diff mbox series

[v2] clocksource: exynos_mct: Increase priority over ARM arch timer

Message ID 20190321082608.21366-1-m.szyprowski@samsung.com (mailing list archive)
State Mainlined
Commit 6282edb72bed5324352522d732080d4c1b9dfed6
Headers show
Series [v2] clocksource: exynos_mct: Increase priority over ARM arch timer | expand

Commit Message

Marek Szyprowski March 21, 2019, 8:26 a.m. UTC 
Exynos Multi-Core Timer driver (exynos_mct) must be started before ARM
Architected Timers (arch_timer), because they both share some common
hardware blocks (global system counter) and turning on MCT is needed
to get ARM Architected Timer working properly. Increase MCT timer rating
and hotplug priority over ARM Archictected timer driver to achieve that.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
---
v2: added comments about the relation to ARM arch timer
    rebased onto v5.1-rc1
v1: https://patchwork.kernel.org/patch/10814921/
---
 drivers/clocksource/exynos_mct.c | 4 ++--
 include/linux/cpuhotplug.h       | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

Comments

Chanwoo Choi March 21, 2019, 12:30 p.m. UTC | #1 
Hi Marek,

On 19. 3. 21. 오후 5:26, Marek Szyprowski wrote:
> Exynos Multi-Core Timer driver (exynos_mct) must be started before ARM
> Architected Timers (arch_timer), because they both share some common
> hardware blocks (global system counter) and turning on MCT is needed
> to get ARM Architected Timer working properly. Increase MCT timer rating
> and hotplug priority over ARM Archictected timer driver to achieve that.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
> ---
> v2: added comments about the relation to ARM arch timer
>     rebased onto v5.1-rc1
> v1: https://patchwork.kernel.org/patch/10814921/
> ---
>  drivers/clocksource/exynos_mct.c | 4 ++--
>  include/linux/cpuhotplug.h       | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
> index 34bd250d46c6..6aa10cbc1d59 100644
> --- a/drivers/clocksource/exynos_mct.c
> +++ b/drivers/clocksource/exynos_mct.c
> @@ -209,7 +209,7 @@ static void exynos4_frc_resume(struct clocksource *cs)
>  
>  static struct clocksource mct_frc = {
>  	.name		= "mct-frc",
> -	.rating		= 400,
> +	.rating		= 450,	/* use value higher than ARM arch timer */
>  	.read		= exynos4_frc_read,
>  	.mask		= CLOCKSOURCE_MASK(32),
>  	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
> @@ -464,7 +464,7 @@ static int exynos4_mct_starting_cpu(unsigned int cpu)
>  	evt->set_state_oneshot_stopped = set_state_shutdown;
>  	evt->tick_resume = set_state_shutdown;
>  	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
> -	evt->rating = 450;
> +	evt->rating = 500;	/* use value higher than ARM arch timer */
>  
>  	exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
>  
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index e78281d07b70..53fb48de9589 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -115,10 +115,10 @@ enum cpuhp_state {
>  	CPUHP_AP_PERF_ARM_ACPI_STARTING,
>  	CPUHP_AP_PERF_ARM_STARTING,
>  	CPUHP_AP_ARM_L2X0_STARTING,
> +	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
>  	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
>  	CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
>  	CPUHP_AP_JCORE_TIMER_STARTING,
> -	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
>  	CPUHP_AP_ARM_TWD_STARTING,
>  	CPUHP_AP_QCOM_TIMER_STARTING,
>  	CPUHP_AP_TEGRA_TIMER_STARTING,
> 

As the cover-letter, the arch-timer of Exynos SoC
used the h/w block of MCT. I agree.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Marek Szyprowski April 25, 2019, 6:29 a.m. UTC | #2 
Hi All

On 2019-03-21 09:26, Marek Szyprowski wrote:
> Exynos Multi-Core Timer driver (exynos_mct) must be started before ARM
> Architected Timers (arch_timer), because they both share some common
> hardware blocks (global system counter) and turning on MCT is needed
> to get ARM Architected Timer working properly. Increase MCT timer rating
> and hotplug priority over ARM Archictected timer driver to achieve that.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>

Thomas: could you comment or accept this change? Daniel said that he 
leaves this for you: https://patchwork.kernel.org/patch/10814921/#22486971

> ---
> v2: added comments about the relation to ARM arch timer
>      rebased onto v5.1-rc1
> v1: https://patchwork.kernel.org/patch/10814921/
> ---
>   drivers/clocksource/exynos_mct.c | 4 ++--
>   include/linux/cpuhotplug.h       | 2 +-
>   2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
> index 34bd250d46c6..6aa10cbc1d59 100644
> --- a/drivers/clocksource/exynos_mct.c
> +++ b/drivers/clocksource/exynos_mct.c
> @@ -209,7 +209,7 @@ static void exynos4_frc_resume(struct clocksource *cs)
>   
>   static struct clocksource mct_frc = {
>   	.name		= "mct-frc",
> -	.rating		= 400,
> +	.rating		= 450,	/* use value higher than ARM arch timer */
>   	.read		= exynos4_frc_read,
>   	.mask		= CLOCKSOURCE_MASK(32),
>   	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
> @@ -464,7 +464,7 @@ static int exynos4_mct_starting_cpu(unsigned int cpu)
>   	evt->set_state_oneshot_stopped = set_state_shutdown;
>   	evt->tick_resume = set_state_shutdown;
>   	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
> -	evt->rating = 450;
> +	evt->rating = 500;	/* use value higher than ARM arch timer */
>   
>   	exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
>   
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index e78281d07b70..53fb48de9589 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -115,10 +115,10 @@ enum cpuhp_state {
>   	CPUHP_AP_PERF_ARM_ACPI_STARTING,
>   	CPUHP_AP_PERF_ARM_STARTING,
>   	CPUHP_AP_ARM_L2X0_STARTING,
> +	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
>   	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
>   	CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
>   	CPUHP_AP_JCORE_TIMER_STARTING,
> -	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
>   	CPUHP_AP_ARM_TWD_STARTING,
>   	CPUHP_AP_QCOM_TIMER_STARTING,
>   	CPUHP_AP_TEGRA_TIMER_STARTING,

Best regards
diff mbox series

Patch

diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 34bd250d46c6..6aa10cbc1d59 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -209,7 +209,7 @@  static void exynos4_frc_resume(struct clocksource *cs)
 
 static struct clocksource mct_frc = {
 	.name		= "mct-frc",
-	.rating		= 400,
+	.rating		= 450,	/* use value higher than ARM arch timer */
 	.read		= exynos4_frc_read,
 	.mask		= CLOCKSOURCE_MASK(32),
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
@@ -464,7 +464,7 @@  static int exynos4_mct_starting_cpu(unsigned int cpu)
 	evt->set_state_oneshot_stopped = set_state_shutdown;
 	evt->tick_resume = set_state_shutdown;
 	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
-	evt->rating = 450;
+	evt->rating = 500;	/* use value higher than ARM arch timer */
 
 	exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
 
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index e78281d07b70..53fb48de9589 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -115,10 +115,10 @@  enum cpuhp_state {
 	CPUHP_AP_PERF_ARM_ACPI_STARTING,
 	CPUHP_AP_PERF_ARM_STARTING,
 	CPUHP_AP_ARM_L2X0_STARTING,
+	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
 	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
 	CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
 	CPUHP_AP_JCORE_TIMER_STARTING,
-	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
 	CPUHP_AP_ARM_TWD_STARTING,
 	CPUHP_AP_QCOM_TIMER_STARTING,
 	CPUHP_AP_TEGRA_TIMER_STARTING,