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