[Intel-gfx] [PATCH v2 1/2] drm/i915/guc: reorder enable/disable communication steps

[Daniele Ceraolo Spurio]

Make sure we always have CT buffers enabled when the interrupts are
enabled, so we can always handle interrupts from GuC. Also move the
setting of the guc->send and guc->handler functions to the GuC
communication control functions for consistency.

The reorder also fixes the onion unwinding of intel_uc_init_hw, because
guc_enable_communication would've left interrupts enabled when failing
to enable CTB.

v2: always retunr the result of ctch_enable() in
    intel_guc_ct_enable() (Michal)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110943
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
Reviewed-by: Matthew Brost <matthew.brost at intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
---
 drivers/gpu/drm/i915/intel_guc_ct.c | 22 ++++------------------
 drivers/gpu/drm/i915/intel_guc_ct.h |  4 ++++
 drivers/gpu/drm/i915/intel_uc.c     | 19 ++++++++++++++++---
 3 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_guc_ct.c b/drivers/gpu/drm/i915/intel_guc_ct.c
index 3921809f812b..9e383a47609f 100644
--- a/drivers/gpu/drm/i915/intel_guc_ct.c
+++ b/drivers/gpu/drm/i915/intel_guc_ct.c
@@ -529,8 +529,8 @@ static int ctch_send(struct intel_guc_ct *ct,
 /*
  * Command Transport (CT) buffer based GuC send function.
  */
-static int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len,
-			     u32 *response_buf, u32 response_buf_size)
+int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len,
+		      u32 *response_buf, u32 response_buf_size)
 {
 	struct intel_guc_ct *ct = &guc->ct;
 	struct intel_guc_ct_channel *ctch = &ct->host_channel;
@@ -834,7 +834,7 @@ static void ct_process_host_channel(struct intel_guc_ct *ct)
  * When we're communicating with the GuC over CT, GuC uses events
  * to notify us about new messages being posted on the RECV buffer.
  */
-static void intel_guc_to_host_event_handler_ct(struct intel_guc *guc)
+void intel_guc_to_host_event_handler_ct(struct intel_guc *guc)
 {
 	struct intel_guc_ct *ct = &guc->ct;
 
@@ -892,20 +892,11 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct)
 {
 	struct intel_guc *guc = ct_to_guc(ct);
 	struct intel_guc_ct_channel *ctch = &ct->host_channel;
-	int err;
 
 	if (ctch->enabled)
 		return 0;
 
-	err = ctch_enable(guc, ctch);
-	if (unlikely(err))
-		return err;
-
-	/* Switch into cmd transport buffer based send() */
-	guc->send = intel_guc_send_ct;
-	guc->handler = intel_guc_to_host_event_handler_ct;
-	DRM_INFO("CT: %s\n", enableddisabled(true));
-	return 0;
+	return ctch_enable(guc, ctch);
 }
 
 /**
@@ -921,9 +912,4 @@ void intel_guc_ct_disable(struct intel_guc_ct *ct)
 		return;
 
 	ctch_disable(guc, ctch);
-
-	/* Disable send */
-	guc->send = intel_guc_send_nop;
-	guc->handler = intel_guc_to_host_event_handler_nop;
-	DRM_INFO("CT: %s\n", enableddisabled(false));
 }
diff --git a/drivers/gpu/drm/i915/intel_guc_ct.h b/drivers/gpu/drm/i915/intel_guc_ct.h
index 41ba593a4df7..0ec17493d83b 100644
--- a/drivers/gpu/drm/i915/intel_guc_ct.h
+++ b/drivers/gpu/drm/i915/intel_guc_ct.h
@@ -101,4 +101,8 @@ static inline void intel_guc_ct_stop(struct intel_guc_ct *ct)
 	ct->host_channel.enabled = false;
 }
 
+int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len,
+		      u32 *response_buf, u32 response_buf_size);
+void intel_guc_to_host_event_handler_ct(struct intel_guc *guc);
+
 #endif /* _INTEL_GUC_CT_H_ */
diff --git a/drivers/gpu/drm/i915/intel_uc.c b/drivers/gpu/drm/i915/intel_uc.c
index ae45651ac73c..c7f82c944dd6 100644
--- a/drivers/gpu/drm/i915/intel_uc.c
+++ b/drivers/gpu/drm/i915/intel_uc.c
@@ -235,9 +235,20 @@ static void guc_disable_interrupts(struct intel_guc *guc)
 
 static int guc_enable_communication(struct intel_guc *guc)
 {
+	int ret;
+
+	ret = intel_guc_ct_enable(&guc->ct);
+	if (ret)
+		return ret;
+
+	guc->send = intel_guc_send_ct;
+	guc->handler = intel_guc_to_host_event_handler_ct;
+
 	guc_enable_interrupts(guc);
 
-	return intel_guc_ct_enable(&guc->ct);
+	DRM_INFO("GuC communication enabled\n");
+
+	return 0;
 }
 
 static void guc_stop_communication(struct intel_guc *guc)
@@ -250,12 +261,14 @@ static void guc_stop_communication(struct intel_guc *guc)
 
 static void guc_disable_communication(struct intel_guc *guc)
 {
-	intel_guc_ct_disable(&guc->ct);
-
 	guc_disable_interrupts(guc);
 
 	guc->send = intel_guc_send_nop;
 	guc->handler = intel_guc_to_host_event_handler_nop;
+
+	intel_guc_ct_disable(&guc->ct);
+
+	DRM_INFO("GuC communication disabled\n");
 }
 
 int intel_uc_init_misc(struct drm_i915_private *i915)
-- 
2.20.1