Re: cfi_cmdset_0002.c SST39VF3201B issue

Fabio Giovagnini
2011-10-06T12:48:35Z

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
>
>
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

--
Fabio Giovagnini

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