omap: Use a memory address for storing the debug port info instead of UART1 scratchpad

This removes the dependency to the UART1 being available for storing
the debug configuration in uncompress.h. This will simplify the
DEBUG_LL UART configuration for boards that may not have UART1, or
have an external UART as it requires only one mapping for DEBUG_LL.

The patch has a few limitations. Basically now we're assuming that
the kernel uncompress code won't overlap with OMAP_UART_INFO. We also
assume the printascii is called at least once before paging_init in
order for addruart to have a chance to read the UART setup from
OMAP_UART_INFO.

As suggested by Cyril Chemparathy <cyril@ti.com>,
Vikram Pandita <vikram.pandita@ti.com> and
Kevin Hilman <khilman@deeprootsystems.com>. Based on an earlier
patch posted for Davinci by Cyril Chemparathy <cyril@ti.com>.

Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 6 insertions, 15 deletions

diff --git a/arch/arm/mach-omap1/include/mach/debug-macro.S b/arch/arm/mach-omap1/include/mach/debug-macro.S
index b6d9584544b4..e8a8cf36b7f0 100644
--- a/arch/arm/mach-omap1/include/mach/debug-macro.S
+++ b/arch/arm/mach-omap1/include/mach/debug-macro.S
@@ -13,6 +13,8 @@
 
 #include <linux/serial_reg.h>
 
+#include <asm/memory.h>
+
 #include <plat/serial.h>
 
                 .pushsection .data
@@ -37,23 +39,12 @@ omap_uart_virt:	.word	0x0
                 cmp     \rx, #0                 @ is port configured?
                 bne     99f                     @ already configured
 
-                /* Check 7XX UART1 scratchpad register for uart to use */
+                /* Check the debug UART configuration set in uncompress.h */
                 mrc     p15, 0, \rx, c1, c0
                 tst     \rx, #1                 @ MMU enabled?
-                moveq   \rx, #0xff000000        @ physical base address
-                movne   \rx, #0xfe000000        @ virtual base
-                orr     \rx, \rx, #0x00fb0000   @ OMAP1UART1
-                ldrb    \rx, [\rx, #(UART_SCR << OMAP7XX_PORT_SHIFT)]
-                cmp     \rx, #0                 @ anything in 7XX scratchpad?
-                bne     10f                     @ found 7XX uart
-
-                /* Check 15xx/16xx UART1 scratchpad register for uart to use */
-                mrc     p15, 0, \rx, c1, c0
-                tst     \rx, #1                 @ MMU enabled?
-                moveq   \rx, #0xff000000        @ physical base address
-                movne   \rx, #0xfe000000        @ virtual base
-                orr     \rx, \rx, #0x00fb0000   @ OMAP1UART1
-                ldrb    \rx, [\rx, #(UART_SCR << OMAP_PORT_SHIFT)]
+                ldreq   \rx, =OMAP_UART_INFO
+                ldrne   \rx, =__phys_to_virt(OMAP_UART_INFO)
+                ldr     \rx, [\rx, #0]
 
                 /* Select the UART to use based on the UART1 scratchpad value */
 10:             cmp     \rx, #0                 @ no port configured?