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List:       uclinux-dev
Subject:    RE: [uClinux-dev] PATCH: speedup of flash writing (cfi_cmdset_0002.c)
From:       Erwin Authried <eauth () softsys ! co ! at>
Date:       2006-04-27 8:37:39
Message-ID: 1146127059.20959.92.camel () justakiss
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Am Donnerstag, den 27.04.2006, 09:45 +0200 schrieb Falk Brettschneider:
> Hi,
> 
> > --- Ursprüngliche Nachricht ---
> > Von: "Barry Baldwin" <bbaldwin@indyme.com>
> >
> > Just out of curiosity, what flash chip are you using?  Our
> > flash write times are painfully slow and we might want to design in a
> > different flash chip if we can speed up our write times.
> I have an AMD flash of 16MB (Am29LV128) which is accepted by the CFI
> auto-detection. Look at
> http://www.amd.com.cn/CHCN/assets/content_type/white_papers_and_tech_docs/25270c5.pdf
> in table 11 for the "Write to Buffer" command.
> I think all bigger flash chips have that CFI command AA 55 25 count.
Maybe, but there are a lot of smaller chips that do not support this.
There's a parameter in the CFI device geometry definition (word 2bh)
that specifies the nr. of bytes in multi-byte writes. If it is 0,
multi-byte writes are unsupported.

> Having file access via JFFS2 system (including compression of the data with
> zlib) the write time of my firmware file (350kB) is about 6secs with my
> patch, I just use fopen, fwrite, fflush, fclose for that. In case of direct
> writing&verifying (means not using JFFS2) I can write a 900kB Linux kernel
> in 7 seconds.
> 
> BTW: I don't have a clue who maintains the flash drivers for uclinux and how
> there is a chance to get my patch in the public CVS. Can anybody help,
> please?
have you checked the latest MTD code if that isn't supported already?

Regards,
Erwin


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