hw/misc/mips_itu.c

   1 /*
   2  * Inter-Thread Communication Unit emulation.
   3  *
   4  * Copyright (c) 2016 Imagination Technologies
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "qemu/units.h"
  22 #include "qemu/log.h"
  23 #include "qemu/module.h"
  24 #include "qapi/error.h"
  25 #include "exec/exec-all.h"
  26 #include "hw/misc/mips_itu.h"
  27 #include "hw/qdev-properties.h"
  28
  29 #define ITC_TAG_ADDRSPACE_SZ (ITC_ADDRESSMAP_NUM * 8)
  30 /* Initialize as 4kB area to fit all 32 cells with default 128B grain.
  31    Storage may be resized by the software. */
  32 #define ITC_STORAGE_ADDRSPACE_SZ 0x1000
  33
  34 #define ITC_FIFO_NUM_MAX 16
  35 #define ITC_SEMAPH_NUM_MAX 16
  36 #define ITC_AM1_NUMENTRIES_OFS 20
  37
  38 #define ITC_CELL_PV_MAX_VAL 0xFFFF
  39
  40 #define ITC_CELL_TAG_FIFO_DEPTH 28
  41 #define ITC_CELL_TAG_FIFO_PTR 18
  42 #define ITC_CELL_TAG_FIFO 17
  43 #define ITC_CELL_TAG_T 16
  44 #define ITC_CELL_TAG_F 1
  45 #define ITC_CELL_TAG_E 0
  46
  47 #define ITC_AM0_BASE_ADDRESS_MASK 0xFFFFFC00ULL
  48 #define ITC_AM0_EN_MASK 0x1
  49
  50 #define ITC_AM1_ADDR_MASK_MASK 0x1FC00
  51 #define ITC_AM1_ENTRY_GRAIN_MASK 0x7
  52
  53 typedef enum ITCView {
  54     ITCVIEW_BYPASS  = 0,
  55     ITCVIEW_CONTROL = 1,
  56     ITCVIEW_EF_SYNC = 2,
  57     ITCVIEW_EF_TRY  = 3,
  58     ITCVIEW_PV_SYNC = 4,
  59     ITCVIEW_PV_TRY  = 5,
  60     ITCVIEW_PV_ICR0 = 15,
  61 } ITCView;
  62
  63 #define ITC_ICR0_CELL_NUM        16
  64 #define ITC_ICR0_BLK_GRAIN       8
  65 #define ITC_ICR0_BLK_GRAIN_MASK  0x7
  66 #define ITC_ICR0_ERR_AXI         2
  67 #define ITC_ICR0_ERR_PARITY      1
  68 #define ITC_ICR0_ERR_EXEC        0
  69
  70 MemoryRegion *mips_itu_get_tag_region(MIPSITUState *itu)
  71 {
  72     return &itu->tag_io;
  73 }
  74
  75 static uint64_t itc_tag_read(void *opaque, hwaddr addr, unsigned size)
  76 {
  77     MIPSITUState *tag = (MIPSITUState *)opaque;
  78     uint64_t index = addr >> 3;
  79
  80     if (index >= ITC_ADDRESSMAP_NUM) {
  81         qemu_log_mask(LOG_GUEST_ERROR, "Read 0x%" PRIx64 "\n", addr);
  82         return 0;
  83     }
  84
  85     return tag->ITCAddressMap[index];
  86 }
  87
  88 void itc_reconfigure(MIPSITUState *tag)
  89 {
  90     uint64_t *am = &tag->ITCAddressMap[0];
  91     MemoryRegion *mr = &tag->storage_io;
  92     hwaddr address = am[0] & ITC_AM0_BASE_ADDRESS_MASK;
  93     uint64_t size = (1 * KiB) + (am[1] & ITC_AM1_ADDR_MASK_MASK);
  94     bool is_enabled = (am[0] & ITC_AM0_EN_MASK) != 0;
  95
  96     if (tag->saar_present) {
  97         address = ((*(uint64_t *) tag->saar) & 0xFFFFFFFFE000ULL) << 4;
  98         size = 1ULL << ((*(uint64_t *) tag->saar >> 1) & 0x1f);
  99         is_enabled = *(uint64_t *) tag->saar & 1;
 100     }
 101
 102     memory_region_transaction_begin();
 103     if (!(size & (size - 1))) {
 104         memory_region_set_size(mr, size);
 105     }
 106     memory_region_set_address(mr, address);
 107     memory_region_set_enabled(mr, is_enabled);
 108     memory_region_transaction_commit();
 109 }
 110
 111 static void itc_tag_write(void *opaque, hwaddr addr,
 112                           uint64_t data, unsigned size)
 113 {
 114     MIPSITUState *tag = (MIPSITUState *)opaque;
 115     uint64_t *am = &tag->ITCAddressMap[0];
 116     uint64_t am_old, mask;
 117     uint64_t index = addr >> 3;
 118
 119     switch (index) {
 120     case 0:
 121         mask = ITC_AM0_BASE_ADDRESS_MASK | ITC_AM0_EN_MASK;
 122         break;
 123     case 1:
 124         mask = ITC_AM1_ADDR_MASK_MASK | ITC_AM1_ENTRY_GRAIN_MASK;
 125         break;
 126     default:
 127         qemu_log_mask(LOG_GUEST_ERROR, "Bad write 0x%" PRIx64 "\n", addr);
 128         return;
 129     }
 130
 131     am_old = am[index];
 132     am[index] = (data & mask) | (am_old & ~mask);
 133     if (am_old != am[index]) {
 134         itc_reconfigure(tag);
 135     }
 136 }
 137
 138 static const MemoryRegionOps itc_tag_ops = {
 139     .read = itc_tag_read,
 140     .write = itc_tag_write,
 141     .impl = {
 142         .max_access_size = 8,
 143     },
 144     .endianness = DEVICE_NATIVE_ENDIAN,
 145 };
 146
 147 static inline uint32_t get_num_cells(MIPSITUState *s)
 148 {
 149     return s->num_fifo + s->num_semaphores;
 150 }
 151
 152 static inline ITCView get_itc_view(hwaddr addr)
 153 {
 154     return (addr >> 3) & 0xf;
 155 }
 156
 157 static inline int get_cell_stride_shift(const MIPSITUState *s)
 158 {
 159     /* Minimum interval (for EntryGain = 0) is 128 B */
 160     if (s->saar_present) {
 161         return 7 + ((s->icr0 >> ITC_ICR0_BLK_GRAIN) &
 162                     ITC_ICR0_BLK_GRAIN_MASK);
 163     } else {
 164         return 7 + (s->ITCAddressMap[1] & ITC_AM1_ENTRY_GRAIN_MASK);
 165     }
 166 }
 167
 168 static inline ITCStorageCell *get_cell(MIPSITUState *s,
 169                                        hwaddr addr)
 170 {
 171     uint32_t cell_idx = addr >> get_cell_stride_shift(s);
 172     uint32_t num_cells = get_num_cells(s);
 173
 174     if (cell_idx >= num_cells) {
 175         cell_idx = num_cells - 1;
 176     }
 177
 178     return &s->cell[cell_idx];
 179 }
 180
 181 static void wake_blocked_threads(ITCStorageCell *c)
 182 {
 183     CPUState *cs;
 184     CPU_FOREACH(cs) {
 185         if (cs->halted && (c->blocked_threads & (1ULL << cs->cpu_index))) {
 186             cpu_interrupt(cs, CPU_INTERRUPT_WAKE);
 187         }
 188     }
 189     c->blocked_threads = 0;
 190 }
 191
 192 static void QEMU_NORETURN block_thread_and_exit(ITCStorageCell *c)
 193 {
 194     c->blocked_threads |= 1ULL << current_cpu->cpu_index;
 195     current_cpu->halted = 1;
 196     current_cpu->exception_index = EXCP_HLT;
 197     cpu_loop_exit_restore(current_cpu, current_cpu->mem_io_pc);
 198 }
 199
 200 /* ITC Bypass View */
 201
 202 static inline uint64_t view_bypass_read(ITCStorageCell *c)
 203 {
 204     if (c->tag.FIFO) {
 205         return c->data[c->fifo_out];
 206     } else {
 207         return c->data[0];
 208     }
 209 }
 210
 211 static inline void view_bypass_write(ITCStorageCell *c, uint64_t val)
 212 {
 213     if (c->tag.FIFO && (c->tag.FIFOPtr > 0)) {
 214         int idx = (c->fifo_out + c->tag.FIFOPtr - 1) % ITC_CELL_DEPTH;
 215         c->data[idx] = val;
 216     }
 217
 218     /* ignore a write to the semaphore cell */
 219 }
 220
 221 /* ITC Control View */
 222
 223 static inline uint64_t view_control_read(ITCStorageCell *c)
 224 {
 225     return ((uint64_t)c->tag.FIFODepth << ITC_CELL_TAG_FIFO_DEPTH) |
 226            (c->tag.FIFOPtr << ITC_CELL_TAG_FIFO_PTR) |
 227            (c->tag.FIFO << ITC_CELL_TAG_FIFO) |
 228            (c->tag.T << ITC_CELL_TAG_T) |
 229            (c->tag.E << ITC_CELL_TAG_E) |
 230            (c->tag.F << ITC_CELL_TAG_F);
 231 }
 232
 233 static inline void view_control_write(ITCStorageCell *c, uint64_t val)
 234 {
 235     c->tag.T = (val >> ITC_CELL_TAG_T) & 1;
 236     c->tag.E = (val >> ITC_CELL_TAG_E) & 1;
 237     c->tag.F = (val >> ITC_CELL_TAG_F) & 1;
 238
 239     if (c->tag.E) {
 240         c->tag.FIFOPtr = 0;
 241     }
 242 }
 243
 244 /* ITC Empty/Full View */
 245
 246 static uint64_t view_ef_common_read(ITCStorageCell *c, bool blocking)
 247 {
 248     uint64_t ret = 0;
 249
 250     if (!c->tag.FIFO) {
 251         return 0;
 252     }
 253
 254     c->tag.F = 0;
 255
 256     if (blocking && c->tag.E) {
 257         block_thread_and_exit(c);
 258     }
 259
 260     if (c->blocked_threads) {
 261         wake_blocked_threads(c);
 262     }
 263
 264     if (c->tag.FIFOPtr > 0) {
 265         ret = c->data[c->fifo_out];
 266         c->fifo_out = (c->fifo_out + 1) % ITC_CELL_DEPTH;
 267         c->tag.FIFOPtr--;
 268     }
 269
 270     if (c->tag.FIFOPtr == 0) {
 271         c->tag.E = 1;
 272     }
 273
 274     return ret;
 275 }
 276
 277 static uint64_t view_ef_sync_read(ITCStorageCell *c)
 278 {
 279     return view_ef_common_read(c, true);
 280 }
 281
 282 static uint64_t view_ef_try_read(ITCStorageCell *c)
 283 {
 284     return view_ef_common_read(c, false);
 285 }
 286
 287 static inline void view_ef_common_write(ITCStorageCell *c, uint64_t val,
 288                                         bool blocking)
 289 {
 290     if (!c->tag.FIFO) {
 291         return;
 292     }
 293
 294     c->tag.E = 0;
 295
 296     if (blocking && c->tag.F) {
 297         block_thread_and_exit(c);
 298     }
 299
 300     if (c->blocked_threads) {
 301         wake_blocked_threads(c);
 302     }
 303
 304     if (c->tag.FIFOPtr < ITC_CELL_DEPTH) {
 305         int idx = (c->fifo_out + c->tag.FIFOPtr) % ITC_CELL_DEPTH;
 306         c->data[idx] = val;
 307         c->tag.FIFOPtr++;
 308     }
 309
 310     if (c->tag.FIFOPtr == ITC_CELL_DEPTH) {
 311         c->tag.F = 1;
 312     }
 313 }
 314
 315 static void view_ef_sync_write(ITCStorageCell *c, uint64_t val)
 316 {
 317     view_ef_common_write(c, val, true);
 318 }
 319
 320 static void view_ef_try_write(ITCStorageCell *c, uint64_t val)
 321 {
 322     view_ef_common_write(c, val, false);
 323 }
 324
 325 /* ITC P/V View */
 326
 327 static uint64_t view_pv_common_read(ITCStorageCell *c, bool blocking)
 328 {
 329     uint64_t ret = c->data[0];
 330
 331     if (c->tag.FIFO) {
 332         return 0;
 333     }
 334
 335     if (c->data[0] > 0) {
 336         c->data[0]--;
 337     } else if (blocking) {
 338         block_thread_and_exit(c);
 339     }
 340
 341     return ret;
 342 }
 343
 344 static uint64_t view_pv_sync_read(ITCStorageCell *c)
 345 {
 346     return view_pv_common_read(c, true);
 347 }
 348
 349 static uint64_t view_pv_try_read(ITCStorageCell *c)
 350 {
 351     return view_pv_common_read(c, false);
 352 }
 353
 354 static inline void view_pv_common_write(ITCStorageCell *c)
 355 {
 356     if (c->tag.FIFO) {
 357         return;
 358     }
 359
 360     if (c->data[0] < ITC_CELL_PV_MAX_VAL) {
 361         c->data[0]++;
 362     }
 363
 364     if (c->blocked_threads) {
 365         wake_blocked_threads(c);
 366     }
 367 }
 368
 369 static void view_pv_sync_write(ITCStorageCell *c)
 370 {
 371     view_pv_common_write(c);
 372 }
 373
 374 static void view_pv_try_write(ITCStorageCell *c)
 375 {
 376     view_pv_common_write(c);
 377 }
 378
 379 static void raise_exception(int excp)
 380 {
 381     current_cpu->exception_index = excp;
 382     cpu_loop_exit(current_cpu);
 383 }
 384
 385 static uint64_t itc_storage_read(void *opaque, hwaddr addr, unsigned size)
 386 {
 387     MIPSITUState *s = (MIPSITUState *)opaque;
 388     ITCStorageCell *cell = get_cell(s, addr);
 389     ITCView view = get_itc_view(addr);
 390     uint64_t ret = -1;
 391
 392     switch (size) {
 393     case 1:
 394     case 2:
 395         s->icr0 |= 1 << ITC_ICR0_ERR_AXI;
 396         raise_exception(EXCP_DBE);
 397         return 0;
 398     }
 399
 400     switch (view) {
 401     case ITCVIEW_BYPASS:
 402         ret = view_bypass_read(cell);
 403         break;
 404     case ITCVIEW_CONTROL:
 405         ret = view_control_read(cell);
 406         break;
 407     case ITCVIEW_EF_SYNC:
 408         ret = view_ef_sync_read(cell);
 409         break;
 410     case ITCVIEW_EF_TRY:
 411         ret = view_ef_try_read(cell);
 412         break;
 413     case ITCVIEW_PV_SYNC:
 414         ret = view_pv_sync_read(cell);
 415         break;
 416     case ITCVIEW_PV_TRY:
 417         ret = view_pv_try_read(cell);
 418         break;
 419     case ITCVIEW_PV_ICR0:
 420         ret = s->icr0;
 421         break;
 422     default:
 423         qemu_log_mask(LOG_GUEST_ERROR,
 424                       "itc_storage_read: Bad ITC View %d\n", (int)view);
 425         break;
 426     }
 427
 428     return ret;
 429 }
 430
 431 static void itc_storage_write(void *opaque, hwaddr addr, uint64_t data,
 432                               unsigned size)
 433 {
 434     MIPSITUState *s = (MIPSITUState *)opaque;
 435     ITCStorageCell *cell = get_cell(s, addr);
 436     ITCView view = get_itc_view(addr);
 437
 438     switch (size) {
 439     case 1:
 440     case 2:
 441         s->icr0 |= 1 << ITC_ICR0_ERR_AXI;
 442         raise_exception(EXCP_DBE);
 443         return;
 444     }
 445
 446     switch (view) {
 447     case ITCVIEW_BYPASS:
 448         view_bypass_write(cell, data);
 449         break;
 450     case ITCVIEW_CONTROL:
 451         view_control_write(cell, data);
 452         break;
 453     case ITCVIEW_EF_SYNC:
 454         view_ef_sync_write(cell, data);
 455         break;
 456     case ITCVIEW_EF_TRY:
 457         view_ef_try_write(cell, data);
 458         break;
 459     case ITCVIEW_PV_SYNC:
 460         view_pv_sync_write(cell);
 461         break;
 462     case ITCVIEW_PV_TRY:
 463         view_pv_try_write(cell);
 464         break;
 465     case ITCVIEW_PV_ICR0:
 466         if (data & 0x7) {
 467             /* clear ERROR bits */
 468             s->icr0 &= ~(data & 0x7);
 469         }
 470         /* set BLK_GRAIN */
 471         s->icr0 &= ~0x700;
 472         s->icr0 |= data & 0x700;
 473         break;
 474     default:
 475         qemu_log_mask(LOG_GUEST_ERROR,
 476                       "itc_storage_write: Bad ITC View %d\n", (int)view);
 477         break;
 478     }
 479
 480 }
 481
 482 static const MemoryRegionOps itc_storage_ops = {
 483     .read = itc_storage_read,
 484     .write = itc_storage_write,
 485     .endianness = DEVICE_NATIVE_ENDIAN,
 486 };
 487
 488 static void itc_reset_cells(MIPSITUState *s)
 489 {
 490     int i;
 491
 492     memset(s->cell, 0, get_num_cells(s) * sizeof(s->cell[0]));
 493
 494     for (i = 0; i < s->num_fifo; i++) {
 495         s->cell[i].tag.E = 1;
 496         s->cell[i].tag.FIFO = 1;
 497         s->cell[i].tag.FIFODepth = ITC_CELL_DEPTH_SHIFT;
 498     }
 499 }
 500
 501 static void mips_itu_init(Object *obj)
 502 {
 503     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
 504     MIPSITUState *s = MIPS_ITU(obj);
 505
 506     memory_region_init_io(&s->storage_io, OBJECT(s), &itc_storage_ops, s,
 507                           "mips-itc-storage", ITC_STORAGE_ADDRSPACE_SZ);
 508     sysbus_init_mmio(sbd, &s->storage_io);
 509
 510     memory_region_init_io(&s->tag_io, OBJECT(s), &itc_tag_ops, s,
 511                           "mips-itc-tag", ITC_TAG_ADDRSPACE_SZ);
 512 }
 513
 514 static void mips_itu_realize(DeviceState *dev, Error **errp)
 515 {
 516     MIPSITUState *s = MIPS_ITU(dev);
 517
 518     if (s->num_fifo > ITC_FIFO_NUM_MAX) {
 519         error_setg(errp, "Exceed maximum number of FIFO cells: %d",
 520                    s->num_fifo);
 521         return;
 522     }
 523     if (s->num_semaphores > ITC_SEMAPH_NUM_MAX) {
 524         error_setg(errp, "Exceed maximum number of Semaphore cells: %d",
 525                    s->num_semaphores);
 526         return;
 527     }
 528
 529     s->cell = g_new(ITCStorageCell, get_num_cells(s));
 530 }
 531
 532 static void mips_itu_reset(DeviceState *dev)
 533 {
 534     MIPSITUState *s = MIPS_ITU(dev);
 535
 536     if (s->saar_present) {
 537         *(uint64_t *) s->saar = 0x11 << 1;
 538         s->icr0 = get_num_cells(s) << ITC_ICR0_CELL_NUM;
 539     } else {
 540         s->ITCAddressMap[0] = 0;
 541         s->ITCAddressMap[1] =
 542             ((ITC_STORAGE_ADDRSPACE_SZ - 1) & ITC_AM1_ADDR_MASK_MASK) |
 543             (get_num_cells(s) << ITC_AM1_NUMENTRIES_OFS);
 544     }
 545     itc_reconfigure(s);
 546
 547     itc_reset_cells(s);
 548 }
 549
 550 static Property mips_itu_properties[] = {
 551     DEFINE_PROP_INT32("num-fifo", MIPSITUState, num_fifo,
 552                       ITC_FIFO_NUM_MAX),
 553     DEFINE_PROP_INT32("num-semaphores", MIPSITUState, num_semaphores,
 554                       ITC_SEMAPH_NUM_MAX),
 555     DEFINE_PROP_BOOL("saar-present", MIPSITUState, saar_present, false),
 556     DEFINE_PROP_END_OF_LIST(),
 557 };
 558
 559 static void mips_itu_class_init(ObjectClass *klass, void *data)
 560 {
 561     DeviceClass *dc = DEVICE_CLASS(klass);
 562
 563     device_class_set_props(dc, mips_itu_properties);
 564     dc->realize = mips_itu_realize;
 565     dc->reset = mips_itu_reset;
 566 }
 567
 568 static const TypeInfo mips_itu_info = {
 569     .name          = TYPE_MIPS_ITU,
 570     .parent        = TYPE_SYS_BUS_DEVICE,
 571     .instance_size = sizeof(MIPSITUState),
 572     .instance_init = mips_itu_init,
 573     .class_init    = mips_itu_class_init,
 574 };
 575
 576 static void mips_itu_register_types(void)
 577 {
 578     type_register_static(&mips_itu_info);
 579 }
 580
 581 type_init(mips_itu_register_types)