Subject: Re: [PATCH 03/24] arm: mm: add proc info for ScorpionMP
From: Catalin Marinas <catalin.marinas@arm.com>
To: Daniel Walker <dwalker@codeaurora.org>
Cc: Jeff Ohlstein <johlstei@codeaurora.org>,
        Russell King <linux@arm.linux.org.uk>, linux-arm-msm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Tony Lindgren <tony@atomide.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>
In-Reply-To: <1282922978.5075.13.camel@m0nster>
References: <1282922978.5075.13.camel@m0nster>
Content-Type: text/plain; charset="UTF-8"
Organization: ARM Limited
Date: Fri, 27 Aug 2010 17:04:32 +0100
Message-ID: <1282925072.26355.61.camel@e102109-lin.cambridge.arm.com>
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 2515
Lines: 59

On Fri, 2010-08-27 at 16:29 +0100, Daniel Walker wrote:
> On Fri, 2010-08-27 at 14:54 +0100, Catalin Marinas wrote:
> > On Wed, 2010-08-25 at 05:57 +0100, Jeff Ohlstein wrote:
> > > From: Daniel Walker <dwalker@codeaurora.org>
> > >
> > > ScorpionMP does not have the SMP/nAMP and TLB ops broadcasting bits in
> > > ACTLR.
> > >
> > > Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
> > > Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
> > > ---
> > >  arch/arm/mm/proc-v7.S |   24 ++++++++++++++++++++++++
> > >  1 files changed, 24 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> > > index 7aaf88a..98fd7e5 100644
> > > --- a/arch/arm/mm/proc-v7.S
> > > +++ b/arch/arm/mm/proc-v7.S
> > > @@ -196,6 +196,7 @@ __v7_setup:
> > >         orreq   r0, r0, #(1 << 6) | (1 << 0)    @ Enable SMP/nAMP mode and
> > >         mcreq   p15, 0, r0, c1, c0, 1           @ TLB ops broadcasting
> > >  #endif
> > > +__v7_msm_setup:
> > >         adr     r12, __v7_setup_stack           @ the local stack
> > >         stmia   r12, {r0-r5, r7, r9, r11, lr}
> > >         bl      v7_flush_dcache_all
> >
> > It may be better to move the generic __v7_setup here and have a specific
> > entry for ARM Ltd cores (mask 0xff0f0000 and value 0x410f0000).
> 
> I'm not sure I follow you.. Are you saying there are other cpu's that
> don't need the SMP stuff at the top of __v7_setup ?

The SMP/nAMP bit is something specific to the ARM11MPCore and Cortex-A9
processors produced by ARM. If you core doesn't need this, it should use
a default __v7_setup without any additional bits being set.

I'm not aware of other MP ARM processors produced by other companies
that would require exactly the same bit being set.

> > In general, I would have liked a different way (still ID-based) of
> > handling such issues without duplicating the whole structure. But I see
> > this becoming the standard as proc-v6.S follows it as well.
> 
> This whole thing was something Russell specifically asked for (and
> practically wrote for me).

Yes, I know and I'm not saying that you should change it in this patch.
It's just that I would have liked to only duplicate the setup function
rather than the whole procinfo structure.

-- 
Catalin

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/