i965/gen7: Add support for transform feedback.

Fixes almost all of the transform feedback piglit tests.  Remaining
are a few tests related to tesselation for
quads/trifans/tristrips/polygons with flat shading.

v2: Incorporate Paul's feedback (squash with previous, state flag note,
    static assert, update FINISHME)

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> (v1)
Reviewed-by: Paul Berry <stereotype441@gmail.com>

1 files changed, 201 insertions, 7 deletions

diff --git a/src/mesa/drivers/dri/i965/gen7_sol_state.c b/src/mesa/drivers/dri/i965/gen7_sol_state.c
index fcda08dde4f..3b6fc8ecb16 100644
--- a/src/mesa/drivers/dri/i965/gen7_sol_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_sol_state.c
@@ -32,25 +32,219 @@
 #include "brw_state.h"
 #include "brw_defines.h"
 #include "intel_batchbuffer.h"
+#include "intel_buffer_objects.h"
 
 static void
-upload_sol_state(struct brw_context *brw)
+upload_3dstate_so_buffers(struct brw_context *brw)
+{
+   struct intel_context *intel = &brw->intel;
+   struct gl_context *ctx = &intel->ctx;
+   /* BRW_NEW_VERTEX_PROGRAM */
+   const struct gl_shader_program *vs_prog =
+      ctx->Shader.CurrentVertexProgram;
+   const struct gl_transform_feedback_info *linked_xfb_info =
+      &vs_prog->LinkedTransformFeedback;
+   /* _NEW_TRANSFORM_FEEDBACK */
+   struct gl_transform_feedback_object *xfb_obj =
+      ctx->TransformFeedback.CurrentObject;
+   int i;
+
+   /* Set up the up to 4 output buffers.  These are the ranges defined in the
+    * gl_transform_feedback_object.
+    */
+   for (i = 0; i < 4; i++) {
+      struct gl_buffer_object *bufferobj = xfb_obj->Buffers[i];
+      drm_intel_bo *bo;
+      uint32_t start, end;
+
+      if (!xfb_obj->Buffers[i]) {
+	 /* The pitch of 0 in this command indicates that the buffer is
+	  * unbound and won't be written to.
+	  */
+	 BEGIN_BATCH(4);
+	 OUT_BATCH(_3DSTATE_SO_BUFFER << 16 | (4 - 2));
+	 OUT_BATCH((i << SO_BUFFER_INDEX_SHIFT));
+	 OUT_BATCH(0);
+	 OUT_BATCH(0);
+	 ADVANCE_BATCH();
+
+	 continue;
+      }
+
+      bo = intel_buffer_object(bufferobj)->buffer;
+
+      start = xfb_obj->Offset[i];
+      assert(start % 4 == 0);
+      end = ALIGN(start + xfb_obj->Size[i], 4);
+      assert(end <= bo->size);
+
+      BEGIN_BATCH(4);
+      OUT_BATCH(_3DSTATE_SO_BUFFER << 16 | (4 - 2));
+      OUT_BATCH((i << SO_BUFFER_INDEX_SHIFT) |
+		((linked_xfb_info->BufferStride[i] * 4) <<
+		 SO_BUFFER_PITCH_SHIFT));
+      OUT_RELOC(bo, I915_GEM_DOMAIN_RENDER, I915_GEM_DOMAIN_RENDER, start);
+      OUT_RELOC(bo, I915_GEM_DOMAIN_RENDER, I915_GEM_DOMAIN_RENDER, end);
+      ADVANCE_BATCH();
+   }
+}
+
+/**
+ * Outputs the 3DSTATE_SO_DECL_LIST command.
+ *
+ * The data output is a series of 64-bit entries containing a SO_DECL per
+ * stream.  We only have one stream of rendering coming out of the GS unit, so
+ * we only emit stream 0 (low 16 bits) SO_DECLs.
+ */
+static void
+upload_3dstate_so_decl_list(struct brw_context *brw,
+			    struct brw_vue_map *vue_map)
 {
    struct intel_context *intel = &brw->intel;
+   struct gl_context *ctx = &intel->ctx;
+   /* BRW_NEW_VERTEX_PROGRAM */
+   const struct gl_shader_program *vs_prog =
+      ctx->Shader.CurrentVertexProgram;
+   /* _NEW_TRANSFORM_FEEDBACK */
+   const struct gl_transform_feedback_info *linked_xfb_info =
+      &vs_prog->LinkedTransformFeedback;
+   int i;
+   uint16_t so_decl[128];
+   int buffer_mask = 0;
+   int next_offset[4] = {0, 0, 0, 0};
+
+   STATIC_ASSERT(ARRAY_SIZE(so_decl) >= MAX_PROGRAM_OUTPUTS);
+
+   /* Construct the list of SO_DECLs to be emitted.  The formatting of the
+    * command is feels strange -- each dword pair contains a SO_DECL per stream.
+    */
+   for (i = 0; i < linked_xfb_info->NumOutputs; i++) {
+      int buffer = linked_xfb_info->Outputs[i].OutputBuffer;
+      uint16_t decl = 0;
+      int vert_result = linked_xfb_info->Outputs[i].OutputRegister;
+
+      buffer_mask |= 1 << buffer;
+
+      decl |= buffer << SO_DECL_OUTPUT_BUFFER_SLOT_SHIFT;
+      decl |= vue_map->vert_result_to_slot[vert_result] <<
+	 SO_DECL_REGISTER_INDEX_SHIFT;
+      decl |= ((1 << linked_xfb_info->Outputs[i].NumComponents) - 1) <<
+	 SO_DECL_COMPONENT_MASK_SHIFT;
+
+      /* This assert should be true until GL_ARB_transform_feedback_instanced
+       * is added and we start using the hole flag.
+       */
+      assert(linked_xfb_info->Outputs[i].DstOffset == next_offset[buffer]);
+
+      next_offset[buffer] += linked_xfb_info->Outputs[i].NumComponents;
+
+      so_decl[i] = decl;
+   }
+
+   BEGIN_BATCH(linked_xfb_info->NumOutputs * 2 + 3);
+   OUT_BATCH(_3DSTATE_SO_DECL_LIST << 16 |
+	     (linked_xfb_info->NumOutputs * 2 + 1));
+
+   OUT_BATCH((buffer_mask << SO_STREAM_TO_BUFFER_SELECTS_0_SHIFT) |
+	     (0 << SO_STREAM_TO_BUFFER_SELECTS_1_SHIFT) |
+	     (0 << SO_STREAM_TO_BUFFER_SELECTS_2_SHIFT) |
+	     (0 << SO_STREAM_TO_BUFFER_SELECTS_3_SHIFT));
+
+   OUT_BATCH((linked_xfb_info->NumOutputs << SO_NUM_ENTRIES_0_SHIFT) |
+	     (0 << SO_NUM_ENTRIES_1_SHIFT) |
+	     (0 << SO_NUM_ENTRIES_2_SHIFT) |
+	     (0 << SO_NUM_ENTRIES_3_SHIFT));
+
+   for (i = 0; i < linked_xfb_info->NumOutputs; i++) {
+      OUT_BATCH(so_decl[i]);
+      OUT_BATCH(0);
+   }
+
+   ADVANCE_BATCH();
+}
+
+static void
+upload_3dstate_streamout(struct brw_context *brw, bool active,
+			 struct brw_vue_map *vue_map)
+{
+   struct intel_context *intel = &brw->intel;
+   struct gl_context *ctx = &intel->ctx;
+   /* _NEW_TRANSFORM_FEEDBACK */
+   struct gl_transform_feedback_object *xfb_obj =
+      ctx->TransformFeedback.CurrentObject;
+   uint32_t dw1 = 0, dw2 = 0;
+   int i;
+
+   /* _NEW_RASTERIZER_DISCARD */
+   if (ctx->RasterDiscard)
+      dw1 |= SO_RENDERING_DISABLE;
+
+   if (active) {
+      int urb_entry_read_offset = 0;
+      int urb_entry_read_length = (vue_map->num_slots + 1) / 2 -
+	 urb_entry_read_offset;
+
+      dw1 |= SO_FUNCTION_ENABLE;
+      dw1 |= SO_STATISTICS_ENABLE;
+
+      for (i = 0; i < 4; i++) {
+	 if (xfb_obj->Buffers[i]) {
+	    dw1 |= SO_BUFFER_ENABLE(i);
+	 }
+      }
+
+      /* We always read the whole vertex.  This could be reduced at some
+       * point by reading less and offsetting the register index in the
+       * SO_DECLs.
+       */
+      dw2 |= urb_entry_read_offset << SO_STREAM_0_VERTEX_READ_OFFSET_SHIFT;
+      dw2 |= (urb_entry_read_length - 1) <<
+	 SO_STREAM_0_VERTEX_READ_LENGTH_SHIFT;
+   }
 
-   /* Disable the SOL stage */
    BEGIN_BATCH(3);
    OUT_BATCH(_3DSTATE_STREAMOUT << 16 | (3 - 2));
-   OUT_BATCH(0);
-   OUT_BATCH(0);
+   OUT_BATCH(dw1);
+   OUT_BATCH(dw2);
    ADVANCE_BATCH();
 }
 
+static void
+upload_sol_state(struct brw_context *brw)
+{
+   struct intel_context *intel = &brw->intel;
+   struct gl_context *ctx = &intel->ctx;
+   /* _NEW_TRANSFORM_FEEDBACK */
+   struct gl_transform_feedback_object *xfb_obj =
+      ctx->TransformFeedback.CurrentObject;
+   bool active = xfb_obj->Active && !xfb_obj->Paused;
+   struct brw_vue_map vue_map;
+
+   /* _NEW_TRANSFORM, CACHE_NEW_VS_PROG */
+   brw_compute_vue_map(&vue_map, intel, ctx->Transform.ClipPlanesEnabled != 0,
+                       brw->vs.prog_data->outputs_written);
+
+   if (active) {
+      upload_3dstate_so_buffers(brw);
+      upload_3dstate_so_decl_list(brw, &vue_map);
+   }
+
+   /* Finally, set up the SOL stage.  This command must always follow updates to
+    * the nonpipelined SOL state (3DSTATE_SO_BUFFER, 3DSTATE_SO_DECL_LIST) or
+    * MMIO register updates (current performed by the kernel at each batch
+    * emit).
+    */
+   upload_3dstate_streamout(brw, active, &vue_map);
+}
+
 const struct brw_tracked_state gen7_sol_state = {
    .dirty = {
-      .mesa  = 0,
-      .brw   = BRW_NEW_BATCH,
-      .cache = 0,
+      .mesa  = (_NEW_RASTERIZER_DISCARD |
+		_NEW_TRANSFORM_FEEDBACK |
+		_NEW_TRANSFORM),
+      .brw   = (BRW_NEW_BATCH |
+		BRW_NEW_VERTEX_PROGRAM),
+      .cache = CACHE_NEW_VS_PROG,
    },
    .emit = upload_sol_state,
 };