[PATCH v2 12/15] drm/i915/huc: stall media submission until HuC is loaded

[Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>]

Wait on the fence to be signalled to avoid the submissions finding HuC
not yet loaded.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tony Ye <tony.ye@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_huc.h |  6 ++++++
 drivers/gpu/drm/i915/i915_request.c    | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.h b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
index 49374f306a7f..209de60474a5 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_huc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
@@ -77,6 +77,12 @@ static inline bool intel_huc_is_loaded_by_gsc(const struct intel_huc *huc)
 	return huc->fw.loaded_via_gsc;
 }
 
+static inline bool intel_huc_wait_required(struct intel_huc *huc)
+{
+	return intel_huc_is_used(huc) && intel_huc_is_loaded_by_gsc(huc) &&
+	       !intel_huc_is_authenticated(huc);
+}
+
 void intel_huc_load_status(struct intel_huc *huc, struct drm_printer *p);
 
 #endif
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 62fad16a55e8..77f45a3cb01f 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1621,6 +1621,20 @@ i915_request_await_object(struct i915_request *to,
 	return ret;
 }
 
+static void i915_request_await_huc(struct i915_request *rq)
+{
+	struct intel_huc *huc = &rq->context->engine->gt->uc.huc;
+
+	/* don't stall kernel submissions! */
+	if (!rcu_access_pointer(rq->context->gem_context))
+		return;
+
+	if (intel_huc_wait_required(huc))
+		i915_sw_fence_await_sw_fence(&rq->submit,
+					     &huc->delayed_load.fence,
+					     &rq->submitq);
+}
+
 static struct i915_request *
 __i915_request_ensure_parallel_ordering(struct i915_request *rq,
 					struct intel_timeline *timeline)
@@ -1702,6 +1716,16 @@ __i915_request_add_to_timeline(struct i915_request *rq)
 	struct intel_timeline *timeline = i915_request_timeline(rq);
 	struct i915_request *prev;
 
+	/*
+	 * Media workloads may require HuC, so stall them until HuC loading is
+	 * complete. Note that HuC not being loaded when a user submission
+	 * arrives can only happen when HuC is loaded via GSC and in that case
+	 * we still expect the window between us starting to accept submissions
+	 * and HuC loading completion to be small (a few hundred ms).
+	 */
+	if (rq->engine->class == VIDEO_DECODE_CLASS)
+		i915_request_await_huc(rq);
+
 	/*
 	 * Dependency tracking and request ordering along the timeline
 	 * is special cased so that we can eliminate redundant ordering
-- 
2.37.2