Hi,
On Mon, May 20, 2013 at 3:33 PM, Sanjay Singh Rawat <sanjay.rawat@linaro.org
wrote:
Add function which prepare arm processors to enter the low power for hotplug functionality and handle the return path.
Signed-off-by: Sanjay Singh Rawat sanjay.rawat@linaro.org
arch/arm/include/asm/hotplug.h | 24 +++++++++++++++ arch/arm/kernel/Makefile | 1 + arch/arm/kernel/cpuhotplug.c | 64 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 89 insertions(+) create mode 100644 arch/arm/include/asm/hotplug.h create mode 100644 arch/arm/kernel/cpuhotplug.c
diff --git a/arch/arm/include/asm/hotplug.h b/arch/arm/include/asm/hotplug.h new file mode 100644 index 0000000..ae80f0e --- /dev/null +++ b/arch/arm/include/asm/hotplug.h @@ -0,0 +1,24 @@ +/*
- arch/arm/include/asm/hotplug.h
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License version 2 as
- published by the Free Software Foundation.
- */
+#ifdef CONFIG_HOTPLUG_CPU
+extern inline void cpu_enter_lowpower(void); +extern inline void cpu_leave_lowpower(void);
+#else +static inline void cpu_enter_lowpower(void) +{
return -ENODEV;+} +static inline void cpu_leave_lowpower(void) +{
return -ENODEV;+}
+#endif diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 5f3338e..9bd370b 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -33,6 +33,7 @@ obj-$(CONFIG_ISA_DMA) += dma-isa.o obj-$(CONFIG_PCI) += bios32.o isa.o obj-$(CONFIG_ARM_CPU_SUSPEND) += sleep.o suspend.o obj-$(CONFIG_SMP) += smp.o smp_tlb.o +obj-$(CONFIG_HOTPLUG_CPU) += cpuhotplug.o obj-$(CONFIG_HAVE_ARM_SCU) += smp_scu.o obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o obj-$(CONFIG_ARM_ARCH_TIMER) += arch_timer.o diff --git a/arch/arm/kernel/cpuhotplug.c b/arch/arm/kernel/cpuhotplug.c new file mode 100644 index 0000000..8651b96 --- /dev/null +++ b/arch/arm/kernel/cpuhotplug.c @@ -0,0 +1,64 @@ +/*
- Copyright (C) 2002 ARM Ltd.
- All Rights Reserved
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License version 2 as
- published by the Free Software Foundation.
- */
+#include <linux/kernel.h> +#include <asm/cp15.h>
+/*
- For Cortex-A9 processor
- */
+static inline void ca9_enter_lowpower(void) +{
unsigned int v;asm volatile(" mcr p15, 0, %1, c7, c5, 0\n"" mcr p15, 0, %1, c7, c10, 4\n"/** Turn off coherency*/" mrc p15, 0, %0, c1, c0, 1\n"" bic %0, %0, %3\n"" mcr p15, 0, %0, c1, c0, 1\n"" mrc p15, 0, %0, c1, c0, 0\n"" bic %0, %0, %2\n"" mcr p15, 0, %0, c1, c0, 0\n": "=&r" (v): "r" (0), "Ir" (CR_C), "Ir" (0x40): "cc");+}
+inline void cpu_leave_lowpower(void) +{
unsigned int v;asm volatile("mrc p15, 0, %0, c1, c0, 0\n"" orr %0, %0, %1\n"" mcr p15, 0, %0, c1, c0, 0\n"" mrc p15, 0, %0, c1, c0, 1\n"" orr %0, %0, %2\n"" mcr p15, 0, %0, c1, c0, 1\n": "=&r" (v): "Ir" (CR_C), "Ir" (0x40): "cc");+}
+void cpu_enter_lowpower(void) +{
int id = 0;/* check the cpuid */asm("mrc p15, 0, %0, c0, c0, 0" : "=r"(id) : : "cc");
do you want to call it every time? doesn't better to run it once and use the variable? or make function pointer and use it.
if ((id & 0xffffffff) == 0x411fc090)ca9_enter_lowpower();elsepr_warn(KERN_WARNING "Unknown CPU type\n");+}
Thank you, Kyungmin Park
-- 1.7.9.5
linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev