From: "Dale Farnsworth" <dale@farnsworth•org>
To: David Gibson <david@gibson•dropbear.id.au>
Cc: linuxppc-dev <Linuxppc-dev@ozlabs•org>,
Paul Mackerras <paulus@samba•org>
Subject: Re: [PATCH 10/13] powerpc: check cache coherency of kernel vs firmware
Date: Mon, 14 May 2007 07:44:21 -0700 [thread overview]
Message-ID: <20070514144420.GA8458@xyzzy.farnsworth.org> (raw)
In-Reply-To: <20070514004014.GF6517@localhost.localdomain>
On Mon, May 14, 2007 at 12:40:14AM +0000, David Gibson wrote:
> On Fri, May 11, 2007 at 05:57:35PM -0700, Mark A. Greer wrote:
> >
> > From: Dale Farnsworth <dale@farnsworth•org>
> >
> > check_cache_coherency() verifies that the cache coherency setting of
> > the kernel (CONFIG_NOT_COHERENT_CACHE) matches that left by the firmware,
> > as indicated by coherency-off device tree property.
>
> This looks really bogus. If the firmware reports a coherency state,
> then presumably there's some hardware switch to turn coherency on or
> off. In which case, can't the kernel just toggle that switch to
> whatever's appropriate for it?
Oh, if it were only a single hardware switch. This is currently done
as part of about 500 lines of window register setting code that would
need to be moved/copied into the kernel from the firmware/bootwrapper.
It looks like the coherency part involves changing the same field in
a dozen device window registers, plus a different field in a register
for each PCI bus. So that is doable, and preferable to just printing
an error and failing as the above referenced patch does.
I was very glad to see all of the window initialization code taken out
of the kernel and put into the bootwrapper, but I'm beginning to believe
that it needs to be put back in the kernel.
Mark, it's your code. What do you think?
-Dale
next prev parent reply other threads:[~2007-05-14 14:44 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-12 0:46 [PATCH 0/13] powerpc: Add support for Marvell/mv64x60 and prpmc2800 Mark A. Greer
2007-05-12 0:53 ` [PATCH 1/13] powerpc: Add Makefile rules to wrap dts file in zImage Mark A. Greer
2007-05-14 0:33 ` David Gibson
2007-05-14 3:46 ` Mark A. Greer
2007-05-14 3:49 ` David Gibson
2007-05-21 18:10 ` Mark A. Greer
2007-05-22 0:23 ` David Gibson
2007-05-24 21:28 ` Mark A. Greer
2007-05-25 1:32 ` David Gibson
2007-05-25 1:33 ` David Gibson
2007-05-25 20:50 ` Mark A. Greer
2007-05-28 4:43 ` David Gibson
2007-05-12 0:54 ` [PATCH 2/13] powerpc: Add bootwrapper support for Marvell/mv64x60 hostbridge Mark A. Greer
2007-05-12 0:54 ` [PATCH 3/13] powerpc: Add bootwrapper support for Marvell MPSC Mark A. Greer
2007-05-12 0:54 ` [PATCH 4/13] powerpc: Add bootwrapper support for Marvell/mv64x60 I2C Mark A. Greer
2007-05-12 0:55 ` [PATCH 5/13] powerpc: Add interrupt support for Marvell mv64x60 chips Mark A. Greer
2007-05-12 0:55 ` [PATCH 6/13] powerpc: Create Marvell mv64x60 MPSC (serial) platform_data Mark A. Greer
2007-05-12 0:56 ` [PATCH 7/13] powerpc: Create Marvell mv64x60 ethernet platform_data Mark A. Greer
2007-05-12 0:56 ` [PATCH 8/13] powerpc: Create Marvell mv64x60 I2C platform_data Mark A. Greer
2007-05-12 0:57 ` [PATCH 9/13] powerpc: Add Marvell mv64x60 PCI bridge support Mark A. Greer
2007-05-12 0:57 ` [PATCH 10/13] powerpc: check cache coherency of kernel vs firmware Mark A. Greer
2007-05-14 0:40 ` David Gibson
2007-05-14 12:34 ` Segher Boessenkool
2007-05-14 14:44 ` Dale Farnsworth [this message]
2007-05-14 20:27 ` Mark A. Greer
2007-05-12 0:57 ` [PATCH 11/13] powerpc: Add DTS file for the Motorola PrPMC2800 platform Mark A. Greer
2007-05-12 0:58 ` [PATCH 12/13] powerpc: Add bootwrapper support for " Mark A. Greer
2007-05-12 0:58 ` [PATCH 13/13] powerpc: Add arch/powerpc support for the Motorola PrPMC2800 Mark A. Greer
-- strict thread matches above, loose matches on Subject: below --
2007-05-10 20:02 [PATCH 0/13] powerpc: Add support for Marvell/mv64x60 and prpmc2800 Mark A. Greer
2007-05-10 20:08 ` [PATCH 10/13] powerpc: check cache coherency of kernel vs firmware Mark A. Greer
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