drm/i915: implement BSD ring buffer V2

The BSD (bit stream decoder) ring is used for accessing the BSD engine
which decodes video bitstream for H.264 and VC1 on G45+.  It is
asynchronous with the render ring and has access to separate parts of
the GPU from it, though the render cache is coherent between the two.

Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
Signed-off-by: Xiang Hai hao <haihao.xiang@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

6 files changed, 276 insertions, 15 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index f485880..1dbed70 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -130,6 +130,8 @@ static int i915_dma_cleanup(struct drm_device * dev)
 		drm_irq_uninstall(dev);
 
 	intel_cleanup_ring_buffer(dev, &dev_priv->render_ring);
+	if (HAS_BSD(dev))
+		intel_cleanup_ring_buffer(dev, &dev_priv->bsd_ring);
 
 	/* Clear the HWS virtual address at teardown */
 	if (I915_NEED_GFX_HWS(dev))
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 3f35989..6bc0fc08 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -235,6 +235,7 @@ typedef struct drm_i915_private {
 
 	struct pci_dev *bridge_dev;
 	struct intel_ring_buffer render_ring;
+	struct intel_ring_buffer bsd_ring;
 
 	drm_dma_handle_t *status_page_dmah;
 	void *hw_status_page;
@@ -1121,6 +1122,7 @@ extern int intel_trans_dp_port_sel (struct drm_crtc *crtc);
 			 (dev)->pci_device == 0x2A42 ||		\
 			 (dev)->pci_device == 0x2E42)
 
+#define HAS_BSD(dev)            (IS_IRONLAKE(dev) || IS_G4X(dev))
 #define I915_NEED_GFX_HWS(dev)	(INTEL_INFO(dev)->need_gfx_hws)
 
 /* With the 945 and later, Y tiling got adjusted so that it was 32 128-byte
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index af664ba..c51495f 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1730,7 +1730,7 @@ i915_seqno_passed(uint32_t seq1, uint32_t seq2)
 
 uint32_t
 i915_get_gem_seqno(struct drm_device *dev,
-		struct intel_ring_buffer *ring)
+		   struct intel_ring_buffer *ring)
 {
 	return ring->get_gem_seqno(dev, ring);
 }
@@ -1792,8 +1792,13 @@ i915_gem_retire_work_handler(struct work_struct *work)
 	mutex_lock(&dev->struct_mutex);
 	i915_gem_retire_requests(dev, &dev_priv->render_ring);
 
+	if (HAS_BSD(dev))
+		i915_gem_retire_requests(dev, &dev_priv->bsd_ring);
+
 	if (!dev_priv->mm.suspended &&
-			(!list_empty(&dev_priv->render_ring.request_list)))
+		(!list_empty(&dev_priv->render_ring.request_list) ||
+			(HAS_BSD(dev) &&
+			 !list_empty(&dev_priv->bsd_ring.request_list))))
 		queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, HZ);
 	mutex_unlock(&dev->struct_mutex);
 }
@@ -1883,6 +1888,11 @@ i915_gem_flush(struct drm_device *dev,
 	dev_priv->render_ring.flush(dev, &dev_priv->render_ring,
 			invalidate_domains,
 			flush_domains);
+
+	if (HAS_BSD(dev))
+		dev_priv->bsd_ring.flush(dev, &dev_priv->bsd_ring,
+				invalidate_domains,
+				flush_domains);
 }
 
 static void
@@ -2039,12 +2049,14 @@ i915_gpu_idle(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	bool lists_empty;
-	uint32_t seqno;
+	uint32_t seqno1, seqno2;
 	int ret;
 
 	spin_lock(&dev_priv->mm.active_list_lock);
-	lists_empty = list_empty(&dev_priv->mm.flushing_list) &&
-		      list_empty(&dev_priv->render_ring.active_list);
+	lists_empty = (list_empty(&dev_priv->mm.flushing_list) &&
+		       list_empty(&dev_priv->render_ring.active_list) &&
+		       (!HAS_BSD(dev) ||
+			list_empty(&dev_priv->bsd_ring.active_list)));
 	spin_unlock(&dev_priv->mm.active_list_lock);
 
 	if (lists_empty)
@@ -2052,11 +2064,23 @@ i915_gpu_idle(struct drm_device *dev)
 
 	/* Flush everything onto the inactive list. */
 	i915_gem_flush(dev, I915_GEM_GPU_DOMAINS, I915_GEM_GPU_DOMAINS);
-	seqno = i915_add_request(dev, NULL, I915_GEM_GPU_DOMAINS,
+	seqno1 = i915_add_request(dev, NULL, I915_GEM_GPU_DOMAINS,
 			&dev_priv->render_ring);
-	if (seqno == 0)
+	if (seqno1 == 0)
 		return -ENOMEM;
-	ret = i915_wait_request(dev, seqno, &dev_priv->render_ring);
+	ret = i915_wait_request(dev, seqno1, &dev_priv->render_ring);
+
+	if (HAS_BSD(dev)) {
+		seqno2 = i915_add_request(dev, NULL, I915_GEM_GPU_DOMAINS,
+				&dev_priv->bsd_ring);
+		if (seqno2 == 0)
+			return -ENOMEM;
+
+		ret = i915_wait_request(dev, seqno2, &dev_priv->bsd_ring);
+		if (ret)
+			return ret;
+	}
+
 
 	return ret;
 }
@@ -2071,7 +2095,9 @@ i915_gem_evict_everything(struct drm_device *dev)
 	spin_lock(&dev_priv->mm.active_list_lock);
 	lists_empty = (list_empty(&dev_priv->mm.inactive_list) &&
 		       list_empty(&dev_priv->mm.flushing_list) &&
-		       list_empty(&dev_priv->render_ring.active_list));
+		       list_empty(&dev_priv->render_ring.active_list) &&
+		       (!HAS_BSD(dev)
+			|| list_empty(&dev_priv->bsd_ring.active_list)));
 	spin_unlock(&dev_priv->mm.active_list_lock);
 
 	if (lists_empty)
@@ -2091,7 +2117,9 @@ i915_gem_evict_everything(struct drm_device *dev)
 	spin_lock(&dev_priv->mm.active_list_lock);
 	lists_empty = (list_empty(&dev_priv->mm.inactive_list) &&
 		       list_empty(&dev_priv->mm.flushing_list) &&
-		       list_empty(&dev_priv->render_ring.active_list));
+		       list_empty(&dev_priv->render_ring.active_list) &&
+		       (!HAS_BSD(dev)
+			|| list_empty(&dev_priv->bsd_ring.active_list)));
 	spin_unlock(&dev_priv->mm.active_list_lock);
 	BUG_ON(!lists_empty);
 
@@ -2106,9 +2134,13 @@ i915_gem_evict_something(struct drm_device *dev, int min_size)
 	int ret;
 
 	struct intel_ring_buffer *render_ring = &dev_priv->render_ring;
+	struct intel_ring_buffer *bsd_ring = &dev_priv->bsd_ring;
 	for (;;) {
 		i915_gem_retire_requests(dev, render_ring);
 
+		if (HAS_BSD(dev))
+			i915_gem_retire_requests(dev, bsd_ring);
+
 		/* If there's an inactive buffer available now, grab it
 		 * and be done.
 		 */
@@ -2146,6 +2178,21 @@ i915_gem_evict_something(struct drm_device *dev, int min_size)
 			continue;
 		}
 
+		if (HAS_BSD(dev) && !list_empty(&bsd_ring->request_list)) {
+			struct drm_i915_gem_request *request;
+
+			request = list_first_entry(&bsd_ring->request_list,
+						   struct drm_i915_gem_request,
+						   list);
+
+			ret = i915_wait_request(dev,
+					request->seqno, request->ring);
+			if (ret)
+				return ret;
+
+			continue;
+		}
+
 		/* If we didn't have anything on the request list but there
 		 * are buffers awaiting a flush, emit one and try again.
 		 * When we wait on it, those buffers waiting for that flush
@@ -3641,6 +3688,16 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 	DRM_INFO("buffers_ptr %d buffer_count %d len %08x\n",
 		  (int) args->buffers_ptr, args->buffer_count, args->batch_len);
 #endif
+	if (args->flags & I915_EXEC_BSD) {
+		if (!HAS_BSD(dev)) {
+			DRM_ERROR("execbuf with wrong flag\n");
+			return -EINVAL;
+		}
+		ring = &dev_priv->bsd_ring;
+	} else {
+		ring = &dev_priv->render_ring;
+	}
+
 
 	if (args->buffer_count < 1) {
 		DRM_ERROR("execbuf with %d buffers\n", args->buffer_count);
@@ -3694,8 +3751,6 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 		goto pre_mutex_err;
 	}
 
-	ring = &dev_priv->render_ring;
-
 	/* Look up object handles */
 	flips = 0;
 	for (i = 0; i < args->buffer_count; i++) {
@@ -3834,6 +3889,10 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 					dev->flush_domains,
 					&dev_priv->render_ring);
 
+			if (HAS_BSD(dev))
+				(void)i915_add_request(dev, file_priv,
+						dev->flush_domains,
+						&dev_priv->bsd_ring);
 		}
 	}
 
@@ -4267,6 +4326,9 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
 	 */
 	i915_gem_retire_requests(dev, &dev_priv->render_ring);
 
+	if (HAS_BSD(dev))
+		i915_gem_retire_requests(dev, &dev_priv->bsd_ring);
+
 	obj_priv = to_intel_bo(obj);
 	/* Don't count being on the flushing list against the object being
 	 * done.  Otherwise, a buffer left on the flushing list but not getting
@@ -4433,7 +4495,9 @@ i915_gem_idle(struct drm_device *dev)
 	mutex_lock(&dev->struct_mutex);
 
 	if (dev_priv->mm.suspended ||
-			dev_priv->render_ring.gem_object == NULL) {
+			(dev_priv->render_ring.gem_object == NULL) ||
+			(HAS_BSD(dev) &&
+			 dev_priv->bsd_ring.gem_object == NULL)) {
 		mutex_unlock(&dev->struct_mutex);
 		return 0;
 	}
@@ -4550,6 +4614,10 @@ i915_gem_init_ringbuffer(struct drm_device *dev)
 			return ret;
 	}
 	ret = intel_init_ring_buffer(dev, &dev_priv->render_ring);
+	if (!ret && HAS_BSD(dev)) {
+		dev_priv->bsd_ring = bsd_ring;
+		ret = intel_init_ring_buffer(dev, &dev_priv->bsd_ring);
+	}
 	return ret;
 }
 
@@ -4559,6 +4627,8 @@ i915_gem_cleanup_ringbuffer(struct drm_device *dev)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 
 	intel_cleanup_ring_buffer(dev, &dev_priv->render_ring);
+	if (HAS_BSD(dev))
+		intel_cleanup_ring_buffer(dev, &dev_priv->bsd_ring);
 	if (HAS_PIPE_CONTROL(dev))
 		i915_gem_cleanup_pipe_control(dev);
 }
@@ -4589,11 +4659,13 @@ i915_gem_entervt_ioctl(struct drm_device *dev, void *data,
 
 	spin_lock(&dev_priv->mm.active_list_lock);
 	BUG_ON(!list_empty(&dev_priv->render_ring.active_list));
+	BUG_ON(HAS_BSD(dev) && !list_empty(&dev_priv->bsd_ring.active_list));
 	spin_unlock(&dev_priv->mm.active_list_lock);
 
 	BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
 	BUG_ON(!list_empty(&dev_priv->mm.inactive_list));
 	BUG_ON(!list_empty(&dev_priv->render_ring.request_list));
+	BUG_ON(HAS_BSD(dev) && !list_empty(&dev_priv->bsd_ring.request_list));
 	mutex_unlock(&dev->struct_mutex);
 
 	drm_irq_install(dev);
@@ -4638,6 +4710,10 @@ i915_gem_load(struct drm_device *dev)
 	INIT_LIST_HEAD(&dev_priv->mm.fence_list);
 	INIT_LIST_HEAD(&dev_priv->render_ring.active_list);
 	INIT_LIST_HEAD(&dev_priv->render_ring.request_list);
+	if (HAS_BSD(dev)) {
+		INIT_LIST_HEAD(&dev_priv->bsd_ring.active_list);
+		INIT_LIST_HEAD(&dev_priv->bsd_ring.request_list);
+	}
 	for (i = 0; i < 16; i++)
 		INIT_LIST_HEAD(&dev_priv->fence_regs[i].lru_list);
 	INIT_DELAYED_WORK(&dev_priv->mm.retire_work,
@@ -4874,6 +4950,8 @@ i915_gpu_is_active(struct drm_device *dev)
 	spin_lock(&dev_priv->mm.active_list_lock);
 	lists_empty = list_empty(&dev_priv->mm.flushing_list) &&
 		      list_empty(&dev_priv->render_ring.active_list);
+	if (HAS_BSD(dev))
+		lists_empty &= list_empty(&dev_priv->bsd_ring.active_list);
 	spin_unlock(&dev_priv->mm.active_list_lock);
 
 	return !lists_empty;
@@ -4920,6 +4998,9 @@ rescan:
 		spin_unlock(&shrink_list_lock);
 		i915_gem_retire_requests(dev, &dev_priv->render_ring);
 
+		if (HAS_BSD(dev))
+			i915_gem_retire_requests(dev, &dev_priv->bsd_ring);
+
 		list_for_each_entry_safe(obj_priv, next_obj,
 					 &dev_priv->mm.inactive_list,
 					 list) {
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 8a667f1..0a3a580 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -53,7 +53,7 @@
 	 I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT)
 
 /** Interrupts that we mask and unmask at runtime. */
-#define I915_INTERRUPT_ENABLE_VAR (I915_USER_INTERRUPT)
+#define I915_INTERRUPT_ENABLE_VAR (I915_USER_INTERRUPT | I915_BSD_USER_INTERRUPT)
 
 #define I915_PIPE_VBLANK_STATUS	(PIPE_START_VBLANK_INTERRUPT_STATUS |\
 				 PIPE_VBLANK_INTERRUPT_STATUS)
@@ -362,6 +362,9 @@ irqreturn_t ironlake_irq_handler(struct drm_device *dev)
 		dev_priv->hangcheck_count = 0;
 		mod_timer(&dev_priv->hangcheck_timer, jiffies + DRM_I915_HANGCHECK_PERIOD);
 	}
+	if (gt_iir & GT_BSD_USER_INTERRUPT)
+		DRM_WAKEUP(&dev_priv->bsd_ring.irq_queue);
+
 
 	if (de_iir & DE_GSE)
 		ironlake_opregion_gse_intr(dev);
@@ -944,6 +947,9 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
 			mod_timer(&dev_priv->hangcheck_timer, jiffies + DRM_I915_HANGCHECK_PERIOD);
 		}
 
+		if (HAS_BSD(dev) && (iir & I915_BSD_USER_INTERRUPT))
+			DRM_WAKEUP(&dev_priv->bsd_ring.irq_queue);
+
 		if (iir & I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT)
 			intel_prepare_page_flip(dev, 0);
 
@@ -1297,7 +1303,7 @@ static int ironlake_irq_postinstall(struct drm_device *dev)
 	/* enable kind of interrupts always enabled */
 	u32 display_mask = DE_MASTER_IRQ_CONTROL | DE_GSE | DE_PCH_EVENT |
 			   DE_PLANEA_FLIP_DONE | DE_PLANEB_FLIP_DONE;
-	u32 render_mask = GT_PIPE_NOTIFY;
+	u32 render_mask = GT_PIPE_NOTIFY | GT_BSD_USER_INTERRUPT;
 	u32 hotplug_mask = SDE_CRT_HOTPLUG | SDE_PORTB_HOTPLUG |
 			   SDE_PORTC_HOTPLUG | SDE_PORTD_HOTPLUG;
 
@@ -1376,6 +1382,9 @@ int i915_driver_irq_postinstall(struct drm_device *dev)
 
 	DRM_INIT_WAITQUEUE(&dev_priv->render_ring.irq_queue);
 
+	if (HAS_BSD(dev))
+		DRM_INIT_WAITQUEUE(&dev_priv->bsd_ring.irq_queue);
+
 	dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B;
 
 	if (HAS_PCH_SPLIT(dev))
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index f3e39cc..784cf3c 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -334,6 +334,7 @@
 #define   I915_DEBUG_INTERRUPT				(1<<2)
 #define   I915_USER_INTERRUPT				(1<<1)
 #define   I915_ASLE_INTERRUPT				(1<<0)
+#define   I915_BSD_USER_INTERRUPT                      (1<<25)
 #define EIR		0x020b0
 #define EMR		0x020b4
 #define ESR		0x020b8
@@ -368,6 +369,17 @@
 #define BB_ADDR		0x02140 /* 8 bytes */
 #define GFX_FLSH_CNTL	0x02170 /* 915+ only */
 
+/*
+ * BSD (bit stream decoder instruction and interrupt control register defines
+ * (G4X and Ironlake only)
+ */
+
+#define BSD_RING_TAIL          0x04030
+#define BSD_RING_HEAD          0x04034
+#define BSD_RING_START         0x04038
+#define BSD_RING_CTL           0x0403c
+#define BSD_RING_ACTHD         0x04074
+#define BSD_HWS_PGA            0x04080
 
 /*
  * Framebuffer compression (915+ only)
@@ -2355,6 +2367,8 @@
 #define GT_PIPE_NOTIFY		(1 << 4)
 #define GT_SYNC_STATUS          (1 << 2)
 #define GT_USER_INTERRUPT       (1 << 0)
+#define GT_BSD_USER_INTERRUPT   (1 << 5)
+
 
 #define GTISR   0x44010
 #define GTIMR   0x44014
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 5715c4d8..f6b84fe 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -340,6 +340,119 @@ static void render_setup_status_page(struct drm_device *dev,
 
 }
 
+void
+bsd_ring_flush(struct drm_device *dev,
+		struct intel_ring_buffer *ring,
+		u32     invalidate_domains,
+		u32     flush_domains)
+{
+	intel_ring_begin(dev, ring, 8);
+	intel_ring_emit(dev, ring, MI_FLUSH);
+	intel_ring_emit(dev, ring, MI_NOOP);
+	intel_ring_advance(dev, ring);
+}
+
+static inline unsigned int bsd_ring_get_head(struct drm_device *dev,
+		struct intel_ring_buffer *ring)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	return I915_READ(BSD_RING_HEAD) & HEAD_ADDR;
+}
+
+static inline unsigned int bsd_ring_get_tail(struct drm_device *dev,
+		struct intel_ring_buffer *ring)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	return I915_READ(BSD_RING_TAIL) & TAIL_ADDR;
+}
+
+static inline unsigned int bsd_ring_get_active_head(struct drm_device *dev,
+		struct intel_ring_buffer *ring)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	return I915_READ(BSD_RING_ACTHD);
+}
+
+static inline void bsd_ring_advance_ring(struct drm_device *dev,
+		struct intel_ring_buffer *ring)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	I915_WRITE(BSD_RING_TAIL, ring->tail);
+}
+
+static int init_bsd_ring(struct drm_device *dev,
+		struct intel_ring_buffer *ring)
+{
+	return init_ring_common(dev, ring);
+}
+
+static u32
+bsd_ring_add_request(struct drm_device *dev,
+		struct intel_ring_buffer *ring,
+		struct drm_file *file_priv,
+		u32 flush_domains)
+{
+	u32 seqno;
+	seqno = intel_ring_get_seqno(dev, ring);
+	intel_ring_begin(dev, ring, 4);
+	intel_ring_emit(dev, ring, MI_STORE_DWORD_INDEX);
+	intel_ring_emit(dev, ring,
+			I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT);
+	intel_ring_emit(dev, ring, seqno);
+	intel_ring_emit(dev, ring, MI_USER_INTERRUPT);
+	intel_ring_advance(dev, ring);
+
+	DRM_DEBUG_DRIVER("%s %d\n", ring->name, seqno);
+
+	return seqno;
+}
+
+static void bsd_setup_status_page(struct drm_device *dev,
+		struct  intel_ring_buffer *ring)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	I915_WRITE(BSD_HWS_PGA, ring->status_page.gfx_addr);
+	I915_READ(BSD_HWS_PGA);
+}
+
+static void
+bsd_ring_get_user_irq(struct drm_device *dev,
+		struct intel_ring_buffer *ring)
+{
+	/* do nothing */
+}
+static void
+bsd_ring_put_user_irq(struct drm_device *dev,
+		struct intel_ring_buffer *ring)
+{
+	/* do nothing */
+}
+
+static u32
+bsd_ring_get_gem_seqno(struct drm_device *dev,
+		struct intel_ring_buffer *ring)
+{
+	return intel_read_status_page(ring, I915_GEM_HWS_INDEX);
+}
+
+static int
+bsd_ring_dispatch_gem_execbuffer(struct drm_device *dev,
+		struct intel_ring_buffer *ring,
+		struct drm_i915_gem_execbuffer2 *exec,
+		struct drm_clip_rect *cliprects,
+		uint64_t exec_offset)
+{
+	uint32_t exec_start;
+	exec_start = (uint32_t) exec_offset + exec->batch_start_offset;
+	intel_ring_begin(dev, ring, 2);
+	intel_ring_emit(dev, ring, MI_BATCH_BUFFER_START |
+			(2 << 6) | MI_BATCH_NON_SECURE_I965);
+	intel_ring_emit(dev, ring, exec_start);
+	intel_ring_advance(dev, ring);
+	return 0;
+}
+
+
 static int
 render_ring_dispatch_gem_execbuffer(struct drm_device *dev,
 		struct intel_ring_buffer *ring,
@@ -588,6 +701,7 @@ int intel_wait_ring_buffer(struct drm_device *dev,
 			if (master_priv->sarea_priv)
 				master_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;
 		}
+
 		yield();
 	} while (!time_after(jiffies, end));
 	trace_i915_ring_wait_end (dev);
@@ -682,3 +796,42 @@ struct intel_ring_buffer render_ring = {
 	.status_page		= {NULL, 0, NULL},
 	.map			= {0,}
 };
+
+/* ring buffer for bit-stream decoder */
+
+struct intel_ring_buffer bsd_ring = {
+	.name                   = "bsd ring",
+	.regs			= {
+		.ctl = BSD_RING_CTL,
+		.head = BSD_RING_HEAD,
+		.tail = BSD_RING_TAIL,
+		.start = BSD_RING_START
+	},
+	.ring_flag		= I915_EXEC_BSD,
+	.size			= 32 * PAGE_SIZE,
+	.alignment		= PAGE_SIZE,
+	.virtual_start		= NULL,
+	.dev			= NULL,
+	.gem_object		= NULL,
+	.head			= 0,
+	.tail			= 0,
+	.space			= 0,
+	.next_seqno		= 1,
+	.user_irq_refcount	= 0,
+	.irq_gem_seqno		= 0,
+	.waiting_gem_seqno	= 0,
+	.setup_status_page	= bsd_setup_status_page,
+	.init			= init_bsd_ring,
+	.get_head		= bsd_ring_get_head,
+	.get_tail		= bsd_ring_get_tail,
+	.get_active_head	= bsd_ring_get_active_head,
+	.advance_ring		= bsd_ring_advance_ring,
+	.flush			= bsd_ring_flush,
+	.add_request		= bsd_ring_add_request,
+	.get_gem_seqno		= bsd_ring_get_gem_seqno,
+	.user_irq_get		= bsd_ring_get_user_irq,
+	.user_irq_put		= bsd_ring_put_user_irq,
+	.dispatch_gem_execbuffer = bsd_ring_dispatch_gem_execbuffer,
+	.status_page		= {NULL, 0, NULL},
+	.map			= {0,}
+};