Re: [PATCH v5 7/8] drivers: cpuidle: initialize Exynos driver through DT

Chander Kashyap
2014-07-18T08:45:01Z

Hi Lorenzo,

On 17 July 2014 19:50, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> wrote:
> On Wed, Jun 25, 2014 at 04:23:38PM +0100, Bartlomiej Zolnierkiewicz wrote:
>>
>> Hi,
>>
>> On Wednesday, June 25, 2014 03:10:20 PM Lorenzo Pieralisi wrote:
>> > With the introduction of DT based idle states, CPUidle drivers for
>> > ARM can now initialize idle states data through properties in the device
>> > tree.
>> >
>> > This patch adds code to the Exynos CPUidle driver to dynamically
>> > initialize idle states data through the updated device tree source
>> > files.
>> >
>> > Cc: Kukjin Kim <kgene.kim@samsung.com>
>> > Cc: Tomasz Figa <t.figa@samsung.com>
>> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>> > ---
>> > Compile tested, I am not sure I patched the right dts files, please check.
>>
>> cpuidle-exynos driver is currently working properly in deeper cpuidle
>> mode (AFTR) on Exynos4210 and Exynos5250 (please also see the following
>> patch from Tomasz Figa: [1]). There is ongoing work to AFTR mode work
>> also on Exynos4x12 and Exynos3250 but it is not complete yet. Exynos5410
>> OTOH should probably use the generic big little cpuidle driver (this SoC
>> is similar to Exynos5420 one for which Chander Kashyap has developed
>> cpuidle-big_little support [2]).
>>
>> Making long story short, I think that your patch should depend on patch
>> [1] and update only exynos4210.dtsi and exynos5250.dtsi. Also for your
>> patch #6 there needs to be some coordination with merging of Chander's
>> patchset ([2]).
>>
>> [1] http://www.spinics.net/lists/arm-kernel/msg341023.html
>> [2] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg664470.html
>
>
> exynos4210.dtsi does not even have cpu nodes in it. Should I add them or
> this might trigger regression (ie cpu_logical_map()) ?

Yes that can cause regression.

>
> I will post a new version soon, should I just patch 5250 for now ?
>
> I would need help to test this patch thanks.

I can test the patch for 5250.

>
> Lorenzo
>
>> > .../devicetree/bindings/arm/exynos/idle-states.txt | 27 ++++++++++++++++++++
>> > arch/arm/boot/dts/exynos3250.dtsi | 16 ++++++++++++
>> > arch/arm/boot/dts/exynos5250.dtsi | 15 +++++++++++
>> > arch/arm/boot/dts/exynos5410.dtsi | 17 +++++++++++++
>> > drivers/cpuidle/Kconfig.arm | 1 +
>> > drivers/cpuidle/cpuidle-exynos.c | 29 +++++++++++++---------
>> > 6 files changed, 93 insertions(+), 12 deletions(-)
>> > create mode 100644 Documentation/devicetree/bindings/arm/exynos/idle-states.txt
>>
>> Best regards,
>> --
>> Bartlomiej Zolnierkiewicz
>> Samsung R&D Institute Poland
>> Samsung Electronics
>>
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>>
>>
>

--
with warm regards,
Chander Kashyap