[PATCH] atmel_serial: Pass fixed register mappings through platform_data

In order to initialize the serial console early, the atmel_serial
driver had to do a hack where it compared the physical address of the
port with an address known to be permanently mapped, and used it as a
virtual address. This got around the limitation that ioremap() isn't
always available when the console is being initalized.

This patch removes that hack and replaces it with a new "regs" field
in struct atmel_uart_data that the board-specific code can initialize
to a fixed virtual mapping for platform devices where this is possible.
It also initializes the DBGU's regs field with the address the driver
used to check against.

On AVR32, the "regs" field is initialized from the physical base
address when this it can be accessed through a permanently 1:1 mapped
segment, i.e. the P4 segment.

If regs is NULL, the console initialization is delayed until the "real"
driver is up and running and ioremap() can be used.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 27 insertions, 6 deletions

diff --git a/arch/avr32/mach-at32ap/at32ap7000.c b/arch/avr32/mach-at32ap/at32ap7000.c
index 05d1296bd7b2..3dd305875087 100644
--- a/arch/avr32/mach-at32ap/at32ap7000.c
+++ b/arch/avr32/mach-at32ap/at32ap7000.c
@@ -523,32 +523,48 @@ void __init at32_add_system_devices(void)
  *  USART
  * -------------------------------------------------------------------- */
 
+static struct atmel_uart_data atmel_usart0_data = {
+        .use_dma_tx     = 1,
+        .use_dma_rx     = 1,
+};
 static struct resource atmel_usart0_resource[] = {
         PBMEM(0xffe00c00),
         IRQ(7),
 };
-DEFINE_DEV(atmel_usart, 0);
+DEFINE_DEV_DATA(atmel_usart, 0);
 DEV_CLK(usart, atmel_usart0, pba, 4);
 
+static struct atmel_uart_data atmel_usart1_data = {
+        .use_dma_tx     = 1,
+        .use_dma_rx     = 1,
+};
 static struct resource atmel_usart1_resource[] = {
         PBMEM(0xffe01000),
         IRQ(7),
 };
-DEFINE_DEV(atmel_usart, 1);
+DEFINE_DEV_DATA(atmel_usart, 1);
 DEV_CLK(usart, atmel_usart1, pba, 4);
 
+static struct atmel_uart_data atmel_usart2_data = {
+        .use_dma_tx     = 1,
+        .use_dma_rx     = 1,
+};
 static struct resource atmel_usart2_resource[] = {
         PBMEM(0xffe01400),
         IRQ(8),
 };
-DEFINE_DEV(atmel_usart, 2);
+DEFINE_DEV_DATA(atmel_usart, 2);
 DEV_CLK(usart, atmel_usart2, pba, 5);
 
+static struct atmel_uart_data atmel_usart3_data = {
+        .use_dma_tx     = 1,
+        .use_dma_rx     = 1,
+};
 static struct resource atmel_usart3_resource[] = {
         PBMEM(0xffe01800),
         IRQ(9),
 };
-DEFINE_DEV(atmel_usart, 3);
+DEFINE_DEV_DATA(atmel_usart, 3);
 DEV_CLK(usart, atmel_usart3, pba, 6);
 
 static inline void configure_usart0_pins(void)
@@ -597,8 +613,13 @@ static struct platform_device *setup_usart(unsigned int id)
                 configure_usart3_pins();
                 break;
         default:
-                pdev = NULL;
-                break;
+                return NULL;
+        }
+
+        if (PXSEG(pdev->resource[0].start) == P4SEG) {
+                /* Addresses in the P4 segment are permanently mapped 1:1 */
+                struct atmel_uart_data *data = pdev->dev.platform_data;
+                data->regs = (void __iomem *)pdev->resource[0].start;
         }
 
         return pdev;