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