debug kernel for dump message

We cannot get any information about the issue, since the console cannot be enabled. Now we introduce two ways to get the log info.

1. Using XDB

a) Find the line ” c0574960 b __log_buf” in the file System.map in the build root folder

b) XDB load the log buf from the address c0574960

Note: the address may change after rebuilding the kernel.

2. Using the Low Level debug

a) Enable the Low Level debug in the menuconfig

Kernel hacking --->

[*] Kernel low-level debugging functions

b) Add the code (the red lines) in the file kernel/printk.c

extern void printch(char c);

static void emit_log_char(char c)

{

LOG_BUF(log_end) = c;

log_end++;

if (log_end - log_start > log_buf_len)

log_start = log_end - log_buf_len;

if (log_end - con_start > log_buf_len)

con_start = log_end - log_buf_len;

if (logged_chars <>

logged_chars++;

printch(c);

}

c) Use the new kernel, then you can get the uart info.

Note: if it cannot work, please make sure in the file -- include/asm-arm/arch-pxa/debug-macro.S, there is the right map for UART registers.