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authorKrzysztof Kozlowski <k.kozlowski@samsung.com>2014-09-13 21:49:31 +0400
committerKukjin Kim <kgene.kim@samsung.com>2014-10-20 19:06:22 +0400
commit6f0b7c0c6faa76c32891ef1f7ee37c7e10aeb039 (patch)
tree00712ee5ab9c84ed2c4f954d8004f7c2e1c8d833 /arch/arm/mach-exynos/platsmp.c
parentf114040e3ea6e07372334ade75d1ee0775c355e1 (diff)
downloadlinux-6f0b7c0c6faa76c32891ef1f7ee37c7e10aeb039.tar.xz
ARM: EXYNOS: Move code from hotplug.c to platsmp.c
Cleanup a little the SMP/hotplug code for Exynos by: 1. Moving completely all functions from hotplug.c into the platsmp.c; 2. Deleting the hotplug.c file. After recent cleanups (e.g. 75ad2ab28f0f "ARM: EXYNOS: use v7_exit_coherency_flush macro for cache disabling") there was only CPU power down related code in hotplug.c file. Rationale behind the code movement and benefits: 1. The file platsmp.c is the only user of code located in hotplug.c. Keeping code in hotplug.c required declaring exynos_cpu_die() in common.h. Such dependencies and mentioned exynos_cpu_die() declaration can be removed. 2. In next patches exynos_set_delayed_reset_assertion() will be introduced. This function will be called by: - cpu_leave_power (hotplug.c), - platform_do_lowpower (hotplug.c), - exynos_boot_secondary (platsmp.c). Merging hotplug.c into platsmp.c leads to simpler and cleaner code with less dependencies between files. The commit only moves code around with one additional observable change: the hotplug.c was compiled with custom CFLAGS (-march=armv7-a). These CFLAGS are not necessary any more. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Reviewed-by: Tomasz Figa <t.figa@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Diffstat (limited to 'arch/arm/mach-exynos/platsmp.c')
-rw-r--r--arch/arm/mach-exynos/platsmp.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/arch/arm/mach-exynos/platsmp.c b/arch/arm/mach-exynos/platsmp.c
index 41ae28d69e6f..87a73eec9b36 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 +34,54 @@
extern void exynos4_secondary_startup(void);
+#ifdef CONFIG_HOTPLUG_CPU
+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)
+{
+ 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);
+
+ 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
@@ -318,6 +367,31 @@ 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 __ref exynos_cpu_die(unsigned int cpu)
+{
+ int spurious = 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();
+
+ 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,