From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Warren <swarren@wwwdotorg.org>
Subject: Re: [PATCH 00/16] Another 16 L2C patches
Date: Mon, 28 Apr 2014 12:08:11 -0600
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To: Russell King - ARM Linux <linux@arm.linux.org.uk>, Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: linux-tegra@vger.kernel.org, Thierry Reding <thierry.reding@gmail.com>, linux-arm-kernel@lists.infradead.org
List-Id: linux-tegra@vger.kernel.org

(Dropping most people from CC since this sub-thread is a Tegra-specific
discussion)

On 04/28/2014 11:39 AM, Russell King - ARM Linux wrote:
> On Mon, Apr 28, 2014 at 11:27:09AM -0600, Stephen Warren wrote:
...
>> I do see one error in dmesg during boot, but it doesn't appear to
>> negatively affect operation in brief testing, and is present in
>> linux-next without this series anyway. Is this message a problem?
>>
>>> [    0.000000] L2C: platform modifies aux control register: 0x02080000 -> 0x3e480001
>>> [    0.000000] L2C: DT/platform modifies aux control register: 0x02080000 -> 0x3e480001
>>> [    0.000000] L2C-310 errata 727915 769419 enabled
>>> [    0.000000] L2C-310 enabling early BRESP for Cortex-A9
>>> [    0.000000] L2C-310: enabling full line of zeros but not enabled in Cortex-A9
>>                           ^^^^^^ this is logged at error level
> 
> Correct, it's an error because on Tegra you explicitly set bit 0 in the
> auxiliary control register, which is pointless unless the feature is
> also enabled in the Cortex-A9 control register as well.

Please forgive my almost complete lack of knowledge re: cache
controllers. Is the correct fix for this:

a) To remove bit 0 from the aux_val passed to l2x0_of_init()

b) To set some BIT(3) in the Cortex-A9 auxcr, so this feature is enabled
there too.

And if (b), I assume that's something that the bootloader should be
doing, not the kernel?

Thanks.