| Message ID | 1407235425-13937-1-git-send-email-k.kozlowski@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 08/05/2014 12:43 PM, Krzysztof Kozlowski wrote: > Cleanup a little the SMP/hotplug code for Exynos by: > 1. Moving completely all functions from hotplug.c into the platsmp.c; > 2. Deleting the hotplug.c file. > > After recent cleanups (e.g. 75ad2ab28f0f "ARM: EXYNOS: use > v7_exit_coherency_flush macro for cache disabling") there was only CPU > power down related code in hotplug.c file. Keeping this file does not > give any benefits. > > The commit only moves code around with one additional observable change: > the hotplug.c was compiled with custom CFLAGS (-march=armv7-a). These > CFLAGS are not necessary any more. What is the benefit of moving this code around ? Usually the cpu hotplug code is located in hotplug.c for most of the platforms, so why moving pm code inside platsmp ? > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > Reviewed-by: Tomasz Figa <t.figa@samsung.com> > > --- > Changes since v4: > 1. Rebase on linux-next-20140804. > 2. Add Reviewed-by Tomasz Figa. > --- > arch/arm/mach-exynos/Makefile | 3 -- > arch/arm/mach-exynos/common.h | 2 - > arch/arm/mach-exynos/hotplug.c | 91 ------------------------------------------ > arch/arm/mach-exynos/platsmp.c | 74 ++++++++++++++++++++++++++++++++++ > 4 files changed, 74 insertions(+), 96 deletions(-) > delete mode 100644 arch/arm/mach-exynos/hotplug.c > > diff --git a/arch/arm/mach-exynos/Makefile b/arch/arm/mach-exynos/Makefile > index 788f26d21141..0095de99d703 100644 > --- a/arch/arm/mach-exynos/Makefile > +++ b/arch/arm/mach-exynos/Makefile > @@ -21,9 +21,6 @@ obj-$(CONFIG_PM_GENERIC_DOMAINS) += pm_domains.o > > obj-$(CONFIG_SMP) += platsmp.o headsmp.o > > -obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o > -CFLAGS_hotplug.o += -march=armv7-a > - > plus_sec := $(call as-instr,.arch_extension sec,+sec) > AFLAGS_exynos-smc.o :=-Wa,-march=armv7-a$(plus_sec) > > diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h > index 47b904b3b973..3d3e6af9d015 100644 > --- a/arch/arm/mach-exynos/common.h > +++ b/arch/arm/mach-exynos/common.h > @@ -130,8 +130,6 @@ extern void exynos_cpu_resume(void); > > extern struct smp_operations exynos_smp_ops; > > -extern void exynos_cpu_die(unsigned int cpu); > - > /* PMU(Power Management Unit) support */ > > #define PMU_TABLE_END (-1U) > diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c > deleted file mode 100644 > index 4d86961a7957..000000000000 > --- a/arch/arm/mach-exynos/hotplug.c > +++ /dev/null > @@ -1,91 +0,0 @@ > -/* > - * Cloned from linux/arch/arm/mach-realview/hotplug.c > - * > - * 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 <linux/errno.h> > -#include <linux/smp.h> > -#include <linux/io.h> > - > -#include <asm/cacheflush.h> > -#include <asm/cp15.h> > -#include <asm/smp_plat.h> > - > -#include "common.h" > -#include "regs-pmu.h" > - > -static 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"); > -} > - > -static inline void platform_do_lowpower(unsigned int cpu, int *spurious) > -{ > - u32 mpidr = cpu_logical_map(cpu); > - u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); > - > - for (;;) { > - > - /* Turn the CPU off on next WFI instruction. */ > - exynos_cpu_power_down(core_id); > - > - wfi(); > - > - if (pen_release == core_id) { > - /* > - * OK, proper wakeup, we're done > - */ > - break; > - } > - > - /* > - * Getting here, means that we have come out of WFI without > - * having been woken up - this shouldn't happen > - * > - * Just note it happening - when we're woken, we can report > - * its occurrence. > - */ > - (*spurious)++; > - } > -} > - > -/* > - * platform-specific code to shutdown a CPU > - * > - * Called with IRQs disabled > - */ > -void __ref exynos_cpu_die(unsigned int cpu) > -{ > - int spurious = 0; > - > - v7_exit_coherency_flush(louis); > - > - platform_do_lowpower(cpu, &spurious); > - > - /* > - * bring this CPU back into the world of cache > - * coherency, and then restore interrupts > - */ > - cpu_leave_lowpower(); > - > - if (spurious) > - pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); > -} > diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c > index a9f1cf759949..a809f76c8160 100644 > --- a/arch/arm/mach-exynos/platsmp.c > +++ b/arch/arm/mach-exynos/platsmp.c > @@ -22,6 +22,7 @@ > #include <linux/of_address.h> > > #include <asm/cacheflush.h> > +#include <asm/cp15.h> > #include <asm/smp_plat.h> > #include <asm/smp_scu.h> > #include <asm/firmware.h> > @@ -33,6 +34,54 @@ > > extern void exynos4_secondary_startup(void); > > +#ifdef CONFIG_HOTPLUG_CPU > +static 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"); > +} > + > +static inline void platform_do_lowpower(unsigned int cpu, int *spurious) > +{ > + u32 mpidr = cpu_logical_map(cpu); > + u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); > + > + for (;;) { > + > + /* Turn the CPU off on next WFI instruction. */ > + exynos_cpu_power_down(core_id); > + > + wfi(); > + > + if (pen_release == core_id) { > + /* > + * OK, proper wakeup, we're done > + */ > + break; > + } > + > + /* > + * Getting here, means that we have come out of WFI without > + * having been woken up - this shouldn't happen > + * > + * Just note it happening - when we're woken, we can report > + * its occurrence. > + */ > + (*spurious)++; > + } > +} > +#endif /* CONFIG_HOTPLUG_CPU */ > + > /** > * exynos_core_power_down : power down the specified cpu > * @cpu : the cpu to power down > @@ -318,6 +367,31 @@ static void __init exynos_smp_prepare_cpus(unsigned int max_cpus) > } > } > > +#ifdef CONFIG_HOTPLUG_CPU > +/* > + * platform-specific code to shutdown a CPU > + * > + * Called with IRQs disabled > + */ > +static void __ref exynos_cpu_die(unsigned int cpu) > +{ > + int spurious = 0; > + > + v7_exit_coherency_flush(louis); > + > + platform_do_lowpower(cpu, &spurious); > + > + /* > + * bring this CPU back into the world of cache > + * coherency, and then restore interrupts > + */ > + cpu_leave_lowpower(); > + > + if (spurious) > + pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); > +} > +#endif /* CONFIG_HOTPLUG_CPU */ > + > struct smp_operations exynos_smp_ops __initdata = { > .smp_init_cpus = exynos_smp_init_cpus, > .smp_prepare_cpus = exynos_smp_prepare_cpus, >
On wto, 2014-08-05 at 16:46 +0200, Daniel Lezcano wrote: > On 08/05/2014 12:43 PM, Krzysztof Kozlowski wrote: > > Cleanup a little the SMP/hotplug code for Exynos by: > > 1. Moving completely all functions from hotplug.c into the platsmp.c; > > 2. Deleting the hotplug.c file. > > > > After recent cleanups (e.g. 75ad2ab28f0f "ARM: EXYNOS: use > > v7_exit_coherency_flush macro for cache disabling") there was only CPU > > power down related code in hotplug.c file. Keeping this file does not > > give any benefits. > > > > The commit only moves code around with one additional observable change: > > the hotplug.c was compiled with custom CFLAGS (-march=armv7-a). These > > CFLAGS are not necessary any more. > > What is the benefit of moving this code around ? > > Usually the cpu hotplug code is located in hotplug.c for most of the > platforms, so why moving pm code inside platsmp ? The benefits are: 1. Less dependencies, cleaner code because platsmp.c is the only user of code located in hotplug.c. So the exynos_cpu_die() had to be declared in common.h. 2. Less dependencies between modules after adding patch 3/3 [1] which introduces exynos_set_delayed_reset_assertion() function. The exynos_set_delayed_reset_assertion() is called by: - cpu_leave_power (hotplug.c) - platform_do_lowpower (hotplug.c) - exynos_boot_secondary (platsmp.c) so merging everything into one file seemed simpler and cleaner. However I do not insist on such solution. I'm merely interested in getting the third patch into the kernel :) . [1] http://www.spinics.net/lists/arm-kernel/msg352890.html Best regards, Krzysztof > > > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > > Reviewed-by: Tomasz Figa <t.figa@samsung.com> > > > > --- > > Changes since v4: > > 1. Rebase on linux-next-20140804. > > 2. Add Reviewed-by Tomasz Figa. > > --- > > arch/arm/mach-exynos/Makefile | 3 -- > > arch/arm/mach-exynos/common.h | 2 - > > arch/arm/mach-exynos/hotplug.c | 91 ------------------------------------------ > > arch/arm/mach-exynos/platsmp.c | 74 ++++++++++++++++++++++++++++++++++ > > 4 files changed, 74 insertions(+), 96 deletions(-) > > delete mode 100644 arch/arm/mach-exynos/hotplug.c > > > > diff --git a/arch/arm/mach-exynos/Makefile b/arch/arm/mach-exynos/Makefile > > index 788f26d21141..0095de99d703 100644 > > --- a/arch/arm/mach-exynos/Makefile > > +++ b/arch/arm/mach-exynos/Makefile > > @@ -21,9 +21,6 @@ obj-$(CONFIG_PM_GENERIC_DOMAINS) += pm_domains.o > > > > obj-$(CONFIG_SMP) += platsmp.o headsmp.o > > > > -obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o > > -CFLAGS_hotplug.o += -march=armv7-a > > - > > plus_sec := $(call as-instr,.arch_extension sec,+sec) > > AFLAGS_exynos-smc.o :=-Wa,-march=armv7-a$(plus_sec) > > > > diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h > > index 47b904b3b973..3d3e6af9d015 100644 > > --- a/arch/arm/mach-exynos/common.h > > +++ b/arch/arm/mach-exynos/common.h > > @@ -130,8 +130,6 @@ extern void exynos_cpu_resume(void); > > > > extern struct smp_operations exynos_smp_ops; > > > > -extern void exynos_cpu_die(unsigned int cpu); > > - > > /* PMU(Power Management Unit) support */ > > > > #define PMU_TABLE_END (-1U) > > diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c > > deleted file mode 100644 > > index 4d86961a7957..000000000000 > > --- a/arch/arm/mach-exynos/hotplug.c > > +++ /dev/null > > @@ -1,91 +0,0 @@ > > -/* > > - * Cloned from linux/arch/arm/mach-realview/hotplug.c > > - * > > - * 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 <linux/errno.h> > > -#include <linux/smp.h> > > -#include <linux/io.h> > > - > > -#include <asm/cacheflush.h> > > -#include <asm/cp15.h> > > -#include <asm/smp_plat.h> > > - > > -#include "common.h" > > -#include "regs-pmu.h" > > - > > -static 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"); > > -} > > - > > -static inline void platform_do_lowpower(unsigned int cpu, int *spurious) > > -{ > > - u32 mpidr = cpu_logical_map(cpu); > > - u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); > > - > > - for (;;) { > > - > > - /* Turn the CPU off on next WFI instruction. */ > > - exynos_cpu_power_down(core_id); > > - > > - wfi(); > > - > > - if (pen_release == core_id) { > > - /* > > - * OK, proper wakeup, we're done > > - */ > > - break; > > - } > > - > > - /* > > - * Getting here, means that we have come out of WFI without > > - * having been woken up - this shouldn't happen > > - * > > - * Just note it happening - when we're woken, we can report > > - * its occurrence. > > - */ > > - (*spurious)++; > > - } > > -} > > - > > -/* > > - * platform-specific code to shutdown a CPU > > - * > > - * Called with IRQs disabled > > - */ > > -void __ref exynos_cpu_die(unsigned int cpu) > > -{ > > - int spurious = 0; > > - > > - v7_exit_coherency_flush(louis); > > - > > - platform_do_lowpower(cpu, &spurious); > > - > > - /* > > - * bring this CPU back into the world of cache > > - * coherency, and then restore interrupts > > - */ > > - cpu_leave_lowpower(); > > - > > - if (spurious) > > - pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); > > -} > > diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c > > index a9f1cf759949..a809f76c8160 100644 > > --- a/arch/arm/mach-exynos/platsmp.c > > +++ b/arch/arm/mach-exynos/platsmp.c > > @@ -22,6 +22,7 @@ > > #include <linux/of_address.h> > > > > #include <asm/cacheflush.h> > > +#include <asm/cp15.h> > > #include <asm/smp_plat.h> > > #include <asm/smp_scu.h> > > #include <asm/firmware.h> > > @@ -33,6 +34,54 @@ > > > > extern void exynos4_secondary_startup(void); > > > > +#ifdef CONFIG_HOTPLUG_CPU > > +static 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"); > > +} > > + > > +static inline void platform_do_lowpower(unsigned int cpu, int *spurious) > > +{ > > + u32 mpidr = cpu_logical_map(cpu); > > + u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); > > + > > + for (;;) { > > + > > + /* Turn the CPU off on next WFI instruction. */ > > + exynos_cpu_power_down(core_id); > > + > > + wfi(); > > + > > + if (pen_release == core_id) { > > + /* > > + * OK, proper wakeup, we're done > > + */ > > + break; > > + } > > + > > + /* > > + * Getting here, means that we have come out of WFI without > > + * having been woken up - this shouldn't happen > > + * > > + * Just note it happening - when we're woken, we can report > > + * its occurrence. > > + */ > > + (*spurious)++; > > + } > > +} > > +#endif /* CONFIG_HOTPLUG_CPU */ > > + > > /** > > * exynos_core_power_down : power down the specified cpu > > * @cpu : the cpu to power down > > @@ -318,6 +367,31 @@ static void __init exynos_smp_prepare_cpus(unsigned int max_cpus) > > } > > } > > > > +#ifdef CONFIG_HOTPLUG_CPU > > +/* > > + * platform-specific code to shutdown a CPU > > + * > > + * Called with IRQs disabled > > + */ > > +static void __ref exynos_cpu_die(unsigned int cpu) > > +{ > > + int spurious = 0; > > + > > + v7_exit_coherency_flush(louis); > > + > > + platform_do_lowpower(cpu, &spurious); > > + > > + /* > > + * bring this CPU back into the world of cache > > + * coherency, and then restore interrupts > > + */ > > + cpu_leave_lowpower(); > > + > > + if (spurious) > > + pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); > > +} > > +#endif /* CONFIG_HOTPLUG_CPU */ > > + > > struct smp_operations exynos_smp_ops __initdata = { > > .smp_init_cpus = exynos_smp_init_cpus, > > .smp_prepare_cpus = exynos_smp_prepare_cpus, > > > >
On 05.08.2014 17:03, Krzysztof Kozlowski wrote: > On wto, 2014-08-05 at 16:46 +0200, Daniel Lezcano wrote: >> On 08/05/2014 12:43 PM, Krzysztof Kozlowski wrote: >>> Cleanup a little the SMP/hotplug code for Exynos by: >>> 1. Moving completely all functions from hotplug.c into the platsmp.c; >>> 2. Deleting the hotplug.c file. >>> >>> After recent cleanups (e.g. 75ad2ab28f0f "ARM: EXYNOS: use >>> v7_exit_coherency_flush macro for cache disabling") there was only CPU >>> power down related code in hotplug.c file. Keeping this file does not >>> give any benefits. >>> >>> The commit only moves code around with one additional observable change: >>> the hotplug.c was compiled with custom CFLAGS (-march=armv7-a). These >>> CFLAGS are not necessary any more. >> >> What is the benefit of moving this code around ? >> >> Usually the cpu hotplug code is located in hotplug.c for most of the >> platforms, so why moving pm code inside platsmp ? > > The benefits are: > > 1. Less dependencies, cleaner code because platsmp.c is the only user of > code located in hotplug.c. So the exynos_cpu_die() had to be declared in > common.h. > > 2. Less dependencies between modules after adding patch 3/3 [1] which > introduces exynos_set_delayed_reset_assertion() function. The > exynos_set_delayed_reset_assertion() is called by: > - cpu_leave_power (hotplug.c) > - platform_do_lowpower (hotplug.c) > - exynos_boot_secondary (platsmp.c) > > so merging everything into one file seemed simpler and cleaner. mach-exynos/hotplug.c does not have too much code right now and as Krzysztof noticed the only user of functions from it is platsmp.c anyway. We don't need to follow other machs in something that makes no sense, so Acked-by: Tomasz Figa <t.figa@samsung.com> Best regards, Tomasz
diff --git a/arch/arm/mach-exynos/Makefile b/arch/arm/mach-exynos/Makefile index 788f26d21141..0095de99d703 100644 --- a/arch/arm/mach-exynos/Makefile +++ b/arch/arm/mach-exynos/Makefile @@ -21,9 +21,6 @@ obj-$(CONFIG_PM_GENERIC_DOMAINS) += pm_domains.o obj-$(CONFIG_SMP) += platsmp.o headsmp.o -obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o -CFLAGS_hotplug.o += -march=armv7-a - plus_sec := $(call as-instr,.arch_extension sec,+sec) AFLAGS_exynos-smc.o :=-Wa,-march=armv7-a$(plus_sec) diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h index 47b904b3b973..3d3e6af9d015 100644 --- a/arch/arm/mach-exynos/common.h +++ b/arch/arm/mach-exynos/common.h @@ -130,8 +130,6 @@ extern void exynos_cpu_resume(void); extern struct smp_operations exynos_smp_ops; -extern void exynos_cpu_die(unsigned int cpu); - /* PMU(Power Management Unit) support */ #define PMU_TABLE_END (-1U) diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c deleted file mode 100644 index 4d86961a7957..000000000000 --- a/arch/arm/mach-exynos/hotplug.c +++ /dev/null @@ -1,91 +0,0 @@ -/* - * Cloned from linux/arch/arm/mach-realview/hotplug.c - * - * 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 <linux/errno.h> -#include <linux/smp.h> -#include <linux/io.h> - -#include <asm/cacheflush.h> -#include <asm/cp15.h> -#include <asm/smp_plat.h> - -#include "common.h" -#include "regs-pmu.h" - -static 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"); -} - -static inline void platform_do_lowpower(unsigned int cpu, int *spurious) -{ - u32 mpidr = cpu_logical_map(cpu); - u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); - - for (;;) { - - /* Turn the CPU off on next WFI instruction. */ - exynos_cpu_power_down(core_id); - - wfi(); - - if (pen_release == core_id) { - /* - * OK, proper wakeup, we're done - */ - break; - } - - /* - * Getting here, means that we have come out of WFI without - * having been woken up - this shouldn't happen - * - * Just note it happening - when we're woken, we can report - * its occurrence. - */ - (*spurious)++; - } -} - -/* - * platform-specific code to shutdown a CPU - * - * Called with IRQs disabled - */ -void __ref exynos_cpu_die(unsigned int cpu) -{ - int spurious = 0; - - v7_exit_coherency_flush(louis); - - platform_do_lowpower(cpu, &spurious); - - /* - * bring this CPU back into the world of cache - * coherency, and then restore interrupts - */ - cpu_leave_lowpower(); - - if (spurious) - pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); -} diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c index a9f1cf759949..a809f76c8160 100644 --- a/arch/arm/mach-exynos/platsmp.c +++ b/arch/arm/mach-exynos/platsmp.c @@ -22,6 +22,7 @@ #include <linux/of_address.h> #include <asm/cacheflush.h> +#include <asm/cp15.h> #include <asm/smp_plat.h> #include <asm/smp_scu.h> #include <asm/firmware.h> @@ -33,6 +34,54 @@ extern void exynos4_secondary_startup(void); +#ifdef CONFIG_HOTPLUG_CPU +static 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"); +} + +static inline void platform_do_lowpower(unsigned int cpu, int *spurious) +{ + u32 mpidr = cpu_logical_map(cpu); + u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); + + for (;;) { + + /* Turn the CPU off on next WFI instruction. */ + exynos_cpu_power_down(core_id); + + wfi(); + + if (pen_release == core_id) { + /* + * OK, proper wakeup, we're done + */ + break; + } + + /* + * Getting here, means that we have come out of WFI without + * having been woken up - this shouldn't happen + * + * Just note it happening - when we're woken, we can report + * its occurrence. + */ + (*spurious)++; + } +} +#endif /* CONFIG_HOTPLUG_CPU */ + /** * exynos_core_power_down : power down the specified cpu * @cpu : the cpu to power down @@ -318,6 +367,31 @@ static void __init exynos_smp_prepare_cpus(unsigned int max_cpus) } } +#ifdef CONFIG_HOTPLUG_CPU +/* + * platform-specific code to shutdown a CPU + * + * Called with IRQs disabled + */ +static void __ref exynos_cpu_die(unsigned int cpu) +{ + int spurious = 0; + + v7_exit_coherency_flush(louis); + + platform_do_lowpower(cpu, &spurious); + + /* + * bring this CPU back into the world of cache + * coherency, and then restore interrupts + */ + cpu_leave_lowpower(); + + if (spurious) + pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); +} +#endif /* CONFIG_HOTPLUG_CPU */ + struct smp_operations exynos_smp_ops __initdata = { .smp_init_cpus = exynos_smp_init_cpus, .smp_prepare_cpus = exynos_smp_prepare_cpus,