[Intel-gfx] [PATCH 12/36] drm/i915/gt: Track if an engine requires forcewake w/a

[Chris Wilson <chris@chris-wilson.co.uk>]

Sometimes an engine might need to keep forcewake active while it is busy
submitting requests for a particular workaround. Track such nuisance
with engine->fw_domain.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gt/intel_engine_types.h   | 9 +++++++++
 drivers/gpu/drm/i915/gt/intel_ring_scheduler.c | 4 ++++
 2 files changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 3782e27c2945..ccdd69923793 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -313,6 +313,15 @@ struct intel_engine_cs {
 	u32 context_size;
 	u32 mmio_base;
 
+	/*
+	 * Some w/a require forcewake to be held (which prevents RC6) while
+	 * a particular engine is active. If so, we set fw_domain to which
+	 * domains need to be held for the duration of request activity,
+	 * and 0 if none.
+	 */
+	unsigned int fw_domain;
+	unsigned int fw_active;
+
 	unsigned long context_tag;
 
 	struct rb_node uabi_node;
diff --git a/drivers/gpu/drm/i915/gt/intel_ring_scheduler.c b/drivers/gpu/drm/i915/gt/intel_ring_scheduler.c
index aaff554865b1..777cab6d9540 100644
--- a/drivers/gpu/drm/i915/gt/intel_ring_scheduler.c
+++ b/drivers/gpu/drm/i915/gt/intel_ring_scheduler.c
@@ -60,6 +60,8 @@ static struct i915_request *
 schedule_in(struct intel_engine_cs *engine, struct i915_request *rq)
 {
 	__intel_gt_pm_get(engine->gt);
+	if (!engine->fw_active++ && engine->fw_domain)
+		intel_uncore_forcewake_get(engine->uncore, engine->fw_domain);
 	intel_engine_context_in(engine);
 	return i915_request_get(rq);
 }
@@ -74,6 +76,8 @@ schedule_out(struct intel_engine_cs *engine, struct i915_request *rq)
 
 	i915_request_put(rq);
 	intel_engine_context_out(engine);
+	if (!--engine->fw_active && engine->fw_domain)
+		intel_uncore_forcewake_put(engine->uncore, engine->fw_domain);
 	intel_gt_pm_put_async(engine->gt);
 }
 
-- 
2.20.1

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