8250: add a UPIO_DWAPB32 for 32 bit accesses

Some platforms contain a Synopsys DesignWare APB UART that is attached
to a 32-bit APB bus where sub-word accesses are not allowed. Add a new
IO type (UPIO_DWAPB32) that performs 32 bit acccesses to the UART.

v2:
	- don't test for 32 bit in the output fast path, provide a
	  separate dwabp32_serial_out() function. Refactor
	  dwabp_serial_out() so that we can reuse the LCR saving
	  code.
v3:
	- rebased on top of "8250: use container_of() instead of
	  casting"

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 0b4ce47d987197cac0b3df1f636edfd399dbebd2..9839199c1d1d06160dfa062e8e5e77ce069b397e 100644 (file)
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -454,22 +454,40 @@ static void tsi_serial_out(struct uart_port *p, int offset, int value)
                writeb(value, p->membase + offset);
 }
 
+/* Save the LCR value so it can be re-written when a Busy Detect IRQ occurs. */
+static inline void dwapb_save_out_value(struct uart_port *p, int offset,
+                                       int value)
+{
+       struct uart_8250_port *up =
+               container_of(p, struct uart_8250_port, port);
+
+       if (offset == UART_LCR)
+               up->lcr = value;
+}
+
+/* Read the IER to ensure any interrupt is cleared before returning from ISR. */
+static inline void dwapb_check_clear_ier(struct uart_port *p, int offset)
+{
+       if (offset == UART_TX || offset == UART_IER)
+               p->serial_in(p, UART_IER);
+}
+
 static void dwapb_serial_out(struct uart_port *p, int offset, int value)
 {
        int save_offset = offset;
        offset = map_8250_out_reg(p, offset) << p->regshift;
-       /* Save the LCR value so it can be re-written when a
-        * Busy Detect interrupt occurs. */
-       if (save_offset == UART_LCR) {
-               struct uart_8250_port *up =
-                       container_of(p, struct uart_8250_port, port);
-               up->lcr = value;
-       }
+       dwapb_save_out_value(p, save_offset, value);
        writeb(value, p->membase + offset);
-       /* Read the IER to ensure any interrupt is cleared before
-        * returning from ISR. */
-       if (save_offset == UART_TX || save_offset == UART_IER)
-               value = p->serial_in(p, UART_IER);
+       dwapb_check_clear_ier(p, save_offset);
+}
+
+static void dwapb32_serial_out(struct uart_port *p, int offset, int value)
+{
+       int save_offset = offset;
+       offset = map_8250_out_reg(p, offset) << p->regshift;
+       dwapb_save_out_value(p, save_offset, value);
+       writel(value, p->membase + offset);
+       dwapb_check_clear_ier(p, save_offset);
 }
 
 static unsigned int io_serial_in(struct uart_port *p, int offset)
@@ -520,6 +538,11 @@ static void set_io_from_upio(struct uart_port *p)
                p->serial_out = dwapb_serial_out;
                break;
 
+       case UPIO_DWAPB32:
+               p->serial_in = mem32_serial_in;
+               p->serial_out = dwapb32_serial_out;
+               break;
+
        default:
                p->serial_in = io_serial_in;
                p->serial_out = io_serial_out;
@@ -538,6 +561,7 @@ serial_out_sync(struct uart_8250_port *up, int offset, int value)
        case UPIO_MEM32:
        case UPIO_AU:
        case UPIO_DWAPB:
+       case UPIO_DWAPB32:
                p->serial_out(p, offset, value);
                p->serial_in(p, UART_LCR);      /* safe, no side-effects */
                break;
@@ -1587,7 +1611,8 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
                        handled = 1;
 
                        end = NULL;
-               } else if (up->port.iotype == UPIO_DWAPB &&
+               } else if ((up->port.iotype == UPIO_DWAPB ||
+                           up->port.iotype == UPIO_DWAPB32) &&
                          (iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
                        /* The DesignWare APB UART has an Busy Detect (0x07)
                         * interrupt meaning an LCR write attempt occured while the
@@ -2492,6 +2517,7 @@ static int serial8250_request_std_resource(struct uart_8250_port *up)
        case UPIO_MEM32:
        case UPIO_MEM:
        case UPIO_DWAPB:
+       case UPIO_DWAPB32:
                if (!up->port.mapbase)
                        break;
 
@@ -2529,6 +2555,7 @@ static void serial8250_release_std_resource(struct uart_8250_port *up)
        case UPIO_MEM32:
        case UPIO_MEM:
        case UPIO_DWAPB:
+       case UPIO_DWAPB32:
                if (!up->port.mapbase)
                        break;
 

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index c4ea14670d4486fc142df31d806c528d2752c238..2835e29298ede2d2fbcc34aed0de17b7da776d2c 100644 (file)
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -2135,6 +2135,7 @@ uart_report_port(struct uart_driver *drv, struct uart_port *port)
        case UPIO_AU:
        case UPIO_TSI:
        case UPIO_DWAPB:
+       case UPIO_DWAPB32:
                snprintf(address, sizeof(address),
                         "MMIO 0x%llx", (unsigned long long)port->mapbase);
                break;
@@ -2555,6 +2556,7 @@ int uart_match_port(struct uart_port *port1, struct uart_port *port2)
        case UPIO_AU:
        case UPIO_TSI:
        case UPIO_DWAPB:
+       case UPIO_DWAPB32:
                return (port1->mapbase == port2->mapbase);
        }
        return 0;

diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 9ff9b7db293bba268cab3c4218f26beda963941a..7a6daf1899956ad99c09ebf0fb4a06eecf67c8f7 100644 (file)
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -314,6 +314,7 @@ struct uart_port {
 #define UPIO_TSI               (5)                     /* Tsi108/109 type IO */
 #define UPIO_DWAPB             (6)                     /* DesignWare APB UART */
 #define UPIO_RM9000            (7)                     /* RM9000 type IO */
+#define UPIO_DWAPB32           (8)                     /* DesignWare APB UART (32 bit accesses) */
 
        unsigned int            read_status_mask;       /* driver specific */
        unsigned int            ignore_status_mask;     /* driver specific */