xref: /openbmc/qemu/hw/timer/hpet.c (revision effd60c8)
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 2.1 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 "qapi/error.h"
31 #include "qemu/error-report.h"
32 #include "qemu/timer.h"
33 #include "hw/qdev-properties.h"
34 #include "hw/timer/hpet.h"
35 #include "hw/sysbus.h"
36 #include "hw/rtc/mc146818rtc.h"
37 #include "hw/rtc/mc146818rtc_regs.h"
38 #include "migration/vmstate.h"
39 #include "hw/timer/i8254.h"
40 #include "exec/address-spaces.h"
41 #include "qom/object.h"
42 #include "trace.h"
43 
44 #define HPET_MSI_SUPPORT        0
45 
46 OBJECT_DECLARE_SIMPLE_TYPE(HPETState, HPET)
47 
48 struct HPETState;
49 typedef struct HPETTimer {  /* timers */
50     uint8_t tn;             /*timer number*/
51     QEMUTimer *qemu_timer;
52     struct HPETState *state;
53     /* Memory-mapped, software visible timer registers */
54     uint64_t config;        /* configuration/cap */
55     uint64_t cmp;           /* comparator */
56     uint64_t fsb;           /* FSB route */
57     /* Hidden register state */
58     uint64_t period;        /* Last value written to comparator */
59     uint8_t wrap_flag;      /* timer pop will indicate wrap for one-shot 32-bit
60                              * mode. Next pop will be actual timer expiration.
61                              */
62 } HPETTimer;
63 
64 struct HPETState {
65     /*< private >*/
66     SysBusDevice parent_obj;
67     /*< public >*/
68 
69     MemoryRegion iomem;
70     uint64_t hpet_offset;
71     bool hpet_offset_saved;
72     qemu_irq irqs[HPET_NUM_IRQ_ROUTES];
73     uint32_t flags;
74     uint8_t rtc_irq_level;
75     qemu_irq pit_enabled;
76     uint8_t num_timers;
77     uint32_t intcap;
78     HPETTimer timer[HPET_MAX_TIMERS];
79 
80     /* Memory-mapped, software visible registers */
81     uint64_t capability;        /* capabilities */
82     uint64_t config;            /* configuration */
83     uint64_t isr;               /* interrupt status reg */
84     uint64_t hpet_counter;      /* main counter */
85     uint8_t  hpet_id;           /* instance id */
86 };
87 
88 static uint32_t hpet_in_legacy_mode(HPETState *s)
89 {
90     return s->config & HPET_CFG_LEGACY;
91 }
92 
93 static uint32_t timer_int_route(struct HPETTimer *timer)
94 {
95     return (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;
96 }
97 
98 static uint32_t timer_fsb_route(HPETTimer *t)
99 {
100     return t->config & HPET_TN_FSB_ENABLE;
101 }
102 
103 static uint32_t hpet_enabled(HPETState *s)
104 {
105     return s->config & HPET_CFG_ENABLE;
106 }
107 
108 static uint32_t timer_is_periodic(HPETTimer *t)
109 {
110     return t->config & HPET_TN_PERIODIC;
111 }
112 
113 static uint32_t timer_enabled(HPETTimer *t)
114 {
115     return t->config & HPET_TN_ENABLE;
116 }
117 
118 static uint32_t hpet_time_after(uint64_t a, uint64_t b)
119 {
120     return ((int32_t)(b - a) < 0);
121 }
122 
123 static uint32_t hpet_time_after64(uint64_t a, uint64_t b)
124 {
125     return ((int64_t)(b - a) < 0);
126 }
127 
128 static uint64_t ticks_to_ns(uint64_t value)
129 {
130     return value * HPET_CLK_PERIOD;
131 }
132 
133 static uint64_t ns_to_ticks(uint64_t value)
134 {
135     return value / HPET_CLK_PERIOD;
136 }
137 
138 static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)
139 {
140     new &= mask;
141     new |= old & ~mask;
142     return new;
143 }
144 
145 static int activating_bit(uint64_t old, uint64_t new, uint64_t mask)
146 {
147     return (!(old & mask) && (new & mask));
148 }
149 
150 static int deactivating_bit(uint64_t old, uint64_t new, uint64_t mask)
151 {
152     return ((old & mask) && !(new & mask));
153 }
154 
155 static uint64_t hpet_get_ticks(HPETState *s)
156 {
157     return ns_to_ticks(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->hpet_offset);
158 }
159 
160 /*
161  * calculate diff between comparator value and current ticks
162  */
163 static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
164 {
165 
166     if (t->config & HPET_TN_32BIT) {
167         uint32_t diff, cmp;
168 
169         cmp = (uint32_t)t->cmp;
170         diff = cmp - (uint32_t)current;
171         diff = (int32_t)diff > 0 ? diff : (uint32_t)1;
172         return (uint64_t)diff;
173     } else {
174         uint64_t diff, cmp;
175 
176         cmp = t->cmp;
177         diff = cmp - current;
178         diff = (int64_t)diff > 0 ? diff : (uint64_t)1;
179         return diff;
180     }
181 }
182 
183 static void update_irq(struct HPETTimer *timer, int set)
184 {
185     uint64_t mask;
186     HPETState *s;
187     int route;
188 
189     if (timer->tn <= 1 && hpet_in_legacy_mode(timer->state)) {
190         /* if LegacyReplacementRoute bit is set, HPET specification requires
191          * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
192          * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.
193          */
194         route = (timer->tn == 0) ? 0 : RTC_ISA_IRQ;
195     } else {
196         route = timer_int_route(timer);
197     }
198     s = timer->state;
199     mask = 1 << timer->tn;
200     if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
201         s->isr &= ~mask;
202         if (!timer_fsb_route(timer)) {
203             qemu_irq_lower(s->irqs[route]);
204         }
205     } else if (timer_fsb_route(timer)) {
206         address_space_stl_le(&address_space_memory, timer->fsb >> 32,
207                              timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
208                              NULL);
209     } else if (timer->config & HPET_TN_TYPE_LEVEL) {
210         s->isr |= mask;
211         qemu_irq_raise(s->irqs[route]);
212     } else {
213         s->isr &= ~mask;
214         qemu_irq_pulse(s->irqs[route]);
215     }
216 }
217 
218 static int hpet_pre_save(void *opaque)
219 {
220     HPETState *s = opaque;
221 
222     /* save current counter value */
223     if (hpet_enabled(s)) {
224         s->hpet_counter = hpet_get_ticks(s);
225     }
226 
227     return 0;
228 }
229 
230 static int hpet_pre_load(void *opaque)
231 {
232     HPETState *s = opaque;
233 
234     /* version 1 only supports 3, later versions will load the actual value */
235     s->num_timers = HPET_MIN_TIMERS;
236     return 0;
237 }
238 
239 static bool hpet_validate_num_timers(void *opaque, int version_id)
240 {
241     HPETState *s = opaque;
242 
243     if (s->num_timers < HPET_MIN_TIMERS) {
244         return false;
245     } else if (s->num_timers > HPET_MAX_TIMERS) {
246         return false;
247     }
248     return true;
249 }
250 
251 static int hpet_post_load(void *opaque, int version_id)
252 {
253     HPETState *s = opaque;
254 
255     /* Recalculate the offset between the main counter and guest time */
256     if (!s->hpet_offset_saved) {
257         s->hpet_offset = ticks_to_ns(s->hpet_counter)
258                         - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
259     }
260 
261     /* Push number of timers into capability returned via HPET_ID */
262     s->capability &= ~HPET_ID_NUM_TIM_MASK;
263     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
264     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
265 
266     /* Derive HPET_MSI_SUPPORT from the capability of the first timer. */
267     s->flags &= ~(1 << HPET_MSI_SUPPORT);
268     if (s->timer[0].config & HPET_TN_FSB_CAP) {
269         s->flags |= 1 << HPET_MSI_SUPPORT;
270     }
271     return 0;
272 }
273 
274 static bool hpet_offset_needed(void *opaque)
275 {
276     HPETState *s = opaque;
277 
278     return hpet_enabled(s) && s->hpet_offset_saved;
279 }
280 
281 static bool hpet_rtc_irq_level_needed(void *opaque)
282 {
283     HPETState *s = opaque;
284 
285     return s->rtc_irq_level != 0;
286 }
287 
288 static const VMStateDescription vmstate_hpet_rtc_irq_level = {
289     .name = "hpet/rtc_irq_level",
290     .version_id = 1,
291     .minimum_version_id = 1,
292     .needed = hpet_rtc_irq_level_needed,
293     .fields = (const VMStateField[]) {
294         VMSTATE_UINT8(rtc_irq_level, HPETState),
295         VMSTATE_END_OF_LIST()
296     }
297 };
298 
299 static const VMStateDescription vmstate_hpet_offset = {
300     .name = "hpet/offset",
301     .version_id = 1,
302     .minimum_version_id = 1,
303     .needed = hpet_offset_needed,
304     .fields = (const VMStateField[]) {
305         VMSTATE_UINT64(hpet_offset, HPETState),
306         VMSTATE_END_OF_LIST()
307     }
308 };
309 
310 static const VMStateDescription vmstate_hpet_timer = {
311     .name = "hpet_timer",
312     .version_id = 1,
313     .minimum_version_id = 1,
314     .fields = (const VMStateField[]) {
315         VMSTATE_UINT8(tn, HPETTimer),
316         VMSTATE_UINT64(config, HPETTimer),
317         VMSTATE_UINT64(cmp, HPETTimer),
318         VMSTATE_UINT64(fsb, HPETTimer),
319         VMSTATE_UINT64(period, HPETTimer),
320         VMSTATE_UINT8(wrap_flag, HPETTimer),
321         VMSTATE_TIMER_PTR(qemu_timer, HPETTimer),
322         VMSTATE_END_OF_LIST()
323     }
324 };
325 
326 static const VMStateDescription vmstate_hpet = {
327     .name = "hpet",
328     .version_id = 2,
329     .minimum_version_id = 1,
330     .pre_save = hpet_pre_save,
331     .pre_load = hpet_pre_load,
332     .post_load = hpet_post_load,
333     .fields = (const VMStateField[]) {
334         VMSTATE_UINT64(config, HPETState),
335         VMSTATE_UINT64(isr, HPETState),
336         VMSTATE_UINT64(hpet_counter, HPETState),
337         VMSTATE_UINT8_V(num_timers, HPETState, 2),
338         VMSTATE_VALIDATE("num_timers in range", hpet_validate_num_timers),
339         VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0,
340                                     vmstate_hpet_timer, HPETTimer),
341         VMSTATE_END_OF_LIST()
342     },
343     .subsections = (const VMStateDescription * const []) {
344         &vmstate_hpet_rtc_irq_level,
345         &vmstate_hpet_offset,
346         NULL
347     }
348 };
349 
350 static void hpet_arm(HPETTimer *t, uint64_t ticks)
351 {
352     if (ticks < ns_to_ticks(INT64_MAX / 2)) {
353         timer_mod(t->qemu_timer,
354                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ticks_to_ns(ticks));
355     } else {
356         timer_del(t->qemu_timer);
357     }
358 }
359 
360 /*
361  * timer expiration callback
362  */
363 static void hpet_timer(void *opaque)
364 {
365     HPETTimer *t = opaque;
366     uint64_t diff;
367 
368     uint64_t period = t->period;
369     uint64_t cur_tick = hpet_get_ticks(t->state);
370 
371     if (timer_is_periodic(t) && period != 0) {
372         if (t->config & HPET_TN_32BIT) {
373             while (hpet_time_after(cur_tick, t->cmp)) {
374                 t->cmp = (uint32_t)(t->cmp + t->period);
375             }
376         } else {
377             while (hpet_time_after64(cur_tick, t->cmp)) {
378                 t->cmp += period;
379             }
380         }
381         diff = hpet_calculate_diff(t, cur_tick);
382         hpet_arm(t, diff);
383     } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
384         if (t->wrap_flag) {
385             diff = hpet_calculate_diff(t, cur_tick);
386             hpet_arm(t, diff);
387             t->wrap_flag = 0;
388         }
389     }
390     update_irq(t, 1);
391 }
392 
393 static void hpet_set_timer(HPETTimer *t)
394 {
395     uint64_t diff;
396     uint32_t wrap_diff;  /* how many ticks until we wrap? */
397     uint64_t cur_tick = hpet_get_ticks(t->state);
398 
399     /* whenever new timer is being set up, make sure wrap_flag is 0 */
400     t->wrap_flag = 0;
401     diff = hpet_calculate_diff(t, cur_tick);
402 
403     /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
404      * counter wraps in addition to an interrupt with comparator match.
405      */
406     if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
407         wrap_diff = 0xffffffff - (uint32_t)cur_tick;
408         if (wrap_diff < (uint32_t)diff) {
409             diff = wrap_diff;
410             t->wrap_flag = 1;
411         }
412     }
413     hpet_arm(t, diff);
414 }
415 
416 static void hpet_del_timer(HPETTimer *t)
417 {
418     timer_del(t->qemu_timer);
419     update_irq(t, 0);
420 }
421 
422 static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
423                               unsigned size)
424 {
425     HPETState *s = opaque;
426     uint64_t cur_tick, index;
427 
428     trace_hpet_ram_read(addr);
429     index = addr;
430     /*address range of all TN regs*/
431     if (index >= 0x100 && index <= 0x3ff) {
432         uint8_t timer_id = (addr - 0x100) / 0x20;
433         HPETTimer *timer = &s->timer[timer_id];
434 
435         if (timer_id > s->num_timers) {
436             trace_hpet_timer_id_out_of_range(timer_id);
437             return 0;
438         }
439 
440         switch ((addr - 0x100) % 0x20) {
441         case HPET_TN_CFG:
442             return timer->config;
443         case HPET_TN_CFG + 4: // Interrupt capabilities
444             return timer->config >> 32;
445         case HPET_TN_CMP: // comparator register
446             return timer->cmp;
447         case HPET_TN_CMP + 4:
448             return timer->cmp >> 32;
449         case HPET_TN_ROUTE:
450             return timer->fsb;
451         case HPET_TN_ROUTE + 4:
452             return timer->fsb >> 32;
453         default:
454             trace_hpet_ram_read_invalid();
455             break;
456         }
457     } else {
458         switch (index) {
459         case HPET_ID:
460             return s->capability;
461         case HPET_PERIOD:
462             return s->capability >> 32;
463         case HPET_CFG:
464             return s->config;
465         case HPET_CFG + 4:
466             trace_hpet_invalid_hpet_cfg(4);
467             return 0;
468         case HPET_COUNTER:
469             if (hpet_enabled(s)) {
470                 cur_tick = hpet_get_ticks(s);
471             } else {
472                 cur_tick = s->hpet_counter;
473             }
474             trace_hpet_ram_read_reading_counter(0, cur_tick);
475             return cur_tick;
476         case HPET_COUNTER + 4:
477             if (hpet_enabled(s)) {
478                 cur_tick = hpet_get_ticks(s);
479             } else {
480                 cur_tick = s->hpet_counter;
481             }
482             trace_hpet_ram_read_reading_counter(4, cur_tick);
483             return cur_tick >> 32;
484         case HPET_STATUS:
485             return s->isr;
486         default:
487             trace_hpet_ram_read_invalid();
488             break;
489         }
490     }
491     return 0;
492 }
493 
494 static void hpet_ram_write(void *opaque, hwaddr addr,
495                            uint64_t value, unsigned size)
496 {
497     int i;
498     HPETState *s = opaque;
499     uint64_t old_val, new_val, val, index;
500 
501     trace_hpet_ram_write(addr, value);
502     index = addr;
503     old_val = hpet_ram_read(opaque, addr, 4);
504     new_val = value;
505 
506     /*address range of all TN regs*/
507     if (index >= 0x100 && index <= 0x3ff) {
508         uint8_t timer_id = (addr - 0x100) / 0x20;
509         HPETTimer *timer = &s->timer[timer_id];
510 
511         trace_hpet_ram_write_timer_id(timer_id);
512         if (timer_id > s->num_timers) {
513             trace_hpet_timer_id_out_of_range(timer_id);
514             return;
515         }
516         switch ((addr - 0x100) % 0x20) {
517         case HPET_TN_CFG:
518             trace_hpet_ram_write_tn_cfg();
519             if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
520                 update_irq(timer, 0);
521             }
522             val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
523             timer->config = (timer->config & 0xffffffff00000000ULL) | val;
524             if (new_val & HPET_TN_32BIT) {
525                 timer->cmp = (uint32_t)timer->cmp;
526                 timer->period = (uint32_t)timer->period;
527             }
528             if (activating_bit(old_val, new_val, HPET_TN_ENABLE) &&
529                 hpet_enabled(s)) {
530                 hpet_set_timer(timer);
531             } else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
532                 hpet_del_timer(timer);
533             }
534             break;
535         case HPET_TN_CFG + 4: // Interrupt capabilities
536             trace_hpet_ram_write_invalid_tn_cfg(4);
537             break;
538         case HPET_TN_CMP: // comparator register
539             trace_hpet_ram_write_tn_cmp(0);
540             if (timer->config & HPET_TN_32BIT) {
541                 new_val = (uint32_t)new_val;
542             }
543             if (!timer_is_periodic(timer)
544                 || (timer->config & HPET_TN_SETVAL)) {
545                 timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;
546             }
547             if (timer_is_periodic(timer)) {
548                 /*
549                  * FIXME: Clamp period to reasonable min value?
550                  * Clamp period to reasonable max value
551                  */
552                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
553                 timer->period =
554                     (timer->period & 0xffffffff00000000ULL) | new_val;
555             }
556             timer->config &= ~HPET_TN_SETVAL;
557             if (hpet_enabled(s)) {
558                 hpet_set_timer(timer);
559             }
560             break;
561         case HPET_TN_CMP + 4: // comparator register high order
562             trace_hpet_ram_write_tn_cmp(4);
563             if (!timer_is_periodic(timer)
564                 || (timer->config & HPET_TN_SETVAL)) {
565                 timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;
566             } else {
567                 /*
568                  * FIXME: Clamp period to reasonable min value?
569                  * Clamp period to reasonable max value
570                  */
571                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
572                 timer->period =
573                     (timer->period & 0xffffffffULL) | new_val << 32;
574                 }
575                 timer->config &= ~HPET_TN_SETVAL;
576                 if (hpet_enabled(s)) {
577                     hpet_set_timer(timer);
578                 }
579                 break;
580         case HPET_TN_ROUTE:
581             timer->fsb = (timer->fsb & 0xffffffff00000000ULL) | new_val;
582             break;
583         case HPET_TN_ROUTE + 4:
584             timer->fsb = (new_val << 32) | (timer->fsb & 0xffffffff);
585             break;
586         default:
587             trace_hpet_ram_write_invalid();
588             break;
589         }
590         return;
591     } else {
592         switch (index) {
593         case HPET_ID:
594             return;
595         case HPET_CFG:
596             val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
597             s->config = (s->config & 0xffffffff00000000ULL) | val;
598             if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
599                 /* Enable main counter and interrupt generation. */
600                 s->hpet_offset =
601                     ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
602                 for (i = 0; i < s->num_timers; i++) {
603                     if ((&s->timer[i])->cmp != ~0ULL) {
604                         hpet_set_timer(&s->timer[i]);
605                     }
606                 }
607             } else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
608                 /* Halt main counter and disable interrupt generation. */
609                 s->hpet_counter = hpet_get_ticks(s);
610                 for (i = 0; i < s->num_timers; i++) {
611                     hpet_del_timer(&s->timer[i]);
612                 }
613             }
614             /* i8254 and RTC output pins are disabled
615              * when HPET is in legacy mode */
616             if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
617                 qemu_set_irq(s->pit_enabled, 0);
618                 qemu_irq_lower(s->irqs[0]);
619                 qemu_irq_lower(s->irqs[RTC_ISA_IRQ]);
620             } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
621                 qemu_irq_lower(s->irqs[0]);
622                 qemu_set_irq(s->pit_enabled, 1);
623                 qemu_set_irq(s->irqs[RTC_ISA_IRQ], s->rtc_irq_level);
624             }
625             break;
626         case HPET_CFG + 4:
627             trace_hpet_invalid_hpet_cfg(4);
628             break;
629         case HPET_STATUS:
630             val = new_val & s->isr;
631             for (i = 0; i < s->num_timers; i++) {
632                 if (val & (1 << i)) {
633                     update_irq(&s->timer[i], 0);
634                 }
635             }
636             break;
637         case HPET_COUNTER:
638             if (hpet_enabled(s)) {
639                 trace_hpet_ram_write_counter_write_while_enabled();
640             }
641             s->hpet_counter =
642                 (s->hpet_counter & 0xffffffff00000000ULL) | value;
643             trace_hpet_ram_write_counter_written(0, value, s->hpet_counter);
644             break;
645         case HPET_COUNTER + 4:
646             trace_hpet_ram_write_counter_write_while_enabled();
647             s->hpet_counter =
648                 (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);
649             trace_hpet_ram_write_counter_written(4, value, s->hpet_counter);
650             break;
651         default:
652             trace_hpet_ram_write_invalid();
653             break;
654         }
655     }
656 }
657 
658 static const MemoryRegionOps hpet_ram_ops = {
659     .read = hpet_ram_read,
660     .write = hpet_ram_write,
661     .valid = {
662         .min_access_size = 4,
663         .max_access_size = 4,
664     },
665     .endianness = DEVICE_NATIVE_ENDIAN,
666 };
667 
668 static void hpet_reset(DeviceState *d)
669 {
670     HPETState *s = HPET(d);
671     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
672     int i;
673 
674     for (i = 0; i < s->num_timers; i++) {
675         HPETTimer *timer = &s->timer[i];
676 
677         hpet_del_timer(timer);
678         timer->cmp = ~0ULL;
679         timer->config = HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;
680         if (s->flags & (1 << HPET_MSI_SUPPORT)) {
681             timer->config |= HPET_TN_FSB_CAP;
682         }
683         /* advertise availability of ioapic int */
684         timer->config |=  (uint64_t)s->intcap << 32;
685         timer->period = 0ULL;
686         timer->wrap_flag = 0;
687     }
688 
689     qemu_set_irq(s->pit_enabled, 1);
690     s->hpet_counter = 0ULL;
691     s->hpet_offset = 0ULL;
692     s->config = 0ULL;
693     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
694     hpet_cfg.hpet[s->hpet_id].address = sbd->mmio[0].addr;
695 
696     /* to document that the RTC lowers its output on reset as well */
697     s->rtc_irq_level = 0;
698 }
699 
700 static void hpet_handle_legacy_irq(void *opaque, int n, int level)
701 {
702     HPETState *s = HPET(opaque);
703 
704     if (n == HPET_LEGACY_PIT_INT) {
705         if (!hpet_in_legacy_mode(s)) {
706             qemu_set_irq(s->irqs[0], level);
707         }
708     } else {
709         s->rtc_irq_level = level;
710         if (!hpet_in_legacy_mode(s)) {
711             qemu_set_irq(s->irqs[RTC_ISA_IRQ], level);
712         }
713     }
714 }
715 
716 static void hpet_init(Object *obj)
717 {
718     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
719     HPETState *s = HPET(obj);
720 
721     /* HPET Area */
722     memory_region_init_io(&s->iomem, obj, &hpet_ram_ops, s, "hpet", HPET_LEN);
723     sysbus_init_mmio(sbd, &s->iomem);
724 }
725 
726 static void hpet_realize(DeviceState *dev, Error **errp)
727 {
728     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
729     HPETState *s = HPET(dev);
730     int i;
731     HPETTimer *timer;
732 
733     if (!s->intcap) {
734         warn_report("Hpet's intcap not initialized");
735     }
736     if (hpet_cfg.count == UINT8_MAX) {
737         /* first instance */
738         hpet_cfg.count = 0;
739     }
740 
741     if (hpet_cfg.count == 8) {
742         error_setg(errp, "Only 8 instances of HPET is allowed");
743         return;
744     }
745 
746     s->hpet_id = hpet_cfg.count++;
747 
748     for (i = 0; i < HPET_NUM_IRQ_ROUTES; i++) {
749         sysbus_init_irq(sbd, &s->irqs[i]);
750     }
751 
752     if (s->num_timers < HPET_MIN_TIMERS) {
753         s->num_timers = HPET_MIN_TIMERS;
754     } else if (s->num_timers > HPET_MAX_TIMERS) {
755         s->num_timers = HPET_MAX_TIMERS;
756     }
757     for (i = 0; i < HPET_MAX_TIMERS; i++) {
758         timer = &s->timer[i];
759         timer->qemu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, hpet_timer, timer);
760         timer->tn = i;
761         timer->state = s;
762     }
763 
764     /* 64-bit main counter; LegacyReplacementRoute. */
765     s->capability = 0x8086a001ULL;
766     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
767     s->capability |= ((uint64_t)(HPET_CLK_PERIOD * FS_PER_NS) << 32);
768 
769     qdev_init_gpio_in(dev, hpet_handle_legacy_irq, 2);
770     qdev_init_gpio_out(dev, &s->pit_enabled, 1);
771 }
772 
773 static Property hpet_device_properties[] = {
774     DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
775     DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
776     DEFINE_PROP_UINT32(HPET_INTCAP, HPETState, intcap, 0),
777     DEFINE_PROP_BOOL("hpet-offset-saved", HPETState, hpet_offset_saved, true),
778     DEFINE_PROP_END_OF_LIST(),
779 };
780 
781 static void hpet_device_class_init(ObjectClass *klass, void *data)
782 {
783     DeviceClass *dc = DEVICE_CLASS(klass);
784 
785     dc->realize = hpet_realize;
786     dc->reset = hpet_reset;
787     dc->vmsd = &vmstate_hpet;
788     device_class_set_props(dc, hpet_device_properties);
789 }
790 
791 static const TypeInfo hpet_device_info = {
792     .name          = TYPE_HPET,
793     .parent        = TYPE_SYS_BUS_DEVICE,
794     .instance_size = sizeof(HPETState),
795     .instance_init = hpet_init,
796     .class_init    = hpet_device_class_init,
797 };
798 
799 static void hpet_register_types(void)
800 {
801     type_register_static(&hpet_device_info);
802 }
803 
804 type_init(hpet_register_types)
805