drm/i915: Consolidate checks for engine stats availability

Sagar noticed the check can be consolidated between the engine stats
implementation and the PMU.

My first choice was a static inline helper but that got into include
ordering mess quickly fast so I went with a macro instead. At some point
we should perhaps looking into taking out the non-ringubffer bits from
intel_ringbuffer.h into a new intel_engine.h or something.

v2: Use engine->flags. (Chris Wilson)
v3: Rebase and mark GuC as not yet supported. (Chris Wilson)
v4: Move flag setting to intel_engines_reset_default_submission.
    (Chris Wilson)
v5: Move flag setting to logical_ring_setup.
v6: intel_engines_reset_default_submission is the wrong place to set the
    flag - it needs to be in execlists_set_default_submission. (Sagar)
v7: Flag setting in logical_ring_setup is not required. (Chris)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Suggested-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com> (v6)
Link: https://patchwork.freedesktop.org/patch/msgid/20171129102805.22690-1-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_pmu.c

@@ -90,11 +90,6 @@ static unsigned int event_enabled_bit(struct perf_event *event)
 	return config_enabled_bit(event->attr.config);
 }
 
-static bool supports_busy_stats(struct drm_i915_private *i915)
-{
-	return INTEL_GEN(i915) >= 8;
-}
-
 static bool pmu_needs_timer(struct drm_i915_private *i915, bool gpu_active)
 {
 	u64 enable;
@@ -123,8 +118,10 @@ static bool pmu_needs_timer(struct drm_i915_private *i915, bool gpu_active)
 	/*
 	 * Also there is software busyness tracking available we do not
 	 * need the timer for I915_SAMPLE_BUSY counter.
+	 *
+	 * Use RCS as proxy for all engines.
 	 */
-	else if (supports_busy_stats(i915))
+	else if (intel_engine_supports_stats(i915->engine[RCS]))
 		enable &= ~BIT(I915_SAMPLE_BUSY);
 
 	/*
@@ -447,7 +444,7 @@ again:
 
 static bool engine_needs_busy_stats(struct intel_engine_cs *engine)
 {
-	return supports_busy_stats(engine->i915) &&
+	return intel_engine_supports_stats(engine) &&
 	       (engine->pmu.enable & BIT(I915_SAMPLE_BUSY));
 }
 

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -1863,7 +1863,7 @@ int intel_enable_engine_stats(struct intel_engine_cs *engine)
 {
 	unsigned long flags;
 
-	if (INTEL_GEN(engine->i915) < 8)
+	if (!intel_engine_supports_stats(engine))
 		return -ENODEV;
 
 	spin_lock_irqsave(&engine->stats.lock, flags);
@@ -1924,7 +1924,7 @@ void intel_disable_engine_stats(struct intel_engine_cs *engine)
 {
 	unsigned long flags;
 
-	if (INTEL_GEN(engine->i915) < 8)
+	if (!intel_engine_supports_stats(engine))
 		return;
 
 	spin_lock_irqsave(&engine->stats.lock, flags);

drivers/gpu/drm/i915/intel_guc_submission.c

@@ -1453,6 +1453,8 @@ int intel_guc_submission_enable(struct intel_guc *guc)
 		execlists->tasklet.func = guc_submission_tasklet;
 		engine->park = guc_submission_park;
 		engine->unpark = guc_submission_unpark;
+
+		engine->flags &= ~I915_ENGINE_SUPPORTS_STATS;
 	}
 
 	return 0;

drivers/gpu/drm/i915/intel_lrc.c

@@ -1919,6 +1919,8 @@ static void execlists_set_default_submission(struct intel_engine_cs *engine)
 
 	engine->park = NULL;
 	engine->unpark = NULL;
+
+	engine->flags |= I915_ENGINE_SUPPORTS_STATS;
 }
 
 static void

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -539,6 +539,7 @@ struct intel_engine_cs {
 	struct intel_engine_hangcheck hangcheck;
 
 #define I915_ENGINE_NEEDS_CMD_PARSER BIT(0)
+#define I915_ENGINE_SUPPORTS_STATS   BIT(1)
 	unsigned int flags;
 
 	/*
@@ -603,6 +604,11 @@ static inline bool intel_engine_needs_cmd_parser(struct intel_engine_cs *engine)
 	return engine->flags & I915_ENGINE_NEEDS_CMD_PARSER;
 }
 
+static inline bool intel_engine_supports_stats(struct intel_engine_cs *engine)
+{
+	return engine->flags & I915_ENGINE_SUPPORTS_STATS;
+}
+
 static inline void
 execlists_set_active(struct intel_engine_execlists *execlists,
 		     unsigned int bit)