hw/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.h"
  25 #include "pc.h"
  26 #include "isa.h"
  27 #include "monitor.h"
  28 #include "qemu-timer.h"
  29
  30 /* debug PIC */
  31 //#define DEBUG_PIC
  32
  33 #ifdef DEBUG_PIC
  34 #define DPRINTF(fmt, ...)                                       \
  35     do { printf("pic: " fmt , ## __VA_ARGS__); } while (0)
  36 #else
  37 #define DPRINTF(fmt, ...)
  38 #endif
  39
  40 //#define DEBUG_IRQ_LATENCY
  41 //#define DEBUG_IRQ_COUNT
  42
  43 typedef struct PicState {
  44     uint8_t last_irr; /* edge detection */
  45     uint8_t irr; /* interrupt request register */
  46     uint8_t imr; /* interrupt mask register */
  47     uint8_t isr; /* interrupt service register */
  48     uint8_t priority_add; /* highest irq priority */
  49     uint8_t irq_base;
  50     uint8_t read_reg_select;
  51     uint8_t poll;
  52     uint8_t special_mask;
  53     uint8_t init_state;
  54     uint8_t auto_eoi;
  55     uint8_t rotate_on_auto_eoi;
  56     uint8_t special_fully_nested_mode;
  57     uint8_t init4; /* true if 4 byte init */
  58     uint8_t single_mode; /* true if slave pic is not initialized */
  59     uint8_t elcr; /* PIIX edge/trigger selection*/
  60     uint8_t elcr_mask;
  61     PicState2 *pics_state;
  62     MemoryRegion base_io;
  63     MemoryRegion elcr_io;
  64 } PicState;
  65
  66 struct PicState2 {
  67     /* 0 is master pic, 1 is slave pic */
  68     /* XXX: better separation between the two pics */
  69     PicState pics[2];
  70     qemu_irq parent_irq;
  71     void *irq_request_opaque;
  72 };
  73
  74 #if defined(DEBUG_PIC) || defined (DEBUG_IRQ_COUNT)
  75 static int irq_level[16];
  76 #endif
  77 #ifdef DEBUG_IRQ_COUNT
  78 static uint64_t irq_count[16];
  79 #endif
  80 PicState2 *isa_pic;
  81
  82 /* set irq level. If an edge is detected, then the IRR is set to 1 */
  83 static inline void pic_set_irq1(PicState *s, int irq, int level)
  84 {
  85     int mask;
  86     mask = 1 << irq;
  87     if (s->elcr & mask) {
  88         /* level triggered */
  89         if (level) {
  90             s->irr |= mask;
  91             s->last_irr |= mask;
  92         } else {
  93             s->irr &= ~mask;
  94             s->last_irr &= ~mask;
  95         }
  96     } else {
  97         /* edge triggered */
  98         if (level) {
  99             if ((s->last_irr & mask) == 0)
 100                 s->irr |= mask;
 101             s->last_irr |= mask;
 102         } else {
 103             s->last_irr &= ~mask;
 104         }
 105     }
 106 }
 107
 108 /* return the highest priority found in mask (highest = smallest
 109    number). Return 8 if no irq */
 110 static inline int get_priority(PicState *s, int mask)
 111 {
 112     int priority;
 113     if (mask == 0)
 114         return 8;
 115     priority = 0;
 116     while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
 117         priority++;
 118     return priority;
 119 }
 120
 121 /* return the pic wanted interrupt. return -1 if none */
 122 static int pic_get_irq(PicState *s)
 123 {
 124     int mask, cur_priority, priority;
 125
 126     mask = s->irr & ~s->imr;
 127     priority = get_priority(s, mask);
 128     if (priority == 8)
 129         return -1;
 130     /* compute current priority. If special fully nested mode on the
 131        master, the IRQ coming from the slave is not taken into account
 132        for the priority computation. */
 133     mask = s->isr;
 134     if (s->special_mask)
 135         mask &= ~s->imr;
 136     if (s->special_fully_nested_mode && s == &s->pics_state->pics[0])
 137         mask &= ~(1 << 2);
 138     cur_priority = get_priority(s, mask);
 139     if (priority < cur_priority) {
 140         /* higher priority found: an irq should be generated */
 141         return (priority + s->priority_add) & 7;
 142     } else {
 143         return -1;
 144     }
 145 }
 146
 147 /* raise irq to CPU if necessary. must be called every time the active
 148    irq may change */
 149 /* XXX: should not export it, but it is needed for an APIC kludge */
 150 void pic_update_irq(PicState2 *s)
 151 {
 152     int irq2, irq;
 153
 154     /* first look at slave pic */
 155     irq2 = pic_get_irq(&s->pics[1]);
 156     if (irq2 >= 0) {
 157         /* if irq request by slave pic, signal master PIC */
 158         pic_set_irq1(&s->pics[0], 2, 1);
 159         pic_set_irq1(&s->pics[0], 2, 0);
 160     }
 161     /* look at requested irq */
 162     irq = pic_get_irq(&s->pics[0]);
 163     if (irq >= 0) {
 164 #if defined(DEBUG_PIC)
 165         {
 166             int i;
 167             for(i = 0; i < 2; i++) {
 168                 printf("pic%d: imr=%x irr=%x padd=%d\n",
 169                        i, s->pics[i].imr, s->pics[i].irr,
 170                        s->pics[i].priority_add);
 171
 172             }
 173         }
 174         printf("pic: cpu_interrupt\n");
 175 #endif
 176         qemu_irq_raise(s->parent_irq);
 177     }
 178
 179 /* all targets should do this rather than acking the IRQ in the cpu */
 180 #if defined(TARGET_MIPS) || defined(TARGET_PPC) || defined(TARGET_ALPHA)
 181     else {
 182         qemu_irq_lower(s->parent_irq);
 183     }
 184 #endif
 185 }
 186
 187 #ifdef DEBUG_IRQ_LATENCY
 188 int64_t irq_time[16];
 189 #endif
 190
 191 static void i8259_set_irq(void *opaque, int irq, int level)
 192 {
 193     PicState2 *s = opaque;
 194
 195 #if defined(DEBUG_PIC) || defined(DEBUG_IRQ_COUNT)
 196     if (level != irq_level[irq]) {
 197         DPRINTF("i8259_set_irq: irq=%d level=%d\n", irq, level);
 198         irq_level[irq] = level;
 199 #ifdef DEBUG_IRQ_COUNT
 200         if (level == 1)
 201             irq_count[irq]++;
 202 #endif
 203     }
 204 #endif
 205 #ifdef DEBUG_IRQ_LATENCY
 206     if (level) {
 207         irq_time[irq] = qemu_get_clock_ns(vm_clock);
 208     }
 209 #endif
 210     pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
 211     pic_update_irq(s);
 212 }
 213
 214 /* acknowledge interrupt 'irq' */
 215 static inline void pic_intack(PicState *s, int irq)
 216 {
 217     if (s->auto_eoi) {
 218         if (s->rotate_on_auto_eoi)
 219             s->priority_add = (irq + 1) & 7;
 220     } else {
 221         s->isr |= (1 << irq);
 222     }
 223     /* We don't clear a level sensitive interrupt here */
 224     if (!(s->elcr & (1 << irq)))
 225         s->irr &= ~(1 << irq);
 226 }
 227
 228 int pic_read_irq(PicState2 *s)
 229 {
 230     int irq, irq2, intno;
 231
 232     irq = pic_get_irq(&s->pics[0]);
 233     if (irq >= 0) {
 234         pic_intack(&s->pics[0], irq);
 235         if (irq == 2) {
 236             irq2 = pic_get_irq(&s->pics[1]);
 237             if (irq2 >= 0) {
 238                 pic_intack(&s->pics[1], irq2);
 239             } else {
 240                 /* spurious IRQ on slave controller */
 241                 irq2 = 7;
 242             }
 243             intno = s->pics[1].irq_base + irq2;
 244 #if defined(DEBUG_PIC) || defined(DEBUG_IRQ_LATENCY)
 245             irq = irq2 + 8;
 246 #endif
 247         } else {
 248             intno = s->pics[0].irq_base + irq;
 249         }
 250     } else {
 251         /* spurious IRQ on host controller */
 252         irq = 7;
 253         intno = s->pics[0].irq_base + irq;
 254     }
 255     pic_update_irq(s);
 256
 257 #ifdef DEBUG_IRQ_LATENCY
 258     printf("IRQ%d latency=%0.3fus\n",
 259            irq,
 260            (double)(qemu_get_clock_ns(vm_clock) -
 261                     irq_time[irq]) * 1000000.0 / get_ticks_per_sec());
 262 #endif
 263     DPRINTF("pic_interrupt: irq=%d\n", irq);
 264     return intno;
 265 }
 266
 267 static void pic_reset(void *opaque)
 268 {
 269     PicState *s = opaque;
 270
 271     s->last_irr = 0;
 272     s->irr = 0;
 273     s->imr = 0;
 274     s->isr = 0;
 275     s->priority_add = 0;
 276     s->irq_base = 0;
 277     s->read_reg_select = 0;
 278     s->poll = 0;
 279     s->special_mask = 0;
 280     s->init_state = 0;
 281     s->auto_eoi = 0;
 282     s->rotate_on_auto_eoi = 0;
 283     s->special_fully_nested_mode = 0;
 284     s->init4 = 0;
 285     s->single_mode = 0;
 286     /* Note: ELCR is not reset */
 287 }
 288
 289 static void pic_ioport_write(void *opaque, target_phys_addr_t addr64,
 290                              uint64_t val64, unsigned size)
 291 {
 292     PicState *s = opaque;
 293     uint32_t addr = addr64;
 294     uint32_t val = val64;
 295     int priority, cmd, irq;
 296
 297     DPRINTF("write: addr=0x%02x val=0x%02x\n", addr, val);
 298     if (addr == 0) {
 299         if (val & 0x10) {
 300             /* init */
 301             pic_reset(s);
 302             /* deassert a pending interrupt */
 303             qemu_irq_lower(s->pics_state->parent_irq);
 304             s->init_state = 1;
 305             s->init4 = val & 1;
 306             s->single_mode = val & 2;
 307             if (val & 0x08)
 308                 hw_error("level sensitive irq not supported");
 309         } else if (val & 0x08) {
 310             if (val & 0x04)
 311                 s->poll = 1;
 312             if (val & 0x02)
 313                 s->read_reg_select = val & 1;
 314             if (val & 0x40)
 315                 s->special_mask = (val >> 5) & 1;
 316         } else {
 317             cmd = val >> 5;
 318             switch(cmd) {
 319             case 0:
 320             case 4:
 321                 s->rotate_on_auto_eoi = cmd >> 2;
 322                 break;
 323             case 1: /* end of interrupt */
 324             case 5:
 325                 priority = get_priority(s, s->isr);
 326                 if (priority != 8) {
 327                     irq = (priority + s->priority_add) & 7;
 328                     s->isr &= ~(1 << irq);
 329                     if (cmd == 5)
 330                         s->priority_add = (irq + 1) & 7;
 331                     pic_update_irq(s->pics_state);
 332                 }
 333                 break;
 334             case 3:
 335                 irq = val & 7;
 336                 s->isr &= ~(1 << irq);
 337                 pic_update_irq(s->pics_state);
 338                 break;
 339             case 6:
 340                 s->priority_add = (val + 1) & 7;
 341                 pic_update_irq(s->pics_state);
 342                 break;
 343             case 7:
 344                 irq = val & 7;
 345                 s->isr &= ~(1 << irq);
 346                 s->priority_add = (irq + 1) & 7;
 347                 pic_update_irq(s->pics_state);
 348                 break;
 349             default:
 350                 /* no operation */
 351                 break;
 352             }
 353         }
 354     } else {
 355         switch(s->init_state) {
 356         case 0:
 357             /* normal mode */
 358             s->imr = val;
 359             pic_update_irq(s->pics_state);
 360             break;
 361         case 1:
 362             s->irq_base = val & 0xf8;
 363             s->init_state = s->single_mode ? (s->init4 ? 3 : 0) : 2;
 364             break;
 365         case 2:
 366             if (s->init4) {
 367                 s->init_state = 3;
 368             } else {
 369                 s->init_state = 0;
 370             }
 371             break;
 372         case 3:
 373             s->special_fully_nested_mode = (val >> 4) & 1;
 374             s->auto_eoi = (val >> 1) & 1;
 375             s->init_state = 0;
 376             break;
 377         }
 378     }
 379 }
 380
 381 static uint32_t pic_poll_read(PicState *s)
 382 {
 383     int ret;
 384
 385     ret = pic_get_irq(s);
 386     if (ret >= 0) {
 387         bool slave = (s == &isa_pic->pics[1]);
 388
 389         if (slave) {
 390             s->pics_state->pics[0].isr &= ~(1 << 2);
 391             s->pics_state->pics[0].irr &= ~(1 << 2);
 392         }
 393         s->irr &= ~(1 << ret);
 394         s->isr &= ~(1 << ret);
 395         if (slave || ret != 2)
 396             pic_update_irq(s->pics_state);
 397     } else {
 398         ret = 0x07;
 399         pic_update_irq(s->pics_state);
 400     }
 401
 402     return ret;
 403 }
 404
 405 static uint64_t pic_ioport_read(void *opaque, target_phys_addr_t addr1,
 406                                 unsigned size)
 407 {
 408     PicState *s = opaque;
 409     unsigned int addr = addr1;
 410     int ret;
 411
 412     if (s->poll) {
 413         ret = pic_poll_read(s);
 414         s->poll = 0;
 415     } else {
 416         if (addr == 0) {
 417             if (s->read_reg_select)
 418                 ret = s->isr;
 419             else
 420                 ret = s->irr;
 421         } else {
 422             ret = s->imr;
 423         }
 424     }
 425     DPRINTF("read: addr=0x%02x val=0x%02x\n", addr, ret);
 426     return ret;
 427 }
 428
 429 /* memory mapped interrupt status */
 430 /* XXX: may be the same than pic_read_irq() */
 431 uint32_t pic_intack_read(PicState2 *s)
 432 {
 433     int ret;
 434
 435     ret = pic_poll_read(&s->pics[0]);
 436     if (ret == 2)
 437         ret = pic_poll_read(&s->pics[1]) + 8;
 438     /* Prepare for ISR read */
 439     s->pics[0].read_reg_select = 1;
 440
 441     return ret;
 442 }
 443
 444 static void elcr_ioport_write(void *opaque, target_phys_addr_t addr,
 445                               uint64_t val, unsigned size)
 446 {
 447     PicState *s = opaque;
 448     s->elcr = val & s->elcr_mask;
 449 }
 450
 451 static uint64_t elcr_ioport_read(void *opaque, target_phys_addr_t addr,
 452                                  unsigned size)
 453 {
 454     PicState *s = opaque;
 455     return s->elcr;
 456 }
 457
 458 static const VMStateDescription vmstate_pic = {
 459     .name = "i8259",
 460     .version_id = 1,
 461     .minimum_version_id = 1,
 462     .minimum_version_id_old = 1,
 463     .fields      = (VMStateField []) {
 464         VMSTATE_UINT8(last_irr, PicState),
 465         VMSTATE_UINT8(irr, PicState),
 466         VMSTATE_UINT8(imr, PicState),
 467         VMSTATE_UINT8(isr, PicState),
 468         VMSTATE_UINT8(priority_add, PicState),
 469         VMSTATE_UINT8(irq_base, PicState),
 470         VMSTATE_UINT8(read_reg_select, PicState),
 471         VMSTATE_UINT8(poll, PicState),
 472         VMSTATE_UINT8(special_mask, PicState),
 473         VMSTATE_UINT8(init_state, PicState),
 474         VMSTATE_UINT8(auto_eoi, PicState),
 475         VMSTATE_UINT8(rotate_on_auto_eoi, PicState),
 476         VMSTATE_UINT8(special_fully_nested_mode, PicState),
 477         VMSTATE_UINT8(init4, PicState),
 478         VMSTATE_UINT8(single_mode, PicState),
 479         VMSTATE_UINT8(elcr, PicState),
 480         VMSTATE_END_OF_LIST()
 481     }
 482 };
 483
 484 static const MemoryRegionOps pic_base_ioport_ops = {
 485     .read = pic_ioport_read,
 486     .write = pic_ioport_write,
 487     .impl = {
 488         .min_access_size = 1,
 489         .max_access_size = 1,
 490     },
 491 };
 492
 493 static const MemoryRegionOps pic_elcr_ioport_ops = {
 494     .read = elcr_ioport_read,
 495     .write = elcr_ioport_write,
 496     .impl = {
 497         .min_access_size = 1,
 498         .max_access_size = 1,
 499     },
 500 };
 501
 502 /* XXX: add generic master/slave system */
 503 static void pic_init1(int io_addr, int elcr_addr, PicState *s)
 504 {
 505     memory_region_init_io(&s->base_io, &pic_base_ioport_ops, s, "pic", 2);
 506     memory_region_init_io(&s->elcr_io, &pic_elcr_ioport_ops, s, "elcr", 1);
 507
 508     isa_register_ioport(NULL, &s->base_io, io_addr);
 509     if (elcr_addr >= 0) {
 510         isa_register_ioport(NULL, &s->elcr_io, elcr_addr);
 511     }
 512
 513     vmstate_register(NULL, io_addr, &vmstate_pic, s);
 514     qemu_register_reset(pic_reset, s);
 515 }
 516
 517 void pic_info(Monitor *mon)
 518 {
 519     int i;
 520     PicState *s;
 521
 522     if (!isa_pic)
 523         return;
 524
 525     for(i=0;i<2;i++) {
 526         s = &isa_pic->pics[i];
 527         monitor_printf(mon, "pic%d: irr=%02x imr=%02x isr=%02x hprio=%d "
 528                        "irq_base=%02x rr_sel=%d elcr=%02x fnm=%d\n",
 529                        i, s->irr, s->imr, s->isr, s->priority_add,
 530                        s->irq_base, s->read_reg_select, s->elcr,
 531                        s->special_fully_nested_mode);
 532     }
 533 }
 534
 535 void irq_info(Monitor *mon)
 536 {
 537 #ifndef DEBUG_IRQ_COUNT
 538     monitor_printf(mon, "irq statistic code not compiled.\n");
 539 #else
 540     int i;
 541     int64_t count;
 542
 543     monitor_printf(mon, "IRQ statistics:\n");
 544     for (i = 0; i < 16; i++) {
 545         count = irq_count[i];
 546         if (count > 0)
 547             monitor_printf(mon, "%2d: %" PRId64 "\n", i, count);
 548     }
 549 #endif
 550 }
 551
 552 qemu_irq *i8259_init(qemu_irq parent_irq)
 553 {
 554     PicState2 *s;
 555
 556     s = g_malloc0(sizeof(PicState2));
 557     pic_init1(0x20, 0x4d0, &s->pics[0]);
 558     pic_init1(0xa0, 0x4d1, &s->pics[1]);
 559     s->pics[0].elcr_mask = 0xf8;
 560     s->pics[1].elcr_mask = 0xde;
 561     s->parent_irq = parent_irq;
 562     s->pics[0].pics_state = s;
 563     s->pics[1].pics_state = s;
 564     isa_pic = s;
 565     return qemu_allocate_irqs(i8259_set_irq, s, 16);
 566 }