From mboxrd@z Thu Jan 1 00:00:00 1970 From: jun.nie@linaro.org (Jun Nie) Date: Sat, 14 Mar 2015 19:49:41 +0800 Subject: [PATCH 06/10] ARM: zx: add cpu hotplug support In-Reply-To: <1426333785-3952-1-git-send-email-jun.nie@linaro.org> References: <1426333785-3952-1-git-send-email-jun.nie@linaro.org> Message-ID: <1426333785-3952-7-git-send-email-jun.nie@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org It's a clone of vexpress cpu hotplug implementation. Signed-off-by: Shawn Guo Signed-off-by: Jun Nie --- arch/arm/mach-zx/Makefile | 1 + arch/arm/mach-zx/core.h | 1 + arch/arm/mach-zx/hotplug.c | 108 +++++++++++++++++++++++++++++++++++++++++++++ arch/arm/mach-zx/platsmp.c | 3 ++ 4 files changed, 113 insertions(+) create mode 100644 arch/arm/mach-zx/hotplug.c diff --git a/arch/arm/mach-zx/Makefile b/arch/arm/mach-zx/Makefile index 7c2edf6..a3b386e7 100644 --- a/arch/arm/mach-zx/Makefile +++ b/arch/arm/mach-zx/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_SOC_ZX296702) += zx296702.o obj-$(CONFIG_SMP) += headsmp.o platsmp.o +obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o diff --git a/arch/arm/mach-zx/core.h b/arch/arm/mach-zx/core.h index 400c7b4..9f6b719 100644 --- a/arch/arm/mach-zx/core.h +++ b/arch/arm/mach-zx/core.h @@ -13,5 +13,6 @@ extern struct smp_operations zx_smp_ops; void zx_secondary_startup(void); +void zx_cpu_die(unsigned int cpu); #endif /* __MACH_ZX_CORE_H */ diff --git a/arch/arm/mach-zx/hotplug.c b/arch/arm/mach-zx/hotplug.c new file mode 100644 index 0000000..1b660e1 --- /dev/null +++ b/arch/arm/mach-zx/hotplug.c @@ -0,0 +1,108 @@ +/* + * Copyright 2014 Linaro Ltd. + * Copyright (C) 2014 ZTE Corporation. + * + * 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 +#include +#include + +#include +#include + +static inline void cpu_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"); +} + +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) +{ + /* + * there is no power-control hardware on this platform, so all + * we can do is put the core into WFI; this is safe as the calling + * code will have already disabled interrupts + */ + for (;;) { + wfi(); + + if (pen_release == cpu_logical_map(cpu)) { + /* + * 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 zx_cpu_die(unsigned int cpu) +{ + int spurious = 0; + + /* + * we're ready for shutdown now, so do it + */ + cpu_enter_lowpower(); + 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-zx/platsmp.c b/arch/arm/mach-zx/platsmp.c index e508a9c..ca157c3 100644 --- a/arch/arm/mach-zx/platsmp.c +++ b/arch/arm/mach-zx/platsmp.c @@ -144,4 +144,7 @@ struct smp_operations zx_smp_ops __initdata = { .smp_prepare_cpus = zx_smp_prepare_cpus, .smp_secondary_init = zx_secondary_init, .smp_boot_secondary = zx_boot_secondary, +#ifdef CONFIG_HOTPLUG_CPU + .cpu_die = zx_cpu_die, +#endif }; -- 1.9.1