src/panfrost/bifrost/bi_pack.c

   1 /*
   2  * Copyright (C) 2020 Collabora, Ltd.
   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 FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  */
  23
  24 #include "compiler.h"
  25
  26 #define RETURN_PACKED(str) { \
  27         uint64_t temp = 0; \
  28         memcpy(&temp, &str, sizeof(str)); \
  29         return temp; \
  30 }
  31
  32 /* This file contains the final passes of the compiler. Running after
  33  * scheduling and RA, the IR is now finalized, so we need to emit it to actual
  34  * bits on the wire (as well as fixup branches) */
  35
  36 static uint64_t
  37 bi_pack_header(bi_clause *clause, bi_clause *next)
  38 {
  39         struct bifrost_header header = {
  40                 /* stub */
  41                 .no_end_of_shader = (next != NULL),
  42         };
  43
  44         uint64_t u = 0;
  45         memcpy(&u, &header, sizeof(header));
  46         return u;
  47 }
  48
  49 /* Represents the assignment of ports for a given bundle */
  50
  51 struct bi_registers {
  52         /* Register to assign to each port */
  53         unsigned port[4];
  54
  55         /* Read ports can be disabled */
  56         bool enabled[2];
  57
  58         /* Should we write FMA? what about ADD? If only a single port is
  59          * enabled it is in port 2, else ADD/FMA is 2/3 respectively */
  60         bool write_fma, write_add;
  61
  62         /* Should we read with port 3? */
  63         bool read_port3;
  64
  65         /* Packed uniform/constant */
  66         unsigned uniform_constant;
  67
  68         /* Whether writes are actually for the last instruction */
  69         bool first_instruction;
  70 };
  71
  72 /* Assigns a port for reading, before anything is written */
  73
  74 static void
  75 bi_assign_port_read(struct bi_registers *regs, unsigned src)
  76 {
  77         /* We only assign for registers */
  78         if (!(src & BIR_INDEX_REGISTER))
  79                 return;
  80
  81         unsigned reg = src & ~BIR_INDEX_REGISTER;
  82
  83         /* Check if we already assigned the port */
  84         for (unsigned i = 0; i <= 1; ++i) {
  85                 if (regs->port[i] == reg && regs->enabled[i])
  86                         return;
  87         }
  88
  89         if (regs->port[3] == reg && regs->read_port3)
  90                 return;
  91
  92         /* Assign it now */
  93
  94         for (unsigned i = 0; i <= 1; ++i) {
  95                 if (!regs->enabled[i]) {
  96                         regs->port[i] = reg;
  97                         regs->enabled[i] = true;
  98                         return;
  99                 }
 100         }
 101
 102         if (!regs->read_port3) {
 103                 regs->port[3] = reg;
 104                 regs->read_port3 = true;
 105         }
 106 }
 107
 108 static struct bi_registers
 109 bi_assign_ports(bi_bundle now, bi_bundle prev)
 110 {
 111         struct bi_registers regs = { 0 };
 112
 113         /* We assign ports for the main register mechanism. Special ops
 114          * use the data registers, which has its own mechanism entirely
 115          * and thus gets skipped over here. */
 116
 117         unsigned read_dreg = now.add &&
 118                 bi_class_props[now.add->type] & BI_DATA_REG_SRC;
 119
 120         unsigned write_dreg = prev.add &&
 121                 bi_class_props[prev.add->type] & BI_DATA_REG_DEST;
 122
 123         /* First, assign reads */
 124
 125         if (now.fma)
 126                 bi_foreach_src(now.fma, src)
 127                         bi_assign_port_read(&regs, now.fma->src[src]);
 128
 129         if (now.add) {
 130                 bi_foreach_src(now.add, src) {
 131                         if (!(src == 0 && read_dreg))
 132                                 bi_assign_port_read(&regs, now.add->src[src]);
 133                 }
 134         }
 135
 136         /* Next, assign writes */
 137
 138         if (prev.fma && prev.fma->dest & BIR_INDEX_REGISTER) {
 139                 regs.port[2] = prev.fma->dest & ~BIR_INDEX_REGISTER;
 140                 regs.write_fma = true;
 141         }
 142
 143         if (prev.add && prev.add->dest & BIR_INDEX_REGISTER && !write_dreg) {
 144                 unsigned r = prev.add->dest & ~BIR_INDEX_REGISTER;
 145
 146                 if (regs.write_fma) {
 147                         /* Scheduler constraint: cannot read 3 and write 2 */
 148                         assert(!regs.read_port3);
 149                         regs.port[3] = r;
 150                 } else {
 151                         regs.port[2] = r;
 152                 }
 153
 154                 regs.write_add = true;
 155         }
 156
 157         /* Finally, ensure port 1 > port 0 for the 63-x trick to function */
 158
 159         if (regs.enabled[0] && regs.enabled[1] && regs.port[1] < regs.port[0]) {
 160                 unsigned temp = regs.port[0];
 161                 regs.port[0] = regs.port[1];
 162                 regs.port[1] = temp;
 163         }
 164
 165         return regs;
 166 }
 167
 168 /* Determines the register control field, ignoring the first? flag */
 169
 170 static enum bifrost_reg_control
 171 bi_pack_register_ctrl_lo(struct bi_registers r)
 172 {
 173         if (r.write_fma) {
 174                 if (r.write_add) {
 175                         assert(!r.read_port3);
 176                         return BIFROST_WRITE_ADD_P2_FMA_P3;
 177                 } else {
 178                         if (r.read_port3)
 179                                 return BIFROST_WRITE_FMA_P2_READ_P3;
 180                         else
 181                                 return BIFROST_WRITE_FMA_P2;
 182                 }
 183         } else if (r.write_add) {
 184                 if (r.read_port3)
 185                         return BIFROST_WRITE_ADD_P2_READ_P3;
 186                 else
 187                         return BIFROST_WRITE_ADD_P2;
 188         } else if (r.read_port3)
 189                 return BIFROST_READ_P3;
 190         else
 191                 return BIFROST_REG_NONE;
 192 }
 193
 194 /* Ditto but account for the first? flag this time */
 195
 196 static enum bifrost_reg_control
 197 bi_pack_register_ctrl(struct bi_registers r)
 198 {
 199         enum bifrost_reg_control ctrl = bi_pack_register_ctrl_lo(r);
 200
 201         if (r.first_instruction) {
 202                 if (ctrl == BIFROST_REG_NONE)
 203                         ctrl = BIFROST_FIRST_NONE;
 204                 else
 205                         ctrl |= BIFROST_FIRST_NONE;
 206         }
 207
 208         return ctrl;
 209 }
 210
 211 static uint64_t
 212 bi_pack_registers(struct bi_registers regs)
 213 {
 214         enum bifrost_reg_control ctrl = bi_pack_register_ctrl(regs);
 215         struct bifrost_regs s;
 216         uint64_t packed = 0;
 217
 218         if (regs.enabled[1]) {
 219                 /* Gotta save that bit!~ Required by the 63-x trick */
 220                 assert(regs.port[1] > regs.port[0]);
 221                 assert(regs.enabled[0]);
 222
 223                 /* Do the 63-x trick, see docs/disasm */
 224                 if (regs.port[0] > 31) {
 225                         regs.port[0] = 63 - regs.port[0];
 226                         regs.port[1] = 63 - regs.port[1];
 227                 }
 228
 229                 assert(regs.port[0] <= 31);
 230                 assert(regs.port[1] <= 63);
 231
 232                 s.ctrl = ctrl;
 233                 s.reg1 = regs.port[1];
 234                 s.reg0 = regs.port[0];
 235         } else {
 236                 /* Port 1 disabled, so set to zero and use port 1 for ctrl */
 237                 s.reg1 = ctrl << 2;
 238
 239                 if (regs.enabled[0]) {
 240                         /* Bit 0 upper bit of port 0 */
 241                         s.reg1 |= (regs.port[0] >> 5);
 242
 243                         /* Rest of port 0 in usual spot */
 244                         s.reg0 = (regs.port[0] & 0b11111);
 245                 } else {
 246                         /* Bit 1 set if port 0 also disabled */
 247                         s.reg1 |= (1 << 1);
 248                 }
 249         }
 250
 251         s.reg3 = regs.port[3];
 252         s.reg2 = regs.port[2];
 253         s.uniform_const = regs.uniform_constant;
 254
 255         memcpy(&packed, &s, sizeof(s));
 256         return packed;
 257 }
 258
 259 static enum bifrost_packed_src
 260 bi_get_src_reg_port(struct bi_registers *regs, unsigned src)
 261 {
 262         unsigned reg = src & ~BIR_INDEX_REGISTER;
 263
 264         if (regs->port[0] == reg && regs->enabled[0])
 265                 return BIFROST_SRC_PORT0;
 266         else if (regs->port[1] == reg && regs->enabled[1])
 267                 return BIFROST_SRC_PORT1;
 268         else if (regs->port[3] == reg && regs->read_port3)
 269                 return BIFROST_SRC_PORT3;
 270         else
 271                 unreachable("Tried to access register with no port");
 272 }
 273
 274 static enum bifrost_packed_src
 275 bi_get_src_const(struct bi_registers *regs, unsigned constant)
 276 {
 277         if (regs->uniform_constant & (1 << 7))
 278                 unreachable("Tried to get constant but loading uniforms");
 279
 280         unsigned loc = (regs->uniform_constant >> 4) & 0x7;
 281
 282         if (loc != 0)
 283                 unreachable("TODO: constants in clauses");
 284
 285         unsigned lo = regs->uniform_constant & 0xF;
 286
 287         if (lo == 0) {
 288                 if (constant != 0)
 289                         unreachable("Tried to load !0 in 0 slot");
 290
 291                 return BIFROST_SRC_CONST_LO;
 292         } else {
 293                 unreachable("Special slot is not a fixed immediate");
 294         }
 295 }
 296
 297 static enum bifrost_packed_src
 298 bi_get_src(bi_instruction *ins, struct bi_registers *regs, unsigned s, bool is_fma)
 299 {
 300         unsigned src = ins->src[s];
 301
 302         if (src & BIR_INDEX_REGISTER)
 303                 return bi_get_src_reg_port(regs, src);
 304         else if (src & BIR_INDEX_ZERO && is_fma)
 305                 return BIFROST_SRC_STAGE;
 306         else if (src & BIR_INDEX_ZERO)
 307                 return bi_get_src_const(regs, 0);
 308         else if (src & BIR_INDEX_PASS)
 309                 return src & ~BIR_INDEX_PASS;
 310         else
 311                 unreachable("Unknown src");
 312 }
 313
 314 static unsigned
 315 bi_pack_fma_fma(bi_instruction *ins, struct bi_registers *regs)
 316 {
 317         /* (-a)(-b) = ab, so we only need one negate bit */
 318         bool negate_mul = ins->src_neg[0] ^ ins->src_neg[1];
 319
 320         struct bifrost_fma_fma pack = {
 321                 .src0 = bi_get_src(ins, regs, 0, true),
 322                 .src1 = bi_get_src(ins, regs, 1, true),
 323                 .src2 = bi_get_src(ins, regs, 2, true),
 324                 .src0_abs = ins->src_abs[0],
 325                 .src1_abs = ins->src_abs[1],
 326                 .src2_abs = ins->src_abs[2],
 327                 .src0_neg = negate_mul,
 328                 .src2_neg = ins->src_neg[2],
 329                 .op = BIFROST_FMA_OP_FMA
 330         };
 331
 332         RETURN_PACKED(pack);
 333 }
 334
 335 static unsigned
 336 bi_pack_fma_add(bi_instruction *ins, struct bi_registers *regs)
 337 {
 338         /* TODO: fadd16 packing is a bit different */
 339         assert(ins->dest_type == nir_type_float32);
 340
 341         struct bifrost_fma_add pack = {
 342                 .src0 = bi_get_src(ins, regs, 0, true),
 343                 .src1 = bi_get_src(ins, regs, 1, true),
 344                 .src0_abs = ins->src_abs[0],
 345                 .src1_abs = ins->src_abs[1],
 346                 .src0_neg = ins->src_neg[0],
 347                 .src1_neg = ins->src_neg[1],
 348                 .unk = 0x0,
 349                 .outmod = ins->outmod,
 350                 .roundmode = ins->roundmode,
 351                 .op = BIFROST_FMA_OP_FADD32
 352         };
 353
 354         RETURN_PACKED(pack);
 355 }
 356
 357 static unsigned
 358 bi_pack_fma(bi_clause *clause, bi_bundle bundle, struct bi_registers *regs)
 359 {
 360         if (!bundle.fma)
 361                 return BIFROST_FMA_NOP;
 362
 363         switch (bundle.fma->type) {
 364         case BI_ADD:
 365                 return bi_pack_fma_add(bundle.fma, regs);
 366         case BI_CMP:
 367         case BI_BITWISE:
 368         case BI_CONVERT:
 369         case BI_CSEL:
 370                 return BIFROST_FMA_NOP;
 371         case BI_FMA:
 372                 return bi_pack_fma_fma(bundle.fma, regs);
 373         case BI_FREXP:
 374         case BI_ISUB:
 375         case BI_MINMAX:
 376         case BI_MOV:
 377         case BI_SHIFT:
 378         case BI_SWIZZLE:
 379         case BI_ROUND:
 380                 return BIFROST_FMA_NOP;
 381         default:
 382                 unreachable("Cannot encode class as FMA");
 383         }
 384 }
 385
 386 static unsigned
 387 bi_pack_add_ld_vary(bi_instruction *ins, struct bi_registers *regs)
 388 {
 389         unsigned size = nir_alu_type_get_type_size(ins->dest_type);
 390         assert(size == 32 || size == 16);
 391
 392         unsigned op = (size == 32) ?
 393                 BIFROST_ADD_OP_LD_VAR_32 :
 394                 BIFROST_ADD_OP_LD_VAR_16;
 395
 396         unsigned cmask = bi_from_bytemask(ins->writemask, size / 8);
 397         unsigned channels = util_bitcount(cmask);
 398         assert(cmask == ((1 << channels) - 1));
 399
 400         unsigned packed_addr = 0;
 401
 402         if (ins->src[0] & BIR_INDEX_CONSTANT) {
 403                 /* Direct uses address field directly */
 404                 packed_addr = ins->src[0] & ~BIR_INDEX_CONSTANT;
 405                 assert(packed_addr < 0b1000);
 406         } else {
 407                 /* Indirect gets an extra source */
 408                 packed_addr = bi_get_src(ins, regs, 0, false) | 0b11000;
 409         }
 410
 411         assert(channels >= 1 && channels <= 4);
 412
 413         struct bifrost_ld_var pack = {
 414                 .src0 = bi_get_src(ins, regs, 1, false),
 415                 .addr = packed_addr,
 416                 .channels = MALI_POSITIVE(channels),
 417                 .interp_mode = ins->load_vary.interp_mode,
 418                 .reuse = ins->load_vary.reuse,
 419                 .flat = ins->load_vary.flat,
 420                 .op = op
 421         };
 422
 423         RETURN_PACKED(pack);
 424 }
 425
 426 static unsigned
 427 bi_pack_add(bi_clause *clause, bi_bundle bundle, struct bi_registers *regs)
 428 {
 429         if (!bundle.add)
 430                 return BIFROST_ADD_NOP;
 431
 432         switch (bundle.add->type) {
 433         case BI_ADD:
 434         case BI_ATEST:
 435         case BI_BRANCH:
 436         case BI_CMP:
 437         case BI_BLEND:
 438         case BI_BITWISE:
 439         case BI_CONVERT:
 440         case BI_DISCARD:
 441         case BI_FREXP:
 442         case BI_ISUB:
 443         case BI_LOAD:
 444         case BI_LOAD_UNIFORM:
 445         case BI_LOAD_ATTR:
 446                 return BIFROST_ADD_NOP;
 447         case BI_LOAD_VAR:
 448                 return bi_pack_add_ld_vary(bundle.add, regs);
 449         case BI_LOAD_VAR_ADDRESS:
 450         case BI_MINMAX:
 451         case BI_MOV:
 452         case BI_SHIFT:
 453         case BI_STORE:
 454         case BI_STORE_VAR:
 455         case BI_SPECIAL:
 456         case BI_SWIZZLE:
 457         case BI_TEX:
 458         case BI_ROUND:
 459                 return BIFROST_ADD_NOP;
 460         default:
 461                 unreachable("Cannot encode class as ADD");
 462         }
 463 }
 464
 465 struct bi_packed_bundle {
 466         uint64_t lo;
 467         uint64_t hi;
 468 };
 469
 470 static struct bi_packed_bundle
 471 bi_pack_bundle(bi_clause *clause, bi_bundle bundle, bi_bundle prev, bool first_bundle)
 472 {
 473         struct bi_registers regs = bi_assign_ports(bundle, prev);
 474         regs.first_instruction = first_bundle;
 475
 476         uint64_t reg = bi_pack_registers(regs);
 477         uint64_t fma = bi_pack_fma(clause, bundle, &regs);
 478         uint64_t add = bi_pack_add(clause, bundle, &regs);
 479
 480         struct bi_packed_bundle packed = {
 481                 .lo = reg | (fma << 35) | ((add & 0b111111) << 58),
 482                 .hi = add >> 6
 483         };
 484
 485         return packed;
 486 }
 487
 488 static void
 489 bi_pack_clause(bi_context *ctx, bi_clause *clause, bi_clause *next,
 490                 struct util_dynarray *emission)
 491 {
 492         struct bi_packed_bundle ins_1 = bi_pack_bundle(clause, clause->bundles[0], clause->bundles[0], true);
 493         assert(clause->bundle_count == 1);
 494
 495         struct bifrost_fmt1 quad_1 = {
 496                 .tag = BIFROST_FMT1_FINAL,
 497                 .header = bi_pack_header(clause, next),
 498                 .ins_1 = ins_1.lo,
 499                 .ins_2 = ins_1.hi & ((1 << 11) - 1),
 500                 .ins_0 = (ins_1.hi >> 11) & 0b111,
 501         };
 502
 503         util_dynarray_append(emission, struct bifrost_fmt1, quad_1);
 504 }
 505
 506 static bi_clause *
 507 bi_next_clause(bi_context *ctx, pan_block *block, bi_clause *clause)
 508 {
 509         /* Try the next clause in this block */
 510         if (clause->link.next != &((bi_block *) block)->clauses)
 511                 return list_first_entry(&(clause->link), bi_clause, link);
 512
 513         /* Try the next block, or the one after that if it's empty, etc .*/
 514         pan_block *next_block = pan_next_block(block);
 515
 516         bi_foreach_block_from(ctx, next_block, block) {
 517                 bi_block *blk = (bi_block *) block;
 518
 519                 if (!list_is_empty(&blk->clauses))
 520                         return list_first_entry(&(blk->clauses), bi_clause, link);
 521         }
 522
 523         return NULL;
 524 }
 525
 526 void
 527 bi_pack(bi_context *ctx, struct util_dynarray *emission)
 528 {
 529         util_dynarray_init(emission, NULL);
 530
 531         bi_foreach_block(ctx, _block) {
 532                 bi_block *block = (bi_block *) _block;
 533
 534                 bi_foreach_clause_in_block(block, clause) {
 535                         bi_clause *next = bi_next_clause(ctx, _block, clause);
 536                         bi_pack_clause(ctx, clause, next, emission);
 537                 }
 538         }
 539 }