *n;
-       struct hlist_head *h;
-
-       mutex_lock(&hash_mutex);
-
-       h = &irq_lists[up->port.irq % NR_IRQ_HASH];
-
-       hlist_for_each(n, h) {
-               i = hlist_entry(n, struct irq_info, node);
-               if (i->irq == up->port.irq)
-                       break;
-       }
-
-       BUG_ON(n == NULL);
-       BUG_ON(i->head == NULL);
-
-       if (list_empty(i->head))
-               free_irq(up->port.irq, i);
-
-       serial_do_unlink(i, up);
-       mutex_unlock(&hash_mutex);
-}
-
-/*
- * This function is used to handle ports that do not have an
- * interrupt.  This doesn't work very well for 16450's, but gives
- * barely passable results for a 16550A.  (Although at the expense
- * of much CPU overhead).
- */
-static void serial8250_timeout(unsigned long data)
-{
-       struct uart_8250_port *up = (struct uart_8250_port *)data;
-
-       up->port.handle_irq(&up->port);
-       mod_timer(&up->timer, jiffies + uart_poll_timeout(&up->port));
-}
-
-static void serial8250_backup_timeout(unsigned long data)
-{
-       struct uart_8250_port *up = (struct uart_8250_port *)data;
-       unsigned int iir, ier = 0, lsr;
-       unsigned long flags;
-
-       spin_lock_irqsave(&up->port.lock, flags);
-
-       /*
-        * Must disable interrupts or else we risk racing with the interrupt
-        * based handler.
-        */
-       if (up->port.irq) {
-               ier = serial_in(up, UART_IER);
-               serial_out(up, UART_IER, 0);
-       }
-
-       iir = serial_in(up, UART_IIR);
-
-       /*
-        * This should be a safe test for anyone who doesn't trust the
-        * IIR bits on their UART, but it's specifically designed for
-        * the "Diva" UART used on the management processor on many HP
-        * ia64 and parisc boxes.
-        */
-       lsr = serial_in(up, UART_LSR);
-       up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
-       if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
-           (!uart_circ_empty(&up->port.state->xmit) || up->port.x_char) &&
-           (lsr & UART_LSR_THRE)) {
-               iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
-               iir |= UART_IIR_THRI;
-       }
-
-       if (!(iir & UART_IIR_NO_INT))
-               serial8250_tx_chars(up);
-
-       if (up->port.irq)
-               serial_out(up, UART_IER, ier);
-
-       spin_unlock_irqrestore(&up->port.lock, flags);
-
-       /* Standard timer interval plus 0.2s to keep the port running */
-       mod_timer(&up->timer,
-               jiffies + uart_poll_timeout(&up->port) + HZ / 5);
-}
-
-static int univ8250_setup_irq(struct uart_8250_port *up)
-{
-       struct uart_port *port = &up->port;
-       int retval = 0;
-
-       /*
-        * The above check will only give an accurate result the first time
-        * the port is opened so this value needs to be preserved.
-        */
-       if (up->bugs & UART_BUG_THRE) {
-               pr_debug("ttyS%d - using backup timer\n", serial_index(port));
-
-               up->timer.function = serial8250_backup_timeout;
-               up->timer.data = (unsigned long)up;
-               mod_timer(&up->timer, jiffies +
-                         uart_poll_timeout(port) + HZ / 5);
-       }
-
-       /*
-        * If the "interrupt" for this port doesn't correspond with any
-        * hardware interrupt, we use a timer-based system.  The original
-        * driver used to do this with IRQ0.
-        */
-       if (!port->irq) {
-               up->timer.data = (unsigned long)up;
-               mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
-       } else
-               retval = serial_link_irq_chain(up);
-
-       return retval;
-}
-
-static void univ8250_release_irq(struct uart_8250_port *up)
-{
-       struct uart_port *port = &up->port;
-
-       del_timer_sync(&up->timer);
-       up->timer.function = serial8250_timeout;
-       if (port->irq)
-               serial_unlink_irq_chain(up);
-}
-
-static unsigned int serial8250_tx_empty(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       unsigned long flags;
-       unsigned int lsr;
-
-       serial8250_rpm_get(up);
-
-       spin_lock_irqsave(&port->lock, flags);
-       lsr = serial_port_in(port, UART_LSR);
-       up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
-       spin_unlock_irqrestore(&port->lock, flags);
-
-       serial8250_rpm_put(up);
-
-       return (lsr & BOTH_EMPTY) == BOTH_EMPTY ? TIOCSER_TEMT : 0;
-}
-
-static unsigned int serial8250_get_mctrl(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       unsigned int status;
-       unsigned int ret;
-
-       serial8250_rpm_get(up);
-       status = serial8250_modem_status(up);
-       serial8250_rpm_put(up);
-
-       ret = 0;
-       if (status & UART_MSR_DCD)
-               ret |= TIOCM_CAR;
-       if (status & UART_MSR_RI)
-               ret |= TIOCM_RNG;
-       if (status & UART_MSR_DSR)
-               ret |= TIOCM_DSR;
-       if (status & UART_MSR_CTS)
-               ret |= TIOCM_CTS;
-       return ret;
-}
-
-void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       unsigned char mcr = 0;
-
-       if (mctrl & TIOCM_RTS)
-               mcr |= UART_MCR_RTS;
-       if (mctrl & TIOCM_DTR)
-               mcr |= UART_MCR_DTR;
-       if (mctrl & TIOCM_OUT1)
-               mcr |= UART_MCR_OUT1;
-       if (mctrl & TIOCM_OUT2)
-               mcr |= UART_MCR_OUT2;
-       if (mctrl & TIOCM_LOOP)
-               mcr |= UART_MCR_LOOP;
-
-       mcr = (mcr & up->mcr_mask) | up->mcr_force | up->mcr;
-
-       serial_port_out(port, UART_MCR, mcr);
-}
-EXPORT_SYMBOL_GPL(serial8250_do_set_mctrl);
-
-static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
-{
-       if (port->set_mctrl)
-               port->set_mctrl(port, mctrl);
-       else
-               serial8250_do_set_mctrl(port, mctrl);
-}
-
-static void serial8250_break_ctl(struct uart_port *port, int break_state)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       unsigned long flags;
-
-       serial8250_rpm_get(up);
-       spin_lock_irqsave(&port->lock, flags);
-       if (break_state == -1)
-               up->lcr |= UART_LCR_SBC;
-       else
-               up->lcr &= ~UART_LCR_SBC;
-       serial_port_out(port, UART_LCR, up->lcr);
-       spin_unlock_irqrestore(&port->lock, flags);
-       serial8250_rpm_put(up);
-}
-
-/*
- *     Wait for transmitter & holding register to empty
- */
-static void wait_for_xmitr(struct uart_8250_port *up, int bits)
-{
-       unsigned int status, tmout = 10000;
-
-       /* Wait up to 10ms for the character(s) to be sent. */
-       for (;;) {
-               status = serial_in(up, UART_LSR);
-
-               up->lsr_saved_flags |= status & LSR_SAVE_FLAGS;
-
-               if ((status & bits) == bits)
-                       break;
-               if (--tmout == 0)
-                       break;
-               udelay(1);
-       }
-
-       /* Wait up to 1s for flow control if necessary */
-       if (up->port.flags & UPF_CONS_FLOW) {
-               unsigned int tmout;
-               for (tmout = 1000000; tmout; tmout--) {
-                       unsigned int msr = serial_in(up, UART_MSR);
-                       up->msr_saved_flags |= msr & MSR_SAVE_FLAGS;
-                       if (msr & UART_MSR_CTS)
-                               break;
-                       udelay(1);
-                       touch_nmi_watchdog();
-               }
-       }
-}
-
-#ifdef CONFIG_CONSOLE_POLL
-/*
- * Console polling routines for writing and reading from the uart while
- * in an interrupt or debug context.
- */
-
-static int serial8250_get_poll_char(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       unsigned char lsr;
-       int status;
-
-       serial8250_rpm_get(up);
-
-       lsr = serial_port_in(port, UART_LSR);
-
-       if (!(lsr & UART_LSR_DR)) {
-               status = NO_POLL_CHAR;
-               goto out;
-       }
-
-       status = serial_port_in(port, UART_RX);
-out:
-       serial8250_rpm_put(up);
-       return status;
-}
-
-
-static void serial8250_put_poll_char(struct uart_port *port,
-                        unsigned char c)
-{
-       unsigned int ier;
-       struct uart_8250_port *up = up_to_u8250p(port);
-
-       serial8250_rpm_get(up);
-       /*
-        *      First save the IER then disable the interrupts
-        */
-       ier = serial_port_in(port, UART_IER);
-       if (up->capabilities & UART_CAP_UUE)
-               serial_port_out(port, UART_IER, UART_IER_UUE);
-       else
-               serial_port_out(port, UART_IER, 0);
-
-       wait_for_xmitr(up, BOTH_EMPTY);
-       /*
-        *      Send the character out.
-        */
-       serial_port_out(port, UART_TX, c);
-
-       /*
-        *      Finally, wait for transmitter to become empty
-        *      and restore the IER
-        */
-       wait_for_xmitr(up, BOTH_EMPTY);
-       serial_port_out(port, UART_IER, ier);
-       serial8250_rpm_put(up);
-}
-
-#endif /* CONFIG_CONSOLE_POLL */
-
-int serial8250_do_startup(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       unsigned long flags;
-       unsigned char lsr, iir;
-       int retval;
-
-       if (port->type == PORT_8250_CIR)
-               return -ENODEV;
-
-       if (!port->fifosize)
-               port->fifosize = uart_config[port->type].fifo_size;
-       if (!up->tx_loadsz)
-               up->tx_loadsz = uart_config[port->type].tx_loadsz;
-       if (!up->capabilities)
-               up->capabilities = uart_config[port->type].flags;
-       up->mcr = 0;
-
-       if (port->iotype != up->cur_iotype)
-               set_io_from_upio(port);
-
-       serial8250_rpm_get(up);
-       if (port->type == PORT_16C950) {
-               /* Wake up and initialize UART */
-               up->acr = 0;
-               serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
-               serial_port_out(port, UART_EFR, UART_EFR_ECB);
-               serial_port_out(port, UART_IER, 0);
-               serial_port_out(port, UART_LCR, 0);
-               serial_icr_write(up, UART_CSR, 0); /* Reset the UART */
-               serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
-               serial_port_out(port, UART_EFR, UART_EFR_ECB);
-               serial_port_out(port, UART_LCR, 0);
-       }
-
-#ifdef CONFIG_SERIAL_8250_RSA
-       /*
-        * If this is an RSA port, see if we can kick it up to the
-        * higher speed clock.
-        */
-       enable_rsa(up);
-#endif
-       /*
-        * Clear the FIFO buffers and disable them.
-        * (they will be reenabled in set_termios())
-        */
-       serial8250_clear_fifos(up);
-
-       /*
-        * Clear the interrupt registers.
-        */
-       serial_port_in(port, UART_LSR);
-       serial_port_in(port, UART_RX);
-       serial_port_in(port, UART_IIR);
-       serial_port_in(port, UART_MSR);
-
-       /*
-        * At this point, there's no way the LSR could still be 0xff;
-        * if it is, then bail out, because there's likely no UART
-        * here.
-        */
-       if (!(port->flags & UPF_BUGGY_UART) &&
-           (serial_port_in(port, UART_LSR) == 0xff)) {
-               printk_ratelimited(KERN_INFO "ttyS%d: LSR safety check engaged!\n",
-                                  serial_index(port));
-               retval = -ENODEV;
-               goto out;
-       }
-
-       /*
-        * For a XR16C850, we need to set the trigger levels
-        */
-       if (port->type == PORT_16850) {
-               unsigned char fctr;
-
-               serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
-
-               fctr = serial_in(up, UART_FCTR) & ~(UART_FCTR_RX|UART_FCTR_TX);
-               serial_port_out(port, UART_FCTR,
-                               fctr | UART_FCTR_TRGD | UART_FCTR_RX);
-               serial_port_out(port, UART_TRG, UART_TRG_96);
-               serial_port_out(port, UART_FCTR,
-                               fctr | UART_FCTR_TRGD | UART_FCTR_TX);
-               serial_port_out(port, UART_TRG, UART_TRG_96);
-
-               serial_port_out(port, UART_LCR, 0);
-       }
-
-       if (port->irq) {
-               unsigned char iir1;
-               /*
-                * Test for UARTs that do not reassert THRE when the
-                * transmitter is idle and the interrupt has already
-                * been cleared.  Real 16550s should always reassert
-                * this interrupt whenever the transmitter is idle and
-                * the interrupt is enabled.  Delays are necessary to
-                * allow register changes to become visible.
-                */
-               spin_lock_irqsave(&port->lock, flags);
-               if (up->port.irqflags & IRQF_SHARED)
-                       disable_irq_nosync(port->irq);
-
-               wait_for_xmitr(up, UART_LSR_THRE);
-               serial_port_out_sync(port, UART_IER, UART_IER_THRI);
-               udelay(1); /* allow THRE to set */
-               iir1 = serial_port_in(port, UART_IIR);
-               serial_port_out(port, UART_IER, 0);
-               serial_port_out_sync(port, UART_IER, UART_IER_THRI);
-               udelay(1); /* allow a working UART time to re-assert THRE */
-               iir = serial_port_in(port, UART_IIR);
-               serial_port_out(port, UART_IER, 0);
-
-               if (port->irqflags & IRQF_SHARED)
-                       enable_irq(port->irq);
-               spin_unlock_irqrestore(&port->lock, flags);
-
-               /*
-                * If the interrupt is not reasserted, or we otherwise
-                * don't trust the iir, setup a timer to kick the UART
-                * on a regular basis.
-                */
-               if ((!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) ||
-                   up->port.flags & UPF_BUG_THRE) {
-                       up->bugs |= UART_BUG_THRE;
-               }
-       }
-
-       retval = up->ops->setup_irq(up);
-       if (retval)
-               goto out;
-
-       /*
-        * Now, initialize the UART
-        */
-       serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
-
-       spin_lock_irqsave(&port->lock, flags);
-       if (up->port.flags & UPF_FOURPORT) {
-               if (!up->port.irq)
-                       up->port.mctrl |= TIOCM_OUT1;
-       } else
-               /*
-                * Most PC uarts need OUT2 raised to enable interrupts.
-                */
-               if (port->irq)
-                       up->port.mctrl |= TIOCM_OUT2;
-
-       serial8250_set_mctrl(port, port->mctrl);
-
-       /* Serial over Lan (SoL) hack:
-          Intel 8257x Gigabit ethernet chips have a
-          16550 emulation, to be used for Serial Over Lan.
-          Those chips take a longer time than a normal
-          serial device to signalize that a transmission
-          data was queued. Due to that, the above test generally
-          fails. One solution would be to delay the reading of
-          iir. However, this is not reliable, since the timeout
-          is variable. So, let's just don't test if we receive
-          TX irq. This way, we'll never enable UART_BUG_TXEN.
-        */
-       if (up->port.flags & UPF_NO_TXEN_TEST)
-               goto dont_test_tx_en;
-
-       /*
-        * Do a quick test to see if we receive an
-        * interrupt when we enable the TX irq.
-        */
-       serial_port_out(port, UART_IER, UART_IER_THRI);
-       lsr = serial_port_in(port, UART_LSR);
-       iir = serial_port_in(port, UART_IIR);
-       serial_port_out(port, UART_IER, 0);
-
-       if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT) {
-               if (!(up->bugs & UART_BUG_TXEN)) {
-                       up->bugs |= UART_BUG_TXEN;
-                       pr_debug("ttyS%d - enabling bad tx status workarounds\n",
-                                serial_index(port));
-               }
-       } else {
-               up->bugs &= ~UART_BUG_TXEN;
-       }
-
-dont_test_tx_en:
-       spin_unlock_irqrestore(&port->lock, flags);
-
-       /*
-        * Clear the interrupt registers again for luck, and clear the
-        * saved flags to avoid getting false values from polling
-        * routines or the previous session.
-        */
-       serial_port_in(port, UART_LSR);
-       serial_port_in(port, UART_RX);
-       serial_port_in(port, UART_IIR);
-       serial_port_in(port, UART_MSR);
-       up->lsr_saved_flags = 0;
-       up->msr_saved_flags = 0;
-
-       /*
-        * Request DMA channels for both RX and TX.
-        */
-       if (up->dma) {
-               retval = serial8250_request_dma(up);
-               if (retval) {
-                       pr_warn_ratelimited("ttyS%d - failed to request DMA\n",
-                                           serial_index(port));
-                       up->dma = NULL;
-               }
-       }
-
-       /*
-        * Finally, enable interrupts.  Note: Modem status interrupts
-        * are set via set_termios(), which will be occurring imminently
-        * anyway, so we don't enable them here.
-        */
-       up->ier = UART_IER_RLSI | UART_IER_RDI;
-       serial_port_out(port, UART_IER, up->ier);
-
-       if (port->flags & UPF_FOURPORT) {
-               unsigned int icp;
-               /*
-                * Enable interrupts on the AST Fourport board
-                */
-               icp = (port->iobase & 0xfe0) | 0x01f;
-               outb_p(0x80, icp);
-               inb_p(icp);
-       }
-       retval = 0;
-out:
-       serial8250_rpm_put(up);
-       return retval;
-}
-EXPORT_SYMBOL_GPL(serial8250_do_startup);
-
-static int serial8250_startup(struct uart_port *port)
-{
-       if (port->startup)
-               return port->startup(port);
-       return serial8250_do_startup(port);
-}
-
-void serial8250_do_shutdown(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       unsigned long flags;
-
-       serial8250_rpm_get(up);
-       /*
-        * Disable interrupts from this port
-        */
-       up->ier = 0;
-       serial_port_out(port, UART_IER, 0);
-
-       if (up->dma)
-               serial8250_release_dma(up);
-
-       spin_lock_irqsave(&port->lock, flags);
-       if (port->flags & UPF_FOURPORT) {
-               /* reset interrupts on the AST Fourport board */
-               inb((port->iobase & 0xfe0) | 0x1f);
-               port->mctrl |= TIOCM_OUT1;
-       } else
-               port->mctrl &= ~TIOCM_OUT2;
-
-       serial8250_set_mctrl(port, port->mctrl);
-       spin_unlock_irqrestore(&port->lock, flags);
-
-       /*
-        * Disable break condition and FIFOs
-        */
-       serial_port_out(port, UART_LCR,
-                       serial_port_in(port, UART_LCR) & ~UART_LCR_SBC);
-       serial8250_clear_fifos(up);
-
-#ifdef CONFIG_SERIAL_8250_RSA
-       /*
-        * Reset the RSA board back to 115kbps compat mode.
-        */
-       disable_rsa(up);
-#endif
-
-       /*
-        * Read data port to reset things, and then unlink from
-        * the IRQ chain.
-        */
-       serial_port_in(port, UART_RX);
-       serial8250_rpm_put(up);
-
-       up->ops->release_irq(up);
-}
-EXPORT_SYMBOL_GPL(serial8250_do_shutdown);
-
-static void serial8250_shutdown(struct uart_port *port)
-{
-       if (port->shutdown)
-               port->shutdown(port);
-       else
-               serial8250_do_shutdown(port);
-}
-
-/*
- * XR17V35x UARTs have an extra fractional divisor register (DLD)
- * Calculate divisor with extra 4-bit fractional portion
- */
-static unsigned int xr17v35x_get_divisor(struct uart_8250_port *up,
-                                        unsigned int baud,
-                                        unsigned int *frac)
-{
-       struct uart_port *port = &up->port;
-       unsigned int quot_16;
-
-       quot_16 = DIV_ROUND_CLOSEST(port->uartclk, baud);
-       *frac = quot_16 & 0x0f;
-
-       return quot_16 >> 4;
-}
-
-static unsigned int serial8250_get_divisor(struct uart_8250_port *up,
-                                          unsigned int baud,
-                                          unsigned int *frac)
-{
-       struct uart_port *port = &up->port;
-       unsigned int quot;
-
-       /*
-        * Handle magic divisors for baud rates above baud_base on
-        * SMSC SuperIO chips.
-        *
-        */
-       if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
-           baud == (port->uartclk/4))
-               quot = 0x8001;
-       else if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
-                baud == (port->uartclk/8))
-               quot = 0x8002;
-       else if (up->port.type == PORT_XR17V35X)
-               quot = xr17v35x_get_divisor(up, baud, frac);
-       else
-               quot = uart_get_divisor(port, baud);
-
-       /*
-        * Oxford Semi 952 rev B workaround
-        */
-       if (up->bugs & UART_BUG_QUOT && (quot & 0xff) == 0)
-               quot++;
-
-       return quot;
-}
-
-static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
-                                           tcflag_t c_cflag)
-{
-       unsigned char cval;
-
-       switch (c_cflag & CSIZE) {
-       case CS5:
-               cval = UART_LCR_WLEN5;
-               break;
-       case CS6:
-               cval = UART_LCR_WLEN6;
-               break;
-       case CS7:
-               cval = UART_LCR_WLEN7;
-               break;
-       default:
-       case CS8:
-               cval = UART_LCR_WLEN8;
-               break;
-       }
-
-       if (c_cflag & CSTOPB)
-               cval |= UART_LCR_STOP;
-       if (c_cflag & PARENB) {
-               cval |= UART_LCR_PARITY;
-               if (up->bugs & UART_BUG_PARITY)
-                       up->fifo_bug = true;
-       }
-       if (!(c_cflag & PARODD))
-               cval |= UART_LCR_EPAR;
-#ifdef CMSPAR
-       if (c_cflag & CMSPAR)
-               cval |= UART_LCR_SPAR;
-#endif
-
-       return cval;
-}
-
-static void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
-                           unsigned int quot, unsigned int quot_frac)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-
-       /* Workaround to enable 115200 baud on OMAP1510 internal ports */
-       if (is_omap1510_8250(up)) {
-               if (baud == 115200) {
-                       quot = 1;
-                       serial_port_out(port, UART_OMAP_OSC_12M_SEL, 1);
-               } else
-                       serial_port_out(port, UART_OMAP_OSC_12M_SEL, 0);
-       }
-
-       /*
-        * For NatSemi, switch to bank 2 not bank 1, to avoid resetting EXCR2,
-        * otherwise just set DLAB
-        */
-       if (up->capabilities & UART_NATSEMI)
-               serial_port_out(port, UART_LCR, 0xe0);
-       else
-               serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
-
-       serial_dl_write(up, quot);
-
-       /* XR17V35x UARTs have an extra fractional divisor register (DLD) */
-       if (up->port.type == PORT_XR17V35X)
-               serial_port_out(port, 0x2, quot_frac);
-}
-
-void
-serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
-                         struct ktermios *old)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       unsigned char cval;
-       unsigned long flags;
-       unsigned int baud, quot, frac = 0;
-
-       cval = serial8250_compute_lcr(up, termios->c_cflag);
-
-       /*
-        * Ask the core to calculate the divisor for us.
-        */
-       baud = uart_get_baud_rate(port, termios, old,
-                                 port->uartclk / 16 / 0xffff,
-                                 port->uartclk / 16);
-       quot = serial8250_get_divisor(up, baud, &frac);
-
-       /*
-        * Ok, we're now changing the port state.  Do it with
-        * interrupts disabled.
-        */
-       serial8250_rpm_get(up);
-       spin_lock_irqsave(&port->lock, flags);
-
-       up->lcr = cval;                                 /* Save computed LCR */
-
-       if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
-               /* NOTE: If fifo_bug is not set, a user can set RX_trigger. */
-               if ((baud < 2400 && !up->dma) || up->fifo_bug) {
-                       up->fcr &= ~UART_FCR_TRIGGER_MASK;
-                       up->fcr |= UART_FCR_TRIGGER_1;
-               }
-       }
-
-       /*
-        * MCR-based auto flow control.  When AFE is enabled, RTS will be
-        * deasserted when the receive FIFO contains more characters than
-        * the trigger, or the MCR RTS bit is cleared.  In the case where
-        * the remote UART is not using CTS auto flow control, we must
-        * have sufficient FIFO entries for the latency of the remote
-        * UART to respond.  IOW, at least 32 bytes of FIFO.
-        */
-       if (up->capabilities & UART_CAP_AFE && port->fifosize >= 32) {
-               up->mcr &= ~UART_MCR_AFE;
-               if (termios->c_cflag & CRTSCTS)
-                       up->mcr |= UART_MCR_AFE;
-       }
-
-       /*
-        * Update the per-port timeout.
-        */
-       uart_update_timeout(port, termios->c_cflag, baud);
-
-       port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
-       if (termios->c_iflag & INPCK)
-               port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
-       if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
-               port->read_status_mask |= UART_LSR_BI;
-
-       /*
-        * Characteres to ignore
-        */
-       port->ignore_status_mask = 0;
-       if (termios->c_iflag & IGNPAR)
-               port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
-       if (termios->c_iflag & IGNBRK) {
-               port->ignore_status_mask |= UART_LSR_BI;
-               /*
-                * If we're ignoring parity and break indicators,
-                * ignore overruns too (for real raw support).
-                */
-               if (termios->c_iflag & IGNPAR)
-                       port->ignore_status_mask |= UART_LSR_OE;
-       }
-
-       /*
-        * ignore all characters if CREAD is not set
-        */
-       if ((termios->c_cflag & CREAD) == 0)
-               port->ignore_status_mask |= UART_LSR_DR;
-
-       /*
-        * CTS flow control flag and modem status interrupts
-        */
-       up->ier &= ~UART_IER_MSI;
-       if (!(up->bugs & UART_BUG_NOMSR) &&
-                       UART_ENABLE_MS(&up->port, termios->c_cflag))
-               up->ier |= UART_IER_MSI;
-       if (up->capabilities & UART_CAP_UUE)
-               up->ier |= UART_IER_UUE;
-       if (up->capabilities & UART_CAP_RTOIE)
-               up->ier |= UART_IER_RTOIE;
-
-       serial_port_out(port, UART_IER, up->ier);
-
-       if (up->capabilities & UART_CAP_EFR) {
-               unsigned char efr = 0;
-               /*
-                * TI16C752/Startech hardware flow control.  FIXME:
-                * - TI16C752 requires control thresholds to be set.
-                * - UART_MCR_RTS is ineffective if auto-RTS mode is enabled.
-                */
-               if (termios->c_cflag & CRTSCTS)
-                       efr |= UART_EFR_CTS;
-
-               serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
-               if (port->flags & UPF_EXAR_EFR)
-                       serial_port_out(port, UART_XR_EFR, efr);
-               else
-                       serial_port_out(port, UART_EFR, efr);
-       }
-
-       serial8250_set_divisor(port, baud, quot, frac);
+       spin_lock_irqsave(&up->port.lock, flags);
 
        /*
-        * LCR DLAB must be set to enable 64-byte FIFO mode. If the FCR
-        * is written without DLAB set, this mode will be disabled.
+        * Must disable interrupts or else we risk racing with the interrupt
+        * based handler.
         */
-       if (port->type == PORT_16750)
-               serial_port_out(port, UART_FCR, up->fcr);
-
-       serial_port_out(port, UART_LCR, up->lcr);       /* reset DLAB */
-       if (port->type != PORT_16750) {
-               /* emulated UARTs (Lucent Venus 167x) need two steps */
-               if (up->fcr & UART_FCR_ENABLE_FIFO)
-                       serial_port_out(port, UART_FCR, UART_FCR_ENABLE_FIFO);
-               serial_port_out(port, UART_FCR, up->fcr);       /* set fcr */
-       }
-       serial8250_set_mctrl(port, port->mctrl);
-       spin_unlock_irqrestore(&port->lock, flags);
-       serial8250_rpm_put(up);
-
-       /* Don't rewrite B0 */
-       if (tty_termios_baud_rate(termios))
-               tty_termios_encode_baud_rate(termios, baud, baud);
-}
-EXPORT_SYMBOL(serial8250_do_set_termios);
-
-static void
-serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
-                      struct ktermios *old)
-{
-       if (port->set_termios)
-               port->set_termios(port, termios, old);
-       else
-               serial8250_do_set_termios(port, termios, old);
-}
-
-static void
-serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios)
-{
-       if (termios->c_line == N_PPS) {
-               port->flags |= UPF_HARDPPS_CD;
-               spin_lock_irq(&port->lock);
-               serial8250_enable_ms(port);
-               spin_unlock_irq(&port->lock);
-       } else {
-               port->flags &= ~UPF_HARDPPS_CD;
-               if (!UART_ENABLE_MS(port, termios->c_cflag)) {
-                       spin_lock_irq(&port->lock);
-                       serial8250_disable_ms(port);
-                       spin_unlock_irq(&port->lock);
-               }
+       if (up->port.irq) {
+               ier = serial_in(up, UART_IER);
+               serial_out(up, UART_IER, 0);
        }
-}
 
+       iir = serial_in(up, UART_IIR);
 
-void serial8250_do_pm(struct uart_port *port, unsigned int state,
-                     unsigned int oldstate)
-{
-       struct uart_8250_port *p = up_to_u8250p(port);
+       /*
+        * This should be a safe test for anyone who doesn't trust the
+        * IIR bits on their UART, but it's specifically designed for
+        * the "Diva" UART used on the management processor on many HP
+        * ia64 and parisc boxes.
+        */
+       lsr = serial_in(up, UART_LSR);
+       up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+       if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
+           (!uart_circ_empty(&up->port.state->xmit) || up->port.x_char) &&
+           (lsr & UART_LSR_THRE)) {
+               iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
+               iir |= UART_IIR_THRI;
+       }
 
-       serial8250_set_sleep(p, state != 0);
-}
-EXPORT_SYMBOL(serial8250_do_pm);
+       if (!(iir & UART_IIR_NO_INT))
+               serial8250_tx_chars(up);
 
-static void
-serial8250_pm(struct uart_port *port, unsigned int state,
-             unsigned int oldstate)
-{
-       if (port->pm)
-               port->pm(port, state, oldstate);
-       else
-               serial8250_do_pm(port, state, oldstate);
-}
+       if (up->port.irq)
+               serial_out(up, UART_IER, ier);
 
-static unsigned int serial8250_port_size(struct uart_8250_port *pt)
-{
-       if (pt->port.mapsize)
-               return pt->port.mapsize;
-       if (pt->port.iotype == UPIO_AU) {
-               if (pt->port.type == PORT_RT2880)
-                       return 0x100;
-               return 0x1000;
-       }
-       if (is_omap1_8250(pt))
-               return 0x16 << pt->port.regshift;
+       spin_unlock_irqrestore(&up->port.lock, flags);
 
-       return 8 << pt->port.regshift;
+       /* Standard timer interval plus 0.2s to keep the port running */
+       mod_timer(&up->timer,
+               jiffies + uart_poll_timeout(&up->port) + HZ / 5);
 }
 
-/*
- * Resource handling.
- */
-static int serial8250_request_std_resource(struct uart_8250_port *up)
+static int univ8250_setup_irq(struct uart_8250_port *up)
 {
-       unsigned int size = serial8250_port_size(up);
        struct uart_port *port = &up->port;
-       int ret = 0;
+       int retval = 0;
 
-       switch (port->iotype) {
-       case UPIO_AU:
-       case UPIO_TSI:
-       case UPIO_MEM32:
-       case UPIO_MEM32BE:
-       case UPIO_MEM:
-               if (!port->mapbase)
-                       break;
+       /*
+        * The above check will only give an accurate result the first time
+        * the port is opened so this value needs to be preserved.
+        */
+       if (up->bugs & UART_BUG_THRE) {
+               pr_debug("ttyS%d - using backup timer\n", serial_index(port));
 
-               if (!request_mem_region(port->mapbase, size, "serial")) {
-                       ret = -EBUSY;
-                       break;
-               }
+               up->timer.function = serial8250_backup_timeout;
+               up->timer.data = (unsigned long)up;
+               mod_timer(&up->timer, jiffies +
+                         uart_poll_timeout(port) + HZ / 5);
+       }
 
-               if (port->flags & UPF_IOREMAP) {
-                       port->membase = ioremap_nocache(port->mapbase, size);
-                       if (!port->membase) {
-                               release_mem_region(port->mapbase, size);
-                               ret = -ENOMEM;
-                       }
-               }
-               break;
+       /*
+        * If the "interrupt" for this port doesn't correspond with any
+        * hardware interrupt, we use a timer-based system.  The original
+        * driver used to do this with IRQ0.
+        */
+       if (!port->irq) {
+               up->timer.data = (unsigned long)up;
+               mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
+       } else
+               retval = serial_link_irq_chain(up);
 
-       case UPIO_HUB6:
-       case UPIO_PORT:
-               if (!request_region(port->iobase, size, "serial"))
-                       ret = -EBUSY;
-               break;
-       }
-       return ret;
+       return retval;
 }
 
-static void serial8250_release_std_resource(struct uart_8250_port *up)
+static void univ8250_release_irq(struct uart_8250_port *up)
 {
-       unsigned int size = serial8250_port_size(up);
        struct uart_port *port = &up->port;
 
-       switch (port->iotype) {
-       case UPIO_AU:
-       case UPIO_TSI:
-       case UPIO_MEM32:
-       case UPIO_MEM32BE:
-       case UPIO_MEM:
-               if (!port->mapbase)
-                       break;
-
-               if (port->flags & UPF_IOREMAP) {
-                       iounmap(port->membase);
-                       port->membase = NULL;
-               }
-
-               release_mem_region(port->mapbase, size);
-               break;
-
-       case UPIO_HUB6:
-       case UPIO_PORT:
-               release_region(port->iobase, size);
-               break;
-       }
+       del_timer_sync(&up->timer);
+       up->timer.function = serial8250_timeout;
+       if (port->irq)
+               serial_unlink_irq_chain(up);
 }
 
 #ifdef CONFIG_SERIAL_8250_RSA
@@ -2848,259 +396,6 @@ static void serial8250_release_rsa_resource(struct uart_8250_port *up)
 }
 #endif
 
-static void serial8250_release_port(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-
-       serial8250_release_std_resource(up);
-}
-
-static int serial8250_request_port(struct uart_port *port)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       int ret;
-
-       if (port->type == PORT_8250_CIR)
-               return -ENODEV;
-
-       ret = serial8250_request_std_resource(up);
-
-       return ret;
-}
-
-static int fcr_get_rxtrig_bytes(struct uart_8250_port *up)
-{
-       const struct serial8250_config *conf_type = &uart_config[up->port.type];
-       unsigned char bytes;
-
-       bytes = conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(up->fcr)];
-
-       return bytes ? bytes : -EOPNOTSUPP;
-}
-
-static int bytes_to_fcr_rxtrig(struct uart_8250_port *up, unsigned char bytes)
-{
-       const struct serial8250_config *conf_type = &uart_config[up->port.type];
-       int i;
-
-       if (!conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(UART_FCR_R_TRIG_00)])
-               return -EOPNOTSUPP;
-
-       for (i = 1; i < UART_FCR_R_TRIG_MAX_STATE; i++) {
-               if (bytes < conf_type->rxtrig_bytes[i])
-                       /* Use the nearest lower value */
-                       return (--i) << UART_FCR_R_TRIG_SHIFT;
-       }
-
-       return UART_FCR_R_TRIG_11;
-}
-
-static int do_get_rxtrig(struct tty_port *port)
-{
-       struct uart_state *state = container_of(port, struct uart_state, port);
-       struct uart_port *uport = state->uart_port;
-       struct uart_8250_port *up =
-               container_of(uport, struct uart_8250_port, port);
-
-       if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1)
-               return -EINVAL;
-
-       return fcr_get_rxtrig_bytes(up);
-}
-
-static int do_serial8250_get_rxtrig(struct tty_port *port)
-{
-       int rxtrig_bytes;
-
-       mutex_lock(&port->mutex);
-       rxtrig_bytes = do_get_rxtrig(port);
-       mutex_unlock(&port->mutex);
-
-       return rxtrig_bytes;
-}
-
-static ssize_t serial8250_get_attr_rx_trig_bytes(struct device *dev,
-       struct device_attribute *attr, char *buf)
-{
-       struct tty_port *port = dev_get_drvdata(dev);
-       int rxtrig_bytes;
-
-       rxtrig_bytes = do_serial8250_get_rxtrig(port);
-       if (rxtrig_bytes < 0)
-               return rxtrig_bytes;
-
-       return snprintf(buf, PAGE_SIZE, "%d\n", rxtrig_bytes);
-}
-
-static int do_set_rxtrig(struct tty_port *port, unsigned char bytes)
-{
-       struct uart_state *state = container_of(port, struct uart_state, port);
-       struct uart_port *uport = state->uart_port;
-       struct uart_8250_port *up =
-               container_of(uport, struct uart_8250_port, port);
-       int rxtrig;
-
-       if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1 ||
-           up->fifo_bug)
-               return -EINVAL;
-
-       rxtrig = bytes_to_fcr_rxtrig(up, bytes);
-       if (rxtrig < 0)
-               return rxtrig;
-
-       serial8250_clear_fifos(up);
-       up->fcr &= ~UART_FCR_TRIGGER_MASK;
-       up->fcr |= (unsigned char)rxtrig;
-       serial_out(up, UART_FCR, up->fcr);
-       return 0;
-}
-
-static int do_serial8250_set_rxtrig(struct tty_port *port, unsigned char bytes)
-{
-       int ret;
-
-       mutex_lock(&port->mutex);
-       ret = do_set_rxtrig(port, bytes);
-       mutex_unlock(&port->mutex);
-
-       return ret;
-}
-
-static ssize_t serial8250_set_attr_rx_trig_bytes(struct device *dev,
-       struct device_attribute *attr, const char *buf, size_t count)
-{
-       struct tty_port *port = dev_get_drvdata(dev);
-       unsigned char bytes;
-       int ret;
-
-       if (!count)
-               return -EINVAL;
-
-       ret = kstrtou8(buf, 10, &bytes);
-       if (ret < 0)
-               return ret;
-
-       ret = do_serial8250_set_rxtrig(port, bytes);
-       if (ret < 0)
-               return ret;
-
-       return count;
-}
-
-static DEVICE_ATTR(rx_trig_bytes, S_IRUSR | S_IWUSR | S_IRGRP,
-                  serial8250_get_attr_rx_trig_bytes,
-                  serial8250_set_attr_rx_trig_bytes);
-
-static struct attribute *serial8250_dev_attrs[] = {
-       &dev_attr_rx_trig_bytes.attr,
-       NULL,
-       };
-
-static struct attribute_group serial8250_dev_attr_group = {
-       .attrs = serial8250_dev_attrs,
-       };
-
-static void register_dev_spec_attr_grp(struct uart_8250_port *up)
-{
-       const struct serial8250_config *conf_type = &uart_config[up->port.type];
-
-       if (conf_type->rxtrig_bytes[0])
-               up->port.attr_group = &serial8250_dev_attr_group;
-}
-
-static void serial8250_config_port(struct uart_port *port, int flags)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-       int ret;
-
-       if (port->type == PORT_8250_CIR)
-               return;
-
-       /*
-        * Find the region that we can probe for.  This in turn
-        * tells us whether we can probe for the type of port.
-        */
-       ret = serial8250_request_std_resource(up);
-       if (ret < 0)
-               return;
-
-       if (port->iotype != up->cur_iotype)
-               set_io_from_upio(port);
-
-       if (flags & UART_CONFIG_TYPE)
-               autoconfig(up);
-
-       /* if access method is AU, it is a 16550 with a quirk */
-       if (port->type == PORT_16550A && port->iotype == UPIO_AU)
-               up->bugs |= UART_BUG_NOMSR;
-
-       /* HW bugs may trigger IRQ while IIR == NO_INT */
-       if (port->type == PORT_TEGRA)
-               up->bugs |= UART_BUG_NOMSR;
-
-       if (port->type != PORT_UNKNOWN && flags & UART_CONFIG_IRQ)
-               autoconfig_irq(up);
-
-       if (port->type == PORT_UNKNOWN)
-               serial8250_release_std_resource(up);
-
-       /* Fixme: probably not the best place for this */
-       if ((port->type == PORT_XR17V35X) ||
-          (port->type == PORT_XR17D15X))
-               port->handle_irq = exar_handle_irq;
-
-       register_dev_spec_attr_grp(up);
-       up->fcr = uart_config[up->port.type].fcr;
-}
-
-static int
-serial8250_verify_port(struct uart_port *port, struct serial_struct *ser)
-{
-       if (ser->irq >= nr_irqs || ser->irq < 0 ||
-           ser->baud_base < 9600 || ser->type < PORT_UNKNOWN ||
-           ser->type >= ARRAY_SIZE(uart_config) || ser->type == PORT_CIRRUS ||
-           ser->type == PORT_STARTECH)
-               return -EINVAL;
-       return 0;
-}
-
-static const char *
-serial8250_type(struct uart_port *port)
-{
-       int type = port->type;
-
-       if (type >= ARRAY_SIZE(uart_config))
-               type = 0;
-       return uart_config[type].name;
-}
-
-static const struct uart_ops serial8250_pops = {
-       .tx_empty       = serial8250_tx_empty,
-       .set_mctrl      = serial8250_set_mctrl,
-       .get_mctrl      = serial8250_get_mctrl,
-       .stop_tx        = serial8250_stop_tx,
-       .start_tx       = serial8250_start_tx,
-       .throttle       = serial8250_throttle,
-       .unthrottle     = serial8250_unthrottle,
-       .stop_rx        = serial8250_stop_rx,
-       .enable_ms      = serial8250_enable_ms,
-       .break_ctl      = serial8250_break_ctl,
-       .startup        = serial8250_startup,
-       .shutdown       = serial8250_shutdown,
-       .set_termios    = serial8250_set_termios,
-       .set_ldisc      = serial8250_set_ldisc,
-       .pm             = serial8250_pm,
-       .type           = serial8250_type,
-       .release_port   = serial8250_release_port,
-       .request_port   = serial8250_request_port,
-       .config_port    = serial8250_config_port,
-       .verify_port    = serial8250_verify_port,
-#ifdef CONFIG_CONSOLE_POLL
-       .poll_get_char = serial8250_get_poll_char,
-       .poll_put_char = serial8250_put_poll_char,
-#endif
-};
-
 static const struct uart_ops *base_ops;
 static struct uart_ops univ8250_port_ops;
 
@@ -3139,42 +434,6 @@ void serial8250_set_isa_configurator(
 }
 EXPORT_SYMBOL(serial8250_set_isa_configurator);
 
-static void serial8250_init_port(struct uart_8250_port *up)
-{
-       struct uart_port *port = &up->port;
-
-       spin_lock_init(&port->lock);
-       port->ops = &serial8250_pops;
-
-       up->cur_iotype = 0xFF;
-}
-
-static void serial8250_set_defaults(struct uart_8250_port *up)
-{
-       struct uart_port *port = &up->port;
-
-       if (up->port.flags & UPF_FIXED_TYPE) {
-               unsigned int type = up->port.type;
-
-               if (!up->port.fifosize)
-                       up->port.fifosize = uart_config[type].fifo_size;
-               if (!up->tx_loadsz)
-                       up->tx_loadsz = uart_config[type].tx_loadsz;
-               if (!up->capabilities)
-                       up->capabilities = uart_config[type].flags;
-       }
-
-       set_io_from_upio(port);
-
-       /* default dma handlers */
-       if (up->dma) {
-               if (!up->dma->tx_dma)
-                       up->dma->tx_dma = serial8250_tx_dma;
-               if (!up->dma->rx_dma)
-                       up->dma->rx_dma = serial8250_rx_dma;
-       }
-}
-
 #ifdef CONFIG_SERIAL_8250_RSA
 
 static void univ8250_config_port(struct uart_port *port, int flags)
@@ -3324,94 +583,6 @@ serial8250_register_ports(struct uart_driver *drv, struct device *dev)
 
 #ifdef CONFIG_SERIAL_8250_CONSOLE
 
-static void serial8250_console_putchar(struct uart_port *port, int ch)
-{
-       struct uart_8250_port *up = up_to_u8250p(port);
-
-       wait_for_xmitr(up, UART_LSR_THRE);
-       serial_port_out(port, UART_TX, ch);
-}
-
-/*
- *     Print a string to the serial port trying not to disturb
- *     any possible real use of the port...
- *
- *     The console_lock must be held when we get here.
- */
-static void serial8250_console_write(struct uart_8250_port *up, const char *s,
-                                    unsigned int count)
-{
-       struct uart_port *port = &up->port;
-       unsigned long flags;
-       unsigned int ier;
-       int locked = 1;
-
-       touch_nmi_watchdog();
-
-       serial8250_rpm_get(up);
-
-       if (port->sysrq)
-               locked = 0;
-       else if (oops_in_progress)
-               locked = spin_trylock_irqsave(&port->lock, flags);
-       else
-               spin_lock_irqsave(&port->lock, flags);
-
-       /*
-        *      First save the IER then disable the interrupts
-        */
-       ier = serial_port_in(port, UART_IER);
-
-       if (up->capabilities & UART_CAP_UUE)
-               serial_port_out(port, UART_IER, UART_IER_UUE);
-       else
-               serial_port_out(port, UART_IER, 0);
-
-       /* check scratch reg to see if port powered off during system sleep */
-       if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) {
-               struct ktermios termios;
-               unsigned int baud, quot, frac = 0;
-
-               termios.c_cflag = port->cons->cflag;
-               if (port->state->port.tty && termios.c_cflag == 0)
-                       termios.c_cflag = port->state->port.tty->termios.c_cflag;
-
-               baud = uart_get_baud_rate(port, &termios, NULL,
-                                         port->uartclk / 16 / 0xffff,
-                                         port->uartclk / 16);
-               quot = serial8250_get_divisor(up, baud, &frac);
-
-               serial8250_set_divisor(port, baud, quot, frac);
-               serial_port_out(port, UART_LCR, up->lcr);
-               serial_port_out(port, UART_MCR, UART_MCR_DTR | UART_MCR_RTS);
-
-               up->canary = 0;
-       }
-
-       uart_console_write(port, s, count, serial8250_console_putchar);
-
-       /*
-        *      Finally, wait for transmitter to become empty
-        *      and restore the IER
-        */
-       wait_for_xmitr(up, BOTH_EMPTY);
-       serial_port_out(port, UART_IER, ier);
-
-       /*
-        *      The receive handling will happen properly because the
-        *      receive ready bit will still be set; it is not cleared
-        *      on read.  However, modem control will not, we must
-        *      call it if we have saved something in the saved flags
-        *      while processing with interrupts off.
-        */
-       if (up->msr_saved_flags)
-               serial8250_modem_status(up);
-
-       if (locked)
-               spin_unlock_irqrestore(&port->lock, flags);
-       serial8250_rpm_put(up);
-}
-
 static void univ8250_console_write(struct console *co, const char *s,
                                   unsigned int count)
 {
@@ -3420,39 +591,6 @@ static void univ8250_console_write(struct console *co, const char *s,
        serial8250_console_write(up, s, count);
 }
 
-static unsigned int probe_baud(struct uart_port *port)
-{
-       unsigned char lcr, dll, dlm;
-       unsigned int quot;
-
-       lcr = serial_port_in(port, UART_LCR);
-       serial_port_out(port, UART_LCR, lcr | UART_LCR_DLAB);
-       dll = serial_port_in(port, UART_DLL);
-       dlm = serial_port_in(port, UART_DLM);
-       serial_port_out(port, UART_LCR, lcr);
-
-       quot = (dlm << 8) | dll;
-       return (port->uartclk / 16) / quot;
-}
-
-static int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
-{
-       int baud = 9600;
-       int bits = 8;
-       int parity = 'n';
-       int flow = 'n';
-
-       if (!port->iobase && !port->membase)
-               return -ENODEV;
-
-       if (options)
-               uart_parse_options(options, &baud, &parity, &bits, &flow);
-       else if (probe)
-               baud = probe_baud(port);
-
-       return uart_set_options(port, port->cons, baud, parity, bits, flow);
-}
-
 static int univ8250_console_setup(struct console *co, char *options)
 {
        struct uart_port *port;
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
new file mode 100644 (file)
index 0000000..4dc143e
--- /dev/null
@@ -0,0 +1,2898 @@
+/*
+ *  Base port operations for 8250/16550-type serial ports
+ *
+ *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
+ *  Split from 8250_core.c, Copyright (C) 2001 Russell King.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * A note about mapbase / membase
+ *
+ *  mapbase is the physical address of the IO port.
+ *  membase is an 'ioremapped' cookie.
+ */
+
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/tty.h>
+#include <linux/ratelimit.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/serial_8250.h>
+#include <linux/nmi.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/pm_runtime.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include "8250.h"
+
+/*
+ * Debugging.
+ */
+#if 0
+#define DEBUG_AUTOCONF(fmt...) printk(fmt)
+#else
+#define DEBUG_AUTOCONF(fmt...) do { } while (0)
+#endif
+
+#define BOTH_EMPTY     (UART_LSR_TEMT | UART_LSR_THRE)
+
+/*
+ * Here we define the default xmit fifo size used for each type of UART.
+ */
+static const struct serial8250_config uart_config[] = {
+       [PORT_UNKNOWN] = {
+               .name           = "unknown",
+               .fifo_size      = 1,
+               .tx_loadsz      = 1,
+       },
+       [PORT_8250] = {
+               .name           = "8250",
+               .fifo_size      = 1,
+               .tx_loadsz      = 1,
+       },
+       [PORT_16450] = {
+               .name           = "16450",
+               .fifo_size      = 1,
+               .tx_loadsz      = 1,
+       },
+       [PORT_16550] = {
+               .name           = "16550",
+               .fifo_size      = 1,
+               .tx_loadsz      = 1,
+       },
+       [PORT_16550A] = {
+               .name           = "16550A",
+               .fifo_size      = 16,
+               .tx_loadsz      = 16,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .rxtrig_bytes   = {1, 4, 8, 14},
+               .flags          = UART_CAP_FIFO,
+       },
+       [PORT_CIRRUS] = {
+               .name           = "Cirrus",
+               .fifo_size      = 1,
+               .tx_loadsz      = 1,
+       },
+       [PORT_16650] = {
+               .name           = "ST16650",
+               .fifo_size      = 1,
+               .tx_loadsz      = 1,
+               .flags          = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
+       },
+       [PORT_16650V2] = {
+               .name           = "ST16650V2",
+               .fifo_size      = 32,
+               .tx_loadsz      = 16,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
+                                 UART_FCR_T_TRIG_00,
+               .rxtrig_bytes   = {8, 16, 24, 28},
+               .flags          = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
+       },
+       [PORT_16750] = {
+               .name           = "TI16750",
+               .fifo_size      = 64,
+               .tx_loadsz      = 64,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
+                                 UART_FCR7_64BYTE,
+               .rxtrig_bytes   = {1, 16, 32, 56},
+               .flags          = UART_CAP_FIFO | UART_CAP_SLEEP | UART_CAP_AFE,
+       },
+       [PORT_STARTECH] = {
+               .name           = "Startech",
+               .fifo_size      = 1,
+               .tx_loadsz      = 1,
+       },
+       [PORT_16C950] = {
+               .name           = "16C950/954",
+               .fifo_size      = 128,
+               .tx_loadsz      = 128,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               /* UART_CAP_EFR breaks billionon CF bluetooth card. */
+               .flags          = UART_CAP_FIFO | UART_CAP_SLEEP,
+       },
+       [PORT_16654] = {
+               .name           = "ST16654",
+               .fifo_size      = 64,
+               .tx_loadsz      = 32,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
+                                 UART_FCR_T_TRIG_10,
+               .rxtrig_bytes   = {8, 16, 56, 60},
+               .flags          = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
+       },
+       [PORT_16850] = {
+               .name           = "XR16850",
+               .fifo_size      = 128,
+               .tx_loadsz      = 128,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .flags          = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
+       },
+       [PORT_RSA] = {
+               .name           = "RSA",
+               .fifo_size      = 2048,
+               .tx_loadsz      = 2048,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11,
+               .flags          = UART_CAP_FIFO,
+       },
+       [PORT_NS16550A] = {
+               .name           = "NS16550A",
+               .fifo_size      = 16,
+               .tx_loadsz      = 16,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .flags          = UART_CAP_FIFO | UART_NATSEMI,
+       },
+       [PORT_XSCALE] = {
+               .name           = "XScale",
+               .fifo_size      = 32,
+               .tx_loadsz      = 32,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .flags          = UART_CAP_FIFO | UART_CAP_UUE | UART_CAP_RTOIE,
+       },
+       [PORT_OCTEON] = {
+               .name           = "OCTEON",
+               .fifo_size      = 64,
+               .tx_loadsz      = 64,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .flags          = UART_CAP_FIFO,
+       },
+       [PORT_AR7] = {
+               .name           = "AR7",
+               .fifo_size      = 16,
+               .tx_loadsz      = 16,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00,
+               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
+       },
+       [PORT_U6_16550A] = {
+               .name           = "U6_16550A",
+               .fifo_size      = 64,
+               .tx_loadsz      = 64,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
+       },
+       [PORT_TEGRA] = {
+               .name           = "Tegra",
+               .fifo_size      = 32,
+               .tx_loadsz      = 8,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
+                                 UART_FCR_T_TRIG_01,
+               .rxtrig_bytes   = {1, 4, 8, 14},
+               .flags          = UART_CAP_FIFO | UART_CAP_RTOIE,
+       },
+       [PORT_XR17D15X] = {
+               .name           = "XR17D15X",
+               .fifo_size      = 64,
+               .tx_loadsz      = 64,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .flags          = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
+                                 UART_CAP_SLEEP,
+       },
+       [PORT_XR17V35X] = {
+               .name           = "XR17V35X",
+               .fifo_size      = 256,
+               .tx_loadsz      = 256,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11 |
+                                 UART_FCR_T_TRIG_11,
+               .flags          = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
+                                 UART_CAP_SLEEP,
+       },
+       [PORT_LPC3220] = {
+               .name           = "LPC3220",
+               .fifo_size      = 64,
+               .tx_loadsz      = 32,
+               .fcr            = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
+                                 UART_FCR_R_TRIG_00 | UART_FCR_T_TRIG_00,
+               .flags          = UART_CAP_FIFO,
+       },
+       [PORT_BRCM_TRUMANAGE] = {
+               .name           = "TruManage",
+               .fifo_size      = 1,
+               .tx_loadsz      = 1024,
+               .flags          = UART_CAP_HFIFO,
+       },
+       [PORT_8250_CIR] = {
+               .name           = "CIR port"
+       },
+       [PORT_ALTR_16550_F32] = {
+               .name           = "Altera 16550 FIFO32",
+               .fifo_size      = 32,
+               .tx_loadsz      = 32,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
+       },
+       [PORT_ALTR_16550_F64] = {
+               .name           = "Altera 16550 FIFO64",
+               .fifo_size      = 64,
+               .tx_loadsz      = 64,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
+       },
+       [PORT_ALTR_16550_F128] = {
+               .name           = "Altera 16550 FIFO128",
+               .fifo_size      = 128,
+               .tx_loadsz      = 128,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .flags          = UART_CAP_FIFO | UART_CAP_AFE,
+       },
+/* tx_loadsz is set to 63-bytes instead of 64-bytes to implement
+workaround of errata A-008006 which states that tx_loadsz should  be
+configured less than Maximum supported fifo bytes */
+       [PORT_16550A_FSL64] = {
+               .name           = "16550A_FSL64",
+               .fifo_size      = 64,
+               .tx_loadsz      = 63,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
+                                 UART_FCR7_64BYTE,
+               .flags          = UART_CAP_FIFO,
+       },
+};
+
+/* Uart divisor latch read */
+static int default_serial_dl_read(struct uart_8250_port *up)
+{
+       return serial_in(up, UART_DLL) | serial_in(up, UART_DLM) << 8;
+}
+
+/* Uart divisor latch write */
+static void default_serial_dl_write(struct uart_8250_port *up, int value)
+{
+       serial_out(up, UART_DLL, value & 0xff);
+       serial_out(up, UART_DLM, value >> 8 & 0xff);
+}
+
+#if defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_SERIAL_8250_RT288X)
+
+/* Au1x00/RT288x UART hardware has a weird register layout */
+static const s8 au_io_in_map[8] = {
+        0,     /* UART_RX  */
+        2,     /* UART_IER */
+        3,     /* UART_IIR */
+        5,     /* UART_LCR */
+        6,     /* UART_MCR */
+        7,     /* UART_LSR */
+        8,     /* UART_MSR */
+       -1,     /* UART_SCR (unmapped) */
+};
+
+static const s8 au_io_out_map[8] = {
+        1,     /* UART_TX  */
+        2,     /* UART_IER */
+        4,     /* UART_FCR */
+        5,     /* UART_LCR */
+        6,     /* UART_MCR */
+       -1,     /* UART_LSR (unmapped) */
+       -1,     /* UART_MSR (unmapped) */
+       -1,     /* UART_SCR (unmapped) */
+};
+
+static unsigned int au_serial_in(struct uart_port *p, int offset)
+{
+       if (offset >= ARRAY_SIZE(au_io_in_map))
+               return UINT_MAX;
+       offset = au_io_in_map[offset];
+       if (offset < 0)
+               return UINT_MAX;
+       return __raw_readl(p->membase + (offset << p->regshift));
+}
+
+static void au_serial_out(struct uart_port *p, int offset, int value)
+{
+       if (offset >= ARRAY_SIZE(au_io_out_map))
+               return;
+       offset = au_io_out_map[offset];
+       if (offset < 0)
+               return;
+       __raw_writel(value, p->membase + (offset << p->regshift));
+}
+
+/* Au1x00 haven't got a standard divisor latch */
+static int au_serial_dl_read(struct uart_8250_port *up)
+{
+       return __raw_readl(up->port.membase + 0x28);
+}
+
+static void au_serial_dl_write(struct uart_8250_port *up, int value)
+{
+       __raw_writel(value, up->port.membase + 0x28);
+}
+
+#endif
+
+static unsigned int hub6_serial_in(struct uart_port *p, int offset)
+{
+       offset = offset << p->regshift;
+       outb(p->hub6 - 1 + offset, p->iobase);
+       return inb(p->iobase + 1);
+}
+
+static void hub6_serial_out(struct uart_port *p, int offset, int value)
+{
+       offset = offset << p->regshift;
+       outb(p->hub6 - 1 + offset, p->iobase);
+       outb(value, p->iobase + 1);
+}
+
+static unsigned int mem_serial_in(struct uart_port *p, int offset)
+{
+       offset = offset << p->regshift;
+       return readb(p->membase + offset);
+}
+
+static void mem_serial_out(struct uart_port *p, int offset, int value)
+{
+       offset = offset << p->regshift;
+       writeb(value, p->membase + offset);
+}
+
+static void mem32_serial_out(struct uart_port *p, int offset, int value)
+{
+       offset = offset << p->regshift;
+       writel(value, p->membase + offset);
+}
+
+static unsigned int mem32_serial_in(struct uart_port *p, int offset)
+{
+       offset = offset << p->regshift;
+       return readl(p->membase + offset);
+}
+
+static void mem32be_serial_out(struct uart_port *p, int offset, int value)
+{
+       offset = offset << p->regshift;
+       iowrite32be(value, p->membase + offset);
+}
+
+static unsigned int mem32be_serial_in(struct uart_port *p, int offset)
+{
+       offset = offset << p->regshift;
+       return ioread32be(p->membase + offset);
+}
+
+static unsigned int io_serial_in(struct uart_port *p, int offset)
+{
+       offset = offset << p->regshift;
+       return inb(p->iobase + offset);
+}
+
+static void io_serial_out(struct uart_port *p, int offset, int value)
+{
+       offset = offset << p->regshift;
+       outb(value, p->iobase + offset);
+}
+
+static int serial8250_default_handle_irq(struct uart_port *port);
+static int exar_handle_irq(struct uart_port *port);
+
+static void set_io_from_upio(struct uart_port *p)
+{
+       struct uart_8250_port *up = up_to_u8250p(p);
+
+       up->dl_read = default_serial_dl_read;
+       up->dl_write = default_serial_dl_write;
+
+       switch (p->iotype) {
+       case UPIO_HUB6:
+               p->serial_in = hub6_serial_in;
+               p->serial_out = hub6_serial_out;
+               break;
+
+       case UPIO_MEM:
+               p->serial_in = mem_serial_in;
+               p->serial_out = mem_serial_out;
+               break;
+
+       case UPIO_MEM32:
+               p->serial_in = mem32_serial_in;
+               p->serial_out = mem32_serial_out;
+               break;
+
+       case UPIO_MEM32BE:
+               p->serial_in = mem32be_serial_in;
+               p->serial_out = mem32be_serial_out;
+               break;
+
+#if defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_SERIAL_8250_RT288X)
+       case UPIO_AU:
+               p->serial_in = au_serial_in;
+               p->serial_out = au_serial_out;
+               up->dl_read = au_serial_dl_read;
+               up->dl_write = au_serial_dl_write;
+               break;
+#endif
+
+       default:
+               p->serial_in = io_serial_in;
+               p->serial_out = io_serial_out;
+               break;
+       }
+       /* Remember loaded iotype */
+       up->cur_iotype = p->iotype;
+       p->handle_irq = serial8250_default_handle_irq;
+}
+
+static void
+serial_port_out_sync(struct uart_port *p, int offset, int value)
+{
+       switch (p->iotype) {
+       case UPIO_MEM:
+       case UPIO_MEM32:
+       case UPIO_MEM32BE:
+       case UPIO_AU:
+               p->serial_out(p, offset, value);
+               p->serial_in(p, UART_LCR);      /* safe, no side-effects */
+               break;
+       default:
+               p->serial_out(p, offset, value);
+       }
+}
+
+/*
+ * For the 16C950
+ */
+static void serial_icr_write(struct uart_8250_port *up, int offset, int value)
+{
+       serial_out(up, UART_SCR, offset);
+       serial_out(up, UART_ICR, value);
+}
+
+static unsigned int serial_icr_read(struct uart_8250_port *up, int offset)
+{
+       unsigned int value;
+
+       serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD);
+       serial_out(up, UART_SCR, offset);
+       value = serial_in(up, UART_ICR);
+       serial_icr_write(up, UART_ACR, up->acr);
+
+       return value;
+}
+
+/*
+ * FIFO support.
+ */
+static void serial8250_clear_fifos(struct uart_8250_port *p)
+{
+       if (p->capabilities & UART_CAP_FIFO) {
+               serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO);
+               serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO |
+                              UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+               serial_out(p, UART_FCR, 0);
+       }
+}
+
+void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p)
+{
+       serial8250_clear_fifos(p);
+       serial_out(p, UART_FCR, p->fcr);
+}
+EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos);
+
+void serial8250_rpm_get(struct uart_8250_port *p)
+{
+       if (!(p->capabilities & UART_CAP_RPM))
+               return;
+       pm_runtime_get_sync(p->port.dev);
+}
+EXPORT_SYMBOL_GPL(serial8250_rpm_get);
+
+void serial8250_rpm_put(struct uart_8250_port *p)
+{
+       if (!(p->capabilities & UART_CAP_RPM))
+               return;
+       pm_runtime_mark_last_busy(p->port.dev);
+       pm_runtime_put_autosuspend(p->port.dev);
+}
+EXPORT_SYMBOL_GPL(serial8250_rpm_put);
+
+/*
+ * These two wrappers ensure that enable_runtime_pm_tx() can be called more than
+ * once and disable_runtime_pm_tx() will still disable RPM because the fifo is
+ * empty and the HW can idle again.
+ */
+static void serial8250_rpm_get_tx(struct uart_8250_port *p)
+{
+       unsigned char rpm_active;
+
+       if (!(p->capabilities & UART_CAP_RPM))
+               return;
+
+       rpm_active = xchg(&p->rpm_tx_active, 1);
+       if (rpm_active)
+               return;
+       pm_runtime_get_sync(p->port.dev);
+}
+
+static void serial8250_rpm_put_tx(struct uart_8250_port *p)
+{
+       unsigned char rpm_active;
+
+       if (!(p->capabilities & UART_CAP_RPM))
+               return;
+
+       rpm_active = xchg(&p->rpm_tx_active, 0);
+       if (!rpm_active)
+               return;
+       pm_runtime_mark_last_busy(p->port.dev);
+       pm_runtime_put_autosuspend(p->port.dev);
+}
+
+/*
+ * IER sleep support.  UARTs which have EFRs need the "extended
+ * capability" bit enabled.  Note that on XR16C850s, we need to
+ * reset LCR to write to IER.
+ */
+static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
+{
+       unsigned char lcr = 0, efr = 0;
+       /*
+        * Exar UARTs have a SLEEP register that enables or disables
+        * each UART to enter sleep mode separately.  On the XR17V35x the
+        * register is accessible to each UART at the UART_EXAR_SLEEP
+        * offset but the UART channel may only write to the corresponding
+        * bit.
+        */
+       serial8250_rpm_get(p);
+       if ((p->port.type == PORT_XR17V35X) ||
+          (p->port.type == PORT_XR17D15X)) {
+               serial_out(p, UART_EXAR_SLEEP, sleep ? 0xff : 0);
+               goto out;
+       }
+
+       if (p->capabilities & UART_CAP_SLEEP) {
+               if (p->capabilities & UART_CAP_EFR) {
+                       lcr = serial_in(p, UART_LCR);
+                       efr = serial_in(p, UART_EFR);
+                       serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
+                       serial_out(p, UART_EFR, UART_EFR_ECB);
+                       serial_out(p, UART_LCR, 0);
+               }
+               serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
+               if (p->capabilities & UART_CAP_EFR) {
+                       serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
+                       serial_out(p, UART_EFR, efr);
+                       serial_out(p, UART_LCR, lcr);
+               }
+       }
+out:
+       serial8250_rpm_put(p);
+}
+
+#ifdef CONFIG_SERIAL_8250_RSA
+/*
+ * Attempts to turn on the RSA FIFO.  Returns zero on failure.
+ * We set the port uart clock rate if we succeed.
+ */
+static int __enable_rsa(struct uart_8250_port *up)
+{
+       unsigned char mode;
+       int result;
+
+       mode = serial_in(up, UART_RSA_MSR);
+       result = mode & UART_RSA_MSR_FIFO;
+
+       if (!result) {
+               serial_out(up, UART_RSA_MSR, mode | UART_RSA_MSR_FIFO);
+               mode = serial_in(up, UART_RSA_MSR);
+               result = mode & UART_RSA_MSR_FIFO;
+       }
+
+       if (result)
+               up->port.uartclk = SERIAL_RSA_BAUD_BASE * 16;
+
+       return result;
+}
+
+static void enable_rsa(struct uart_8250_port *up)
+{
+       if (up->port.type == PORT_RSA) {
+               if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
+                       spin_lock_irq(&up->port.lock);
+                       __enable_rsa(up);
+                       spin_unlock_irq(&up->port.lock);
+               }
+               if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
+                       serial_out(up, UART_RSA_FRR, 0);
+       }
+}
+
+/*
+ * Attempts to turn off the RSA FIFO.  Returns zero on failure.
+ * It is unknown why interrupts were disabled in here.  However,
+ * the caller is expected to preserve this behaviour by grabbing
+ * the spinlock before calling this function.
+ */
+static void disable_rsa(struct uart_8250_port *up)
+{
+       unsigned char mode;
+       int result;
+
+       if (up->port.type == PORT_RSA &&
+           up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) {
+               spin_lock_irq(&up->port.lock);
+
+               mode = serial_in(up, UART_RSA_MSR);
+               result = !(mode & UART_RSA_MSR_FIFO);
+
+               if (!result) {
+                       serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
+                       mode = serial_in(up, UART_RSA_MSR);
+                       result = !(mode & UART_RSA_MSR_FIFO);
+               }
+
+               if (result)
+                       up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
+               spin_unlock_irq(&up->port.lock);
+       }
+}
+#endif /* CONFIG_SERIAL_8250_RSA */
+
+/*
+ * This is a quickie test to see how big the FIFO is.
+ * It doesn't work at all the time, more's the pity.
+ */
+static int size_fifo(struct uart_8250_port *up)
+{
+       unsigned char old_fcr, old_mcr, old_lcr;
+       unsigned short old_dl;
+       int count;
+
+       old_lcr = serial_in(up, UART_LCR);
+       serial_out(up, UART_LCR, 0);
+       old_fcr = serial_in(up, UART_FCR);
+       old_mcr = serial_in(up, UART_MCR);
+       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
+                   UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+       serial_out(up, UART_MCR, UART_MCR_LOOP);
+       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
+       old_dl = serial_dl_read(up);
+       serial_dl_write(up, 0x0001);
+       serial_out(up, UART_LCR, 0x03);
+       for (count = 0; count < 256; count++)
+               serial_out(up, UART_TX, count);
+       mdelay(20);/* FIXME - schedule_timeout */
+       for (count = 0; (serial_in(up, UART_LSR) & UART_LSR_DR) &&
+            (count < 256); count++)
+               serial_in(up, UART_RX);
+       serial_out(up, UART_FCR, old_fcr);
+       serial_out(up, UART_MCR, old_mcr);
+       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
+       serial_dl_write(up, old_dl);
+       serial_out(up, UART_LCR, old_lcr);
+
+       return count;
+}
+
+/*
+ * Read UART ID using the divisor method - set DLL and DLM to zero
+ * and the revision will be in DLL and device type in DLM.  We
+ * preserve the device state across this.
+ */
+static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
+{
+       unsigned char old_dll, old_dlm, old_lcr;
+       unsigned int id;
+
+       old_lcr = serial_in(p, UART_LCR);
+       serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
+
+       old_dll = serial_in(p, UART_DLL);
+       old_dlm = serial_in(p, UART_DLM);
+
+       serial_out(p, UART_DLL, 0);
+       serial_out(p, UART_DLM, 0);
+
+       id = serial_in(p, UART_DLL) | serial_in(p, UART_DLM) << 8;
+
+       serial_out(p, UART_DLL, old_dll);
+       serial_out(p, UART_DLM, old_dlm);
+       serial_out(p, UART_LCR, old_lcr);
+
+       return id;
+}
+
+/*
+ * This is a helper routine to autodetect StarTech/Exar/Oxsemi UART's.
+ * When this function is called we know it is at least a StarTech
+ * 16650 V2, but it might be one of several StarTech UARTs, or one of
+ * its clones.  (We treat the broken original StarTech 16650 V1 as a
+ * 16550, and why not?  Startech doesn't seem to even acknowledge its
+ * existence.)
+ *
+ * What evil have men's minds wrought...
+ */
+static void autoconfig_has_efr(struct uart_8250_port *up)
+{
+       unsigned int id1, id2, id3, rev;
+
+       /*
+        * Everything with an EFR has SLEEP
+        */
+       up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
+
+       /*
+        * First we check to see if it's an Oxford Semiconductor UART.
+        *
+        * If we have to do this here because some non-National
+        * Semiconductor clone chips lock up if you try writing to the
+        * LSR register (which serial_icr_read does)
+        */
+
+       /*
+        * Check for Oxford Semiconductor 16C950.
+        *
+        * EFR [4] must be set else this test fails.
+        *
+        * This shouldn't be necessary, but Mike Hudson (Exoray@isys.ca)
+        * claims that it's needed for 952 dual UART's (which are not
+        * recommended for new designs).
+        */
+       up->acr = 0;
+       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+       serial_out(up, UART_EFR, UART_EFR_ECB);
+       serial_out(up, UART_LCR, 0x00);
+       id1 = serial_icr_read(up, UART_ID1);
+       id2 = serial_icr_read(up, UART_ID2);
+       id3 = serial_icr_read(up, UART_ID3);
+       rev = serial_icr_read(up, UART_REV);
+
+       DEBUG_AUTOCONF("950id=%02x:%02x:%02x:%02x ", id1, id2, id3, rev);
+
+       if (id1 == 0x16 && id2 == 0xC9 &&
+           (id3 == 0x50 || id3 == 0x52 || id3 == 0x54)) {
+               up->port.type = PORT_16C950;
+
+               /*
+                * Enable work around for the Oxford Semiconductor 952 rev B
+                * chip which causes it to seriously miscalculate baud rates
+                * when DLL is 0.
+                */
+               if (id3 == 0x52 && rev == 0x01)
+                       up->bugs |= UART_BUG_QUOT;
+               return;
+       }
+
+       /*
+        * We check for a XR16C850 by setting DLL and DLM to 0, and then
+        * reading back DLL and DLM.  The chip type depends on the DLM
+        * value read back:
+        *  0x10 - XR16C850 and the DLL contains the chip revision.
+        *  0x12 - XR16C2850.
+        *  0x14 - XR16C854.
+        */
+       id1 = autoconfig_read_divisor_id(up);
+       DEBUG_AUTOCONF("850id=%04x ", id1);
+
+       id2 = id1 >> 8;
+       if (id2 == 0x10 || id2 == 0x12 || id2 == 0x14) {
+               up->port.type = PORT_16850;
+               return;
+       }
+
+       /*
+        * It wasn't an XR16C850.
+        *
+        * We distinguish between the '654 and the '650 by counting
+        * how many bytes are in the FIFO.  I'm using this for now,
+        * since that's the technique that was sent to me in the
+        * serial driver update, but I'm not convinced this works.
+        * I've had problems doing this in the past.  -TYT
+        */
+       if (size_fifo(up) == 64)
+               up->port.type = PORT_16654;
+       else
+               up->port.type = PORT_16650V2;
+}
+
+/*
+ * We detected a chip without a FIFO.  Only two fall into
+ * this category - the original 8250 and the 16450.  The
+ * 16450 has a scratch register (accessible with LCR=0)
+ */
+static void autoconfig_8250(struct uart_8250_port *up)
+{
+       unsigned char scratch, status1, status2;
+
+       up->port.type = PORT_8250;
+
+       scratch = serial_in(up, UART_SCR);
+       serial_out(up, UART_SCR, 0xa5);
+       status1 = serial_in(up, UART_SCR);
+       serial_out(up, UART_SCR, 0x5a);
+       status2 = serial_in(up, UART_SCR);
+       serial_out(up, UART_SCR, scratch);
+
+       if (status1 == 0xa5 && status2 == 0x5a)
+               up->port.type = PORT_16450;
+}
+
+static int broken_efr(struct uart_8250_port *up)
+{
+       /*
+        * Exar ST16C2550 "A2" devices incorrectly detect as
+        * having an EFR, and report an ID of 0x0201.  See
+        * http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-11/4812.html
+        */
+       if (autoconfig_read_divisor_id(up) == 0x0201 && size_fifo(up) == 16)
+               return 1;
+
+       return 0;
+}
+
+/*
+ * We know that the chip has FIFOs.  Does it have an EFR?  The
+ * EFR is located in the same register position as the IIR and
+ * we know the top two bits of the IIR are currently set.  The
+ * EFR should contain zero.  Try to read the EFR.
+ */
+static void autoconfig_16550a(struct uart_8250_port *up)
+{
+       unsigned char status1, status2;
+       unsigned int iersave;
+
+       up->port.type = PORT_16550A;
+       up->capabilities |= UART_CAP_FIFO;
+
+       /*
+        * XR17V35x UARTs have an extra divisor register, DLD
+        * that gets enabled with when DLAB is set which will
+        * cause the device to incorrectly match and assign
+        * port type to PORT_16650.  The EFR for this UART is
+        * found at offset 0x09. Instead check the Deice ID (DVID)
+        * register for a 2, 4 or 8 port UART.
+        */
+       if (up->port.flags & UPF_EXAR_EFR) {
+               status1 = serial_in(up, UART_EXAR_DVID);
+               if (status1 == 0x82 || status1 == 0x84 || status1 == 0x88) {
+                       DEBUG_AUTOCONF("Exar XR17V35x ");
+                       up->port.type = PORT_XR17V35X;
+                       up->capabilities |= UART_CAP_AFE | UART_CAP_EFR |
+                                               UART_CAP_SLEEP;
+
+                       return;
+               }
+
+       }
+
+       /*
+        * Check for presence of the EFR when DLAB is set.
+        * Only ST16C650V1 UARTs pass this test.
+        */
+       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
+       if (serial_in(up, UART_EFR) == 0) {
+               serial_out(up, UART_EFR, 0xA8);
+               if (serial_in(up, UART_EFR) != 0) {
+                       DEBUG_AUTOCONF("EFRv1 ");
+                       up->port.type = PORT_16650;
+                       up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
+               } else {
+                       serial_out(up, UART_LCR, 0);
+                       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
+                                  UART_FCR7_64BYTE);
+                       status1 = serial_in(up, UART_IIR) >> 5;
+                       serial_out(up, UART_FCR, 0);
+                       serial_out(up, UART_LCR, 0);
+
+                       if (status1 == 7)
+                               up->port.type = PORT_16550A_FSL64;
+                       else
+                               DEBUG_AUTOCONF("Motorola 8xxx DUART ");
+               }
+               serial_out(up, UART_EFR, 0);
+               return;
+       }
+
+       /*
+        * Maybe it requires 0xbf to be written to the LCR.
+        * (other ST16C650V2 UARTs, TI16C752A, etc)
+        */
+       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+       if (serial_in(up, UART_EFR) == 0 && !broken_efr(up)) {
+               DEBUG_AUTOCONF("EFRv2 ");
+               autoconfig_has_efr(up);
+               return;
+       }
+
+       /*
+        * Check for a National Semiconductor SuperIO chip.
+        * Attempt to switch to bank 2, read the value of the LOOP bit
+        * from EXCR1. Switch back to bank 0, change it in MCR. Then
+        * switch back to bank 2, read it from EXCR1 again and check
+        * it's changed. If so, set baud_base in EXCR2 to 921600. -- dwmw2
+        */
+       serial_out(up, UART_LCR, 0);
+       status1 = serial_in(up, UART_MCR);
+       serial_out(up, UART_LCR, 0xE0);
+       status2 = serial_in(up, 0x02); /* EXCR1 */
+
+       if (!((status2 ^ status1) & UART_MCR_LOOP)) {
+               serial_out(up, UART_LCR, 0);
+               serial_out(up, UART_MCR, status1 ^ UART_MCR_LOOP);
+               serial_out(up, UART_LCR, 0xE0);
+               status2 = serial_in(up, 0x02); /* EXCR1 */
+               serial_out(up, UART_LCR, 0);
+               serial_out(up, UART_MCR, status1);
+
+               if ((status2 ^ status1) & UART_MCR_LOOP) {
+                       unsigned short quot;
+
+                       serial_out(up, UART_LCR, 0xE0);
+
+                       quot = serial_dl_read(up);
+                       quot <<= 3;
+
+                       if (ns16550a_goto_highspeed(up))
+                               serial_dl_write(up, quot);
+
+                       serial_out(up, UART_LCR, 0);
+
+                       up->port.uartclk = 921600*16;
+                       up->port.type = PORT_NS16550A;
+                       up->capabilities |= UART_NATSEMI;
+                       return;
+               }
+       }
+
+       /*
+        * No EFR.  Try to detect a TI16750, which only sets bit 5 of
+        * the IIR when 64 byte FIFO mode is enabled when DLAB is set.
+        * Try setting it with and without DLAB set.  Cheap clones
+        * set bit 5 without DLAB set.
+        */
+       serial_out(up, UART_LCR, 0);
+       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
+       status1 = serial_in(up, UART_IIR) >> 5;
+       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
+       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
+       status2 = serial_in(up, UART_IIR) >> 5;
+       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+       serial_out(up, UART_LCR, 0);
+
+       DEBUG_AUTOCONF("iir1=%d iir2=%d ", status1, status2);
+
+       if (status1 == 6 && status2 == 7) {
+               up->port.type = PORT_16750;
+               up->capabilities |= UART_CAP_AFE | UART_CAP_SLEEP;
+               return;
+       }
+
+       /*
+        * Try writing and reading the UART_IER_UUE bit (b6).
+        * If it works, this is probably one of the Xscale platform's
+        * internal UARTs.
+        * We're going to explicitly set the UUE bit to 0 before
+        * trying to write and read a 1 just to make sure it's not
+        * already a 1 and maybe locked there before we even start start.
+        */
+       iersave = serial_in(up, UART_IER);
+       serial_out(up, UART_IER, iersave & ~UART_IER_UUE);
+       if (!(serial_in(up, UART_IER) & UART_IER_UUE)) {
+               /*
+                * OK it's in a known zero state, try writing and reading
+                * without disturbing the current state of the other bits.
+                */
+               serial_out(up, UART_IER, iersave | UART_IER_UUE);
+               if (serial_in(up, UART_IER) & UART_IER_UUE) {
+                       /*
+                        * It's an Xscale.
+                        * We'll leave the UART_IER_UUE bit set to 1 (enabled).
+                        */
+                       DEBUG_AUTOCONF("Xscale ");
+                       up->port.type = PORT_XSCALE;
+                       up->capabilities |= UART_CAP_UUE | UART_CAP_RTOIE;
+                       return;
+               }
+       } else {
+               /*
+                * If we got here we couldn't force the IER_UUE bit to 0.
+                * Log it and continue.
+                */
+               DEBUG_AUTOCONF("Couldn't force IER_UUE to 0 ");
+       }
+       serial_out(up, UART_IER, iersave);
+
+       /*
+        * Exar uarts have EFR in a weird location
+        */
+       if (up->port.flags & UPF_EXAR_EFR) {
+               DEBUG_AUTOCONF("Exar XR17D15x ");
+               up->port.type = PORT_XR17D15X;
+               up->capabilities |= UART_CAP_AFE | UART_CAP_EFR |
+                                   UART_CAP_SLEEP;
+
+               return;
+       }
+
+       /*
+        * We distinguish between 16550A and U6 16550A by counting
+        * how many bytes are in the FIFO.
+        */
+       if (up->port.type == PORT_16550A && size_fifo(up) == 64) {
+               up->port.type = PORT_U6_16550A;
+               up->capabilities |= UART_CAP_AFE;
+       }
+}
+
+/*
+ * This routine is called by rs_init() to initialize a specific serial
+ * port.  It determines what type of UART chip this serial port is
+ * using: 8250, 16450, 16550, 16550A.  The important question is
+ * whether or not this UART is a 16550A or not, since this will
+ * determine whether or not we can use its FIFO features or not.
+ */
+static void autoconfig(struct uart_8250_port *up)
+{
+       unsigned char status1, scratch, scratch2, scratch3;
+       unsigned char save_lcr, save_mcr;
+       struct uart_port *port = &up->port;
+       unsigned long flags;
+       unsigned int old_capabilities;
+
+       if (!port->iobase && !port->mapbase && !port->membase)
+               return;
+
+       DEBUG_AUTOCONF("ttyS%d: autoconf (0x%04lx, 0x%p): ",
+                      serial_index(port), port->iobase, port->membase);
+
+       /*
+        * We really do need global IRQs disabled here - we're going to
+        * be frobbing the chips IRQ enable register to see if it exists.
+        */
+       spin_lock_irqsave(&port->lock, flags);
+
+       up->capabilities = 0;
+       up->bugs = 0;
+
+       if (!(port->flags & UPF_BUGGY_UART)) {
+               /*
+                * Do a simple existence test first; if we fail this,
+                * there's no point trying anything else.
+                *
+                * 0x80 is used as a nonsense port to prevent against
+                * false positives due to ISA bus float.  The
+                * assumption is that 0x80 is a non-existent port;
+                * which should be safe since include/asm/io.h also
+                * makes this assumption.
+                *
+                * Note: this is safe as long as MCR bit 4 is clear
+                * and the device is in "PC" mode.
+                */
+               scratch = serial_in(up, UART_IER);
+               serial_out(up, UART_IER, 0);
+#ifdef __i386__
+               outb(0xff, 0x080);
+#endif
+               /*
+                * Mask out IER[7:4] bits for test as some UARTs (e.g. TL
+                * 16C754B) allow only to modify them if an EFR bit is set.
+                */
+               scratch2 = serial_in(up, UART_IER) & 0x0f;
+               serial_out(up, UART_IER, 0x0F);
+#ifdef __i386__
+               outb(0, 0x080);
+#endif
+               scratch3 = serial_in(up, UART_IER) & 0x0f;
+               serial_out(up, UART_IER, scratch);
+               if (scratch2 != 0 || scratch3 != 0x0F) {
+                       /*
+                        * We failed; there's nothing here
+                        */
+                       spin_unlock_irqrestore(&port->lock, flags);
+                       DEBUG_AUTOCONF("IER test failed (%02x, %02x) ",
+                                      scratch2, scratch3);
+                       goto out;
+               }
+       }
+
+       save_mcr = serial_in(up, UART_MCR);
+       save_lcr = serial_in(up, UART_LCR);
+
+       /*
+        * Check to see if a UART is really there.  Certain broken
+        * internal modems based on the Rockwell chipset fail this
+        * test, because they apparently don't implement the loopback
+        * test mode.  So this test is skipped on the COM 1 through
+        * COM 4 ports.  This *should* be safe, since no board
+        * manufacturer would be stupid enough to design a board
+        * that conflicts with COM 1-4 --- we hope!
+        */
+       if (!(port->flags & UPF_SKIP_TEST)) {
+               serial_out(up, UART_MCR, UART_MCR_LOOP | 0x0A);
+               status1 = serial_in(up, UART_MSR) & 0xF0;
+               serial_out(up, UART_MCR, save_mcr);
+               if (status1 != 0x90) {
+                       spin_unlock_irqrestore(&port->lock, flags);
+                       DEBUG_AUTOCONF("LOOP test failed (%02x) ",
+                                      status1);
+                       goto out;
+               }
+       }
+
+       /*
+        * We're pretty sure there's a port here.  Lets find out what
+        * type of port it is.  The IIR top two bits allows us to find
+        * out if it's 8250 or 16450, 16550, 16550A or later.  This
+        * determines what we test for next.
+        *
+        * We also initialise the EFR (if any) to zero for later.  The
+        * EFR occupies the same register location as the FCR and IIR.
+        */
+       serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+       serial_out(up, UART_EFR, 0);
+       serial_out(up, UART_LCR, 0);
+
+       serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+       scratch = serial_in(up, UART_IIR) >> 6;
+
+       switch (scratch) {
+       case 0:
+               autoconfig_8250(up);
+               break;
+       case 1:
+               port->type = PORT_UNKNOWN;
+               break;
+       case 2:
+               port->type = PORT_16550;
+               break;
+       case 3:
+               autoconfig_16550a(up);
+               break;
+       }
+
+#ifdef CONFIG_SERIAL_8250_RSA
+       /*
+        * Only probe for RSA ports if we got the region.
+        */
+       if (port->type == PORT_16550A && up->probe & UART_PROBE_RSA &&
+           __enable_rsa(up))
+               port->type = PORT_RSA;
+#endif
+
+       serial_out(up, UART_LCR, save_lcr);
+
+       port->fifosize = uart_config[up->port.type].fifo_size;
+       old_capabilities = up->capabilities;
+       up->capabilities = uart_config[port->type].flags;
+       up->tx_loadsz = uart_config[port->type].tx_loadsz;
+
+       if (port->type == PORT_UNKNOWN)
+               goto out_lock;
+
+       /*
+        * Reset the UART.
+        */
+#ifdef CONFIG_SERIAL_8250_RSA
+       if (port->type == PORT_RSA)
+               serial_out(up, UART_RSA_FRR, 0);
+#endif
+       serial_out(up, UART_MCR, save_mcr);
+       serial8250_clear_fifos(up);
+       serial_in(up, UART_RX);
+       if (up->capabilities & UART_CAP_UUE)
+               serial_out(up, UART_IER, UART_IER_UUE);
+       else
+               serial_out(up, UART_IER, 0);
+
+out_lock:
+       spin_unlock_irqrestore(&port->lock, flags);
+       if (up->capabilities != old_capabilities) {
+               printk(KERN_WARNING
+                      "ttyS%d: detected caps %08x should be %08x\n",
+                      serial_index(port), old_capabilities,
+                      up->capabilities);
+       }
+out:
+       DEBUG_AUTOCONF("iir=%d ", scratch);
+       DEBUG_AUTOCONF("type=%s\n", uart_config[port->type].name);
+}
+
+static void autoconfig_irq(struct uart_8250_port *up)
+{
+       struct uart_port *port = &up->port;
+       unsigned char save_mcr, save_ier;
+       unsigned char save_ICP = 0;
+       unsigned int ICP = 0;
+       unsigned long irqs;
+       int irq;
+
+       if (port->flags & UPF_FOURPORT) {
+               ICP = (port->iobase & 0xfe0) | 0x1f;
+               save_ICP = inb_p(ICP);
+               outb_p(0x80, ICP);
+               inb_p(ICP);
+       }
+
+       /* forget possible initially masked and pending IRQ */
+       probe_irq_off(probe_irq_on());
+       save_mcr = serial_in(up, UART_MCR);
+       save_ier = serial_in(up, UART_IER);
+       serial_out(up, UART_MCR, UART_MCR_OUT1 | UART_MCR_OUT2);
+
+       irqs = probe_irq_on();
+       serial_out(up, UART_MCR, 0);
+       udelay(10);
+       if (port->flags & UPF_FOURPORT) {
+               serial_out(up, UART_MCR,
+                           UART_MCR_DTR | UART_MCR_RTS);
+       } else {
+               serial_out(up, UART_MCR,
+                           UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2);
+       }
+       serial_out(up, UART_IER, 0x0f); /* enable all intrs */
+       serial_in(up, UART_LSR);
+       serial_in(up, UART_RX);
+       serial_in(up, UART_IIR);
+       serial_in(up, UART_MSR);
+       serial_out(up, UART_TX, 0xFF);
+       udelay(20);
+       irq = probe_irq_off(irqs);
+
+       serial_out(up, UART_MCR, save_mcr);
+       serial_out(up, UART_IER, save_ier);
+
+       if (port->flags & UPF_FOURPORT)
+               outb_p(save_ICP, ICP);
+
+       port->irq = (irq > 0) ? irq : 0;
+}
+
+static inline void __stop_tx(struct uart_8250_port *p)
+{
+       if (p->ier & UART_IER_THRI) {
+               p->ier &= ~UART_IER_THRI;
+               serial_out(p, UART_IER, p->ier);
+               serial8250_rpm_put_tx(p);
+       }
+}
+
+static void serial8250_stop_tx(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+
+       serial8250_rpm_get(up);
+       __stop_tx(up);
+
+       /*
+        * We really want to stop the transmitter from sending.
+        */
+       if (port->type == PORT_16C950) {
+               up->acr |= UART_ACR_TXDIS;
+               serial_icr_write(up, UART_ACR, up->acr);
+       }
+       serial8250_rpm_put(up);
+}
+
+static void serial8250_start_tx(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+
+       serial8250_rpm_get_tx(up);
+
+       if (up->dma && !up->dma->tx_dma(up))
+               return;
+
+       if (!(up->ier & UART_IER_THRI)) {
+               up->ier |= UART_IER_THRI;
+               serial_port_out(port, UART_IER, up->ier);
+
+               if (up->bugs & UART_BUG_TXEN) {
+                       unsigned char lsr;
+                       lsr = serial_in(up, UART_LSR);
+                       up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+                       if (lsr & UART_LSR_THRE)
+                               serial8250_tx_chars(up);
+               }
+       }
+
+       /*
+        * Re-enable the transmitter if we disabled it.
+        */
+       if (port->type == PORT_16C950 && up->acr & UART_ACR_TXDIS) {
+               up->acr &= ~UART_ACR_TXDIS;
+               serial_icr_write(up, UART_ACR, up->acr);
+       }
+}
+
+static void serial8250_throttle(struct uart_port *port)
+{
+       port->throttle(port);
+}
+
+static void serial8250_unthrottle(struct uart_port *port)
+{
+       port->unthrottle(port);
+}
+
+static void serial8250_stop_rx(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+
+       serial8250_rpm_get(up);
+
+       up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
+       up->port.read_status_mask &= ~UART_LSR_DR;
+       serial_port_out(port, UART_IER, up->ier);
+
+       serial8250_rpm_put(up);
+}
+
+static void serial8250_disable_ms(struct uart_port *port)
+{
+       struct uart_8250_port *up =
+               container_of(port, struct uart_8250_port, port);
+
+       /* no MSR capabilities */
+       if (up->bugs & UART_BUG_NOMSR)
+               return;
+
+       up->ier &= ~UART_IER_MSI;
+       serial_port_out(port, UART_IER, up->ier);
+}
+
+static void serial8250_enable_ms(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+
+       /* no MSR capabilities */
+       if (up->bugs & UART_BUG_NOMSR)
+               return;
+
+       up->ier |= UART_IER_MSI;
+
+       serial8250_rpm_get(up);
+       serial_port_out(port, UART_IER, up->ier);
+       serial8250_rpm_put(up);
+}
+
+/*
+ * serial8250_rx_chars: processes according to the passed in LSR
+ * value, and returns the remaining LSR bits not handled
+ * by this Rx routine.
+ */
+unsigned char
+serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
+{
+       struct uart_port *port = &up->port;
+       unsigned char ch;
+       int max_count = 256;
+       char flag;
+
+       do {
+               if (likely(lsr & UART_LSR_DR))
+                       ch = serial_in(up, UART_RX);
+               else
+                       /*
+                        * Intel 82571 has a Serial Over Lan device that will
+                        * set UART_LSR_BI without setting UART_LSR_DR when
+                        * it receives a break. To avoid reading from the
+                        * receive buffer without UART_LSR_DR bit set, we
+                        * just force the read character to be 0
+                        */
+                       ch = 0;
+
+               flag = TTY_NORMAL;
+               port->icount.rx++;
+
+               lsr |= up->lsr_saved_flags;
+               up->lsr_saved_flags = 0;
+
+               if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
+                       if (lsr & UART_LSR_BI) {
+                               lsr &= ~(UART_LSR_FE | UART_LSR_PE);
+                               port->icount.brk++;
+                               /*
+                                * We do the SysRQ and SAK checking
+                                * here because otherwise the break
+                                * may get masked by ignore_status_mask
+                                * or read_status_mask.
+                                */
+                               if (uart_handle_break(port))
+                                       goto ignore_char;
+                       } else if (lsr & UART_LSR_PE)
+                               port->icount.parity++;
+                       else if (lsr & UART_LSR_FE)
+                               port->icount.frame++;
+                       if (lsr & UART_LSR_OE)
+                               port->icount.overrun++;
+
+                       /*
+                        * Mask off conditions which should be ignored.
+                        */
+                       lsr &= port->read_status_mask;
+
+                       if (lsr & UART_LSR_BI) {
+                               DEBUG_INTR("handling break....");
+                               flag = TTY_BREAK;
+                       } else if (lsr & UART_LSR_PE)
+                               flag = TTY_PARITY;
+                       else if (lsr & UART_LSR_FE)
+                               flag = TTY_FRAME;
+               }
+               if (uart_handle_sysrq_char(port, ch))
+                       goto ignore_char;
+
+               uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
+
+ignore_char:
+               lsr = serial_in(up, UART_LSR);
+       } while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (--max_count > 0));
+       spin_unlock(&port->lock);
+       tty_flip_buffer_push(&port->state->port);
+       spin_lock(&port->lock);
+       return lsr;
+}
+EXPORT_SYMBOL_GPL(serial8250_rx_chars);
+
+void serial8250_tx_chars(struct uart_8250_port *up)
+{
+       struct uart_port *port = &up->port;
+       struct circ_buf *xmit = &port->state->xmit;
+       int count;
+
+       if (port->x_char) {
+               serial_out(up, UART_TX, port->x_char);
+               port->icount.tx++;
+               port->x_char = 0;
+               return;
+       }
+       if (uart_tx_stopped(port)) {
+               serial8250_stop_tx(port);
+               return;
+       }
+       if (uart_circ_empty(xmit)) {
+               __stop_tx(up);
+               return;
+       }
+
+       count = up->tx_loadsz;
+       do {
+               serial_out(up, UART_TX, xmit->buf[xmit->tail]);
+               xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+               port->icount.tx++;
+               if (uart_circ_empty(xmit))
+                       break;
+               if (up->capabilities & UART_CAP_HFIFO) {
+                       if ((serial_port_in(port, UART_LSR) & BOTH_EMPTY) !=
+                           BOTH_EMPTY)
+                               break;
+               }
+       } while (--count > 0);
+
+       if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+               uart_write_wakeup(port);
+
+       DEBUG_INTR("THRE...");
+
+       /*
+        * With RPM enabled, we have to wait until the FIFO is empty before the
+        * HW can go idle. So we get here once again with empty FIFO and disable
+        * the interrupt and RPM in __stop_tx()
+        */
+       if (uart_circ_empty(xmit) && !(up->capabilities & UART_CAP_RPM))
+               __stop_tx(up);
+}
+EXPORT_SYMBOL_GPL(serial8250_tx_chars);
+
+/* Caller holds uart port lock */
+unsigned int serial8250_modem_status(struct uart_8250_port *up)
+{
+       struct uart_port *port = &up->port;
+       unsigned int status = serial_in(up, UART_MSR);
+
+       status |= up->msr_saved_flags;
+       up->msr_saved_flags = 0;
+       if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI &&
+           port->state != NULL) {
+               if (status & UART_MSR_TERI)
+                       port->icount.rng++;
+               if (status & UART_MSR_DDSR)
+                       port->icount.dsr++;
+               if (status & UART_MSR_DDCD)
+                       uart_handle_dcd_change(port, status & UART_MSR_DCD);
+               if (status & UART_MSR_DCTS)
+                       uart_handle_cts_change(port, status & UART_MSR_CTS);
+
+               wake_up_interruptible(&port->state->port.delta_msr_wait);
+       }
+
+       return status;
+}
+EXPORT_SYMBOL_GPL(serial8250_modem_status);
+
+/*
+ * This handles the interrupt from one port.
+ */
+int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
+{
+       unsigned char status;
+       unsigned long flags;
+       struct uart_8250_port *up = up_to_u8250p(port);
+       int dma_err = 0;
+
+       if (iir & UART_IIR_NO_INT)
+               return 0;
+
+       spin_lock_irqsave(&port->lock, flags);
+
+       status = serial_port_in(port, UART_LSR);
+
+       DEBUG_INTR("status = %x...", status);
+
+       if (status & (UART_LSR_DR | UART_LSR_BI)) {
+               if (up->dma)
+                       dma_err = up->dma->rx_dma(up, iir);
+
+               if (!up->dma || dma_err)
+                       status = serial8250_rx_chars(up, status);
+       }
+       serial8250_modem_status(up);
+       if ((!up->dma || (up->dma && up->dma->tx_err)) &&
+           (status & UART_LSR_THRE))
+               serial8250_tx_chars(up);
+
+       spin_unlock_irqrestore(&port->lock, flags);
+       return 1;
+}
+EXPORT_SYMBOL_GPL(serial8250_handle_irq);
+
+static int serial8250_default_handle_irq(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned int iir;
+       int ret;
+
+       serial8250_rpm_get(up);
+
+       iir = serial_port_in(port, UART_IIR);
+       ret = serial8250_handle_irq(port, iir);
+
+       serial8250_rpm_put(up);
+       return ret;
+}
+
+/*
+ * These Exar UARTs have an extra interrupt indicator that could
+ * fire for a few unimplemented interrupts.  One of which is a
+ * wakeup event when coming out of sleep.  Put this here just
+ * to be on the safe side that these interrupts don't go unhandled.
+ */
+static int exar_handle_irq(struct uart_port *port)
+{
+       unsigned char int0, int1, int2, int3;
+       unsigned int iir = serial_port_in(port, UART_IIR);
+       int ret;
+
+       ret = serial8250_handle_irq(port, iir);
+
+       if ((port->type == PORT_XR17V35X) ||
+          (port->type == PORT_XR17D15X)) {
+               int0 = serial_port_in(port, 0x80);
+               int1 = serial_port_in(port, 0x81);
+               int2 = serial_port_in(port, 0x82);
+               int3 = serial_port_in(port, 0x83);
+       }
+
+       return ret;
+}
+
+static unsigned int serial8250_tx_empty(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned long flags;
+       unsigned int lsr;
+
+       serial8250_rpm_get(up);
+
+       spin_lock_irqsave(&port->lock, flags);
+       lsr = serial_port_in(port, UART_LSR);
+       up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       serial8250_rpm_put(up);
+
+       return (lsr & BOTH_EMPTY) == BOTH_EMPTY ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int serial8250_get_mctrl(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned int status;
+       unsigned int ret;
+
+       serial8250_rpm_get(up);
+       status = serial8250_modem_status(up);
+       serial8250_rpm_put(up);
+
+       ret = 0;
+       if (status & UART_MSR_DCD)
+               ret |= TIOCM_CAR;
+       if (status & UART_MSR_RI)
+               ret |= TIOCM_RNG;
+       if (status & UART_MSR_DSR)
+               ret |= TIOCM_DSR;
+       if (status & UART_MSR_CTS)
+               ret |= TIOCM_CTS;
+       return ret;
+}
+
+void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned char mcr = 0;
+
+       if (mctrl & TIOCM_RTS)
+               mcr |= UART_MCR_RTS;
+       if (mctrl & TIOCM_DTR)
+               mcr |= UART_MCR_DTR;
+       if (mctrl & TIOCM_OUT1)
+               mcr |= UART_MCR_OUT1;
+       if (mctrl & TIOCM_OUT2)
+               mcr |= UART_MCR_OUT2;
+       if (mctrl & TIOCM_LOOP)
+               mcr |= UART_MCR_LOOP;
+
+       mcr = (mcr & up->mcr_mask) | up->mcr_force | up->mcr;
+
+       serial_port_out(port, UART_MCR, mcr);
+}
+EXPORT_SYMBOL_GPL(serial8250_do_set_mctrl);
+
+static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+       if (port->set_mctrl)
+               port->set_mctrl(port, mctrl);
+       else
+               serial8250_do_set_mctrl(port, mctrl);
+}
+
+static void serial8250_break_ctl(struct uart_port *port, int break_state)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned long flags;
+
+       serial8250_rpm_get(up);
+       spin_lock_irqsave(&port->lock, flags);
+       if (break_state == -1)
+               up->lcr |= UART_LCR_SBC;
+       else
+               up->lcr &= ~UART_LCR_SBC;
+       serial_port_out(port, UART_LCR, up->lcr);
+       spin_unlock_irqrestore(&port->lock, flags);
+       serial8250_rpm_put(up);
+}
+
+/*
+ *     Wait for transmitter & holding register to empty
+ */
+static void wait_for_xmitr(struct uart_8250_port *up, int bits)
+{
+       unsigned int status, tmout = 10000;
+
+       /* Wait up to 10ms for the character(s) to be sent. */
+       for (;;) {
+               status = serial_in(up, UART_LSR);
+
+               up->lsr_saved_flags |= status & LSR_SAVE_FLAGS;
+
+               if ((status & bits) == bits)
+                       break;
+               if (--tmout == 0)
+                       break;
+               udelay(1);
+       }
+
+       /* Wait up to 1s for flow control if necessary */
+       if (up->port.flags & UPF_CONS_FLOW) {
+               unsigned int tmout;
+               for (tmout = 1000000; tmout; tmout--) {
+                       unsigned int msr = serial_in(up, UART_MSR);
+                       up->msr_saved_flags |= msr & MSR_SAVE_FLAGS;
+                       if (msr & UART_MSR_CTS)
+                               break;
+                       udelay(1);
+                       touch_nmi_watchdog();
+               }
+       }
+}
+
+#ifdef CONFIG_CONSOLE_POLL
+/*
+ * Console polling routines for writing and reading from the uart while
+ * in an interrupt or debug context.
+ */
+
+static int serial8250_get_poll_char(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned char lsr;
+       int status;
+
+       serial8250_rpm_get(up);
+
+       lsr = serial_port_in(port, UART_LSR);
+
+       if (!(lsr & UART_LSR_DR)) {
+               status = NO_POLL_CHAR;
+               goto out;
+       }
+
+       status = serial_port_in(port, UART_RX);
+out:
+       serial8250_rpm_put(up);
+       return status;
+}
+
+
+static void serial8250_put_poll_char(struct uart_port *port,
+                        unsigned char c)
+{
+       unsigned int ier;
+       struct uart_8250_port *up = up_to_u8250p(port);
+
+       serial8250_rpm_get(up);
+       /*
+        *      First save the IER then disable the interrupts
+        */
+       ier = serial_port_in(port, UART_IER);
+       if (up->capabilities & UART_CAP_UUE)
+               serial_port_out(port, UART_IER, UART_IER_UUE);
+       else
+               serial_port_out(port, UART_IER, 0);
+
+       wait_for_xmitr(up, BOTH_EMPTY);
+       /*
+        *      Send the character out.
+        */
+       serial_port_out(port, UART_TX, c);
+
+       /*
+        *      Finally, wait for transmitter to become empty
+        *      and restore the IER
+        */
+       wait_for_xmitr(up, BOTH_EMPTY);
+       serial_port_out(port, UART_IER, ier);
+       serial8250_rpm_put(up);
+}
+
+#endif /* CONFIG_CONSOLE_POLL */
+
+int serial8250_do_startup(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned long flags;
+       unsigned char lsr, iir;
+       int retval;
+
+       if (port->type == PORT_8250_CIR)
+               return -ENODEV;
+
+       if (!port->fifosize)
+               port->fifosize = uart_config[port->type].fifo_size;
+       if (!up->tx_loadsz)
+               up->tx_loadsz = uart_config[port->type].tx_loadsz;
+       if (!up->capabilities)
+               up->capabilities = uart_config[port->type].flags;
+       up->mcr = 0;
+
+       if (port->iotype != up->cur_iotype)
+               set_io_from_upio(port);
+
+       serial8250_rpm_get(up);
+       if (port->type == PORT_16C950) {
+               /* Wake up and initialize UART */
+               up->acr = 0;
+               serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
+               serial_port_out(port, UART_EFR, UART_EFR_ECB);
+               serial_port_out(port, UART_IER, 0);
+               serial_port_out(port, UART_LCR, 0);
+               serial_icr_write(up, UART_CSR, 0); /* Reset the UART */
+               serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
+               serial_port_out(port, UART_EFR, UART_EFR_ECB);
+               serial_port_out(port, UART_LCR, 0);
+       }
+
+#ifdef CONFIG_SERIAL_8250_RSA
+       /*
+        * If this is an RSA port, see if we can kick it up to the
+        * higher speed clock.
+        */
+       enable_rsa(up);
+#endif
+       /*
+        * Clear the FIFO buffers and disable them.
+        * (they will be reenabled in set_termios())
+        */
+       serial8250_clear_fifos(up);
+
+       /*
+        * Clear the interrupt registers.
+        */
+       serial_port_in(port, UART_LSR);
+       serial_port_in(port, UART_RX);
+       serial_port_in(port, UART_IIR);
+       serial_port_in(port, UART_MSR);
+
+       /*
+        * At this point, there's no way the LSR could still be 0xff;
+        * if it is, then bail out, because there's likely no UART
+        * here.
+        */
+       if (!(port->flags & UPF_BUGGY_UART) &&
+           (serial_port_in(port, UART_LSR) == 0xff)) {
+               printk_ratelimited(KERN_INFO "ttyS%d: LSR safety check engaged!\n",
+                                  serial_index(port));
+               retval = -ENODEV;
+               goto out;
+       }
+
+       /*
+        * For a XR16C850, we need to set the trigger levels
+        */
+       if (port->type == PORT_16850) {
+               unsigned char fctr;
+
+               serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
+
+               fctr = serial_in(up, UART_FCTR) & ~(UART_FCTR_RX|UART_FCTR_TX);
+               serial_port_out(port, UART_FCTR,
+                               fctr | UART_FCTR_TRGD | UART_FCTR_RX);
+               serial_port_out(port, UART_TRG, UART_TRG_96);
+               serial_port_out(port, UART_FCTR,
+                               fctr | UART_FCTR_TRGD | UART_FCTR_TX);
+               serial_port_out(port, UART_TRG, UART_TRG_96);
+
+               serial_port_out(port, UART_LCR, 0);
+       }
+
+       if (port->irq) {
+               unsigned char iir1;
+               /*
+                * Test for UARTs that do not reassert THRE when the
+                * transmitter is idle and the interrupt has already
+                * been cleared.  Real 16550s should always reassert
+                * this interrupt whenever the transmitter is idle and
+                * the interrupt is enabled.  Delays are necessary to
+                * allow register changes to become visible.
+                */
+               spin_lock_irqsave(&port->lock, flags);
+               if (up->port.irqflags & IRQF_SHARED)
+                       disable_irq_nosync(port->irq);
+
+               wait_for_xmitr(up, UART_LSR_THRE);
+               serial_port_out_sync(port, UART_IER, UART_IER_THRI);
+               udelay(1); /* allow THRE to set */
+               iir1 = serial_port_in(port, UART_IIR);
+               serial_port_out(port, UART_IER, 0);
+               serial_port_out_sync(port, UART_IER, UART_IER_THRI);
+               udelay(1); /* allow a working UART time to re-assert THRE */
+               iir = serial_port_in(port, UART_IIR);
+               serial_port_out(port, UART_IER, 0);
+
+               if (port->irqflags & IRQF_SHARED)
+                       enable_irq(port->irq);
+               spin_unlock_irqrestore(&port->lock, flags);
+
+               /*
+                * If the interrupt is not reasserted, or we otherwise
+                * don't trust the iir, setup a timer to kick the UART
+                * on a regular basis.
+                */
+               if ((!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) ||
+                   up->port.flags & UPF_BUG_THRE) {
+                       up->bugs |= UART_BUG_THRE;
+               }
+       }
+
+       retval = up->ops->setup_irq(up);
+       if (retval)
+               goto out;
+
+       /*
+        * Now, initialize the UART
+        */
+       serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
+
+       spin_lock_irqsave(&port->lock, flags);
+       if (up->port.flags & UPF_FOURPORT) {
+               if (!up->port.irq)
+                       up->port.mctrl |= TIOCM_OUT1;
+       } else
+               /*
+                * Most PC uarts need OUT2 raised to enable interrupts.
+                */
+               if (port->irq)
+                       up->port.mctrl |= TIOCM_OUT2;
+
+       serial8250_set_mctrl(port, port->mctrl);
+
+       /* Serial over Lan (SoL) hack:
+          Intel 8257x Gigabit ethernet chips have a
+          16550 emulation, to be used for Serial Over Lan.
+          Those chips take a longer time than a normal
+          serial device to signalize that a transmission
+          data was queued. Due to that, the above test generally
+          fails. One solution would be to delay the reading of
+          iir. However, this is not reliable, since the timeout
+          is variable. So, let's just don't test if we receive
+          TX irq. This way, we'll never enable UART_BUG_TXEN.
+        */
+       if (up->port.flags & UPF_NO_TXEN_TEST)
+               goto dont_test_tx_en;
+
+       /*
+        * Do a quick test to see if we receive an
+        * interrupt when we enable the TX irq.
+        */
+       serial_port_out(port, UART_IER, UART_IER_THRI);
+       lsr = serial_port_in(port, UART_LSR);
+       iir = serial_port_in(port, UART_IIR);
+       serial_port_out(port, UART_IER, 0);
+
+       if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT) {
+               if (!(up->bugs & UART_BUG_TXEN)) {
+                       up->bugs |= UART_BUG_TXEN;
+                       pr_debug("ttyS%d - enabling bad tx status workarounds\n",
+                                serial_index(port));
+               }
+       } else {
+               up->bugs &= ~UART_BUG_TXEN;
+       }
+
+dont_test_tx_en:
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       /*
+        * Clear the interrupt registers again for luck, and clear the
+        * saved flags to avoid getting false values from polling
+        * routines or the previous session.
+        */
+       serial_port_in(port, UART_LSR);
+       serial_port_in(port, UART_RX);
+       serial_port_in(port, UART_IIR);
+       serial_port_in(port, UART_MSR);
+       up->lsr_saved_flags = 0;
+       up->msr_saved_flags = 0;
+
+       /*
+        * Request DMA channels for both RX and TX.
+        */
+       if (up->dma) {
+               retval = serial8250_request_dma(up);
+               if (retval) {
+                       pr_warn_ratelimited("ttyS%d - failed to request DMA\n",
+                                           serial_index(port));
+                       up->dma = NULL;
+               }
+       }
+
+       /*
+        * Finally, enable interrupts.  Note: Modem status interrupts
+        * are set via set_termios(), which will be occurring imminently
+        * anyway, so we don't enable them here.
+        */
+       up->ier = UART_IER_RLSI | UART_IER_RDI;
+       serial_port_out(port, UART_IER, up->ier);
+
+       if (port->flags & UPF_FOURPORT) {
+               unsigned int icp;
+               /*
+                * Enable interrupts on the AST Fourport board
+                */
+               icp = (port->iobase & 0xfe0) | 0x01f;
+               outb_p(0x80, icp);
+               inb_p(icp);
+       }
+       retval = 0;
+out:
+       serial8250_rpm_put(up);
+       return retval;
+}
+EXPORT_SYMBOL_GPL(serial8250_do_startup);
+
+static int serial8250_startup(struct uart_port *port)
+{
+       if (port->startup)
+               return port->startup(port);
+       return serial8250_do_startup(port);
+}
+
+void serial8250_do_shutdown(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned long flags;
+
+       serial8250_rpm_get(up);
+       /*
+        * Disable interrupts from this port
+        */
+       up->ier = 0;
+       serial_port_out(port, UART_IER, 0);
+
+       if (up->dma)
+               serial8250_release_dma(up);
+
+       spin_lock_irqsave(&port->lock, flags);
+       if (port->flags & UPF_FOURPORT) {
+               /* reset interrupts on the AST Fourport board */
+               inb((port->iobase & 0xfe0) | 0x1f);
+               port->mctrl |= TIOCM_OUT1;
+       } else
+               port->mctrl &= ~TIOCM_OUT2;
+
+       serial8250_set_mctrl(port, port->mctrl);
+       spin_unlock_irqrestore(&port->lock, flags);
+
+       /*
+        * Disable break condition and FIFOs
+        */
+       serial_port_out(port, UART_LCR,
+                       serial_port_in(port, UART_LCR) & ~UART_LCR_SBC);
+       serial8250_clear_fifos(up);
+
+#ifdef CONFIG_SERIAL_8250_RSA
+       /*
+        * Reset the RSA board back to 115kbps compat mode.
+        */
+       disable_rsa(up);
+#endif
+
+       /*
+        * Read data port to reset things, and then unlink from
+        * the IRQ chain.
+        */
+       serial_port_in(port, UART_RX);
+       serial8250_rpm_put(up);
+
+       up->ops->release_irq(up);
+}
+EXPORT_SYMBOL_GPL(serial8250_do_shutdown);
+
+static void serial8250_shutdown(struct uart_port *port)
+{
+       if (port->shutdown)
+               port->shutdown(port);
+       else
+               serial8250_do_shutdown(port);
+}
+
+/*
+ * XR17V35x UARTs have an extra fractional divisor register (DLD)
+ * Calculate divisor with extra 4-bit fractional portion
+ */
+static unsigned int xr17v35x_get_divisor(struct uart_8250_port *up,
+                                        unsigned int baud,
+                                        unsigned int *frac)
+{
+       struct uart_port *port = &up->port;
+       unsigned int quot_16;
+
+       quot_16 = DIV_ROUND_CLOSEST(port->uartclk, baud);
+       *frac = quot_16 & 0x0f;
+
+       return quot_16 >> 4;
+}
+
+static unsigned int serial8250_get_divisor(struct uart_8250_port *up,
+                                          unsigned int baud,
+                                          unsigned int *frac)
+{
+       struct uart_port *port = &up->port;
+       unsigned int quot;
+
+       /*
+        * Handle magic divisors for baud rates above baud_base on
+        * SMSC SuperIO chips.
+        *
+        */
+       if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
+           baud == (port->uartclk/4))
+               quot = 0x8001;
+       else if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
+                baud == (port->uartclk/8))
+               quot = 0x8002;
+       else if (up->port.type == PORT_XR17V35X)
+               quot = xr17v35x_get_divisor(up, baud, frac);
+       else
+               quot = uart_get_divisor(port, baud);
+
+       /*
+        * Oxford Semi 952 rev B workaround
+        */
+       if (up->bugs & UART_BUG_QUOT && (quot & 0xff) == 0)
+               quot++;
+
+       return quot;
+}
+
+static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
+                                           tcflag_t c_cflag)
+{
+       unsigned char cval;
+
+       switch (c_cflag & CSIZE) {
+       case CS5:
+               cval = UART_LCR_WLEN5;
+               break;
+       case CS6:
+               cval = UART_LCR_WLEN6;
+               break;
+       case CS7:
+               cval = UART_LCR_WLEN7;
+               break;
+       default:
+       case CS8:
+               cval = UART_LCR_WLEN8;
+               break;
+       }
+
+       if (c_cflag & CSTOPB)
+               cval |= UART_LCR_STOP;
+       if (c_cflag & PARENB) {
+               cval |= UART_LCR_PARITY;
+               if (up->bugs & UART_BUG_PARITY)
+                       up->fifo_bug = true;
+       }
+       if (!(c_cflag & PARODD))
+               cval |= UART_LCR_EPAR;
+#ifdef CMSPAR
+       if (c_cflag & CMSPAR)
+               cval |= UART_LCR_SPAR;
+#endif
+
+       return cval;
+}
+
+static void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
+                           unsigned int quot, unsigned int quot_frac)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+
+       /* Workaround to enable 115200 baud on OMAP1510 internal ports */
+       if (is_omap1510_8250(up)) {
+               if (baud == 115200) {
+                       quot = 1;
+                       serial_port_out(port, UART_OMAP_OSC_12M_SEL, 1);
+               } else
+                       serial_port_out(port, UART_OMAP_OSC_12M_SEL, 0);
+       }
+
+       /*
+        * For NatSemi, switch to bank 2 not bank 1, to avoid resetting EXCR2,
+        * otherwise just set DLAB
+        */
+       if (up->capabilities & UART_NATSEMI)
+               serial_port_out(port, UART_LCR, 0xe0);
+       else
+               serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
+
+       serial_dl_write(up, quot);
+
+       /* XR17V35x UARTs have an extra fractional divisor register (DLD) */
+       if (up->port.type == PORT_XR17V35X)
+               serial_port_out(port, 0x2, quot_frac);
+}
+
+void
+serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
+                         struct ktermios *old)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       unsigned char cval;
+       unsigned long flags;
+       unsigned int baud, quot, frac = 0;
+
+       cval = serial8250_compute_lcr(up, termios->c_cflag);
+
+       /*
+        * Ask the core to calculate the divisor for us.
+        */
+       baud = uart_get_baud_rate(port, termios, old,
+                                 port->uartclk / 16 / 0xffff,
+                                 port->uartclk / 16);
+       quot = serial8250_get_divisor(up, baud, &frac);
+
+       /*
+        * Ok, we're now changing the port state.  Do it with
+        * interrupts disabled.
+        */
+       serial8250_rpm_get(up);
+       spin_lock_irqsave(&port->lock, flags);
+
+       up->lcr = cval;                                 /* Save computed LCR */
+
+       if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
+               /* NOTE: If fifo_bug is not set, a user can set RX_trigger. */
+               if ((baud < 2400 && !up->dma) || up->fifo_bug) {
+                       up->fcr &= ~UART_FCR_TRIGGER_MASK;
+                       up->fcr |= UART_FCR_TRIGGER_1;
+               }
+       }
+
+       /*
+        * MCR-based auto flow control.  When AFE is enabled, RTS will be
+        * deasserted when the receive FIFO contains more characters than
+        * the trigger, or the MCR RTS bit is cleared.  In the case where
+        * the remote UART is not using CTS auto flow control, we must
+        * have sufficient FIFO entries for the latency of the remote
+        * UART to respond.  IOW, at least 32 bytes of FIFO.
+        */
+       if (up->capabilities & UART_CAP_AFE && port->fifosize >= 32) {
+               up->mcr &= ~UART_MCR_AFE;
+               if (termios->c_cflag & CRTSCTS)
+                       up->mcr |= UART_MCR_AFE;
+       }
+
+       /*
+        * Update the per-port timeout.
+        */
+       uart_update_timeout(port, termios->c_cflag, baud);
+
+       port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
+       if (termios->c_iflag & INPCK)
+               port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
+       if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
+               port->read_status_mask |= UART_LSR_BI;
+
+       /*
+        * Characteres to ignore
+        */
+       port->ignore_status_mask = 0;
+       if (termios->c_iflag & IGNPAR)
+               port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
+       if (termios->c_iflag & IGNBRK) {
+               port->ignore_status_mask |= UART_LSR_BI;
+               /*
+                * If we're ignoring parity and break indicators,
+                * ignore overruns too (for real raw support).
+                */
+               if (termios->c_iflag & IGNPAR)
+                       port->ignore_status_mask |= UART_LSR_OE;
+       }
+
+       /*
+        * ignore all characters if CREAD is not set
+        */
+       if ((termios->c_cflag & CREAD) == 0)
+               port->ignore_status_mask |= UART_LSR_DR;
+
+       /*
+        * CTS flow control flag and modem status interrupts
+        */
+       up->ier &= ~UART_IER_MSI;
+       if (!(up->bugs & UART_BUG_NOMSR) &&
+                       UART_ENABLE_MS(&up->port, termios->c_cflag))
+               up->ier |= UART_IER_MSI;
+       if (up->capabilities & UART_CAP_UUE)
+               up->ier |= UART_IER_UUE;
+       if (up->capabilities & UART_CAP_RTOIE)
+               up->ier |= UART_IER_RTOIE;
+
+       serial_port_out(port, UART_IER, up->ier);
+
+       if (up->capabilities & UART_CAP_EFR) {
+               unsigned char efr = 0;
+               /*
+                * TI16C752/Startech hardware flow control.  FIXME:
+                * - TI16C752 requires control thresholds to be set.
+                * - UART_MCR_RTS is ineffective if auto-RTS mode is enabled.
+                */
+               if (termios->c_cflag & CRTSCTS)
+                       efr |= UART_EFR_CTS;
+
+               serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
+               if (port->flags & UPF_EXAR_EFR)
+                       serial_port_out(port, UART_XR_EFR, efr);
+               else
+                       serial_port_out(port, UART_EFR, efr);
+       }
+
+       serial8250_set_divisor(port, baud, quot, frac);
+
+       /*
+        * LCR DLAB must be set to enable 64-byte FIFO mode. If the FCR
+        * is written without DLAB set, this mode will be disabled.
+        */
+       if (port->type == PORT_16750)
+               serial_port_out(port, UART_FCR, up->fcr);
+
+       serial_port_out(port, UART_LCR, up->lcr);       /* reset DLAB */
+       if (port->type != PORT_16750) {
+               /* emulated UARTs (Lucent Venus 167x) need two steps */
+               if (up->fcr & UART_FCR_ENABLE_FIFO)
+                       serial_port_out(port, UART_FCR, UART_FCR_ENABLE_FIFO);
+               serial_port_out(port, UART_FCR, up->fcr);       /* set fcr */
+       }
+       serial8250_set_mctrl(port, port->mctrl);
+       spin_unlock_irqrestore(&port->lock, flags);
+       serial8250_rpm_put(up);
+
+       /* Don't rewrite B0 */
+       if (tty_termios_baud_rate(termios))
+               tty_termios_encode_baud_rate(termios, baud, baud);
+}
+EXPORT_SYMBOL(serial8250_do_set_termios);
+
+static void
+serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
+                      struct ktermios *old)
+{
+       if (port->set_termios)
+               port->set_termios(port, termios, old);
+       else
+               serial8250_do_set_termios(port, termios, old);
+}
+
+static void
+serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios)
+{
+       if (termios->c_line == N_PPS) {
+               port->flags |= UPF_HARDPPS_CD;
+               spin_lock_irq(&port->lock);
+               serial8250_enable_ms(port);
+               spin_unlock_irq(&port->lock);
+       } else {
+               port->flags &= ~UPF_HARDPPS_CD;
+               if (!UART_ENABLE_MS(port, termios->c_cflag)) {
+                       spin_lock_irq(&port->lock);
+                       serial8250_disable_ms(port);
+                       spin_unlock_irq(&port->lock);
+               }
+       }
+}
+
+
+void serial8250_do_pm(struct uart_port *port, unsigned int state,
+                     unsigned int oldstate)
+{
+       struct uart_8250_port *p = up_to_u8250p(port);
+
+       serial8250_set_sleep(p, state != 0);
+}
+EXPORT_SYMBOL(serial8250_do_pm);
+
+static void
+serial8250_pm(struct uart_port *port, unsigned int state,
+             unsigned int oldstate)
+{
+       if (port->pm)
+               port->pm(port, state, oldstate);
+       else
+               serial8250_do_pm(port, state, oldstate);
+}
+
+static unsigned int serial8250_port_size(struct uart_8250_port *pt)
+{
+       if (pt->port.mapsize)
+               return pt->port.mapsize;
+       if (pt->port.iotype == UPIO_AU) {
+               if (pt->port.type == PORT_RT2880)
+                       return 0x100;
+               return 0x1000;
+       }
+       if (is_omap1_8250(pt))
+               return 0x16 << pt->port.regshift;
+
+       return 8 << pt->port.regshift;
+}
+
+/*
+ * Resource handling.
+ */
+static int serial8250_request_std_resource(struct uart_8250_port *up)
+{
+       unsigned int size = serial8250_port_size(up);
+       struct uart_port *port = &up->port;
+       int ret = 0;
+
+       switch (port->iotype) {
+       case UPIO_AU:
+       case UPIO_TSI:
+       case UPIO_MEM32:
+       case UPIO_MEM32BE:
+       case UPIO_MEM:
+               if (!port->mapbase)
+                       break;
+
+               if (!request_mem_region(port->mapbase, size, "serial")) {
+                       ret = -EBUSY;
+                       break;
+               }
+
+               if (port->flags & UPF_IOREMAP) {
+                       port->membase = ioremap_nocache(port->mapbase, size);
+                       if (!port->membase) {
+                               release_mem_region(port->mapbase, size);
+                               ret = -ENOMEM;
+                       }
+               }
+               break;
+
+       case UPIO_HUB6:
+       case UPIO_PORT:
+               if (!request_region(port->iobase, size, "serial"))
+                       ret = -EBUSY;
+               break;
+       }
+       return ret;
+}
+
+static void serial8250_release_std_resource(struct uart_8250_port *up)
+{
+       unsigned int size = serial8250_port_size(up);
+       struct uart_port *port = &up->port;
+
+       switch (port->iotype) {
+       case UPIO_AU:
+       case UPIO_TSI:
+       case UPIO_MEM32:
+       case UPIO_MEM32BE:
+       case UPIO_MEM:
+               if (!port->mapbase)
+                       break;
+
+               if (port->flags & UPF_IOREMAP) {
+                       iounmap(port->membase);
+                       port->membase = NULL;
+               }
+
+               release_mem_region(port->mapbase, size);
+               break;
+
+       case UPIO_HUB6:
+       case UPIO_PORT:
+               release_region(port->iobase, size);
+               break;
+       }
+}
+
+static void serial8250_release_port(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+
+       serial8250_release_std_resource(up);
+}
+
+static int serial8250_request_port(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       int ret;
+
+       if (port->type == PORT_8250_CIR)
+               return -ENODEV;
+
+       ret = serial8250_request_std_resource(up);
+
+       return ret;
+}
+
+static int fcr_get_rxtrig_bytes(struct uart_8250_port *up)
+{
+       const struct serial8250_config *conf_type = &uart_config[up->port.type];
+       unsigned char bytes;
+
+       bytes = conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(up->fcr)];
+
+       return bytes ? bytes : -EOPNOTSUPP;
+}
+
+static int bytes_to_fcr_rxtrig(struct uart_8250_port *up, unsigned char bytes)
+{
+       const struct serial8250_config *conf_type = &uart_config[up->port.type];
+       int i;
+
+       if (!conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(UART_FCR_R_TRIG_00)])
+               return -EOPNOTSUPP;
+
+       for (i = 1; i < UART_FCR_R_TRIG_MAX_STATE; i++) {
+               if (bytes < conf_type->rxtrig_bytes[i])
+                       /* Use the nearest lower value */
+                       return (--i) << UART_FCR_R_TRIG_SHIFT;
+       }
+
+       return UART_FCR_R_TRIG_11;
+}
+
+static int do_get_rxtrig(struct tty_port *port)
+{
+       struct uart_state *state = container_of(port, struct uart_state, port);
+       struct uart_port *uport = state->uart_port;
+       struct uart_8250_port *up =
+               container_of(uport, struct uart_8250_port, port);
+
+       if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1)
+               return -EINVAL;
+
+       return fcr_get_rxtrig_bytes(up);
+}
+
+static int do_serial8250_get_rxtrig(struct tty_port *port)
+{
+       int rxtrig_bytes;
+
+       mutex_lock(&port->mutex);
+       rxtrig_bytes = do_get_rxtrig(port);
+       mutex_unlock(&port->mutex);
+
+       return rxtrig_bytes;
+}
+
+static ssize_t serial8250_get_attr_rx_trig_bytes(struct device *dev,
+       struct device_attribute *attr, char *buf)
+{
+       struct tty_port *port = dev_get_drvdata(dev);
+       int rxtrig_bytes;
+
+       rxtrig_bytes = do_serial8250_get_rxtrig(port);
+       if (rxtrig_bytes < 0)
+               return rxtrig_bytes;
+
+       return snprintf(buf, PAGE_SIZE, "%d\n", rxtrig_bytes);
+}
+
+static int do_set_rxtrig(struct tty_port *port, unsigned char bytes)
+{
+       struct uart_state *state = container_of(port, struct uart_state, port);
+       struct uart_port *uport = state->uart_port;
+       struct uart_8250_port *up =
+               container_of(uport, struct uart_8250_port, port);
+       int rxtrig;
+
+       if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1 ||
+           up->fifo_bug)
+               return -EINVAL;
+
+       rxtrig = bytes_to_fcr_rxtrig(up, bytes);
+       if (rxtrig < 0)
+               return rxtrig;
+
+       serial8250_clear_fifos(up);
+       up->fcr &= ~UART_FCR_TRIGGER_MASK;
+       up->fcr |= (unsigned char)rxtrig;
+       serial_out(up, UART_FCR, up->fcr);
+       return 0;
+}
+
+static int do_serial8250_set_rxtrig(struct tty_port *port, unsigned char bytes)
+{
+       int ret;
+
+       mutex_lock(&port->mutex);
+       ret = do_set_rxtrig(port, bytes);
+       mutex_unlock(&port->mutex);
+
+       return ret;
+}
+
+static ssize_t serial8250_set_attr_rx_trig_bytes(struct device *dev,
+       struct device_attribute *attr, const char *buf, size_t count)
+{
+       struct tty_port *port = dev_get_drvdata(dev);
+       unsigned char bytes;
+       int ret;
+
+       if (!count)
+               return -EINVAL;
+
+       ret = kstrtou8(buf, 10, &bytes);
+       if (ret < 0)
+               return ret;
+
+       ret = do_serial8250_set_rxtrig(port, bytes);
+       if (ret < 0)
+               return ret;
+
+       return count;
+}
+
+static DEVICE_ATTR(rx_trig_bytes, S_IRUSR | S_IWUSR | S_IRGRP,
+                  serial8250_get_attr_rx_trig_bytes,
+                  serial8250_set_attr_rx_trig_bytes);
+
+static struct attribute *serial8250_dev_attrs[] = {
+       &dev_attr_rx_trig_bytes.attr,
+       NULL,
+       };
+
+static struct attribute_group serial8250_dev_attr_group = {
+       .attrs = serial8250_dev_attrs,
+       };
+
+static void register_dev_spec_attr_grp(struct uart_8250_port *up)
+{
+       const struct serial8250_config *conf_type = &uart_config[up->port.type];
+
+       if (conf_type->rxtrig_bytes[0])
+               up->port.attr_group = &serial8250_dev_attr_group;
+}
+
+static void serial8250_config_port(struct uart_port *port, int flags)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+       int ret;
+
+       if (port->type == PORT_8250_CIR)
+               return;
+
+       /*
+        * Find the region that we can probe for.  This in turn
+        * tells us whether we can probe for the type of port.
+        */
+       ret = serial8250_request_std_resource(up);
+       if (ret < 0)
+               return;
+
+       if (port->iotype != up->cur_iotype)
+               set_io_from_upio(port);
+
+       if (flags & UART_CONFIG_TYPE)
+               autoconfig(up);
+
+       /* if access method is AU, it is a 16550 with a quirk */
+       if (port->type == PORT_16550A && port->iotype == UPIO_AU)
+               up->bugs |= UART_BUG_NOMSR;
+
+       /* HW bugs may trigger IRQ while IIR == NO_INT */
+       if (port->type == PORT_TEGRA)
+               up->bugs |= UART_BUG_NOMSR;
+
+       if (port->type != PORT_UNKNOWN && flags & UART_CONFIG_IRQ)
+               autoconfig_irq(up);
+
+       if (port->type == PORT_UNKNOWN)
+               serial8250_release_std_resource(up);
+
+       /* Fixme: probably not the best place for this */
+       if ((port->type == PORT_XR17V35X) ||
+          (port->type == PORT_XR17D15X))
+               port->handle_irq = exar_handle_irq;
+
+       register_dev_spec_attr_grp(up);
+       up->fcr = uart_config[up->port.type].fcr;
+}
+
+static int
+serial8250_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+       if (ser->irq >= nr_irqs || ser->irq < 0 ||
+           ser->baud_base < 9600 || ser->type < PORT_UNKNOWN ||
+           ser->type >= ARRAY_SIZE(uart_config) || ser->type == PORT_CIRRUS ||
+           ser->type == PORT_STARTECH)
+               return -EINVAL;
+       return 0;
+}
+
+static const char *
+serial8250_type(struct uart_port *port)
+{
+       int type = port->type;
+
+       if (type >= ARRAY_SIZE(uart_config))
+               type = 0;
+       return uart_config[type].name;
+}
+
+static const struct uart_ops serial8250_pops = {
+       .tx_empty       = serial8250_tx_empty,
+       .set_mctrl      = serial8250_set_mctrl,
+       .get_mctrl      = serial8250_get_mctrl,
+       .stop_tx        = serial8250_stop_tx,
+       .start_tx       = serial8250_start_tx,
+       .throttle       = serial8250_throttle,
+       .unthrottle     = serial8250_unthrottle,
+       .stop_rx        = serial8250_stop_rx,
+       .enable_ms      = serial8250_enable_ms,
+       .break_ctl      = serial8250_break_ctl,
+       .startup        = serial8250_startup,
+       .shutdown       = serial8250_shutdown,
+       .set_termios    = serial8250_set_termios,
+       .set_ldisc      = serial8250_set_ldisc,
+       .pm             = serial8250_pm,
+       .type           = serial8250_type,
+       .release_port   = serial8250_release_port,
+       .request_port   = serial8250_request_port,
+       .config_port    = serial8250_config_port,
+       .verify_port    = serial8250_verify_port,
+#ifdef CONFIG_CONSOLE_POLL
+       .poll_get_char = serial8250_get_poll_char,
+       .poll_put_char = serial8250_put_poll_char,
+#endif
+};
+
+void serial8250_init_port(struct uart_8250_port *up)
+{
+       struct uart_port *port = &up->port;
+
+       spin_lock_init(&port->lock);
+       port->ops = &serial8250_pops;
+
+       up->cur_iotype = 0xFF;
+}
+EXPORT_SYMBOL_GPL(serial8250_init_port);
+
+void serial8250_set_defaults(struct uart_8250_port *up)
+{
+       struct uart_port *port = &up->port;
+
+       if (up->port.flags & UPF_FIXED_TYPE) {
+               unsigned int type = up->port.type;
+
+               if (!up->port.fifosize)
+                       up->port.fifosize = uart_config[type].fifo_size;
+               if (!up->tx_loadsz)
+                       up->tx_loadsz = uart_config[type].tx_loadsz;
+               if (!up->capabilities)
+                       up->capabilities = uart_config[type].flags;
+       }
+
+       set_io_from_upio(port);
+
+       /* default dma handlers */
+       if (up->dma) {
+               if (!up->dma->tx_dma)
+                       up->dma->tx_dma = serial8250_tx_dma;
+               if (!up->dma->rx_dma)
+                       up->dma->rx_dma = serial8250_rx_dma;
+       }
+}
+EXPORT_SYMBOL_GPL(serial8250_set_defaults);
+
+#ifdef CONFIG_SERIAL_8250_CONSOLE
+
+static void serial8250_console_putchar(struct uart_port *port, int ch)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+
+       wait_for_xmitr(up, UART_LSR_THRE);
+       serial_port_out(port, UART_TX, ch);
+}
+
+/*
+ *     Print a string to the serial port trying not to disturb
+ *     any possible real use of the port...
+ *
+ *     The console_lock must be held when we get here.
+ */
+void serial8250_console_write(struct uart_8250_port *up, const char *s,
+                             unsigned int count)
+{
+       struct uart_port *port = &up->port;
+       unsigned long flags;
+       unsigned int ier;
+       int locked = 1;
+
+       touch_nmi_watchdog();
+
+       serial8250_rpm_get(up);
+
+       if (port->sysrq)
+               locked = 0;
+       else if (oops_in_progress)
+               locked = spin_trylock_irqsave(&port->lock, flags);
+       else
+               spin_lock_irqsave(&port->lock, flags);
+
+       /*
+        *      First save the IER then disable the interrupts
+        */
+       ier = serial_port_in(port, UART_IER);
+
+       if (up->capabilities & UART_CAP_UUE)
+               serial_port_out(port, UART_IER, UART_IER_UUE);
+       else
+               serial_port_out(port, UART_IER, 0);
+
+       /* check scratch reg to see if port powered off during system sleep */
+       if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) {
+               struct ktermios termios;
+               unsigned int baud, quot, frac = 0;
+
+               termios.c_cflag = port->cons->cflag;
+               if (port->state->port.tty && termios.c_cflag == 0)
+                       termios.c_cflag = port->state->port.tty->termios.c_cflag;
+
+               baud = uart_get_baud_rate(port, &termios, NULL,
+                                         port->uartclk / 16 / 0xffff,
+                                         port->uartclk / 16);
+               quot = serial8250_get_divisor(up, baud, &frac);
+
+               serial8250_set_divisor(port, baud, quot, frac);
+               serial_port_out(port, UART_LCR, up->lcr);
+               serial_port_out(port, UART_MCR, UART_MCR_DTR | UART_MCR_RTS);
+
+               up->canary = 0;
+       }
+
+       uart_console_write(port, s, count, serial8250_console_putchar);
+
+       /*
+        *      Finally, wait for transmitter to become empty
+        *      and restore the IER
+        */
+       wait_for_xmitr(up, BOTH_EMPTY);
+       serial_port_out(port, UART_IER, ier);
+
+       /*
+        *      The receive handling will happen properly because the
+        *      receive ready bit will still be set; it is not cleared
+        *      on read.  However, modem control will not, we must
+        *      call it if we have saved something in the saved flags
+        *      while processing with interrupts off.
+        */
+       if (up->msr_saved_flags)
+               serial8250_modem_status(up);
+
+       if (locked)
+               spin_unlock_irqrestore(&port->lock, flags);
+       serial8250_rpm_put(up);
+}
+
+static unsigned int probe_baud(struct uart_port *port)
+{
+       unsigned char lcr, dll, dlm;
+       unsigned int quot;
+
+       lcr = serial_port_in(port, UART_LCR);
+       serial_port_out(port, UART_LCR, lcr | UART_LCR_DLAB);
+       dll = serial_port_in(port, UART_DLL);
+       dlm = serial_port_in(port, UART_DLM);
+       serial_port_out(port, UART_LCR, lcr);
+
+       quot = (dlm << 8) | dll;
+       return (port->uartclk / 16) / quot;
+}
+
+int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
+{
+       int baud = 9600;
+       int bits = 8;
+       int parity = 'n';
+       int flow = 'n';
+
+       if (!port->iobase && !port->membase)
+               return -ENODEV;
+
+       if (options)
+               uart_parse_options(options, &baud, &parity, &bits, &flow);
+       else if (probe)
+               baud = probe_baud(port);
+
+       return uart_set_options(port, port->cons, baud, parity, bits, flow);
+}
+
+#endif /* CONFIG_SERIAL_8250_CONSOLE */
index 706295913c3451e0bea1ce20081e1d0b009ca682..39c6d2277570bcacef38c09fd8203ae8b6793ccd 100644 (file)
@@ -2,10 +2,11 @@
 # Makefile for the 8250 serial device drivers.
 #
 
-obj-$(CONFIG_SERIAL_8250)              += 8250.o
+obj-$(CONFIG_SERIAL_8250)              += 8250.o 8250_base.o
 8250-y                                 := 8250_core.o
 8250-$(CONFIG_SERIAL_8250_PNP)         += 8250_pnp.o
-8250-$(CONFIG_SERIAL_8250_DMA)         += 8250_dma.o
+8250_base-y                            := 8250_port.o
+8250_base-$(CONFIG_SERIAL_8250_DMA)    += 8250_dma.o
 obj-$(CONFIG_SERIAL_8250_GSC)          += 8250_gsc.o
 obj-$(CONFIG_SERIAL_8250_PCI)          += 8250_pci.o
 obj-$(CONFIG_SERIAL_8250_HP300)                += 8250_hp300.o
index ba82c07feb95cbe8eb9e2362f49e4eadc5fcf04d..7f156bde38d989d0784bb7171e529bb84c007ac9 100644 (file)
@@ -152,6 +152,11 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir);
 unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr);
 void serial8250_tx_chars(struct uart_8250_port *up);
 unsigned int serial8250_modem_status(struct uart_8250_port *up);
+void serial8250_init_port(struct uart_8250_port *up);
+void serial8250_set_defaults(struct uart_8250_port *up);
+void serial8250_console_write(struct uart_8250_port *up, const char *s,
+                             unsigned int count);
+int serial8250_console_setup(struct uart_port *port, char *options, bool probe);
 
 extern void serial8250_set_isa_configurator(void (*v)
                                        (int port, struct uart_port *up,