[RFC] [PATCH] ARM: save/restore power control register on Cortex-A9 suspend/resume

[Chander Kashyap]

On 2 July 2014 08:57, Nicolas Pitre <nicolas.pitre at linaro.org> wrote:
> On Wed, 2 Jul 2014, Chander Kashyap wrote:
>
>> On Tue, Jul 1, 2014 at 6:18 PM, Russell King - ARM Linux
>> <linux at arm.linux.org.uk> wrote:
>> > On Tue, Jul 01, 2014 at 06:15:49PM +0530, Chander Kashyap wrote:
>> >> The CP15 power register holds clock latency and dynamic clock gating settings
>> >> for Cortex-A9 processor, which lost during the suspend/resume. So it needs to
>> >> be saved/restored on suspend/resume.
>> >>
>> >> Signed-off-by: Chander Kashyap <k.chander at samsung.com>
>> >> ---
>> >>  It is depedent on: ARM: save/restore diagnostic register on Cortex-A9 suspend/resume
>> >>  http://www.spinics.net/lists/arm-kernel/msg340506.html
>> >>
>> >>  arch/arm/mm/proc-v7.S |    6 +++++-
>> >>  1 file changed, 5 insertions(+), 1 deletion(-)
>> >>
>> >> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
>> >> index e26bfaa..9905df5 100644
>> >> --- a/arch/arm/mm/proc-v7.S
>> >> +++ b/arch/arm/mm/proc-v7.S
>> >> @@ -163,12 +163,14 @@ ENDPROC(cpu_v7_do_resume)
>> >>       globl_equ       cpu_ca9mp_switch_mm,    cpu_v7_switch_mm
>> >>       globl_equ       cpu_ca9mp_set_pte_ext,  cpu_v7_set_pte_ext
>> >>  .globl       cpu_ca9mp_suspend_size
>> >> -.equ cpu_ca9mp_suspend_size, cpu_v7_suspend_size + 1 * 4
>> >> +.equ cpu_ca9mp_suspend_size, cpu_v7_suspend_size + 2 * 4
>> >>  #ifdef CONFIG_ARM_CPU_SUSPEND
>> >>  ENTRY(cpu_ca9mp_do_suspend)
>> >>       stmfd   sp!, {r4}
>> >>       mrc     p15, 0, r4, c15, c0, 1  @ Diagnostic register
>> >>       stmia   r0!, {r4}
>> >> +     mrc     p15, 0, r4, c15, c0, 0  @ Power register
>> >> +     stmia   r0!, {r4}
>> >>       ldmfd   sp!, {r4}
>> >
>> > Please combine these - yes, it'll be a larger change, but it'll be much
>> > better.
>>
>> Are asking me to squash this patch with Shawn's patch?
>> If so i will do that.
>
> I'm not sure that's what RMK ment.
>
> You should at least merge the loads and stores into a combined ldmia and
> stmia instructions as illustrated.

Sure I will do that.

>
>>
>> >
>> >         stmfd   sp!, {r4-r5}
>> >         mrc     p15, 0, r4, c15, c0, 1  @ Diagnostic register
>> >         mrc     p15, 0, r5, c15, c0, 0  @ Power register
>> >         stmia   r0!, {r4-r5}
>> >         ldmfd   sp!, {r4-r5}
>> >
>> >
>> >>       b       cpu_v7_do_suspend
>> >>  ENDPROC(cpu_ca9mp_do_suspend)
>> >> @@ -176,6 +178,8 @@ ENDPROC(cpu_ca9mp_do_suspend)
>> >>  ENTRY(cpu_ca9mp_do_resume)
>> >>       ldmia   r0!, {r4}
>> >>       mcr     p15, 0, r4, c15, c0, 1  @ Diagnostic register
>> >> +     ldmia   r0!, {r4}
>> >> +     mcr     p15, 0, r4, c15, c0, 0  @ Power register
>> >
>> >         ldmia   r0!, {r4-r5}
>> >         mcr     p15, 0, r4, c15, c0, 1  @ Diagnostic register
>> >         mcr     p15, 0, r5, c15, c0, 0  @ Power register
>>
>> I will do these changes
>>
>>
>> Thanks for the review.
>>
>> >
>> >>       b       cpu_v7_do_resume
>> >>  ENDPROC(cpu_ca9mp_do_resume)
>> >>  #endif
>> >
>> > Thanks.
>> >
>> > --
>> > FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly
>> > improving, and getting towards what was expected from it.
>> >
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>>
>
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Thanks Nicolas

-- 
with warm regards,
Chander Kashyap