Re: [PATCH v4 3/6] ARM: Add Krait L2 accessor functions
From: Stephen Boyd
Date: Tue Jan 07 2014 - 18:10:16 EST
On 01/07/14 15:07, Borislav Petkov wrote:
> On Mon, Dec 30, 2013 at 12:14:14PM -0800, Stephen Boyd wrote:
>> Krait CPUs have a handful of L2 cache controller registers that
>> live behind a cp15 based indirection register. First you program
>> the indirection register (l2cpselr) to point the L2 'window'
>> register (l2cpdr) at what you want to read/write. Then you
>> read/write the 'window' register to do what you want. The
>> l2cpselr register is not banked per-cpu so we must lock around
>> accesses to it to prevent other CPUs from re-pointing l2cpdr
>> underneath us.
>> Cc: Mark Rutland <mark.rutland@xxxxxxx>
>> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
>> arch/arm/common/Kconfig | 3 ++
>> arch/arm/common/Makefile | 1 +
>> arch/arm/common/krait-l2-accessors.c | 58 +++++++++++++++++++++++++++++++
>> arch/arm/include/asm/krait-l2-accessors.h | 20 +++++++++++
> I'm no ARM guy but out of curiosity, why is this code not part of the
> krait edac driver? IOW, is there a compelling reason for it to be in
This is used for more than just the edac driver. In the future, we'll
need this for the cpufreq driver and the l2 performance monitor driver.
I suppose I could have stated that in the commit text.
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