On Fri, Feb 04, 2011 at 04:16:07PM +0530, Santosh Shilimkar wrote: > > -----Original Message----- > > From: Russell King - ARM Linux [mailto:linux@xxxxxxxxxxxxxxxx] > > Sent: Friday, February 04, 2011 4:11 PM > > To: Santosh Shilimkar > > Cc: catalin.marinas@xxxxxxx; linus.ml.walleij@xxxxxxxxx; linux- > > omap@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > ccross@xxxxxxxxxxx > > Subject: Re: [PATCH 4/5] ARM: scu: Move register defines to header > > file > > > > On Tue, Jan 25, 2011 at 11:53:35PM +0530, Santosh Shilimkar wrote: > > > After fixing the 3rd version for base address break, I was able to > > > use this patch and test it. Seems to work. SMC related stuff can > > > be ignored because OMAP4 ES1.0 doesn't have functional PM hardware > > > support. > > > > I think I'd prefer to do as the other functions do, and pass in the > > scu base address from the platform code. It's potentially more > > efficient for platforms which have a fixed SCU base address. > Ok. I can fix that 8<------ Subject: [PATCH] ARM: smp: add function to set WFI low-power mode for SMP CPUs Add a function to set the SCU low-power mode for SMP CPUs. This centralizes this functionality rather than having to expose the SCU register definitions to each platform. Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> --- arch/arm/include/asm/smp_scu.h | 5 +++++ arch/arm/kernel/smp_scu.c | 24 ++++++++++++++++++++++++ 2 files changed, 29 insertions(+), 0 deletions(-) diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h index 2376835..800860d 100644 --- a/arch/arm/include/asm/smp_scu.h +++ b/arch/arm/include/asm/smp_scu.h @@ -1,7 +1,12 @@ #ifndef __ASMARM_ARCH_SCU_H #define __ASMARM_ARCH_SCU_H +#define SCU_PM_NORMAL 0 +#define SCU_PM_DORMANT 2 +#define SCU_PM_POWEROFF 3 + unsigned int scu_get_core_count(void __iomem *); void scu_enable(void __iomem *); +int scu_power_mode(void __iomem *, unsigned int); #endif diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c index 9ab4149..0ba329a 100644 --- a/arch/arm/kernel/smp_scu.c +++ b/arch/arm/kernel/smp_scu.c @@ -50,3 +50,27 @@ void __init scu_enable(void __iomem *scu_base) */ flush_cache_all(); } + +/* + * Set the executing CPUs power mode as defined. This will be in + * preparation for it executing a WFI instruction. + * + * This function must be called with preemption disabled, and as it + * has the side effect of disabling coherency, caches must have been + * flushed. Interrupts must also have been disabled. + */ +int scu_power_mode(void __iomem *scu_base, unsigned int mode) +{ + unsigned int val; + int cpu = smp_processor_id(); + int shift; + + if (mode > 3 || mode == 1 || cpu > 3) + return -EINVAL; + + val = __raw_readb(scu_base + SCU_CPU_STATUS + cpu) & ~0x03; + val |= mode; + __raw_writeb(val, scu_base + SCU_CPU_STATUS + cpu); + + return 0; +} -- 1.6.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
