drm/i915: Refactor common ringbuffer allocation code

A small, very small, step to sharing the duplicate code between
execlists and legacy submission engines, starting with the ringbuffer
allocation code.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Arun Siluvery <arun.siluvery@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_lrc.c

@@ -2340,8 +2340,7 @@ void intel_lr_context_free(struct intel_context *ctx)
 				i915_gem_object_ggtt_unpin(ctx_obj);
 			}
 			WARN_ON(ctx->engine[ring->id].pin_count);
-			intel_destroy_ringbuffer_obj(ringbuf);
-			kfree(ringbuf);
+			intel_ringbuffer_free(ringbuf);
 			drm_gem_object_unreference(&ctx_obj->base);
 		}
 	}
@@ -2442,44 +2441,22 @@ int intel_lr_context_deferred_create(struct intel_context *ctx,
 			I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
 	}
 
-	ringbuf = kzalloc(sizeof(*ringbuf), GFP_KERNEL);
-	if (!ringbuf) {
-		DRM_DEBUG_DRIVER("Failed to allocate ringbuffer %s\n",
-				ring->name);
-		ret = -ENOMEM;
+	ringbuf = intel_engine_create_ringbuffer(ring, 4 * PAGE_SIZE);
+	if (IS_ERR(ringbuf)) {
+		ret = PTR_ERR(ringbuf);
 		goto error_unpin_ctx;
 	}
 
-	ringbuf->ring = ring;
-
-	ringbuf->size = 4 * PAGE_SIZE;
-	ringbuf->effective_size = ringbuf->size;
-	ringbuf->head = 0;
-	ringbuf->tail = 0;
-	ringbuf->last_retired_head = -1;
-	intel_ring_update_space(ringbuf);
-
-	if (ringbuf->obj == NULL) {
-		ret = intel_alloc_ringbuffer_obj(dev, ringbuf);
-		if (ret) {
-			DRM_DEBUG_DRIVER(
-				"Failed to allocate ringbuffer obj %s: %d\n",
-				ring->name, ret);
-			goto error_free_rbuf;
-		}
-
 	if (is_global_default_ctx) {
 		ret = intel_pin_and_map_ringbuffer_obj(dev, ringbuf);
 		if (ret) {
 			DRM_ERROR(
 				  "Failed to pin and map ringbuffer %s: %d\n",
 				  ring->name, ret);
-				goto error_destroy_rbuf;
+			goto error_ringbuf;
 		}
 	}
 
-	}
-
 	ret = populate_lr_context(ctx, ctx_obj, ring, ringbuf);
 	if (ret) {
 		DRM_DEBUG_DRIVER("Failed to populate LRC: %d\n", ret);
@@ -2519,10 +2496,8 @@ int intel_lr_context_deferred_create(struct intel_context *ctx,
 error:
 	if (is_global_default_ctx)
 		intel_unpin_ringbuffer_obj(ringbuf);
-error_destroy_rbuf:
-	intel_destroy_ringbuffer_obj(ringbuf);
-error_free_rbuf:
-	kfree(ringbuf);
+error_ringbuf:
+	intel_ringbuffer_free(ringbuf);
 error_unpin_ctx:
 	if (is_global_default_ctx)
 		i915_gem_object_ggtt_unpin(ctx_obj);

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -1996,13 +1996,13 @@ int intel_pin_and_map_ringbuffer_obj(struct drm_device *dev,
 	return 0;
 }
 
-void intel_destroy_ringbuffer_obj(struct intel_ringbuffer *ringbuf)
+static void intel_destroy_ringbuffer_obj(struct intel_ringbuffer *ringbuf)
 {
 	drm_gem_object_unreference(&ringbuf->obj->base);
 	ringbuf->obj = NULL;
 }
 
-int intel_alloc_ringbuffer_obj(struct drm_device *dev,
+static int intel_alloc_ringbuffer_obj(struct drm_device *dev,
 				      struct intel_ringbuffer *ringbuf)
 {
 	struct drm_i915_gem_object *obj;
@@ -2023,6 +2023,48 @@ int intel_alloc_ringbuffer_obj(struct drm_device *dev,
 	return 0;
 }
 
+struct intel_ringbuffer *
+intel_engine_create_ringbuffer(struct intel_engine_cs *engine, int size)
+{
+	struct intel_ringbuffer *ring;
+	int ret;
+
+	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
+	if (ring == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	ring->ring = engine;
+
+	ring->size = size;
+	/* Workaround an erratum on the i830 which causes a hang if
+	 * the TAIL pointer points to within the last 2 cachelines
+	 * of the buffer.
+	 */
+	ring->effective_size = size;
+	if (IS_I830(engine->dev) || IS_845G(engine->dev))
+		ring->effective_size -= 2 * CACHELINE_BYTES;
+
+	ring->last_retired_head = -1;
+	intel_ring_update_space(ring);
+
+	ret = intel_alloc_ringbuffer_obj(engine->dev, ring);
+	if (ret) {
+		DRM_ERROR("Failed to allocate ringbuffer %s: %d\n",
+			  engine->name, ret);
+		kfree(ring);
+		return ERR_PTR(ret);
+	}
+
+	return ring;
+}
+
+void
+intel_ringbuffer_free(struct intel_ringbuffer *ring)
+{
+	intel_destroy_ringbuffer_obj(ring);
+	kfree(ring);
+}
+
 static int intel_init_ring_buffer(struct drm_device *dev,
 				  struct intel_engine_cs *ring)
 {
@@ -2031,22 +2073,20 @@ static int intel_init_ring_buffer(struct drm_device *dev,
 
 	WARN_ON(ring->buffer);
 
-	ringbuf = kzalloc(sizeof(*ringbuf), GFP_KERNEL);
-	if (!ringbuf)
-		return -ENOMEM;
-	ring->buffer = ringbuf;
-
 	ring->dev = dev;
 	INIT_LIST_HEAD(&ring->active_list);
 	INIT_LIST_HEAD(&ring->request_list);
 	INIT_LIST_HEAD(&ring->execlist_queue);
 	i915_gem_batch_pool_init(dev, &ring->batch_pool);
-	ringbuf->size = 32 * PAGE_SIZE;
-	ringbuf->ring = ring;
 	memset(ring->semaphore.sync_seqno, 0, sizeof(ring->semaphore.sync_seqno));
 
 	init_waitqueue_head(&ring->irq_queue);
 
+	ringbuf = intel_engine_create_ringbuffer(ring, 32 * PAGE_SIZE);
+	if (IS_ERR(ringbuf))
+		return PTR_ERR(ringbuf);
+	ring->buffer = ringbuf;
+
 	if (I915_NEED_GFX_HWS(dev)) {
 		ret = init_status_page(ring);
 		if (ret)
@@ -2058,15 +2098,6 @@ static int intel_init_ring_buffer(struct drm_device *dev,
 			goto error;
 	}
 
-	WARN_ON(ringbuf->obj);
-
-	ret = intel_alloc_ringbuffer_obj(dev, ringbuf);
-	if (ret) {
-		DRM_ERROR("Failed to allocate ringbuffer %s: %d\n",
-				ring->name, ret);
-		goto error;
-	}
-
 	ret = intel_pin_and_map_ringbuffer_obj(dev, ringbuf);
 	if (ret) {
 		DRM_ERROR("Failed to pin and map ringbuffer %s: %d\n",
@@ -2075,14 +2106,6 @@ static int intel_init_ring_buffer(struct drm_device *dev,
 		goto error;
 	}
 
-	/* Workaround an erratum on the i830 which causes a hang if
-	 * the TAIL pointer points to within the last 2 cachelines
-	 * of the buffer.
-	 */
-	ringbuf->effective_size = ringbuf->size;
-	if (IS_I830(dev) || IS_845G(dev))
-		ringbuf->effective_size -= 2 * CACHELINE_BYTES;
-
 	ret = i915_cmd_parser_init_ring(ring);
 	if (ret)
 		goto error;
@@ -2090,7 +2113,7 @@ static int intel_init_ring_buffer(struct drm_device *dev,
 	return 0;
 
 error:
-	kfree(ringbuf);
+	intel_ringbuffer_free(ringbuf);
 	ring->buffer = NULL;
 	return ret;
 }
@@ -2098,19 +2121,18 @@ static int intel_init_ring_buffer(struct drm_device *dev,
 void intel_cleanup_ring_buffer(struct intel_engine_cs *ring)
 {
 	struct drm_i915_private *dev_priv;
-	struct intel_ringbuffer *ringbuf;
 
 	if (!intel_ring_initialized(ring))
 		return;
 
 	dev_priv = to_i915(ring->dev);
-	ringbuf = ring->buffer;
 
 	intel_stop_ring_buffer(ring);
 	WARN_ON(!IS_GEN2(ring->dev) && (I915_READ_MODE(ring) & MODE_IDLE) == 0);
 
-	intel_unpin_ringbuffer_obj(ringbuf);
-	intel_destroy_ringbuffer_obj(ringbuf);
+	intel_unpin_ringbuffer_obj(ring->buffer);
+	intel_ringbuffer_free(ring->buffer);
+	ring->buffer = NULL;
 
 	if (ring->cleanup)
 		ring->cleanup(ring);
@@ -2119,9 +2141,6 @@ void intel_cleanup_ring_buffer(struct intel_engine_cs *ring)
 
 	i915_cmd_parser_fini_ring(ring);
 	i915_gem_batch_pool_fini(&ring->batch_pool);
-
-	kfree(ringbuf);
-	ring->buffer = NULL;
 }
 
 static int ring_wait_for_space(struct intel_engine_cs *ring, int n)

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -420,12 +420,12 @@ intel_write_status_page(struct intel_engine_cs *ring,
 #define I915_GEM_HWS_SCRATCH_INDEX	0x40
 #define I915_GEM_HWS_SCRATCH_ADDR (I915_GEM_HWS_SCRATCH_INDEX << MI_STORE_DWORD_INDEX_SHIFT)
 
-void intel_unpin_ringbuffer_obj(struct intel_ringbuffer *ringbuf);
+struct intel_ringbuffer *
+intel_engine_create_ringbuffer(struct intel_engine_cs *engine, int size);
 int intel_pin_and_map_ringbuffer_obj(struct drm_device *dev,
 				     struct intel_ringbuffer *ringbuf);
-void intel_destroy_ringbuffer_obj(struct intel_ringbuffer *ringbuf);
-int intel_alloc_ringbuffer_obj(struct drm_device *dev,
-			       struct intel_ringbuffer *ringbuf);
+void intel_unpin_ringbuffer_obj(struct intel_ringbuffer *ringbuf);
+void intel_ringbuffer_free(struct intel_ringbuffer *ring);
 
 void intel_stop_ring_buffer(struct intel_engine_cs *ring);
 void intel_cleanup_ring_buffer(struct intel_engine_cs *ring);