drm/i915/guc: Remove function pointers for send/receive calls

Since we started using CT buffers on all gens, the function pointers can
only be set to either the _nop() or the _ct() functions. Since the
_nop() case applies to when the CT are disabled, we can just handle that
case in the _ct() functions and call them directly.

v2: keep intel_guc_send() and make the CT send/receive functions work on
    intel_guc_ct. (Michal)

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191217012316.13271-5-daniele.ceraolospurio@intel.com

drivers/gpu/drm/i915/gt/uc/intel_guc.c

@@ -177,8 +177,6 @@ void intel_guc_init_early(struct intel_guc *guc)
 
 	mutex_init(&guc->send_mutex);
 	spin_lock_init(&guc->irq_lock);
-	guc->send = intel_guc_send_nop;
-	guc->handler = intel_guc_to_host_event_handler_nop;
 	if (INTEL_GEN(i915) >= 11) {
 		guc->notify = gen11_guc_raise_irq;
 		guc->interrupts.reset = gen11_reset_guc_interrupts;
@@ -403,18 +401,6 @@ void intel_guc_fini(struct intel_guc *guc)
 	intel_uc_fw_cleanup_fetch(&guc->fw);
 }
 
-int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len,
-		       u32 *response_buf, u32 response_buf_size)
-{
-	WARN(1, "Unexpected send: action=%#x\n", *action);
-	return -ENODEV;
-}
-
-void intel_guc_to_host_event_handler_nop(struct intel_guc *guc)
-{
-	WARN(1, "Unexpected event: no suitable handler\n");
-}
-
 /*
  * This function implements the MMIO based host to GuC interface.
  */

drivers/gpu/drm/i915/gt/uc/intel_guc.h

@@ -70,13 +70,6 @@ struct intel_guc {
 	/* To serialize the intel_guc_send actions */
 	struct mutex send_mutex;
 
-	/* GuC's FW specific send function */
-	int (*send)(struct intel_guc *guc, const u32 *data, u32 len,
-		    u32 *response_buf, u32 response_buf_size);
-
-	/* GuC's FW specific event handler function */
-	void (*handler)(struct intel_guc *guc);
-
 	/* GuC's FW specific notify function */
 	void (*notify)(struct intel_guc *guc);
 };
@@ -84,14 +77,15 @@ struct intel_guc {
 static
 inline int intel_guc_send(struct intel_guc *guc, const u32 *action, u32 len)
 {
-	return guc->send(guc, action, len, NULL, 0);
+	return intel_guc_ct_send(&guc->ct, action, len, NULL, 0);
 }
 
 static inline int
 intel_guc_send_and_receive(struct intel_guc *guc, const u32 *action, u32 len,
 			   u32 *response_buf, u32 response_buf_size)
 {
-	return guc->send(guc, action, len, response_buf, response_buf_size);
+	return intel_guc_ct_send(&guc->ct, action, len,
+				 response_buf, response_buf_size);
 }
 
 static inline void intel_guc_notify(struct intel_guc *guc)
@@ -101,7 +95,7 @@ static inline void intel_guc_notify(struct intel_guc *guc)
 
 static inline void intel_guc_to_host_event_handler(struct intel_guc *guc)
 {
-	guc->handler(guc);
+	intel_guc_ct_event_handler(&guc->ct);
 }
 
 /* GuC addresses above GUC_GGTT_TOP also don't map through the GTT */
@@ -136,12 +130,8 @@ void intel_guc_init_send_regs(struct intel_guc *guc);
 void intel_guc_write_params(struct intel_guc *guc);
 int intel_guc_init(struct intel_guc *guc);
 void intel_guc_fini(struct intel_guc *guc);
-int intel_guc_send_nop(struct intel_guc *guc, const u32 *action, u32 len,
-		       u32 *response_buf, u32 response_buf_size);
 int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len,
 			u32 *response_buf, u32 response_buf_size);
-void intel_guc_to_host_event_handler(struct intel_guc *guc);
-void intel_guc_to_host_event_handler_nop(struct intel_guc *guc);
 int intel_guc_to_host_process_recv_msg(struct intel_guc *guc,
 				       const u32 *payload, u32 len);
 int intel_guc_sample_forcewake(struct intel_guc *guc);

drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c

@@ -510,13 +510,18 @@ unlink:
 /*
  * Command Transport (CT) buffer based GuC send function.
  */
-int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len,
+int intel_guc_ct_send(struct intel_guc_ct *ct, const u32 *action, u32 len,
 		      u32 *response_buf, u32 response_buf_size)
 {
-	struct intel_guc_ct *ct = &guc->ct;
+	struct intel_guc *guc = ct_to_guc(ct);
 	u32 status = ~0; /* undefined */
 	int ret;
 
+	if (unlikely(!ct->enabled)) {
+		WARN(1, "Unexpected send: action=%#x\n", *action);
+		return -ENODEV;
+	}
+
 	mutex_lock(&guc->send_mutex);
 
 	ret = ct_send(ct, action, len, response_buf, response_buf_size, &status);
@@ -787,15 +792,16 @@ static int ct_handle_request(struct intel_guc_ct *ct, const u32 *msg)
  * When we're communicating with the GuC over CT, GuC uses events
  * to notify us about new messages being posted on the RECV buffer.
  */
-void intel_guc_to_host_event_handler_ct(struct intel_guc *guc)
+void intel_guc_ct_event_handler(struct intel_guc_ct *ct)
 {
-	struct intel_guc_ct *ct = &guc->ct;
 	struct intel_guc_ct_buffer *ctb = &ct->ctbs[CTB_RECV];
 	u32 msg[GUC_CT_MSG_LEN_MASK + 1]; /* one extra dw for the header */
 	int err = 0;
 
-	if (!ct->enabled)
+	if (unlikely(!ct->enabled)) {
+		WARN(1, "Unexpected GuC event received while CT disabled!\n");
 		return;
+	}
 
 	do {
 		err = ctb_read(ctb, msg);

drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h

@@ -65,8 +65,13 @@ 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);
 
-int intel_guc_send_ct(struct intel_guc *guc, const u32 *action, u32 len,
+static inline bool intel_guc_ct_enabled(struct intel_guc_ct *ct)
+{
+	return ct->enabled;
+}
+
+int intel_guc_ct_send(struct intel_guc_ct *ct, const u32 *action, u32 len,
 		      u32 *response_buf, u32 response_buf_size);
-void intel_guc_to_host_event_handler_ct(struct intel_guc *guc);
+void intel_guc_ct_event_handler(struct intel_guc_ct *ct);
 
 #endif /* _INTEL_GUC_CT_H_ */

drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c

@@ -43,7 +43,6 @@
  * Firmware writes a success/fail code back to the action register after
  * processes the request. The kernel driver polls waiting for this update and
  * then proceeds.
- * See intel_guc_send()
  *
  * Work Items:
  * There are several types of work items that the host may place into a

drivers/gpu/drm/i915/gt/uc/intel_uc.c

@@ -123,6 +123,11 @@ static void __uc_free_load_err_log(struct intel_uc *uc)
 		i915_gem_object_put(log);
 }
 
+static inline bool guc_communication_enabled(struct intel_guc *guc)
+{
+	return intel_guc_ct_enabled(&guc->ct);
+}
+
 /*
  * Events triggered while CT buffers are disabled are logged in the SCRATCH_15
  * register using the same bits used in the CT message payload. Since our
@@ -158,7 +163,7 @@ static void guc_handle_mmio_msg(struct intel_guc *guc)
 	struct drm_i915_private *i915 = guc_to_gt(guc)->i915;
 
 	/* we need communication to be enabled to reply to GuC */
-	GEM_BUG_ON(guc->handler == intel_guc_to_host_event_handler_nop);
+	GEM_BUG_ON(!guc_communication_enabled(guc));
 
 	if (!guc->mmio_msg)
 		return;
@@ -185,11 +190,6 @@ static void guc_disable_interrupts(struct intel_guc *guc)
 	guc->interrupts.disable(guc);
 }
 
-static inline bool guc_communication_enabled(struct intel_guc *guc)
-{
-	return guc->send != intel_guc_send_nop;
-}
-
 static int guc_enable_communication(struct intel_guc *guc)
 {
 	struct drm_i915_private *i915 = guc_to_gt(guc)->i915;
@@ -205,9 +205,6 @@ static int guc_enable_communication(struct intel_guc *guc)
 	if (ret)
 		return ret;
 
-	guc->send = intel_guc_send_ct;
-	guc->handler = intel_guc_to_host_event_handler_ct;
-
 	/* check for mmio messages received before/during the CT enable */
 	guc_get_mmio_msg(guc);
 	guc_handle_mmio_msg(guc);
@@ -216,7 +213,7 @@ static int guc_enable_communication(struct intel_guc *guc)
 
 	/* check for CT messages received before we enabled interrupts */
 	spin_lock_irq(&i915->irq_lock);
-	intel_guc_to_host_event_handler_ct(guc);
+	intel_guc_ct_event_handler(&guc->ct);
 	spin_unlock_irq(&i915->irq_lock);
 
 	DRM_INFO("GuC communication enabled\n");
@@ -235,9 +232,6 @@ static void guc_disable_communication(struct intel_guc *guc)
 
 	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);
 
 	/*