[PATCH v5 1/3] ARM: EXYNOS: Move code from hotplug.c to platsmp.c
Daniel Lezcano
daniel.lezcano at linaro.org
Tue Aug 5 07:46:10 PDT 2014
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 at samsung.com>
> Reviewed-by: Tomasz Figa <t.figa at 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,
>
--
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