On Tue, Nov 30, 2010 at 05:17:58PM -0800, Greg KH wrote:
> On Mon, Nov 22, 2010 at 02:26:47PM +0000, Jamie Iles wrote:
> > + writeb(value, p->membase + offset);
> > + else
> > + writel(value, p->membase + offset);
> > +
>
> As this is on the "fast path" for writing data out, isn't it going to
> slow down the UPIO_DWAPB users as well?
Yes, that's a fair point. Perhaps I was trying too hard to avoid copy and
paste code! How about this instead?
Jamie
>From 19f6bf46ed0da675e8f98f58b3374634cfe3a7f2 Mon Sep 17 00:00:00 2001
From: Jamie Iles <jamie@xxxxxxxxxxxxx>
Date: Wed, 1 Dec 2010 07:44:37 +0000
Subject: [PATCH] 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.
Signed-off-by: Jamie Iles <jamie@xxxxxxxxxxxxx>
---
drivers/serial/8250.c | 50 ++++++++++++++++++++++++++++++++---------
drivers/serial/serial_core.c | 2 +
include/linux/serial_core.h | 1 +
3 files changed, 42 insertions(+), 11 deletions(-)
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 4d8e14b..df43cc3 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -454,21 +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 = (struct uart_8250_port *)p;
- 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)
@@ -518,6 +537,11 @@ 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;
@@ -536,6 +560,7 @@ 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;
@@ -1581,7 +1606,8 @@ 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
@@ -2476,6 +2502,7 @@ 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;
@@ -2513,6 +2540,7 @@ 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 9ffa5be..143103b 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -2134,6 +2134,7 @@ 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;
@@ -2554,6 +2555,7 @@ 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 212eb4c..8681e7c 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -311,6 +311,7 @@ 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 */
--
1.7.2.3
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
