hw/intc/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 "qapi/error.h"
  23 #include "qemu/log.h"
  24 #include "qemu/module.h"
  25 #include "qemu/error-report.h"
  26 #include "hw/sysbus.h"
  27 #include "hw/pci/msi.h"
  28 #include "hw/qdev-properties.h"
  29 #include "hw/intc/sifive_plic.h"
  30 #include "target/riscv/cpu.h"
  31 #include "migration/vmstate.h"
  32 #include "hw/irq.h"
  33
  34 #define RISCV_DEBUG_PLIC 0
  35
  36 static PLICMode char_to_mode(char c)
  37 {
  38     switch (c) {
  39     case 'U': return PLICMode_U;
  40     case 'S': return PLICMode_S;
  41     case 'H': return PLICMode_H;
  42     case 'M': return PLICMode_M;
  43     default:
  44         error_report("plic: invalid mode '%c'", c);
  45         exit(1);
  46     }
  47 }
  48
  49 static char mode_to_char(PLICMode m)
  50 {
  51     switch (m) {
  52     case PLICMode_U: return 'U';
  53     case PLICMode_S: return 'S';
  54     case PLICMode_H: return 'H';
  55     case PLICMode_M: return 'M';
  56     default: return '?';
  57     }
  58 }
  59
  60 static void sifive_plic_print_state(SiFivePLICState *plic)
  61 {
  62     int i;
  63     int addrid;
  64
  65     /* pending */
  66     qemu_log("pending       : ");
  67     for (i = plic->bitfield_words - 1; i >= 0; i--) {
  68         qemu_log("%08x", plic->pending[i]);
  69     }
  70     qemu_log("\n");
  71
  72     /* pending */
  73     qemu_log("claimed       : ");
  74     for (i = plic->bitfield_words - 1; i >= 0; i--) {
  75         qemu_log("%08x", plic->claimed[i]);
  76     }
  77     qemu_log("\n");
  78
  79     for (addrid = 0; addrid < plic->num_addrs; addrid++) {
  80         qemu_log("hart%d-%c enable: ",
  81             plic->addr_config[addrid].hartid,
  82             mode_to_char(plic->addr_config[addrid].mode));
  83         for (i = plic->bitfield_words - 1; i >= 0; i--) {
  84             qemu_log("%08x", plic->enable[addrid * plic->bitfield_words + i]);
  85         }
  86         qemu_log("\n");
  87     }
  88 }
  89
  90 static uint32_t atomic_set_masked(uint32_t *a, uint32_t mask, uint32_t value)
  91 {
  92     uint32_t old, new, cmp = qatomic_read(a);
  93
  94     do {
  95         old = cmp;
  96         new = (old & ~mask) | (value & mask);
  97         cmp = qatomic_cmpxchg(a, old, new);
  98     } while (old != cmp);
  99
 100     return old;
 101 }
 102
 103 static void sifive_plic_set_pending(SiFivePLICState *plic, int irq, bool level)
 104 {
 105     atomic_set_masked(&plic->pending[irq >> 5], 1 << (irq & 31), -!!level);
 106 }
 107
 108 static void sifive_plic_set_claimed(SiFivePLICState *plic, int irq, bool level)
 109 {
 110     atomic_set_masked(&plic->claimed[irq >> 5], 1 << (irq & 31), -!!level);
 111 }
 112
 113 static int sifive_plic_irqs_pending(SiFivePLICState *plic, uint32_t addrid)
 114 {
 115     int i, j;
 116     for (i = 0; i < plic->bitfield_words; i++) {
 117         uint32_t pending_enabled_not_claimed =
 118             (plic->pending[i] & ~plic->claimed[i]) &
 119             plic->enable[addrid * plic->bitfield_words + i];
 120         if (!pending_enabled_not_claimed) {
 121             continue;
 122         }
 123         for (j = 0; j < 32; j++) {
 124             int irq = (i << 5) + j;
 125             uint32_t prio = plic->source_priority[irq];
 126             int enabled = pending_enabled_not_claimed & (1 << j);
 127             if (enabled && prio > plic->target_priority[addrid]) {
 128                 return 1;
 129             }
 130         }
 131     }
 132     return 0;
 133 }
 134
 135 static void sifive_plic_update(SiFivePLICState *plic)
 136 {
 137     int addrid;
 138
 139     /* raise irq on harts where this irq is enabled */
 140     for (addrid = 0; addrid < plic->num_addrs; addrid++) {
 141         uint32_t hartid = plic->addr_config[addrid].hartid;
 142         PLICMode mode = plic->addr_config[addrid].mode;
 143         int level = sifive_plic_irqs_pending(plic, addrid);
 144
 145         switch (mode) {
 146         case PLICMode_M:
 147             qemu_set_irq(plic->m_external_irqs[hartid - plic->hartid_base], level);
 148             break;
 149         case PLICMode_S:
 150             qemu_set_irq(plic->s_external_irqs[hartid - plic->hartid_base], level);
 151             break;
 152         default:
 153             break;
 154         }
 155     }
 156
 157     if (RISCV_DEBUG_PLIC) {
 158         sifive_plic_print_state(plic);
 159     }
 160 }
 161
 162 static uint32_t sifive_plic_claim(SiFivePLICState *plic, uint32_t addrid)
 163 {
 164     int i, j;
 165     uint32_t max_irq = 0;
 166     uint32_t max_prio = plic->target_priority[addrid];
 167
 168     for (i = 0; i < plic->bitfield_words; i++) {
 169         uint32_t pending_enabled_not_claimed =
 170             (plic->pending[i] & ~plic->claimed[i]) &
 171             plic->enable[addrid * plic->bitfield_words + i];
 172         if (!pending_enabled_not_claimed) {
 173             continue;
 174         }
 175         for (j = 0; j < 32; j++) {
 176             int irq = (i << 5) + j;
 177             uint32_t prio = plic->source_priority[irq];
 178             int enabled = pending_enabled_not_claimed & (1 << j);
 179             if (enabled && prio > max_prio) {
 180                 max_irq = irq;
 181                 max_prio = prio;
 182             }
 183         }
 184     }
 185
 186     if (max_irq) {
 187         sifive_plic_set_pending(plic, max_irq, false);
 188         sifive_plic_set_claimed(plic, max_irq, true);
 189     }
 190     return max_irq;
 191 }
 192
 193 static uint64_t sifive_plic_read(void *opaque, hwaddr addr, unsigned size)
 194 {
 195     SiFivePLICState *plic = opaque;
 196
 197     /* writes must be 4 byte words */
 198     if ((addr & 0x3) != 0) {
 199         goto err;
 200     }
 201
 202     if (addr >= plic->priority_base && /* 4 bytes per source */
 203         addr < plic->priority_base + (plic->num_sources << 2))
 204     {
 205         uint32_t irq = ((addr - plic->priority_base) >> 2) + 1;
 206         if (RISCV_DEBUG_PLIC) {
 207             qemu_log("plic: read priority: irq=%d priority=%d\n",
 208                 irq, plic->source_priority[irq]);
 209         }
 210         return plic->source_priority[irq];
 211     } else if (addr >= plic->pending_base && /* 1 bit per source */
 212                addr < plic->pending_base + (plic->num_sources >> 3))
 213     {
 214         uint32_t word = (addr - plic->pending_base) >> 2;
 215         if (RISCV_DEBUG_PLIC) {
 216             qemu_log("plic: read pending: word=%d value=%d\n",
 217                 word, plic->pending[word]);
 218         }
 219         return plic->pending[word];
 220     } else if (addr >= plic->enable_base && /* 1 bit per source */
 221              addr < plic->enable_base + plic->num_addrs * plic->enable_stride)
 222     {
 223         uint32_t addrid = (addr - plic->enable_base) / plic->enable_stride;
 224         uint32_t wordid = (addr & (plic->enable_stride - 1)) >> 2;
 225         if (wordid < plic->bitfield_words) {
 226             if (RISCV_DEBUG_PLIC) {
 227                 qemu_log("plic: read enable: hart%d-%c word=%d value=%x\n",
 228                     plic->addr_config[addrid].hartid,
 229                     mode_to_char(plic->addr_config[addrid].mode), wordid,
 230                     plic->enable[addrid * plic->bitfield_words + wordid]);
 231             }
 232             return plic->enable[addrid * plic->bitfield_words + wordid];
 233         }
 234     } else if (addr >= plic->context_base && /* 1 bit per source */
 235              addr < plic->context_base + plic->num_addrs * plic->context_stride)
 236     {
 237         uint32_t addrid = (addr - plic->context_base) / plic->context_stride;
 238         uint32_t contextid = (addr & (plic->context_stride - 1));
 239         if (contextid == 0) {
 240             if (RISCV_DEBUG_PLIC) {
 241                 qemu_log("plic: read priority: hart%d-%c priority=%x\n",
 242                     plic->addr_config[addrid].hartid,
 243                     mode_to_char(plic->addr_config[addrid].mode),
 244                     plic->target_priority[addrid]);
 245             }
 246             return plic->target_priority[addrid];
 247         } else if (contextid == 4) {
 248             uint32_t value = sifive_plic_claim(plic, addrid);
 249             if (RISCV_DEBUG_PLIC) {
 250                 qemu_log("plic: read claim: hart%d-%c irq=%x\n",
 251                     plic->addr_config[addrid].hartid,
 252                     mode_to_char(plic->addr_config[addrid].mode),
 253                     value);
 254             }
 255             sifive_plic_update(plic);
 256             return value;
 257         }
 258     }
 259
 260 err:
 261     qemu_log_mask(LOG_GUEST_ERROR,
 262                   "%s: Invalid register read 0x%" HWADDR_PRIx "\n",
 263                   __func__, addr);
 264     return 0;
 265 }
 266
 267 static void sifive_plic_write(void *opaque, hwaddr addr, uint64_t value,
 268         unsigned size)
 269 {
 270     SiFivePLICState *plic = opaque;
 271
 272     /* writes must be 4 byte words */
 273     if ((addr & 0x3) != 0) {
 274         goto err;
 275     }
 276
 277     if (addr >= plic->priority_base && /* 4 bytes per source */
 278         addr < plic->priority_base + (plic->num_sources << 2))
 279     {
 280         uint32_t irq = ((addr - plic->priority_base) >> 2) + 1;
 281         plic->source_priority[irq] = value & 7;
 282         if (RISCV_DEBUG_PLIC) {
 283             qemu_log("plic: write priority: irq=%d priority=%d\n",
 284                 irq, plic->source_priority[irq]);
 285         }
 286         sifive_plic_update(plic);
 287         return;
 288     } else if (addr >= plic->pending_base && /* 1 bit per source */
 289                addr < plic->pending_base + (plic->num_sources >> 3))
 290     {
 291         qemu_log_mask(LOG_GUEST_ERROR,
 292                       "%s: invalid pending write: 0x%" HWADDR_PRIx "",
 293                       __func__, addr);
 294         return;
 295     } else if (addr >= plic->enable_base && /* 1 bit per source */
 296         addr < plic->enable_base + plic->num_addrs * plic->enable_stride)
 297     {
 298         uint32_t addrid = (addr - plic->enable_base) / plic->enable_stride;
 299         uint32_t wordid = (addr & (plic->enable_stride - 1)) >> 2;
 300         if (wordid < plic->bitfield_words) {
 301             plic->enable[addrid * plic->bitfield_words + wordid] = value;
 302             if (RISCV_DEBUG_PLIC) {
 303                 qemu_log("plic: write enable: hart%d-%c word=%d value=%x\n",
 304                     plic->addr_config[addrid].hartid,
 305                     mode_to_char(plic->addr_config[addrid].mode), wordid,
 306                     plic->enable[addrid * plic->bitfield_words + wordid]);
 307             }
 308             return;
 309         }
 310     } else if (addr >= plic->context_base && /* 4 bytes per reg */
 311         addr < plic->context_base + plic->num_addrs * plic->context_stride)
 312     {
 313         uint32_t addrid = (addr - plic->context_base) / plic->context_stride;
 314         uint32_t contextid = (addr & (plic->context_stride - 1));
 315         if (contextid == 0) {
 316             if (RISCV_DEBUG_PLIC) {
 317                 qemu_log("plic: write priority: hart%d-%c priority=%x\n",
 318                     plic->addr_config[addrid].hartid,
 319                     mode_to_char(plic->addr_config[addrid].mode),
 320                     plic->target_priority[addrid]);
 321             }
 322             if (value <= plic->num_priorities) {
 323                 plic->target_priority[addrid] = value;
 324                 sifive_plic_update(plic);
 325             }
 326             return;
 327         } else if (contextid == 4) {
 328             if (RISCV_DEBUG_PLIC) {
 329                 qemu_log("plic: write claim: hart%d-%c irq=%x\n",
 330                     plic->addr_config[addrid].hartid,
 331                     mode_to_char(plic->addr_config[addrid].mode),
 332                     (uint32_t)value);
 333             }
 334             if (value < plic->num_sources) {
 335                 sifive_plic_set_claimed(plic, value, false);
 336                 sifive_plic_update(plic);
 337             }
 338             return;
 339         }
 340     }
 341
 342 err:
 343     qemu_log_mask(LOG_GUEST_ERROR,
 344                   "%s: Invalid register write 0x%" HWADDR_PRIx "\n",
 345                   __func__, addr);
 346 }
 347
 348 static const MemoryRegionOps sifive_plic_ops = {
 349     .read = sifive_plic_read,
 350     .write = sifive_plic_write,
 351     .endianness = DEVICE_LITTLE_ENDIAN,
 352     .valid = {
 353         .min_access_size = 4,
 354         .max_access_size = 4
 355     }
 356 };
 357
 358 static Property sifive_plic_properties[] = {
 359     DEFINE_PROP_STRING("hart-config", SiFivePLICState, hart_config),
 360     DEFINE_PROP_UINT32("hartid-base", SiFivePLICState, hartid_base, 0),
 361     DEFINE_PROP_UINT32("num-sources", SiFivePLICState, num_sources, 0),
 362     DEFINE_PROP_UINT32("num-priorities", SiFivePLICState, num_priorities, 0),
 363     DEFINE_PROP_UINT32("priority-base", SiFivePLICState, priority_base, 0),
 364     DEFINE_PROP_UINT32("pending-base", SiFivePLICState, pending_base, 0),
 365     DEFINE_PROP_UINT32("enable-base", SiFivePLICState, enable_base, 0),
 366     DEFINE_PROP_UINT32("enable-stride", SiFivePLICState, enable_stride, 0),
 367     DEFINE_PROP_UINT32("context-base", SiFivePLICState, context_base, 0),
 368     DEFINE_PROP_UINT32("context-stride", SiFivePLICState, context_stride, 0),
 369     DEFINE_PROP_UINT32("aperture-size", SiFivePLICState, aperture_size, 0),
 370     DEFINE_PROP_END_OF_LIST(),
 371 };
 372
 373 /*
 374  * parse PLIC hart/mode address offset config
 375  *
 376  * "M"              1 hart with M mode
 377  * "MS,MS"          2 harts, 0-1 with M and S mode
 378  * "M,MS,MS,MS,MS"  5 harts, 0 with M mode, 1-5 with M and S mode
 379  */
 380 static void parse_hart_config(SiFivePLICState *plic)
 381 {
 382     int addrid, hartid, modes;
 383     const char *p;
 384     char c;
 385
 386     /* count and validate hart/mode combinations */
 387     addrid = 0, hartid = 0, modes = 0;
 388     p = plic->hart_config;
 389     while ((c = *p++)) {
 390         if (c == ',') {
 391             addrid += ctpop8(modes);
 392             modes = 0;
 393             hartid++;
 394         } else {
 395             int m = 1 << char_to_mode(c);
 396             if (modes == (modes | m)) {
 397                 error_report("plic: duplicate mode '%c' in config: %s",
 398                              c, plic->hart_config);
 399                 exit(1);
 400             }
 401             modes |= m;
 402         }
 403     }
 404     if (modes) {
 405         addrid += ctpop8(modes);
 406     }
 407     hartid++;
 408
 409     plic->num_addrs = addrid;
 410     plic->num_harts = hartid;
 411
 412     /* store hart/mode combinations */
 413     plic->addr_config = g_new(PLICAddr, plic->num_addrs);
 414     addrid = 0, hartid = plic->hartid_base;
 415     p = plic->hart_config;
 416     while ((c = *p++)) {
 417         if (c == ',') {
 418             hartid++;
 419         } else {
 420             plic->addr_config[addrid].addrid = addrid;
 421             plic->addr_config[addrid].hartid = hartid;
 422             plic->addr_config[addrid].mode = char_to_mode(c);
 423             addrid++;
 424         }
 425     }
 426 }
 427
 428 static void sifive_plic_irq_request(void *opaque, int irq, int level)
 429 {
 430     SiFivePLICState *plic = opaque;
 431     if (RISCV_DEBUG_PLIC) {
 432         qemu_log("sifive_plic_irq_request: irq=%d level=%d\n", irq, level);
 433     }
 434     sifive_plic_set_pending(plic, irq, level > 0);
 435     sifive_plic_update(plic);
 436 }
 437
 438 static void sifive_plic_realize(DeviceState *dev, Error **errp)
 439 {
 440     SiFivePLICState *plic = SIFIVE_PLIC(dev);
 441     int i;
 442
 443     memory_region_init_io(&plic->mmio, OBJECT(dev), &sifive_plic_ops, plic,
 444                           TYPE_SIFIVE_PLIC, plic->aperture_size);
 445     parse_hart_config(plic);
 446     plic->bitfield_words = (plic->num_sources + 31) >> 5;
 447     plic->num_enables = plic->bitfield_words * plic->num_addrs;
 448     plic->source_priority = g_new0(uint32_t, plic->num_sources);
 449     plic->target_priority = g_new(uint32_t, plic->num_addrs);
 450     plic->pending = g_new0(uint32_t, plic->bitfield_words);
 451     plic->claimed = g_new0(uint32_t, plic->bitfield_words);
 452     plic->enable = g_new0(uint32_t, plic->num_enables);
 453     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &plic->mmio);
 454     qdev_init_gpio_in(dev, sifive_plic_irq_request, plic->num_sources);
 455
 456     plic->s_external_irqs = g_malloc(sizeof(qemu_irq) * plic->num_harts);
 457     qdev_init_gpio_out(dev, plic->s_external_irqs, plic->num_harts);
 458
 459     plic->m_external_irqs = g_malloc(sizeof(qemu_irq) * plic->num_harts);
 460     qdev_init_gpio_out(dev, plic->m_external_irqs, plic->num_harts);
 461
 462     /* We can't allow the supervisor to control SEIP as this would allow the
 463      * supervisor to clear a pending external interrupt which will result in
 464      * lost a interrupt in the case a PLIC is attached. The SEIP bit must be
 465      * hardware controlled when a PLIC is attached.
 466      */
 467     for (i = 0; i < plic->num_harts; i++) {
 468         RISCVCPU *cpu = RISCV_CPU(qemu_get_cpu(plic->hartid_base + i));
 469         if (riscv_cpu_claim_interrupts(cpu, MIP_SEIP) < 0) {
 470             error_report("SEIP already claimed");
 471             exit(1);
 472         }
 473     }
 474
 475     msi_nonbroken = true;
 476 }
 477
 478 static const VMStateDescription vmstate_sifive_plic = {
 479     .name = "riscv_sifive_plic",
 480     .version_id = 1,
 481     .minimum_version_id = 1,
 482     .fields = (VMStateField[]) {
 483             VMSTATE_VARRAY_UINT32(source_priority, SiFivePLICState,
 484                                   num_sources, 0,
 485                                   vmstate_info_uint32, uint32_t),
 486             VMSTATE_VARRAY_UINT32(target_priority, SiFivePLICState,
 487                                   num_addrs, 0,
 488                                   vmstate_info_uint32, uint32_t),
 489             VMSTATE_VARRAY_UINT32(pending, SiFivePLICState, bitfield_words, 0,
 490                                   vmstate_info_uint32, uint32_t),
 491             VMSTATE_VARRAY_UINT32(claimed, SiFivePLICState, bitfield_words, 0,
 492                                   vmstate_info_uint32, uint32_t),
 493             VMSTATE_VARRAY_UINT32(enable, SiFivePLICState, num_enables, 0,
 494                                   vmstate_info_uint32, uint32_t),
 495             VMSTATE_END_OF_LIST()
 496         }
 497 };
 498
 499 static void sifive_plic_class_init(ObjectClass *klass, void *data)
 500 {
 501     DeviceClass *dc = DEVICE_CLASS(klass);
 502
 503     device_class_set_props(dc, sifive_plic_properties);
 504     dc->realize = sifive_plic_realize;
 505     dc->vmsd = &vmstate_sifive_plic;
 506 }
 507
 508 static const TypeInfo sifive_plic_info = {
 509     .name          = TYPE_SIFIVE_PLIC,
 510     .parent        = TYPE_SYS_BUS_DEVICE,
 511     .instance_size = sizeof(SiFivePLICState),
 512     .class_init    = sifive_plic_class_init,
 513 };
 514
 515 static void sifive_plic_register_types(void)
 516 {
 517     type_register_static(&sifive_plic_info);
 518 }
 519
 520 type_init(sifive_plic_register_types)
 521
 522 /*
 523  * Create PLIC device.
 524  */
 525 DeviceState *sifive_plic_create(hwaddr addr, char *hart_config,
 526     uint32_t num_harts,
 527     uint32_t hartid_base, uint32_t num_sources,
 528     uint32_t num_priorities, uint32_t priority_base,
 529     uint32_t pending_base, uint32_t enable_base,
 530     uint32_t enable_stride, uint32_t context_base,
 531     uint32_t context_stride, uint32_t aperture_size)
 532 {
 533     DeviceState *dev = qdev_new(TYPE_SIFIVE_PLIC);
 534     int i;
 535
 536     assert(enable_stride == (enable_stride & -enable_stride));
 537     assert(context_stride == (context_stride & -context_stride));
 538     qdev_prop_set_string(dev, "hart-config", hart_config);
 539     qdev_prop_set_uint32(dev, "hartid-base", hartid_base);
 540     qdev_prop_set_uint32(dev, "num-sources", num_sources);
 541     qdev_prop_set_uint32(dev, "num-priorities", num_priorities);
 542     qdev_prop_set_uint32(dev, "priority-base", priority_base);
 543     qdev_prop_set_uint32(dev, "pending-base", pending_base);
 544     qdev_prop_set_uint32(dev, "enable-base", enable_base);
 545     qdev_prop_set_uint32(dev, "enable-stride", enable_stride);
 546     qdev_prop_set_uint32(dev, "context-base", context_base);
 547     qdev_prop_set_uint32(dev, "context-stride", context_stride);
 548     qdev_prop_set_uint32(dev, "aperture-size", aperture_size);
 549     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
 550     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, addr);
 551
 552     for (i = 0; i < num_harts; i++) {
 553         CPUState *cpu = qemu_get_cpu(hartid_base + i);
 554
 555         qdev_connect_gpio_out(dev, i,
 556                               qdev_get_gpio_in(DEVICE(cpu), IRQ_S_EXT));
 557         qdev_connect_gpio_out(dev, num_harts + i,
 558                               qdev_get_gpio_in(DEVICE(cpu), IRQ_M_EXT));
 559     }
 560
 561     return dev;
 562 }