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authorKukjin Kim <kgene.kim@samsung.com>2014-11-21 15:40:23 +0300
committerKukjin Kim <kgene.kim@samsung.com>2014-11-21 15:40:23 +0300
commit68847edc835e582dacbc90ded0c51d27b2ee2bf7 (patch)
tree82cc53aca70ce426098564b463f9644f152876b7 /arch/arm/mach-exynos/platsmp.c
parent03c1b7609fbb367c7a9ae49bd41e72cad38fe305 (diff)
parent13cfa6c4f7facfc690ba9e99ec382c151fddaced (diff)
downloadlinux-68847edc835e582dacbc90ded0c51d27b2ee2bf7.tar.xz
Merge branch 'v3.19-next/cleanup-samsung' into v3.19-next/mach-exynos
Diffstat (limited to 'arch/arm/mach-exynos/platsmp.c')
-rw-r--r--arch/arm/mach-exynos/platsmp.c113
1 files changed, 113 insertions, 0 deletions
diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
index 8543064dc445..adb36a8e8785 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
@@ -260,6 +343,9 @@ 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
@@ -341,6 +427,33 @@ 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,