Re: [Yaffs1] mkyaffs exits with "MTD Erase failure"

[Martin Egholm Nielsen <martin@egholm-nielsen.dk>]

Hi,

Ricard Wanderlof wrote:
> On Mon, 4 Jun 2007, Martin Egholm Nielsen wrote:
>>>>So, I fixed the timing in the kernel and tried erasing the flash
>>>>again. But with no luck - mkyaffs refuses to erase/program the
>>>>flash:

>>>Mtd refuses to erase blocks that have been marked bad. There is no
>>>workaround on a running kernel, but it is possible to patch the
>>>kernel to do this.

>>But as you see, flash_eraseall on the same device works perfectly fine:
>>flash_eraseall /dev/mtd0
>>....
>>Skipping bad block at 0x0179c000
>>Erasing 16 Kibyte @ 1ffc000 -- 99 % complete.

> flash_eraseall skips bad blocks while erasing. I don't know how mkyaffs 
> works though.

Well, glancing at the code, it should be doing something like it:

==== ORIGINAL mkyaffs.c ====
for(addr = 0; addr < meminfo.size; addr += meminfo.erasesize)
{
   /* Read the OOB data to determine if the block is valid.
    * If the block is damaged, then byte 5 of the OOB data will
    * have at least 2 zero bits.
    */
   oob.start = addr;
   oob.length = 16;
   oob.ptr = oobbuf;
   if (ioctl(fd, MEMREADOOB, &oob) != 0)
   {
     perror("ioctl(MEMREADOOB)");
     close(fd);
     exit(1);
   }

   if(countBits[oobbuf[5]] < 7)
   {
     printf("Block at 0x08%lx is damaged and is not being 
formatted\n",addr);
   }
=======================

However, it doesn't seem to do the trick. So I copied the check from 
"flash_eraseall" and put in, as well:

==== NEW mkyaffs.c ====
for(addr = 0; addr < meminfo.size; addr += meminfo.erasesize)
{
   /* MEN 2007-06-06 */
   loff_t bah = addr;
   int ret = ioctl(fd, MEMGETBADBLOCK, &bah);
   if (ret > 0)
   {
     printf( "Block at 0x08%lx would have been ignored by 
flash_eraseall!\n", addr );
     continue;
   } // if

   // OLD CODE HERE
=======================


And now it seems to work:

# mkyaffs-hacked-2007-06-06 -e /dev/mtd0
argc 3 sh 0 optcnt 2
Erasing and programming NAND
Erasing block at 0x080
Erasing block at 0x084000
...
Erasing block at 0x0898000
Block at 0x089c000 would have been ignored by flash_eraseall!
....


So that's good!? Unless there is a reason why that check was not there 
originally!
Charles Manning, do you care for a comment?


> You can always re-mark the factory bad ones, given that you have written 
> down which they were once... if you are using a flash-based BBT, erasing 
> the BBT blocks would suffice, as the bad block management in jffs2 when 
> using a flash-based BBT doesn't touch bad block markers. I would assume 
> from your reasoning that you are not using a flash-based BBT?

I don't, no. And I didn't write down the factory ones...


BR,
  Martin