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

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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>
This commit is contained in:
Tony Lindgren
2010-04-30 17:39:19 -07:00
parent daa494958a
commit 96554d7077
4 changed files with 43 additions and 47 deletions
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21
arch/arm/mach-omap1/include/mach/debug-macro.S
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@@ -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?