nand读取指定分区的俩种方式

kernel中直接读取具体mtd

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static int (void)
{
	struct mtd_info *mtd = NULL;
	char buf[8] = {0};
	size_t bytes_read = 0;
	int err = 0;
	
	mtd = get_mtd_device_nm("res");
	if(IS_ERR(mtd))
		return -ENODEV;
	//读取mtd上,偏移0个字节长度,读取长度,实际读取字节数
	err = mtd_read(mtd, 0, sizeof(buf), &bytes_read, buf);
	if(err)
		goto err;
	printk("%s dat[0]:0x%x, dat[1]:0x%x,  dat[2]:0x%x, dat[3]:0x%xn",__func__,buf[0],buf[1],buf[2],buf[3]);
	//关闭
	put_mtd_device(mtd);
	return 0;
err:
	return -ENXIO;
	}

在uboot中读取,并传递给kernel

• 2.1 cmd/Makefile

  1	obj-y += get_lcd_value.o

• 2.2 cmd/get_lcd_value.c

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  #include <common.h> #include <command.h> #include <image.h> static int do_get_lcd_value(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { char buf[4]; int uImage_head_addr; uImage_head_addr = simple_strtoul(argv[1], NULL, 16); printf("agrv[1] addr 0x%xn",*(int *)uImage_head_addr); buf[0] = ((char *)uImage_head_addr)[3] & 0x0f; buf[1] = ((char *)uImage_head_addr)[2] & 0x0f; buf[0] |= (buf[1] << 4); buf[2] = ((char *)uImage_head_addr)[1] & 0x0f; buf[3] = ((char *)uImage_head_addr)[0] & 0x0f; buf[1] = (buf[3] << 4) | buf[2]; //将buf值设为环境变量loadlcdvalue setenv_hex("loadlcdvalue", *(int *)buf); } U_BOOT_CMD( get_lcd_value, CONFIG_SYS_MAXARGS, 0, do_get_lcd_value, "Get lcd value !n", "Usage: Get lcd valuen" );

• 2.3 include/configs/mx6dl_xxx_common.h

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  #define CONFIG_EXTRA_ENV_SETTINGS CONFIG_MFG_ENV_SETTINGS "loadsz=" KN_PART_SZ "