[RFC/PATCH 0/4] Add cpuidle support for r8a7791

[RFC/PATCH 0/4] Add cpuidle support for r8a7791

[Keita Kobayashi]

Hello

These patches add cpuidle support for Renesas r8a7791 SoC.
The r8a7791 cpuidle supports WFI and the cpu power state(Core-Standby)
using Generic ARM CPU idle driver(cpuidle-arm).

Based on : next-20150402
Tested on : koelsch board

Keita Kobayashi (4):
  ARM: cpuidle: Add cpuidle support for R-Car Gen2 series
  ARM: shmobile: Add cpuidle_ops for R-Car cpuidle
  ARM: shmobile: dtsi: Add cpuidle parameters into each cpu for r8a7791
  ARM: shmobile: Enable Renesas R-Car cpuidle for shmobile_defconfig

 arch/arm/boot/dts/r8a7791.dtsi        | 13 +++++++++++++
 arch/arm/configs/shmobile_defconfig   |  2 ++
 arch/arm/mach-shmobile/platsmp-apmu.c | 11 +++++++++--
 arch/arm/mach-shmobile/platsmp-apmu.h |  1 +
 arch/arm/mach-shmobile/pm-rcar-gen2.c | 17 +++++++++++++++++
 drivers/cpuidle/Kconfig.arm           |  8 ++++++++
 6 files changed, 50 insertions(+), 2 deletions(-)

-- 
1.9.1

[RFC/PATCH 1/4] ARM: cpuidle: Add cpuidle support for R-Car Gen2 series

[Keita Kobayashi]

Define ARM_RCAR_CPUIDLE config item to enable cpuidle
support for Renesas R-Car Gen2 SoCs.

Signed-off-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
---
 drivers/cpuidle/Kconfig.arm | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
index 21340e0..ea9d61e 100644
--- a/drivers/cpuidle/Kconfig.arm
+++ b/drivers/cpuidle/Kconfig.arm
@@ -74,3 +74,11 @@ config ARM_MVEBU_V7_CPUIDLE
 	depends on ARCH_MVEBU && !ARM64
 	help
 	  Select this to enable cpuidle on Armada 370, 38x and XP processors.
+
+config ARM_RCAR_CPUIDLE
+	bool "CPU Idle Driver for the R-Car SoCs"
+	depends on ARCH_RCAR_GEN2
+	select ARM_CPUIDLE
+	select ARM_CPU_SUSPEND
+	help
+	  Select this to enable cpuidle for R-Car SoCs
-- 
1.9.1

Re: [RFC/PATCH 1/4] ARM: cpuidle: Add cpuidle support for R-Car Gen2 series

[Simon Horman]

On Mon, Apr 06, 2015 at 12:50:41PM +0900, Keita Kobayashi wrote:
> Define ARM_RCAR_CPUIDLE config item to enable cpuidle
> support for Renesas R-Car Gen2 SoCs.
> 
> Signed-off-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
> ---
>  drivers/cpuidle/Kconfig.arm | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
> index 21340e0..ea9d61e 100644
> --- a/drivers/cpuidle/Kconfig.arm
> +++ b/drivers/cpuidle/Kconfig.arm
> @@ -74,3 +74,11 @@ config ARM_MVEBU_V7_CPUIDLE
>  	depends on ARCH_MVEBU && !ARM64
>  	help
>  	  Select this to enable cpuidle on Armada 370, 38x and XP processors.
> +
> +config ARM_RCAR_CPUIDLE
> +	bool "CPU Idle Driver for the R-Car SoCs"
> +	depends on ARCH_RCAR_GEN2
> +	select ARM_CPUIDLE
> +	select ARM_CPU_SUSPEND
> +	help
> +	  Select this to enable cpuidle for R-Car SoCs

I hate to be the harbinger of bad news but I don't believe this will
reliably work because ARM_CPUIDLE selects DT_IDLE_STATES and I believe that
Kconfig does not support recursive selection[1].

[1] http://lkml.iu.edu/hypermail/linux/kernel/1412.0/04004.html

I suggest changing select ARM_CPUIDLE to depends on ARM_CPUIDLE.
I would be tempted to make the same change for ARM_CPU_SUSPEND too.

Re: [RFC/PATCH 1/4] ARM: cpuidle: Add cpuidle support for R-Car Gen2 series

[keita kobayashi]

Hi Simon

Thank you for your feedback.

(2015/04/07 10:44), Simon Horman wrote:

> On Mon, Apr 06, 2015 at 12:50:41PM +0900, Keita Kobayashi wrote:
>> Define ARM_RCAR_CPUIDLE config item to enable cpuidle
>> support for Renesas R-Car Gen2 SoCs.
>>
>> Signed-off-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
>> ---
>>  drivers/cpuidle/Kconfig.arm | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
>> index 21340e0..ea9d61e 100644
>> --- a/drivers/cpuidle/Kconfig.arm
>> +++ b/drivers/cpuidle/Kconfig.arm
>> @@ -74,3 +74,11 @@ config ARM_MVEBU_V7_CPUIDLE
>>  	depends on ARCH_MVEBU && !ARM64
>>  	help
>>  	  Select this to enable cpuidle on Armada 370, 38x and XP processors.
>> +
>> +config ARM_RCAR_CPUIDLE
>> +	bool "CPU Idle Driver for the R-Car SoCs"
>> +	depends on ARCH_RCAR_GEN2
>> +	select ARM_CPUIDLE
>> +	select ARM_CPU_SUSPEND
>> +	help
>> +	  Select this to enable cpuidle for R-Car SoCs
> 
> I hate to be the harbinger of bad news but I don't believe this will
> reliably work because ARM_CPUIDLE selects DT_IDLE_STATES and I believe that
> Kconfig does not support recursive selection[1].
> 
> [1] http://lkml.iu.edu/hypermail/linux/kernel/1412.0/04004.html
> 
> I suggest changing select ARM_CPUIDLE to depends on ARM_CPUIDLE.
> I would be tempted to make the same change for ARM_CPU_SUSPEND too.

I will fix it with V2 patch.

Regards.
Keita Kobayashi

[RFC/PATCH 3/4] ARM: shmobile: dtsi: Add cpuidle parameters into each cpu for r8a7791

[Keita Kobayashi]

This patch add enable-method node and idle-states node for r8a7791.

Signed-off-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
---
 arch/arm/boot/dts/r8a7791.dtsi | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm/boot/dts/r8a7791.dtsi b/arch/arm/boot/dts/r8a7791.dtsi
index 4696062..fd17866 100644
--- a/arch/arm/boot/dts/r8a7791.dtsi
+++ b/arch/arm/boot/dts/r8a7791.dtsi
@@ -46,11 +46,13 @@
 		cpu0: cpu@0 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a15";
+			enable-method = "renesas,rcar-idle";
 			reg = <0>;
 			clock-frequency = <1500000000>;
 			voltage-tolerance = <1>; /* 1% */
 			clocks = <&cpg_clocks R8A7791_CLK_Z>;
 			clock-latency = <300000>; /* 300 us */
+			cpu-idle-states = <&CORE_STANDBY>;
 
 			/* kHz - uV - OPPs unknown yet */
 			operating-points = <1500000 1000000>,
@@ -64,8 +66,19 @@
 		cpu1: cpu@1 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a15";
+			enable-method = "renesas,rcar-idle";
 			reg = <1>;
 			clock-frequency = <1500000000>;
+			cpu-idle-states = <&CORE_STANDBY>;
+		};
+
+		idle-states {
+			CORE_STANDBY: CoreStandby {
+				compatible = "arm,idle-state";
+				entry-latency-us = <500>;
+				exit-latency-us = <2300>;
+				min-residency-us = <2800>;
+			};
 		};
 	};
 
-- 
1.9.1

[RFC/PATCH 4/4] ARM: shmobile: Enable Renesas R-Car cpuidle for shmobile_defconfig

[Keita Kobayashi]

Signed-off-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
---
 arch/arm/configs/shmobile_defconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/configs/shmobile_defconfig b/arch/arm/configs/shmobile_defconfig
index b58618e..e487045 100644
--- a/arch/arm/configs/shmobile_defconfig
+++ b/arch/arm/configs/shmobile_defconfig
@@ -44,6 +44,8 @@ CONFIG_CPU_FREQ_GOV_USERSPACE=y
 CONFIG_CPU_FREQ_GOV_ONDEMAND=y
 CONFIG_CPU_FREQ_GOV_CONSERVATIVE=y
 CONFIG_CPUFREQ_DT=y
+CONFIG_CPU_IDLE=y
+CONFIG_ARM_RCAR_CPUIDLE=y
 CONFIG_VFP=y
 CONFIG_NEON=y
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
-- 
1.9.1