flash_erase擦除NAND flash坏块失败

转自 http://blog.csdn.net/yuanlulu/article/details/7339895

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   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 <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\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;
 }