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Message-ID: <20130524164055.GA18614@n2100.arm.linux.org.uk>
Date: Fri, 24 May 2013 17:40:56 +0100
From: Russell King - ARM Linux <linux@....linux.org.uk>
To: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@...osoft.com>
Cc: "Yang, Wenyou" <Wenyou.Yang@...el.com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"Ferre, Nicolas" <Nicolas.FERRE@...el.com>,
"linux@...im.org.za" <linux@...im.org.za>
Subject: Re: [PATCH] ARM: at91: Fix: Change internal SRAM memory type to
"MT_MEMORY_SO"
On Fri, May 24, 2013 at 04:03:22PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 12:20 Fri 24 May , Russell King - ARM Linux wrote:
> > On Fri, May 24, 2013 at 07:11:04AM +0000, Yang, Wenyou wrote:
> > > The story is: for sama5d3x with Cortex-A5 core, if not so, when copying
> > > code snippet to the internal SRAM, then jump to run this code, but fail
> > > to run.
> >
> > And that is where your mistake is - you forgot that you're working with
> > a CPU with harvard caches which will require some cache maintanence
> > between copying the code and executing it.
> >
> > You want to look at flush_icache_range() rather than making this memory
> > strongly ordered.
>
> I understand your point but today we map a SRAM as MT_DEVICE
If you map SRAM as MT_DEVICE then you won't be able to execute code from
it. It needs to be a normal memory mapping.
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