drm/i915: Implement GPU semaphores for inter-ring synchronisation on SNB

The bulk of the change is to convert the growing list of rings into an
array so that the relationship between the rings and the semaphore sync
registers can be easily computed.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 37 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 8e3526777926..6a3822bc6af2 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -1,6 +1,13 @@
 #ifndef _INTEL_RINGBUFFER_H_
 #define _INTEL_RINGBUFFER_H_
 
+enum {
+    RCS = 0x0,
+    VCS,
+    BCS,
+    I915_NUM_RINGS,
+};
+
 struct  intel_hw_status_page {
 	u32	__iomem	*page_addr;
 	unsigned int	gfx_addr;
@@ -21,7 +28,10 @@ struct  intel_hw_status_page {
 #define I915_READ_CTL(ring) I915_RING_READ(RING_CTL(ring->mmio_base))
 #define I915_WRITE_CTL(ring, val) I915_WRITE(RING_CTL(ring->mmio_base), val)
 
-struct drm_i915_gem_execbuffer2;
+#define I915_READ_NOPID(ring) I915_RING_READ(RING_NOPID(ring->mmio_base))
+#define I915_READ_SYNC_0(ring) I915_RING_READ(RING_SYNC_0(ring->mmio_base))
+#define I915_READ_SYNC_1(ring) I915_RING_READ(RING_SYNC_1(ring->mmio_base))
+
 struct  intel_ring_buffer {
 	const char	*name;
 	enum intel_ring_id {
@@ -42,9 +52,10 @@ struct  intel_ring_buffer {
 
 	u32		irq_seqno;		/* last seq seem at irq time */
 	u32		waiting_seqno;
-	int		user_irq_refcount;
-	void		(*user_irq_get)(struct intel_ring_buffer *ring);
-	void		(*user_irq_put)(struct intel_ring_buffer *ring);
+	u32		sync_seqno[I915_NUM_RINGS-1];
+	u32		irq_refcount;
+	void		(*irq_get)(struct intel_ring_buffer *ring);
+	void		(*irq_put)(struct intel_ring_buffer *ring);
 
 	int		(*init)(struct intel_ring_buffer *ring);
 
@@ -99,6 +110,25 @@ struct  intel_ring_buffer {
 };
 
 static inline u32
+intel_ring_sync_index(struct intel_ring_buffer *ring,
+		      struct intel_ring_buffer *other)
+{
+	int idx;
+
+	/*
+	 * cs -> 0 = vcs, 1 = bcs
+	 * vcs -> 0 = bcs, 1 = cs,
+	 * bcs -> 0 = cs, 1 = vcs.
+	 */
+
+	idx = (other - ring) - 1;
+	if (idx < 0)
+		idx += I915_NUM_RINGS;
+
+	return idx;
+}
+
+static inline u32
 intel_read_status_page(struct intel_ring_buffer *ring,
 		       int reg)
 {
@@ -119,6 +149,9 @@ static inline void intel_ring_emit(struct intel_ring_buffer *ring,
 void intel_ring_advance(struct intel_ring_buffer *ring);
 
 u32 intel_ring_get_seqno(struct intel_ring_buffer *ring);
+int intel_ring_sync(struct intel_ring_buffer *ring,
+		    struct intel_ring_buffer *to,
+		    u32 seqno);
 
 int intel_init_render_ring_buffer(struct drm_device *dev);
 int intel_init_bsd_ring_buffer(struct drm_device *dev);