2 * High Precisition Event Timer emulation
4 * Copyright (c) 2007 Alexander Graf
5 * Copyright (c) 2008 IBM Corporation
7 * Authors: Beth Kon <bkon@us.ibm.com>
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 static uint32_t hpet_in_legacy_mode(HPETState
*s
)
79 return s
->config
& HPET_CFG_LEGACY
;
82 static uint32_t timer_int_route(struct HPETTimer
*timer
)
84 return (timer
->config
& HPET_TN_INT_ROUTE_MASK
) >> HPET_TN_INT_ROUTE_SHIFT
;
87 static uint32_t timer_fsb_route(HPETTimer
*t
)
89 return t
->config
& HPET_TN_FSB_ENABLE
;
92 static uint32_t hpet_enabled(HPETState
*s
)
94 return s
->config
& HPET_CFG_ENABLE
;
97 static uint32_t timer_is_periodic(HPETTimer
*t
)
99 return t
->config
& HPET_TN_PERIODIC
;
102 static uint32_t timer_enabled(HPETTimer
*t
)
104 return t
->config
& HPET_TN_ENABLE
;
107 static uint32_t hpet_time_after(uint64_t a
, uint64_t b
)
109 return ((int32_t)(b
) - (int32_t)(a
) < 0);
112 static uint32_t hpet_time_after64(uint64_t a
, uint64_t b
)
114 return ((int64_t)(b
) - (int64_t)(a
) < 0);
117 static uint64_t ticks_to_ns(uint64_t value
)
119 return (muldiv64(value
, HPET_CLK_PERIOD
, FS_PER_NS
));
122 static uint64_t ns_to_ticks(uint64_t value
)
124 return (muldiv64(value
, FS_PER_NS
, HPET_CLK_PERIOD
));
127 static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old
, uint64_t mask
)
134 static int activating_bit(uint64_t old
, uint64_t new, uint64_t mask
)
136 return (!(old
& mask
) && (new & mask
));
139 static int deactivating_bit(uint64_t old
, uint64_t new, uint64_t mask
)
141 return ((old
& mask
) && !(new & mask
));
144 static uint64_t hpet_get_ticks(HPETState
*s
)
146 return ns_to_ticks(qemu_get_clock_ns(vm_clock
) + s
->hpet_offset
);
150 * calculate diff between comparator value and current ticks
152 static inline uint64_t hpet_calculate_diff(HPETTimer
*t
, uint64_t current
)
155 if (t
->config
& HPET_TN_32BIT
) {
158 cmp
= (uint32_t)t
->cmp
;
159 diff
= cmp
- (uint32_t)current
;
160 diff
= (int32_t)diff
> 0 ? diff
: (uint32_t)0;
161 return (uint64_t)diff
;
166 diff
= cmp
- current
;
167 diff
= (int64_t)diff
> 0 ? diff
: (uint64_t)0;
172 static void update_irq(struct HPETTimer
*timer
, int set
)
178 if (timer
->tn
<= 1 && hpet_in_legacy_mode(timer
->state
)) {
179 /* if LegacyReplacementRoute bit is set, HPET specification requires
180 * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
181 * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.
183 route
= (timer
->tn
== 0) ? 0 : RTC_ISA_IRQ
;
185 route
= timer_int_route(timer
);
188 mask
= 1 << timer
->tn
;
189 if (!set
|| !timer_enabled(timer
) || !hpet_enabled(timer
->state
)) {
191 if (!timer_fsb_route(timer
)) {
192 qemu_irq_lower(s
->irqs
[route
]);
194 } else if (timer_fsb_route(timer
)) {
195 stl_le_phys(timer
->fsb
>> 32, timer
->fsb
& 0xffffffff);
196 } else if (timer
->config
& HPET_TN_TYPE_LEVEL
) {
198 qemu_irq_raise(s
->irqs
[route
]);
201 qemu_irq_pulse(s
->irqs
[route
]);
205 static void hpet_pre_save(void *opaque
)
207 HPETState
*s
= opaque
;
209 /* save current counter value */
210 s
->hpet_counter
= hpet_get_ticks(s
);
213 static int hpet_pre_load(void *opaque
)
215 HPETState
*s
= opaque
;
217 /* version 1 only supports 3, later versions will load the actual value */
218 s
->num_timers
= HPET_MIN_TIMERS
;
222 static int hpet_post_load(void *opaque
, int version_id
)
224 HPETState
*s
= opaque
;
226 /* Recalculate the offset between the main counter and guest time */
227 s
->hpet_offset
= ticks_to_ns(s
->hpet_counter
) - qemu_get_clock_ns(vm_clock
);
229 /* Push number of timers into capability returned via HPET_ID */
230 s
->capability
&= ~HPET_ID_NUM_TIM_MASK
;
231 s
->capability
|= (s
->num_timers
- 1) << HPET_ID_NUM_TIM_SHIFT
;
232 hpet_cfg
.hpet
[s
->hpet_id
].event_timer_block_id
= (uint32_t)s
->capability
;
234 /* Derive HPET_MSI_SUPPORT from the capability of the first timer. */
235 s
->flags
&= ~(1 << HPET_MSI_SUPPORT
);
236 if (s
->timer
[0].config
& HPET_TN_FSB_CAP
) {
237 s
->flags
|= 1 << HPET_MSI_SUPPORT
;
242 static const VMStateDescription vmstate_hpet_timer
= {
243 .name
= "hpet_timer",
245 .minimum_version_id
= 1,
246 .minimum_version_id_old
= 1,
247 .fields
= (VMStateField
[]) {
248 VMSTATE_UINT8(tn
, HPETTimer
),
249 VMSTATE_UINT64(config
, HPETTimer
),
250 VMSTATE_UINT64(cmp
, HPETTimer
),
251 VMSTATE_UINT64(fsb
, HPETTimer
),
252 VMSTATE_UINT64(period
, HPETTimer
),
253 VMSTATE_UINT8(wrap_flag
, HPETTimer
),
254 VMSTATE_TIMER(qemu_timer
, HPETTimer
),
255 VMSTATE_END_OF_LIST()
259 static const VMStateDescription vmstate_hpet
= {
262 .minimum_version_id
= 1,
263 .minimum_version_id_old
= 1,
264 .pre_save
= hpet_pre_save
,
265 .pre_load
= hpet_pre_load
,
266 .post_load
= hpet_post_load
,
267 .fields
= (VMStateField
[]) {
268 VMSTATE_UINT64(config
, HPETState
),
269 VMSTATE_UINT64(isr
, HPETState
),
270 VMSTATE_UINT64(hpet_counter
, HPETState
),
271 VMSTATE_UINT8_V(num_timers
, HPETState
, 2),
272 VMSTATE_STRUCT_VARRAY_UINT8(timer
, HPETState
, num_timers
, 0,
273 vmstate_hpet_timer
, HPETTimer
),
274 VMSTATE_END_OF_LIST()
279 * timer expiration callback
281 static void hpet_timer(void *opaque
)
283 HPETTimer
*t
= opaque
;
286 uint64_t period
= t
->period
;
287 uint64_t cur_tick
= hpet_get_ticks(t
->state
);
289 if (timer_is_periodic(t
) && period
!= 0) {
290 if (t
->config
& HPET_TN_32BIT
) {
291 while (hpet_time_after(cur_tick
, t
->cmp
)) {
292 t
->cmp
= (uint32_t)(t
->cmp
+ t
->period
);
295 while (hpet_time_after64(cur_tick
, t
->cmp
)) {
299 diff
= hpet_calculate_diff(t
, cur_tick
);
300 qemu_mod_timer(t
->qemu_timer
,
301 qemu_get_clock_ns(vm_clock
) + (int64_t)ticks_to_ns(diff
));
302 } else if (t
->config
& HPET_TN_32BIT
&& !timer_is_periodic(t
)) {
304 diff
= hpet_calculate_diff(t
, cur_tick
);
305 qemu_mod_timer(t
->qemu_timer
, qemu_get_clock_ns(vm_clock
) +
306 (int64_t)ticks_to_ns(diff
));
313 static void hpet_set_timer(HPETTimer
*t
)
316 uint32_t wrap_diff
; /* how many ticks until we wrap? */
317 uint64_t cur_tick
= hpet_get_ticks(t
->state
);
319 /* whenever new timer is being set up, make sure wrap_flag is 0 */
321 diff
= hpet_calculate_diff(t
, cur_tick
);
323 /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
324 * counter wraps in addition to an interrupt with comparator match.
326 if (t
->config
& HPET_TN_32BIT
&& !timer_is_periodic(t
)) {
327 wrap_diff
= 0xffffffff - (uint32_t)cur_tick
;
328 if (wrap_diff
< (uint32_t)diff
) {
333 qemu_mod_timer(t
->qemu_timer
,
334 qemu_get_clock_ns(vm_clock
) + (int64_t)ticks_to_ns(diff
));
337 static void hpet_del_timer(HPETTimer
*t
)
339 qemu_del_timer(t
->qemu_timer
);
344 static uint32_t hpet_ram_readb(void *opaque
, target_phys_addr_t addr
)
346 printf("qemu: hpet_read b at %" PRIx64
"\n", addr
);
350 static uint32_t hpet_ram_readw(void *opaque
, target_phys_addr_t addr
)
352 printf("qemu: hpet_read w at %" PRIx64
"\n", addr
);
357 static uint32_t hpet_ram_readl(void *opaque
, target_phys_addr_t addr
)
359 HPETState
*s
= opaque
;
360 uint64_t cur_tick
, index
;
362 DPRINTF("qemu: Enter hpet_ram_readl at %" PRIx64
"\n", addr
);
364 /*address range of all TN regs*/
365 if (index
>= 0x100 && index
<= 0x3ff) {
366 uint8_t timer_id
= (addr
- 0x100) / 0x20;
367 HPETTimer
*timer
= &s
->timer
[timer_id
];
369 if (timer_id
> s
->num_timers
) {
370 DPRINTF("qemu: timer id out of range\n");
374 switch ((addr
- 0x100) % 0x20) {
376 return timer
->config
;
377 case HPET_TN_CFG
+ 4: // Interrupt capabilities
378 return timer
->config
>> 32;
379 case HPET_TN_CMP
: // comparator register
381 case HPET_TN_CMP
+ 4:
382 return timer
->cmp
>> 32;
385 case HPET_TN_ROUTE
+ 4:
386 return timer
->fsb
>> 32;
388 DPRINTF("qemu: invalid hpet_ram_readl\n");
394 return s
->capability
;
396 return s
->capability
>> 32;
400 DPRINTF("qemu: invalid HPET_CFG + 4 hpet_ram_readl\n");
403 if (hpet_enabled(s
)) {
404 cur_tick
= hpet_get_ticks(s
);
406 cur_tick
= s
->hpet_counter
;
408 DPRINTF("qemu: reading counter = %" PRIx64
"\n", cur_tick
);
410 case HPET_COUNTER
+ 4:
411 if (hpet_enabled(s
)) {
412 cur_tick
= hpet_get_ticks(s
);
414 cur_tick
= s
->hpet_counter
;
416 DPRINTF("qemu: reading counter + 4 = %" PRIx64
"\n", cur_tick
);
417 return cur_tick
>> 32;
421 DPRINTF("qemu: invalid hpet_ram_readl\n");
429 static void hpet_ram_writeb(void *opaque
, target_phys_addr_t addr
,
432 printf("qemu: invalid hpet_write b at %" PRIx64
" = %#x\n",
436 static void hpet_ram_writew(void *opaque
, target_phys_addr_t addr
,
439 printf("qemu: invalid hpet_write w at %" PRIx64
" = %#x\n",
444 static void hpet_ram_writel(void *opaque
, target_phys_addr_t addr
,
448 HPETState
*s
= opaque
;
449 uint64_t old_val
, new_val
, val
, index
;
451 DPRINTF("qemu: Enter hpet_ram_writel at %" PRIx64
" = %#x\n", addr
, value
);
453 old_val
= hpet_ram_readl(opaque
, addr
);
456 /*address range of all TN regs*/
457 if (index
>= 0x100 && index
<= 0x3ff) {
458 uint8_t timer_id
= (addr
- 0x100) / 0x20;
459 HPETTimer
*timer
= &s
->timer
[timer_id
];
461 DPRINTF("qemu: hpet_ram_writel timer_id = %#x\n", timer_id
);
462 if (timer_id
> s
->num_timers
) {
463 DPRINTF("qemu: timer id out of range\n");
466 switch ((addr
- 0x100) % 0x20) {
468 DPRINTF("qemu: hpet_ram_writel HPET_TN_CFG\n");
469 if (activating_bit(old_val
, new_val
, HPET_TN_FSB_ENABLE
)) {
470 update_irq(timer
, 0);
472 val
= hpet_fixup_reg(new_val
, old_val
, HPET_TN_CFG_WRITE_MASK
);
473 timer
->config
= (timer
->config
& 0xffffffff00000000ULL
) | val
;
474 if (new_val
& HPET_TN_32BIT
) {
475 timer
->cmp
= (uint32_t)timer
->cmp
;
476 timer
->period
= (uint32_t)timer
->period
;
478 if (activating_bit(old_val
, new_val
, HPET_TN_ENABLE
)) {
479 hpet_set_timer(timer
);
480 } else if (deactivating_bit(old_val
, new_val
, HPET_TN_ENABLE
)) {
481 hpet_del_timer(timer
);
484 case HPET_TN_CFG
+ 4: // Interrupt capabilities
485 DPRINTF("qemu: invalid HPET_TN_CFG+4 write\n");
487 case HPET_TN_CMP
: // comparator register
488 DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP\n");
489 if (timer
->config
& HPET_TN_32BIT
) {
490 new_val
= (uint32_t)new_val
;
492 if (!timer_is_periodic(timer
)
493 || (timer
->config
& HPET_TN_SETVAL
)) {
494 timer
->cmp
= (timer
->cmp
& 0xffffffff00000000ULL
) | new_val
;
496 if (timer_is_periodic(timer
)) {
498 * FIXME: Clamp period to reasonable min value?
499 * Clamp period to reasonable max value
501 new_val
&= (timer
->config
& HPET_TN_32BIT
? ~0u : ~0ull) >> 1;
503 (timer
->period
& 0xffffffff00000000ULL
) | new_val
;
505 timer
->config
&= ~HPET_TN_SETVAL
;
506 if (hpet_enabled(s
)) {
507 hpet_set_timer(timer
);
510 case HPET_TN_CMP
+ 4: // comparator register high order
511 DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");
512 if (!timer_is_periodic(timer
)
513 || (timer
->config
& HPET_TN_SETVAL
)) {
514 timer
->cmp
= (timer
->cmp
& 0xffffffffULL
) | new_val
<< 32;
517 * FIXME: Clamp period to reasonable min value?
518 * Clamp period to reasonable max value
520 new_val
&= (timer
->config
& HPET_TN_32BIT
? ~0u : ~0ull) >> 1;
522 (timer
->period
& 0xffffffffULL
) | new_val
<< 32;
524 timer
->config
&= ~HPET_TN_SETVAL
;
525 if (hpet_enabled(s
)) {
526 hpet_set_timer(timer
);
530 timer
->fsb
= (timer
->fsb
& 0xffffffff00000000ULL
) | new_val
;
532 case HPET_TN_ROUTE
+ 4:
533 timer
->fsb
= (new_val
<< 32) | (timer
->fsb
& 0xffffffff);
536 DPRINTF("qemu: invalid hpet_ram_writel\n");
545 val
= hpet_fixup_reg(new_val
, old_val
, HPET_CFG_WRITE_MASK
);
546 s
->config
= (s
->config
& 0xffffffff00000000ULL
) | val
;
547 if (activating_bit(old_val
, new_val
, HPET_CFG_ENABLE
)) {
548 /* Enable main counter and interrupt generation. */
550 ticks_to_ns(s
->hpet_counter
) - qemu_get_clock_ns(vm_clock
);
551 for (i
= 0; i
< s
->num_timers
; i
++) {
552 if ((&s
->timer
[i
])->cmp
!= ~0ULL) {
553 hpet_set_timer(&s
->timer
[i
]);
556 } else if (deactivating_bit(old_val
, new_val
, HPET_CFG_ENABLE
)) {
557 /* Halt main counter and disable interrupt generation. */
558 s
->hpet_counter
= hpet_get_ticks(s
);
559 for (i
= 0; i
< s
->num_timers
; i
++) {
560 hpet_del_timer(&s
->timer
[i
]);
563 /* i8254 and RTC are disabled when HPET is in legacy mode */
564 if (activating_bit(old_val
, new_val
, HPET_CFG_LEGACY
)) {
566 qemu_irq_lower(s
->irqs
[RTC_ISA_IRQ
]);
567 } else if (deactivating_bit(old_val
, new_val
, HPET_CFG_LEGACY
)) {
569 qemu_set_irq(s
->irqs
[RTC_ISA_IRQ
], s
->rtc_irq_level
);
573 DPRINTF("qemu: invalid HPET_CFG+4 write\n");
576 val
= new_val
& s
->isr
;
577 for (i
= 0; i
< s
->num_timers
; i
++) {
578 if (val
& (1 << i
)) {
579 update_irq(&s
->timer
[i
], 0);
584 if (hpet_enabled(s
)) {
585 DPRINTF("qemu: Writing counter while HPET enabled!\n");
588 (s
->hpet_counter
& 0xffffffff00000000ULL
) | value
;
589 DPRINTF("qemu: HPET counter written. ctr = %#x -> %" PRIx64
"\n",
590 value
, s
->hpet_counter
);
592 case HPET_COUNTER
+ 4:
593 if (hpet_enabled(s
)) {
594 DPRINTF("qemu: Writing counter while HPET enabled!\n");
597 (s
->hpet_counter
& 0xffffffffULL
) | (((uint64_t)value
) << 32);
598 DPRINTF("qemu: HPET counter + 4 written. ctr = %#x -> %" PRIx64
"\n",
599 value
, s
->hpet_counter
);
602 DPRINTF("qemu: invalid hpet_ram_writel\n");
608 static CPUReadMemoryFunc
* const hpet_ram_read
[] = {
619 static CPUWriteMemoryFunc
* const hpet_ram_write
[] = {
630 static void hpet_reset(DeviceState
*d
)
632 HPETState
*s
= FROM_SYSBUS(HPETState
, sysbus_from_qdev(d
));
634 static int count
= 0;
636 for (i
= 0; i
< s
->num_timers
; i
++) {
637 HPETTimer
*timer
= &s
->timer
[i
];
639 hpet_del_timer(timer
);
641 timer
->config
= HPET_TN_PERIODIC_CAP
| HPET_TN_SIZE_CAP
;
642 if (s
->flags
& (1 << HPET_MSI_SUPPORT
)) {
643 timer
->config
|= HPET_TN_FSB_CAP
;
645 /* advertise availability of ioapic inti2 */
646 timer
->config
|= 0x00000004ULL
<< 32;
647 timer
->period
= 0ULL;
648 timer
->wrap_flag
= 0;
651 s
->hpet_counter
= 0ULL;
652 s
->hpet_offset
= 0ULL;
655 /* we don't enable pit when hpet_reset is first called (by hpet_init)
656 * because hpet is taking over for pit here. On subsequent invocations,
657 * hpet_reset is called due to system reset. At this point control must
658 * be returned to pit until SW reenables hpet.
662 hpet_cfg
.hpet
[s
->hpet_id
].event_timer_block_id
= (uint32_t)s
->capability
;
663 hpet_cfg
.hpet
[s
->hpet_id
].address
= sysbus_from_qdev(d
)->mmio
[0].addr
;
667 static void hpet_handle_rtc_irq(void *opaque
, int n
, int level
)
669 HPETState
*s
= FROM_SYSBUS(HPETState
, opaque
);
671 s
->rtc_irq_level
= level
;
672 if (!hpet_in_legacy_mode(s
)) {
673 qemu_set_irq(s
->irqs
[RTC_ISA_IRQ
], level
);
677 static int hpet_init(SysBusDevice
*dev
)
679 HPETState
*s
= FROM_SYSBUS(HPETState
, dev
);
683 if (hpet_cfg
.count
== UINT8_MAX
) {
688 if (hpet_cfg
.count
== 8) {
689 fprintf(stderr
, "Only 8 instances of HPET is allowed\n");
693 s
->hpet_id
= hpet_cfg
.count
++;
695 for (i
= 0; i
< HPET_NUM_IRQ_ROUTES
; i
++) {
696 sysbus_init_irq(dev
, &s
->irqs
[i
]);
699 if (s
->num_timers
< HPET_MIN_TIMERS
) {
700 s
->num_timers
= HPET_MIN_TIMERS
;
701 } else if (s
->num_timers
> HPET_MAX_TIMERS
) {
702 s
->num_timers
= HPET_MAX_TIMERS
;
704 for (i
= 0; i
< HPET_MAX_TIMERS
; i
++) {
705 timer
= &s
->timer
[i
];
706 timer
->qemu_timer
= qemu_new_timer_ns(vm_clock
, hpet_timer
, timer
);
711 /* 64-bit main counter; LegacyReplacementRoute. */
712 s
->capability
= 0x8086a001ULL
;
713 s
->capability
|= (s
->num_timers
- 1) << HPET_ID_NUM_TIM_SHIFT
;
714 s
->capability
|= ((HPET_CLK_PERIOD
) << 32);
716 qdev_init_gpio_in(&dev
->qdev
, hpet_handle_rtc_irq
, 1);
719 iomemtype
= cpu_register_io_memory(hpet_ram_read
,
721 DEVICE_NATIVE_ENDIAN
);
722 sysbus_init_mmio(dev
, 0x400, iomemtype
);
726 static SysBusDeviceInfo hpet_device_info
= {
728 .qdev
.size
= sizeof(HPETState
),
730 .qdev
.vmsd
= &vmstate_hpet
,
731 .qdev
.reset
= hpet_reset
,
733 .qdev
.props
= (Property
[]) {
734 DEFINE_PROP_UINT8("timers", HPETState
, num_timers
, HPET_MIN_TIMERS
),
735 DEFINE_PROP_BIT("msi", HPETState
, flags
, HPET_MSI_SUPPORT
, false),
736 DEFINE_PROP_END_OF_LIST(),
740 static void hpet_register_device(void)
742 sysbus_register_withprop(&hpet_device_info
);
745 device_init(hpet_register_device
)