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SubjectRe: [PATCH v2 3/3] ARM: vf610: Add ARM Global Timer clocksource option
Am 2014-09-29 13:51, schrieb Shawn Guo:
> On Wed, Sep 24, 2014 at 06:20:10PM +0200, Stefan Agner wrote:
>> Add the ARM Global Timer as clocksource/scheduler clock option and
>> use it as default scheduler clock. This leaves the PIT timer for
>> other users e.g. the secondary Cortex-M4 core. Also, the Global Timer
>> has double the precission (running at pheripheral clock compared to
>> IPG clock) and a 64-bit incrementing counter register. We still keep
>> the PIT timer as an secondary option in case the ARM Global Timer is
>> not available.
>>
>> Signed-off-by: Stefan Agner <stefan@agner.ch>
>> ---
>> arch/arm/mach-imx/Kconfig | 19 ++++++++++++++++++-
>> 1 file changed, 18 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
>> index 11b2957..9482f58 100644
>> --- a/arch/arm/mach-imx/Kconfig
>> +++ b/arch/arm/mach-imx/Kconfig
>> @@ -633,12 +633,29 @@ config SOC_VF610
>> bool "Vybrid Family VF610 support"
>> select ARM_GIC
>> select PINCTRL_VF610
>> - select VF_PIT_TIMER
>> select PL310_ERRATA_769419 if CACHE_L2X0
>>
>> help
>> This enable support for Freescale Vybrid VF610 processor.
>>
>> +choice
>> + prompt "Clocksource for scheduler clock"
>> + depends on SOC_VF610
>> + default ARM_GLOBAL_TIMER
>> +
>> + config ARM_GLOBAL_TIMER
>> + bool "Use ARM Global Timer"
>> + select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
>> + help
>> + Use the ARM Global Timer as clocksource
>> +
>> + config VF_PIT_TIMER
>> + bool "Use PIT timer"
>> + help
>> + Use SoC Periodic Interrupt Timer (PIT) as clocksource
>> +
>> +endchoice
>> +
>
> As per the report from 0-DAY kernel build test (thanks), the change
> causes the following warning on a particular config.
>
> warning: (ARCH_ROCKCHIP && ARCH_BCM_5301X) selects
> CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK which has unmet direct
> dependencies (ARM_GLOBAL_TIMER)
>
> It looks the redefinition of ARM_GLOBAL_TIMER is the cause for that
> warning. I think it's more safer to use new config symbols for choosing
> the clocksource device for VF610. I propose the following change to fix
> the warning. If there is no objection, I will squash it into the
> original commit soon.
>
> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
> index 9482f5837b7e..e26b0fdd72db 100644
> --- a/arch/arm/mach-imx/Kconfig
> +++ b/arch/arm/mach-imx/Kconfig
> @@ -641,16 +641,18 @@ config SOC_VF610
> choice
> prompt "Clocksource for scheduler clock"
> depends on SOC_VF610
> - default ARM_GLOBAL_TIMER
> + default VF_USE_ARM_GLOBAL_TIMER
>
> - config ARM_GLOBAL_TIMER
> + config VF_USE_ARM_GLOBAL_TIMER
> bool "Use ARM Global Timer"
> + select ARM_GLOBAL_TIMER
> select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
> help
> Use the ARM Global Timer as clocksource
>
> - config VF_PIT_TIMER
> + config VF_USE_PIT_TIMER
> bool "Use PIT timer"
> + select VF_PIT_TIMER
> help
> Use SoC Periodic Interrupt Timer (PIT) as clocksource

I thought that Kconfig actually allowed to define a config symbol twice.
But maybe this is not a good idea with dependencies (depends on
SOC_VF610 on the choice level...?).

Thx Shawn, sorry about that.

Acked-by: Stefan Agner <stefan@agner.ch>


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