hw/intc/i8259.c

   1 /*
   2  * QEMU 8259 interrupt controller emulation
   3  *
   4  * Copyright (c) 2003-2004 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu/osdep.h"
  25 #include "hw/hw.h"
  26 #include "hw/i386/pc.h"
  27 #include "hw/isa/isa.h"
  28 #include "monitor/monitor.h"
  29 #include "qemu/timer.h"
  30 #include "hw/isa/i8259_internal.h"
  31
  32 /* debug PIC */
  33 //#define DEBUG_PIC
  34
  35 #ifdef DEBUG_PIC
  36 #define DPRINTF(fmt, ...)                                       \
  37     do { printf("pic: " fmt , ## __VA_ARGS__); } while (0)
  38 #else
  39 #define DPRINTF(fmt, ...)
  40 #endif
  41
  42 //#define DEBUG_IRQ_LATENCY
  43 //#define DEBUG_IRQ_COUNT
  44
  45 #define TYPE_I8259 "isa-i8259"
  46 #define PIC_CLASS(class) OBJECT_CLASS_CHECK(PICClass, (class), TYPE_I8259)
  47 #define PIC_GET_CLASS(obj) OBJECT_GET_CLASS(PICClass, (obj), TYPE_I8259)
  48
  49 /**
  50  * PICClass:
  51  * @parent_realize: The parent's realizefn.
  52  */
  53 typedef struct PICClass {
  54     PICCommonClass parent_class;
  55
  56     DeviceRealize parent_realize;
  57 } PICClass;
  58
  59 #if defined(DEBUG_PIC) || defined(DEBUG_IRQ_COUNT)
  60 static int irq_level[16];
  61 #endif
  62 #ifdef DEBUG_IRQ_COUNT
  63 static uint64_t irq_count[16];
  64 #endif
  65 #ifdef DEBUG_IRQ_LATENCY
  66 static int64_t irq_time[16];
  67 #endif
  68 DeviceState *isa_pic;
  69 static PICCommonState *slave_pic;
  70
  71 /* return the highest priority found in mask (highest = smallest
  72    number). Return 8 if no irq */
  73 static int get_priority(PICCommonState *s, int mask)
  74 {
  75     int priority;
  76
  77     if (mask == 0) {
  78         return 8;
  79     }
  80     priority = 0;
  81     while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0) {
  82         priority++;
  83     }
  84     return priority;
  85 }
  86
  87 /* return the pic wanted interrupt. return -1 if none */
  88 static int pic_get_irq(PICCommonState *s)
  89 {
  90     int mask, cur_priority, priority;
  91
  92     mask = s->irr & ~s->imr;
  93     priority = get_priority(s, mask);
  94     if (priority == 8) {
  95         return -1;
  96     }
  97     /* compute current priority. If special fully nested mode on the
  98        master, the IRQ coming from the slave is not taken into account
  99        for the priority computation. */
 100     mask = s->isr;
 101     if (s->special_mask) {
 102         mask &= ~s->imr;
 103     }
 104     if (s->special_fully_nested_mode && s->master) {
 105         mask &= ~(1 << 2);
 106     }
 107     cur_priority = get_priority(s, mask);
 108     if (priority < cur_priority) {
 109         /* higher priority found: an irq should be generated */
 110         return (priority + s->priority_add) & 7;
 111     } else {
 112         return -1;
 113     }
 114 }
 115
 116 /* Update INT output. Must be called every time the output may have changed. */
 117 static void pic_update_irq(PICCommonState *s)
 118 {
 119     int irq;
 120
 121     irq = pic_get_irq(s);
 122     if (irq >= 0) {
 123         DPRINTF("pic%d: imr=%x irr=%x padd=%d\n",
 124                 s->master ? 0 : 1, s->imr, s->irr, s->priority_add);
 125         qemu_irq_raise(s->int_out[0]);
 126     } else {
 127         qemu_irq_lower(s->int_out[0]);
 128     }
 129 }
 130
 131 /* set irq level. If an edge is detected, then the IRR is set to 1 */
 132 static void pic_set_irq(void *opaque, int irq, int level)
 133 {
 134     PICCommonState *s = opaque;
 135     int mask = 1 << irq;
 136
 137 #if defined(DEBUG_PIC) || defined(DEBUG_IRQ_COUNT) || \
 138     defined(DEBUG_IRQ_LATENCY)
 139     int irq_index = s->master ? irq : irq + 8;
 140 #endif
 141 #if defined(DEBUG_PIC) || defined(DEBUG_IRQ_COUNT)
 142     if (level != irq_level[irq_index]) {
 143         DPRINTF("pic_set_irq: irq=%d level=%d\n", irq_index, level);
 144         irq_level[irq_index] = level;
 145 #ifdef DEBUG_IRQ_COUNT
 146         if (level == 1) {
 147             irq_count[irq_index]++;
 148         }
 149 #endif
 150     }
 151 #endif
 152 #ifdef DEBUG_IRQ_LATENCY
 153     if (level) {
 154         irq_time[irq_index] = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 155     }
 156 #endif
 157
 158     if (s->elcr & mask) {
 159         /* level triggered */
 160         if (level) {
 161             s->irr |= mask;
 162             s->last_irr |= mask;
 163         } else {
 164             s->irr &= ~mask;
 165             s->last_irr &= ~mask;
 166         }
 167     } else {
 168         /* edge triggered */
 169         if (level) {
 170             if ((s->last_irr & mask) == 0) {
 171                 s->irr |= mask;
 172             }
 173             s->last_irr |= mask;
 174         } else {
 175             s->last_irr &= ~mask;
 176         }
 177     }
 178     pic_update_irq(s);
 179 }
 180
 181 /* acknowledge interrupt 'irq' */
 182 static void pic_intack(PICCommonState *s, int irq)
 183 {
 184     if (s->auto_eoi) {
 185         if (s->rotate_on_auto_eoi) {
 186             s->priority_add = (irq + 1) & 7;
 187         }
 188     } else {
 189         s->isr |= (1 << irq);
 190     }
 191     /* We don't clear a level sensitive interrupt here */
 192     if (!(s->elcr & (1 << irq))) {
 193         s->irr &= ~(1 << irq);
 194     }
 195     pic_update_irq(s);
 196 }
 197
 198 int pic_read_irq(DeviceState *d)
 199 {
 200     PICCommonState *s = PIC_COMMON(d);
 201     int irq, irq2, intno;
 202
 203     irq = pic_get_irq(s);
 204     if (irq >= 0) {
 205         if (irq == 2) {
 206             irq2 = pic_get_irq(slave_pic);
 207             if (irq2 >= 0) {
 208                 pic_intack(slave_pic, irq2);
 209             } else {
 210                 /* spurious IRQ on slave controller */
 211                 irq2 = 7;
 212             }
 213             intno = slave_pic->irq_base + irq2;
 214         } else {
 215             intno = s->irq_base + irq;
 216         }
 217         pic_intack(s, irq);
 218     } else {
 219         /* spurious IRQ on host controller */
 220         irq = 7;
 221         intno = s->irq_base + irq;
 222     }
 223
 224 #if defined(DEBUG_PIC) || defined(DEBUG_IRQ_LATENCY)
 225     if (irq == 2) {
 226         irq = irq2 + 8;
 227     }
 228 #endif
 229 #ifdef DEBUG_IRQ_LATENCY
 230     printf("IRQ%d latency=%0.3fus\n",
 231            irq,
 232            (double)(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) -
 233                     irq_time[irq]) * 1000000.0 / get_ticks_per_sec());
 234 #endif
 235     DPRINTF("pic_interrupt: irq=%d\n", irq);
 236     return intno;
 237 }
 238
 239 static void pic_init_reset(PICCommonState *s)
 240 {
 241     pic_reset_common(s);
 242     pic_update_irq(s);
 243 }
 244
 245 static void pic_reset(DeviceState *dev)
 246 {
 247     PICCommonState *s = PIC_COMMON(dev);
 248
 249     s->elcr = 0;
 250     pic_init_reset(s);
 251 }
 252
 253 static void pic_ioport_write(void *opaque, hwaddr addr64,
 254                              uint64_t val64, unsigned size)
 255 {
 256     PICCommonState *s = opaque;
 257     uint32_t addr = addr64;
 258     uint32_t val = val64;
 259     int priority, cmd, irq;
 260
 261     DPRINTF("write: addr=0x%02x val=0x%02x\n", addr, val);
 262     if (addr == 0) {
 263         if (val & 0x10) {
 264             pic_init_reset(s);
 265             s->init_state = 1;
 266             s->init4 = val & 1;
 267             s->single_mode = val & 2;
 268             if (val & 0x08) {
 269                 qemu_log_mask(LOG_UNIMP,
 270                               "i8259: level sensitive irq not supported\n");
 271             }
 272         } else if (val & 0x08) {
 273             if (val & 0x04) {
 274                 s->poll = 1;
 275             }
 276             if (val & 0x02) {
 277                 s->read_reg_select = val & 1;
 278             }
 279             if (val & 0x40) {
 280                 s->special_mask = (val >> 5) & 1;
 281             }
 282         } else {
 283             cmd = val >> 5;
 284             switch (cmd) {
 285             case 0:
 286             case 4:
 287                 s->rotate_on_auto_eoi = cmd >> 2;
 288                 break;
 289             case 1: /* end of interrupt */
 290             case 5:
 291                 priority = get_priority(s, s->isr);
 292                 if (priority != 8) {
 293                     irq = (priority + s->priority_add) & 7;
 294                     s->isr &= ~(1 << irq);
 295                     if (cmd == 5) {
 296                         s->priority_add = (irq + 1) & 7;
 297                     }
 298                     pic_update_irq(s);
 299                 }
 300                 break;
 301             case 3:
 302                 irq = val & 7;
 303                 s->isr &= ~(1 << irq);
 304                 pic_update_irq(s);
 305                 break;
 306             case 6:
 307                 s->priority_add = (val + 1) & 7;
 308                 pic_update_irq(s);
 309                 break;
 310             case 7:
 311                 irq = val & 7;
 312                 s->isr &= ~(1 << irq);
 313                 s->priority_add = (irq + 1) & 7;
 314                 pic_update_irq(s);
 315                 break;
 316             default:
 317                 /* no operation */
 318                 break;
 319             }
 320         }
 321     } else {
 322         switch (s->init_state) {
 323         case 0:
 324             /* normal mode */
 325             s->imr = val;
 326             pic_update_irq(s);
 327             break;
 328         case 1:
 329             s->irq_base = val & 0xf8;
 330             s->init_state = s->single_mode ? (s->init4 ? 3 : 0) : 2;
 331             break;
 332         case 2:
 333             if (s->init4) {
 334                 s->init_state = 3;
 335             } else {
 336                 s->init_state = 0;
 337             }
 338             break;
 339         case 3:
 340             s->special_fully_nested_mode = (val >> 4) & 1;
 341             s->auto_eoi = (val >> 1) & 1;
 342             s->init_state = 0;
 343             break;
 344         }
 345     }
 346 }
 347
 348 static uint64_t pic_ioport_read(void *opaque, hwaddr addr,
 349                                 unsigned size)
 350 {
 351     PICCommonState *s = opaque;
 352     int ret;
 353
 354     if (s->poll) {
 355         ret = pic_get_irq(s);
 356         if (ret >= 0) {
 357             pic_intack(s, ret);
 358             ret |= 0x80;
 359         } else {
 360             ret = 0;
 361         }
 362         s->poll = 0;
 363     } else {
 364         if (addr == 0) {
 365             if (s->read_reg_select) {
 366                 ret = s->isr;
 367             } else {
 368                 ret = s->irr;
 369             }
 370         } else {
 371             ret = s->imr;
 372         }
 373     }
 374     DPRINTF("read: addr=0x%02" HWADDR_PRIx " val=0x%02x\n", addr, ret);
 375     return ret;
 376 }
 377
 378 int pic_get_output(DeviceState *d)
 379 {
 380     PICCommonState *s = PIC_COMMON(d);
 381
 382     return (pic_get_irq(s) >= 0);
 383 }
 384
 385 static void elcr_ioport_write(void *opaque, hwaddr addr,
 386                               uint64_t val, unsigned size)
 387 {
 388     PICCommonState *s = opaque;
 389     s->elcr = val & s->elcr_mask;
 390 }
 391
 392 static uint64_t elcr_ioport_read(void *opaque, hwaddr addr,
 393                                  unsigned size)
 394 {
 395     PICCommonState *s = opaque;
 396     return s->elcr;
 397 }
 398
 399 static const MemoryRegionOps pic_base_ioport_ops = {
 400     .read = pic_ioport_read,
 401     .write = pic_ioport_write,
 402     .impl = {
 403         .min_access_size = 1,
 404         .max_access_size = 1,
 405     },
 406 };
 407
 408 static const MemoryRegionOps pic_elcr_ioport_ops = {
 409     .read = elcr_ioport_read,
 410     .write = elcr_ioport_write,
 411     .impl = {
 412         .min_access_size = 1,
 413         .max_access_size = 1,
 414     },
 415 };
 416
 417 static void pic_realize(DeviceState *dev, Error **errp)
 418 {
 419     PICCommonState *s = PIC_COMMON(dev);
 420     PICClass *pc = PIC_GET_CLASS(dev);
 421
 422     memory_region_init_io(&s->base_io, OBJECT(s), &pic_base_ioport_ops, s,
 423                           "pic", 2);
 424     memory_region_init_io(&s->elcr_io, OBJECT(s), &pic_elcr_ioport_ops, s,
 425                           "elcr", 1);
 426
 427     qdev_init_gpio_out(dev, s->int_out, ARRAY_SIZE(s->int_out));
 428     qdev_init_gpio_in(dev, pic_set_irq, 8);
 429
 430     pc->parent_realize(dev, errp);
 431 }
 432
 433 void hmp_info_pic(Monitor *mon, const QDict *qdict)
 434 {
 435     int i;
 436     PICCommonState *s;
 437
 438     if (!isa_pic) {
 439         return;
 440     }
 441     for (i = 0; i < 2; i++) {
 442         s = i == 0 ? PIC_COMMON(isa_pic) : slave_pic;
 443         monitor_printf(mon, "pic%d: irr=%02x imr=%02x isr=%02x hprio=%d "
 444                        "irq_base=%02x rr_sel=%d elcr=%02x fnm=%d\n",
 445                        i, s->irr, s->imr, s->isr, s->priority_add,
 446                        s->irq_base, s->read_reg_select, s->elcr,
 447                        s->special_fully_nested_mode);
 448     }
 449 }
 450
 451 void hmp_info_irq(Monitor *mon, const QDict *qdict)
 452 {
 453 #ifndef DEBUG_IRQ_COUNT
 454     monitor_printf(mon, "irq statistic code not compiled.\n");
 455 #else
 456     int i;
 457     int64_t count;
 458
 459     monitor_printf(mon, "IRQ statistics:\n");
 460     for (i = 0; i < 16; i++) {
 461         count = irq_count[i];
 462         if (count > 0) {
 463             monitor_printf(mon, "%2d: %" PRId64 "\n", i, count);
 464         }
 465     }
 466 #endif
 467 }
 468
 469 qemu_irq *i8259_init(ISABus *bus, qemu_irq parent_irq)
 470 {
 471     qemu_irq *irq_set;
 472     DeviceState *dev;
 473     ISADevice *isadev;
 474     int i;
 475
 476     irq_set = g_new0(qemu_irq, ISA_NUM_IRQS);
 477
 478     isadev = i8259_init_chip(TYPE_I8259, bus, true);
 479     dev = DEVICE(isadev);
 480
 481     qdev_connect_gpio_out(dev, 0, parent_irq);
 482     for (i = 0 ; i < 8; i++) {
 483         irq_set[i] = qdev_get_gpio_in(dev, i);
 484     }
 485
 486     isa_pic = dev;
 487
 488     isadev = i8259_init_chip(TYPE_I8259, bus, false);
 489     dev = DEVICE(isadev);
 490
 491     qdev_connect_gpio_out(dev, 0, irq_set[2]);
 492     for (i = 0 ; i < 8; i++) {
 493         irq_set[i + 8] = qdev_get_gpio_in(dev, i);
 494     }
 495
 496     slave_pic = PIC_COMMON(dev);
 497
 498     return irq_set;
 499 }
 500
 501 static void i8259_class_init(ObjectClass *klass, void *data)
 502 {
 503     PICClass *k = PIC_CLASS(klass);
 504     DeviceClass *dc = DEVICE_CLASS(klass);
 505
 506     k->parent_realize = dc->realize;
 507     dc->realize = pic_realize;
 508     dc->reset = pic_reset;
 509 }
 510
 511 static const TypeInfo i8259_info = {
 512     .name       = TYPE_I8259,
 513     .instance_size = sizeof(PICCommonState),
 514     .parent     = TYPE_PIC_COMMON,
 515     .class_init = i8259_class_init,
 516     .class_size = sizeof(PICClass),
 517 };
 518
 519 static void pic_register_types(void)
 520 {
 521     type_register_static(&i8259_info);
 522 }
 523
 524 type_init(pic_register_types)