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1 /*
2  * Copyright © 2011 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 /** \file gen6_sol.c
25  *
26  * Code to initialize the binding table entries used by transform feedback.
27  */
28 
29 #include "main/bufferobj.h"
30 #include "main/macros.h"
31 #include "brw_context.h"
32 #include "intel_batchbuffer.h"
33 #include "brw_defines.h"
34 #include "brw_state.h"
35 #include "main/transformfeedback.h"
36 
37 static void
gen6_update_sol_surfaces(struct brw_context * brw)38 gen6_update_sol_surfaces(struct brw_context *brw)
39 {
40    struct gl_context *ctx = &brw->ctx;
41    bool xfb_active = _mesa_is_xfb_active_and_unpaused(ctx);
42    struct gl_transform_feedback_object *xfb_obj;
43    const struct gl_transform_feedback_info *linked_xfb_info = NULL;
44 
45    if (xfb_active) {
46       /* BRW_NEW_TRANSFORM_FEEDBACK */
47       xfb_obj = ctx->TransformFeedback.CurrentObject;
48       linked_xfb_info = xfb_obj->program->sh.LinkedTransformFeedback;
49    }
50 
51    for (int i = 0; i < BRW_MAX_SOL_BINDINGS; ++i) {
52       const int surf_index = BRW_GEN6_SOL_BINDING_START + i;
53       if (xfb_active && i < linked_xfb_info->NumOutputs) {
54          unsigned buffer = linked_xfb_info->Outputs[i].OutputBuffer;
55          unsigned buffer_offset =
56             xfb_obj->Offset[buffer] / 4 +
57             linked_xfb_info->Outputs[i].DstOffset;
58          if (brw->programs[MESA_SHADER_GEOMETRY]) {
59             brw_update_sol_surface(
60                brw, xfb_obj->Buffers[buffer],
61                &brw->gs.base.surf_offset[surf_index],
62                linked_xfb_info->Outputs[i].NumComponents,
63                linked_xfb_info->Buffers[buffer].Stride, buffer_offset);
64          } else {
65             brw_update_sol_surface(
66                brw, xfb_obj->Buffers[buffer],
67                &brw->ff_gs.surf_offset[surf_index],
68                linked_xfb_info->Outputs[i].NumComponents,
69                linked_xfb_info->Buffers[buffer].Stride, buffer_offset);
70          }
71       } else {
72          if (!brw->programs[MESA_SHADER_GEOMETRY])
73             brw->ff_gs.surf_offset[surf_index] = 0;
74          else
75             brw->gs.base.surf_offset[surf_index] = 0;
76       }
77    }
78 
79    brw->ctx.NewDriverState |= BRW_NEW_SURFACES;
80 }
81 
82 const struct brw_tracked_state gen6_sol_surface = {
83    .dirty = {
84       .mesa = 0,
85       .brw = BRW_NEW_BATCH |
86              BRW_NEW_BLORP |
87              BRW_NEW_TRANSFORM_FEEDBACK,
88    },
89    .emit = gen6_update_sol_surfaces,
90 };
91 
92 /**
93  * Constructs the binding table for the WM surface state, which maps unit
94  * numbers to surface state objects.
95  */
96 static void
brw_gs_upload_binding_table(struct brw_context * brw)97 brw_gs_upload_binding_table(struct brw_context *brw)
98 {
99    uint32_t *bind;
100    struct gl_context *ctx = &brw->ctx;
101    const struct gl_program *prog;
102    bool need_binding_table = false;
103 
104    /* We have two scenarios here:
105     * 1) We are using a geometry shader only to implement transform feedback
106     *    for a vertex shader (brw->programs[MESA_SHADER_GEOMETRY] == NULL).
107     *    In this case, we only need surfaces for transform feedback in the
108     *    GS stage.
109     * 2) We have a user-provided geometry shader. In this case we may need
110     *    surfaces for transform feedback and/or other stuff, like textures,
111     *    in the GS stage.
112     */
113 
114    if (!brw->programs[MESA_SHADER_GEOMETRY]) {
115       /* BRW_NEW_VERTEX_PROGRAM */
116       prog = ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX];
117       if (prog) {
118          /* Skip making a binding table if we don't have anything to put in it */
119          const struct gl_transform_feedback_info *linked_xfb_info =
120             prog->sh.LinkedTransformFeedback;
121          need_binding_table = linked_xfb_info->NumOutputs > 0;
122       }
123       if (!need_binding_table) {
124          if (brw->ff_gs.bind_bo_offset != 0) {
125             brw->ctx.NewDriverState |= BRW_NEW_BINDING_TABLE_POINTERS;
126             brw->ff_gs.bind_bo_offset = 0;
127          }
128          return;
129       }
130 
131       /* Might want to calculate nr_surfaces first, to avoid taking up so much
132        * space for the binding table. Anyway, in this case we know that we only
133        * use BRW_MAX_SOL_BINDINGS surfaces at most.
134        */
135       bind = brw_state_batch(brw, sizeof(uint32_t) * BRW_MAX_SOL_BINDINGS,
136                              32, &brw->ff_gs.bind_bo_offset);
137 
138       /* BRW_NEW_SURFACES */
139       memcpy(bind, brw->ff_gs.surf_offset,
140              BRW_MAX_SOL_BINDINGS * sizeof(uint32_t));
141    } else {
142       /* BRW_NEW_GEOMETRY_PROGRAM */
143       prog = ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY];
144       if (prog) {
145          /* Skip making a binding table if we don't have anything to put in it */
146          struct brw_stage_prog_data *prog_data = brw->gs.base.prog_data;
147          const struct gl_transform_feedback_info *linked_xfb_info =
148             prog->sh.LinkedTransformFeedback;
149          need_binding_table = linked_xfb_info->NumOutputs > 0 ||
150                               prog_data->binding_table.size_bytes > 0;
151       }
152       if (!need_binding_table) {
153          if (brw->gs.base.bind_bo_offset != 0) {
154             brw->gs.base.bind_bo_offset = 0;
155             brw->ctx.NewDriverState |= BRW_NEW_BINDING_TABLE_POINTERS;
156          }
157          return;
158       }
159 
160       /* Might want to calculate nr_surfaces first, to avoid taking up so much
161        * space for the binding table.
162        */
163       bind = brw_state_batch(brw, sizeof(uint32_t) * BRW_MAX_SURFACES,
164                              32, &brw->gs.base.bind_bo_offset);
165 
166       /* BRW_NEW_SURFACES */
167       memcpy(bind, brw->gs.base.surf_offset,
168              BRW_MAX_SURFACES * sizeof(uint32_t));
169    }
170 
171    brw->ctx.NewDriverState |= BRW_NEW_BINDING_TABLE_POINTERS;
172 }
173 
174 const struct brw_tracked_state gen6_gs_binding_table = {
175    .dirty = {
176       .mesa = 0,
177       .brw = BRW_NEW_BATCH |
178              BRW_NEW_BLORP |
179              BRW_NEW_GEOMETRY_PROGRAM |
180              BRW_NEW_VERTEX_PROGRAM |
181              BRW_NEW_SURFACES,
182    },
183    .emit = brw_gs_upload_binding_table,
184 };
185 
186 struct gl_transform_feedback_object *
brw_new_transform_feedback(struct gl_context * ctx,GLuint name)187 brw_new_transform_feedback(struct gl_context *ctx, GLuint name)
188 {
189    struct brw_context *brw = brw_context(ctx);
190    struct brw_transform_feedback_object *brw_obj =
191       CALLOC_STRUCT(brw_transform_feedback_object);
192    if (!brw_obj)
193       return NULL;
194 
195    _mesa_init_transform_feedback_object(&brw_obj->base, name);
196 
197    brw_obj->offset_bo =
198       brw_bo_alloc(brw->bufmgr, "transform feedback offsets", 16, 64);
199    brw_obj->prim_count_bo =
200       brw_bo_alloc(brw->bufmgr, "xfb primitive counts", 16384, 64);
201 
202    return &brw_obj->base;
203 }
204 
205 void
brw_delete_transform_feedback(struct gl_context * ctx,struct gl_transform_feedback_object * obj)206 brw_delete_transform_feedback(struct gl_context *ctx,
207                               struct gl_transform_feedback_object *obj)
208 {
209    struct brw_transform_feedback_object *brw_obj =
210       (struct brw_transform_feedback_object *) obj;
211 
212    for (unsigned i = 0; i < ARRAY_SIZE(obj->Buffers); i++) {
213       _mesa_reference_buffer_object(ctx, &obj->Buffers[i], NULL);
214    }
215 
216    brw_bo_unreference(brw_obj->offset_bo);
217    brw_bo_unreference(brw_obj->prim_count_bo);
218 
219    free(brw_obj);
220 }
221 
222 /**
223  * Tally the number of primitives generated so far.
224  *
225  * The buffer contains a series of pairs:
226  * (<start0, start1, start2, start3>, <end0, end1, end2, end3>) ;
227  * (<start0, start1, start2, start3>, <end0, end1, end2, end3>) ;
228  *
229  * For each stream, we subtract the pair of values (end - start) to get the
230  * number of primitives generated during one section.  We accumulate these
231  * values, adding them up to get the total number of primitives generated.
232  *
233  * Note that we expose one stream pre-Gen7, so the above is just (start, end).
234  */
235 static void
aggregate_transform_feedback_counter(struct brw_context * brw,struct brw_bo * bo,struct brw_transform_feedback_counter * counter)236 aggregate_transform_feedback_counter(
237    struct brw_context *brw,
238    struct brw_bo *bo,
239    struct brw_transform_feedback_counter *counter)
240 {
241    const unsigned streams = brw->ctx.Const.MaxVertexStreams;
242 
243    /* If the current batch is still contributing to the number of primitives
244     * generated, flush it now so the results will be present when mapped.
245     */
246    if (brw_batch_references(&brw->batch, bo))
247       intel_batchbuffer_flush(brw);
248 
249    if (unlikely(brw->perf_debug && brw_bo_busy(bo)))
250       perf_debug("Stalling for # of transform feedback primitives written.\n");
251 
252    uint64_t *prim_counts = brw_bo_map(brw, bo, MAP_READ);
253    prim_counts += counter->bo_start * streams;
254 
255    for (unsigned i = counter->bo_start; i + 1 < counter->bo_end; i += 2) {
256       for (unsigned s = 0; s < streams; s++)
257          counter->accum[s] += prim_counts[streams + s] - prim_counts[s];
258 
259       prim_counts += 2 * streams;
260    }
261 
262    brw_bo_unmap(bo);
263 
264    /* We've already gathered up the old data; we can safely overwrite it now. */
265    counter->bo_start = counter->bo_end = 0;
266 }
267 
268 /**
269  * Store the SO_NUM_PRIMS_WRITTEN counters for each stream (4 uint64_t values)
270  * to prim_count_bo.
271  *
272  * If prim_count_bo is out of space, gather up the results so far into
273  * prims_generated[] and allocate a new buffer with enough space.
274  *
275  * The number of primitives written is used to compute the number of vertices
276  * written to a transform feedback stream, which is required to implement
277  * DrawTransformFeedback().
278  */
279 void
brw_save_primitives_written_counters(struct brw_context * brw,struct brw_transform_feedback_object * obj)280 brw_save_primitives_written_counters(struct brw_context *brw,
281                                      struct brw_transform_feedback_object *obj)
282 {
283    const struct gen_device_info *devinfo = &brw->screen->devinfo;
284    const struct gl_context *ctx = &brw->ctx;
285    const int streams = ctx->Const.MaxVertexStreams;
286 
287    assert(obj->prim_count_bo != NULL);
288 
289    /* Check if there's enough space for a new pair of four values. */
290    if ((obj->counter.bo_end + 2) * streams * sizeof(uint64_t) >=
291        obj->prim_count_bo->size) {
292       aggregate_transform_feedback_counter(brw, obj->prim_count_bo,
293                                            &obj->previous_counter);
294       aggregate_transform_feedback_counter(brw, obj->prim_count_bo,
295                                            &obj->counter);
296    }
297 
298    /* Flush any drawing so that the counters have the right values. */
299    brw_emit_mi_flush(brw);
300 
301    /* Emit MI_STORE_REGISTER_MEM commands to write the values. */
302    if (devinfo->gen >= 7) {
303       for (int i = 0; i < streams; i++) {
304          int offset = (streams * obj->counter.bo_end + i) * sizeof(uint64_t);
305          brw_store_register_mem64(brw, obj->prim_count_bo,
306                                   GEN7_SO_NUM_PRIMS_WRITTEN(i),
307                                   offset);
308       }
309    } else {
310       brw_store_register_mem64(brw, obj->prim_count_bo,
311                                GEN6_SO_NUM_PRIMS_WRITTEN,
312                                obj->counter.bo_end * sizeof(uint64_t));
313    }
314 
315    /* Update where to write data to. */
316    obj->counter.bo_end++;
317 }
318 
319 static void
compute_vertices_written_so_far(struct brw_context * brw,struct brw_transform_feedback_object * obj,struct brw_transform_feedback_counter * counter,uint64_t * vertices_written)320 compute_vertices_written_so_far(struct brw_context *brw,
321                                 struct brw_transform_feedback_object *obj,
322                                 struct brw_transform_feedback_counter *counter,
323                                 uint64_t *vertices_written)
324 {
325    const struct gl_context *ctx = &brw->ctx;
326    unsigned vertices_per_prim = 0;
327 
328    switch (obj->primitive_mode) {
329    case GL_POINTS:
330       vertices_per_prim = 1;
331       break;
332    case GL_LINES:
333       vertices_per_prim = 2;
334       break;
335    case GL_TRIANGLES:
336       vertices_per_prim = 3;
337       break;
338    default:
339       unreachable("Invalid transform feedback primitive mode.");
340    }
341 
342    /* Get the number of primitives generated. */
343    aggregate_transform_feedback_counter(brw, obj->prim_count_bo, counter);
344 
345    for (int i = 0; i < ctx->Const.MaxVertexStreams; i++) {
346       vertices_written[i] = vertices_per_prim * counter->accum[i];
347    }
348 }
349 
350 /**
351  * Compute the number of vertices written by the last transform feedback
352  * begin/end block.
353  */
354 static void
compute_xfb_vertices_written(struct brw_context * brw,struct brw_transform_feedback_object * obj)355 compute_xfb_vertices_written(struct brw_context *brw,
356                              struct brw_transform_feedback_object *obj)
357 {
358    if (obj->vertices_written_valid || !obj->base.EndedAnytime)
359       return;
360 
361    compute_vertices_written_so_far(brw, obj, &obj->previous_counter,
362                                    obj->vertices_written);
363    obj->vertices_written_valid = true;
364 }
365 
366 /**
367  * GetTransformFeedbackVertexCount() driver hook.
368  *
369  * Returns the number of vertices written to a particular stream by the last
370  * Begin/EndTransformFeedback block.  Used to implement DrawTransformFeedback().
371  */
372 GLsizei
brw_get_transform_feedback_vertex_count(struct gl_context * ctx,struct gl_transform_feedback_object * obj,GLuint stream)373 brw_get_transform_feedback_vertex_count(struct gl_context *ctx,
374                                         struct gl_transform_feedback_object *obj,
375                                         GLuint stream)
376 {
377    struct brw_context *brw = brw_context(ctx);
378    struct brw_transform_feedback_object *brw_obj =
379       (struct brw_transform_feedback_object *) obj;
380 
381    assert(obj->EndedAnytime);
382    assert(stream < ctx->Const.MaxVertexStreams);
383 
384    compute_xfb_vertices_written(brw, brw_obj);
385    return brw_obj->vertices_written[stream];
386 }
387 
388 void
brw_begin_transform_feedback(struct gl_context * ctx,GLenum mode,struct gl_transform_feedback_object * obj)389 brw_begin_transform_feedback(struct gl_context *ctx, GLenum mode,
390 			     struct gl_transform_feedback_object *obj)
391 {
392    struct brw_context *brw = brw_context(ctx);
393    const struct gl_program *prog;
394    const struct gl_transform_feedback_info *linked_xfb_info;
395    struct gl_transform_feedback_object *xfb_obj =
396       ctx->TransformFeedback.CurrentObject;
397    struct brw_transform_feedback_object *brw_obj =
398       (struct brw_transform_feedback_object *) xfb_obj;
399 
400    assert(brw->screen->devinfo.gen == 6);
401 
402    if (ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY]) {
403       /* BRW_NEW_GEOMETRY_PROGRAM */
404       prog = ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY];
405    } else {
406       /* BRW_NEW_VERTEX_PROGRAM */
407       prog = ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX];
408    }
409    linked_xfb_info = prog->sh.LinkedTransformFeedback;
410 
411    /* Compute the maximum number of vertices that we can write without
412     * overflowing any of the buffers currently being used for feedback.
413     */
414    brw_obj->max_index
415       = _mesa_compute_max_transform_feedback_vertices(ctx, xfb_obj,
416                                                       linked_xfb_info);
417 
418    /* Initialize the SVBI 0 register to zero and set the maximum index. */
419    BEGIN_BATCH(4);
420    OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
421    OUT_BATCH(0); /* SVBI 0 */
422    OUT_BATCH(0); /* starting index */
423    OUT_BATCH(brw_obj->max_index);
424    ADVANCE_BATCH();
425 
426    /* Initialize the rest of the unused streams to sane values.  Otherwise,
427     * they may indicate that there is no room to write data and prevent
428     * anything from happening at all.
429     */
430    for (int i = 1; i < 4; i++) {
431       BEGIN_BATCH(4);
432       OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
433       OUT_BATCH(i << SVB_INDEX_SHIFT);
434       OUT_BATCH(0); /* starting index */
435       OUT_BATCH(0xffffffff);
436       ADVANCE_BATCH();
437    }
438 
439    /* Store the starting value of the SO_NUM_PRIMS_WRITTEN counters. */
440    brw_save_primitives_written_counters(brw, brw_obj);
441 
442    brw_obj->primitive_mode = mode;
443 }
444 
445 void
brw_end_transform_feedback(struct gl_context * ctx,struct gl_transform_feedback_object * obj)446 brw_end_transform_feedback(struct gl_context *ctx,
447                            struct gl_transform_feedback_object *obj)
448 {
449    struct brw_context *brw = brw_context(ctx);
450    struct brw_transform_feedback_object *brw_obj =
451       (struct brw_transform_feedback_object *) obj;
452 
453    /* Store the ending value of the SO_NUM_PRIMS_WRITTEN counters. */
454    if (!obj->Paused)
455       brw_save_primitives_written_counters(brw, brw_obj);
456 
457    /* We've reached the end of a transform feedback begin/end block.  This
458     * means that future DrawTransformFeedback() calls will need to pick up the
459     * results of the current counter, and that it's time to roll back the
460     * current primitive counter to zero.
461     */
462    brw_obj->previous_counter = brw_obj->counter;
463    brw_reset_transform_feedback_counter(&brw_obj->counter);
464 
465    /* EndTransformFeedback() means that we need to update the number of
466     * vertices written.  Since it's only necessary if DrawTransformFeedback()
467     * is called and it means mapping a buffer object, we delay computing it
468     * until it's absolutely necessary to try and avoid stalls.
469     */
470    brw_obj->vertices_written_valid = false;
471 }
472 
473 void
brw_pause_transform_feedback(struct gl_context * ctx,struct gl_transform_feedback_object * obj)474 brw_pause_transform_feedback(struct gl_context *ctx,
475                              struct gl_transform_feedback_object *obj)
476 {
477    struct brw_context *brw = brw_context(ctx);
478    struct brw_transform_feedback_object *brw_obj =
479       (struct brw_transform_feedback_object *) obj;
480 
481    /* Store the temporary ending value of the SO_NUM_PRIMS_WRITTEN counters.
482     * While this operation is paused, other transform feedback actions may
483     * occur, which will contribute to the counters.  We need to exclude that
484     * from our counts.
485     */
486    brw_save_primitives_written_counters(brw, brw_obj);
487 }
488 
489 void
brw_resume_transform_feedback(struct gl_context * ctx,struct gl_transform_feedback_object * obj)490 brw_resume_transform_feedback(struct gl_context *ctx,
491                               struct gl_transform_feedback_object *obj)
492 {
493    struct brw_context *brw = brw_context(ctx);
494    struct brw_transform_feedback_object *brw_obj =
495       (struct brw_transform_feedback_object *) obj;
496 
497    /* Reload SVBI 0 with the count of vertices written so far. */
498    uint64_t svbi;
499    compute_vertices_written_so_far(brw, brw_obj, &brw_obj->counter, &svbi);
500 
501    BEGIN_BATCH(4);
502    OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
503    OUT_BATCH(0); /* SVBI 0 */
504    OUT_BATCH((uint32_t) svbi); /* starting index */
505    OUT_BATCH(brw_obj->max_index);
506    ADVANCE_BATCH();
507 
508    /* Initialize the rest of the unused streams to sane values.  Otherwise,
509     * they may indicate that there is no room to write data and prevent
510     * anything from happening at all.
511     */
512    for (int i = 1; i < 4; i++) {
513       BEGIN_BATCH(4);
514       OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
515       OUT_BATCH(i << SVB_INDEX_SHIFT);
516       OUT_BATCH(0); /* starting index */
517       OUT_BATCH(0xffffffff);
518       ADVANCE_BATCH();
519    }
520 
521    /* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
522    brw_save_primitives_written_counters(brw, brw_obj);
523 }
524