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SubjectRe: [PATCH v2 3/3] ARM: vf610: Add ARM Global Timer clocksource option
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



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