Re: Flash drivers and filesystem (fwd)

Re: Flash drivers and filesystem (fwd)

[Alexander Larsson]

I don't have time to look at this. Anyone interested?

Attachment at
ftp://ftp.signum.se/pub/alex/amd_changes.patch

(listserver ate the first try.)

/ Alex

---------- Forwarded message ----------
Date: Wed, 30 Jun 1999 13:31:41 +0000
From: kd@flaga.is
To: Alexander Larsson <alex@signum.se>
Subject: Re: Flash drivers and filesystem

Hello,

Thanks for the utils you sent me. I am now able to create ext2fs on a part
of the flash chip. Now I only need to get Linux
to reqognice the flash partition in the boot so that Linux can boot from
it...

Anyway, as I mentioned before I have changed some things to make the driver
compatible with the am29lv160B* flash chip.
I was going to clean up my changes before I sent them to you. But now I am
starting my summervaction and I don't have time
to do that until this autumn. I send you the patch and you decide what to
do with it it might be helpful for others.

There are also some changes that might be helpful for your chip (8x
bitwith) , especially in the detection code.

My proposition is for the time beeing is to make amd_flash8x.c (your
amd_flash.c) and amd_flash16x.c (amd_flash.c with my patch) and make just
one of them compiled in at any one time.

Anyway I will probably not touch this thing until august.

Regards,

K.D.

(See attached file: flash.diff)



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Re: Flash drivers and filesystem (fwd)

[Jason Gunthorpe]

On Tue, 6 Jul 1999, Alexander Larsson wrote:

> I don't have time to look at this. Anyone interested?
> 
> Attachment at
> ftp://ftp.signum.se/pub/alex/amd_changes.patch

What is this applied against? This looks remarkably like it would fit
nicely with the more general chagnes I made... 

Everyone rewriting the flash chip code for every new device is getting
old :>

Jason



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Re: Flash drivers and filesystem (fwd)

[David Woodhouse]

jgg@deltatee.com said:
>  What is this applied against? This looks remarkably like it would fit
> nicely with the more general chagnes I made... 

Against Alex's original patch, I believe.

> Everyone rewriting the flash chip code for every new device is getting
> old :> 

Indeed. I'm working on recombining them all into one - was yours based upon
mine, or were they both based on something I can't find any more (I honestly
can't remember)?

Once we've done that, I'll look at putting up a public CVS server.




----                                 ----                                 ----
David Woodhouse        David.Woodhouse@mvhi.com       Office: (+44) 1223 810302
 Project Leader,     Process Information Systems      Mobile: (+44) 976 658355
    Axiom (Cambridge) Ltd., Swaffham Bulbeck, Cambridge, CB5 0NA, UK.
             finger dwmw2@ferret.lmh.ox.ac.uk for PGP key.




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Re: Flash drivers and filesystem (fwd)

[Jason Gunthorpe]

On Tue, 6 Jul 1999, David Woodhouse wrote:

> jgg@deltatee.com said:
> >  What is this applied against? This looks remarkably like it would fit
> > nicely with the more general chagnes I made... 
> 
> Against Alex's original patch, I believe.

Hm, I don't have that code, just the original MTD stuff that was posted on
lwn some weeks back.
 
> > Everyone rewriting the flash chip code for every new device is getting
> > old :> 
> 
> Indeed. I'm working on recombining them all into one - was yours based upon
> mine, or were they both based on something I can't find any more (I honestly
> can't remember)?

Well, mine is the most different of all of them and has a bit of a strange
history. I started with the MTD (which was originally derived from the
PCMICA code) stuff I mentioned above and wrote a complete working driver
for that then I talked to my friend Gergely who had written a from scratch
block driver for his flash board, I also needed a block driver so I took
his stuff and my stuff and re-arranged the two, then I wrote another
driver for another board here and we end up with my version. The entire
thing is from scratch and ended up pretty clean, I c+p'd ideas from
everywhere to get it going though.

Jason



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Re: Flash drivers and filesystem (fwd)

[Gergely Madarasz]

On Tue, 6 Jul 1999, Jason Gunthorpe wrote:

> 
> On Tue, 6 Jul 1999, David Woodhouse wrote:
> 
> > jgg@deltatee.com said:
> > >  What is this applied against? This looks remarkably like it would fit
> > > nicely with the more general chagnes I made... 
> > 
> > Against Alex's original patch, I believe.
> 
> Hm, I don't have that code, just the original MTD stuff that was posted on
> lwn some weeks back.
>  
> > > Everyone rewriting the flash chip code for every new device is getting
> > > old :> 
> > 
> > Indeed. I'm working on recombining them all into one - was yours based upon
> > mine, or were they both based on something I can't find any more (I honestly
> > can't remember)?
> 
> Well, mine is the most different of all of them and has a bit of a strange
> history. I started with the MTD (which was originally derived from the
> PCMICA code) stuff I mentioned above and wrote a complete working driver
> for that then I talked to my friend Gergely who had written a from scratch
> block driver for his flash board, I also needed a block driver so I took

Actually my driver was a transparent block device with some hacks to make 
big writes in 64k blocks, did erase on the fly, so there was no need to
specifically erase it, so any rw filesystem could be put on it.. of course
it would wear out quickly...
I managed to boot linux from it using a small bios extensions which
emulated a floppy, and a few hacks to the ll_rw_blk and ramdisk code to
allow the kernel to load a ramdisk from this special device.
This was the fastest way I could produce something interesting to show to
the people because we had attended a conference/expo a couple of weeks
after this flash board has been finished... linux started booting from
it two days before the expo :) 
It booted, ran nicely, I could save the configuration, etc.

Anyway, Jasons code seems very nice, this board (a sync serial board btw
with a flash piggyback attached) works with it ok (except when it
hangs when I want to write a byte which hasn't been erased :)) and there
are still some small scheduling issues... 

Greg



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