diff options
Diffstat (limited to 'arch/arm/mach-exynos/platsmp.c')
| -rw-r--r-- | arch/arm/mach-exynos/platsmp.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c index 41ae28d69e6f..7a1ebfeeeeb8 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 +34,88 @@ extern void exynos4_secondary_startup(void); +/* + * Set or clear the USE_DELAYED_RESET_ASSERTION option, set on Exynos4 SoCs + * during hot-(un)plugging CPUx. + * + * The feature can be cleared safely during first boot of secondary CPU. + * + * Exynos4 SoCs require setting USE_DELAYED_RESET_ASSERTION during powering + * down a CPU so the CPU idle clock down feature could properly detect global + * idle state when CPUx is off. + */ +static void exynos_set_delayed_reset_assertion(u32 core_id, bool enable) +{ + if (soc_is_exynos4()) { + unsigned int tmp; + + tmp = pmu_raw_readl(EXYNOS_ARM_CORE_OPTION(core_id)); + if (enable) + tmp |= S5P_USE_DELAYED_RESET_ASSERTION; + else + tmp &= ~(S5P_USE_DELAYED_RESET_ASSERTION); + pmu_raw_writel(tmp, EXYNOS_ARM_CORE_OPTION(core_id)); + } +} + +#ifdef CONFIG_HOTPLUG_CPU +static inline void cpu_leave_lowpower(u32 core_id) +{ + 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"); + + exynos_set_delayed_reset_assertion(core_id, false); +} + +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); + + /* + * Exynos4 SoCs require setting + * USE_DELAYED_RESET_ASSERTION so the CPU idle + * clock down feature could properly detect + * global idle state when CPUx is off. + */ + exynos_set_delayed_reset_assertion(core_id, true); + + 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 @@ -43,6 +126,18 @@ extern void exynos4_secondary_startup(void); */ void exynos_cpu_power_down(int cpu) { + if (cpu == 0 && (of_machine_is_compatible("samsung,exynos5420") || + of_machine_is_compatible("samsung,exynos5800"))) { + /* + * Bypass power down for CPU0 during suspend. Check for + * the SYS_PWR_REG value to decide if we are suspending + * the system. + */ + int val = pmu_raw_readl(EXYNOS5_ARM_CORE0_SYS_PWR_REG); + + if (!(val & S5P_CORE_LOCAL_PWR_EN)) + return; + } pmu_raw_writel(0, EXYNOS_ARM_CORE_CONFIGURATION(cpu)); } @@ -121,6 +216,26 @@ static inline void __iomem *cpu_boot_reg(int cpu) } /* + * Set wake up by local power mode and execute software reset for given core. + * + * Currently this is needed only when booting secondary CPU on Exynos3250. + */ +static void exynos_core_restart(u32 core_id) +{ + u32 val; + + if (!of_machine_is_compatible("samsung,exynos3250")) + return; + + val = pmu_raw_readl(EXYNOS_ARM_CORE_STATUS(core_id)); + val |= S5P_CORE_WAKEUP_FROM_LOCAL_CFG; + pmu_raw_writel(val, EXYNOS_ARM_CORE_STATUS(core_id)); + + pr_info("CPU%u: Software reset\n", core_id); + pmu_raw_writel(EXYNOS_CORE_PO_RESET(core_id), EXYNOS_SWRESET); +} + +/* * Write pen_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. @@ -196,6 +311,9 @@ static int exynos_boot_secondary(unsigned int cpu, struct task_struct *idle) return -ETIMEDOUT; } } + + exynos_core_restart(core_id); + /* * Send the secondary CPU a soft interrupt, thereby causing * the boot monitor to read the system wide flags register, @@ -237,6 +355,9 @@ static int exynos_boot_secondary(unsigned int cpu, struct task_struct *idle) udelay(10); } + /* No harm if this is called during first boot of secondary CPU */ + exynos_set_delayed_reset_assertion(core_id, false); + /* * now the secondary core is starting up let it run its * calibrations, then wait for it to finish @@ -318,6 +439,33 @@ 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 exynos_cpu_die(unsigned int cpu) +{ + int spurious = 0; + u32 mpidr = cpu_logical_map(cpu); + u32 core_id = MPIDR_AFFINITY_LEVEL(mpidr, 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(core_id); + + 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, |