drm/i915/guc: disable GuC submission earlier during GuC (re)load

When resetting and reloading the GuC, the GuC submission management code
also needs to destroy and recreate the GuC client(s). Currently this is
done by a separate call from the GuC loader, but really, it's just an
internal detail of the submission code. So here we remove the call from
the loader (which is too late, really, because the GuC has already been
reloaded at this point) and put it into guc_submission_init() instead.
This means that any preexisting client is destroyed *before* the GuC
(re)load and then recreated after, iff the firmware was successfully
loaded. If the GuC reload fails, we don't recreate the client, so
fallback to execlists mode (if active) won't leak the client object
(previously, the now-unusable client would have been left allocated,
and leaked if the driver were unloaded).

Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

drivers/gpu/drm/i915/i915_guc_submission.c

@@ -657,17 +657,20 @@ static void guc_client_free(struct drm_device *dev,
 	 */
 
 	if (client->client_base) {
+		uint16_t db_id = client->doorbell_id;
+
 		/*
 		 * If we got as far as setting up a doorbell, make sure
 		 * we shut it down before unmapping & deallocating the
 		 * memory. So first disable the doorbell, then tell the
 		 * GuC that we've finished with it, finally deallocate
 		 * it in our bitmap
 		 */
-		if (client->doorbell_id != GUC_INVALID_DOORBELL_ID) {
+		if (db_id != GUC_INVALID_DOORBELL_ID) {
 			guc_disable_doorbell(guc, client);
-			host2guc_release_doorbell(guc, client);
-			release_doorbell(guc, client->doorbell_id);
+			if (test_bit(db_id, guc->doorbell_bitmap))
+				host2guc_release_doorbell(guc, client);
+			release_doorbell(guc, db_id);
 		}
 
 		kunmap(kmap_to_page(client->client_base));
@@ -912,6 +915,10 @@ int i915_guc_submission_init(struct drm_device *dev)
 	const size_t gemsize = round_up(poolsize, PAGE_SIZE);
 	struct intel_guc *guc = &dev_priv->guc;
 
+	/* Wipe bitmap & delete client in case of reinitialisation */
+	bitmap_clear(guc->doorbell_bitmap, 0, GUC_MAX_DOORBELLS);
+	i915_guc_submission_disable(dev);
+
 	if (!i915.enable_guc_submission)
 		return 0; /* not enabled  */
 
@@ -923,9 +930,7 @@ int i915_guc_submission_init(struct drm_device *dev)
 		return -ENOMEM;
 
 	ida_init(&guc->ctx_ids);
-
 	guc_create_log(guc);
-
 	guc_create_ads(guc);
 
 	return 0;

drivers/gpu/drm/i915/intel_guc_loader.c

@@ -492,9 +492,6 @@ int intel_guc_setup(struct drm_device *dev)
 		intel_guc_fw_status_repr(guc_fw->guc_fw_load_status));
 
 	if (i915.enable_guc_submission) {
-		/* The execbuf_client will be recreated. Release it first. */
-		i915_guc_submission_disable(dev);
-
 		err = i915_guc_submission_enable(dev);
 		if (err)
 			goto fail;