[Intel-gfx] [PATCH v2 8/9] drm/i915/uc: Stop talking with GuC when resetting

[Michal Wajdeczko]

Knowing that GuC will be reset soon, we may stop all communication
immediately without doing graceful cleanup as it is not needed.

This patch will also help us capture any unwanted/unexpected attempts
to talk with GuC after we decided to reset it. And we need to keep
'disable' part as current and upcoming firmware still expect graceful
cleanup.

v2: update commit msg

Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
---
 drivers/gpu/drm/i915/intel_guc_ct.h |  5 +++++
 drivers/gpu/drm/i915/intel_uc.c     | 13 ++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_guc_ct.h b/drivers/gpu/drm/i915/intel_guc_ct.h
index f5e7f0663304..41ba593a4df7 100644
--- a/drivers/gpu/drm/i915/intel_guc_ct.h
+++ b/drivers/gpu/drm/i915/intel_guc_ct.h
@@ -96,4 +96,9 @@ void intel_guc_ct_fini(struct intel_guc_ct *ct);
 int intel_guc_ct_enable(struct intel_guc_ct *ct);
 void intel_guc_ct_disable(struct intel_guc_ct *ct);
 
+static inline void intel_guc_ct_stop(struct intel_guc_ct *ct)
+{
+	ct->host_channel.enabled = false;
+}
+
 #endif /* _INTEL_GUC_CT_H_ */
diff --git a/drivers/gpu/drm/i915/intel_uc.c b/drivers/gpu/drm/i915/intel_uc.c
index 3d81a512e5c8..f17cb3dad90b 100644
--- a/drivers/gpu/drm/i915/intel_uc.c
+++ b/drivers/gpu/drm/i915/intel_uc.c
@@ -224,6 +224,17 @@ static int guc_enable_communication(struct intel_guc *guc)
 	return 0;
 }
 
+static void guc_stop_communication(struct intel_guc *guc)
+{
+	struct drm_i915_private *i915 = guc_to_i915(guc);
+
+	if (HAS_GUC_CT(i915))
+		intel_guc_ct_stop(&guc->ct);
+
+	guc->send = intel_guc_send_nop;
+	guc->handler = intel_guc_to_host_event_handler_nop;
+}
+
 static void guc_disable_communication(struct intel_guc *guc)
 {
 	struct drm_i915_private *i915 = guc_to_i915(guc);
@@ -485,7 +496,7 @@ void intel_uc_reset_prepare(struct drm_i915_private *i915)
 	if (!USES_GUC(i915))
 		return;
 
-	guc_disable_communication(guc);
+	guc_stop_communication(guc);
 	__uc_sanitize(i915);
 }
 
-- 
2.19.2