Thomas Gleixner wrote:
> Hmm, can you verify that the chip is erased correctly, when you do an
> flash_eraseall ? Dump it and check for nonzero pages. 

I used:
# flash_eraseall /dev/mtd/4
# nanddump /dev/mtd/4 dump.out

No, not all spages are erased after doing a flash_eraseall. i.e. they were not 
all 0xff.

The very first 8MB Flash partition that I started using for development is 
missing about 60% of its space due to "bad eraseblocks". The second 8MB Flash 
partition is missing only 1%. Luckily I make my own Smartmedia cards, so I can 
simply solder in a new Flash chip for further development. From now on I think 
I will make my partitions much smaller so I don't "lose" as many. ;)

y2 # df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/root            102901816  77308708  20365960  79% /
tmpfs                    15428       152     15276   1% /var
/dev/mtdblock/4          16368      9904      6464  61% /mnt/y1
/dev/mtdblock/5          16368       176     16192   1% /mnt/y2
y2 # ll /mnt/y1
yaffs_readdir: starting at 0
yaffs_readdir: starting at 3
drw-rw-rw-    1 root     root          512 Dec  6 11:12 ./
drwxrwxr-x    9 root     100          4096 Nov 11 10:17 ../
drw-rw-rw-    1 root     root          512 Dec  6 11:12 lost+found/
y2 # ll /mnt/y2
yaffs_readdir: starting at 0
yaffs_readdir: starting at 3
drw-rw-rw-    1 root     root          512 Dec  6 11:12 ./
drwxrwxr-x    9 root     100          4096 Nov 11 10:17 ../
drw-rw-rw-    1 root     root          512 Dec  6 11:12 lost+found/


 >>Surely it's not the easy to "break" a NAND chip? Can my original NAND be 
recovered?
 >>
 > It's quite easy, if the timing is wrong or if the rdy/busy check is not
 > reliable.

Is there a utility that writes to every single page, reads back the data and 
then marks the pages correctly? Or are those "bad eraseblocks" permanently lost?


 > Can I have a look at your board driver ?

Sure, see attached.

I simply modified the existing at91_nand.c file to compile with the latest MTD 
drivers. see 
http://lists.infradead.org/pipermail/linux-mtd/2004-December/011039.html for 
details on the changes I made to at91_nand.c


regards,


Aras Vaichas