2 * Driver for AMBA serial ports
4 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
6 * Copyright 1999 ARM Limited
7 * Copyright (C) 2000 Deep Blue Solutions Ltd.
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 * This is a generic driver for ARM AMBA-type serial ports. They
24 * have a lot of 16550-like features, but are not register compatible.
25 * Note that although they do have CTS, DCD and DSR inputs, they do
26 * not have an RI input, nor do they have DTR or RTS outputs. If
27 * required, these have to be supplied via some other means (eg, GPIO)
28 * and hooked into this driver.
31 #if defined(CONFIG_SERIAL_AMBA_PL010_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
35 #include <linux/module.h>
36 #include <linux/ioport.h>
37 #include <linux/init.h>
38 #include <linux/console.h>
39 #include <linux/sysrq.h>
40 #include <linux/device.h>
41 #include <linux/tty.h>
42 #include <linux/tty_flip.h>
43 #include <linux/serial_core.h>
44 #include <linux/serial.h>
45 #include <linux/amba/bus.h>
46 #include <linux/amba/serial.h>
47 #include <linux/clk.h>
48 #include <linux/slab.h>
53 #define SERIAL_AMBA_MAJOR 204
54 #define SERIAL_AMBA_MINOR 16
55 #define SERIAL_AMBA_NR UART_NR
57 #define AMBA_ISR_PASS_LIMIT 256
59 #define UART_RX_DATA(s) (((s) & UART01x_FR_RXFE) == 0)
60 #define UART_TX_READY(s) (((s) & UART01x_FR_TXFF) == 0)
62 #define UART_DUMMY_RSR_RX 256
63 #define UART_PORT_SIZE 64
66 * We wrap our port structure around the generic uart_port.
68 struct uart_amba_port {
69 struct uart_port port;
71 struct amba_device *dev;
72 struct amba_pl010_data *data;
73 unsigned int old_status;
76 static void pl010_stop_tx(struct uart_port *port)
78 struct uart_amba_port *uap = (struct uart_amba_port *)port;
81 cr = readb(uap->port.membase + UART010_CR);
82 cr &= ~UART010_CR_TIE;
83 writel(cr, uap->port.membase + UART010_CR);
86 static void pl010_start_tx(struct uart_port *port)
88 struct uart_amba_port *uap = (struct uart_amba_port *)port;
91 cr = readb(uap->port.membase + UART010_CR);
93 writel(cr, uap->port.membase + UART010_CR);
96 static void pl010_stop_rx(struct uart_port *port)
98 struct uart_amba_port *uap = (struct uart_amba_port *)port;
101 cr = readb(uap->port.membase + UART010_CR);
102 cr &= ~(UART010_CR_RIE | UART010_CR_RTIE);
103 writel(cr, uap->port.membase + UART010_CR);
106 static void pl010_enable_ms(struct uart_port *port)
108 struct uart_amba_port *uap = (struct uart_amba_port *)port;
111 cr = readb(uap->port.membase + UART010_CR);
112 cr |= UART010_CR_MSIE;
113 writel(cr, uap->port.membase + UART010_CR);
116 static void pl010_rx_chars(struct uart_amba_port *uap)
118 unsigned int status, ch, flag, rsr, max_count = 256;
120 status = readb(uap->port.membase + UART01x_FR);
121 while (UART_RX_DATA(status) && max_count--) {
122 ch = readb(uap->port.membase + UART01x_DR);
125 uap->port.icount.rx++;
128 * Note that the error handling code is
129 * out of the main execution path
131 rsr = readb(uap->port.membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
132 if (unlikely(rsr & UART01x_RSR_ANY)) {
133 writel(0, uap->port.membase + UART01x_ECR);
135 if (rsr & UART01x_RSR_BE) {
136 rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
137 uap->port.icount.brk++;
138 if (uart_handle_break(&uap->port))
140 } else if (rsr & UART01x_RSR_PE)
141 uap->port.icount.parity++;
142 else if (rsr & UART01x_RSR_FE)
143 uap->port.icount.frame++;
144 if (rsr & UART01x_RSR_OE)
145 uap->port.icount.overrun++;
147 rsr &= uap->port.read_status_mask;
149 if (rsr & UART01x_RSR_BE)
151 else if (rsr & UART01x_RSR_PE)
153 else if (rsr & UART01x_RSR_FE)
157 if (uart_handle_sysrq_char(&uap->port, ch))
160 uart_insert_char(&uap->port, rsr, UART01x_RSR_OE, ch, flag);
163 status = readb(uap->port.membase + UART01x_FR);
165 spin_unlock(&uap->port.lock);
166 tty_flip_buffer_push(&uap->port.state->port);
167 spin_lock(&uap->port.lock);
170 static void pl010_tx_chars(struct uart_amba_port *uap)
172 struct circ_buf *xmit = &uap->port.state->xmit;
175 if (uap->port.x_char) {
176 writel(uap->port.x_char, uap->port.membase + UART01x_DR);
177 uap->port.icount.tx++;
178 uap->port.x_char = 0;
181 if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
182 pl010_stop_tx(&uap->port);
186 count = uap->port.fifosize >> 1;
188 writel(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
189 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
190 uap->port.icount.tx++;
191 if (uart_circ_empty(xmit))
193 } while (--count > 0);
195 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
196 uart_write_wakeup(&uap->port);
198 if (uart_circ_empty(xmit))
199 pl010_stop_tx(&uap->port);
202 static void pl010_modem_status(struct uart_amba_port *uap)
204 unsigned int status, delta;
206 writel(0, uap->port.membase + UART010_ICR);
208 status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
210 delta = status ^ uap->old_status;
211 uap->old_status = status;
216 if (delta & UART01x_FR_DCD)
217 uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
219 if (delta & UART01x_FR_DSR)
220 uap->port.icount.dsr++;
222 if (delta & UART01x_FR_CTS)
223 uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
225 wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
228 static irqreturn_t pl010_int(int irq, void *dev_id)
230 struct uart_amba_port *uap = dev_id;
231 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
234 spin_lock(&uap->port.lock);
236 status = readb(uap->port.membase + UART010_IIR);
239 if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
241 if (status & UART010_IIR_MIS)
242 pl010_modem_status(uap);
243 if (status & UART010_IIR_TIS)
246 if (pass_counter-- == 0)
249 status = readb(uap->port.membase + UART010_IIR);
250 } while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
255 spin_unlock(&uap->port.lock);
257 return IRQ_RETVAL(handled);
260 static unsigned int pl010_tx_empty(struct uart_port *port)
262 struct uart_amba_port *uap = (struct uart_amba_port *)port;
263 unsigned int status = readb(uap->port.membase + UART01x_FR);
264 return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
267 static unsigned int pl010_get_mctrl(struct uart_port *port)
269 struct uart_amba_port *uap = (struct uart_amba_port *)port;
270 unsigned int result = 0;
273 status = readb(uap->port.membase + UART01x_FR);
274 if (status & UART01x_FR_DCD)
276 if (status & UART01x_FR_DSR)
278 if (status & UART01x_FR_CTS)
284 static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
286 struct uart_amba_port *uap = (struct uart_amba_port *)port;
289 uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
292 static void pl010_break_ctl(struct uart_port *port, int break_state)
294 struct uart_amba_port *uap = (struct uart_amba_port *)port;
298 spin_lock_irqsave(&uap->port.lock, flags);
299 lcr_h = readb(uap->port.membase + UART010_LCRH);
300 if (break_state == -1)
301 lcr_h |= UART01x_LCRH_BRK;
303 lcr_h &= ~UART01x_LCRH_BRK;
304 writel(lcr_h, uap->port.membase + UART010_LCRH);
305 spin_unlock_irqrestore(&uap->port.lock, flags);
308 static int pl010_startup(struct uart_port *port)
310 struct uart_amba_port *uap = (struct uart_amba_port *)port;
314 * Try to enable the clock producer.
316 retval = clk_prepare_enable(uap->clk);
320 uap->port.uartclk = clk_get_rate(uap->clk);
325 retval = request_irq(uap->port.irq, pl010_int, 0, "uart-pl010", uap);
330 * initialise the old status of the modem signals
332 uap->old_status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
335 * Finally, enable interrupts
337 writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
338 uap->port.membase + UART010_CR);
343 clk_disable_unprepare(uap->clk);
348 static void pl010_shutdown(struct uart_port *port)
350 struct uart_amba_port *uap = (struct uart_amba_port *)port;
355 free_irq(uap->port.irq, uap);
358 * disable all interrupts, disable the port
360 writel(0, uap->port.membase + UART010_CR);
362 /* disable break condition and fifos */
363 writel(readb(uap->port.membase + UART010_LCRH) &
364 ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
365 uap->port.membase + UART010_LCRH);
368 * Shut down the clock producer
370 clk_disable_unprepare(uap->clk);
374 pl010_set_termios(struct uart_port *port, struct ktermios *termios,
375 struct ktermios *old)
377 struct uart_amba_port *uap = (struct uart_amba_port *)port;
378 unsigned int lcr_h, old_cr;
380 unsigned int baud, quot;
383 * Ask the core to calculate the divisor for us.
385 baud = uart_get_baud_rate(port, termios, old, 0, uap->port.uartclk/16);
386 quot = uart_get_divisor(port, baud);
388 switch (termios->c_cflag & CSIZE) {
390 lcr_h = UART01x_LCRH_WLEN_5;
393 lcr_h = UART01x_LCRH_WLEN_6;
396 lcr_h = UART01x_LCRH_WLEN_7;
399 lcr_h = UART01x_LCRH_WLEN_8;
402 if (termios->c_cflag & CSTOPB)
403 lcr_h |= UART01x_LCRH_STP2;
404 if (termios->c_cflag & PARENB) {
405 lcr_h |= UART01x_LCRH_PEN;
406 if (!(termios->c_cflag & PARODD))
407 lcr_h |= UART01x_LCRH_EPS;
409 if (uap->port.fifosize > 1)
410 lcr_h |= UART01x_LCRH_FEN;
412 spin_lock_irqsave(&uap->port.lock, flags);
415 * Update the per-port timeout.
417 uart_update_timeout(port, termios->c_cflag, baud);
419 uap->port.read_status_mask = UART01x_RSR_OE;
420 if (termios->c_iflag & INPCK)
421 uap->port.read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
422 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
423 uap->port.read_status_mask |= UART01x_RSR_BE;
426 * Characters to ignore
428 uap->port.ignore_status_mask = 0;
429 if (termios->c_iflag & IGNPAR)
430 uap->port.ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
431 if (termios->c_iflag & IGNBRK) {
432 uap->port.ignore_status_mask |= UART01x_RSR_BE;
434 * If we're ignoring parity and break indicators,
435 * ignore overruns too (for real raw support).
437 if (termios->c_iflag & IGNPAR)
438 uap->port.ignore_status_mask |= UART01x_RSR_OE;
442 * Ignore all characters if CREAD is not set.
444 if ((termios->c_cflag & CREAD) == 0)
445 uap->port.ignore_status_mask |= UART_DUMMY_RSR_RX;
447 /* first, disable everything */
448 old_cr = readb(uap->port.membase + UART010_CR) & ~UART010_CR_MSIE;
450 if (UART_ENABLE_MS(port, termios->c_cflag))
451 old_cr |= UART010_CR_MSIE;
453 writel(0, uap->port.membase + UART010_CR);
457 writel((quot & 0xf00) >> 8, uap->port.membase + UART010_LCRM);
458 writel(quot & 0xff, uap->port.membase + UART010_LCRL);
461 * ----------v----------v----------v----------v-----
462 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
463 * ----------^----------^----------^----------^-----
465 writel(lcr_h, uap->port.membase + UART010_LCRH);
466 writel(old_cr, uap->port.membase + UART010_CR);
468 spin_unlock_irqrestore(&uap->port.lock, flags);
471 static void pl010_set_ldisc(struct uart_port *port, int new)
474 port->flags |= UPF_HARDPPS_CD;
475 pl010_enable_ms(port);
477 port->flags &= ~UPF_HARDPPS_CD;
480 static const char *pl010_type(struct uart_port *port)
482 return port->type == PORT_AMBA ? "AMBA" : NULL;
486 * Release the memory region(s) being used by 'port'
488 static void pl010_release_port(struct uart_port *port)
490 release_mem_region(port->mapbase, UART_PORT_SIZE);
494 * Request the memory region(s) being used by 'port'
496 static int pl010_request_port(struct uart_port *port)
498 return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
499 != NULL ? 0 : -EBUSY;
503 * Configure/autoconfigure the port.
505 static void pl010_config_port(struct uart_port *port, int flags)
507 if (flags & UART_CONFIG_TYPE) {
508 port->type = PORT_AMBA;
509 pl010_request_port(port);
514 * verify the new serial_struct (for TIOCSSERIAL).
516 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
519 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
521 if (ser->irq < 0 || ser->irq >= nr_irqs)
523 if (ser->baud_base < 9600)
528 static struct uart_ops amba_pl010_pops = {
529 .tx_empty = pl010_tx_empty,
530 .set_mctrl = pl010_set_mctrl,
531 .get_mctrl = pl010_get_mctrl,
532 .stop_tx = pl010_stop_tx,
533 .start_tx = pl010_start_tx,
534 .stop_rx = pl010_stop_rx,
535 .enable_ms = pl010_enable_ms,
536 .break_ctl = pl010_break_ctl,
537 .startup = pl010_startup,
538 .shutdown = pl010_shutdown,
539 .set_termios = pl010_set_termios,
540 .set_ldisc = pl010_set_ldisc,
542 .release_port = pl010_release_port,
543 .request_port = pl010_request_port,
544 .config_port = pl010_config_port,
545 .verify_port = pl010_verify_port,
548 static struct uart_amba_port *amba_ports[UART_NR];
550 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
552 static void pl010_console_putchar(struct uart_port *port, int ch)
554 struct uart_amba_port *uap = (struct uart_amba_port *)port;
558 status = readb(uap->port.membase + UART01x_FR);
560 } while (!UART_TX_READY(status));
561 writel(ch, uap->port.membase + UART01x_DR);
565 pl010_console_write(struct console *co, const char *s, unsigned int count)
567 struct uart_amba_port *uap = amba_ports[co->index];
568 unsigned int status, old_cr;
570 clk_enable(uap->clk);
573 * First save the CR then disable the interrupts
575 old_cr = readb(uap->port.membase + UART010_CR);
576 writel(UART01x_CR_UARTEN, uap->port.membase + UART010_CR);
578 uart_console_write(&uap->port, s, count, pl010_console_putchar);
581 * Finally, wait for transmitter to become empty
582 * and restore the TCR
585 status = readb(uap->port.membase + UART01x_FR);
587 } while (status & UART01x_FR_BUSY);
588 writel(old_cr, uap->port.membase + UART010_CR);
590 clk_disable(uap->clk);
594 pl010_console_get_options(struct uart_amba_port *uap, int *baud,
595 int *parity, int *bits)
597 if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) {
598 unsigned int lcr_h, quot;
599 lcr_h = readb(uap->port.membase + UART010_LCRH);
602 if (lcr_h & UART01x_LCRH_PEN) {
603 if (lcr_h & UART01x_LCRH_EPS)
609 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
614 quot = readb(uap->port.membase + UART010_LCRL) |
615 readb(uap->port.membase + UART010_LCRM) << 8;
616 *baud = uap->port.uartclk / (16 * (quot + 1));
620 static int __init pl010_console_setup(struct console *co, char *options)
622 struct uart_amba_port *uap;
630 * Check whether an invalid uart number has been specified, and
631 * if so, search for the first available port that does have
634 if (co->index >= UART_NR)
636 uap = amba_ports[co->index];
640 ret = clk_prepare(uap->clk);
644 uap->port.uartclk = clk_get_rate(uap->clk);
647 uart_parse_options(options, &baud, &parity, &bits, &flow);
649 pl010_console_get_options(uap, &baud, &parity, &bits);
651 return uart_set_options(&uap->port, co, baud, parity, bits, flow);
654 static struct uart_driver amba_reg;
655 static struct console amba_console = {
657 .write = pl010_console_write,
658 .device = uart_console_device,
659 .setup = pl010_console_setup,
660 .flags = CON_PRINTBUFFER,
665 #define AMBA_CONSOLE &amba_console
667 #define AMBA_CONSOLE NULL
670 static struct uart_driver amba_reg = {
671 .owner = THIS_MODULE,
672 .driver_name = "ttyAM",
674 .major = SERIAL_AMBA_MAJOR,
675 .minor = SERIAL_AMBA_MINOR,
677 .cons = AMBA_CONSOLE,
680 static int pl010_probe(struct amba_device *dev, const struct amba_id *id)
682 struct uart_amba_port *uap;
686 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
687 if (amba_ports[i] == NULL)
690 if (i == ARRAY_SIZE(amba_ports))
693 uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
698 base = devm_ioremap(&dev->dev, dev->res.start,
699 resource_size(&dev->res));
703 uap->clk = devm_clk_get(&dev->dev, NULL);
704 if (IS_ERR(uap->clk))
705 return PTR_ERR(uap->clk);
707 uap->port.dev = &dev->dev;
708 uap->port.mapbase = dev->res.start;
709 uap->port.membase = base;
710 uap->port.iotype = UPIO_MEM;
711 uap->port.irq = dev->irq[0];
712 uap->port.fifosize = 16;
713 uap->port.ops = &amba_pl010_pops;
714 uap->port.flags = UPF_BOOT_AUTOCONF;
717 uap->data = dev_get_platdata(&dev->dev);
721 amba_set_drvdata(dev, uap);
722 ret = uart_add_one_port(&amba_reg, &uap->port);
724 amba_ports[i] = NULL;
729 static int pl010_remove(struct amba_device *dev)
731 struct uart_amba_port *uap = amba_get_drvdata(dev);
734 uart_remove_one_port(&amba_reg, &uap->port);
736 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
737 if (amba_ports[i] == uap)
738 amba_ports[i] = NULL;
743 #ifdef CONFIG_PM_SLEEP
744 static int pl010_suspend(struct device *dev)
746 struct uart_amba_port *uap = dev_get_drvdata(dev);
749 uart_suspend_port(&amba_reg, &uap->port);
754 static int pl010_resume(struct device *dev)
756 struct uart_amba_port *uap = dev_get_drvdata(dev);
759 uart_resume_port(&amba_reg, &uap->port);
765 static SIMPLE_DEV_PM_OPS(pl010_dev_pm_ops, pl010_suspend, pl010_resume);
767 static struct amba_id pl010_ids[] = {
775 MODULE_DEVICE_TABLE(amba, pl010_ids);
777 static struct amba_driver pl010_driver = {
779 .name = "uart-pl010",
780 .pm = &pl010_dev_pm_ops,
782 .id_table = pl010_ids,
783 .probe = pl010_probe,
784 .remove = pl010_remove,
787 static int __init pl010_init(void)
791 printk(KERN_INFO "Serial: AMBA driver\n");
793 ret = uart_register_driver(&amba_reg);
795 ret = amba_driver_register(&pl010_driver);
797 uart_unregister_driver(&amba_reg);
802 static void __exit pl010_exit(void)
804 amba_driver_unregister(&pl010_driver);
805 uart_unregister_driver(&amba_reg);
808 module_init(pl010_init);
809 module_exit(pl010_exit);
811 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
812 MODULE_DESCRIPTION("ARM AMBA serial port driver");
813 MODULE_LICENSE("GPL");