全志平台Uboot和内核打开串口日志的方法

uboot阶段日志信息的打开方法：

t7\lichee\brandy\u-boot-2014.07\include\common.h

#define DEBUG //添加这个语句
#ifdef DEBUG
#define _DEBUG 1
#else
#define _DEBUG 0
#endif

t7\lichee\brandy\u-boot-2014.07\include\mydebug.h

t7\lichee\brandy\u-boot-2014.07\include\configs\sun8iw17p1.h

t7\lichee\brandy\u-boot-2014.07\board\sunxi\common\debug_mode.c

原因：

t7\lichee\brandy\u-boot-2014.07\common\board_f.c

t7\lichee\brandy\u-boot-2014.07\common\console.c

/* Called before relocation - use serial functions */
int console_init_f(void)
{
	gd->have_console = 1;
	int dram_size;
	uint debug_buf_base= 0;
	uint offset = 0, i = 0;
	uint cpu_buf_size[MAX_CPU_CNT] = \
		{CPU0_BUF_SIZE,CPU1_BUF_SIZE,CPU2_BUF_SIZE,CPU3_BUF_SIZE};

#ifdef CONFIG_SILENT_CONSOLE
	if (getenv("silent") != NULL)
		gd->flags |= GD_FLG_SILENT;
#endif
	print_pre_console_buffer();
	//if it is not boot mode, set debug enable
	if(uboot_spare_head.boot_data.work_mode != WORK_MODE_BOOT)
		return 0;
	//if the dram size is 0, set debug enable
	dram_size = uboot_spare_head.boot_data.dram_scan_size;
	if (!dram_size)
		return 0;

	//if user input 's', set debug enable
    //这里是输入s字符将是终端shell模式
	if (uboot_spare_head.boot_ext[0].data[1] == 's') {
		gd->force_shell = 1;
		return 0;
	}
	//if user selete, set debug enable
	//maybe: user set sysconfig
	//maybe: user press keyboard 'd' or 's'
	//'d': only show debug information
    //输入字符d是debug信息显示模式，修改这里即可。这里直接返回即可打开串口调试信息
	debug_level = uboot_spare_head.boot_ext[0].data[3];
	if (debug_level)
	{
		return 0;
	}

	debug_buf_base = (CONFIG_SYS_SDRAM_BASE + dram_size * 1024 * 1024 - CONFIG_SUNXI_DEBUG_BUF_SIZE);
	memset((void*)debug_buf_base, 0, CONFIG_SUNXI_DEBUG_BUF_SIZE);

	offset = debug_buf_base;
	for(i = 0; i < MAX_CPU_CNT; i++)
	{
		debug_info[i].debug_addr = offset;
		debug_info[i].max_len = cpu_buf_size[i];
		offset += cpu_buf_size[i];
	}
	debug_level = 0;

	return 0;
}