diff options
| author | Tony Lindgren <tony@atomide.com> | 2010-05-01 04:39:19 +0400 |
|---|---|---|
| committer | Tony Lindgren <tony@atomide.com> | 2010-05-04 04:53:08 +0400 |
| commit | 96554d70775e936e870f61d9523c9bab3fd54ad6 (patch) | |
| tree | 7a3c8f4b40d5753de274226cf7829bbbc9d0eb14 /arch/arm/plat-omap/include/plat/serial.h | |
| parent | daa494958a59638f32b4334155e4c3e1f664c675 (diff) | |
| download | linux-96554d70775e936e870f61d9523c9bab3fd54ad6.tar.xz | |
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>
Diffstat (limited to 'arch/arm/plat-omap/include/plat/serial.h')
| -rw-r--r-- | arch/arm/plat-omap/include/plat/serial.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/arm/plat-omap/include/plat/serial.h b/arch/arm/plat-omap/include/plat/serial.h index 83dce4c4f7e6..42a6318dd305 100644 --- a/arch/arm/plat-omap/include/plat/serial.h +++ b/arch/arm/plat-omap/include/plat/serial.h @@ -15,6 +15,20 @@ #include <linux/init.h> +/* + * Memory entry used for the DEBUG_LL UART configuration. See also + * uncompress.h and debug-macro.S. + * + * Note that using a memory location for storing the UART configuration + * has at least two limitations: + * + * 1. Kernel uncompress code cannot overlap OMAP_UART_INFO as the + * uncompress code could then partially overwrite itself + * 2. We assume printascii is called at least once before paging_init, + * and addruart has a chance to read OMAP_UART_INFO + */ +#define OMAP_UART_INFO (PHYS_OFFSET + 0x3ffc) + /* OMAP1 serial ports */ #define OMAP1_UART1_BASE 0xfffb0000 #define OMAP1_UART2_BASE 0xfffb0800 |