[PATCH v2 04/28] ARM: mm: cache-l2x0: Add support forre-enabling l2x0

Colin Cross ccross at android.com
Sat Feb 5 11:36:22 EST 2011


On Sat, Feb 5, 2011 at 4:41 AM, Santosh Shilimkar
<santosh.shilimkar at ti.com> wrote:
>> -----Original Message-----
>> From: Russell King - ARM Linux [mailto:linux at arm.linux.org.uk]
>> Sent: Saturday, February 05, 2011 3:18 PM
>> To: Santosh Shilimkar
>> Cc: Colin Cross; Will Deacon; Catalin Marinas; Linus Walleij;
>> konkers at android.com; Tony Lindgren; linux-kernel at vger.kernel.org;
>> linux-tegra at vger.kernel.org; olof at lixom.net; linux-arm-
>> kernel at lists.infradead.org
>> Subject: Re: [PATCH v2 04/28] ARM: mm: cache-l2x0: Add support
>> forre-enabling l2x0
>>
>> On Sat, Feb 05, 2011 at 01:21:24PM +0530, Santosh Shilimkar wrote:
>> > GIC save/restore on OMAP follows different strategy. There is a
>> > Predefined layout to save content and restore is done atomically
>> > by boot ROM code.
>> > L2 cache also same case. Only AUXCTRL needs to be programmed on
>> > wakeup from low power mode and that too with secure call. Rest
>> > of the registers are managed by boot ROM code.
>> >
>> > TWD is already managed through framework. Othe CPU low power
>> > sequence is very small and OMAP has restrictions on the last
>> > core to go down and first to wakeup.
>> >
>> > So at least I don't see any use of common notifiers for GIC
>> > and L2 will help OMAP lower power code.
>>
>> What this means is that we're going to end up littering things like
>> GIC
>> and other stuff with lots of individual SoC specific code to save
>> state
>> into individual SoC specific structures.  This is not sane, and
>> we're
>> not going to corrupt generic code with SoC specific code.
>
> Fully agree and hence flagged it early.
>
> Regards,
> Santosh
>

Would putting dummy values in the areas the boot ROM uses and then
letting the common GIC code restore over them cause any problems?



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