[PATCH 07/13] drm/i915/bdw: implement semaphore wait

Ben Widawsky
2014-02-20T06:19:34Z

Semaphore waits use a new instruction, MI_SEMAPHORE_WAIT. The seqno to
wait on is all well defined by the table in the previous patch. There is
nothing else different from previous GEN's semaphore synchronization
code.

v2: Update macros to not require the other ring's ring->id (Chris)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
drivers/gpu/drm/i915/i915_reg.h | 3 +++
drivers/gpu/drm/i915/intel_ringbuffer.c | 33 +++++++++++++++++++++++++++++----
drivers/gpu/drm/i915/intel_ringbuffer.h | 4 ++--
3 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 4e36d03..d02b856 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -242,6 +242,9 @@
#define MI_RESTORE_INHIBIT (1<<0)
#define MI_SEMAPHORE_SIGNAL MI_INSTR(0x1b, 0) /* GEN8+ */
#define MI_SEMAPHORE_TARGET(engine) ((engine)<<15)
+#define MI_SEMAPHORE_WAIT MI_INSTR(0x1c, 2) /* GEN8+ */
+#define MI_SEMAPHORE_POLL (1<<15)
+#define MI_SEMAPHORE_SAD_GTE_SDD (1<<12)
#define MI_STORE_DWORD_IMM MI_INSTR(0x20, 1)
#define MI_MEM_VIRTUAL (1 << 22) /* 965+ only */
#define MI_STORE_DWORD_INDEX MI_INSTR(0x21, 1)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 717976b..3d5dd4a 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -798,6 +798,31 @@ static inline bool i915_gem_has_seqno_wrapped(struct drm_device *dev,
* @signaller - ring which has, or will signal
* @seqno - seqno which the waiter will block on
*/
+
+static int
+gen8_ring_sync(struct intel_ring_buffer *waiter,
+ struct intel_ring_buffer *signaller,
+ u32 seqno)
+{
+ struct drm_i915_private *dev_priv = waiter->dev->dev_private;
+ int ret;
+
+ ret = intel_ring_begin(waiter, 4);
+ if (ret)
+ return ret;
+
+ intel_ring_emit(waiter, MI_SEMAPHORE_WAIT |
+ MI_SEMAPHORE_GLOBAL_GTT |
+ MI_SEMAPHORE_SAD_GTE_SDD);
+ intel_ring_emit(waiter, seqno);
+ intel_ring_emit(waiter,
+ lower_32_bits(GEN8_WAIT_OFFSET(waiter, signaller->id)));
+ intel_ring_emit(waiter,
+ upper_32_bits(GEN8_WAIT_OFFSET(waiter, signaller->id)));
+ intel_ring_advance(waiter);
+ return 0;
+}
+
static int
gen6_ring_sync(struct intel_ring_buffer *waiter,
struct intel_ring_buffer *signaller,
@@ -1984,7 +2009,7 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
ring->set_seqno = ring_set_seqno;
if (i915_semaphore_is_enabled(dev)) {
BUG_ON(!dev_priv->semaphore_obj);
- ring->semaphore.sync_to = gen6_ring_sync;
+ ring->semaphore.sync_to = gen8_ring_sync;
ring->semaphore.signal = gen8_rcs_signal;
GEN8_RING_SEMAPHORE_INIT;
}
@@ -2169,7 +2194,7 @@ int intel_init_bsd_ring_buffer(struct drm_device *dev)
ring->dispatch_execbuffer =
gen8_ring_dispatch_execbuffer;
if (i915_semaphore_is_enabled(dev)) {
- ring->semaphore.sync_to = gen6_ring_sync;
+ ring->semaphore.sync_to = gen8_ring_sync;
ring->semaphore.signal = gen8_xcs_signal;
GEN8_RING_SEMAPHORE_INIT;
}
@@ -2235,7 +2260,7 @@ int intel_init_blt_ring_buffer(struct drm_device *dev)
ring->irq_put = gen8_ring_put_irq;
ring->dispatch_execbuffer = gen8_ring_dispatch_execbuffer;
if (i915_semaphore_is_enabled(dev)) {
- ring->semaphore.sync_to = gen6_ring_sync;
+ ring->semaphore.sync_to = gen8_ring_sync;
ring->semaphore.signal = gen8_xcs_signal;
GEN8_RING_SEMAPHORE_INIT;
}
@@ -2284,7 +2309,7 @@ int intel_init_vebox_ring_buffer(struct drm_device *dev)
ring->irq_put = gen8_ring_put_irq;
ring->dispatch_execbuffer = gen8_ring_dispatch_execbuffer;
if (i915_semaphore_is_enabled(dev)) {
- ring->semaphore.sync_to = gen6_ring_sync;
+ ring->semaphore.sync_to = gen8_ring_sync;
ring->semaphore.signal = gen8_xcs_signal;
GEN8_RING_SEMAPHORE_INIT;
}
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 38a50c3..5d56c95 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -42,10 +42,10 @@ struct intel_hw_status_page {
(ring->id * I915_NUM_RINGS * i915_semaphore_seqno_size) + \
(i915_semaphore_seqno_size * (to)))

-#define GEN8_WAIT_OFFSET(from) \
+#define GEN8_WAIT_OFFSET(__ring, from) \
(i915_gem_obj_ggtt_offset(dev_priv->semaphore_obj) + \
((from) * I915_NUM_RINGS * i915_semaphore_seqno_size) + \
- (i915_semaphore_seqno_size * ring->id))
+ (i915_semaphore_seqno_size * (__ring)->id))

#define GEN8_RING_SEMAPHORE_INIT do { \
if (!dev_priv->semaphore_obj) { \
--
1.9.0