flash_erase擦除NAND flash坏块失败

板子使用busybox文件系统，带了mtd-utils的工具，包括flash_erase。首先查看帮助信息：

[root@M3250 ~]# flash_erase --h Usage: flash_erase [options] MTD_DEVICE <start offset> <block count> Erase blocks of the specified MTD device. Specify a count of 0 to erase to end of device. -j, --jffs2 format the device for jffs2 -N, --noskipbad dont skip bad blocks -u, --unlock unlock sectors before erasing -q, --quiet display progress messages --silent same as --quiet --help display this help and exit --version output version information and exit [root@M3250 ~]#

看样子flash_erase默认不擦除坏块的，但可以使用-N选项启用这个功能。但是结果如下：

[root@M3250 ~]# flash_erase -N /dev/mtd4 0 0 Erasing 128 Kibyte @ 0 -- 0 % nand_erase_nand: attempt to erase a bad block at page 0x0001ff00 Erasing 128 Kibyte @ 2nand_erase_nand: attempt to erase a bad block at page0x0001ff40 Erasing 128 Kibyte @ 40000 -- 50 % complete libmtd: error!: MEMERASE64 ioctl failed for eraseblock 2 (mtd4) error 5 (Input/output error) flash_erase: error!: /dev/mtd4: MTD Erase failure error 5 (Input/output error) Erasing 128 Kibyte @ 60000 -- 75 % complete libmtd: error!: MEMERASE64 ioctl failed for eraseblock 3 (mtd4) error 5 (Input/output error) flash_erase: error!: /dev/mtd4: MTD Erase failure error 5 (Input/output error) Erasing 128 Kibyte @ 60000 -- 100 % complete

还是擦不了。看了下内核的代码，在/drivers/mtd/nand/nand_base.c中nand_erase_nand函数有这么一段：

while (len) { /* * heck if we have a bad block, we do not erase bad blocks ! */ if (nand_block_checkbad(mtd, ((loff_t) page) << chip->page_shift, 0, allowbbt)) { printk(KERN_WARNING "%s:attempt to erase a bad block " "at page 0x%08x ", __func__, page); instr->state = MTD_ERASE_FAILED; goto erase_exit; }

结论就是linux内核不支持擦除坏块。 解决办法：在uboot中使用"nand scrub"擦除。

附上自己写的mtd擦除程序：

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <mtd/mtd-user.h>
#include <sys/ioctl.h>

int main(int argc, char *argv[])
{
        int dev_fd;
        int result;
        erase_info_t erase;
        mtd_info_t mtd;
        int rt = 0;

        if (argc !=2) {
                printf("%s:input a argument like /dev/mtdX
", argv[0]);
                rt = -1;
                goto exit;
        }
        printf("the device you want to erase is %s
", argv[1]);

        dev_fd = open (argv[1], O_SYNC | O_RDWR);
        if (dev_fd < 0) {
                printf("open %s failed
", argv[1]);
                perror("erase mtd");
                rt =  -1;
                goto exit;
        }

        if (ioctl(dev_fd, MEMGETINFO, &mtd) < 0) {
                printf("%s:MTD getinfo failed
", argv[1]);
                perror("get mtd info");
                rt = -1;
                goto close;
        }

        erase.start = 0;
        erase.length = mtd.size;          
                                            
        if (ioctl (dev_fd, MEMERASE, &erase) < 0) {
                printf("%s: erase failed
", argv[1]);
                perror("erase mtd");
                rt = -1;
                goto close;
        }
        printf("erase %s sucess
", argv[1]);

close:
        close(dev_fd);
exit:
        return rt;
}

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