[LinuxBIOS] Use Linux MTD framework for SPI flash?

Jordan Crouse jordan.crouse at amd.com
Tue Jul 31 23:33:15 CEST 2007

On 31/07/07 23:19 +0200, Stefan Reinauer wrote:
> * Jordan Crouse <jordan.crouse at amd.com> [070731 17:28]:
> > I think that the MTD is the right horse to bet on here - if anything,
> > it will enrich a larger community.  And, if flashrom understands
> > how to talk to the MTD interfaces, and somebody adds a SPI chip to the
> > kernel that we don't yet know about, we win for free.
> In this scenario, who loads the correct kernel module(s)? 

The user.  

> Which southbridges does the MTD SPI code support? Last time I checked
> only some ARM embedded systems were possibly supported.

Sure - but what SPI southbridges does flashrom support?  The work has
to happen - its just a matter of where the work goes.  Personally, I would
rather put the work into the kernel, because as I said, that hits the
widest possible audience.

> > Even if we only put the really generic SPI code into the MTD subsystem,
> > I think its a good thing.  The way I see it, flashrom should _want_ to
> > use the generic interfaces, and if it can't, it will go its own way like
> > it does now.  Even in the worst cases, that will mean less work and less
> > duplication.
> Flashrom _is_ the generic interface for many systems. 
> I think mtd is overly generic and overly complex for what it helps for
> bios flash chips. But if we can easily support it (patches anyone) we
> should of course do it. For the task of bios flashing mtd only supports
> a fraction of systems flashrom supports, and it requires kernel updates
> for every new chip and system -- this was the reason I abandoned
> /dev/bios in favour of supporting flashrom.

Again - don't exclude MTD because it doesn't support devices today - if we
put as much work into the MTD drivers as we do into flashrom, then MTD
would be the well supported one, and flashrom would be struggling.

But this is just my opinion.  For my part, any new SPIish gadgets that
we happen to support will have a MTD driver, and I'll even patch flashrom
to support it (because I'm that nice of a guy).  If somebody is interested
in porting that support natively to flashrom, then good on ya.


Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.

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