hw/riscv/sifive_plic.c

   1 /*
   2  * SiFive PLIC (Platform Level Interrupt Controller)
   3  *
   4  * Copyright (c) 2017 SiFive, Inc.
   5  *
   6  * This provides a parameterizable interrupt controller based on SiFive's PLIC.
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2 or later, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "qemu/log.h"
  23 #include "qemu/error-report.h"
  24 #include "hw/sysbus.h"
  25 #include "target/riscv/cpu.h"
  26 #include "hw/riscv/sifive_plic.h"
  27
  28 #define RISCV_DEBUG_PLIC 0
  29
  30 static PLICMode char_to_mode(char c)
  31 {
  32     switch (c) {
  33     case 'U': return PLICMode_U;
  34     case 'S': return PLICMode_S;
  35     case 'H': return PLICMode_H;
  36     case 'M': return PLICMode_M;
  37     default:
  38         error_report("plic: invalid mode '%c'", c);
  39         exit(1);
  40     }
  41 }
  42
  43 static char mode_to_char(PLICMode m)
  44 {
  45     switch (m) {
  46     case PLICMode_U: return 'U';
  47     case PLICMode_S: return 'S';
  48     case PLICMode_H: return 'H';
  49     case PLICMode_M: return 'M';
  50     default: return '?';
  51     }
  52 }
  53
  54 static void sifive_plic_print_state(SiFivePLICState *plic)
  55 {
  56     int i;
  57     int addrid;
  58
  59     /* pending */
  60     qemu_log("pending       : ");
  61     for (i = plic->bitfield_words - 1; i >= 0; i--) {
  62         qemu_log("%08x", plic->pending[i]);
  63     }
  64     qemu_log("\n");
  65
  66     /* pending */
  67     qemu_log("claimed       : ");
  68     for (i = plic->bitfield_words - 1; i >= 0; i--) {
  69         qemu_log("%08x", plic->claimed[i]);
  70     }
  71     qemu_log("\n");
  72
  73     for (addrid = 0; addrid < plic->num_addrs; addrid++) {
  74         qemu_log("hart%d-%c enable: ",
  75             plic->addr_config[addrid].hartid,
  76             mode_to_char(plic->addr_config[addrid].mode));
  77         for (i = plic->bitfield_words - 1; i >= 0; i--) {
  78             qemu_log("%08x", plic->enable[addrid * plic->bitfield_words + i]);
  79         }
  80         qemu_log("\n");
  81     }
  82 }
  83
  84 static uint32_t atomic_set_masked(uint32_t *a, uint32_t mask, uint32_t value)
  85 {
  86     uint32_t old, new, cmp = atomic_read(a);
  87
  88     do {
  89         old = cmp;
  90         new = (old & ~mask) | (value & mask);
  91         cmp = atomic_cmpxchg(a, old, new);
  92     } while (old != cmp);
  93
  94     return old;
  95 }
  96
  97 static void sifive_plic_set_pending(SiFivePLICState *plic, int irq, bool level)
  98 {
  99     atomic_set_masked(&plic->pending[irq >> 5], 1 << (irq & 31), -!!level);
 100 }
 101
 102 static void sifive_plic_set_claimed(SiFivePLICState *plic, int irq, bool level)
 103 {
 104     atomic_set_masked(&plic->claimed[irq >> 5], 1 << (irq & 31), -!!level);
 105 }
 106
 107 static int sifive_plic_irqs_pending(SiFivePLICState *plic, uint32_t addrid)
 108 {
 109     int i, j;
 110     for (i = 0; i < plic->bitfield_words; i++) {
 111         uint32_t pending_enabled_not_claimed =
 112             (plic->pending[i] & ~plic->claimed[i]) &
 113             plic->enable[addrid * plic->bitfield_words + i];
 114         if (!pending_enabled_not_claimed) {
 115             continue;
 116         }
 117         for (j = 0; j < 32; j++) {
 118             int irq = (i << 5) + j;
 119             uint32_t prio = plic->source_priority[irq];
 120             int enabled = pending_enabled_not_claimed & (1 << j);
 121             if (enabled && prio > plic->target_priority[addrid]) {
 122                 return 1;
 123             }
 124         }
 125     }
 126     return 0;
 127 }
 128
 129 static void sifive_plic_update(SiFivePLICState *plic)
 130 {
 131     int addrid;
 132
 133     /* raise irq on harts where this irq is enabled */
 134     for (addrid = 0; addrid < plic->num_addrs; addrid++) {
 135         uint32_t hartid = plic->addr_config[addrid].hartid;
 136         PLICMode mode = plic->addr_config[addrid].mode;
 137         CPUState *cpu = qemu_get_cpu(hartid);
 138         CPURISCVState *env = cpu ? cpu->env_ptr : NULL;
 139         if (!env) {
 140             continue;
 141         }
 142         int level = sifive_plic_irqs_pending(plic, addrid);
 143         switch (mode) {
 144         case PLICMode_M:
 145             riscv_set_local_interrupt(RISCV_CPU(cpu), MIP_MEIP, level);
 146             break;
 147         case PLICMode_S:
 148             riscv_set_local_interrupt(RISCV_CPU(cpu), MIP_SEIP, level);
 149             break;
 150         default:
 151             break;
 152         }
 153     }
 154
 155     if (RISCV_DEBUG_PLIC) {
 156         sifive_plic_print_state(plic);
 157     }
 158 }
 159
 160 void sifive_plic_raise_irq(SiFivePLICState *plic, uint32_t irq)
 161 {
 162     sifive_plic_set_pending(plic, irq, true);
 163     sifive_plic_update(plic);
 164 }
 165
 166 void sifive_plic_lower_irq(SiFivePLICState *plic, uint32_t irq)
 167 {
 168     sifive_plic_set_pending(plic, irq, false);
 169     sifive_plic_update(plic);
 170 }
 171
 172 static uint32_t sifive_plic_claim(SiFivePLICState *plic, uint32_t addrid)
 173 {
 174     int i, j;
 175     for (i = 0; i < plic->bitfield_words; i++) {
 176         uint32_t pending_enabled_not_claimed =
 177             (plic->pending[i] & ~plic->claimed[i]) &
 178             plic->enable[addrid * plic->bitfield_words + i];
 179         if (!pending_enabled_not_claimed) {
 180             continue;
 181         }
 182         for (j = 0; j < 32; j++) {
 183             int irq = (i << 5) + j;
 184             uint32_t prio = plic->source_priority[irq];
 185             int enabled = pending_enabled_not_claimed & (1 << j);
 186             if (enabled && prio > plic->target_priority[addrid]) {
 187                 sifive_plic_set_pending(plic, irq, false);
 188                 sifive_plic_set_claimed(plic, irq, true);
 189                 return irq;
 190             }
 191         }
 192     }
 193     return 0;
 194 }
 195
 196 static uint64_t sifive_plic_read(void *opaque, hwaddr addr, unsigned size)
 197 {
 198     SiFivePLICState *plic = opaque;
 199
 200     /* writes must be 4 byte words */
 201     if ((addr & 0x3) != 0) {
 202         goto err;
 203     }
 204
 205     if (addr >= plic->priority_base && /* 4 bytes per source */
 206         addr < plic->priority_base + (plic->num_sources << 2))
 207     {
 208         uint32_t irq = (addr - plic->priority_base) >> 2;
 209         if (RISCV_DEBUG_PLIC) {
 210             qemu_log("plic: read priority: irq=%d priority=%d\n",
 211                 irq, plic->source_priority[irq]);
 212         }
 213         return plic->source_priority[irq];
 214     } else if (addr >= plic->pending_base && /* 1 bit per source */
 215                addr < plic->pending_base + (plic->num_sources >> 3))
 216     {
 217         uint32_t word = (addr - plic->priority_base) >> 2;
 218         if (RISCV_DEBUG_PLIC) {
 219             qemu_log("plic: read pending: word=%d value=%d\n",
 220                 word, plic->pending[word]);
 221         }
 222         return plic->pending[word];
 223     } else if (addr >= plic->enable_base && /* 1 bit per source */
 224              addr < plic->enable_base + plic->num_addrs * plic->enable_stride)
 225     {
 226         uint32_t addrid = (addr - plic->enable_base) / plic->enable_stride;
 227         uint32_t wordid = (addr & (plic->enable_stride - 1)) >> 2;
 228         if (wordid < plic->bitfield_words) {
 229             if (RISCV_DEBUG_PLIC) {
 230                 qemu_log("plic: read enable: hart%d-%c word=%d value=%x\n",
 231                     plic->addr_config[addrid].hartid,
 232                     mode_to_char(plic->addr_config[addrid].mode), wordid,
 233                     plic->enable[addrid * plic->bitfield_words + wordid]);
 234             }
 235             return plic->enable[addrid * plic->bitfield_words + wordid];
 236         }
 237     } else if (addr >= plic->context_base && /* 1 bit per source */
 238              addr < plic->context_base + plic->num_addrs * plic->context_stride)
 239     {
 240         uint32_t addrid = (addr - plic->context_base) / plic->context_stride;
 241         uint32_t contextid = (addr & (plic->context_stride - 1));
 242         if (contextid == 0) {
 243             if (RISCV_DEBUG_PLIC) {
 244                 qemu_log("plic: read priority: hart%d-%c priority=%x\n",
 245                     plic->addr_config[addrid].hartid,
 246                     mode_to_char(plic->addr_config[addrid].mode),
 247                     plic->target_priority[addrid]);
 248             }
 249             return plic->target_priority[addrid];
 250         } else if (contextid == 4) {
 251             uint32_t value = sifive_plic_claim(plic, addrid);
 252             if (RISCV_DEBUG_PLIC) {
 253                 qemu_log("plic: read claim: hart%d-%c irq=%x\n",
 254                     plic->addr_config[addrid].hartid,
 255                     mode_to_char(plic->addr_config[addrid].mode),
 256                     value);
 257                 sifive_plic_print_state(plic);
 258             }
 259             return value;
 260         }
 261     }
 262
 263 err:
 264     error_report("plic: invalid register read: %08x", (uint32_t)addr);
 265     return 0;
 266 }
 267
 268 static void sifive_plic_write(void *opaque, hwaddr addr, uint64_t value,
 269         unsigned size)
 270 {
 271     SiFivePLICState *plic = opaque;
 272
 273     /* writes must be 4 byte words */
 274     if ((addr & 0x3) != 0) {
 275         goto err;
 276     }
 277
 278     if (addr >= plic->priority_base && /* 4 bytes per source */
 279         addr < plic->priority_base + (plic->num_sources << 2))
 280     {
 281         uint32_t irq = (addr - plic->priority_base) >> 2;
 282         plic->source_priority[irq] = value & 7;
 283         if (RISCV_DEBUG_PLIC) {
 284             qemu_log("plic: write priority: irq=%d priority=%d\n",
 285                 irq, plic->source_priority[irq]);
 286         }
 287         return;
 288     } else if (addr >= plic->pending_base && /* 1 bit per source */
 289                addr < plic->pending_base + (plic->num_sources >> 3))
 290     {
 291         error_report("plic: invalid pending write: %08x", (uint32_t)addr);
 292         return;
 293     } else if (addr >= plic->enable_base && /* 1 bit per source */
 294         addr < plic->enable_base + plic->num_addrs * plic->enable_stride)
 295     {
 296         uint32_t addrid = (addr - plic->enable_base) / plic->enable_stride;
 297         uint32_t wordid = (addr & (plic->enable_stride - 1)) >> 2;
 298         if (wordid < plic->bitfield_words) {
 299             plic->enable[addrid * plic->bitfield_words + wordid] = value;
 300             if (RISCV_DEBUG_PLIC) {
 301                 qemu_log("plic: write enable: hart%d-%c word=%d value=%x\n",
 302                     plic->addr_config[addrid].hartid,
 303                     mode_to_char(plic->addr_config[addrid].mode), wordid,
 304                     plic->enable[addrid * plic->bitfield_words + wordid]);
 305             }
 306             return;
 307         }
 308     } else if (addr >= plic->context_base && /* 4 bytes per reg */
 309         addr < plic->context_base + plic->num_addrs * plic->context_stride)
 310     {
 311         uint32_t addrid = (addr - plic->context_base) / plic->context_stride;
 312         uint32_t contextid = (addr & (plic->context_stride - 1));
 313         if (contextid == 0) {
 314             if (RISCV_DEBUG_PLIC) {
 315                 qemu_log("plic: write priority: hart%d-%c priority=%x\n",
 316                     plic->addr_config[addrid].hartid,
 317                     mode_to_char(plic->addr_config[addrid].mode),
 318                     plic->target_priority[addrid]);
 319             }
 320             if (value <= plic->num_priorities) {
 321                 plic->target_priority[addrid] = value;
 322                 sifive_plic_update(plic);
 323             }
 324             return;
 325         } else if (contextid == 4) {
 326             if (RISCV_DEBUG_PLIC) {
 327                 qemu_log("plic: write claim: hart%d-%c irq=%x\n",
 328                     plic->addr_config[addrid].hartid,
 329                     mode_to_char(plic->addr_config[addrid].mode),
 330                     (uint32_t)value);
 331             }
 332             if (value < plic->num_sources) {
 333                 sifive_plic_set_claimed(plic, value, false);
 334                 sifive_plic_update(plic);
 335             }
 336             return;
 337         }
 338     }
 339
 340 err:
 341     error_report("plic: invalid register write: %08x", (uint32_t)addr);
 342 }
 343
 344 static const MemoryRegionOps sifive_plic_ops = {
 345     .read = sifive_plic_read,
 346     .write = sifive_plic_write,
 347     .endianness = DEVICE_LITTLE_ENDIAN,
 348     .valid = {
 349         .min_access_size = 4,
 350         .max_access_size = 4
 351     }
 352 };
 353
 354 static Property sifive_plic_properties[] = {
 355     DEFINE_PROP_STRING("hart-config", SiFivePLICState, hart_config),
 356     DEFINE_PROP_UINT32("num-sources", SiFivePLICState, num_sources, 0),
 357     DEFINE_PROP_UINT32("num-priorities", SiFivePLICState, num_priorities, 0),
 358     DEFINE_PROP_UINT32("priority-base", SiFivePLICState, priority_base, 0),
 359     DEFINE_PROP_UINT32("pending-base", SiFivePLICState, pending_base, 0),
 360     DEFINE_PROP_UINT32("enable-base", SiFivePLICState, enable_base, 0),
 361     DEFINE_PROP_UINT32("enable-stride", SiFivePLICState, enable_stride, 0),
 362     DEFINE_PROP_UINT32("context-base", SiFivePLICState, context_base, 0),
 363     DEFINE_PROP_UINT32("context-stride", SiFivePLICState, context_stride, 0),
 364     DEFINE_PROP_UINT32("aperture-size", SiFivePLICState, aperture_size, 0),
 365     DEFINE_PROP_END_OF_LIST(),
 366 };
 367
 368 /*
 369  * parse PLIC hart/mode address offset config
 370  *
 371  * "M"              1 hart with M mode
 372  * "MS,MS"          2 harts, 0-1 with M and S mode
 373  * "M,MS,MS,MS,MS"  5 harts, 0 with M mode, 1-5 with M and S mode
 374  */
 375 static void parse_hart_config(SiFivePLICState *plic)
 376 {
 377     int addrid, hartid, modes;
 378     const char *p;
 379     char c;
 380
 381     /* count and validate hart/mode combinations */
 382     addrid = 0, hartid = 0, modes = 0;
 383     p = plic->hart_config;
 384     while ((c = *p++)) {
 385         if (c == ',') {
 386             addrid += __builtin_popcount(modes);
 387             modes = 0;
 388             hartid++;
 389         } else {
 390             int m = 1 << char_to_mode(c);
 391             if (modes == (modes | m)) {
 392                 error_report("plic: duplicate mode '%c' in config: %s",
 393                              c, plic->hart_config);
 394                 exit(1);
 395             }
 396             modes |= m;
 397         }
 398     }
 399     if (modes) {
 400         addrid += __builtin_popcount(modes);
 401     }
 402     hartid++;
 403
 404     /* store hart/mode combinations */
 405     plic->num_addrs = addrid;
 406     plic->addr_config = g_new(PLICAddr, plic->num_addrs);
 407     addrid = 0, hartid = 0;
 408     p = plic->hart_config;
 409     while ((c = *p++)) {
 410         if (c == ',') {
 411             hartid++;
 412         } else {
 413             plic->addr_config[addrid].addrid = addrid;
 414             plic->addr_config[addrid].hartid = hartid;
 415             plic->addr_config[addrid].mode = char_to_mode(c);
 416             addrid++;
 417         }
 418     }
 419 }
 420
 421 static void sifive_plic_irq_request(void *opaque, int irq, int level)
 422 {
 423     SiFivePLICState *plic = opaque;
 424     if (RISCV_DEBUG_PLIC) {
 425         qemu_log("sifive_plic_irq_request: irq=%d level=%d\n", irq, level);
 426     }
 427     sifive_plic_set_pending(plic, irq, level > 0);
 428     sifive_plic_update(plic);
 429 }
 430
 431 static void sifive_plic_realize(DeviceState *dev, Error **errp)
 432 {
 433     SiFivePLICState *plic = SIFIVE_PLIC(dev);
 434
 435     memory_region_init_io(&plic->mmio, OBJECT(dev), &sifive_plic_ops, plic,
 436                           TYPE_SIFIVE_PLIC, plic->aperture_size);
 437     parse_hart_config(plic);
 438     plic->bitfield_words = (plic->num_sources + 31) >> 5;
 439     plic->source_priority = g_new0(uint32_t, plic->num_sources);
 440     plic->target_priority = g_new(uint32_t, plic->num_addrs);
 441     plic->pending = g_new0(uint32_t, plic->bitfield_words);
 442     plic->claimed = g_new0(uint32_t, plic->bitfield_words);
 443     plic->enable = g_new0(uint32_t, plic->bitfield_words * plic->num_addrs);
 444     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &plic->mmio);
 445     qdev_init_gpio_in(dev, sifive_plic_irq_request, plic->num_sources);
 446 }
 447
 448 static void sifive_plic_class_init(ObjectClass *klass, void *data)
 449 {
 450     DeviceClass *dc = DEVICE_CLASS(klass);
 451
 452     dc->props = sifive_plic_properties;
 453     dc->realize = sifive_plic_realize;
 454 }
 455
 456 static const TypeInfo sifive_plic_info = {
 457     .name          = TYPE_SIFIVE_PLIC,
 458     .parent        = TYPE_SYS_BUS_DEVICE,
 459     .instance_size = sizeof(SiFivePLICState),
 460     .class_init    = sifive_plic_class_init,
 461 };
 462
 463 static void sifive_plic_register_types(void)
 464 {
 465     type_register_static(&sifive_plic_info);
 466 }
 467
 468 type_init(sifive_plic_register_types)
 469
 470 /*
 471  * Create PLIC device.
 472  */
 473 DeviceState *sifive_plic_create(hwaddr addr, char *hart_config,
 474     uint32_t num_sources, uint32_t num_priorities,
 475     uint32_t priority_base, uint32_t pending_base,
 476     uint32_t enable_base, uint32_t enable_stride,
 477     uint32_t context_base, uint32_t context_stride,
 478     uint32_t aperture_size)
 479 {
 480     DeviceState *dev = qdev_create(NULL, TYPE_SIFIVE_PLIC);
 481     assert(enable_stride == (enable_stride & -enable_stride));
 482     assert(context_stride == (context_stride & -context_stride));
 483     qdev_prop_set_string(dev, "hart-config", hart_config);
 484     qdev_prop_set_uint32(dev, "num-sources", num_sources);
 485     qdev_prop_set_uint32(dev, "num-priorities", num_priorities);
 486     qdev_prop_set_uint32(dev, "priority-base", priority_base);
 487     qdev_prop_set_uint32(dev, "pending-base", pending_base);
 488     qdev_prop_set_uint32(dev, "enable-base", enable_base);
 489     qdev_prop_set_uint32(dev, "enable-stride", enable_stride);
 490     qdev_prop_set_uint32(dev, "context-base", context_base);
 491     qdev_prop_set_uint32(dev, "context-stride", context_stride);
 492     qdev_prop_set_uint32(dev, "aperture-size", aperture_size);
 493     qdev_init_nofail(dev);
 494     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, addr);
 495     return dev;
 496 }