diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c index 1c73694c871a..10e070368f64 100644 --- a/arch/arm/mach-omap2/omap-smp.c +++ b/arch/arm/mach-omap2/omap-smp.c @@ -69,8 +69,6 @@ static const struct omap_smp_config omap5_cfg __initconst = { .startup_addr = omap5_secondary_startup, }; -static DEFINE_SPINLOCK(boot_lock); - void __iomem *omap4_get_scu_base(void) { return cfg.scu_base; @@ -173,12 +171,6 @@ static void omap4_secondary_init(unsigned int cpu) /* Enable ACR to allow for ICUALLU workaround */ omap5_secondary_harden_predictor(); } - - /* - * Synchronise with the boot thread. - */ - spin_lock(&boot_lock); - spin_unlock(&boot_lock); } static int omap4_boot_secondary(unsigned int cpu, struct task_struct *idle) @@ -187,12 +179,6 @@ static int omap4_boot_secondary(unsigned int cpu, struct task_struct *idle) static bool booted; static struct powerdomain *cpu1_pwrdm; - /* - * Set synchronisation state between this boot processor - * and the secondary one - */ - spin_lock(&boot_lock); - /* * Update the AuxCoreBoot0 with boot state for secondary core. * omap4_secondary_startup() routine will hold the secondary core till @@ -266,12 +252,6 @@ static int omap4_boot_secondary(unsigned int cpu, struct task_struct *idle) arch_send_wakeup_ipi_mask(cpumask_of(cpu)); - /* - * Now the secondary core is starting up let it run its - * calibrations, then wait for it to finish - */ - spin_unlock(&boot_lock); - return 0; } diff --git a/arch/arm/mach-realview/Makefile b/arch/arm/mach-realview/Makefile index adf39ad71cc3..6ca6400fa51e 100644 --- a/arch/arm/mach-realview/Makefile +++ b/arch/arm/mach-realview/Makefile @@ -5,4 +5,3 @@ ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/arch/arm/plat-versatile/inc obj-y += realview-dt.o obj-$(CONFIG_SMP) += platsmp-dt.o -obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o diff --git a/arch/arm/mach-realview/hotplug.c b/arch/arm/mach-realview/hotplug.c deleted file mode 100644 index 968e2d1964f6..000000000000 --- a/arch/arm/mach-realview/hotplug.c +++ /dev/null @@ -1,111 +0,0 @@ -/* - * 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 -#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, #0x20\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) - : "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, #0x20\n" - " mcr p15, 0, %0, c1, c0, 1\n" - : "=&r" (v) - : "Ir" (CR_C) - : "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 (;;) { - /* - * here's the WFI - */ - asm(".word 0xe320f003\n" - : - : - : "memory", "cc"); - - 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 realview_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-realview/hotplug.h b/arch/arm/mach-realview/hotplug.h deleted file mode 100644 index eacd7a4dad2f..000000000000 --- a/arch/arm/mach-realview/hotplug.h +++ /dev/null @@ -1 +0,0 @@ -void realview_cpu_die(unsigned int cpu); diff --git a/arch/arm/mach-realview/platsmp-dt.c b/arch/arm/mach-realview/platsmp-dt.c index c242423bf8db..ce331b3dbf54 100644 --- a/arch/arm/mach-realview/platsmp-dt.c +++ b/arch/arm/mach-realview/platsmp-dt.c @@ -17,7 +17,6 @@ #include #include -#include "hotplug.h" #define REALVIEW_SYS_FLAGSSET_OFFSET 0x30 @@ -79,6 +78,13 @@ static void __init realview_smp_prepare_cpus(unsigned int max_cpus) __pa_symbol(versatile_secondary_startup)); } +#ifdef CONFIG_HOTPLUG_CPU +static void realview_cpu_die(unsigned int cpu) +{ + return versatile_immitation_cpu_die(cpu, 0x20); +} +#endif + static const struct smp_operations realview_dt_smp_ops __initconst = { .smp_prepare_cpus = realview_smp_prepare_cpus, .smp_secondary_init = versatile_secondary_init, diff --git a/arch/arm/mach-vexpress/Makefile b/arch/arm/mach-vexpress/Makefile index 51c35e2b737a..3651a1ed0f2b 100644 --- a/arch/arm/mach-vexpress/Makefile +++ b/arch/arm/mach-vexpress/Makefile @@ -15,6 +15,5 @@ obj-$(CONFIG_ARCH_VEXPRESS_TC2_PM) += tc2_pm.o CFLAGS_tc2_pm.o += -march=armv7-a CFLAGS_REMOVE_tc2_pm.o = -pg obj-$(CONFIG_SMP) += platsmp.o -obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o obj-$(CONFIG_ARCH_MPS2) += v2m-mps2.o diff --git a/arch/arm/mach-vexpress/core.h b/arch/arm/mach-vexpress/core.h index a162ab46ee02..f4a7519084f1 100644 --- a/arch/arm/mach-vexpress/core.h +++ b/arch/arm/mach-vexpress/core.h @@ -1,5 +1,3 @@ bool vexpress_smp_init_ops(void); extern const struct smp_operations vexpress_smp_dt_ops; - -extern void vexpress_cpu_die(unsigned int cpu); diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c index 742499bac6d0..af0113be5970 100644 --- a/arch/arm/mach-vexpress/platsmp.c +++ b/arch/arm/mach-vexpress/platsmp.c @@ -82,6 +82,13 @@ static void __init vexpress_smp_dt_prepare_cpus(unsigned int max_cpus) vexpress_flags_set(__pa_symbol(versatile_secondary_startup)); } +#ifdef CONFIG_HOTPLUG_CPU +static void vexpress_cpu_die(unsigned int cpu) +{ + versatile_immitation_cpu_die(cpu, 0x40); +} +#endif + const struct smp_operations vexpress_smp_dt_ops __initconst = { .smp_prepare_cpus = vexpress_smp_dt_prepare_cpus, .smp_secondary_init = versatile_secondary_init, diff --git a/arch/arm/plat-versatile/Makefile b/arch/arm/plat-versatile/Makefile index bff3ba889882..b2f0ddfdc4cc 100644 --- a/arch/arm/plat-versatile/Makefile +++ b/arch/arm/plat-versatile/Makefile @@ -2,3 +2,4 @@ ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include obj-$(CONFIG_PLAT_VERSATILE_SCHED_CLOCK) += sched-clock.o obj-$(CONFIG_SMP) += headsmp.o platsmp.o +obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o diff --git a/arch/arm/plat-versatile/headsmp.S b/arch/arm/plat-versatile/headsmp.S index 40f27e52de75..e99396dfa6f3 100644 --- a/arch/arm/plat-versatile/headsmp.S +++ b/arch/arm/plat-versatile/headsmp.S @@ -37,5 +37,5 @@ pen: ldr r7, [r6] .align 1: .long . - .long pen_release + .long versatile_cpu_release ENDPROC(versatile_secondary_startup) diff --git a/arch/arm/mach-vexpress/hotplug.c b/arch/arm/plat-versatile/hotplug.c similarity index 56% rename from arch/arm/mach-vexpress/hotplug.c rename to arch/arm/plat-versatile/hotplug.c index d8f1a05f5e87..c974958417fe 100644 --- a/arch/arm/mach-vexpress/hotplug.c +++ b/arch/arm/plat-versatile/hotplug.c @@ -1,12 +1,15 @@ /* - * 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. + * + * This hotplug implementation is _specific_ to the situation found on + * ARM development platforms where there is _no_ possibility of actually + * taking a CPU offline, resetting it, or otherwise. Real platforms must + * NOT copy this code. */ #include #include @@ -15,9 +18,9 @@ #include #include -#include "core.h" +#include -static inline void cpu_enter_lowpower(void) +static inline void versatile_immitation_enter_lowpower(unsigned int actrl_mask) { unsigned int v; @@ -34,11 +37,11 @@ static inline void cpu_enter_lowpower(void) " bic %0, %0, %2\n" " mcr p15, 0, %0, c1, c0, 0\n" : "=&r" (v) - : "r" (0), "Ir" (CR_C), "Ir" (0x40) + : "r" (0), "Ir" (CR_C), "Ir" (actrl_mask) : "cc"); } -static inline void cpu_leave_lowpower(void) +static inline void versatile_immitation_leave_lowpower(unsigned int actrl_mask) { unsigned int v; @@ -50,21 +53,23 @@ static inline void cpu_leave_lowpower(void) " orr %0, %0, %2\n" " mcr p15, 0, %0, c1, c0, 1\n" : "=&r" (v) - : "Ir" (CR_C), "Ir" (0x40) + : "Ir" (CR_C), "Ir" (actrl_mask) : "cc"); } -static inline void platform_do_lowpower(unsigned int cpu, int *spurious) +static inline void versatile_immitation_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 + * code will have already disabled interrupts. + * + * This code should not be used outside Versatile platforms. */ for (;;) { wfi(); - if (pen_release == cpu_logical_map(cpu)) { + if (versatile_cpu_release == cpu_logical_map(cpu)) { /* * OK, proper wakeup, we're done */ @@ -83,25 +88,17 @@ static inline void platform_do_lowpower(unsigned int cpu, int *spurious) } /* - * platform-specific code to shutdown a CPU - * - * Called with IRQs disabled + * platform-specific code to shutdown a CPU. + * This code supports immitation-style CPU hotplug for Versatile/Realview/ + * Versatile Express platforms that are unable to do real CPU hotplug. */ -void vexpress_cpu_die(unsigned int cpu) +void versatile_immitation_cpu_die(unsigned int cpu, unsigned int actrl_mask) { 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(); + versatile_immitation_enter_lowpower(actrl_mask); + versatile_immitation_do_lowpower(cpu, &spurious); + versatile_immitation_leave_lowpower(actrl_mask); if (spurious) pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); diff --git a/arch/arm/plat-versatile/include/plat/platsmp.h b/arch/arm/plat-versatile/include/plat/platsmp.h index 50fb830192e0..1b087fbbc700 100644 --- a/arch/arm/plat-versatile/include/plat/platsmp.h +++ b/arch/arm/plat-versatile/include/plat/platsmp.h @@ -8,7 +8,9 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ +extern volatile int versatile_cpu_release; extern void versatile_secondary_startup(void); extern void versatile_secondary_init(unsigned int cpu); extern int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle); +void versatile_immitation_cpu_die(unsigned int cpu, unsigned int actrl_mask); diff --git a/arch/arm/plat-versatile/platsmp.c b/arch/arm/plat-versatile/platsmp.c index c2366510187a..6e2836243187 100644 --- a/arch/arm/plat-versatile/platsmp.c +++ b/arch/arm/plat-versatile/platsmp.c @@ -7,6 +7,11 @@ * 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. + * + * This code is specific to the hardware found on ARM Realview and + * Versatile Express platforms where the CPUs are unable to be individually + * woken, and where there is no way to hot-unplug CPUs. Real platforms + * should not copy this code. */ #include #include @@ -21,18 +26,32 @@ #include /* - * Write pen_release in a way that is guaranteed to be visible to all - * observers, irrespective of whether they're taking part in coherency + * versatile_cpu_release controls the release of CPUs from the holding + * pen in headsmp.S, which exists because we are not always able to + * control the release of individual CPUs from the board firmware. + * Production platforms do not need this. + */ +volatile int versatile_cpu_release = -1; + +/* + * Write versatile_cpu_release in a way that is guaranteed to be visible to + * all observers, irrespective of whether they're taking part in coherency * or not. This is necessary for the hotplug code to work reliably. */ -static void write_pen_release(int val) +static void versatile_write_cpu_release(int val) { - pen_release = val; + versatile_cpu_release = val; smp_wmb(); - sync_cache_w(&pen_release); + sync_cache_w(&versatile_cpu_release); } -static DEFINE_SPINLOCK(boot_lock); +/* + * versatile_lock exists to avoid running the loops_per_jiffy delay loop + * calibrations on the secondary CPU while the requesting CPU is using + * the limited-bandwidth bus - which affects the calibration value. + * Production platforms do not need this. + */ +static DEFINE_RAW_SPINLOCK(versatile_lock); void versatile_secondary_init(unsigned int cpu) { @@ -40,13 +59,13 @@ void versatile_secondary_init(unsigned int cpu) * let the primary processor know we're out of the * pen, then head off into the C entry point */ - write_pen_release(-1); + versatile_write_cpu_release(-1); /* * Synchronise with the boot thread. */ - spin_lock(&boot_lock); - spin_unlock(&boot_lock); + raw_spin_lock(&versatile_lock); + raw_spin_unlock(&versatile_lock); } int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle) @@ -57,7 +76,7 @@ int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle) * Set synchronisation state between this boot processor * and the secondary one */ - spin_lock(&boot_lock); + raw_spin_lock(&versatile_lock); /* * This is really belt and braces; we hold unintended secondary @@ -65,7 +84,7 @@ int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle) * since we haven't sent them a soft interrupt, they shouldn't * be there. */ - write_pen_release(cpu_logical_map(cpu)); + versatile_write_cpu_release(cpu_logical_map(cpu)); /* * Send the secondary CPU a soft interrupt, thereby causing @@ -77,7 +96,7 @@ int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle) timeout = jiffies + (1 * HZ); while (time_before(jiffies, timeout)) { smp_rmb(); - if (pen_release == -1) + if (versatile_cpu_release == -1) break; udelay(10); @@ -87,7 +106,7 @@ int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle) * now the secondary core is starting up let it run its * calibrations, then wait for it to finish */ - spin_unlock(&boot_lock); + raw_spin_unlock(&versatile_lock); - return pen_release != -1 ? -ENOSYS : 0; + return versatile_cpu_release != -1 ? -ENOSYS : 0; }