原理：使用cpuid生成mac地址

1、修改u-boot/net/eth_common.c里的eth_env_set_enetaddr函数为：

int eth_env_set_enetaddr(const char *name, const uchar *enetaddr)
{char buf[ARP_HLEN_ASCII + 1];sprintf(buf, "%pM", enetaddr);return env_set(name, buf);
}

2、修改u-boot/board/firefly/firefly-rk3288/firefly-rk3288.c里的setup_macaddr函数为：

void setup_macaddr(void)
{
#if CONFIG_IS_ENABLED(CMD_NET)int ret;const char *cpuid = env_get("cpuid#");u8 hash[SHA256_SUM_LEN];int size = sizeof(hash);u8 mac_addr[6];u8 mac1_addr[6];/* Only generate a MAC address, if none is set in the environment *///if (env_get("ethaddr"))//      return;if (!cpuid) {debug("%s: could not retrieve 'cpuid#'\n", __func__);return;}ret = hash_block("sha256", (void *)cpuid, strlen(cpuid), hash, &size);if (ret) {debug("%s: failed to calculate SHA256\n", __func__);return;}/* Copy 6 bytes of the hash to base the MAC address on */memcpy(mac_addr, hash, 6);/* Make this a valid MAC address and set it */mac_addr[0] &= 0xfe;  /* clear multicast bit */mac_addr[0] |= 0x02;  /* set local assignment bit (IEEE802) */eth_env_set_enetaddr("ethaddr", mac_addr);memcpy(mac1_addr, hash, 6);mac1_addr[5]++;eth_env_set_enetaddr("eth1addr", mac1_addr);
#endifreturn;
}

4、在u-boot/include/common.h里添加如下函数定义（我加在45行）：

void setup_macaddr(void);

5、在u-boot/common/autoboot.c的autoboot_command函数入口，调用setup_macaddr函数：

void autoboot_command(const char *s)
{debug("### main_loop: bootcmd=\"%s\"\n", s ? s : "<UNDEFINED>");setup_macaddr();if (stored_bootdelay != -1 && s && !abortboot(stored_bootdelay)) {
#if defined(CONFIG_AUTOBOOT_KEYED) && !defined(CONFIG_AUTOBOOT_KEYED_CTRLC)int prev = disable_ctrlc(1);    /* disable Control C checking */
#endifrun_command_list(s, -1, 0);autoboot_command_fail_handle();#if defined(CONFIG_AUTOBOOT_KEYED) && !defined(CONFIG_AUTOBOOT_KEYED_CTRLC)disable_ctrlc(prev);    /* restore Control C checking */
#endif}#ifdef CONFIG_MENUKEYif (menukey == CONFIG_MENUKEY) {s = env_get("menucmd");if (s)run_command_list(s, -1, 0);}
#endif /* CONFIG_MENUKEY */
}

结束。