Re: cfi_cmdset_0002.c SST39VF3201B issue

angelo
2011-10-06T14:23:13Z

Hi,

i was working with main line kernel (2.6.36.2), and i have seen that the
issue has been fixed for example in 2.6.38,
to erase really a 4KB sector using flash cmd 0x50. This is probably why
jffs2 "seems" to work, with the patch in mkfs.jffs2.

But, as already pointed out, jffs2 could have problems, due to the fact
the minimal block size is 4KB + some bytes.

For who is interested, i patched the kernel 2.6.36.2 in my own way,
using 64KB physical erasesize and JFFS2 works great:

in cfi_cmdset_0002.c

static void fixup_old_sst_eraseregion(struct mtd_info *mtd)
{
struct map_info *map = mtd->priv;
struct cfi_private *cfi = map->fldrv_priv;

/*
* These flashes report two seperate eraseblock regions based on the
* sector_erase-size and block_erase-size, although they both
operate on the
* same memory. This is not allowed according to CFI, so we just
pick the
* sector_erase-size.
*/
+ cfi->cfiq->EraseRegionInfo[0] = cfi->cfiq->EraseRegionInfo[1];
+
cfi->cfiq->NumEraseRegions = 1;
}

Regards,
Angelo Dureghello

On 06/10/2011 14:48, Fabio Giovagnini wrote:
> I would try to keep the 4kBi blocks.
>
>
> regards
>
>
>
> Il giorno gio, 06/10/2011 alle 14.29 +0200, angelo ha scritto:
>
>> Dear all,
>>
>> like me some other users had issues with this chip and jffs2.
>>
>> From time to time users asks why they get errors trying to use jffs2
>> with this chip.
>>
>> This chip, from the datasheet, allows to erase 4KB "sectors" or 64KB
>> "blocks", replying to cfi queries with a "setcor" erase size and a
>> "block" erase size.
>>
>> I can be wrong of course, but this is what i figured out:
>>
>>
>> 1) fixup decision
>>
>> Someone of you decided to fix up this SST39VF3201 in this way:
>>
>> static void fixup_old_sst_eraseregion(struct mtd_info *mtd)
>> {
>> struct map_info *map = mtd->priv;
>> struct cfi_private *cfi = map->fldrv_priv;
>>
>> /*
>> * These flashes report two seperate eraseblock regions based on the
>> * sector_erase-size and block_erase-size, although they both
>> operate on the
>> * same memory. This is not allowed according to CFI, so we just
>> pick the
>> * sector_erase-size.
>> */
>> cfi->cfiq->NumEraseRegions = 1;
>> }
>>
>> Of course, in this way, deciding 0x1000 (sector-size) is the one to use,
>> jffs2 cannot be used safely, since
>> minimal data block is 4Kb + some hdr bytes. Wasn't better fixup to
>> "block" size (64K) ?
>>
>>
>> 2) after fixup decision, when jffs2 asks to erase a block to
>> cfi_cmdset_0002.c, cfi driver seems to erase wrongly a 64K block.
>> This is what happen in detail:
>> jffs erase.c, to erase a block does: mtd->erase(), with a len
>> mtd->erasesize (4KB).
>> mtd->erase() is calls cfi_amdstd_erase_varsize ...
>> finally, do_erase_oneblock is called, where:
>>
>> cfi_send_gen_cmd(0xAA, cfi->addr_unlock1, chip->start, map, cfi,
>> cfi->device_type, NULL);
>> cfi_send_gen_cmd(0x55, cfi->addr_unlock2, chip->start, map, cfi,
>> cfi->device_type, NULL);
>> cfi_send_gen_cmd(0x80, cfi->addr_unlock1, chip->start, map, cfi,
>> cfi->device_type, NULL);
>> cfi_send_gen_cmd(0xAA, cfi->addr_unlock1, chip->start, map, cfi,
>> cfi->device_type, NULL);
>> cfi_send_gen_cmd(0x55, cfi->addr_unlock2, chip->start, map, cfi,
>> cfi->device_type, NULL);
>> map_write(map, CMD(0x30), adr);
>>
>> but this chip uses 0x30 cmd to erase a 64 KB block, and 0x50 to erase a
>> sector.
>>
>> Please let me know if i am in the right direction, so i can think about
>> a patch that allows
>> jffs2 to be used with native hw 64KB block erasesize.
>>
>> Regards
>> Angelo Dureghello
>>
>>
>>
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>>
>