[PATCH 1/4] drm/i915/guc: Separate GuC doorbell destroy function into doorbell unit and GuC task

[Sagar Arun Kamble]

Releasing GuC doorbell involves stopping the doorbell unit snooping and
executing doorbell deallocation flow in GuC firmware. When GuC is in sane
state, both steps will be necessary to release doorbell.
If GuC is hung (possibly leading to i915 reset), only doorbell unit
snooping is to be stopped. destroy_doorbell will be called in suspend and
reset flows differently in upcoming patches.

Signed-off-by: Sagar Arun Kamble <sagar.a.kamble at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski at intel.com>
Cc: Michel Thierry <michel.thierry at intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_guc_submission.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index d14c134..b6486dc 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -207,7 +207,7 @@ static int __create_doorbell(struct i915_guc_client *client)
 	return err;
 }
 
-static int __destroy_doorbell(struct i915_guc_client *client)
+static int __destroy_doorbell(struct i915_guc_client *client, bool notify_guc)
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(client->guc);
 	struct guc_doorbell_info *doorbell;
@@ -225,7 +225,10 @@ static int __destroy_doorbell(struct i915_guc_client *client)
 	if (wait_for_us(!(I915_READ(GEN8_DRBREGL(db_id)) & GEN8_DRB_VALID), 10))
 		WARN_ONCE(true, "Doorbell never became invalid after disable\n");
 
-	return __guc_deallocate_doorbell(client->guc, client->stage_id);
+	if (notify_guc)
+		return __guc_deallocate_doorbell(client->guc, client->stage_id);
+
+	return 0;
 }
 
 static int create_doorbell(struct i915_guc_client *client)
@@ -250,7 +253,11 @@ static int create_doorbell(struct i915_guc_client *client)
 	return ret;
 }
 
-static int destroy_doorbell(struct i915_guc_client *client)
+/*
+ * This function deactivates doorbell monitoring through doorbell unit and
+ * optionally notifies GuC to deallocate the doorbell.
+ */
+static int destroy_doorbell(struct i915_guc_client *client, bool notify_guc)
 {
 	int err;
 
@@ -259,7 +266,7 @@ static int destroy_doorbell(struct i915_guc_client *client)
 	/* XXX: wait for any interrupts */
 	/* XXX: wait for workqueue to drain */
 
-	err = __destroy_doorbell(client);
+	err = __destroy_doorbell(client, notify_guc);
 	if (err)
 		return err;
 
@@ -873,7 +880,7 @@ static int __reset_doorbell(struct i915_guc_client* client, u16 db_id)
 	__update_doorbell_desc(client, db_id);
 	err = __create_doorbell(client);
 	if (!err)
-		err = __destroy_doorbell(client);
+		err = __destroy_doorbell(client, true);
 
 	return err;
 }
@@ -899,7 +906,7 @@ static int guc_init_doorbell_hw(struct intel_guc *guc)
 
 		if (has_doorbell(client)) {
 			/* Borrow execbuf_client (we will recreate it later) */
-			destroy_doorbell(client);
+			destroy_doorbell(client, true);
 			recreate_first_client = true;
 		}
 
@@ -925,7 +932,7 @@ static int guc_init_doorbell_hw(struct intel_guc *guc)
 
 	ret = __create_doorbell(guc->preempt_client);
 	if (ret) {
-		__destroy_doorbell(guc->execbuf_client);
+		__destroy_doorbell(guc->execbuf_client, true);
 		return ret;
 	}
 
@@ -1043,7 +1050,7 @@ static void guc_client_free(struct i915_guc_client *client)
 	/* FIXME: in many cases, by the time we get here the GuC has been
 	 * reset, so we cannot destroy the doorbell properly. Ignore the
 	 * error message for now */
-	destroy_doorbell(client);
+	destroy_doorbell(client, true);
 	guc_stage_desc_fini(client->guc, client);
 	i915_gem_object_unpin_map(client->vma->obj);
 	i915_vma_unpin_and_release(&client->vma);
-- 
1.9.1