1 /*
2 * Copyright © 2016 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24 /**
25 * An implementation of the transform feedback driver hooks for Haswell
26 * and later hardware. This uses MI_MATH to compute the number of vertices
27 * written (for use by DrawTransformFeedback()) without any CPU<->GPU
28 * synchronization which could stall.
29 */
30
31 #include "brw_context.h"
32 #include "brw_state.h"
33 #include "brw_defines.h"
34 #include "intel_batchbuffer.h"
35 #include "intel_buffer_objects.h"
36 #include "main/transformfeedback.h"
37
38 /**
39 * We store several values in obj->prim_count_bo:
40 *
41 * [4x 32-bit values]: Final Number of Vertices Written
42 * [4x 32-bit values]: Tally of Primitives Written So Far
43 * [4x 64-bit values]: Starting SO_NUM_PRIMS_WRITTEN Counter Snapshots
44 *
45 * The first set of values is used by DrawTransformFeedback(), which
46 * copies one of them into the 3DPRIM_VERTEX_COUNT register and performs
47 * an indirect draw. The other values are just temporary storage.
48 */
49
50 #define TALLY_OFFSET (BRW_MAX_XFB_STREAMS * sizeof(uint32_t))
51 #define START_OFFSET (TALLY_OFFSET * 2)
52
53 /**
54 * Store the SO_NUM_PRIMS_WRITTEN counters for each stream (4 uint64_t values)
55 * to prim_count_bo.
56 */
57 static void
save_prim_start_values(struct brw_context * brw,struct brw_transform_feedback_object * obj)58 save_prim_start_values(struct brw_context *brw,
59 struct brw_transform_feedback_object *obj)
60 {
61 /* Flush any drawing so that the counters have the right values. */
62 brw_emit_mi_flush(brw);
63
64 /* Emit MI_STORE_REGISTER_MEM commands to write the values. */
65 for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
66 brw_store_register_mem64(brw, obj->prim_count_bo,
67 GEN7_SO_NUM_PRIMS_WRITTEN(i),
68 START_OFFSET + i * sizeof(uint64_t));
69 }
70 }
71
72 /**
73 * Compute the number of primitives written during our most recent
74 * transform feedback activity (the current SO_NUM_PRIMS_WRITTEN value
75 * minus the stashed "start" value), and add it to our running tally.
76 *
77 * If \p finalize is true, also compute the number of vertices written
78 * (by multiplying by the number of vertices per primitive), and store
79 * that to the "final" location.
80 *
81 * Otherwise, just overwrite the old tally with the new one.
82 */
83 static void
tally_prims_written(struct brw_context * brw,struct brw_transform_feedback_object * obj,bool finalize)84 tally_prims_written(struct brw_context *brw,
85 struct brw_transform_feedback_object *obj,
86 bool finalize)
87 {
88 /* Flush any drawing so that the counters have the right values. */
89 brw_emit_mi_flush(brw);
90
91 for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
92 /* GPR0 = Tally */
93 brw_load_register_imm32(brw, HSW_CS_GPR(0) + 4, 0);
94 brw_load_register_mem(brw, HSW_CS_GPR(0), obj->prim_count_bo,
95 I915_GEM_DOMAIN_INSTRUCTION,
96 I915_GEM_DOMAIN_INSTRUCTION,
97 TALLY_OFFSET + i * sizeof(uint32_t));
98 if (!obj->base.Paused) {
99 /* GPR1 = Start Snapshot */
100 brw_load_register_mem64(brw, HSW_CS_GPR(1), obj->prim_count_bo,
101 I915_GEM_DOMAIN_INSTRUCTION,
102 I915_GEM_DOMAIN_INSTRUCTION,
103 START_OFFSET + i * sizeof(uint64_t));
104 /* GPR2 = Ending Snapshot */
105 brw_load_register_reg64(brw, GEN7_SO_NUM_PRIMS_WRITTEN(i), HSW_CS_GPR(2));
106
107 BEGIN_BATCH(9);
108 OUT_BATCH(HSW_MI_MATH | (9 - 2));
109 /* GPR1 = GPR2 (End) - GPR1 (Start) */
110 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R2));
111 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R1));
112 OUT_BATCH(MI_MATH_ALU0(SUB));
113 OUT_BATCH(MI_MATH_ALU2(STORE, R1, ACCU));
114 /* GPR0 = GPR0 (Tally) + GPR1 (Diff) */
115 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R0));
116 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R1));
117 OUT_BATCH(MI_MATH_ALU0(ADD));
118 OUT_BATCH(MI_MATH_ALU2(STORE, R0, ACCU));
119 ADVANCE_BATCH();
120 }
121
122 if (!finalize) {
123 /* Write back the new tally */
124 brw_store_register_mem32(brw, obj->prim_count_bo, HSW_CS_GPR(0),
125 TALLY_OFFSET + i * sizeof(uint32_t));
126 } else {
127 /* Convert the number of primitives to the number of vertices. */
128 if (obj->primitive_mode == GL_LINES) {
129 /* Double R0 (R0 = R0 + R0) */
130 BEGIN_BATCH(5);
131 OUT_BATCH(HSW_MI_MATH | (5 - 2));
132 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R0));
133 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R0));
134 OUT_BATCH(MI_MATH_ALU0(ADD));
135 OUT_BATCH(MI_MATH_ALU2(STORE, R0, ACCU));
136 ADVANCE_BATCH();
137 } else if (obj->primitive_mode == GL_TRIANGLES) {
138 /* Triple R0 (R1 = R0 + R0, R0 = R0 + R1) */
139 BEGIN_BATCH(9);
140 OUT_BATCH(HSW_MI_MATH | (9 - 2));
141 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R0));
142 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R0));
143 OUT_BATCH(MI_MATH_ALU0(ADD));
144 OUT_BATCH(MI_MATH_ALU2(STORE, R1, ACCU));
145 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCA, R0));
146 OUT_BATCH(MI_MATH_ALU2(LOAD, SRCB, R1));
147 OUT_BATCH(MI_MATH_ALU0(ADD));
148 OUT_BATCH(MI_MATH_ALU2(STORE, R0, ACCU));
149 ADVANCE_BATCH();
150 }
151 /* Store it to the final result */
152 brw_store_register_mem32(brw, obj->prim_count_bo, HSW_CS_GPR(0),
153 i * sizeof(uint32_t));
154 }
155 }
156 }
157
158 /**
159 * BeginTransformFeedback() driver hook.
160 */
161 void
hsw_begin_transform_feedback(struct gl_context * ctx,GLenum mode,struct gl_transform_feedback_object * obj)162 hsw_begin_transform_feedback(struct gl_context *ctx, GLenum mode,
163 struct gl_transform_feedback_object *obj)
164 {
165 struct brw_context *brw = brw_context(ctx);
166 struct brw_transform_feedback_object *brw_obj =
167 (struct brw_transform_feedback_object *) obj;
168
169 brw_obj->primitive_mode = mode;
170
171 /* Reset the SO buffer offsets to 0. */
172 if (brw->gen >= 8) {
173 brw_obj->zero_offsets = true;
174 } else {
175 BEGIN_BATCH(1 + 2 * BRW_MAX_XFB_STREAMS);
176 OUT_BATCH(MI_LOAD_REGISTER_IMM | (1 + 2 * BRW_MAX_XFB_STREAMS - 2));
177 for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
178 OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
179 OUT_BATCH(0);
180 }
181 ADVANCE_BATCH();
182 }
183
184 /* Zero out the initial tallies */
185 brw_store_data_imm64(brw, brw_obj->prim_count_bo, TALLY_OFFSET, 0ull);
186 brw_store_data_imm64(brw, brw_obj->prim_count_bo, TALLY_OFFSET + 8, 0ull);
187
188 /* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
189 save_prim_start_values(brw, brw_obj);
190 }
191
192 /**
193 * PauseTransformFeedback() driver hook.
194 */
195 void
hsw_pause_transform_feedback(struct gl_context * ctx,struct gl_transform_feedback_object * obj)196 hsw_pause_transform_feedback(struct gl_context *ctx,
197 struct gl_transform_feedback_object *obj)
198 {
199 struct brw_context *brw = brw_context(ctx);
200 struct brw_transform_feedback_object *brw_obj =
201 (struct brw_transform_feedback_object *) obj;
202
203 if (brw->is_haswell) {
204 /* Flush any drawing so that the counters have the right values. */
205 brw_emit_mi_flush(brw);
206
207 /* Save the SOL buffer offset register values. */
208 for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
209 BEGIN_BATCH(3);
210 OUT_BATCH(MI_STORE_REGISTER_MEM | (3 - 2));
211 OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
212 OUT_RELOC(brw_obj->offset_bo,
213 I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
214 i * sizeof(uint32_t));
215 ADVANCE_BATCH();
216 }
217 }
218
219 /* Add any primitives written to our tally */
220 tally_prims_written(brw, brw_obj, false);
221 }
222
223 /**
224 * ResumeTransformFeedback() driver hook.
225 */
226 void
hsw_resume_transform_feedback(struct gl_context * ctx,struct gl_transform_feedback_object * obj)227 hsw_resume_transform_feedback(struct gl_context *ctx,
228 struct gl_transform_feedback_object *obj)
229 {
230 struct brw_context *brw = brw_context(ctx);
231 struct brw_transform_feedback_object *brw_obj =
232 (struct brw_transform_feedback_object *) obj;
233
234 if (brw->is_haswell) {
235 /* Reload the SOL buffer offset registers. */
236 for (int i = 0; i < BRW_MAX_XFB_STREAMS; i++) {
237 BEGIN_BATCH(3);
238 OUT_BATCH(GEN7_MI_LOAD_REGISTER_MEM | (3 - 2));
239 OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
240 OUT_RELOC(brw_obj->offset_bo,
241 I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
242 i * sizeof(uint32_t));
243 ADVANCE_BATCH();
244 }
245 }
246
247 /* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
248 save_prim_start_values(brw, brw_obj);
249 }
250
251 /**
252 * EndTransformFeedback() driver hook.
253 */
254 void
hsw_end_transform_feedback(struct gl_context * ctx,struct gl_transform_feedback_object * obj)255 hsw_end_transform_feedback(struct gl_context *ctx,
256 struct gl_transform_feedback_object *obj)
257 {
258 struct brw_context *brw = brw_context(ctx);
259 struct brw_transform_feedback_object *brw_obj =
260 (struct brw_transform_feedback_object *) obj;
261
262 /* Add any primitives written to our tally, convert it from the number
263 * of primitives written to the number of vertices written, and store
264 * it in the "final" location in the buffer which DrawTransformFeedback()
265 * will use as the vertex count.
266 */
267 tally_prims_written(brw, brw_obj, true);
268 }
269