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
  29 /* debug PIC */
  30 //#define DEBUG_PIC
  31
  32 //#define DEBUG_IRQ_LATENCY
  33 //#define DEBUG_IRQ_COUNT
  34
  35 typedef struct PicState {
  36     uint8_t last_irr; /* edge detection */
  37     uint8_t irr; /* interrupt request register */
  38     uint8_t imr; /* interrupt mask register */
  39     uint8_t isr; /* interrupt service register */
  40     uint8_t priority_add; /* highest irq priority */
  41     uint8_t irq_base;
  42     uint8_t read_reg_select;
  43     uint8_t poll;
  44     uint8_t special_mask;
  45     uint8_t init_state;
  46     uint8_t auto_eoi;
  47     uint8_t rotate_on_auto_eoi;
  48     uint8_t special_fully_nested_mode;
  49     uint8_t init4; /* true if 4 byte init */
  50     uint8_t single_mode; /* true if slave pic is not initialized */
  51     uint8_t elcr; /* PIIX edge/trigger selection*/
  52     uint8_t elcr_mask;
  53     PicState2 *pics_state;
  54 } PicState;
  55
  56 struct PicState2 {
  57     /* 0 is master pic, 1 is slave pic */
  58     /* XXX: better separation between the two pics */
  59     PicState pics[2];
  60     qemu_irq parent_irq;
  61     void *irq_request_opaque;
  62     /* IOAPIC callback support */
  63     SetIRQFunc *alt_irq_func;
  64     void *alt_irq_opaque;
  65 };
  66
  67 #if defined(DEBUG_PIC) || defined (DEBUG_IRQ_COUNT)
  68 static int irq_level[16];
  69 #endif
  70 #ifdef DEBUG_IRQ_COUNT
  71 static uint64_t irq_count[16];
  72 #endif
  73
  74 /* set irq level. If an edge is detected, then the IRR is set to 1 */
  75 static inline void pic_set_irq1(PicState *s, int irq, int level)
  76 {
  77     int mask;
  78     mask = 1 << irq;
  79     if (s->elcr & mask) {
  80         /* level triggered */
  81         if (level) {
  82             s->irr |= mask;
  83             s->last_irr |= mask;
  84         } else {
  85             s->irr &= ~mask;
  86             s->last_irr &= ~mask;
  87         }
  88     } else {
  89         /* edge triggered */
  90         if (level) {
  91             if ((s->last_irr & mask) == 0)
  92                 s->irr |= mask;
  93             s->last_irr |= mask;
  94         } else {
  95             s->last_irr &= ~mask;
  96         }
  97     }
  98 }
  99
 100 /* return the highest priority found in mask (highest = smallest
 101    number). Return 8 if no irq */
 102 static inline int get_priority(PicState *s, int mask)
 103 {
 104     int priority;
 105     if (mask == 0)
 106         return 8;
 107     priority = 0;
 108     while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
 109         priority++;
 110     return priority;
 111 }
 112
 113 /* return the pic wanted interrupt. return -1 if none */
 114 static int pic_get_irq(PicState *s)
 115 {
 116     int mask, cur_priority, priority;
 117
 118     mask = s->irr & ~s->imr;
 119     priority = get_priority(s, mask);
 120     if (priority == 8)
 121         return -1;
 122     /* compute current priority. If special fully nested mode on the
 123        master, the IRQ coming from the slave is not taken into account
 124        for the priority computation. */
 125     mask = s->isr;
 126     if (s->special_mask)
 127         mask &= ~s->imr;
 128     if (s->special_fully_nested_mode && s == &s->pics_state->pics[0])
 129         mask &= ~(1 << 2);
 130     cur_priority = get_priority(s, mask);
 131     if (priority < cur_priority) {
 132         /* higher priority found: an irq should be generated */
 133         return (priority + s->priority_add) & 7;
 134     } else {
 135         return -1;
 136     }
 137 }
 138
 139 /* raise irq to CPU if necessary. must be called every time the active
 140    irq may change */
 141 /* XXX: should not export it, but it is needed for an APIC kludge */
 142 void pic_update_irq(PicState2 *s)
 143 {
 144     int irq2, irq;
 145
 146     /* first look at slave pic */
 147     irq2 = pic_get_irq(&s->pics[1]);
 148     if (irq2 >= 0) {
 149         /* if irq request by slave pic, signal master PIC */
 150         pic_set_irq1(&s->pics[0], 2, 1);
 151         pic_set_irq1(&s->pics[0], 2, 0);
 152     }
 153     /* look at requested irq */
 154     irq = pic_get_irq(&s->pics[0]);
 155     if (irq >= 0) {
 156 #if defined(DEBUG_PIC)
 157         {
 158             int i;
 159             for(i = 0; i < 2; i++) {
 160                 printf("pic%d: imr=%x irr=%x padd=%d\n",
 161                        i, s->pics[i].imr, s->pics[i].irr,
 162                        s->pics[i].priority_add);
 163
 164             }
 165         }
 166         printf("pic: cpu_interrupt\n");
 167 #endif
 168         qemu_irq_raise(s->parent_irq);
 169     }
 170
 171 /* all targets should do this rather than acking the IRQ in the cpu */
 172 #if defined(TARGET_MIPS) || defined(TARGET_PPC) || defined(TARGET_ALPHA)
 173     else {
 174         qemu_irq_lower(s->parent_irq);
 175     }
 176 #endif
 177 }
 178
 179 #ifdef DEBUG_IRQ_LATENCY
 180 int64_t irq_time[16];
 181 #endif
 182
 183 static void i8259_set_irq(void *opaque, int irq, int level)
 184 {
 185     PicState2 *s = opaque;
 186
 187 #if defined(DEBUG_PIC) || defined(DEBUG_IRQ_COUNT)
 188     if (level != irq_level[irq]) {
 189 #if defined(DEBUG_PIC)
 190         printf("i8259_set_irq: irq=%d level=%d\n", irq, level);
 191 #endif
 192         irq_level[irq] = level;
 193 #ifdef DEBUG_IRQ_COUNT
 194         if (level == 1)
 195             irq_count[irq]++;
 196 #endif
 197     }
 198 #endif
 199 #ifdef DEBUG_IRQ_LATENCY
 200     if (level) {
 201         irq_time[irq] = qemu_get_clock(vm_clock);
 202     }
 203 #endif
 204     pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
 205     /* used for IOAPIC irqs */
 206     if (s->alt_irq_func)
 207         s->alt_irq_func(s->alt_irq_opaque, irq, level);
 208     pic_update_irq(s);
 209 }
 210
 211 /* acknowledge interrupt 'irq' */
 212 static inline void pic_intack(PicState *s, int irq)
 213 {
 214     if (s->auto_eoi) {
 215         if (s->rotate_on_auto_eoi)
 216             s->priority_add = (irq + 1) & 7;
 217     } else {
 218         s->isr |= (1 << irq);
 219     }
 220     /* We don't clear a level sensitive interrupt here */
 221     if (!(s->elcr & (1 << irq)))
 222         s->irr &= ~(1 << irq);
 223 }
 224
 225 int pic_read_irq(PicState2 *s)
 226 {
 227     int irq, irq2, intno;
 228
 229     irq = pic_get_irq(&s->pics[0]);
 230     if (irq >= 0) {
 231         pic_intack(&s->pics[0], irq);
 232         if (irq == 2) {
 233             irq2 = pic_get_irq(&s->pics[1]);
 234             if (irq2 >= 0) {
 235                 pic_intack(&s->pics[1], irq2);
 236             } else {
 237                 /* spurious IRQ on slave controller */
 238                 irq2 = 7;
 239             }
 240             intno = s->pics[1].irq_base + irq2;
 241             irq = irq2 + 8;
 242         } else {
 243             intno = s->pics[0].irq_base + irq;
 244         }
 245     } else {
 246         /* spurious IRQ on host controller */
 247         irq = 7;
 248         intno = s->pics[0].irq_base + irq;
 249     }
 250     pic_update_irq(s);
 251
 252 #ifdef DEBUG_IRQ_LATENCY
 253     printf("IRQ%d latency=%0.3fus\n",
 254            irq,
 255            (double)(qemu_get_clock(vm_clock) - irq_time[irq]) * 1000000.0 / ticks_per_sec);
 256 #endif
 257 #if defined(DEBUG_PIC)
 258     printf("pic_interrupt: irq=%d\n", irq);
 259 #endif
 260     return intno;
 261 }
 262
 263 static void pic_reset(void *opaque)
 264 {
 265     PicState *s = opaque;
 266
 267     s->last_irr = 0;
 268     s->irr = 0;
 269     s->imr = 0;
 270     s->isr = 0;
 271     s->priority_add = 0;
 272     s->irq_base = 0;
 273     s->read_reg_select = 0;
 274     s->poll = 0;
 275     s->special_mask = 0;
 276     s->init_state = 0;
 277     s->auto_eoi = 0;
 278     s->rotate_on_auto_eoi = 0;
 279     s->special_fully_nested_mode = 0;
 280     s->init4 = 0;
 281     s->single_mode = 0;
 282     /* Note: ELCR is not reset */
 283 }
 284
 285 static void pic_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 286 {
 287     PicState *s = opaque;
 288     int priority, cmd, irq;
 289
 290 #ifdef DEBUG_PIC
 291     printf("pic_write: addr=0x%02x val=0x%02x\n", addr, val);
 292 #endif
 293     addr &= 1;
 294     if (addr == 0) {
 295         if (val & 0x10) {
 296             /* init */
 297             pic_reset(s);
 298             /* deassert a pending interrupt */
 299             qemu_irq_lower(s->pics_state->parent_irq);
 300             s->init_state = 1;
 301             s->init4 = val & 1;
 302             s->single_mode = val & 2;
 303             if (val & 0x08)
 304                 hw_error("level sensitive irq not supported");
 305         } else if (val & 0x08) {
 306             if (val & 0x04)
 307                 s->poll = 1;
 308             if (val & 0x02)
 309                 s->read_reg_select = val & 1;
 310             if (val & 0x40)
 311                 s->special_mask = (val >> 5) & 1;
 312         } else {
 313             cmd = val >> 5;
 314             switch(cmd) {
 315             case 0:
 316             case 4:
 317                 s->rotate_on_auto_eoi = cmd >> 2;
 318                 break;
 319             case 1: /* end of interrupt */
 320             case 5:
 321                 priority = get_priority(s, s->isr);
 322                 if (priority != 8) {
 323                     irq = (priority + s->priority_add) & 7;
 324                     s->isr &= ~(1 << irq);
 325                     if (cmd == 5)
 326                         s->priority_add = (irq + 1) & 7;
 327                     pic_update_irq(s->pics_state);
 328                 }
 329                 break;
 330             case 3:
 331                 irq = val & 7;
 332                 s->isr &= ~(1 << irq);
 333                 pic_update_irq(s->pics_state);
 334                 break;
 335             case 6:
 336                 s->priority_add = (val + 1) & 7;
 337                 pic_update_irq(s->pics_state);
 338                 break;
 339             case 7:
 340                 irq = val & 7;
 341                 s->isr &= ~(1 << irq);
 342                 s->priority_add = (irq + 1) & 7;
 343                 pic_update_irq(s->pics_state);
 344                 break;
 345             default:
 346                 /* no operation */
 347                 break;
 348             }
 349         }
 350     } else {
 351         switch(s->init_state) {
 352         case 0:
 353             /* normal mode */
 354             s->imr = val;
 355             pic_update_irq(s->pics_state);
 356             break;
 357         case 1:
 358             s->irq_base = val & 0xf8;
 359             s->init_state = s->single_mode ? (s->init4 ? 3 : 0) : 2;
 360             break;
 361         case 2:
 362             if (s->init4) {
 363                 s->init_state = 3;
 364             } else {
 365                 s->init_state = 0;
 366             }
 367             break;
 368         case 3:
 369             s->special_fully_nested_mode = (val >> 4) & 1;
 370             s->auto_eoi = (val >> 1) & 1;
 371             s->init_state = 0;
 372             break;
 373         }
 374     }
 375 }
 376
 377 static uint32_t pic_poll_read (PicState *s, uint32_t addr1)
 378 {
 379     int ret;
 380
 381     ret = pic_get_irq(s);
 382     if (ret >= 0) {
 383         if (addr1 >> 7) {
 384             s->pics_state->pics[0].isr &= ~(1 << 2);
 385             s->pics_state->pics[0].irr &= ~(1 << 2);
 386         }
 387         s->irr &= ~(1 << ret);
 388         s->isr &= ~(1 << ret);
 389         if (addr1 >> 7 || ret != 2)
 390             pic_update_irq(s->pics_state);
 391     } else {
 392         ret = 0x07;
 393         pic_update_irq(s->pics_state);
 394     }
 395
 396     return ret;
 397 }
 398
 399 static uint32_t pic_ioport_read(void *opaque, uint32_t addr1)
 400 {
 401     PicState *s = opaque;
 402     unsigned int addr;
 403     int ret;
 404
 405     addr = addr1;
 406     addr &= 1;
 407     if (s->poll) {
 408         ret = pic_poll_read(s, addr1);
 409         s->poll = 0;
 410     } else {
 411         if (addr == 0) {
 412             if (s->read_reg_select)
 413                 ret = s->isr;
 414             else
 415                 ret = s->irr;
 416         } else {
 417             ret = s->imr;
 418         }
 419     }
 420 #ifdef DEBUG_PIC
 421     printf("pic_read: addr=0x%02x val=0x%02x\n", addr1, ret);
 422 #endif
 423     return ret;
 424 }
 425
 426 /* memory mapped interrupt status */
 427 /* XXX: may be the same than pic_read_irq() */
 428 uint32_t pic_intack_read(PicState2 *s)
 429 {
 430     int ret;
 431
 432     ret = pic_poll_read(&s->pics[0], 0x00);
 433     if (ret == 2)
 434         ret = pic_poll_read(&s->pics[1], 0x80) + 8;
 435     /* Prepare for ISR read */
 436     s->pics[0].read_reg_select = 1;
 437
 438     return ret;
 439 }
 440
 441 static void elcr_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 442 {
 443     PicState *s = opaque;
 444     s->elcr = val & s->elcr_mask;
 445 }
 446
 447 static uint32_t elcr_ioport_read(void *opaque, uint32_t addr1)
 448 {
 449     PicState *s = opaque;
 450     return s->elcr;
 451 }
 452
 453 static void pic_save(QEMUFile *f, void *opaque)
 454 {
 455     PicState *s = opaque;
 456
 457     qemu_put_8s(f, &s->last_irr);
 458     qemu_put_8s(f, &s->irr);
 459     qemu_put_8s(f, &s->imr);
 460     qemu_put_8s(f, &s->isr);
 461     qemu_put_8s(f, &s->priority_add);
 462     qemu_put_8s(f, &s->irq_base);
 463     qemu_put_8s(f, &s->read_reg_select);
 464     qemu_put_8s(f, &s->poll);
 465     qemu_put_8s(f, &s->special_mask);
 466     qemu_put_8s(f, &s->init_state);
 467     qemu_put_8s(f, &s->auto_eoi);
 468     qemu_put_8s(f, &s->rotate_on_auto_eoi);
 469     qemu_put_8s(f, &s->special_fully_nested_mode);
 470     qemu_put_8s(f, &s->init4);
 471     qemu_put_8s(f, &s->single_mode);
 472     qemu_put_8s(f, &s->elcr);
 473 }
 474
 475 static int pic_load(QEMUFile *f, void *opaque, int version_id)
 476 {
 477     PicState *s = opaque;
 478
 479     if (version_id != 1)
 480         return -EINVAL;
 481
 482     qemu_get_8s(f, &s->last_irr);
 483     qemu_get_8s(f, &s->irr);
 484     qemu_get_8s(f, &s->imr);
 485     qemu_get_8s(f, &s->isr);
 486     qemu_get_8s(f, &s->priority_add);
 487     qemu_get_8s(f, &s->irq_base);
 488     qemu_get_8s(f, &s->read_reg_select);
 489     qemu_get_8s(f, &s->poll);
 490     qemu_get_8s(f, &s->special_mask);
 491     qemu_get_8s(f, &s->init_state);
 492     qemu_get_8s(f, &s->auto_eoi);
 493     qemu_get_8s(f, &s->rotate_on_auto_eoi);
 494     qemu_get_8s(f, &s->special_fully_nested_mode);
 495     qemu_get_8s(f, &s->init4);
 496     qemu_get_8s(f, &s->single_mode);
 497     qemu_get_8s(f, &s->elcr);
 498     return 0;
 499 }
 500
 501 /* XXX: add generic master/slave system */
 502 static void pic_init1(int io_addr, int elcr_addr, PicState *s)
 503 {
 504     register_ioport_write(io_addr, 2, 1, pic_ioport_write, s);
 505     register_ioport_read(io_addr, 2, 1, pic_ioport_read, s);
 506     if (elcr_addr >= 0) {
 507         register_ioport_write(elcr_addr, 1, 1, elcr_ioport_write, s);
 508         register_ioport_read(elcr_addr, 1, 1, elcr_ioport_read, s);
 509     }
 510     register_savevm("i8259", io_addr, 1, pic_save, pic_load, s);
 511     qemu_register_reset(pic_reset, s);
 512 }
 513
 514 void pic_info(Monitor *mon)
 515 {
 516     int i;
 517     PicState *s;
 518
 519     if (!isa_pic)
 520         return;
 521
 522     for(i=0;i<2;i++) {
 523         s = &isa_pic->pics[i];
 524         monitor_printf(mon, "pic%d: irr=%02x imr=%02x isr=%02x hprio=%d "
 525                        "irq_base=%02x rr_sel=%d elcr=%02x fnm=%d\n",
 526                        i, s->irr, s->imr, s->isr, s->priority_add,
 527                        s->irq_base, s->read_reg_select, s->elcr,
 528                        s->special_fully_nested_mode);
 529     }
 530 }
 531
 532 void irq_info(Monitor *mon)
 533 {
 534 #ifndef DEBUG_IRQ_COUNT
 535     monitor_printf(mon, "irq statistic code not compiled.\n");
 536 #else
 537     int i;
 538     int64_t count;
 539
 540     monitor_printf(mon, "IRQ statistics:\n");
 541     for (i = 0; i < 16; i++) {
 542         count = irq_count[i];
 543         if (count > 0)
 544             monitor_printf(mon, "%2d: %" PRId64 "\n", i, count);
 545     }
 546 #endif
 547 }
 548
 549 qemu_irq *i8259_init(qemu_irq parent_irq)
 550 {
 551     PicState2 *s;
 552
 553     s = qemu_mallocz(sizeof(PicState2));
 554     pic_init1(0x20, 0x4d0, &s->pics[0]);
 555     pic_init1(0xa0, 0x4d1, &s->pics[1]);
 556     s->pics[0].elcr_mask = 0xf8;
 557     s->pics[1].elcr_mask = 0xde;
 558     s->parent_irq = parent_irq;
 559     s->pics[0].pics_state = s;
 560     s->pics[1].pics_state = s;
 561     isa_pic = s;
 562     return qemu_allocate_irqs(i8259_set_irq, s, 16);
 563 }
 564
 565 void pic_set_alt_irq_func(PicState2 *s, SetIRQFunc *alt_irq_func,
 566                           void *alt_irq_opaque)
 567 {
 568     s->alt_irq_func = alt_irq_func;
 569     s->alt_irq_opaque = alt_irq_opaque;
 570 }