drm/xe: Split GuC communication initialization

Soon we will be trying to communicate with the GuC firmware very
early during VF driver probe, before we finish normal init steps.
Split GuC communication initialization code so the GuC MMIO based
communication xe_guc_mmio_send() functions will work where needed.

Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20240111162051.585-1-michal.wajdeczko@intel.comSigned-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>

drivers/gpu/drm/xe/xe_guc.c

@@ -243,6 +243,22 @@ static void guc_fini(struct drm_device *drm, void *arg)
 	xe_force_wake_put(gt_to_fw(guc_to_gt(guc)), XE_FORCEWAKE_ALL);
 }
 
+/**
+ * xe_guc_comm_init_early - early initialization of GuC communication
+ * @guc: the &xe_guc to initialize
+ *
+ * Must be called prior to first MMIO communication with GuC firmware.
+ */
+void xe_guc_comm_init_early(struct xe_guc *guc)
+{
+	struct xe_gt *gt = guc_to_gt(guc);
+
+	if (xe_gt_is_media_type(gt))
+		guc->notify_reg = MED_GUC_HOST_INTERRUPT;
+	else
+		guc->notify_reg = GUC_HOST_INTERRUPT;
+}
+
 int xe_guc_init(struct xe_guc *guc)
 {
 	struct xe_device *xe = guc_to_xe(guc);
@@ -283,10 +299,7 @@ int xe_guc_init(struct xe_guc *guc)
 
 	guc_init_params(guc);
 
-	if (xe_gt_is_media_type(gt))
-		guc->notify_reg = MED_GUC_HOST_INTERRUPT;
-	else
-		guc->notify_reg = GUC_HOST_INTERRUPT;
+	xe_guc_comm_init_early(guc);
 
 	xe_uc_fw_change_status(&guc->fw, XE_UC_FIRMWARE_LOADABLE);
 

drivers/gpu/drm/xe/xe_guc.h

@@ -13,6 +13,7 @@
 
 struct drm_printer;
 
+void xe_guc_comm_init_early(struct xe_guc *guc);
 int xe_guc_init(struct xe_guc *guc);
 int xe_guc_init_post_hwconfig(struct xe_guc *guc);
 int xe_guc_post_load_init(struct xe_guc *guc);