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Date: Thu, 23 Sep 2004 22:01:50 +0100
From: Ben Dooks <ben-mtd@fluff.org>
To: "Eric W. Biederman" <ebiederman@lnxi.com>
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Subject: Re: Fix to jedec_probe unlock addresses
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On Wed, Sep 22, 2004 at 07:48:40PM -0600, Eric W. Biederman wrote:
> Ben Dooks <ben-mtd@fluff.org> writes:
> 
> > Fix unlock address calculation for non-x8 chips for the
> > cfi cmdset code, which assumes always X8
> > 
> > Patch against 2.6.9-rc2 with 19th September CVS
> > 
> > Signed-off-by: Ben Dooks <ben-mtd@fluff.org>
> > 
> > --- linux-2.6.9-rc2-bk6-mtd20040919/drivers/mtd/chips/jedec_probe.c 2004-09-20
> > 13:02:46.000000000 +0100
> > 
> > +++ linux-2.6.9-rc2-bk6-mtd20040919-work/drivers/mtd/chips/jedec_probe.c
> > 2004-09-20 23:21:40.000000000 +0100
> > 
> > @@ -2046,7 +2046,15 @@
> >  	printk(KERN_INFO "%s: Found %d x%d devices at 0x%x in %d-bit bank\n",
> >  	       map->name, cfi_interleave(cfi), cfi->device_type*8, base, 
> >  	       map->bankwidth*8);
> > -	
> > +
> > +	/* fixup unlock addresses for the cmdset */
> > +
> > +	cfi->addr_unlock1 *= cfi_interleave(cfi) * cfi->device_type;
> > +	cfi->addr_unlock2 *= cfi_interleave(cfi) * cfi->device_type;
> > +
> > +	printk(KERN_DEBUG "unlocks at %08x,%08x\n", 
> > +	       cfi->addr_unlock1, cfi->addr_unlock2);
> > +
> >  	return 1;
> >  }
> 
> Hmm.  I think that points out a real issue but I think the bug actually
> lies in cfi_cmdset_0002.  
> 
> That fix makes below comment from cfi_cmdset_0002 clearly wrong.
> 	/*
> 	 * The CFI_DEVICETYPE_X8 argument is needed even when
> 	 * cfi->device_type != CFI_DEVICETYPE_X8.  The addresses for
> 	 * command sequences don't scale even when the device is
> 	 * wider.  This is the case for many of the cfi_send_gen_cmd()
> 	 * below.  I'm not sure, however, why some use
> 	 * cfi->device_type.
> 	 */

[snip]
 
> Does anyone have cfi cmdset 0002 devices in an interleaved configuration
> who would care to comment?

I took the jedec_probe alterations as I was unsure wether I was going
to damage anything else by changing the cfi cmdset 0002 code.

-- 
Ben (ben@fluff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'