2 * High Precisition Event Timer emulation
4 * Copyright (c) 2007 Alexander Graf
5 * Copyright (c) 2008 IBM Corporation
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.
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.
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/>.
22 * *****************************************************************
24 * This driver attempts to emulate an HPET device in software.
30 #include "qemu-timer.h"
31 #include "hpet_emul.h"
33 #include "mc146818rtc.h"
37 #define DPRINTF printf
42 #define HPET_MSI_SUPPORT 0
45 typedef struct HPETTimer { /* timers */
46 uint8_t tn; /*timer number*/
47 QEMUTimer *qemu_timer;
48 struct HPETState *state;
49 /* Memory-mapped, software visible timer registers */
50 uint64_t config; /* configuration/cap */
51 uint64_t cmp; /* comparator */
52 uint64_t fsb; /* FSB route */
53 /* Hidden register state */
54 uint64_t period; /* Last value written to comparator */
55 uint8_t wrap_flag; /* timer pop will indicate wrap for one-shot 32-bit
56 * mode. Next pop will be actual timer expiration.
60 typedef struct HPETState {
63 qemu_irq irqs[HPET_NUM_IRQ_ROUTES];
65 uint8_t rtc_irq_level;
67 HPETTimer timer[HPET_MAX_TIMERS];
69 /* Memory-mapped, software visible registers */
70 uint64_t capability; /* capabilities */
71 uint64_t config; /* configuration */
72 uint64_t isr; /* interrupt status reg */
73 uint64_t hpet_counter; /* main counter */
74 uint8_t hpet_id; /* instance id */
77 struct hpet_fw_config hpet_cfg = {.count = UINT8_MAX};
79 static uint32_t hpet_in_legacy_mode(HPETState *s)
81 return s->config & HPET_CFG_LEGACY;
84 static uint32_t timer_int_route(struct HPETTimer *timer)
86 return (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;
89 static uint32_t timer_fsb_route(HPETTimer *t)
91 return t->config & HPET_TN_FSB_ENABLE;
94 static uint32_t hpet_enabled(HPETState *s)
96 return s->config & HPET_CFG_ENABLE;
99 static uint32_t timer_is_periodic(HPETTimer *t)
101 return t->config & HPET_TN_PERIODIC;
104 static uint32_t timer_enabled(HPETTimer *t)
106 return t->config & HPET_TN_ENABLE;
109 static uint32_t hpet_time_after(uint64_t a, uint64_t b)
111 return ((int32_t)(b) - (int32_t)(a) < 0);
114 static uint32_t hpet_time_after64(uint64_t a, uint64_t b)
116 return ((int64_t)(b) - (int64_t)(a) < 0);
119 static uint64_t ticks_to_ns(uint64_t value)
121 return (muldiv64(value, HPET_CLK_PERIOD, FS_PER_NS));
124 static uint64_t ns_to_ticks(uint64_t value)
126 return (muldiv64(value, FS_PER_NS, HPET_CLK_PERIOD));
129 static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)
136 static int activating_bit(uint64_t old, uint64_t new, uint64_t mask)
138 return (!(old & mask) && (new & mask));
141 static int deactivating_bit(uint64_t old, uint64_t new, uint64_t mask)
143 return ((old & mask) && !(new & mask));
146 static uint64_t hpet_get_ticks(HPETState *s)
148 return ns_to_ticks(qemu_get_clock(vm_clock) + s->hpet_offset);
152 * calculate diff between comparator value and current ticks
154 static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
157 if (t->config & HPET_TN_32BIT) {
160 cmp = (uint32_t)t->cmp;
161 diff = cmp - (uint32_t)current;
162 diff = (int32_t)diff > 0 ? diff : (uint32_t)0;
163 return (uint64_t)diff;
168 diff = cmp - current;
169 diff = (int64_t)diff > 0 ? diff : (uint64_t)0;
174 static void update_irq(struct HPETTimer *timer, int set)
180 if (timer->tn <= 1 && hpet_in_legacy_mode(timer->state)) {
181 /* if LegacyReplacementRoute bit is set, HPET specification requires
182 * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
183 * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.
185 route = (timer->tn == 0) ? 0 : RTC_ISA_IRQ;
187 route = timer_int_route(timer);
190 mask = 1 << timer->tn;
191 if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
193 if (!timer_fsb_route(timer)) {
194 qemu_irq_lower(s->irqs[route]);
196 } else if (timer_fsb_route(timer)) {
197 stl_phys(timer->fsb >> 32, timer->fsb & 0xffffffff);
198 } else if (timer->config & HPET_TN_TYPE_LEVEL) {
200 qemu_irq_raise(s->irqs[route]);
203 qemu_irq_pulse(s->irqs[route]);
207 static void hpet_pre_save(void *opaque)
209 HPETState *s = opaque;
211 /* save current counter value */
212 s->hpet_counter = hpet_get_ticks(s);
215 static int hpet_pre_load(void *opaque)
217 HPETState *s = opaque;
219 /* version 1 only supports 3, later versions will load the actual value */
220 s->num_timers = HPET_MIN_TIMERS;
224 static int hpet_post_load(void *opaque, int version_id)
226 HPETState *s = opaque;
228 /* Recalculate the offset between the main counter and guest time */
229 s->hpet_offset = ticks_to_ns(s->hpet_counter) - qemu_get_clock(vm_clock);
231 /* Push number of timers into capability returned via HPET_ID */
232 s->capability &= ~HPET_ID_NUM_TIM_MASK;
233 s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
234 hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
236 /* Derive HPET_MSI_SUPPORT from the capability of the first timer. */
237 s->flags &= ~(1 << HPET_MSI_SUPPORT);
238 if (s->timer[0].config & HPET_TN_FSB_CAP) {
239 s->flags |= 1 << HPET_MSI_SUPPORT;
244 static const VMStateDescription vmstate_hpet_timer = {
245 .name = "hpet_timer",
247 .minimum_version_id = 1,
248 .minimum_version_id_old = 1,
249 .fields = (VMStateField []) {
250 VMSTATE_UINT8(tn, HPETTimer),
251 VMSTATE_UINT64(config, HPETTimer),
252 VMSTATE_UINT64(cmp, HPETTimer),
253 VMSTATE_UINT64(fsb, HPETTimer),
254 VMSTATE_UINT64(period, HPETTimer),
255 VMSTATE_UINT8(wrap_flag, HPETTimer),
256 VMSTATE_TIMER(qemu_timer, HPETTimer),
257 VMSTATE_END_OF_LIST()
261 static const VMStateDescription vmstate_hpet = {
264 .minimum_version_id = 1,
265 .minimum_version_id_old = 1,
266 .pre_save = hpet_pre_save,
267 .pre_load = hpet_pre_load,
268 .post_load = hpet_post_load,
269 .fields = (VMStateField []) {
270 VMSTATE_UINT64(config, HPETState),
271 VMSTATE_UINT64(isr, HPETState),
272 VMSTATE_UINT64(hpet_counter, HPETState),
273 VMSTATE_UINT8_V(num_timers, HPETState, 2),
274 VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0,
275 vmstate_hpet_timer, HPETTimer),
276 VMSTATE_END_OF_LIST()
281 * timer expiration callback
283 static void hpet_timer(void *opaque)
285 HPETTimer *t = opaque;
288 uint64_t period = t->period;
289 uint64_t cur_tick = hpet_get_ticks(t->state);
291 if (timer_is_periodic(t) && period != 0) {
292 if (t->config & HPET_TN_32BIT) {
293 while (hpet_time_after(cur_tick, t->cmp)) {
294 t->cmp = (uint32_t)(t->cmp + t->period);
297 while (hpet_time_after64(cur_tick, t->cmp)) {
301 diff = hpet_calculate_diff(t, cur_tick);
302 qemu_mod_timer(t->qemu_timer,
303 qemu_get_clock(vm_clock) + (int64_t)ticks_to_ns(diff));
304 } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
306 diff = hpet_calculate_diff(t, cur_tick);
307 qemu_mod_timer(t->qemu_timer, qemu_get_clock(vm_clock) +
308 (int64_t)ticks_to_ns(diff));
315 static void hpet_set_timer(HPETTimer *t)
318 uint32_t wrap_diff; /* how many ticks until we wrap? */
319 uint64_t cur_tick = hpet_get_ticks(t->state);
321 /* whenever new timer is being set up, make sure wrap_flag is 0 */
323 diff = hpet_calculate_diff(t, cur_tick);
325 /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
326 * counter wraps in addition to an interrupt with comparator match.
328 if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
329 wrap_diff = 0xffffffff - (uint32_t)cur_tick;
330 if (wrap_diff < (uint32_t)diff) {
335 qemu_mod_timer(t->qemu_timer,
336 qemu_get_clock(vm_clock) + (int64_t)ticks_to_ns(diff));
339 static void hpet_del_timer(HPETTimer *t)
341 qemu_del_timer(t->qemu_timer);
346 static uint32_t hpet_ram_readb(void *opaque, target_phys_addr_t addr)
348 printf("qemu: hpet_read b at %" PRIx64 "\n", addr);
352 static uint32_t hpet_ram_readw(void *opaque, target_phys_addr_t addr)
354 printf("qemu: hpet_read w at %" PRIx64 "\n", addr);
359 static uint32_t hpet_ram_readl(void *opaque, target_phys_addr_t addr)
361 HPETState *s = opaque;
362 uint64_t cur_tick, index;
364 DPRINTF("qemu: Enter hpet_ram_readl at %" PRIx64 "\n", addr);
366 /*address range of all TN regs*/
367 if (index >= 0x100 && index <= 0x3ff) {
368 uint8_t timer_id = (addr - 0x100) / 0x20;
369 HPETTimer *timer = &s->timer[timer_id];
371 if (timer_id > s->num_timers) {
372 DPRINTF("qemu: timer id out of range\n");
376 switch ((addr - 0x100) % 0x20) {
378 return timer->config;
379 case HPET_TN_CFG + 4: // Interrupt capabilities
380 return timer->config >> 32;
381 case HPET_TN_CMP: // comparator register
383 case HPET_TN_CMP + 4:
384 return timer->cmp >> 32;
387 case HPET_TN_ROUTE + 4:
388 return timer->fsb >> 32;
390 DPRINTF("qemu: invalid hpet_ram_readl\n");
396 return s->capability;
398 return s->capability >> 32;
402 DPRINTF("qemu: invalid HPET_CFG + 4 hpet_ram_readl \n");
405 if (hpet_enabled(s)) {
406 cur_tick = hpet_get_ticks(s);
408 cur_tick = s->hpet_counter;
410 DPRINTF("qemu: reading counter = %" PRIx64 "\n", cur_tick);
412 case HPET_COUNTER + 4:
413 if (hpet_enabled(s)) {
414 cur_tick = hpet_get_ticks(s);
416 cur_tick = s->hpet_counter;
418 DPRINTF("qemu: reading counter + 4 = %" PRIx64 "\n", cur_tick);
419 return cur_tick >> 32;
423 DPRINTF("qemu: invalid hpet_ram_readl\n");
431 static void hpet_ram_writeb(void *opaque, target_phys_addr_t addr,
434 printf("qemu: invalid hpet_write b at %" PRIx64 " = %#x\n",
438 static void hpet_ram_writew(void *opaque, target_phys_addr_t addr,
441 printf("qemu: invalid hpet_write w at %" PRIx64 " = %#x\n",
446 static void hpet_ram_writel(void *opaque, target_phys_addr_t addr,
450 HPETState *s = opaque;
451 uint64_t old_val, new_val, val, index;
453 DPRINTF("qemu: Enter hpet_ram_writel at %" PRIx64 " = %#x\n", addr, value);
455 old_val = hpet_ram_readl(opaque, addr);
458 /*address range of all TN regs*/
459 if (index >= 0x100 && index <= 0x3ff) {
460 uint8_t timer_id = (addr - 0x100) / 0x20;
461 HPETTimer *timer = &s->timer[timer_id];
463 DPRINTF("qemu: hpet_ram_writel timer_id = %#x \n", timer_id);
464 if (timer_id > s->num_timers) {
465 DPRINTF("qemu: timer id out of range\n");
468 switch ((addr - 0x100) % 0x20) {
470 DPRINTF("qemu: hpet_ram_writel HPET_TN_CFG\n");
471 if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
472 update_irq(timer, 0);
474 val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
475 timer->config = (timer->config & 0xffffffff00000000ULL) | val;
476 if (new_val & HPET_TN_32BIT) {
477 timer->cmp = (uint32_t)timer->cmp;
478 timer->period = (uint32_t)timer->period;
480 if (activating_bit(old_val, new_val, HPET_TN_ENABLE)) {
481 hpet_set_timer(timer);
482 } else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
483 hpet_del_timer(timer);
486 case HPET_TN_CFG + 4: // Interrupt capabilities
487 DPRINTF("qemu: invalid HPET_TN_CFG+4 write\n");
489 case HPET_TN_CMP: // comparator register
490 DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP \n");
491 if (timer->config & HPET_TN_32BIT) {
492 new_val = (uint32_t)new_val;
494 if (!timer_is_periodic(timer)
495 || (timer->config & HPET_TN_SETVAL)) {
496 timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;
498 if (timer_is_periodic(timer)) {
500 * FIXME: Clamp period to reasonable min value?
501 * Clamp period to reasonable max value
503 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
505 (timer->period & 0xffffffff00000000ULL) | new_val;
507 timer->config &= ~HPET_TN_SETVAL;
508 if (hpet_enabled(s)) {
509 hpet_set_timer(timer);
512 case HPET_TN_CMP + 4: // comparator register high order
513 DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");
514 if (!timer_is_periodic(timer)
515 || (timer->config & HPET_TN_SETVAL)) {
516 timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;
519 * FIXME: Clamp period to reasonable min value?
520 * Clamp period to reasonable max value
522 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
524 (timer->period & 0xffffffffULL) | new_val << 32;
526 timer->config &= ~HPET_TN_SETVAL;
527 if (hpet_enabled(s)) {
528 hpet_set_timer(timer);
532 timer->fsb = (timer->fsb & 0xffffffff00000000ULL) | new_val;
534 case HPET_TN_ROUTE + 4:
535 timer->fsb = (new_val << 32) | (timer->fsb & 0xffffffff);
538 DPRINTF("qemu: invalid hpet_ram_writel\n");
547 val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
548 s->config = (s->config & 0xffffffff00000000ULL) | val;
549 if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
550 /* Enable main counter and interrupt generation. */
552 ticks_to_ns(s->hpet_counter) - qemu_get_clock(vm_clock);
553 for (i = 0; i < s->num_timers; i++) {
554 if ((&s->timer[i])->cmp != ~0ULL) {
555 hpet_set_timer(&s->timer[i]);
558 } else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
559 /* Halt main counter and disable interrupt generation. */
560 s->hpet_counter = hpet_get_ticks(s);
561 for (i = 0; i < s->num_timers; i++) {
562 hpet_del_timer(&s->timer[i]);
565 /* i8254 and RTC are disabled when HPET is in legacy mode */
566 if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
568 qemu_irq_lower(s->irqs[RTC_ISA_IRQ]);
569 } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
571 qemu_set_irq(s->irqs[RTC_ISA_IRQ], s->rtc_irq_level);
575 DPRINTF("qemu: invalid HPET_CFG+4 write \n");
578 val = new_val & s->isr;
579 for (i = 0; i < s->num_timers; i++) {
580 if (val & (1 << i)) {
581 update_irq(&s->timer[i], 0);
586 if (hpet_enabled(s)) {
587 DPRINTF("qemu: Writing counter while HPET enabled!\n");
590 (s->hpet_counter & 0xffffffff00000000ULL) | value;
591 DPRINTF("qemu: HPET counter written. ctr = %#x -> %" PRIx64 "\n",
592 value, s->hpet_counter);
594 case HPET_COUNTER + 4:
595 if (hpet_enabled(s)) {
596 DPRINTF("qemu: Writing counter while HPET enabled!\n");
599 (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);
600 DPRINTF("qemu: HPET counter + 4 written. ctr = %#x -> %" PRIx64 "\n",
601 value, s->hpet_counter);
604 DPRINTF("qemu: invalid hpet_ram_writel\n");
610 static CPUReadMemoryFunc * const hpet_ram_read[] = {
621 static CPUWriteMemoryFunc * const hpet_ram_write[] = {
632 static void hpet_reset(DeviceState *d)
634 HPETState *s = FROM_SYSBUS(HPETState, sysbus_from_qdev(d));
636 static int count = 0;
638 for (i = 0; i < s->num_timers; i++) {
639 HPETTimer *timer = &s->timer[i];
641 hpet_del_timer(timer);
643 timer->config = HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;
644 if (s->flags & (1 << HPET_MSI_SUPPORT)) {
645 timer->config |= HPET_TN_FSB_CAP;
647 /* advertise availability of ioapic inti2 */
648 timer->config |= 0x00000004ULL << 32;
649 timer->period = 0ULL;
650 timer->wrap_flag = 0;
653 s->hpet_counter = 0ULL;
654 s->hpet_offset = 0ULL;
657 /* we don't enable pit when hpet_reset is first called (by hpet_init)
658 * because hpet is taking over for pit here. On subsequent invocations,
659 * hpet_reset is called due to system reset. At this point control must
660 * be returned to pit until SW reenables hpet.
664 hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
665 hpet_cfg.hpet[s->hpet_id].address = sysbus_from_qdev(d)->mmio[0].addr;
669 static void hpet_handle_rtc_irq(void *opaque, int n, int level)
671 HPETState *s = FROM_SYSBUS(HPETState, opaque);
673 s->rtc_irq_level = level;
674 if (!hpet_in_legacy_mode(s)) {
675 qemu_set_irq(s->irqs[RTC_ISA_IRQ], level);
679 static int hpet_init(SysBusDevice *dev)
681 HPETState *s = FROM_SYSBUS(HPETState, dev);
685 if (hpet_cfg.count == UINT8_MAX) {
690 if (hpet_cfg.count == 8) {
691 fprintf(stderr, "Only 8 instances of HPET is allowed\n");
695 s->hpet_id = hpet_cfg.count++;
697 for (i = 0; i < HPET_NUM_IRQ_ROUTES; i++) {
698 sysbus_init_irq(dev, &s->irqs[i]);
701 if (s->num_timers < HPET_MIN_TIMERS) {
702 s->num_timers = HPET_MIN_TIMERS;
703 } else if (s->num_timers > HPET_MAX_TIMERS) {
704 s->num_timers = HPET_MAX_TIMERS;
706 for (i = 0; i < HPET_MAX_TIMERS; i++) {
707 timer = &s->timer[i];
708 timer->qemu_timer = qemu_new_timer(vm_clock, hpet_timer, timer);
713 /* 64-bit main counter; LegacyReplacementRoute. */
714 s->capability = 0x8086a001ULL;
715 s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
716 s->capability |= ((HPET_CLK_PERIOD) << 32);
718 isa_reserve_irq(RTC_ISA_IRQ);
719 qdev_init_gpio_in(&dev->qdev, hpet_handle_rtc_irq, 1);
722 iomemtype = cpu_register_io_memory(hpet_ram_read,
724 DEVICE_NATIVE_ENDIAN);
725 sysbus_init_mmio(dev, 0x400, iomemtype);
729 static SysBusDeviceInfo hpet_device_info = {
731 .qdev.size = sizeof(HPETState),
733 .qdev.vmsd = &vmstate_hpet,
734 .qdev.reset = hpet_reset,
736 .qdev.props = (Property[]) {
737 DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
738 DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
739 DEFINE_PROP_END_OF_LIST(),
743 static void hpet_register_device(void)
745 sysbus_register_withprop(&hpet_device_info);
748 device_init(hpet_register_device)