hw/hpet.c

   1 /*
   2  *  High Precisition Event Timer emulation
   3  *
   4  *  Copyright (c) 2007 Alexander Graf
   5  *  Copyright (c) 2008 IBM Corporation
   6  *
   7  *  Authors: Beth Kon <bkon@us.ibm.com>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  21  *
  22  * *****************************************************************
  23  *
  24  * This driver attempts to emulate an HPET device in software.
  25  */
  26
  27 #include "hw.h"
  28 #include "pc.h"
  29 #include "console.h"
  30 #include "qemu-timer.h"
  31 #include "hpet_emul.h"
  32
  33 //#define HPET_DEBUG
  34 #ifdef HPET_DEBUG
  35 #define dprintf printf
  36 #else
  37 #define dprintf(...)
  38 #endif
  39
  40 static HPETState *hpet_statep;
  41
  42 uint32_t hpet_in_legacy_mode(void)
  43 {
  44     if (hpet_statep)
  45         return hpet_statep->config & HPET_CFG_LEGACY;
  46     else
  47         return 0;
  48 }
  49
  50 static uint32_t timer_int_route(struct HPETTimer *timer)
  51 {
  52     uint32_t route;
  53     route = (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;
  54     return route;
  55 }
  56
  57 static uint32_t hpet_enabled(void)
  58 {
  59     return hpet_statep->config & HPET_CFG_ENABLE;
  60 }
  61
  62 static uint32_t timer_is_periodic(HPETTimer *t)
  63 {
  64     return t->config & HPET_TN_PERIODIC;
  65 }
  66
  67 static uint32_t timer_enabled(HPETTimer *t)
  68 {
  69     return t->config & HPET_TN_ENABLE;
  70 }
  71
  72 static uint32_t hpet_time_after(uint64_t a, uint64_t b)
  73 {
  74     return ((int32_t)(b) - (int32_t)(a) < 0);
  75 }
  76
  77 static uint32_t hpet_time_after64(uint64_t a, uint64_t b)
  78 {
  79     return ((int64_t)(b) - (int64_t)(a) < 0);
  80 }
  81
  82 static uint64_t ticks_to_ns(uint64_t value)
  83 {
  84     return (muldiv64(value, HPET_CLK_PERIOD, FS_PER_NS));
  85 }
  86
  87 static uint64_t ns_to_ticks(uint64_t value)
  88 {
  89     return (muldiv64(value, FS_PER_NS, HPET_CLK_PERIOD));
  90 }
  91
  92 static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)
  93 {
  94     new &= mask;
  95     new |= old & ~mask;
  96     return new;
  97 }
  98
  99 static int activating_bit(uint64_t old, uint64_t new, uint64_t mask)
 100 {
 101     return (!(old & mask) && (new & mask));
 102 }
 103
 104 static int deactivating_bit(uint64_t old, uint64_t new, uint64_t mask)
 105 {
 106     return ((old & mask) && !(new & mask));
 107 }
 108
 109 static uint64_t hpet_get_ticks(void)
 110 {
 111     uint64_t ticks;
 112     ticks = ns_to_ticks(qemu_get_clock(vm_clock) + hpet_statep->hpet_offset);
 113     return ticks;
 114 }
 115
 116 /*
 117  * calculate diff between comparator value and current ticks
 118  */
 119 static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
 120 {
 121
 122     if (t->config & HPET_TN_32BIT) {
 123         uint32_t diff, cmp;
 124         cmp = (uint32_t)t->cmp;
 125         diff = cmp - (uint32_t)current;
 126         diff = (int32_t)diff > 0 ? diff : (uint32_t)0;
 127         return (uint64_t)diff;
 128     } else {
 129         uint64_t diff, cmp;
 130         cmp = t->cmp;
 131         diff = cmp - current;
 132         diff = (int64_t)diff > 0 ? diff : (uint64_t)0;
 133         return diff;
 134     }
 135 }
 136
 137 static void update_irq(struct HPETTimer *timer)
 138 {
 139     qemu_irq irq;
 140     int route;
 141
 142     if (timer->tn <= 1 && hpet_in_legacy_mode()) {
 143         /* if LegacyReplacementRoute bit is set, HPET specification requires
 144          * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
 145          * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.
 146          */
 147         if (timer->tn == 0) {
 148             irq=timer->state->irqs[0];
 149         } else
 150             irq=timer->state->irqs[8];
 151     } else {
 152         route=timer_int_route(timer);
 153         irq=timer->state->irqs[route];
 154     }
 155     if (timer_enabled(timer) && hpet_enabled()) {
 156         qemu_irq_pulse(irq);
 157     }
 158 }
 159
 160 static void hpet_save(QEMUFile *f, void *opaque)
 161 {
 162     HPETState *s = opaque;
 163     int i;
 164     qemu_put_be64s(f, &s->config);
 165     qemu_put_be64s(f, &s->isr);
 166     /* save current counter value */
 167     s->hpet_counter = hpet_get_ticks();
 168     qemu_put_be64s(f, &s->hpet_counter);
 169
 170     for (i = 0; i < HPET_NUM_TIMERS; i++) {
 171         qemu_put_8s(f, &s->timer[i].tn);
 172         qemu_put_be64s(f, &s->timer[i].config);
 173         qemu_put_be64s(f, &s->timer[i].cmp);
 174         qemu_put_be64s(f, &s->timer[i].fsb);
 175         qemu_put_be64s(f, &s->timer[i].period);
 176         qemu_put_8s(f, &s->timer[i].wrap_flag);
 177         if (s->timer[i].qemu_timer) {
 178             qemu_put_timer(f, s->timer[i].qemu_timer);
 179         }
 180     }
 181 }
 182
 183 static int hpet_load(QEMUFile *f, void *opaque, int version_id)
 184 {
 185     HPETState *s = opaque;
 186     int i;
 187
 188     if (version_id != 1)
 189         return -EINVAL;
 190
 191     qemu_get_be64s(f, &s->config);
 192     qemu_get_be64s(f, &s->isr);
 193     qemu_get_be64s(f, &s->hpet_counter);
 194     /* Recalculate the offset between the main counter and guest time */
 195     s->hpet_offset = ticks_to_ns(s->hpet_counter) - qemu_get_clock(vm_clock);
 196
 197     for (i = 0; i < HPET_NUM_TIMERS; i++) {
 198         qemu_get_8s(f, &s->timer[i].tn);
 199         qemu_get_be64s(f, &s->timer[i].config);
 200         qemu_get_be64s(f, &s->timer[i].cmp);
 201         qemu_get_be64s(f, &s->timer[i].fsb);
 202         qemu_get_be64s(f, &s->timer[i].period);
 203         qemu_get_8s(f, &s->timer[i].wrap_flag);
 204         if (s->timer[i].qemu_timer) {
 205             qemu_get_timer(f, s->timer[i].qemu_timer);
 206         }
 207     }
 208     return 0;
 209 }
 210
 211 /*
 212  * timer expiration callback
 213  */
 214 static void hpet_timer(void *opaque)
 215 {
 216     HPETTimer *t = (HPETTimer*)opaque;
 217     uint64_t diff;
 218
 219     uint64_t period = t->period;
 220     uint64_t cur_tick = hpet_get_ticks();
 221
 222     if (timer_is_periodic(t) && period != 0) {
 223         if (t->config & HPET_TN_32BIT) {
 224             while (hpet_time_after(cur_tick, t->cmp))
 225                 t->cmp = (uint32_t)(t->cmp + t->period);
 226         } else
 227             while (hpet_time_after64(cur_tick, t->cmp))
 228                 t->cmp += period;
 229
 230         diff = hpet_calculate_diff(t, cur_tick);
 231         qemu_mod_timer(t->qemu_timer, qemu_get_clock(vm_clock)
 232                        + (int64_t)ticks_to_ns(diff));
 233     } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
 234         if (t->wrap_flag) {
 235             diff = hpet_calculate_diff(t, cur_tick);
 236             qemu_mod_timer(t->qemu_timer, qemu_get_clock(vm_clock)
 237                            + (int64_t)ticks_to_ns(diff));
 238             t->wrap_flag = 0;
 239         }
 240     }
 241     update_irq(t);
 242 }
 243
 244 static void hpet_set_timer(HPETTimer *t)
 245 {
 246     uint64_t diff;
 247     uint32_t wrap_diff;  /* how many ticks until we wrap? */
 248     uint64_t cur_tick = hpet_get_ticks();
 249
 250     /* whenever new timer is being set up, make sure wrap_flag is 0 */
 251     t->wrap_flag = 0;
 252     diff = hpet_calculate_diff(t, cur_tick);
 253
 254     /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
 255      * counter wraps in addition to an interrupt with comparator match.
 256      */
 257     if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
 258         wrap_diff = 0xffffffff - (uint32_t)cur_tick;
 259         if (wrap_diff < (uint32_t)diff) {
 260             diff = wrap_diff;
 261             t->wrap_flag = 1;
 262         }
 263     }
 264     qemu_mod_timer(t->qemu_timer, qemu_get_clock(vm_clock)
 265                    + (int64_t)ticks_to_ns(diff));
 266 }
 267
 268 static void hpet_del_timer(HPETTimer *t)
 269 {
 270     qemu_del_timer(t->qemu_timer);
 271 }
 272
 273 #ifdef HPET_DEBUG
 274 static uint32_t hpet_ram_readb(void *opaque, target_phys_addr_t addr)
 275 {
 276     printf("qemu: hpet_read b at %" PRIx64 "\n", addr);
 277     return 0;
 278 }
 279
 280 static uint32_t hpet_ram_readw(void *opaque, target_phys_addr_t addr)
 281 {
 282     printf("qemu: hpet_read w at %" PRIx64 "\n", addr);
 283     return 0;
 284 }
 285 #endif
 286
 287 static uint32_t hpet_ram_readl(void *opaque, target_phys_addr_t addr)
 288 {
 289     HPETState *s = (HPETState *)opaque;
 290     uint64_t cur_tick, index;
 291
 292     dprintf("qemu: Enter hpet_ram_readl at %" PRIx64 "\n", addr);
 293     index = addr;
 294     /*address range of all TN regs*/
 295     if (index >= 0x100 && index <= 0x3ff) {
 296         uint8_t timer_id = (addr - 0x100) / 0x20;
 297         if (timer_id > HPET_NUM_TIMERS - 1) {
 298             printf("qemu: timer id out of range\n");
 299             return 0;
 300         }
 301         HPETTimer *timer = &s->timer[timer_id];
 302
 303         switch ((addr - 0x100) % 0x20) {
 304             case HPET_TN_CFG:
 305                 return timer->config;
 306             case HPET_TN_CFG + 4: // Interrupt capabilities
 307                 return timer->config >> 32;
 308             case HPET_TN_CMP: // comparator register
 309                 return timer->cmp;
 310             case HPET_TN_CMP + 4:
 311                 return timer->cmp >> 32;
 312             case HPET_TN_ROUTE:
 313                 return timer->fsb >> 32;
 314             default:
 315                 dprintf("qemu: invalid hpet_ram_readl\n");
 316                 break;
 317         }
 318     } else {
 319         switch (index) {
 320             case HPET_ID:
 321                 return s->capability;
 322             case HPET_PERIOD:
 323                 return s->capability >> 32;
 324             case HPET_CFG:
 325                 return s->config;
 326             case HPET_CFG + 4:
 327                 dprintf("qemu: invalid HPET_CFG + 4 hpet_ram_readl \n");
 328                 return 0;
 329             case HPET_COUNTER:
 330                 if (hpet_enabled())
 331                     cur_tick = hpet_get_ticks();
 332                 else
 333                     cur_tick = s->hpet_counter;
 334                 dprintf("qemu: reading counter  = %" PRIx64 "\n", cur_tick);
 335                 return cur_tick;
 336             case HPET_COUNTER + 4:
 337                 if (hpet_enabled())
 338                     cur_tick = hpet_get_ticks();
 339                 else
 340                     cur_tick = s->hpet_counter;
 341                 dprintf("qemu: reading counter + 4  = %" PRIx64 "\n", cur_tick);
 342                 return cur_tick >> 32;
 343             case HPET_STATUS:
 344                 return s->isr;
 345             default:
 346                 dprintf("qemu: invalid hpet_ram_readl\n");
 347                 break;
 348         }
 349     }
 350     return 0;
 351 }
 352
 353 #ifdef HPET_DEBUG
 354 static void hpet_ram_writeb(void *opaque, target_phys_addr_t addr,
 355                             uint32_t value)
 356 {
 357     printf("qemu: invalid hpet_write b at %" PRIx64 " = %#x\n",
 358            addr, value);
 359 }
 360
 361 static void hpet_ram_writew(void *opaque, target_phys_addr_t addr,
 362                             uint32_t value)
 363 {
 364     printf("qemu: invalid hpet_write w at %" PRIx64 " = %#x\n",
 365            addr, value);
 366 }
 367 #endif
 368
 369 static void hpet_ram_writel(void *opaque, target_phys_addr_t addr,
 370                             uint32_t value)
 371 {
 372     int i;
 373     HPETState *s = (HPETState *)opaque;
 374     uint64_t old_val, new_val, val, index;
 375
 376     dprintf("qemu: Enter hpet_ram_writel at %" PRIx64 " = %#x\n", addr, value);
 377     index = addr;
 378     old_val = hpet_ram_readl(opaque, addr);
 379     new_val = value;
 380
 381     /*address range of all TN regs*/
 382     if (index >= 0x100 && index <= 0x3ff) {
 383         uint8_t timer_id = (addr - 0x100) / 0x20;
 384         dprintf("qemu: hpet_ram_writel timer_id = %#x \n", timer_id);
 385         HPETTimer *timer = &s->timer[timer_id];
 386
 387         switch ((addr - 0x100) % 0x20) {
 388             case HPET_TN_CFG:
 389                 dprintf("qemu: hpet_ram_writel HPET_TN_CFG\n");
 390                 val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
 391                 timer->config = (timer->config & 0xffffffff00000000ULL) | val;
 392                 if (new_val & HPET_TN_32BIT) {
 393                     timer->cmp = (uint32_t)timer->cmp;
 394                     timer->period = (uint32_t)timer->period;
 395                 }
 396                 if (new_val & HPET_TIMER_TYPE_LEVEL) {
 397                     printf("qemu: level-triggered hpet not supported\n");
 398                     exit (-1);
 399                 }
 400
 401                 break;
 402             case HPET_TN_CFG + 4: // Interrupt capabilities
 403                 dprintf("qemu: invalid HPET_TN_CFG+4 write\n");
 404                 break;
 405             case HPET_TN_CMP: // comparator register
 406                 dprintf("qemu: hpet_ram_writel HPET_TN_CMP \n");
 407                 if (timer->config & HPET_TN_32BIT)
 408                     new_val = (uint32_t)new_val;
 409                 if (!timer_is_periodic(timer) ||
 410                            (timer->config & HPET_TN_SETVAL))
 411                     timer->cmp = (timer->cmp & 0xffffffff00000000ULL)
 412                                   | new_val;
 413                 if (timer_is_periodic(timer)) {
 414                     /*
 415                      * FIXME: Clamp period to reasonable min value?
 416                      * Clamp period to reasonable max value
 417                      */
 418                     new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
 419                     timer->period = (timer->period & 0xffffffff00000000ULL)
 420                                      | new_val;
 421                 }
 422                 timer->config &= ~HPET_TN_SETVAL;
 423                 if (hpet_enabled())
 424                     hpet_set_timer(timer);
 425                 break;
 426             case HPET_TN_CMP + 4: // comparator register high order
 427                 dprintf("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");
 428                 if (!timer_is_periodic(timer) ||
 429                            (timer->config & HPET_TN_SETVAL))
 430                     timer->cmp = (timer->cmp & 0xffffffffULL)
 431                                   | new_val << 32;
 432                 else {
 433                     /*
 434                      * FIXME: Clamp period to reasonable min value?
 435                      * Clamp period to reasonable max value
 436                      */
 437                     new_val &= (timer->config
 438                                 & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
 439                     timer->period = (timer->period & 0xffffffffULL)
 440                                      | new_val << 32;
 441                 }
 442                 timer->config &= ~HPET_TN_SETVAL;
 443                 if (hpet_enabled())
 444                     hpet_set_timer(timer);
 445                 break;
 446             case HPET_TN_ROUTE + 4:
 447                 dprintf("qemu: hpet_ram_writel HPET_TN_ROUTE + 4\n");
 448                 break;
 449             default:
 450                 dprintf("qemu: invalid hpet_ram_writel\n");
 451                 break;
 452         }
 453         return;
 454     } else {
 455         switch (index) {
 456             case HPET_ID:
 457                 return;
 458             case HPET_CFG:
 459                 val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
 460                 s->config = (s->config & 0xffffffff00000000ULL) | val;
 461                 if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
 462                     /* Enable main counter and interrupt generation. */
 463                     s->hpet_offset = ticks_to_ns(s->hpet_counter)
 464                                      - qemu_get_clock(vm_clock);
 465                     for (i = 0; i < HPET_NUM_TIMERS; i++)
 466                         if ((&s->timer[i])->cmp != ~0ULL)
 467                             hpet_set_timer(&s->timer[i]);
 468                 }
 469                 else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
 470                     /* Halt main counter and disable interrupt generation. */
 471                     s->hpet_counter = hpet_get_ticks();
 472                     for (i = 0; i < HPET_NUM_TIMERS; i++)
 473                         hpet_del_timer(&s->timer[i]);
 474                 }
 475                 /* i8254 and RTC are disabled when HPET is in legacy mode */
 476                 if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
 477                     hpet_pit_disable();
 478                 } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
 479                     hpet_pit_enable();
 480                 }
 481                 break;
 482             case HPET_CFG + 4:
 483                 dprintf("qemu: invalid HPET_CFG+4 write \n");
 484                 break;
 485             case HPET_STATUS:
 486                 /* FIXME: need to handle level-triggered interrupts */
 487                 break;
 488             case HPET_COUNTER:
 489                if (hpet_enabled())
 490                    printf("qemu: Writing counter while HPET enabled!\n");
 491                s->hpet_counter = (s->hpet_counter & 0xffffffff00000000ULL)
 492                                   | value;
 493                dprintf("qemu: HPET counter written. ctr = %#x -> %" PRIx64 "\n",
 494                         value, s->hpet_counter);
 495                break;
 496             case HPET_COUNTER + 4:
 497                if (hpet_enabled())
 498                    printf("qemu: Writing counter while HPET enabled!\n");
 499                s->hpet_counter = (s->hpet_counter & 0xffffffffULL)
 500                                   | (((uint64_t)value) << 32);
 501                dprintf("qemu: HPET counter + 4 written. ctr = %#x -> %" PRIx64 "\n",
 502                         value, s->hpet_counter);
 503                break;
 504             default:
 505                dprintf("qemu: invalid hpet_ram_writel\n");
 506                break;
 507         }
 508     }
 509 }
 510
 511 static CPUReadMemoryFunc *hpet_ram_read[] = {
 512 #ifdef HPET_DEBUG
 513     hpet_ram_readb,
 514     hpet_ram_readw,
 515 #else
 516     NULL,
 517     NULL,
 518 #endif
 519     hpet_ram_readl,
 520 };
 521
 522 static CPUWriteMemoryFunc *hpet_ram_write[] = {
 523 #ifdef HPET_DEBUG
 524     hpet_ram_writeb,
 525     hpet_ram_writew,
 526 #else
 527     NULL,
 528     NULL,
 529 #endif
 530     hpet_ram_writel,
 531 };
 532
 533 static void hpet_reset(void *opaque) {
 534     HPETState *s = opaque;
 535     int i;
 536     static int count = 0;
 537
 538     for (i=0; i<HPET_NUM_TIMERS; i++) {
 539         HPETTimer *timer = &s->timer[i];
 540         hpet_del_timer(timer);
 541         timer->tn = i;
 542         timer->cmp = ~0ULL;
 543         timer->config =  HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;
 544         /* advertise availability of ioapic inti2 */
 545         timer->config |=  0x00000004ULL << 32;
 546         timer->state = s;
 547         timer->period = 0ULL;
 548         timer->wrap_flag = 0;
 549     }
 550
 551     s->hpet_counter = 0ULL;
 552     s->hpet_offset = 0ULL;
 553     /* 64-bit main counter; 3 timers supported; LegacyReplacementRoute. */
 554     s->capability = 0x8086a201ULL;
 555     s->capability |= ((HPET_CLK_PERIOD) << 32);
 556     s->config = 0ULL;
 557     if (count > 0)
 558         /* we don't enable pit when hpet_reset is first called (by hpet_init)
 559          * because hpet is taking over for pit here. On subsequent invocations,
 560          * hpet_reset is called due to system reset. At this point control must
 561          * be returned to pit until SW reenables hpet.
 562          */
 563         hpet_pit_enable();
 564     count = 1;
 565 }
 566
 567
 568 void hpet_init(qemu_irq *irq) {
 569     int i, iomemtype;
 570     HPETState *s;
 571
 572     dprintf ("hpet_init\n");
 573
 574     s = qemu_mallocz(sizeof(HPETState));
 575     hpet_statep = s;
 576     s->irqs = irq;
 577     for (i=0; i<HPET_NUM_TIMERS; i++) {
 578         HPETTimer *timer = &s->timer[i];
 579         timer->qemu_timer = qemu_new_timer(vm_clock, hpet_timer, timer);
 580     }
 581     hpet_reset(s);
 582     register_savevm("hpet", -1, 1, hpet_save, hpet_load, s);
 583     qemu_register_reset(hpet_reset, s);
 584     /* HPET Area */
 585     iomemtype = cpu_register_io_memory(hpet_ram_read,
 586                                        hpet_ram_write, s);
 587     cpu_register_physical_memory(HPET_BASE, 0x400, iomemtype);
 588 }