Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1252 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
new file mode 100644
index 000000000..89eec5858
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -0,0 +1,1252 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2017-2018 Intel Corporation
+ */
+
+#include <linux/pm_runtime.h>
+
+#include "gt/intel_engine.h"
+#include "gt/intel_engine_pm.h"
+#include "gt/intel_engine_regs.h"
+#include "gt/intel_engine_user.h"
+#include "gt/intel_gt_pm.h"
+#include "gt/intel_gt_regs.h"
+#include "gt/intel_rc6.h"
+#include "gt/intel_rps.h"
+
+#include "i915_drv.h"
+#include "i915_pmu.h"
+#include "intel_pm.h"
+
+/* Frequency for the sampling timer for events which need it. */
+#define FREQUENCY 200
+#define PERIOD max_t(u64, 10000, NSEC_PER_SEC / FREQUENCY)
+
+#define ENGINE_SAMPLE_MASK \
+	(BIT(I915_SAMPLE_BUSY) | \
+	 BIT(I915_SAMPLE_WAIT) | \
+	 BIT(I915_SAMPLE_SEMA))
+
+static cpumask_t i915_pmu_cpumask;
+static unsigned int i915_pmu_target_cpu = -1;
+
+static u8 engine_config_sample(u64 config)
+{
+	return config & I915_PMU_SAMPLE_MASK;
+}
+
+static u8 engine_event_sample(struct perf_event *event)
+{
+	return engine_config_sample(event->attr.config);
+}
+
+static u8 engine_event_class(struct perf_event *event)
+{
+	return (event->attr.config >> I915_PMU_CLASS_SHIFT) & 0xff;
+}
+
+static u8 engine_event_instance(struct perf_event *event)
+{
+	return (event->attr.config >> I915_PMU_SAMPLE_BITS) & 0xff;
+}
+
+static bool is_engine_config(u64 config)
+{
+	return config < __I915_PMU_OTHER(0);
+}
+
+static unsigned int other_bit(const u64 config)
+{
+	unsigned int val;
+
+	switch (config) {
+	case I915_PMU_ACTUAL_FREQUENCY:
+		val =  __I915_PMU_ACTUAL_FREQUENCY_ENABLED;
+		break;
+	case I915_PMU_REQUESTED_FREQUENCY:
+		val = __I915_PMU_REQUESTED_FREQUENCY_ENABLED;
+		break;
+	case I915_PMU_RC6_RESIDENCY:
+		val = __I915_PMU_RC6_RESIDENCY_ENABLED;
+		break;
+	default:
+		/*
+		 * Events that do not require sampling, or tracking state
+		 * transitions between enabled and disabled can be ignored.
+		 */
+		return -1;
+	}
+
+	return I915_ENGINE_SAMPLE_COUNT + val;
+}
+
+static unsigned int config_bit(const u64 config)
+{
+	if (is_engine_config(config))
+		return engine_config_sample(config);
+	else
+		return other_bit(config);
+}
+
+static u64 config_mask(u64 config)
+{
+	return BIT_ULL(config_bit(config));
+}
+
+static bool is_engine_event(struct perf_event *event)
+{
+	return is_engine_config(event->attr.config);
+}
+
+static unsigned int event_bit(struct perf_event *event)
+{
+	return config_bit(event->attr.config);
+}
+
+static bool pmu_needs_timer(struct i915_pmu *pmu, bool gpu_active)
+{
+	struct drm_i915_private *i915 = container_of(pmu, typeof(*i915), pmu);
+	u32 enable;
+
+	/*
+	 * Only some counters need the sampling timer.
+	 *
+	 * We start with a bitmask of all currently enabled events.
+	 */
+	enable = pmu->enable;
+
+	/*
+	 * Mask out all the ones which do not need the timer, or in
+	 * other words keep all the ones that could need the timer.
+	 */
+	enable &= config_mask(I915_PMU_ACTUAL_FREQUENCY) |
+		  config_mask(I915_PMU_REQUESTED_FREQUENCY) |
+		  ENGINE_SAMPLE_MASK;
+
+	/*
+	 * When the GPU is idle per-engine counters do not need to be
+	 * running so clear those bits out.
+	 */
+	if (!gpu_active)
+		enable &= ~ENGINE_SAMPLE_MASK;
+	/*
+	 * Also there is software busyness tracking available we do not
+	 * need the timer for I915_SAMPLE_BUSY counter.
+	 */
+	else if (i915->caps.scheduler & I915_SCHEDULER_CAP_ENGINE_BUSY_STATS)
+		enable &= ~BIT(I915_SAMPLE_BUSY);
+
+	/*
+	 * If some bits remain it means we need the sampling timer running.
+	 */
+	return enable;
+}
+
+static u64 __get_rc6(struct intel_gt *gt)
+{
+	struct drm_i915_private *i915 = gt->i915;
+	u64 val;
+
+	val = intel_rc6_residency_ns(&gt->rc6, GEN6_GT_GFX_RC6);
+
+	if (HAS_RC6p(i915))
+		val += intel_rc6_residency_ns(&gt->rc6, GEN6_GT_GFX_RC6p);
+
+	if (HAS_RC6pp(i915))
+		val += intel_rc6_residency_ns(&gt->rc6, GEN6_GT_GFX_RC6pp);
+
+	return val;
+}
+
+static inline s64 ktime_since_raw(const ktime_t kt)
+{
+	return ktime_to_ns(ktime_sub(ktime_get_raw(), kt));
+}
+
+static u64 get_rc6(struct intel_gt *gt)
+{
+	struct drm_i915_private *i915 = gt->i915;
+	struct i915_pmu *pmu = &i915->pmu;
+	unsigned long flags;
+	bool awake = false;
+	u64 val;
+
+	if (intel_gt_pm_get_if_awake(gt)) {
+		val = __get_rc6(gt);
+		intel_gt_pm_put_async(gt);
+		awake = true;
+	}
+
+	spin_lock_irqsave(&pmu->lock, flags);
+
+	if (awake) {
+		pmu->sample[__I915_SAMPLE_RC6].cur = val;
+	} else {
+		/*
+		 * We think we are runtime suspended.
+		 *
+		 * Report the delta from when the device was suspended to now,
+		 * on top of the last known real value, as the approximated RC6
+		 * counter value.
+		 */
+		val = ktime_since_raw(pmu->sleep_last);
+		val += pmu->sample[__I915_SAMPLE_RC6].cur;
+	}
+
+	if (val < pmu->sample[__I915_SAMPLE_RC6_LAST_REPORTED].cur)
+		val = pmu->sample[__I915_SAMPLE_RC6_LAST_REPORTED].cur;
+	else
+		pmu->sample[__I915_SAMPLE_RC6_LAST_REPORTED].cur = val;
+
+	spin_unlock_irqrestore(&pmu->lock, flags);
+
+	return val;
+}
+
+static void init_rc6(struct i915_pmu *pmu)
+{
+	struct drm_i915_private *i915 = container_of(pmu, typeof(*i915), pmu);
+	intel_wakeref_t wakeref;
+
+	with_intel_runtime_pm(to_gt(i915)->uncore->rpm, wakeref) {
+		pmu->sample[__I915_SAMPLE_RC6].cur = __get_rc6(to_gt(i915));
+		pmu->sample[__I915_SAMPLE_RC6_LAST_REPORTED].cur =
+					pmu->sample[__I915_SAMPLE_RC6].cur;
+		pmu->sleep_last = ktime_get_raw();
+	}
+}
+
+static void park_rc6(struct drm_i915_private *i915)
+{
+	struct i915_pmu *pmu = &i915->pmu;
+
+	pmu->sample[__I915_SAMPLE_RC6].cur = __get_rc6(to_gt(i915));
+	pmu->sleep_last = ktime_get_raw();
+}
+
+static void __i915_pmu_maybe_start_timer(struct i915_pmu *pmu)
+{
+	if (!pmu->timer_enabled && pmu_needs_timer(pmu, true)) {
+		pmu->timer_enabled = true;
+		pmu->timer_last = ktime_get();
+		hrtimer_start_range_ns(&pmu->timer,
+				       ns_to_ktime(PERIOD), 0,
+				       HRTIMER_MODE_REL_PINNED);
+	}
+}
+
+void i915_pmu_gt_parked(struct drm_i915_private *i915)
+{
+	struct i915_pmu *pmu = &i915->pmu;
+
+	if (!pmu->base.event_init)
+		return;
+
+	spin_lock_irq(&pmu->lock);
+
+	park_rc6(i915);
+
+	/*
+	 * Signal sampling timer to stop if only engine events are enabled and
+	 * GPU went idle.
+	 */
+	pmu->timer_enabled = pmu_needs_timer(pmu, false);
+
+	spin_unlock_irq(&pmu->lock);
+}
+
+void i915_pmu_gt_unparked(struct drm_i915_private *i915)
+{
+	struct i915_pmu *pmu = &i915->pmu;
+
+	if (!pmu->base.event_init)
+		return;
+
+	spin_lock_irq(&pmu->lock);
+
+	/*
+	 * Re-enable sampling timer when GPU goes active.
+	 */
+	__i915_pmu_maybe_start_timer(pmu);
+
+	spin_unlock_irq(&pmu->lock);
+}
+
+static void
+add_sample(struct i915_pmu_sample *sample, u32 val)
+{
+	sample->cur += val;
+}
+
+static bool exclusive_mmio_access(const struct drm_i915_private *i915)
+{
+	/*
+	 * We have to avoid concurrent mmio cache line access on gen7 or
+	 * risk a machine hang. For a fun history lesson dig out the old
+	 * userspace intel_gpu_top and run it on Ivybridge or Haswell!
+	 */
+	return GRAPHICS_VER(i915) == 7;
+}
+
+static void engine_sample(struct intel_engine_cs *engine, unsigned int period_ns)
+{
+	struct intel_engine_pmu *pmu = &engine->pmu;
+	bool busy;
+	u32 val;
+
+	val = ENGINE_READ_FW(engine, RING_CTL);
+	if (val == 0) /* powerwell off => engine idle */
+		return;
+
+	if (val & RING_WAIT)
+		add_sample(&pmu->sample[I915_SAMPLE_WAIT], period_ns);
+	if (val & RING_WAIT_SEMAPHORE)
+		add_sample(&pmu->sample[I915_SAMPLE_SEMA], period_ns);
+
+	/* No need to sample when busy stats are supported. */
+	if (intel_engine_supports_stats(engine))
+		return;
+
+	/*
+	 * While waiting on a semaphore or event, MI_MODE reports the
+	 * ring as idle. However, previously using the seqno, and with
+	 * execlists sampling, we account for the ring waiting as the
+	 * engine being busy. Therefore, we record the sample as being
+	 * busy if either waiting or !idle.
+	 */
+	busy = val & (RING_WAIT_SEMAPHORE | RING_WAIT);
+	if (!busy) {
+		val = ENGINE_READ_FW(engine, RING_MI_MODE);
+		busy = !(val & MODE_IDLE);
+	}
+	if (busy)
+		add_sample(&pmu->sample[I915_SAMPLE_BUSY], period_ns);
+}
+
+static void
+engines_sample(struct intel_gt *gt, unsigned int period_ns)
+{
+	struct drm_i915_private *i915 = gt->i915;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	unsigned long flags;
+
+	if ((i915->pmu.enable & ENGINE_SAMPLE_MASK) == 0)
+		return;
+
+	if (!intel_gt_pm_is_awake(gt))
+		return;
+
+	for_each_engine(engine, gt, id) {
+		if (!intel_engine_pm_get_if_awake(engine))
+			continue;
+
+		if (exclusive_mmio_access(i915)) {
+			spin_lock_irqsave(&engine->uncore->lock, flags);
+			engine_sample(engine, period_ns);
+			spin_unlock_irqrestore(&engine->uncore->lock, flags);
+		} else {
+			engine_sample(engine, period_ns);
+		}
+
+		intel_engine_pm_put_async(engine);
+	}
+}
+
+static void
+add_sample_mult(struct i915_pmu_sample *sample, u32 val, u32 mul)
+{
+	sample->cur += mul_u32_u32(val, mul);
+}
+
+static bool frequency_sampling_enabled(struct i915_pmu *pmu)
+{
+	return pmu->enable &
+	       (config_mask(I915_PMU_ACTUAL_FREQUENCY) |
+		config_mask(I915_PMU_REQUESTED_FREQUENCY));
+}
+
+static void
+frequency_sample(struct intel_gt *gt, unsigned int period_ns)
+{
+	struct drm_i915_private *i915 = gt->i915;
+	struct intel_uncore *uncore = gt->uncore;
+	struct i915_pmu *pmu = &i915->pmu;
+	struct intel_rps *rps = &gt->rps;
+
+	if (!frequency_sampling_enabled(pmu))
+		return;
+
+	/* Report 0/0 (actual/requested) frequency while parked. */
+	if (!intel_gt_pm_get_if_awake(gt))
+		return;
+
+	if (pmu->enable & config_mask(I915_PMU_ACTUAL_FREQUENCY)) {
+		u32 val;
+
+		/*
+		 * We take a quick peek here without using forcewake
+		 * so that we don't perturb the system under observation
+		 * (forcewake => !rc6 => increased power use). We expect
+		 * that if the read fails because it is outside of the
+		 * mmio power well, then it will return 0 -- in which
+		 * case we assume the system is running at the intended
+		 * frequency. Fortunately, the read should rarely fail!
+		 */
+		val = intel_uncore_read_fw(uncore, GEN6_RPSTAT1);
+		if (val)
+			val = intel_rps_get_cagf(rps, val);
+		else
+			val = rps->cur_freq;
+
+		add_sample_mult(&pmu->sample[__I915_SAMPLE_FREQ_ACT],
+				intel_gpu_freq(rps, val), period_ns / 1000);
+	}
+
+	if (pmu->enable & config_mask(I915_PMU_REQUESTED_FREQUENCY)) {
+		add_sample_mult(&pmu->sample[__I915_SAMPLE_FREQ_REQ],
+				intel_rps_get_requested_frequency(rps),
+				period_ns / 1000);
+	}
+
+	intel_gt_pm_put_async(gt);
+}
+
+static enum hrtimer_restart i915_sample(struct hrtimer *hrtimer)
+{
+	struct drm_i915_private *i915 =
+		container_of(hrtimer, struct drm_i915_private, pmu.timer);
+	struct i915_pmu *pmu = &i915->pmu;
+	struct intel_gt *gt = to_gt(i915);
+	unsigned int period_ns;
+	ktime_t now;
+
+	if (!READ_ONCE(pmu->timer_enabled))
+		return HRTIMER_NORESTART;
+
+	now = ktime_get();
+	period_ns = ktime_to_ns(ktime_sub(now, pmu->timer_last));
+	pmu->timer_last = now;
+
+	/*
+	 * Strictly speaking the passed in period may not be 100% accurate for
+	 * all internal calculation, since some amount of time can be spent on
+	 * grabbing the forcewake. However the potential error from timer call-
+	 * back delay greatly dominates this so we keep it simple.
+	 */
+	engines_sample(gt, period_ns);
+	frequency_sample(gt, period_ns);
+
+	hrtimer_forward(hrtimer, now, ns_to_ktime(PERIOD));
+
+	return HRTIMER_RESTART;
+}
+
+static void i915_pmu_event_destroy(struct perf_event *event)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+
+	drm_WARN_ON(&i915->drm, event->parent);
+
+	drm_dev_put(&i915->drm);
+}
+
+static int
+engine_event_status(struct intel_engine_cs *engine,
+		    enum drm_i915_pmu_engine_sample sample)
+{
+	switch (sample) {
+	case I915_SAMPLE_BUSY:
+	case I915_SAMPLE_WAIT:
+		break;
+	case I915_SAMPLE_SEMA:
+		if (GRAPHICS_VER(engine->i915) < 6)
+			return -ENODEV;
+		break;
+	default:
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+static int
+config_status(struct drm_i915_private *i915, u64 config)
+{
+	struct intel_gt *gt = to_gt(i915);
+
+	switch (config) {
+	case I915_PMU_ACTUAL_FREQUENCY:
+		if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
+			/* Requires a mutex for sampling! */
+			return -ENODEV;
+		fallthrough;
+	case I915_PMU_REQUESTED_FREQUENCY:
+		if (GRAPHICS_VER(i915) < 6)
+			return -ENODEV;
+		break;
+	case I915_PMU_INTERRUPTS:
+		break;
+	case I915_PMU_RC6_RESIDENCY:
+		if (!gt->rc6.supported)
+			return -ENODEV;
+		break;
+	case I915_PMU_SOFTWARE_GT_AWAKE_TIME:
+		break;
+	default:
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+static int engine_event_init(struct perf_event *event)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+	struct intel_engine_cs *engine;
+
+	engine = intel_engine_lookup_user(i915, engine_event_class(event),
+					  engine_event_instance(event));
+	if (!engine)
+		return -ENODEV;
+
+	return engine_event_status(engine, engine_event_sample(event));
+}
+
+static int i915_pmu_event_init(struct perf_event *event)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+	struct i915_pmu *pmu = &i915->pmu;
+	int ret;
+
+	if (pmu->closed)
+		return -ENODEV;
+
+	if (event->attr.type != event->pmu->type)
+		return -ENOENT;
+
+	/* unsupported modes and filters */
+	if (event->attr.sample_period) /* no sampling */
+		return -EINVAL;
+
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	if (event->cpu < 0)
+		return -EINVAL;
+
+	/* only allow running on one cpu at a time */
+	if (!cpumask_test_cpu(event->cpu, &i915_pmu_cpumask))
+		return -EINVAL;
+
+	if (is_engine_event(event))
+		ret = engine_event_init(event);
+	else
+		ret = config_status(i915, event->attr.config);
+	if (ret)
+		return ret;
+
+	if (!event->parent) {
+		drm_dev_get(&i915->drm);
+		event->destroy = i915_pmu_event_destroy;
+	}
+
+	return 0;
+}
+
+static u64 __i915_pmu_event_read(struct perf_event *event)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+	struct i915_pmu *pmu = &i915->pmu;
+	u64 val = 0;
+
+	if (is_engine_event(event)) {
+		u8 sample = engine_event_sample(event);
+		struct intel_engine_cs *engine;
+
+		engine = intel_engine_lookup_user(i915,
+						  engine_event_class(event),
+						  engine_event_instance(event));
+
+		if (drm_WARN_ON_ONCE(&i915->drm, !engine)) {
+			/* Do nothing */
+		} else if (sample == I915_SAMPLE_BUSY &&
+			   intel_engine_supports_stats(engine)) {
+			ktime_t unused;
+
+			val = ktime_to_ns(intel_engine_get_busy_time(engine,
+								     &unused));
+		} else {
+			val = engine->pmu.sample[sample].cur;
+		}
+	} else {
+		switch (event->attr.config) {
+		case I915_PMU_ACTUAL_FREQUENCY:
+			val =
+			   div_u64(pmu->sample[__I915_SAMPLE_FREQ_ACT].cur,
+				   USEC_PER_SEC /* to MHz */);
+			break;
+		case I915_PMU_REQUESTED_FREQUENCY:
+			val =
+			   div_u64(pmu->sample[__I915_SAMPLE_FREQ_REQ].cur,
+				   USEC_PER_SEC /* to MHz */);
+			break;
+		case I915_PMU_INTERRUPTS:
+			val = READ_ONCE(pmu->irq_count);
+			break;
+		case I915_PMU_RC6_RESIDENCY:
+			val = get_rc6(to_gt(i915));
+			break;
+		case I915_PMU_SOFTWARE_GT_AWAKE_TIME:
+			val = ktime_to_ns(intel_gt_get_awake_time(to_gt(i915)));
+			break;
+		}
+	}
+
+	return val;
+}
+
+static void i915_pmu_event_read(struct perf_event *event)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+	struct hw_perf_event *hwc = &event->hw;
+	struct i915_pmu *pmu = &i915->pmu;
+	u64 prev, new;
+
+	if (pmu->closed) {
+		event->hw.state = PERF_HES_STOPPED;
+		return;
+	}
+again:
+	prev = local64_read(&hwc->prev_count);
+	new = __i915_pmu_event_read(event);
+
+	if (local64_cmpxchg(&hwc->prev_count, prev, new) != prev)
+		goto again;
+
+	local64_add(new - prev, &event->count);
+}
+
+static void i915_pmu_enable(struct perf_event *event)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+	struct i915_pmu *pmu = &i915->pmu;
+	unsigned long flags;
+	unsigned int bit;
+
+	bit = event_bit(event);
+	if (bit == -1)
+		goto update;
+
+	spin_lock_irqsave(&pmu->lock, flags);
+
+	/*
+	 * Update the bitmask of enabled events and increment
+	 * the event reference counter.
+	 */
+	BUILD_BUG_ON(ARRAY_SIZE(pmu->enable_count) != I915_PMU_MASK_BITS);
+	GEM_BUG_ON(bit >= ARRAY_SIZE(pmu->enable_count));
+	GEM_BUG_ON(pmu->enable_count[bit] == ~0);
+
+	pmu->enable |= BIT_ULL(bit);
+	pmu->enable_count[bit]++;
+
+	/*
+	 * Start the sampling timer if needed and not already enabled.
+	 */
+	__i915_pmu_maybe_start_timer(pmu);
+
+	/*
+	 * For per-engine events the bitmask and reference counting
+	 * is stored per engine.
+	 */
+	if (is_engine_event(event)) {
+		u8 sample = engine_event_sample(event);
+		struct intel_engine_cs *engine;
+
+		engine = intel_engine_lookup_user(i915,
+						  engine_event_class(event),
+						  engine_event_instance(event));
+
+		BUILD_BUG_ON(ARRAY_SIZE(engine->pmu.enable_count) !=
+			     I915_ENGINE_SAMPLE_COUNT);
+		BUILD_BUG_ON(ARRAY_SIZE(engine->pmu.sample) !=
+			     I915_ENGINE_SAMPLE_COUNT);
+		GEM_BUG_ON(sample >= ARRAY_SIZE(engine->pmu.enable_count));
+		GEM_BUG_ON(sample >= ARRAY_SIZE(engine->pmu.sample));
+		GEM_BUG_ON(engine->pmu.enable_count[sample] == ~0);
+
+		engine->pmu.enable |= BIT(sample);
+		engine->pmu.enable_count[sample]++;
+	}
+
+	spin_unlock_irqrestore(&pmu->lock, flags);
+
+update:
+	/*
+	 * Store the current counter value so we can report the correct delta
+	 * for all listeners. Even when the event was already enabled and has
+	 * an existing non-zero value.
+	 */
+	local64_set(&event->hw.prev_count, __i915_pmu_event_read(event));
+}
+
+static void i915_pmu_disable(struct perf_event *event)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+	unsigned int bit = event_bit(event);
+	struct i915_pmu *pmu = &i915->pmu;
+	unsigned long flags;
+
+	if (bit == -1)
+		return;
+
+	spin_lock_irqsave(&pmu->lock, flags);
+
+	if (is_engine_event(event)) {
+		u8 sample = engine_event_sample(event);
+		struct intel_engine_cs *engine;
+
+		engine = intel_engine_lookup_user(i915,
+						  engine_event_class(event),
+						  engine_event_instance(event));
+
+		GEM_BUG_ON(sample >= ARRAY_SIZE(engine->pmu.enable_count));
+		GEM_BUG_ON(sample >= ARRAY_SIZE(engine->pmu.sample));
+		GEM_BUG_ON(engine->pmu.enable_count[sample] == 0);
+
+		/*
+		 * Decrement the reference count and clear the enabled
+		 * bitmask when the last listener on an event goes away.
+		 */
+		if (--engine->pmu.enable_count[sample] == 0)
+			engine->pmu.enable &= ~BIT(sample);
+	}
+
+	GEM_BUG_ON(bit >= ARRAY_SIZE(pmu->enable_count));
+	GEM_BUG_ON(pmu->enable_count[bit] == 0);
+	/*
+	 * Decrement the reference count and clear the enabled
+	 * bitmask when the last listener on an event goes away.
+	 */
+	if (--pmu->enable_count[bit] == 0) {
+		pmu->enable &= ~BIT_ULL(bit);
+		pmu->timer_enabled &= pmu_needs_timer(pmu, true);
+	}
+
+	spin_unlock_irqrestore(&pmu->lock, flags);
+}
+
+static void i915_pmu_event_start(struct perf_event *event, int flags)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+	struct i915_pmu *pmu = &i915->pmu;
+
+	if (pmu->closed)
+		return;
+
+	i915_pmu_enable(event);
+	event->hw.state = 0;
+}
+
+static void i915_pmu_event_stop(struct perf_event *event, int flags)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+	struct i915_pmu *pmu = &i915->pmu;
+
+	if (pmu->closed)
+		goto out;
+
+	if (flags & PERF_EF_UPDATE)
+		i915_pmu_event_read(event);
+	i915_pmu_disable(event);
+
+out:
+	event->hw.state = PERF_HES_STOPPED;
+}
+
+static int i915_pmu_event_add(struct perf_event *event, int flags)
+{
+	struct drm_i915_private *i915 =
+		container_of(event->pmu, typeof(*i915), pmu.base);
+	struct i915_pmu *pmu = &i915->pmu;
+
+	if (pmu->closed)
+		return -ENODEV;
+
+	if (flags & PERF_EF_START)
+		i915_pmu_event_start(event, flags);
+
+	return 0;
+}
+
+static void i915_pmu_event_del(struct perf_event *event, int flags)
+{
+	i915_pmu_event_stop(event, PERF_EF_UPDATE);
+}
+
+static int i915_pmu_event_event_idx(struct perf_event *event)
+{
+	return 0;
+}
+
+struct i915_str_attribute {
+	struct device_attribute attr;
+	const char *str;
+};
+
+static ssize_t i915_pmu_format_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct i915_str_attribute *eattr;
+
+	eattr = container_of(attr, struct i915_str_attribute, attr);
+	return sprintf(buf, "%s\n", eattr->str);
+}
+
+#define I915_PMU_FORMAT_ATTR(_name, _config) \
+	(&((struct i915_str_attribute[]) { \
+		{ .attr = __ATTR(_name, 0444, i915_pmu_format_show, NULL), \
+		  .str = _config, } \
+	})[0].attr.attr)
+
+static struct attribute *i915_pmu_format_attrs[] = {
+	I915_PMU_FORMAT_ATTR(i915_eventid, "config:0-20"),
+	NULL,
+};
+
+static const struct attribute_group i915_pmu_format_attr_group = {
+	.name = "format",
+	.attrs = i915_pmu_format_attrs,
+};
+
+struct i915_ext_attribute {
+	struct device_attribute attr;
+	unsigned long val;
+};
+
+static ssize_t i915_pmu_event_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct i915_ext_attribute *eattr;
+
+	eattr = container_of(attr, struct i915_ext_attribute, attr);
+	return sprintf(buf, "config=0x%lx\n", eattr->val);
+}
+
+static ssize_t cpumask_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	return cpumap_print_to_pagebuf(true, buf, &i915_pmu_cpumask);
+}
+
+static DEVICE_ATTR_RO(cpumask);
+
+static struct attribute *i915_cpumask_attrs[] = {
+	&dev_attr_cpumask.attr,
+	NULL,
+};
+
+static const struct attribute_group i915_pmu_cpumask_attr_group = {
+	.attrs = i915_cpumask_attrs,
+};
+
+#define __event(__config, __name, __unit) \
+{ \
+	.config = (__config), \
+	.name = (__name), \
+	.unit = (__unit), \
+}
+
+#define __engine_event(__sample, __name) \
+{ \
+	.sample = (__sample), \
+	.name = (__name), \
+}
+
+static struct i915_ext_attribute *
+add_i915_attr(struct i915_ext_attribute *attr, const char *name, u64 config)
+{
+	sysfs_attr_init(&attr->attr.attr);
+	attr->attr.attr.name = name;
+	attr->attr.attr.mode = 0444;
+	attr->attr.show = i915_pmu_event_show;
+	attr->val = config;
+
+	return ++attr;
+}
+
+static struct perf_pmu_events_attr *
+add_pmu_attr(struct perf_pmu_events_attr *attr, const char *name,
+	     const char *str)
+{
+	sysfs_attr_init(&attr->attr.attr);
+	attr->attr.attr.name = name;
+	attr->attr.attr.mode = 0444;
+	attr->attr.show = perf_event_sysfs_show;
+	attr->event_str = str;
+
+	return ++attr;
+}
+
+static struct attribute **
+create_event_attributes(struct i915_pmu *pmu)
+{
+	struct drm_i915_private *i915 = container_of(pmu, typeof(*i915), pmu);
+	static const struct {
+		u64 config;
+		const char *name;
+		const char *unit;
+	} events[] = {
+		__event(I915_PMU_ACTUAL_FREQUENCY, "actual-frequency", "M"),
+		__event(I915_PMU_REQUESTED_FREQUENCY, "requested-frequency", "M"),
+		__event(I915_PMU_INTERRUPTS, "interrupts", NULL),
+		__event(I915_PMU_RC6_RESIDENCY, "rc6-residency", "ns"),
+		__event(I915_PMU_SOFTWARE_GT_AWAKE_TIME, "software-gt-awake-time", "ns"),
+	};
+	static const struct {
+		enum drm_i915_pmu_engine_sample sample;
+		char *name;
+	} engine_events[] = {
+		__engine_event(I915_SAMPLE_BUSY, "busy"),
+		__engine_event(I915_SAMPLE_SEMA, "sema"),
+		__engine_event(I915_SAMPLE_WAIT, "wait"),
+	};
+	unsigned int count = 0;
+	struct perf_pmu_events_attr *pmu_attr = NULL, *pmu_iter;
+	struct i915_ext_attribute *i915_attr = NULL, *i915_iter;
+	struct attribute **attr = NULL, **attr_iter;
+	struct intel_engine_cs *engine;
+	unsigned int i;
+
+	/* Count how many counters we will be exposing. */
+	for (i = 0; i < ARRAY_SIZE(events); i++) {
+		if (!config_status(i915, events[i].config))
+			count++;
+	}
+
+	for_each_uabi_engine(engine, i915) {
+		for (i = 0; i < ARRAY_SIZE(engine_events); i++) {
+			if (!engine_event_status(engine,
+						 engine_events[i].sample))
+				count++;
+		}
+	}
+
+	/* Allocate attribute objects and table. */
+	i915_attr = kcalloc(count, sizeof(*i915_attr), GFP_KERNEL);
+	if (!i915_attr)
+		goto err_alloc;
+
+	pmu_attr = kcalloc(count, sizeof(*pmu_attr), GFP_KERNEL);
+	if (!pmu_attr)
+		goto err_alloc;
+
+	/* Max one pointer of each attribute type plus a termination entry. */
+	attr = kcalloc(count * 2 + 1, sizeof(*attr), GFP_KERNEL);
+	if (!attr)
+		goto err_alloc;
+
+	i915_iter = i915_attr;
+	pmu_iter = pmu_attr;
+	attr_iter = attr;
+
+	/* Initialize supported non-engine counters. */
+	for (i = 0; i < ARRAY_SIZE(events); i++) {
+		char *str;
+
+		if (config_status(i915, events[i].config))
+			continue;
+
+		str = kstrdup(events[i].name, GFP_KERNEL);
+		if (!str)
+			goto err;
+
+		*attr_iter++ = &i915_iter->attr.attr;
+		i915_iter = add_i915_attr(i915_iter, str, events[i].config);
+
+		if (events[i].unit) {
+			str = kasprintf(GFP_KERNEL, "%s.unit", events[i].name);
+			if (!str)
+				goto err;
+
+			*attr_iter++ = &pmu_iter->attr.attr;
+			pmu_iter = add_pmu_attr(pmu_iter, str, events[i].unit);
+		}
+	}
+
+	/* Initialize supported engine counters. */
+	for_each_uabi_engine(engine, i915) {
+		for (i = 0; i < ARRAY_SIZE(engine_events); i++) {
+			char *str;
+
+			if (engine_event_status(engine,
+						engine_events[i].sample))
+				continue;
+
+			str = kasprintf(GFP_KERNEL, "%s-%s",
+					engine->name, engine_events[i].name);
+			if (!str)
+				goto err;
+
+			*attr_iter++ = &i915_iter->attr.attr;
+			i915_iter =
+				add_i915_attr(i915_iter, str,
+					      __I915_PMU_ENGINE(engine->uabi_class,
+								engine->uabi_instance,
+								engine_events[i].sample));
+
+			str = kasprintf(GFP_KERNEL, "%s-%s.unit",
+					engine->name, engine_events[i].name);
+			if (!str)
+				goto err;
+
+			*attr_iter++ = &pmu_iter->attr.attr;
+			pmu_iter = add_pmu_attr(pmu_iter, str, "ns");
+		}
+	}
+
+	pmu->i915_attr = i915_attr;
+	pmu->pmu_attr = pmu_attr;
+
+	return attr;
+
+err:;
+	for (attr_iter = attr; *attr_iter; attr_iter++)
+		kfree((*attr_iter)->name);
+
+err_alloc:
+	kfree(attr);
+	kfree(i915_attr);
+	kfree(pmu_attr);
+
+	return NULL;
+}
+
+static void free_event_attributes(struct i915_pmu *pmu)
+{
+	struct attribute **attr_iter = pmu->events_attr_group.attrs;
+
+	for (; *attr_iter; attr_iter++)
+		kfree((*attr_iter)->name);
+
+	kfree(pmu->events_attr_group.attrs);
+	kfree(pmu->i915_attr);
+	kfree(pmu->pmu_attr);
+
+	pmu->events_attr_group.attrs = NULL;
+	pmu->i915_attr = NULL;
+	pmu->pmu_attr = NULL;
+}
+
+static int i915_pmu_cpu_online(unsigned int cpu, struct hlist_node *node)
+{
+	struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node);
+
+	GEM_BUG_ON(!pmu->base.event_init);
+
+	/* Select the first online CPU as a designated reader. */
+	if (cpumask_empty(&i915_pmu_cpumask))
+		cpumask_set_cpu(cpu, &i915_pmu_cpumask);
+
+	return 0;
+}
+
+static int i915_pmu_cpu_offline(unsigned int cpu, struct hlist_node *node)
+{
+	struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node);
+	unsigned int target = i915_pmu_target_cpu;
+
+	GEM_BUG_ON(!pmu->base.event_init);
+
+	/*
+	 * Unregistering an instance generates a CPU offline event which we must
+	 * ignore to avoid incorrectly modifying the shared i915_pmu_cpumask.
+	 */
+	if (pmu->closed)
+		return 0;
+
+	if (cpumask_test_and_clear_cpu(cpu, &i915_pmu_cpumask)) {
+		target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu);
+
+		/* Migrate events if there is a valid target */
+		if (target < nr_cpu_ids) {
+			cpumask_set_cpu(target, &i915_pmu_cpumask);
+			i915_pmu_target_cpu = target;
+		}
+	}
+
+	if (target < nr_cpu_ids && target != pmu->cpuhp.cpu) {
+		perf_pmu_migrate_context(&pmu->base, cpu, target);
+		pmu->cpuhp.cpu = target;
+	}
+
+	return 0;
+}
+
+static enum cpuhp_state cpuhp_slot = CPUHP_INVALID;
+
+int i915_pmu_init(void)
+{
+	int ret;
+
+	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
+				      "perf/x86/intel/i915:online",
+				      i915_pmu_cpu_online,
+				      i915_pmu_cpu_offline);
+	if (ret < 0)
+		pr_notice("Failed to setup cpuhp state for i915 PMU! (%d)\n",
+			  ret);
+	else
+		cpuhp_slot = ret;
+
+	return 0;
+}
+
+void i915_pmu_exit(void)
+{
+	if (cpuhp_slot != CPUHP_INVALID)
+		cpuhp_remove_multi_state(cpuhp_slot);
+}
+
+static int i915_pmu_register_cpuhp_state(struct i915_pmu *pmu)
+{
+	if (cpuhp_slot == CPUHP_INVALID)
+		return -EINVAL;
+
+	return cpuhp_state_add_instance(cpuhp_slot, &pmu->cpuhp.node);
+}
+
+static void i915_pmu_unregister_cpuhp_state(struct i915_pmu *pmu)
+{
+	cpuhp_state_remove_instance(cpuhp_slot, &pmu->cpuhp.node);
+}
+
+static bool is_igp(struct drm_i915_private *i915)
+{
+	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
+
+	/* IGP is 0000:00:02.0 */
+	return pci_domain_nr(pdev->bus) == 0 &&
+	       pdev->bus->number == 0 &&
+	       PCI_SLOT(pdev->devfn) == 2 &&
+	       PCI_FUNC(pdev->devfn) == 0;
+}
+
+void i915_pmu_register(struct drm_i915_private *i915)
+{
+	struct i915_pmu *pmu = &i915->pmu;
+	const struct attribute_group *attr_groups[] = {
+		&i915_pmu_format_attr_group,
+		&pmu->events_attr_group,
+		&i915_pmu_cpumask_attr_group,
+		NULL
+	};
+
+	int ret = -ENOMEM;
+
+	if (GRAPHICS_VER(i915) <= 2) {
+		drm_info(&i915->drm, "PMU not supported for this GPU.");
+		return;
+	}
+
+	spin_lock_init(&pmu->lock);
+	hrtimer_init(&pmu->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	pmu->timer.function = i915_sample;
+	pmu->cpuhp.cpu = -1;
+	init_rc6(pmu);
+
+	if (!is_igp(i915)) {
+		pmu->name = kasprintf(GFP_KERNEL,
+				      "i915_%s",
+				      dev_name(i915->drm.dev));
+		if (pmu->name) {
+			/* tools/perf reserves colons as special. */
+			strreplace((char *)pmu->name, ':', '_');
+		}
+	} else {
+		pmu->name = "i915";
+	}
+	if (!pmu->name)
+		goto err;
+
+	pmu->events_attr_group.name = "events";
+	pmu->events_attr_group.attrs = create_event_attributes(pmu);
+	if (!pmu->events_attr_group.attrs)
+		goto err_name;
+
+	pmu->base.attr_groups = kmemdup(attr_groups, sizeof(attr_groups),
+					GFP_KERNEL);
+	if (!pmu->base.attr_groups)
+		goto err_attr;
+
+	pmu->base.module	= THIS_MODULE;
+	pmu->base.task_ctx_nr	= perf_invalid_context;
+	pmu->base.event_init	= i915_pmu_event_init;
+	pmu->base.add		= i915_pmu_event_add;
+	pmu->base.del		= i915_pmu_event_del;
+	pmu->base.start		= i915_pmu_event_start;
+	pmu->base.stop		= i915_pmu_event_stop;
+	pmu->base.read		= i915_pmu_event_read;
+	pmu->base.event_idx	= i915_pmu_event_event_idx;
+
+	ret = perf_pmu_register(&pmu->base, pmu->name, -1);
+	if (ret)
+		goto err_groups;
+
+	ret = i915_pmu_register_cpuhp_state(pmu);
+	if (ret)
+		goto err_unreg;
+
+	return;
+
+err_unreg:
+	perf_pmu_unregister(&pmu->base);
+err_groups:
+	kfree(pmu->base.attr_groups);
+err_attr:
+	pmu->base.event_init = NULL;
+	free_event_attributes(pmu);
+err_name:
+	if (!is_igp(i915))
+		kfree(pmu->name);
+err:
+	drm_notice(&i915->drm, "Failed to register PMU!\n");
+}
+
+void i915_pmu_unregister(struct drm_i915_private *i915)
+{
+	struct i915_pmu *pmu = &i915->pmu;
+
+	if (!pmu->base.event_init)
+		return;
+
+	/*
+	 * "Disconnect" the PMU callbacks - since all are atomic synchronize_rcu
+	 * ensures all currently executing ones will have exited before we
+	 * proceed with unregistration.
+	 */
+	pmu->closed = true;
+	synchronize_rcu();
+
+	hrtimer_cancel(&pmu->timer);
+
+	i915_pmu_unregister_cpuhp_state(pmu);
+
+	perf_pmu_unregister(&pmu->base);
+	pmu->base.event_init = NULL;
+	kfree(pmu->base.attr_groups);
+	if (!is_igp(i915))
+		kfree(pmu->name);
+	free_event_attributes(pmu);
+}