--- /dev/null
+/*
+ * Linux performance counter support for MIPS.
+ *
+ * Copyright (C) 2010 MIPS Technologies, Inc.
+ * Author: Deng-Cheng Zhu
+ *
+ * This code is based on the implementation for ARM, which is in turn
+ * based on the sparc64 perf event code and the x86 code. Performance
+ * counter access is based on the MIPS Oprofile code.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/cpumask.h>
+#include <linux/interrupt.h>
+#include <linux/smp.h>
+#include <linux/kernel.h>
+#include <linux/perf_event.h>
+#include <linux/uaccess.h>
+
+#include <asm/irq.h>
+#include <asm/irq_regs.h>
+#include <asm/stacktrace.h>
+#include <asm/time.h> /* For perf_irq */
+
+/* These are for 32bit counters. For 64bit ones, define them accordingly. */
+#define MAX_PERIOD ((1ULL << 32) - 1)
+#define VALID_COUNT 0x7fffffff
+#define TOTAL_BITS 32
+#define HIGHEST_BIT 31
+
+#define MIPS_MAX_HWEVENTS 4
+
+struct cpu_hw_events {
+ /* Array of events on this cpu. */
+ struct perf_event *events[MIPS_MAX_HWEVENTS];
+
+ /*
+ * Set the bit (indexed by the counter number) when the counter
+ * is used for an event.
+ */
+ unsigned long used_mask[BITS_TO_LONGS(MIPS_MAX_HWEVENTS)];
+
+ /*
+ * The borrowed MSB for the performance counter. A MIPS performance
+ * counter uses its bit 31 (for 32bit counters) or bit 63 (for 64bit
+ * counters) as a factor of determining whether a counter overflow
+ * should be signaled. So here we use a separate MSB for each
+ * counter to make things easy.
+ */
+ unsigned long msbs[BITS_TO_LONGS(MIPS_MAX_HWEVENTS)];
+
+ /*
+ * Software copy of the control register for each performance counter.
+ * MIPS CPUs vary in performance counters. They use this differently,
+ * and even may not use it.
+ */
+ unsigned int saved_ctrl[MIPS_MAX_HWEVENTS];
+};
+DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
+ .saved_ctrl = {0},
+};
+
+/* The description of MIPS performance events. */
+struct mips_perf_event {
+ unsigned int event_id;
+ /*
+ * MIPS performance counters are indexed starting from 0.
+ * CNTR_EVEN indicates the indexes of the counters to be used are
+ * even numbers.
+ */
+ unsigned int cntr_mask;
+ #define CNTR_EVEN 0x55555555
+ #define CNTR_ODD 0xaaaaaaaa
+#ifdef CONFIG_MIPS_MT_SMP
+ enum {
+ T = 0,
+ V = 1,
+ P = 2,
+ } range;
+#else
+ #define T
+ #define V
+ #define P
+#endif
+};
+
+#define UNSUPPORTED_PERF_EVENT_ID 0xffffffff
+#define C(x) PERF_COUNT_HW_CACHE_##x
+
+struct mips_pmu {
+ const char *name;
+ int irq;
+ irqreturn_t (*handle_irq)(int irq, void *dev);
+ int (*handle_shared_irq)(void);
+ void (*start)(void);
+ void (*stop)(void);
+ int (*alloc_counter)(struct cpu_hw_events *cpuc,
+ struct hw_perf_event *hwc);
+ u64 (*read_counter)(unsigned int idx);
+ void (*write_counter)(unsigned int idx, u64 val);
+ void (*enable_event)(struct hw_perf_event *evt, int idx);
+ void (*disable_event)(int idx);
+ const struct mips_perf_event (*general_event_map)[PERF_COUNT_HW_MAX];
+ const struct mips_perf_event (*cache_event_map)
+ [PERF_COUNT_HW_CACHE_MAX]
+ [PERF_COUNT_HW_CACHE_OP_MAX]
+ [PERF_COUNT_HW_CACHE_RESULT_MAX];
+ unsigned int num_counters;
+};
+
+static const struct mips_pmu *mipspmu;
+
+static int
+mipspmu_event_set_period(struct perf_event *event,
+ struct hw_perf_event *hwc,
+ int idx)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ s64 left = local64_read(&hwc->period_left);
+ s64 period = hwc->sample_period;
+ int ret = 0;
+ u64 uleft;
+ unsigned long flags;
+
+ if (unlikely(left <= -period)) {
+ left = period;
+ local64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ }
+
+ if (unlikely(left <= 0)) {
+ left += period;
+ local64_set(&hwc->period_left, left);
+ hwc->last_period = period;
+ ret = 1;
+ }
+
+ if (left > (s64)MAX_PERIOD)
+ left = MAX_PERIOD;
+
+ local64_set(&hwc->prev_count, (u64)-left);
+
+ local_irq_save(flags);
+ uleft = (u64)(-left) & MAX_PERIOD;
+ uleft > VALID_COUNT ?
+ set_bit(idx, cpuc->msbs) : clear_bit(idx, cpuc->msbs);
+ mipspmu->write_counter(idx, (u64)(-left) & VALID_COUNT);
+ local_irq_restore(flags);
+
+ perf_event_update_userpage(event);
+
+ return ret;
+}
+
+static int mipspmu_enable(struct perf_event *event)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx;
+ int err = 0;
+
+ /* To look for a free counter for this event. */
+ idx = mipspmu->alloc_counter(cpuc, hwc);
+ if (idx < 0) {
+ err = idx;
+ goto out;
+ }
+
+ /*
+ * If there is an event in the counter we are going to use then
+ * make sure it is disabled.
+ */
+ event->hw.idx = idx;
+ mipspmu->disable_event(idx);
+ cpuc->events[idx] = event;
+
+ /* Set the period for the event. */
+ mipspmu_event_set_period(event, hwc, idx);
+
+ /* Enable the event. */
+ mipspmu->enable_event(hwc, idx);
+
+ /* Propagate our changes to the userspace mapping. */
+ perf_event_update_userpage(event);
+
+out:
+ return err;
+}
+
+static void mipspmu_event_update(struct perf_event *event,
+ struct hw_perf_event *hwc,
+ int idx)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ unsigned long flags;
+ int shift = 64 - TOTAL_BITS;
+ s64 prev_raw_count, new_raw_count;
+ s64 delta;
+
+again:
+ prev_raw_count = local64_read(&hwc->prev_count);
+ local_irq_save(flags);
+ /* Make the counter value be a "real" one. */
+ new_raw_count = mipspmu->read_counter(idx);
+ if (new_raw_count & (test_bit(idx, cpuc->msbs) << HIGHEST_BIT)) {
+ new_raw_count &= VALID_COUNT;
+ clear_bit(idx, cpuc->msbs);
+ } else
+ new_raw_count |= (test_bit(idx, cpuc->msbs) << HIGHEST_BIT);
+ local_irq_restore(flags);
+
+ if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+ new_raw_count) != prev_raw_count)
+ goto again;
+
+ delta = (new_raw_count << shift) - (prev_raw_count << shift);
+ delta >>= shift;
+
+ local64_add(delta, &event->count);
+ local64_sub(delta, &hwc->period_left);
+
+ return;
+}
+
+static void mipspmu_disable(struct perf_event *event)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct hw_perf_event *hwc = &event->hw;
+ int idx = hwc->idx;
+
+
+ WARN_ON(idx < 0 || idx >= mipspmu->num_counters);
+
+ /* We are working on a local event. */
+ mipspmu->disable_event(idx);
+
+ barrier();
+
+ mipspmu_event_update(event, hwc, idx);
+ cpuc->events[idx] = NULL;
+ clear_bit(idx, cpuc->used_mask);
+
+ perf_event_update_userpage(event);
+}
+
+static void mipspmu_unthrottle(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ mipspmu->enable_event(hwc, hwc->idx);
+}
+
+static void mipspmu_read(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ /* Don't read disabled counters! */
+ if (hwc->idx < 0)
+ return;
+
+ mipspmu_event_update(event, hwc, hwc->idx);
+}
+
+static struct pmu pmu = {
+ .enable = mipspmu_enable,
+ .disable = mipspmu_disable,
+ .unthrottle = mipspmu_unthrottle,
+ .read = mipspmu_read,
+};
+
+static atomic_t active_events = ATOMIC_INIT(0);
+static DEFINE_MUTEX(pmu_reserve_mutex);
+static int (*save_perf_irq)(void);
+
+static int mipspmu_get_irq(void)
+{
+ int err;
+
+ if (mipspmu->irq >= 0) {
+ /* Request my own irq handler. */
+ err = request_irq(mipspmu->irq, mipspmu->handle_irq,
+ IRQF_DISABLED | IRQF_NOBALANCING,
+ "mips_perf_pmu", NULL);
+ if (err) {
+ pr_warning("Unable to request IRQ%d for MIPS "
+ "performance counters!\n", mipspmu->irq);
+ }
+ } else if (cp0_perfcount_irq < 0) {
+ /*
+ * We are sharing the irq number with the timer interrupt.
+ */
+ save_perf_irq = perf_irq;
+ perf_irq = mipspmu->handle_shared_irq;
+ err = 0;
+ } else {
+ pr_warning("The platform hasn't properly defined its "
+ "interrupt controller.\n");
+ err = -ENOENT;
+ }
+
+ return err;
+}
+
+static void mipspmu_free_irq(void)
+{
+ if (mipspmu->irq >= 0)
+ free_irq(mipspmu->irq, NULL);
+ else if (cp0_perfcount_irq < 0)
+ perf_irq = save_perf_irq;
+}
+
+static inline unsigned int
+mipspmu_perf_event_encode(const struct mips_perf_event *pev)
+{
+/*
+ * Top 8 bits for range, next 16 bits for cntr_mask, lowest 8 bits for
+ * event_id.
+ */
+#ifdef CONFIG_MIPS_MT_SMP
+ return ((unsigned int)pev->range << 24) |
+ (pev->cntr_mask & 0xffff00) |
+ (pev->event_id & 0xff);
+#else
+ return (pev->cntr_mask & 0xffff00) |
+ (pev->event_id & 0xff);
+#endif
+}
+
+static const struct mips_perf_event *
+mipspmu_map_general_event(int idx)
+{
+ const struct mips_perf_event *pev;
+
+ pev = ((*mipspmu->general_event_map)[idx].event_id ==
+ UNSUPPORTED_PERF_EVENT_ID ? ERR_PTR(-EOPNOTSUPP) :
+ &(*mipspmu->general_event_map)[idx]);
+
+ return pev;
+}
+
+static const struct mips_perf_event *
+mipspmu_map_cache_event(u64 config)
+{
+ unsigned int cache_type, cache_op, cache_result;
+ const struct mips_perf_event *pev;
+
+ cache_type = (config >> 0) & 0xff;
+ if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
+ return ERR_PTR(-EINVAL);
+
+ cache_op = (config >> 8) & 0xff;
+ if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
+ return ERR_PTR(-EINVAL);
+
+ cache_result = (config >> 16) & 0xff;
+ if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
+ return ERR_PTR(-EINVAL);
+
+ pev = &((*mipspmu->cache_event_map)
+ [cache_type]
+ [cache_op]
+ [cache_result]);
+
+ if (pev->event_id == UNSUPPORTED_PERF_EVENT_ID)
+ return ERR_PTR(-EOPNOTSUPP);
+
+ return pev;
+
+}
+
+static int validate_event(struct cpu_hw_events *cpuc,
+ struct perf_event *event)
+{
+ struct hw_perf_event fake_hwc = event->hw;
+
+ if (event->pmu && event->pmu != &pmu)
+ return 0;
+
+ return mipspmu->alloc_counter(cpuc, &fake_hwc) >= 0;
+}
+
+static int validate_group(struct perf_event *event)
+{
+ struct perf_event *sibling, *leader = event->group_leader;
+ struct cpu_hw_events fake_cpuc;
+
+ memset(&fake_cpuc, 0, sizeof(fake_cpuc));
+
+ if (!validate_event(&fake_cpuc, leader))
+ return -ENOSPC;
+
+ list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
+ if (!validate_event(&fake_cpuc, sibling))
+ return -ENOSPC;
+ }
+
+ if (!validate_event(&fake_cpuc, event))
+ return -ENOSPC;
+
+ return 0;
+}
+
+/*
+ * mipsxx/rm9000/loongson2 have different performance counters, they have
+ * specific low-level init routines.
+ */
+static int __hw_perf_event_init(struct perf_event *event);
+
+static void hw_perf_event_destroy(struct perf_event *event)
+{
+ if (atomic_dec_and_mutex_lock(&active_events,
+ &pmu_reserve_mutex)) {
+ /*
+ * We must not call the destroy function with interrupts
+ * disabled.
+ */
+ on_each_cpu(reset_counters,
+ (void *)(long)mipspmu->num_counters, 1);
+ mipspmu_free_irq();
+ mutex_unlock(&pmu_reserve_mutex);
+ }
+}
+
+const struct pmu *hw_perf_event_init(struct perf_event *event)
+{
+ int err = 0;
+
+ if (!mipspmu || event->cpu >= nr_cpumask_bits ||
+ (event->cpu >= 0 && !cpu_online(event->cpu)))
+ return ERR_PTR(-ENODEV);
+
+ if (!atomic_inc_not_zero(&active_events)) {
+ if (atomic_read(&active_events) > MIPS_MAX_HWEVENTS) {
+ atomic_dec(&active_events);
+ return ERR_PTR(-ENOSPC);
+ }
+
+ mutex_lock(&pmu_reserve_mutex);
+ if (atomic_read(&active_events) == 0)
+ err = mipspmu_get_irq();
+
+ if (!err)
+ atomic_inc(&active_events);
+ mutex_unlock(&pmu_reserve_mutex);
+ }
+
+ if (err)
+ return ERR_PTR(err);
+
+ err = __hw_perf_event_init(event);
+ if (err)
+ hw_perf_event_destroy(event);
+
+ return err ? ERR_PTR(err) : &pmu;
+}
+
+void hw_perf_enable(void)
+{
+ if (mipspmu)
+ mipspmu->start();
+}
+
+void hw_perf_disable(void)
+{
+ if (mipspmu)
+ mipspmu->stop();
+}
+
+/* This is needed by specific irq handlers in perf_event_*.c */
+static void
+handle_associated_event(struct cpu_hw_events *cpuc,
+ int idx, struct perf_sample_data *data, struct pt_regs *regs)
+{
+ struct perf_event *event = cpuc->events[idx];
+ struct hw_perf_event *hwc = &event->hw;
+
+ mipspmu_event_update(event, hwc, idx);
+ data->period = event->hw.last_period;
+ if (!mipspmu_event_set_period(event, hwc, idx))
+ return;
+
+ if (perf_event_overflow(event, 0, data, regs))
+ mipspmu->disable_event(idx);
+}
projects / platform / kernel / linux-rpi.git / commitdiff