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