[Intel-gfx] [PATCH 13/49] drm/i915/bdw: Execlists ring tail writing

[oscar.mateo at intel.com]

From: Oscar Mateo <oscar.mateo at intel.com>

The write tail function is a very special place for execlists: since
all access to the ring is mediated through requests (thanks to
Chris Wilson's "Write RING_TAIL once per-request" for that) and all
requests end up with a write tail, this is the place we are going to
use to submit contexts for execution.

For the moment, just mark the place (we still need to do a lot of
preparation before execlists are ready to start submitting things).

Signed-off-by: Oscar Mateo <oscar.mateo at intel.com>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 35e022f..a18dcf7 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -413,6 +413,12 @@ static void ring_write_tail(struct intel_engine *ring,
 	I915_WRITE_TAIL(ring, value);
 }
 
+static void gen8_write_tail_lrc(struct intel_engine *ring,
+				u32 value)
+{
+	DRM_ERROR("Execlists still not ready!\n");
+}
+
 u32 intel_ring_get_active_head(struct intel_engine *ring)
 {
 	drm_i915_private_t *dev_priv = ring->dev->dev_private;
@@ -1907,12 +1913,15 @@ int intel_init_render_ring(struct drm_device *dev)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct intel_engine *ring = &dev_priv->ring[RCS];
 
+	ring->write_tail = ring_write_tail;
 	if (INTEL_INFO(dev)->gen >= 6) {
 		ring->add_request = gen6_add_request;
 		ring->flush = gen7_render_ring_flush;
 		if (INTEL_INFO(dev)->gen == 6)
 			ring->flush = gen6_render_ring_flush;
 		if (INTEL_INFO(dev)->gen >= 8) {
+			if (dev_priv->lrc_enabled)
+				ring->write_tail = gen8_write_tail_lrc;
 			ring->flush = gen8_render_ring_flush;
 			ring->irq_get = gen8_ring_get_irq;
 			ring->irq_put = gen8_ring_put_irq;
@@ -1958,7 +1967,7 @@ int intel_init_render_ring(struct drm_device *dev)
 		}
 		ring->irq_enable_mask = I915_USER_INTERRUPT;
 	}
-	ring->write_tail = ring_write_tail;
+
 	if (IS_HASWELL(dev))
 		ring->dispatch_execbuffer = hsw_ring_dispatch_execbuffer;
 	else if (IS_GEN8(dev))
@@ -2079,6 +2088,8 @@ int intel_init_bsd_ring(struct drm_device *dev)
 		ring->get_seqno = gen6_ring_get_seqno;
 		ring->set_seqno = ring_set_seqno;
 		if (INTEL_INFO(dev)->gen >= 8) {
+			if (dev_priv->lrc_enabled)
+				ring->write_tail = gen8_write_tail_lrc;
 			ring->irq_enable_mask =
 				GT_RENDER_USER_INTERRUPT << GEN8_VCS1_IRQ_SHIFT;
 			ring->irq_get = gen8_ring_get_irq;
@@ -2133,6 +2144,8 @@ int intel_init_blt_ring(struct drm_device *dev)
 	ring->get_seqno = gen6_ring_get_seqno;
 	ring->set_seqno = ring_set_seqno;
 	if (INTEL_INFO(dev)->gen >= 8) {
+		if (dev_priv->lrc_enabled)
+			ring->write_tail = gen8_write_tail_lrc;
 		ring->irq_enable_mask =
 			GT_RENDER_USER_INTERRUPT << GEN8_BCS_IRQ_SHIFT;
 		ring->irq_get = gen8_ring_get_irq;
@@ -2170,6 +2183,8 @@ int intel_init_vebox_ring(struct drm_device *dev)
 	ring->set_seqno = ring_set_seqno;
 
 	if (INTEL_INFO(dev)->gen >= 8) {
+		if (dev_priv->lrc_enabled)
+			ring->write_tail = gen8_write_tail_lrc;
 		ring->irq_enable_mask =
 			GT_RENDER_USER_INTERRUPT << GEN8_VECS_IRQ_SHIFT;
 		ring->irq_get = gen8_ring_get_irq;
-- 
1.9.0