16-bit JEDEC Flash

16-bit JEDEC Flash

[Erwin Authried]

>From the comments in jedec.c I figure out that 16-bit JEDEC flash is not supported.
There are still several manufacturers that produce flash without CFI (e.g., Atmel).
If that's true, wouldn't it be better to use the already existing cfi implementation to
emulate a CFI device, instead of implementing all that stuff again for non-CFI flash?
I believe it wouldn't be much more than having a table with the JEDEC id's as an index 
that contains all the CFI parameters.

-Erwin



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Re: 16-bit JEDEC Flash

[David Woodhouse]

eauth@softsys.co.at said:
> From the comments in jedec.c I figure out that 16-bit JEDEC flash is
> not supported. There are still several manufacturers that produce
> flash without CFI (e.g., Atmel). If that's true, wouldn't it be better
> to use the already existing cfi implementation to emulate a CFI
> device, instead of implementing all that stuff again for non-CFI
> flash? I believe it wouldn't be much more than having a table with the
> JEDEC id's as an index  that contains all the CFI parameters. 

Yes please, that seems like a sensible plan. :)

--
dwmw2




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RE: 16-bit JEDEC Flash

[Jonas Holmberg]

I tried something like that before writing amd_flash.c, but I noticed that many non-CFI flashes don't support some of the things that CFI-flashes support (e.g. unlock bypass). And I think the safest way to know if a non-CFI flash has finished erasing or writing would be to check the toggle or data polling bit instead of udelaying.

If your 16-bit flash uses the AMD command set you can just add it to the table in amd_flash_probe() and it should work right away.

There are of course many similarities between cfi_cmdset_0002.c and amd_flash.c (a lot of it is stolen from cfi_cmdset_0002.c), and we ought to make some of the CFI-specific stuff non-CFI-specific so that it can be used from amd_flash.c also.

/Jonas

> -----Original Message-----
> From: David Woodhouse [mailto:dwmw2@infradead.org]
> Sent: Wednesday, March 07, 2001 11:46 AM
> To: Erwin Authried
> Cc: 'mtd@infradead.org'
> Subject: Re: 16-bit JEDEC Flash 
> 
> 
> 
> eauth@softsys.co.at said:
> > From the comments in jedec.c I figure out that 16-bit JEDEC flash is
> > not supported. There are still several manufacturers that produce
> > flash without CFI (e.g., Atmel). If that's true, wouldn't 
> it be better
> > to use the already existing cfi implementation to emulate a CFI
> > device, instead of implementing all that stuff again for non-CFI
> > flash? I believe it wouldn't be much more than having a 
> table with the
> > JEDEC id's as an index  that contains all the CFI parameters. 
> 
> Yes please, that seems like a sensible plan. :)
> 
> --
> dwmw2
> 
> 
> 
> 
> To unsubscribe, send "unsubscribe mtd" to majordomo@infradead.org
> 


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