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
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   don't 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\n", __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 
#include 
#include 
#include 
#include 

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\n", argv[0]);
                rt = -1;
                goto exit;
        }
        printf("the device you want to erase is %s\n", argv[1]);

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

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

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

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作者：yuanlulu
http://blog.csdn.net/yuanlulu
版权没有，但是转载请保留此段声明

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