[Mesa-dev] [PATCH 4/5] i965: Implement interface to edit binding table entries

[Abdiel Janulgue]

Unlike normal software binding tables where the driver has to manually
generate and fill a binding table array which are then uploaded to the
hardware, the resource streamer instead presents the driver with an option
to fill out slots for individual binding table indices. The hardware
accumlates the state for these combined edits which it then automatically
flushes to a binding table pool when the binding table pointer state
command is invoked.

Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
---
 src/mesa/drivers/dri/i965/brw_binding_tables.c | 50 ++++++++++++++++++++++++++
 src/mesa/drivers/dri/i965/brw_state.h          |  9 +++++
 2 files changed, 59 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_binding_tables.c b/src/mesa/drivers/dri/i965/brw_binding_tables.c
index d8cb96d..e0ee700 100644
--- a/src/mesa/drivers/dri/i965/brw_binding_tables.c
+++ b/src/mesa/drivers/dri/i965/brw_binding_tables.c
@@ -61,6 +61,12 @@
  */
 #define HW_BT_START_OFFSET 2 * 256;
 
+static const GLuint stage_to_bt_edit[MESA_SHADER_FRAGMENT + 1] = {
+   _3DSTATE_BINDING_TABLE_EDIT_VS,
+   _3DSTATE_BINDING_TABLE_EDIT_GS,
+   _3DSTATE_BINDING_TABLE_EDIT_PS,
+};
+
 /**
  * Upload a shader stage's binding table as indirect state.
  *
@@ -191,6 +197,50 @@ const struct brw_tracked_state brw_gs_binding_table = {
  * Hardware-generated binding tables for the resource streamer
  */
 void
+gen7_update_binding_table(struct brw_context *brw,
+                          gl_shader_stage stage,
+                          uint32_t index,
+                          uint32_t surf_offset)
+{
+   assert(stage <= MESA_SHADER_FRAGMENT);
+
+   /* The surface state offset is a 16-bit value aligned to 32 bytes but
+    * Surface State Pointer in dw2 is [15:0]. Right shift surf_offset
+    * by 5 bits so it won't disturb bit 16 (which is used as the binding
+    * table index entry), otherwise it would hang the GPU.
+    */
+   uint32_t dw2 = SET_FIELD(index, BRW_BINDING_TABLE_INDEX) | (surf_offset >> 5);
+
+   BEGIN_BATCH(3);
+   OUT_BATCH(stage_to_bt_edit[stage] << 16 | (3 - 2));
+   OUT_BATCH(BRW_BINDING_TABLE_EDIT_TARGET_ALL);
+   OUT_BATCH(dw2);
+   ADVANCE_BATCH();
+}
+
+/**
+ * Hardware-generated binding tables for the resource streamer
+ */
+void
+gen7_update_binding_table_from_array(struct brw_context *brw,
+                                     gl_shader_stage stage,
+                                     const uint32_t* binding_table,
+                                     int size)
+{
+   uint32_t dw2 = 0;
+   assert(stage <= MESA_SHADER_FRAGMENT);
+
+   BEGIN_BATCH(size + 2);
+   OUT_BATCH(stage_to_bt_edit[stage] << 16 | size);
+   OUT_BATCH(BRW_BINDING_TABLE_EDIT_TARGET_ALL);
+   for (int i = 0; i < size; i++) {
+      dw2 = SET_FIELD(i, BRW_BINDING_TABLE_INDEX) | (binding_table[i] >> 5);
+      OUT_BATCH(dw2);
+   }
+   ADVANCE_BATCH();
+}
+
+void
 gen7_disable_hw_binding_tables(struct brw_context *brw)
 {
    BEGIN_BATCH(3);
diff --git a/src/mesa/drivers/dri/i965/brw_state.h b/src/mesa/drivers/dri/i965/brw_state.h
index 52dea58..b296e54 100644
--- a/src/mesa/drivers/dri/i965/brw_state.h
+++ b/src/mesa/drivers/dri/i965/brw_state.h
@@ -375,6 +375,15 @@ gen7_upload_constant_state(struct brw_context *brw,
 
 /* gen7_misc_state.c */
 void gen7_rs_control(struct brw_context *brw, int enable);
+
+void gen7_update_binding_table(struct brw_context *brw,
+                               gl_shader_stage stage,
+                               uint32_t index,
+                               uint32_t surf_offset);
+void gen7_update_binding_table_from_array(struct brw_context *brw,
+                                          gl_shader_stage stage,
+                                          const uint32_t* binding_table,
+                                          int size);
 void gen7_enable_hw_binding_tables(struct brw_context *brw);
 void gen7_disable_hw_binding_tables(struct brw_context *brw);
 void gen7_reset_rs_pool_offsets(struct brw_context *brw);
-- 
1.9.1