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