[PATCH 4/4] hmm

[Chris Wilson]

---
 drivers/gpu/drm/i915/gt/intel_engine_types.h |  5 ++
 drivers/gpu/drm/i915/gt/intel_rps.c          | 61 +++++++++++++++++++-
 drivers/gpu/drm/i915/gt/intel_rps.h          | 10 ++++
 drivers/gpu/drm/i915/gt/intel_rps_types.h    |  4 ++
 4 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index d7250b2d4175..b2c3e8df3eba 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -551,6 +551,11 @@ struct intel_engine_cs {
 		 * Idle is defined as active == 0, active is active > 0.
 		 */
 		ktime_t start;
+
+		/**
+		 * @rps: Utilisation at last RPS sampling.
+		 */
+		ktime_t rps;
 	} stats;
 
 	struct {
diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
index 58a10b3d60ba..85ad7a799d87 100644
--- a/drivers/gpu/drm/i915/gt/intel_rps.c
+++ b/drivers/gpu/drm/i915/gt/intel_rps.c
@@ -45,6 +45,56 @@ static inline void set(struct intel_uncore *uncore, i915_reg_t reg, u32 val)
 	intel_uncore_write_fw(uncore, reg, val);
 }
 
+static void rps_timer(struct timer_list *t)
+{
+	struct intel_rps *rps = from_timer(rps, t, timer);
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	ktime_t dt, last;
+	s64 max_busy = 0;
+
+	for_each_engine(engine, rps_to_gt(rps), id) {
+		dt = intel_engine_get_busy_time(engine);
+		last = engine->stats.rps;
+		engine->stats.rps = dt;
+
+		max_busy = max(max_busy, ktime_to_ns(ktime_sub(dt, last)));
+	}
+
+	dt = ktime_get();
+	last = rps->pm_timestamp;
+	rps->pm_timestamp = dt;
+
+	if (intel_rps_is_active(rps)) {
+		dt = ktime_sub(dt, last);
+
+		if (5 * max_busy > 4 * dt &&
+		    rps->cur_freq < rps->max_freq_softlimit) {
+			rps->pm_iir |= GEN6_PM_RP_UP_THRESHOLD;
+			schedule_work(&rps->work);
+		}
+		if (max_busy < 2 * dt &&
+		    rps->cur_freq > rps->min_freq_softlimit) {
+			rps->pm_iir |= GEN6_PM_RP_DOWN_THRESHOLD;
+			schedule_work(&rps->work);
+		}
+
+		mod_timer(&rps->timer, jiffies + msecs_to_jiffies_timeout(5));
+	}
+}
+
+static void rps_start_timer(struct intel_rps *rps)
+{
+	rps->pm_timestamp = ktime_sub(ktime_get(), rps->pm_timestamp);
+	mod_timer(&rps->timer, jiffies + msecs_to_jiffies_timeout(5));
+}
+
+static void rps_stop_timer(struct intel_rps *rps)
+{
+	del_timer_sync(&rps->timer);
+	rps->pm_timestamp = ktime_sub(ktime_get(), rps->pm_timestamp);
+}
+
 static u32 rps_pm_mask(struct intel_rps *rps, u8 val)
 {
 	u32 mask = 0;
@@ -742,8 +792,11 @@ void intel_rps_unpark(struct intel_rps *rps)
 
 	mutex_unlock(&rps->lock);
 
+	rps->pm_iir = 0;
 	if (intel_rps_has_interrupts(rps))
 		rps_enable_interrupts(rps);
+	if (intel_rps_uses_timer(rps))
+		rps_start_timer(rps);
 
 	if (IS_GEN(rps_to_i915(rps), 5))
 		gen5_rps_update(rps);
@@ -754,6 +807,8 @@ void intel_rps_park(struct intel_rps *rps)
 	if (!intel_rps_clear_active(rps))
 		return;
 
+	if (intel_rps_uses_timer(rps))
+		rps_stop_timer(rps);
 	if (intel_rps_has_interrupts(rps))
 		rps_disable_interrupts(rps);
 
@@ -1679,6 +1734,7 @@ void intel_rps_init_early(struct intel_rps *rps)
 	mutex_init(&rps->power.mutex);
 
 	INIT_WORK(&rps->work, rps_work);
+	timer_setup(&rps->timer, rps_timer, 0);
 
 	atomic_set(&rps->num_waiters, 0);
 }
@@ -1738,7 +1794,10 @@ void intel_rps_init(struct intel_rps *rps)
 
 	if (INTEL_GEN(i915) >= 6) {
 		rps_disable_interrupts(rps);
-		intel_rps_set_interrupts(rps);
+		if (HAS_EXECLISTS(i915))
+			intel_rps_set_timer(rps);
+		else
+			intel_rps_set_interrupts(rps);
 	}
 }
 
diff --git a/drivers/gpu/drm/i915/gt/intel_rps.h b/drivers/gpu/drm/i915/gt/intel_rps.h
index 8276c4e9d78f..31c2604bcf16 100644
--- a/drivers/gpu/drm/i915/gt/intel_rps.h
+++ b/drivers/gpu/drm/i915/gt/intel_rps.h
@@ -76,4 +76,14 @@ static inline void intel_rps_set_interrupts(struct intel_rps *rps)
 	set_bit(INTEL_RPS_INTERRUPTS, &rps->flags);
 }
 
+static inline bool intel_rps_uses_timer(const struct intel_rps *rps)
+{
+	return test_bit(INTEL_RPS_TIMER, &rps->flags);
+}
+
+static inline void intel_rps_set_timer(struct intel_rps *rps)
+{
+	set_bit(INTEL_RPS_TIMER, &rps->flags);
+}
+
 #endif /* INTEL_RPS_H */
diff --git a/drivers/gpu/drm/i915/gt/intel_rps_types.h b/drivers/gpu/drm/i915/gt/intel_rps_types.h
index 624e93108da4..804e2ccc0ea8 100644
--- a/drivers/gpu/drm/i915/gt/intel_rps_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_rps_types.h
@@ -35,6 +35,7 @@ enum {
 	INTEL_RPS_ENABLED = 0,
 	INTEL_RPS_ACTIVE,
 	INTEL_RPS_INTERRUPTS,
+	INTEL_RPS_TIMER,
 };
 
 struct intel_rps {
@@ -44,8 +45,11 @@ struct intel_rps {
 	 * work, interrupts_enabled and pm_iir are protected by
 	 * dev_priv->irq_lock
 	 */
+	struct timer_list timer;
 	struct work_struct work;
 	unsigned long flags;
+
+	ktime_t pm_timestamp;
 	u32 pm_iir;
 
 	/* PM interrupt bits that should never be masked */
-- 
2.20.1