| Message ID | 1406275790-18617-3-git-send-email-shawn.guo@freescale.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jul 25, 2014 at 04:09:50PM +0800, Shawn Guo wrote: > With SCU standby enabled, SCU CLK will be turned off when all processors > are in WFI mode. And the clock will be turned on when any processor > leaves WFI mode. > > This behavior should be preferable in terms of power efficiency of > system idle. So let's set the SCU standby bit to enable the support in > function scu_enable(). > > Cortex-A9 earlier than r2p0 has no standby bit in SCU, so we need to > skip setting the bit for those. > > Signed-off-by: Shawn Guo <shawn.guo@freescale.com> If there is no objection on the patch, I will put it into patch tracker soon. Russell, I know it's late for 3.17 at this point, and I'm fine that you queue it for 3.18. Shawn > --- > arch/arm/kernel/smp_scu.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c > index c947508f84e6..72f9241ad5db 100644 > --- a/arch/arm/kernel/smp_scu.c > +++ b/arch/arm/kernel/smp_scu.c > @@ -18,6 +18,7 @@ > > #define SCU_CTRL 0x00 > #define SCU_ENABLE (1 << 0) > +#define SCU_STANDBY_ENABLE (1 << 5) > #define SCU_CONFIG 0x04 > #define SCU_CPU_STATUS 0x08 > #define SCU_INVALIDATE 0x0c > @@ -55,6 +56,12 @@ void scu_enable(void __iomem *scu_base) > return; > > scu_ctrl |= SCU_ENABLE; > + > + /* Cortex-A9 earlier than r2p0 has no standby bit in SCU */ > + if ((read_cpuid_id() & 0xff0ffff0) == 0x410fc090 && > + (read_cpuid_id() & 0x00f0000f) >= 0x00200000) > + scu_ctrl |= SCU_STANDBY_ENABLE; > + > writel_relaxed(scu_ctrl, scu_base + SCU_CTRL); > > /* > -- > 1.9.1 >
On Tue, Jul 29, 2014 at 08:44:11PM +0800, Shawn Guo wrote: > On Fri, Jul 25, 2014 at 04:09:50PM +0800, Shawn Guo wrote: > > With SCU standby enabled, SCU CLK will be turned off when all processors > > are in WFI mode. And the clock will be turned on when any processor > > leaves WFI mode. > > > > This behavior should be preferable in terms of power efficiency of > > system idle. So let's set the SCU standby bit to enable the support in > > function scu_enable(). > > > > Cortex-A9 earlier than r2p0 has no standby bit in SCU, so we need to > > skip setting the bit for those. > > > > Signed-off-by: Shawn Guo <shawn.guo@freescale.com> > > If there is no objection on the patch, I will put it into patch tracker > soon. Submitted these two patches as #8121 and #8122. Shawn
diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c index c947508f84e6..72f9241ad5db 100644 --- a/arch/arm/kernel/smp_scu.c +++ b/arch/arm/kernel/smp_scu.c @@ -18,6 +18,7 @@ #define SCU_CTRL 0x00 #define SCU_ENABLE (1 << 0) +#define SCU_STANDBY_ENABLE (1 << 5) #define SCU_CONFIG 0x04 #define SCU_CPU_STATUS 0x08 #define SCU_INVALIDATE 0x0c @@ -55,6 +56,12 @@ void scu_enable(void __iomem *scu_base) return; scu_ctrl |= SCU_ENABLE; + + /* Cortex-A9 earlier than r2p0 has no standby bit in SCU */ + if ((read_cpuid_id() & 0xff0ffff0) == 0x410fc090 && + (read_cpuid_id() & 0x00f0000f) >= 0x00200000) + scu_ctrl |= SCU_STANDBY_ENABLE; + writel_relaxed(scu_ctrl, scu_base + SCU_CTRL); /*
With SCU standby enabled, SCU CLK will be turned off when all processors are in WFI mode. And the clock will be turned on when any processor leaves WFI mode. This behavior should be preferable in terms of power efficiency of system idle. So let's set the SCU standby bit to enable the support in function scu_enable(). Cortex-A9 earlier than r2p0 has no standby bit in SCU, so we need to skip setting the bit for those. Signed-off-by: Shawn Guo <shawn.guo@freescale.com> --- arch/arm/kernel/smp_scu.c | 7 +++++++ 1 file changed, 7 insertions(+)