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/*
* Copyright © 2016 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
/**
* An implementation of the transform feedback driver hooks for Haswell
* and later hardware. This uses MI_MATH to compute the number of vertices
* written (for use by DrawTransformFeedback()) without any CPU<->GPU
* synchronization which could stall.
*/
#include "brw_context.h"
#include "brw_state.h"
#include "brw_defines.h"
#include "intel_batchbuffer.h"
#include "intel_buffer_objects.h"
#include "main/transformfeedback.h"
/**
* We store several values in obj->prim_count_bo:
*
* [4x 32-bit values]: Final Number of Vertices Written
* [4x 32-bit values]: Tally of Primitives Written So Far
* [4x 64-bit values]: Starting SO_NUM_PRIMS_WRITTEN Counter Snapshots
*
* The first set of values is used by DrawTransformFeedback(), which
* copies one of them into the 3DPRIM_VERTEX_COUNT register and performs
* an indirect draw. The other values are just temporary storage.
*/
#define TALLY_OFFSET (BRW_MAX_XFB_STREAMS * sizeof(uint32_t))
#define START_OFFSET (TALLY_OFFSET * 2)
/**
* Store the SO_NUM_PRIMS_WRITTEN counters for each stream (4 uint64_t values)
* to prim_count_bo.
*/
static void
save_prim_start_values(struct brw_context *brw,
struct brw_transform_feedback_object *obj)
{
/* Flush any drawing so that the counters have the right values. */
brw_emit_mi_flush(brw);
/* Emit MI_STORE_REGISTER_MEM commands to write the values. */
for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
brw_store_register_mem64(brw, obj->prim_count_bo,
GEN7_SO_NUM_PRIMS_WRITTEN(i),
START_OFFSET + i * sizeof(uint64_t));
}
}
/**
* Compute the number of primitives written during our most recent
* transform feedback activity (the current SO_NUM_PRIMS_WRITTEN value
* minus the stashed "start" value), and add it to our running tally.
*
* If \p finalize is true, also compute the number of vertices written
* (by multiplying by the number of vertices per primitive), and store
* that to the "final" location.
*
* Otherwise, just overwrite the old tally with the new one.
*/
static void
tally_prims_written(struct brw_context *brw,
struct brw_transform_feedback_object *obj,
bool finalize)
{
/* Flush any drawing so that the counters have the right values. */
brw_emit_mi_flush(brw);
for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
/* GPR0 = Tally */
brw_load_register_imm32(brw, HSW_CS_GPR(0) + 4, 0);
brw_load_register_mem(brw, HSW_CS_GPR(0), obj->prim_count_bo,
I915_GEM_DOMAIN_INSTRUCTION,
I915_GEM_DOMAIN_INSTRUCTION,
TALLY_OFFSET + i * sizeof(uint32_t));
if (!obj->base.Paused) {
/* GPR1 = Start Snapshot */
brw_load_register_mem64(brw, HSW_CS_GPR(1), obj->prim_count_bo,
I915_GEM_DOMAIN_INSTRUCTION,
I915_GEM_DOMAIN_INSTRUCTION,
START_OFFSET + i * sizeof(uint64_t));
/* GPR2 = Ending Snapshot */
brw_load_register_reg64(brw, GEN7_SO_NUM_PRIMS_WRITTEN(i), HSW_CS_GPR(2));
BEGIN_BATCH(9);
OUT_BATCH(HSW_MI_MATH | (9 - 2));
/* GPR1 = GPR2 (End) - GPR1 (Start) */
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R2));
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R1));
OUT_BATCH(MI_MATH_ALU0(SUB));
OUT_BATCH(MI_MATH_ALU2(STORE, R1, ACCU));
/* GPR0 = GPR0 (Tally) + GPR1 (Diff) */
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R0));
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R1));
OUT_BATCH(MI_MATH_ALU0(ADD));
OUT_BATCH(MI_MATH_ALU2(STORE, R0, ACCU));
ADVANCE_BATCH();
}
if (!finalize) {
/* Write back the new tally */
brw_store_register_mem32(brw, obj->prim_count_bo, HSW_CS_GPR(0),
TALLY_OFFSET + i * sizeof(uint32_t));
} else {
/* Convert the number of primitives to the number of vertices. */
if (obj->primitive_mode == GL_LINES) {
/* Double R0 (R0 = R0 + R0) */
BEGIN_BATCH(5);
OUT_BATCH(HSW_MI_MATH | (5 - 2));
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R0));
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R0));
OUT_BATCH(MI_MATH_ALU0(ADD));
OUT_BATCH(MI_MATH_ALU2(STORE, R0, ACCU));
ADVANCE_BATCH();
} else if (obj->primitive_mode == GL_TRIANGLES) {
/* Triple R0 (R1 = R0 + R0, R0 = R0 + R1) */
BEGIN_BATCH(9);
OUT_BATCH(HSW_MI_MATH | (9 - 2));
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R0));
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R0));
OUT_BATCH(MI_MATH_ALU0(ADD));
OUT_BATCH(MI_MATH_ALU2(STORE, R1, ACCU));
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R0));
OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R1));
OUT_BATCH(MI_MATH_ALU0(ADD));
OUT_BATCH(MI_MATH_ALU2(STORE, R0, ACCU));
ADVANCE_BATCH();
}
/* Store it to the final result */
brw_store_register_mem32(brw, obj->prim_count_bo, HSW_CS_GPR(0),
i * sizeof(uint32_t));
}
}
}
/**
* BeginTransformFeedback() driver hook.
*/
void
hsw_begin_transform_feedback(struct gl_context *ctx, GLenum mode,
struct gl_transform_feedback_object *obj)
{
struct brw_context *brw = brw_context(ctx);
struct brw_transform_feedback_object *brw_obj =
(struct brw_transform_feedback_object *) obj;
brw_obj->primitive_mode = mode;
/* Reset the SO buffer offsets to 0. */
if (brw->gen >= 8) {
brw_obj->zero_offsets = true;
} else {
BEGIN_BATCH(1 + 2 * BRW_MAX_XFB_STREAMS);
OUT_BATCH(MI_LOAD_REGISTER_IMM | (1 + 2 * BRW_MAX_XFB_STREAMS - 2));
for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
OUT_BATCH(0);
}
ADVANCE_BATCH();
}
/* Zero out the initial tallies */
brw_store_data_imm64(brw, brw_obj->prim_count_bo, TALLY_OFFSET, 0ull);
brw_store_data_imm64(brw, brw_obj->prim_count_bo, TALLY_OFFSET + 8, 0ull);
/* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
save_prim_start_values(brw, brw_obj);
}
/**
* PauseTransformFeedback() driver hook.
*/
void
hsw_pause_transform_feedback(struct gl_context *ctx,
struct gl_transform_feedback_object *obj)
{
struct brw_context *brw = brw_context(ctx);
struct brw_transform_feedback_object *brw_obj =
(struct brw_transform_feedback_object *) obj;
if (brw->is_haswell) {
/* Save the SOL buffer offset register values. */
for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
BEGIN_BATCH(3);
OUT_BATCH(MI_STORE_REGISTER_MEM | (3 - 2));
OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
OUT_RELOC(brw_obj->offset_bo,
I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
i * sizeof(uint32_t));
ADVANCE_BATCH();
}
}
/* Add any primitives written to our tally */
tally_prims_written(brw, brw_obj, false);
}
/**
* ResumeTransformFeedback() driver hook.
*/
void
hsw_resume_transform_feedback(struct gl_context *ctx,
struct gl_transform_feedback_object *obj)
{
struct brw_context *brw = brw_context(ctx);
struct brw_transform_feedback_object *brw_obj =
(struct brw_transform_feedback_object *) obj;
if (brw->is_haswell) {
/* Reload the SOL buffer offset registers. */
for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
BEGIN_BATCH(3);
OUT_BATCH(GEN7_MI_LOAD_REGISTER_MEM | (3 - 2));
OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
OUT_RELOC(brw_obj->offset_bo,
I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
i * sizeof(uint32_t));
ADVANCE_BATCH();
}
}
/* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
save_prim_start_values(brw, brw_obj);
}
/**
* EndTransformFeedback() driver hook.
*/
void
hsw_end_transform_feedback(struct gl_context *ctx,
struct gl_transform_feedback_object *obj)
{
struct brw_context *brw = brw_context(ctx);
struct brw_transform_feedback_object *brw_obj =
(struct brw_transform_feedback_object *) obj;
/* Add any primitives written to our tally, convert it from the number
* of primitives written to the number of vertices written, and store
* it in the "final" location in the buffer which DrawTransformFeedback()
* will use as the vertex count.
*/
tally_prims_written(brw, brw_obj, true);
}
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