[PATCH 25/28] drm/i915/guc: New engine-reset-complete message

[Michal Wajdeczko]

GuC sends ENGINE_RESET_COMPLETE message as an follow-up answer
to earlier ENGINE_RESET request from the host. Once this message
is received, clear engine reset flag to unblock our reset process.

Credits-to: Michel Thierry <michel.thierry at intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
Cc: Michal Winiarski <michal.winiarski at intel.com>
Cc: Tomasz Lis <tomasz.lis at intel.com>
---
 drivers/gpu/drm/i915/intel_guc.c      | 29 +++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_guc_fwif.h |  3 ++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_guc.c b/drivers/gpu/drm/i915/intel_guc.c
index abedb8982040..c9fbda2e8a78 100644
--- a/drivers/gpu/drm/i915/intel_guc.c
+++ b/drivers/gpu/drm/i915/intel_guc.c
@@ -27,6 +27,9 @@
 #include "intel_guc_submission.h"
 #include "i915_drv.h"
 
+static void guc_handle_engine_reset_completed(struct intel_guc *guc,
+					      const u32 engine_class);
+
 static void gen8_guc_raise_irq(struct intel_guc *guc)
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
@@ -517,6 +520,12 @@ int intel_guc_to_host_process_recv_msg(struct intel_guc *guc,
 		   INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED))
 		intel_guc_log_handle_flush_event(&guc->log);
 
+	if (msg & INTEL_GUC_RECV_MSG_ENGINE_RESET_COMPLETE) {
+		if (len != 3)
+			return -EPROTO;
+		guc_handle_engine_reset_completed(guc, payload[1]);
+	}
+
 	return 0;
 }
 
@@ -615,6 +624,7 @@ guc_set_class_under_reset(struct intel_guc *guc, unsigned int guc_class)
 {
 	GEM_BUG_ON(guc_class >= GUC_MAX_ENGINE_CLASSES);
 	guc->engine_class_under_reset |= BIT(guc_class);
+	intel_guc_enable_msg(guc, INTEL_GUC_RECV_MSG_ENGINE_RESET_COMPLETE);
 }
 
 static inline void
@@ -622,6 +632,7 @@ guc_clear_class_under_reset(struct intel_guc *guc, unsigned int guc_class)
 {
 	GEM_BUG_ON(guc_class >= GUC_MAX_ENGINE_CLASSES);
 	guc->engine_class_under_reset &= ~BIT(guc_class);
+	intel_guc_disable_msg(guc, INTEL_GUC_RECV_MSG_ENGINE_RESET_COMPLETE);
 }
 
 static inline bool
@@ -686,6 +697,24 @@ int intel_guc_reset_engine(struct intel_guc *guc,
 	return ret;
 }
 
+/*
+ * GuC notifies host that reset engine has completed.
+ * This message should only be received after a request-reset h2g,
+ * so check that and clear the engine_class_under_reset flag.
+ */
+static void guc_handle_engine_reset_completed(struct intel_guc *guc,
+					      const u32 engine_class)
+{
+	if (engine_class >= GUC_MAX_ENGINE_CLASSES ||
+	    !guc_is_class_under_reset(guc, engine_class)) {
+		DRM_WARN("Unexpected reset-complete for engine class: %d",
+			 engine_class);
+		return;
+	}
+
+	guc_clear_class_under_reset(guc, engine_class);
+}
+
 /**
  * intel_guc_resume() - notify GuC resuming from suspend state
  * @guc:	the guc
diff --git a/drivers/gpu/drm/i915/intel_guc_fwif.h b/drivers/gpu/drm/i915/intel_guc_fwif.h
index 004d3d882f6f..3b037a9e3181 100644
--- a/drivers/gpu/drm/i915/intel_guc_fwif.h
+++ b/drivers/gpu/drm/i915/intel_guc_fwif.h
@@ -722,7 +722,8 @@ enum intel_guc_response_status {
 /* This action will be programmed in C1BC - SOFT_SCRATCH_15_REG */
 enum intel_guc_recv_message {
 	INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED = BIT(1),
-	INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER = BIT(3)
+	INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER = BIT(3),
+	INTEL_GUC_RECV_MSG_ENGINE_RESET_COMPLETE = BIT(25),
 };
 
 #endif
-- 
2.19.2