Re: cfi_cmdset_0002.c SST39VF3201B issue

[Fabio Giovagnini <fabio.giovagnini@aurion-tech.com>]

Hi Angelo,
I have worked with 2.6.38 and I have used 0x50 command and modification
into mkfs.jffs2 utility in order to accomplish a 4k fs sector size.
It is working and I think that in a not so huge memory support a 4k
sector allows a better management rather than 64k sector.

Regards


Il giorno gio, 06/10/2011 alle 15.44 +0200, angelo ha scritto:
> Hi Giovanni,
> 
> i can be wrong, but i think this is a bug of the cfi command set, and
> should be fixed in the best way from the maintainer.
> This because mtd->regions[x].erasesize is set to 4KiB but everytime an
> mtd->erase is requested, a block of 64KB is erased.
> 
> Unfortunately, creating "virtual" 32 or 64KB" erasesizes to allows
> jffs2 to work is not convenient and also quite long job.
> 
> I will try the simplest patch for now (using native 64Kblocks as many
> other nor flash) and will post back shortly if the fix work, almost
> for jffs2.
> 
> Regards,
> angelo
> 
> 
> 
> 
> 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
> > > 
> > > 
> > > 
> > > ______________________________________________________
> > > Linux MTD discussion mailing list
> > > http://lists.infradead.org/mailman/listinfo/linux-mtd/
> > >     
> 
> 
> -- 
>  .:.:.SYSAM.:.:.
> 
>   di Angelo Dureghello
>     via San Nazario 149
>       34151, Trieste, Italy
>     ++39 340 7631990
>   www.sysam.it
> 
> 

-- 
Fabio Giovagnini

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