Uboot根据读写eeprom启动标记，设置不同bootcmd和bootargs启动参数

来源：互联网发布：招聘淘宝编辑：程序博客网时间：2024/04/29 21:00

要实现此功能大体上分如下步骤：

# 第一，uboot读写eeprom，根据读到的值x （x = [ 0、1、2、3、... ...]）组成（bootcmd<x>, bootargs<x>）；然后获取这组值，来设置bootcmd和bootargs。

# 第二，pc机端把（bootcmd<x>, bootargs<x>）等uboot参数写入到文本文件中，最终生成正确的二进制文件；之后和uboot镜像合成带参数区的bootloader。

代码实现步骤：

# 第一步、在common/main.c文件的main_loop函数中

在以下三行的代码前
s = getenv ("bootcmd");

debug ("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");
添加如下代码：

static int Set_Boot_Param (unsigned char i2c_device_chip, unsigned char rmii);// 省略... ...#define CONFIG_BOOT_CTL#ifdef CONFIG_BOOT_CTL{Set_Boot_Param (i2c_device_chip, rmii);}#endif /* CONFIG_BOOT_CTL *//* --------------------------------------------------- */s = getenv ("bootcmd");debug ("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");if (bootdelay >= 0 && s && !abortboot (bootdelay)) {// 省略... ...static int Set_Boot_Param (unsigned char i2c_device_chip, unsigned char rmii){uchar flags[8];uchar mac[18];unsigned int offset;char *p_bootcmdx;char *p_bootargsx;char bootcmd_name[16];char bootargs_name[16];char bootargsbuf[512];/* delete bootcmd and bootarg, if exist */if (getenv ("bootcmd") ||getenv ("bootargs")){setenv ("bootcmd", NULL);setenv ("bootargs", NULL);saveenv ();}/* reset flags */memset (flags, 0, sizeof (flags));memset (mac, 0, sizeof (mac));/* get 8 chars from eeprom */eeprom_read_flags (flags, sizeof (flags), i2c_device_chip);eeprom_read_mac (mac, sizeof (mac), i2c_device_chip);/* reset bootcmd_name & bootargs_name & bootargsbuf */memset (bootcmd_name, 0, sizeof (bootcmd_name));memset (bootargs_name, 0, sizeof (bootargs_name));memset (bootargsbuf, 0, sizeof (bootargsbuf));sprintf (bootcmd_name, "bootcmd%d", flags[0]);sprintf (bootargs_name, "bootargs%d", flags[0]);p_bootcmdx = getenv (bootcmd_name);p_bootargsx = getenv (bootargs_name);if ((NULL == p_bootcmdx) || (NULL == p_bootargsx)){p_bootcmdx = getenv ("bootcmd0");p_bootargsx = getenv ("bootargs0");/* write eeprom *///...}if ((NULL != p_bootcmdx) && (NULL != p_bootargsx)){sprintf (bootargsbuf, "flags=%02x.%02x.%02x.%02x.%02x.%02x.%02x.%02x ",flags[0], flags[1], flags[2], flags[3], flags[4], flags[5], flags[6], flags[7]);strcat (bootargsbuf, p_bootargsx);sprintf (bootargsbuf, "%s rmii=%d", bootargsbuf, rmii);strcat (bootargsbuf, " nwhwconf=device:eth0,hwaddr:");strcat (bootargsbuf, mac);setenv("bootcmd", p_bootcmdx);setenv("bootargs", bootargsbuf);}#if 0printf ("########\n");printf ("%s=%s", bootcmd_name, p_bootcmdx);printf ("\n\n");printf ("%s=%s", bootargs_name, bootargsbuf);printf ("\n########\n");#endifreturn 0;}

# 使用说明：
1、板子启动之后设置如下的bootcmd<x>和bootargs<x>组合：
第0组
bootcmd0=""
bootargs0=""
第1组
bootcmd1=""
bootargs1=""

imw 51 0.2 0 1 # 使用第0组
imw 51 0.2 1 1 # 使用第1组

2、若没有设置，则需手动设置bootcmd和bootargs。

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注意事项：
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如果执行save操作，一定要在它之前执行setenv bootcmd; setenv bootargs; save;
否则，设置的bootcmd和bootargs字符串会出现错位。

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