From 33419a69a56436dda8e9187cf09ff0bde74d8a01 Mon Sep 17 00:00:00 2001 From: Bastian Hecht Date: Wed, 9 Jan 2013 19:41:51 +0000 Subject: ARM: SH-Mobile: sh73a0: Secondary CPUs handle own SCU flags When booting secondary CPUs we have used the main CPU to set up the Snoop Control Unit flags of these CPUs. It is a cleaner approach if every CPU takes care of its own flags. We avoid the need for locking and the program logic is more concise. With this patch the file headsmp-sh73a0.S is added that contains a startup vector for secondary CPUs that sets up its own SCU flags. Further in sh73a0_smp_prepare_cpus() we can rely on the generic ARM helper scu_power_mode(). This is possible as we don't cross borders anymore (every CPU handles its own flags) and need no locking. So we can throw out the needless function modify_scu_cpu_psr(). Signed-off-by: Bastian Hecht Signed-off-by: Simon Horman --- arch/arm/mach-shmobile/smp-sh73a0.c | 30 ++++-------------------------- 1 file changed, 4 insertions(+), 26 deletions(-) (limited to 'arch/arm/mach-shmobile/smp-sh73a0.c') diff --git a/arch/arm/mach-shmobile/smp-sh73a0.c b/arch/arm/mach-shmobile/smp-sh73a0.c index 5c5bcb59535..430b44ea85f 100644 --- a/arch/arm/mach-shmobile/smp-sh73a0.c +++ b/arch/arm/mach-shmobile/smp-sh73a0.c @@ -41,9 +41,6 @@ static void __iomem *scu_base_addr(void) return (void __iomem *)0xf0000000; } -static DEFINE_SPINLOCK(scu_lock); -static unsigned long tmp; - #ifdef CONFIG_HAVE_ARM_TWD static DEFINE_TWD_LOCAL_TIMER(twd_local_timer, 0xf0000600, 29); void __init sh73a0_register_twd(void) @@ -52,20 +49,6 @@ void __init sh73a0_register_twd(void) } #endif -static void modify_scu_cpu_psr(unsigned long set, unsigned long clr) -{ - void __iomem *scu_base = scu_base_addr(); - - spin_lock(&scu_lock); - tmp = __raw_readl(scu_base + 8); - tmp &= ~clr; - tmp |= set; - spin_unlock(&scu_lock); - - /* disable cache coherency after releasing the lock */ - __raw_writel(tmp, scu_base + 8); -} - static unsigned int __init sh73a0_get_core_count(void) { void __iomem *scu_base = scu_base_addr(); @@ -82,9 +65,6 @@ static int __cpuinit sh73a0_boot_secondary(unsigned int cpu, struct task_struct { cpu = cpu_logical_map(cpu); - /* enable cache coherency */ - modify_scu_cpu_psr(0, 3 << (cpu * 8)); - if (((__raw_readl(PSTR) >> (4 * cpu)) & 3) == 3) __raw_writel(1 << cpu, WUPCR); /* wake up */ else @@ -95,16 +75,14 @@ static int __cpuinit sh73a0_boot_secondary(unsigned int cpu, struct task_struct static void __init sh73a0_smp_prepare_cpus(unsigned int max_cpus) { - int cpu = cpu_logical_map(0); - scu_enable(scu_base_addr()); - /* Map the reset vector (in headsmp.S) */ + /* Map the reset vector (in headsmp-sh73a0.S) */ __raw_writel(0, APARMBAREA); /* 4k */ - __raw_writel(__pa(shmobile_secondary_vector), SBAR); + __raw_writel(__pa(sh73a0_secondary_vector), SBAR); - /* enable cache coherency on CPU0 */ - modify_scu_cpu_psr(0, 3 << (cpu * 8)); + /* enable cache coherency on booting CPU */ + scu_power_mode(scu_base_addr(), SCU_PM_NORMAL); } static void __init sh73a0_smp_init_cpus(void) -- cgit v1.2.3-70-g09d2 From 20aa11358d52e1a3fc037d601ffe704e6f55c5fb Mon Sep 17 00:00:00 2001 From: Bastian Hecht Date: Wed, 9 Jan 2013 19:41:52 +0000 Subject: ARM: SH-Mobile: sh73a0: Add CPU Hotplug Add the capability to add and remove CPUs on the fly. The Cortex-A9 offers the possibility to take single cores out of the MP Core. We add this capabilty taking care that caches are kept coherent. For verifying the shutdown we rely on the internal SH73A0 Power Status Register PSTR. Signed-off-by: Bastian Hecht Signed-off-by: Simon Horman --- arch/arm/mach-shmobile/smp-sh73a0.c | 36 ++++++++++++++++++++++++++++++------ 1 file changed, 30 insertions(+), 6 deletions(-) (limited to 'arch/arm/mach-shmobile/smp-sh73a0.c') diff --git a/arch/arm/mach-shmobile/smp-sh73a0.c b/arch/arm/mach-shmobile/smp-sh73a0.c index 430b44ea85f..9812ea3255c 100644 --- a/arch/arm/mach-shmobile/smp-sh73a0.c +++ b/arch/arm/mach-shmobile/smp-sh73a0.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -36,6 +37,8 @@ #define SBAR IOMEM(0xe6180020) #define APARMBAREA IOMEM(0xe6f10020) +#define PSTR_SHUTDOWN_MODE 3 + static void __iomem *scu_base_addr(void) { return (void __iomem *)0xf0000000; @@ -92,16 +95,20 @@ static void __init sh73a0_smp_init_cpus(void) shmobile_smp_init_cpus(ncores); } -static int __maybe_unused sh73a0_cpu_kill(unsigned int cpu) +#ifdef CONFIG_HOTPLUG_CPU +static int sh73a0_cpu_kill(unsigned int cpu) { + int k; + u32 pstr; - /* this function is running on another CPU than the offline target, - * here we need wait for shutdown code in platform_cpu_die() to - * finish before asking SoC-specific code to power off the CPU core. + /* + * wait until the power status register confirms the shutdown of the + * offline target */ for (k = 0; k < 1000; k++) { - if (shmobile_cpu_is_dead(cpu)) + pstr = (__raw_readl(PSTR) >> (4 * cpu)) & 3; + if (pstr == PSTR_SHUTDOWN_MODE) return 1; mdelay(1); @@ -110,6 +117,23 @@ static int __maybe_unused sh73a0_cpu_kill(unsigned int cpu) return 0; } +static void sh73a0_cpu_die(unsigned int cpu) +{ + /* + * The ARM MPcore does not issue a cache coherency request for the L1 + * cache when powering off single CPUs. We must take care of this and + * further caches. + */ + dsb(); + flush_cache_all(); + + /* Set power off mode. This takes the CPU out of the MP cluster */ + scu_power_mode(scu_base_addr(), SCU_PM_POWEROFF); + + /* Enter shutdown mode */ + cpu_do_idle(); +} +#endif /* CONFIG_HOTPLUG_CPU */ struct smp_operations sh73a0_smp_ops __initdata = { .smp_init_cpus = sh73a0_smp_init_cpus, @@ -118,7 +142,7 @@ struct smp_operations sh73a0_smp_ops __initdata = { .smp_boot_secondary = sh73a0_boot_secondary, #ifdef CONFIG_HOTPLUG_CPU .cpu_kill = sh73a0_cpu_kill, - .cpu_die = shmobile_cpu_die, + .cpu_die = sh73a0_cpu_die, .cpu_disable = shmobile_cpu_disable, #endif }; -- cgit v1.2.3-70-g09d2 From dc784e73b45dc055f9dcb174ea5753ea020516fc Mon Sep 17 00:00:00 2001 From: Ulrich Hecht Date: Thu, 10 Jan 2013 11:16:44 +0100 Subject: ARM: mach-shmobile: sh73a0: allow unplugging of CPU0 sh73a0 deals fine with disabling any core, so we should permit it. Signed-off-by: Ulrich Hecht Signed-off-by: Simon Horman --- arch/arm/mach-shmobile/smp-sh73a0.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/mach-shmobile/smp-sh73a0.c') diff --git a/arch/arm/mach-shmobile/smp-sh73a0.c b/arch/arm/mach-shmobile/smp-sh73a0.c index 9812ea3255c..acb46a94ccd 100644 --- a/arch/arm/mach-shmobile/smp-sh73a0.c +++ b/arch/arm/mach-shmobile/smp-sh73a0.c @@ -143,6 +143,6 @@ struct smp_operations sh73a0_smp_ops __initdata = { #ifdef CONFIG_HOTPLUG_CPU .cpu_kill = sh73a0_cpu_kill, .cpu_die = sh73a0_cpu_die, - .cpu_disable = shmobile_cpu_disable, + .cpu_disable = shmobile_cpu_disable_any, #endif }; -- cgit v1.2.3-70-g09d2