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authorSudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>2012-09-25 18:40:12 +0100
committerAndrey Konovalov <andrey.konovalov@linaro.org>2013-05-25 13:20:32 +0400
commitb52a4b4ba21d5d27ac49a2ff2f40f621b23db8f9 (patch)
treeea8a8fd03a1466ac5e924c13c5345c1847cc8dbf
parent1efa105667d725678f4fe0dc389012d4a79d226b (diff)
downloadvexpress-lsk-b52a4b4ba21d5d27ac49a2ff2f40f621b23db8f9.tar.gz
ARM: perf: save/restore pmu registers in pm notifier
This adds core support for saving and restoring CPU PMU registers for suspend/resume support i.e. deeper C-states in cpuidle terms. This patch adds support only to ARMv7 PMU registers save/restore. It needs to be extended to xscale and ARMv6 if needed. Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
-rw-r--r--arch/arm/include/asm/pmu.h11
-rw-r--r--arch/arm/kernel/perf_event_cpu.c36
-rw-r--r--arch/arm/kernel/perf_event_v7.c47
3 files changed, 93 insertions, 1 deletions
diff --git a/arch/arm/include/asm/pmu.h b/arch/arm/include/asm/pmu.h
index 3713e57a467..0cd7824ca76 100644
--- a/arch/arm/include/asm/pmu.h
+++ b/arch/arm/include/asm/pmu.h
@@ -62,6 +62,15 @@ struct pmu_hw_events {
raw_spinlock_t pmu_lock;
};
+struct cpupmu_regs {
+ u32 pmc;
+ u32 pmcntenset;
+ u32 pmuseren;
+ u32 pmintenset;
+ u32 pmxevttype[8];
+ u32 pmxevtcnt[8];
+};
+
struct arm_pmu {
struct pmu pmu;
cpumask_t active_irqs;
@@ -82,6 +91,8 @@ struct arm_pmu {
int (*request_irq)(struct arm_pmu *, irq_handler_t handler);
void (*free_irq)(struct arm_pmu *);
int (*map_event)(struct perf_event *event);
+ void (*save_regs)(struct arm_pmu *, struct cpupmu_regs *);
+ void (*restore_regs)(struct arm_pmu *, struct cpupmu_regs *);
int num_events;
atomic_t active_events;
struct mutex reserve_mutex;
diff --git a/arch/arm/kernel/perf_event_cpu.c b/arch/arm/kernel/perf_event_cpu.c
index 4b338b3bdac..0b48a38e3cf 100644
--- a/arch/arm/kernel/perf_event_cpu.c
+++ b/arch/arm/kernel/perf_event_cpu.c
@@ -19,6 +19,7 @@
#define pr_fmt(fmt) "CPU PMU: " fmt
#include <linux/bitmap.h>
+#include <linux/cpu_pm.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/of.h>
@@ -37,6 +38,8 @@ static DEFINE_PER_CPU(struct perf_event * [ARMPMU_MAX_HWEVENTS], hw_events);
static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)], used_mask);
static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
+static DEFINE_PER_CPU(struct cpupmu_regs, cpu_pmu_regs);
+
/*
* Despite the names, these two functions are CPU-specific and are used
* by the OProfile/perf code.
@@ -178,10 +181,33 @@ static int __cpuinit cpu_pmu_notify(struct notifier_block *b,
return NOTIFY_OK;
}
+static int cpu_pmu_pm_notify(struct notifier_block *b,
+ unsigned long action, void *hcpu)
+{
+ int cpu = smp_processor_id();
+ struct arm_pmu *pmu = per_cpu(cpu_pmu, cpu);
+ struct cpupmu_regs *pmuregs = &per_cpu(cpu_pmu_regs, cpu);
+
+ if (!pmu)
+ return NOTIFY_DONE;
+
+ if (action == CPU_PM_ENTER && pmu->save_regs) {
+ pmu->save_regs(pmu, pmuregs);
+ } else if (action == CPU_PM_EXIT && pmu->restore_regs) {
+ pmu->restore_regs(pmu, pmuregs);
+ }
+
+ return NOTIFY_OK;
+}
+
static struct notifier_block __cpuinitdata cpu_pmu_hotplug_notifier = {
.notifier_call = cpu_pmu_notify,
};
+static struct notifier_block __cpuinitdata cpu_pmu_pm_notifier = {
+ .notifier_call = cpu_pmu_pm_notify,
+};
+
/*
* PMU platform driver and devicetree bindings.
*/
@@ -340,9 +366,17 @@ static int __init register_pmu_driver(void)
if (err)
return err;
+ err = cpu_pm_register_notifier(&cpu_pmu_pm_notifier);
+ if (err) {
+ unregister_cpu_notifier(&cpu_pmu_hotplug_notifier);
+ return err;
+ }
+
err = platform_driver_register(&cpu_pmu_driver);
- if (err)
+ if (err) {
+ cpu_pm_unregister_notifier(&cpu_pmu_pm_notifier);
unregister_cpu_notifier(&cpu_pmu_hotplug_notifier);
+ }
return err;
}
diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c
index 039cffb053a..dd1ad0ec29e 100644
--- a/arch/arm/kernel/perf_event_v7.c
+++ b/arch/arm/kernel/perf_event_v7.c
@@ -950,6 +950,51 @@ static void armv7_pmnc_dump_regs(struct arm_pmu *cpu_pmu)
}
#endif
+static void armv7pmu_save_regs(struct arm_pmu *cpu_pmu,
+ struct cpupmu_regs *regs)
+{
+ unsigned int cnt;
+ asm volatile("mrc p15, 0, %0, c9, c12, 0" : "=r" (regs->pmc));
+ if (!(regs->pmc & ARMV7_PMNC_E))
+ return;
+
+ asm volatile("mrc p15, 0, %0, c9, c12, 1" : "=r" (regs->pmcntenset));
+ asm volatile("mrc p15, 0, %0, c9, c14, 0" : "=r" (regs->pmuseren));
+ asm volatile("mrc p15, 0, %0, c9, c14, 1" : "=r" (regs->pmintenset));
+ asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (regs->pmxevtcnt[0]));
+ for (cnt = ARMV7_IDX_COUNTER0;
+ cnt <= ARMV7_IDX_COUNTER_LAST(cpu_pmu); cnt++) {
+ armv7_pmnc_select_counter(cnt);
+ asm volatile("mrc p15, 0, %0, c9, c13, 1"
+ : "=r"(regs->pmxevttype[cnt]));
+ asm volatile("mrc p15, 0, %0, c9, c13, 2"
+ : "=r"(regs->pmxevtcnt[cnt]));
+ }
+ return;
+}
+
+static void armv7pmu_restore_regs(struct arm_pmu *cpu_pmu,
+ struct cpupmu_regs *regs)
+{
+ unsigned int cnt;
+ if (!(regs->pmc & ARMV7_PMNC_E))
+ return;
+
+ asm volatile("mcr p15, 0, %0, c9, c12, 1" : : "r" (regs->pmcntenset));
+ asm volatile("mcr p15, 0, %0, c9, c14, 0" : : "r" (regs->pmuseren));
+ asm volatile("mcr p15, 0, %0, c9, c14, 1" : : "r" (regs->pmintenset));
+ asm volatile("mcr p15, 0, %0, c9, c13, 0" : : "r" (regs->pmxevtcnt[0]));
+ for (cnt = ARMV7_IDX_COUNTER0;
+ cnt <= ARMV7_IDX_COUNTER_LAST(cpu_pmu); cnt++) {
+ armv7_pmnc_select_counter(cnt);
+ asm volatile("mcr p15, 0, %0, c9, c13, 1"
+ : : "r"(regs->pmxevttype[cnt]));
+ asm volatile("mcr p15, 0, %0, c9, c13, 2"
+ : : "r"(regs->pmxevtcnt[cnt]));
+ }
+ asm volatile("mcr p15, 0, %0, c9, c12, 0" : : "r" (regs->pmc));
+}
+
static void armv7pmu_enable_event(struct perf_event *event)
{
unsigned long flags;
@@ -1223,6 +1268,8 @@ static void armv7pmu_init(struct arm_pmu *cpu_pmu)
cpu_pmu->start = armv7pmu_start;
cpu_pmu->stop = armv7pmu_stop;
cpu_pmu->reset = armv7pmu_reset;
+ cpu_pmu->save_regs = armv7pmu_save_regs;
+ cpu_pmu->restore_regs = armv7pmu_restore_regs;
cpu_pmu->max_period = (1LLU << 32) - 1;
};