xref: /openbmc/qemu/hw/timer/hpet.c (revision f363d039)
1 /*
2  *  High Precision 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 "qemu/osdep.h"
28 #include "hw/i386/pc.h"
29 #include "hw/irq.h"
30 #include "ui/console.h"
31 #include "qapi/error.h"
32 #include "qemu/error-report.h"
33 #include "qemu/timer.h"
34 #include "hw/timer/hpet.h"
35 #include "hw/sysbus.h"
36 #include "hw/timer/mc146818rtc.h"
37 #include "migration/vmstate.h"
38 #include "hw/timer/i8254.h"
39 
40 //#define HPET_DEBUG
41 #ifdef HPET_DEBUG
42 #define DPRINTF printf
43 #else
44 #define DPRINTF(...)
45 #endif
46 
47 #define HPET_MSI_SUPPORT        0
48 
49 #define HPET(obj) OBJECT_CHECK(HPETState, (obj), TYPE_HPET)
50 
51 struct HPETState;
52 typedef struct HPETTimer {  /* timers */
53     uint8_t tn;             /*timer number*/
54     QEMUTimer *qemu_timer;
55     struct HPETState *state;
56     /* Memory-mapped, software visible timer registers */
57     uint64_t config;        /* configuration/cap */
58     uint64_t cmp;           /* comparator */
59     uint64_t fsb;           /* FSB route */
60     /* Hidden register state */
61     uint64_t period;        /* Last value written to comparator */
62     uint8_t wrap_flag;      /* timer pop will indicate wrap for one-shot 32-bit
63                              * mode. Next pop will be actual timer expiration.
64                              */
65 } HPETTimer;
66 
67 typedef struct HPETState {
68     /*< private >*/
69     SysBusDevice parent_obj;
70     /*< public >*/
71 
72     MemoryRegion iomem;
73     uint64_t hpet_offset;
74     bool hpet_offset_saved;
75     qemu_irq irqs[HPET_NUM_IRQ_ROUTES];
76     uint32_t flags;
77     uint8_t rtc_irq_level;
78     qemu_irq pit_enabled;
79     uint8_t num_timers;
80     uint32_t intcap;
81     HPETTimer timer[HPET_MAX_TIMERS];
82 
83     /* Memory-mapped, software visible registers */
84     uint64_t capability;        /* capabilities */
85     uint64_t config;            /* configuration */
86     uint64_t isr;               /* interrupt status reg */
87     uint64_t hpet_counter;      /* main counter */
88     uint8_t  hpet_id;           /* instance id */
89 } HPETState;
90 
91 static uint32_t hpet_in_legacy_mode(HPETState *s)
92 {
93     return s->config & HPET_CFG_LEGACY;
94 }
95 
96 static uint32_t timer_int_route(struct HPETTimer *timer)
97 {
98     return (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;
99 }
100 
101 static uint32_t timer_fsb_route(HPETTimer *t)
102 {
103     return t->config & HPET_TN_FSB_ENABLE;
104 }
105 
106 static uint32_t hpet_enabled(HPETState *s)
107 {
108     return s->config & HPET_CFG_ENABLE;
109 }
110 
111 static uint32_t timer_is_periodic(HPETTimer *t)
112 {
113     return t->config & HPET_TN_PERIODIC;
114 }
115 
116 static uint32_t timer_enabled(HPETTimer *t)
117 {
118     return t->config & HPET_TN_ENABLE;
119 }
120 
121 static uint32_t hpet_time_after(uint64_t a, uint64_t b)
122 {
123     return ((int32_t)(b - a) < 0);
124 }
125 
126 static uint32_t hpet_time_after64(uint64_t a, uint64_t b)
127 {
128     return ((int64_t)(b - a) < 0);
129 }
130 
131 static uint64_t ticks_to_ns(uint64_t value)
132 {
133     return value * HPET_CLK_PERIOD;
134 }
135 
136 static uint64_t ns_to_ticks(uint64_t value)
137 {
138     return value / HPET_CLK_PERIOD;
139 }
140 
141 static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)
142 {
143     new &= mask;
144     new |= old & ~mask;
145     return new;
146 }
147 
148 static int activating_bit(uint64_t old, uint64_t new, uint64_t mask)
149 {
150     return (!(old & mask) && (new & mask));
151 }
152 
153 static int deactivating_bit(uint64_t old, uint64_t new, uint64_t mask)
154 {
155     return ((old & mask) && !(new & mask));
156 }
157 
158 static uint64_t hpet_get_ticks(HPETState *s)
159 {
160     return ns_to_ticks(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->hpet_offset);
161 }
162 
163 /*
164  * calculate diff between comparator value and current ticks
165  */
166 static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
167 {
168 
169     if (t->config & HPET_TN_32BIT) {
170         uint32_t diff, cmp;
171 
172         cmp = (uint32_t)t->cmp;
173         diff = cmp - (uint32_t)current;
174         diff = (int32_t)diff > 0 ? diff : (uint32_t)1;
175         return (uint64_t)diff;
176     } else {
177         uint64_t diff, cmp;
178 
179         cmp = t->cmp;
180         diff = cmp - current;
181         diff = (int64_t)diff > 0 ? diff : (uint64_t)1;
182         return diff;
183     }
184 }
185 
186 static void update_irq(struct HPETTimer *timer, int set)
187 {
188     uint64_t mask;
189     HPETState *s;
190     int route;
191 
192     if (timer->tn <= 1 && hpet_in_legacy_mode(timer->state)) {
193         /* if LegacyReplacementRoute bit is set, HPET specification requires
194          * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
195          * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.
196          */
197         route = (timer->tn == 0) ? 0 : RTC_ISA_IRQ;
198     } else {
199         route = timer_int_route(timer);
200     }
201     s = timer->state;
202     mask = 1 << timer->tn;
203     if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
204         s->isr &= ~mask;
205         if (!timer_fsb_route(timer)) {
206             qemu_irq_lower(s->irqs[route]);
207         }
208     } else if (timer_fsb_route(timer)) {
209         address_space_stl_le(&address_space_memory, timer->fsb >> 32,
210                              timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
211                              NULL);
212     } else if (timer->config & HPET_TN_TYPE_LEVEL) {
213         s->isr |= mask;
214         qemu_irq_raise(s->irqs[route]);
215     } else {
216         s->isr &= ~mask;
217         qemu_irq_pulse(s->irqs[route]);
218     }
219 }
220 
221 static int hpet_pre_save(void *opaque)
222 {
223     HPETState *s = opaque;
224 
225     /* save current counter value */
226     if (hpet_enabled(s)) {
227         s->hpet_counter = hpet_get_ticks(s);
228     }
229 
230     return 0;
231 }
232 
233 static int hpet_pre_load(void *opaque)
234 {
235     HPETState *s = opaque;
236 
237     /* version 1 only supports 3, later versions will load the actual value */
238     s->num_timers = HPET_MIN_TIMERS;
239     return 0;
240 }
241 
242 static bool hpet_validate_num_timers(void *opaque, int version_id)
243 {
244     HPETState *s = opaque;
245 
246     if (s->num_timers < HPET_MIN_TIMERS) {
247         return false;
248     } else if (s->num_timers > HPET_MAX_TIMERS) {
249         return false;
250     }
251     return true;
252 }
253 
254 static int hpet_post_load(void *opaque, int version_id)
255 {
256     HPETState *s = opaque;
257 
258     /* Recalculate the offset between the main counter and guest time */
259     if (!s->hpet_offset_saved) {
260         s->hpet_offset = ticks_to_ns(s->hpet_counter)
261                         - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
262     }
263 
264     /* Push number of timers into capability returned via HPET_ID */
265     s->capability &= ~HPET_ID_NUM_TIM_MASK;
266     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
267     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
268 
269     /* Derive HPET_MSI_SUPPORT from the capability of the first timer. */
270     s->flags &= ~(1 << HPET_MSI_SUPPORT);
271     if (s->timer[0].config & HPET_TN_FSB_CAP) {
272         s->flags |= 1 << HPET_MSI_SUPPORT;
273     }
274     return 0;
275 }
276 
277 static bool hpet_offset_needed(void *opaque)
278 {
279     HPETState *s = opaque;
280 
281     return hpet_enabled(s) && s->hpet_offset_saved;
282 }
283 
284 static bool hpet_rtc_irq_level_needed(void *opaque)
285 {
286     HPETState *s = opaque;
287 
288     return s->rtc_irq_level != 0;
289 }
290 
291 static const VMStateDescription vmstate_hpet_rtc_irq_level = {
292     .name = "hpet/rtc_irq_level",
293     .version_id = 1,
294     .minimum_version_id = 1,
295     .needed = hpet_rtc_irq_level_needed,
296     .fields = (VMStateField[]) {
297         VMSTATE_UINT8(rtc_irq_level, HPETState),
298         VMSTATE_END_OF_LIST()
299     }
300 };
301 
302 static const VMStateDescription vmstate_hpet_offset = {
303     .name = "hpet/offset",
304     .version_id = 1,
305     .minimum_version_id = 1,
306     .needed = hpet_offset_needed,
307     .fields = (VMStateField[]) {
308         VMSTATE_UINT64(hpet_offset, HPETState),
309         VMSTATE_END_OF_LIST()
310     }
311 };
312 
313 static const VMStateDescription vmstate_hpet_timer = {
314     .name = "hpet_timer",
315     .version_id = 1,
316     .minimum_version_id = 1,
317     .fields = (VMStateField[]) {
318         VMSTATE_UINT8(tn, HPETTimer),
319         VMSTATE_UINT64(config, HPETTimer),
320         VMSTATE_UINT64(cmp, HPETTimer),
321         VMSTATE_UINT64(fsb, HPETTimer),
322         VMSTATE_UINT64(period, HPETTimer),
323         VMSTATE_UINT8(wrap_flag, HPETTimer),
324         VMSTATE_TIMER_PTR(qemu_timer, HPETTimer),
325         VMSTATE_END_OF_LIST()
326     }
327 };
328 
329 static const VMStateDescription vmstate_hpet = {
330     .name = "hpet",
331     .version_id = 2,
332     .minimum_version_id = 1,
333     .pre_save = hpet_pre_save,
334     .pre_load = hpet_pre_load,
335     .post_load = hpet_post_load,
336     .fields = (VMStateField[]) {
337         VMSTATE_UINT64(config, HPETState),
338         VMSTATE_UINT64(isr, HPETState),
339         VMSTATE_UINT64(hpet_counter, HPETState),
340         VMSTATE_UINT8_V(num_timers, HPETState, 2),
341         VMSTATE_VALIDATE("num_timers in range", hpet_validate_num_timers),
342         VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0,
343                                     vmstate_hpet_timer, HPETTimer),
344         VMSTATE_END_OF_LIST()
345     },
346     .subsections = (const VMStateDescription*[]) {
347         &vmstate_hpet_rtc_irq_level,
348         &vmstate_hpet_offset,
349         NULL
350     }
351 };
352 
353 /*
354  * timer expiration callback
355  */
356 static void hpet_timer(void *opaque)
357 {
358     HPETTimer *t = opaque;
359     uint64_t diff;
360 
361     uint64_t period = t->period;
362     uint64_t cur_tick = hpet_get_ticks(t->state);
363 
364     if (timer_is_periodic(t) && period != 0) {
365         if (t->config & HPET_TN_32BIT) {
366             while (hpet_time_after(cur_tick, t->cmp)) {
367                 t->cmp = (uint32_t)(t->cmp + t->period);
368             }
369         } else {
370             while (hpet_time_after64(cur_tick, t->cmp)) {
371                 t->cmp += period;
372             }
373         }
374         diff = hpet_calculate_diff(t, cur_tick);
375         timer_mod(t->qemu_timer,
376                        qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
377     } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
378         if (t->wrap_flag) {
379             diff = hpet_calculate_diff(t, cur_tick);
380             timer_mod(t->qemu_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
381                            (int64_t)ticks_to_ns(diff));
382             t->wrap_flag = 0;
383         }
384     }
385     update_irq(t, 1);
386 }
387 
388 static void hpet_set_timer(HPETTimer *t)
389 {
390     uint64_t diff;
391     uint32_t wrap_diff;  /* how many ticks until we wrap? */
392     uint64_t cur_tick = hpet_get_ticks(t->state);
393 
394     /* whenever new timer is being set up, make sure wrap_flag is 0 */
395     t->wrap_flag = 0;
396     diff = hpet_calculate_diff(t, cur_tick);
397 
398     /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
399      * counter wraps in addition to an interrupt with comparator match.
400      */
401     if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
402         wrap_diff = 0xffffffff - (uint32_t)cur_tick;
403         if (wrap_diff < (uint32_t)diff) {
404             diff = wrap_diff;
405             t->wrap_flag = 1;
406         }
407     }
408     timer_mod(t->qemu_timer,
409                    qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
410 }
411 
412 static void hpet_del_timer(HPETTimer *t)
413 {
414     timer_del(t->qemu_timer);
415     update_irq(t, 0);
416 }
417 
418 #ifdef HPET_DEBUG
419 static uint32_t hpet_ram_readb(void *opaque, hwaddr addr)
420 {
421     printf("qemu: hpet_read b at %" PRIx64 "\n", addr);
422     return 0;
423 }
424 
425 static uint32_t hpet_ram_readw(void *opaque, hwaddr addr)
426 {
427     printf("qemu: hpet_read w at %" PRIx64 "\n", addr);
428     return 0;
429 }
430 #endif
431 
432 static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
433                               unsigned size)
434 {
435     HPETState *s = opaque;
436     uint64_t cur_tick, index;
437 
438     DPRINTF("qemu: Enter hpet_ram_readl at %" PRIx64 "\n", addr);
439     index = addr;
440     /*address range of all TN regs*/
441     if (index >= 0x100 && index <= 0x3ff) {
442         uint8_t timer_id = (addr - 0x100) / 0x20;
443         HPETTimer *timer = &s->timer[timer_id];
444 
445         if (timer_id > s->num_timers) {
446             DPRINTF("qemu: timer id out of range\n");
447             return 0;
448         }
449 
450         switch ((addr - 0x100) % 0x20) {
451         case HPET_TN_CFG:
452             return timer->config;
453         case HPET_TN_CFG + 4: // Interrupt capabilities
454             return timer->config >> 32;
455         case HPET_TN_CMP: // comparator register
456             return timer->cmp;
457         case HPET_TN_CMP + 4:
458             return timer->cmp >> 32;
459         case HPET_TN_ROUTE:
460             return timer->fsb;
461         case HPET_TN_ROUTE + 4:
462             return timer->fsb >> 32;
463         default:
464             DPRINTF("qemu: invalid hpet_ram_readl\n");
465             break;
466         }
467     } else {
468         switch (index) {
469         case HPET_ID:
470             return s->capability;
471         case HPET_PERIOD:
472             return s->capability >> 32;
473         case HPET_CFG:
474             return s->config;
475         case HPET_CFG + 4:
476             DPRINTF("qemu: invalid HPET_CFG + 4 hpet_ram_readl\n");
477             return 0;
478         case HPET_COUNTER:
479             if (hpet_enabled(s)) {
480                 cur_tick = hpet_get_ticks(s);
481             } else {
482                 cur_tick = s->hpet_counter;
483             }
484             DPRINTF("qemu: reading counter  = %" PRIx64 "\n", cur_tick);
485             return cur_tick;
486         case HPET_COUNTER + 4:
487             if (hpet_enabled(s)) {
488                 cur_tick = hpet_get_ticks(s);
489             } else {
490                 cur_tick = s->hpet_counter;
491             }
492             DPRINTF("qemu: reading counter + 4  = %" PRIx64 "\n", cur_tick);
493             return cur_tick >> 32;
494         case HPET_STATUS:
495             return s->isr;
496         default:
497             DPRINTF("qemu: invalid hpet_ram_readl\n");
498             break;
499         }
500     }
501     return 0;
502 }
503 
504 static void hpet_ram_write(void *opaque, hwaddr addr,
505                            uint64_t value, unsigned size)
506 {
507     int i;
508     HPETState *s = opaque;
509     uint64_t old_val, new_val, val, index;
510 
511     DPRINTF("qemu: Enter hpet_ram_writel at %" PRIx64 " = %#x\n", addr, value);
512     index = addr;
513     old_val = hpet_ram_read(opaque, addr, 4);
514     new_val = value;
515 
516     /*address range of all TN regs*/
517     if (index >= 0x100 && index <= 0x3ff) {
518         uint8_t timer_id = (addr - 0x100) / 0x20;
519         HPETTimer *timer = &s->timer[timer_id];
520 
521         DPRINTF("qemu: hpet_ram_writel timer_id = %#x\n", timer_id);
522         if (timer_id > s->num_timers) {
523             DPRINTF("qemu: timer id out of range\n");
524             return;
525         }
526         switch ((addr - 0x100) % 0x20) {
527         case HPET_TN_CFG:
528             DPRINTF("qemu: hpet_ram_writel HPET_TN_CFG\n");
529             if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
530                 update_irq(timer, 0);
531             }
532             val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
533             timer->config = (timer->config & 0xffffffff00000000ULL) | val;
534             if (new_val & HPET_TN_32BIT) {
535                 timer->cmp = (uint32_t)timer->cmp;
536                 timer->period = (uint32_t)timer->period;
537             }
538             if (activating_bit(old_val, new_val, HPET_TN_ENABLE) &&
539                 hpet_enabled(s)) {
540                 hpet_set_timer(timer);
541             } else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
542                 hpet_del_timer(timer);
543             }
544             break;
545         case HPET_TN_CFG + 4: // Interrupt capabilities
546             DPRINTF("qemu: invalid HPET_TN_CFG+4 write\n");
547             break;
548         case HPET_TN_CMP: // comparator register
549             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP\n");
550             if (timer->config & HPET_TN_32BIT) {
551                 new_val = (uint32_t)new_val;
552             }
553             if (!timer_is_periodic(timer)
554                 || (timer->config & HPET_TN_SETVAL)) {
555                 timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;
556             }
557             if (timer_is_periodic(timer)) {
558                 /*
559                  * FIXME: Clamp period to reasonable min value?
560                  * Clamp period to reasonable max value
561                  */
562                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
563                 timer->period =
564                     (timer->period & 0xffffffff00000000ULL) | new_val;
565             }
566             timer->config &= ~HPET_TN_SETVAL;
567             if (hpet_enabled(s)) {
568                 hpet_set_timer(timer);
569             }
570             break;
571         case HPET_TN_CMP + 4: // comparator register high order
572             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");
573             if (!timer_is_periodic(timer)
574                 || (timer->config & HPET_TN_SETVAL)) {
575                 timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;
576             } else {
577                 /*
578                  * FIXME: Clamp period to reasonable min value?
579                  * Clamp period to reasonable max value
580                  */
581                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
582                 timer->period =
583                     (timer->period & 0xffffffffULL) | new_val << 32;
584                 }
585                 timer->config &= ~HPET_TN_SETVAL;
586                 if (hpet_enabled(s)) {
587                     hpet_set_timer(timer);
588                 }
589                 break;
590         case HPET_TN_ROUTE:
591             timer->fsb = (timer->fsb & 0xffffffff00000000ULL) | new_val;
592             break;
593         case HPET_TN_ROUTE + 4:
594             timer->fsb = (new_val << 32) | (timer->fsb & 0xffffffff);
595             break;
596         default:
597             DPRINTF("qemu: invalid hpet_ram_writel\n");
598             break;
599         }
600         return;
601     } else {
602         switch (index) {
603         case HPET_ID:
604             return;
605         case HPET_CFG:
606             val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
607             s->config = (s->config & 0xffffffff00000000ULL) | val;
608             if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
609                 /* Enable main counter and interrupt generation. */
610                 s->hpet_offset =
611                     ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
612                 for (i = 0; i < s->num_timers; i++) {
613                     if ((&s->timer[i])->cmp != ~0ULL) {
614                         hpet_set_timer(&s->timer[i]);
615                     }
616                 }
617             } else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
618                 /* Halt main counter and disable interrupt generation. */
619                 s->hpet_counter = hpet_get_ticks(s);
620                 for (i = 0; i < s->num_timers; i++) {
621                     hpet_del_timer(&s->timer[i]);
622                 }
623             }
624             /* i8254 and RTC output pins are disabled
625              * when HPET is in legacy mode */
626             if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
627                 qemu_set_irq(s->pit_enabled, 0);
628                 qemu_irq_lower(s->irqs[0]);
629                 qemu_irq_lower(s->irqs[RTC_ISA_IRQ]);
630             } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
631                 qemu_irq_lower(s->irqs[0]);
632                 qemu_set_irq(s->pit_enabled, 1);
633                 qemu_set_irq(s->irqs[RTC_ISA_IRQ], s->rtc_irq_level);
634             }
635             break;
636         case HPET_CFG + 4:
637             DPRINTF("qemu: invalid HPET_CFG+4 write\n");
638             break;
639         case HPET_STATUS:
640             val = new_val & s->isr;
641             for (i = 0; i < s->num_timers; i++) {
642                 if (val & (1 << i)) {
643                     update_irq(&s->timer[i], 0);
644                 }
645             }
646             break;
647         case HPET_COUNTER:
648             if (hpet_enabled(s)) {
649                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
650             }
651             s->hpet_counter =
652                 (s->hpet_counter & 0xffffffff00000000ULL) | value;
653             DPRINTF("qemu: HPET counter written. ctr = %#x -> %" PRIx64 "\n",
654                     value, s->hpet_counter);
655             break;
656         case HPET_COUNTER + 4:
657             if (hpet_enabled(s)) {
658                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
659             }
660             s->hpet_counter =
661                 (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);
662             DPRINTF("qemu: HPET counter + 4 written. ctr = %#x -> %" PRIx64 "\n",
663                     value, s->hpet_counter);
664             break;
665         default:
666             DPRINTF("qemu: invalid hpet_ram_writel\n");
667             break;
668         }
669     }
670 }
671 
672 static const MemoryRegionOps hpet_ram_ops = {
673     .read = hpet_ram_read,
674     .write = hpet_ram_write,
675     .valid = {
676         .min_access_size = 4,
677         .max_access_size = 4,
678     },
679     .endianness = DEVICE_NATIVE_ENDIAN,
680 };
681 
682 static void hpet_reset(DeviceState *d)
683 {
684     HPETState *s = HPET(d);
685     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
686     int i;
687 
688     for (i = 0; i < s->num_timers; i++) {
689         HPETTimer *timer = &s->timer[i];
690 
691         hpet_del_timer(timer);
692         timer->cmp = ~0ULL;
693         timer->config = HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;
694         if (s->flags & (1 << HPET_MSI_SUPPORT)) {
695             timer->config |= HPET_TN_FSB_CAP;
696         }
697         /* advertise availability of ioapic int */
698         timer->config |=  (uint64_t)s->intcap << 32;
699         timer->period = 0ULL;
700         timer->wrap_flag = 0;
701     }
702 
703     qemu_set_irq(s->pit_enabled, 1);
704     s->hpet_counter = 0ULL;
705     s->hpet_offset = 0ULL;
706     s->config = 0ULL;
707     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
708     hpet_cfg.hpet[s->hpet_id].address = sbd->mmio[0].addr;
709 
710     /* to document that the RTC lowers its output on reset as well */
711     s->rtc_irq_level = 0;
712 }
713 
714 static void hpet_handle_legacy_irq(void *opaque, int n, int level)
715 {
716     HPETState *s = HPET(opaque);
717 
718     if (n == HPET_LEGACY_PIT_INT) {
719         if (!hpet_in_legacy_mode(s)) {
720             qemu_set_irq(s->irqs[0], level);
721         }
722     } else {
723         s->rtc_irq_level = level;
724         if (!hpet_in_legacy_mode(s)) {
725             qemu_set_irq(s->irqs[RTC_ISA_IRQ], level);
726         }
727     }
728 }
729 
730 static void hpet_init(Object *obj)
731 {
732     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
733     HPETState *s = HPET(obj);
734 
735     /* HPET Area */
736     memory_region_init_io(&s->iomem, obj, &hpet_ram_ops, s, "hpet", HPET_LEN);
737     sysbus_init_mmio(sbd, &s->iomem);
738 }
739 
740 static void hpet_realize(DeviceState *dev, Error **errp)
741 {
742     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
743     HPETState *s = HPET(dev);
744     int i;
745     HPETTimer *timer;
746 
747     if (!s->intcap) {
748         warn_report("Hpet's intcap not initialized");
749     }
750     if (hpet_cfg.count == UINT8_MAX) {
751         /* first instance */
752         hpet_cfg.count = 0;
753     }
754 
755     if (hpet_cfg.count == 8) {
756         error_setg(errp, "Only 8 instances of HPET is allowed");
757         return;
758     }
759 
760     s->hpet_id = hpet_cfg.count++;
761 
762     for (i = 0; i < HPET_NUM_IRQ_ROUTES; i++) {
763         sysbus_init_irq(sbd, &s->irqs[i]);
764     }
765 
766     if (s->num_timers < HPET_MIN_TIMERS) {
767         s->num_timers = HPET_MIN_TIMERS;
768     } else if (s->num_timers > HPET_MAX_TIMERS) {
769         s->num_timers = HPET_MAX_TIMERS;
770     }
771     for (i = 0; i < HPET_MAX_TIMERS; i++) {
772         timer = &s->timer[i];
773         timer->qemu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, hpet_timer, timer);
774         timer->tn = i;
775         timer->state = s;
776     }
777 
778     /* 64-bit main counter; LegacyReplacementRoute. */
779     s->capability = 0x8086a001ULL;
780     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
781     s->capability |= ((uint64_t)(HPET_CLK_PERIOD * FS_PER_NS) << 32);
782 
783     qdev_init_gpio_in(dev, hpet_handle_legacy_irq, 2);
784     qdev_init_gpio_out(dev, &s->pit_enabled, 1);
785 }
786 
787 static Property hpet_device_properties[] = {
788     DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
789     DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
790     DEFINE_PROP_UINT32(HPET_INTCAP, HPETState, intcap, 0),
791     DEFINE_PROP_BOOL("hpet-offset-saved", HPETState, hpet_offset_saved, true),
792     DEFINE_PROP_END_OF_LIST(),
793 };
794 
795 static void hpet_device_class_init(ObjectClass *klass, void *data)
796 {
797     DeviceClass *dc = DEVICE_CLASS(klass);
798 
799     dc->realize = hpet_realize;
800     dc->reset = hpet_reset;
801     dc->vmsd = &vmstate_hpet;
802     dc->props = hpet_device_properties;
803 }
804 
805 static const TypeInfo hpet_device_info = {
806     .name          = TYPE_HPET,
807     .parent        = TYPE_SYS_BUS_DEVICE,
808     .instance_size = sizeof(HPETState),
809     .instance_init = hpet_init,
810     .class_init    = hpet_device_class_init,
811 };
812 
813 static void hpet_register_types(void)
814 {
815     type_register_static(&hpet_device_info);
816 }
817 
818 type_init(hpet_register_types)
819