Merge tag 'block-5.11-2021-01-10' of git://git.kernel.dk/linux-block

[linux/fpc-iii.git] / drivers / gpu / drm / i915 / i915_pmu.c

/*
 * 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_user.h"
#include "gt/intel_gt_pm.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))

#define ENGINE_SAMPLE_BITS (1 << I915_PMU_SAMPLE_BITS)

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 config_enabled_bit(u64 config)
{
        if (is_engine_config(config))
                return engine_config_sample(config);
        else
                return ENGINE_SAMPLE_BITS + (config - __I915_PMU_OTHER(0));
}

static u64 config_enabled_mask(u64 config)
{
        return BIT_ULL(config_enabled_bit(config));
}

static bool is_engine_event(struct perf_event *event)
{
        return is_engine_config(event->attr.config);
}

static unsigned int event_enabled_bit(struct perf_event *event)
{
        return config_enabled_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);
        u64 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_enabled_mask(I915_PMU_ACTUAL_FREQUENCY) |
                  config_enabled_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,
                                     IS_VALLEYVIEW(i915) ?
                                     VLV_GT_RENDER_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;
}

#if IS_ENABLED(CONFIG_PM)

static inline s64 ktime_since(const ktime_t kt)
{
        return ktime_to_ns(ktime_sub(ktime_get(), 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(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 park_rc6(struct drm_i915_private *i915)
{
        struct i915_pmu *pmu = &i915->pmu;

        if (pmu->enable & config_enabled_mask(I915_PMU_RC6_RESIDENCY))
                pmu->sample[__I915_SAMPLE_RC6].cur = __get_rc6(&i915->gt);

        pmu->sleep_last = ktime_get();
}

#else

static u64 get_rc6(struct intel_gt *gt)
{
        return __get_rc6(gt);
}

static void park_rc6(struct drm_i915_private *i915) {}

#endif

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 IS_GEN(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_enabled_mask(I915_PMU_ACTUAL_FREQUENCY) |
                config_enabled_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_enabled_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_enabled_mask(I915_PMU_REQUESTED_FREQUENCY)) {
                add_sample_mult(&pmu->sample[__I915_SAMPLE_FREQ_REQ],
                                intel_gpu_freq(rps, rps->cur_freq),
                                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 = &i915->gt;
        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 (INTEL_GEN(engine->i915) < 6)
                        return -ENODEV;
                break;
        default:
                return -ENOENT;
        }

        return 0;
}

static int
config_status(struct drm_i915_private *i915, u64 config)
{
        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 (INTEL_GEN(i915) < 6)
                        return -ENODEV;
                break;
        case I915_PMU_INTERRUPTS:
                break;
        case I915_PMU_RC6_RESIDENCY:
                if (!HAS_RC6(i915))
                        return -ENODEV;
                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(&i915->gt);
                        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);
        unsigned int bit = event_enabled_bit(event);
        struct i915_pmu *pmu = &i915->pmu;
        intel_wakeref_t wakeref;
        unsigned long flags;

        wakeref = intel_runtime_pm_get(&i915->runtime_pm);
        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);

        if (pmu->enable_count[bit] == 0 &&
            config_enabled_mask(I915_PMU_RC6_RESIDENCY) & BIT_ULL(bit)) {
                pmu->sample[__I915_SAMPLE_RC6_LAST_REPORTED].cur = 0;
                pmu->sample[__I915_SAMPLE_RC6].cur = __get_rc6(&i915->gt);
                pmu->sleep_last = ktime_get();
        }

        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);

        /*
         * 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));

        intel_runtime_pm_put(&i915->runtime_pm, wakeref);
}

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_enabled_bit(event);
        struct i915_pmu *pmu = &i915->pmu;
        unsigned long flags;

        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)
{
        if (flags & PERF_EF_UPDATE)
                i915_pmu_event_read(event);
        i915_pmu_disable(event);
        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
i915_pmu_get_attr_cpumask(struct device *dev,
                          struct device_attribute *attr,
                          char *buf)
{
        return cpumap_print_to_pagebuf(true, buf, &i915_pmu_cpumask);
}

static DEVICE_ATTR(cpumask, 0444, i915_pmu_get_attr_cpumask, NULL);

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"),
        };
        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_weight(&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;

void 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;
}

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 = i915->drm.pdev;

        /* 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 (INTEL_GEN(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;

        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);
}