drm/i915/guc: Make intel_guc_send a function pointer

Prepare for an alternate GuC communication interface.

v2: Make a few functions static and name them correctly while we are at it (Oscar), but
leave an intel_guc_send_mmio interface for users that require old-style communication.

v3: Send intel_uc_init_early back to the top (Michal).
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/intel_uc.c

@@ -83,7 +83,10 @@ void intel_uc_sanitize_options(struct drm_i915_private *dev_priv)
 
 void intel_uc_init_early(struct drm_i915_private *dev_priv)
 {
-	mutex_init(&dev_priv->guc.send_mutex);
+	struct intel_guc *guc = &dev_priv->guc;
+
+	mutex_init(&guc->send_mutex);
+	guc->send = intel_guc_send_mmio;
 }
 
 void intel_uc_init_fw(struct drm_i915_private *dev_priv)
@@ -216,7 +219,7 @@ void intel_uc_fini_hw(struct drm_i915_private *dev_priv)
  * Read GuC command/status register (SOFT_SCRATCH_0)
  * Return true if it contains a response rather than a command
  */
-static bool intel_guc_recv(struct intel_guc *guc, u32 *status)
+static bool guc_recv(struct intel_guc *guc, u32 *status)
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
 
@@ -225,7 +228,10 @@ static bool intel_guc_recv(struct intel_guc *guc, u32 *status)
 	return INTEL_GUC_RECV_IS_RESPONSE(val);
 }
 
-int intel_guc_send(struct intel_guc *guc, const u32 *action, u32 len)
+/*
+ * This function implements the MMIO based host to GuC interface.
+ */
+int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len)
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
 	u32 status;
@@ -253,9 +259,9 @@ int intel_guc_send(struct intel_guc *guc, const u32 *action, u32 len)
 	 * up to that length of time, then switch to a slower sleep-wait loop.
 	 * No inte_guc_send command should ever take longer than 10ms.
 	 */
-	ret = wait_for_us(intel_guc_recv(guc, &status), 10);
+	ret = wait_for_us(guc_recv(guc, &status), 10);
 	if (ret)
-		ret = wait_for(intel_guc_recv(guc, &status), 10);
+		ret = wait_for(guc_recv(guc, &status), 10);
 	if (status != INTEL_GUC_STATUS_SUCCESS) {
 		/*
 		 * Either the GuC explicitly returned an error (which

drivers/gpu/drm/i915/intel_uc.h

@@ -176,6 +176,9 @@ 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);
 };
 
 struct intel_huc {
@@ -194,8 +197,12 @@ int intel_uc_init_hw(struct drm_i915_private *dev_priv);
 void intel_uc_fini_hw(struct drm_i915_private *dev_priv);
 void intel_uc_prepare_fw(struct drm_i915_private *dev_priv,
 			 struct intel_uc_fw *uc_fw);
-int intel_guc_send(struct intel_guc *guc, const u32 *action, u32 len);
 int intel_guc_sample_forcewake(struct intel_guc *guc);
+int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len);
+static inline int intel_guc_send(struct intel_guc *guc, const u32 *action, u32 len)
+{
+	return guc->send(guc, action, len);
+}
 
 /* intel_guc_loader.c */
 int intel_guc_select_fw(struct intel_guc *guc);