xref: /openbmc/qemu/hw/timer/hpet.c (revision 834e8bf1)
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/rtc/mc146818rtc.h"
37 #include "hw/rtc/mc146818rtc_regs.h"
38 #include "migration/vmstate.h"
39 #include "hw/timer/i8254.h"
40 
41 //#define HPET_DEBUG
42 #ifdef HPET_DEBUG
43 #define DPRINTF printf
44 #else
45 #define DPRINTF(...)
46 #endif
47 
48 #define HPET_MSI_SUPPORT        0
49 
50 #define HPET(obj) OBJECT_CHECK(HPETState, (obj), TYPE_HPET)
51 
52 struct HPETState;
53 typedef struct HPETTimer {  /* timers */
54     uint8_t tn;             /*timer number*/
55     QEMUTimer *qemu_timer;
56     struct HPETState *state;
57     /* Memory-mapped, software visible timer registers */
58     uint64_t config;        /* configuration/cap */
59     uint64_t cmp;           /* comparator */
60     uint64_t fsb;           /* FSB route */
61     /* Hidden register state */
62     uint64_t period;        /* Last value written to comparator */
63     uint8_t wrap_flag;      /* timer pop will indicate wrap for one-shot 32-bit
64                              * mode. Next pop will be actual timer expiration.
65                              */
66 } HPETTimer;
67 
68 typedef struct HPETState {
69     /*< private >*/
70     SysBusDevice parent_obj;
71     /*< public >*/
72 
73     MemoryRegion iomem;
74     uint64_t hpet_offset;
75     bool hpet_offset_saved;
76     qemu_irq irqs[HPET_NUM_IRQ_ROUTES];
77     uint32_t flags;
78     uint8_t rtc_irq_level;
79     qemu_irq pit_enabled;
80     uint8_t num_timers;
81     uint32_t intcap;
82     HPETTimer timer[HPET_MAX_TIMERS];
83 
84     /* Memory-mapped, software visible registers */
85     uint64_t capability;        /* capabilities */
86     uint64_t config;            /* configuration */
87     uint64_t isr;               /* interrupt status reg */
88     uint64_t hpet_counter;      /* main counter */
89     uint8_t  hpet_id;           /* instance id */
90 } HPETState;
91 
92 static uint32_t hpet_in_legacy_mode(HPETState *s)
93 {
94     return s->config & HPET_CFG_LEGACY;
95 }
96 
97 static uint32_t timer_int_route(struct HPETTimer *timer)
98 {
99     return (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;
100 }
101 
102 static uint32_t timer_fsb_route(HPETTimer *t)
103 {
104     return t->config & HPET_TN_FSB_ENABLE;
105 }
106 
107 static uint32_t hpet_enabled(HPETState *s)
108 {
109     return s->config & HPET_CFG_ENABLE;
110 }
111 
112 static uint32_t timer_is_periodic(HPETTimer *t)
113 {
114     return t->config & HPET_TN_PERIODIC;
115 }
116 
117 static uint32_t timer_enabled(HPETTimer *t)
118 {
119     return t->config & HPET_TN_ENABLE;
120 }
121 
122 static uint32_t hpet_time_after(uint64_t a, uint64_t b)
123 {
124     return ((int32_t)(b - a) < 0);
125 }
126 
127 static uint32_t hpet_time_after64(uint64_t a, uint64_t b)
128 {
129     return ((int64_t)(b - a) < 0);
130 }
131 
132 static uint64_t ticks_to_ns(uint64_t value)
133 {
134     return value * HPET_CLK_PERIOD;
135 }
136 
137 static uint64_t ns_to_ticks(uint64_t value)
138 {
139     return value / HPET_CLK_PERIOD;
140 }
141 
142 static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)
143 {
144     new &= mask;
145     new |= old & ~mask;
146     return new;
147 }
148 
149 static int activating_bit(uint64_t old, uint64_t new, uint64_t mask)
150 {
151     return (!(old & mask) && (new & mask));
152 }
153 
154 static int deactivating_bit(uint64_t old, uint64_t new, uint64_t mask)
155 {
156     return ((old & mask) && !(new & mask));
157 }
158 
159 static uint64_t hpet_get_ticks(HPETState *s)
160 {
161     return ns_to_ticks(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->hpet_offset);
162 }
163 
164 /*
165  * calculate diff between comparator value and current ticks
166  */
167 static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
168 {
169 
170     if (t->config & HPET_TN_32BIT) {
171         uint32_t diff, cmp;
172 
173         cmp = (uint32_t)t->cmp;
174         diff = cmp - (uint32_t)current;
175         diff = (int32_t)diff > 0 ? diff : (uint32_t)1;
176         return (uint64_t)diff;
177     } else {
178         uint64_t diff, cmp;
179 
180         cmp = t->cmp;
181         diff = cmp - current;
182         diff = (int64_t)diff > 0 ? diff : (uint64_t)1;
183         return diff;
184     }
185 }
186 
187 static void update_irq(struct HPETTimer *timer, int set)
188 {
189     uint64_t mask;
190     HPETState *s;
191     int route;
192 
193     if (timer->tn <= 1 && hpet_in_legacy_mode(timer->state)) {
194         /* if LegacyReplacementRoute bit is set, HPET specification requires
195          * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
196          * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.
197          */
198         route = (timer->tn == 0) ? 0 : RTC_ISA_IRQ;
199     } else {
200         route = timer_int_route(timer);
201     }
202     s = timer->state;
203     mask = 1 << timer->tn;
204     if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
205         s->isr &= ~mask;
206         if (!timer_fsb_route(timer)) {
207             qemu_irq_lower(s->irqs[route]);
208         }
209     } else if (timer_fsb_route(timer)) {
210         address_space_stl_le(&address_space_memory, timer->fsb >> 32,
211                              timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
212                              NULL);
213     } else if (timer->config & HPET_TN_TYPE_LEVEL) {
214         s->isr |= mask;
215         qemu_irq_raise(s->irqs[route]);
216     } else {
217         s->isr &= ~mask;
218         qemu_irq_pulse(s->irqs[route]);
219     }
220 }
221 
222 static int hpet_pre_save(void *opaque)
223 {
224     HPETState *s = opaque;
225 
226     /* save current counter value */
227     if (hpet_enabled(s)) {
228         s->hpet_counter = hpet_get_ticks(s);
229     }
230 
231     return 0;
232 }
233 
234 static int hpet_pre_load(void *opaque)
235 {
236     HPETState *s = opaque;
237 
238     /* version 1 only supports 3, later versions will load the actual value */
239     s->num_timers = HPET_MIN_TIMERS;
240     return 0;
241 }
242 
243 static bool hpet_validate_num_timers(void *opaque, int version_id)
244 {
245     HPETState *s = opaque;
246 
247     if (s->num_timers < HPET_MIN_TIMERS) {
248         return false;
249     } else if (s->num_timers > HPET_MAX_TIMERS) {
250         return false;
251     }
252     return true;
253 }
254 
255 static int hpet_post_load(void *opaque, int version_id)
256 {
257     HPETState *s = opaque;
258 
259     /* Recalculate the offset between the main counter and guest time */
260     if (!s->hpet_offset_saved) {
261         s->hpet_offset = ticks_to_ns(s->hpet_counter)
262                         - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
263     }
264 
265     /* Push number of timers into capability returned via HPET_ID */
266     s->capability &= ~HPET_ID_NUM_TIM_MASK;
267     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
268     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
269 
270     /* Derive HPET_MSI_SUPPORT from the capability of the first timer. */
271     s->flags &= ~(1 << HPET_MSI_SUPPORT);
272     if (s->timer[0].config & HPET_TN_FSB_CAP) {
273         s->flags |= 1 << HPET_MSI_SUPPORT;
274     }
275     return 0;
276 }
277 
278 static bool hpet_offset_needed(void *opaque)
279 {
280     HPETState *s = opaque;
281 
282     return hpet_enabled(s) && s->hpet_offset_saved;
283 }
284 
285 static bool hpet_rtc_irq_level_needed(void *opaque)
286 {
287     HPETState *s = opaque;
288 
289     return s->rtc_irq_level != 0;
290 }
291 
292 static const VMStateDescription vmstate_hpet_rtc_irq_level = {
293     .name = "hpet/rtc_irq_level",
294     .version_id = 1,
295     .minimum_version_id = 1,
296     .needed = hpet_rtc_irq_level_needed,
297     .fields = (VMStateField[]) {
298         VMSTATE_UINT8(rtc_irq_level, HPETState),
299         VMSTATE_END_OF_LIST()
300     }
301 };
302 
303 static const VMStateDescription vmstate_hpet_offset = {
304     .name = "hpet/offset",
305     .version_id = 1,
306     .minimum_version_id = 1,
307     .needed = hpet_offset_needed,
308     .fields = (VMStateField[]) {
309         VMSTATE_UINT64(hpet_offset, HPETState),
310         VMSTATE_END_OF_LIST()
311     }
312 };
313 
314 static const VMStateDescription vmstate_hpet_timer = {
315     .name = "hpet_timer",
316     .version_id = 1,
317     .minimum_version_id = 1,
318     .fields = (VMStateField[]) {
319         VMSTATE_UINT8(tn, HPETTimer),
320         VMSTATE_UINT64(config, HPETTimer),
321         VMSTATE_UINT64(cmp, HPETTimer),
322         VMSTATE_UINT64(fsb, HPETTimer),
323         VMSTATE_UINT64(period, HPETTimer),
324         VMSTATE_UINT8(wrap_flag, HPETTimer),
325         VMSTATE_TIMER_PTR(qemu_timer, HPETTimer),
326         VMSTATE_END_OF_LIST()
327     }
328 };
329 
330 static const VMStateDescription vmstate_hpet = {
331     .name = "hpet",
332     .version_id = 2,
333     .minimum_version_id = 1,
334     .pre_save = hpet_pre_save,
335     .pre_load = hpet_pre_load,
336     .post_load = hpet_post_load,
337     .fields = (VMStateField[]) {
338         VMSTATE_UINT64(config, HPETState),
339         VMSTATE_UINT64(isr, HPETState),
340         VMSTATE_UINT64(hpet_counter, HPETState),
341         VMSTATE_UINT8_V(num_timers, HPETState, 2),
342         VMSTATE_VALIDATE("num_timers in range", hpet_validate_num_timers),
343         VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0,
344                                     vmstate_hpet_timer, HPETTimer),
345         VMSTATE_END_OF_LIST()
346     },
347     .subsections = (const VMStateDescription*[]) {
348         &vmstate_hpet_rtc_irq_level,
349         &vmstate_hpet_offset,
350         NULL
351     }
352 };
353 
354 /*
355  * timer expiration callback
356  */
357 static void hpet_timer(void *opaque)
358 {
359     HPETTimer *t = opaque;
360     uint64_t diff;
361 
362     uint64_t period = t->period;
363     uint64_t cur_tick = hpet_get_ticks(t->state);
364 
365     if (timer_is_periodic(t) && period != 0) {
366         if (t->config & HPET_TN_32BIT) {
367             while (hpet_time_after(cur_tick, t->cmp)) {
368                 t->cmp = (uint32_t)(t->cmp + t->period);
369             }
370         } else {
371             while (hpet_time_after64(cur_tick, t->cmp)) {
372                 t->cmp += period;
373             }
374         }
375         diff = hpet_calculate_diff(t, cur_tick);
376         timer_mod(t->qemu_timer,
377                        qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
378     } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
379         if (t->wrap_flag) {
380             diff = hpet_calculate_diff(t, cur_tick);
381             timer_mod(t->qemu_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
382                            (int64_t)ticks_to_ns(diff));
383             t->wrap_flag = 0;
384         }
385     }
386     update_irq(t, 1);
387 }
388 
389 static void hpet_set_timer(HPETTimer *t)
390 {
391     uint64_t diff;
392     uint32_t wrap_diff;  /* how many ticks until we wrap? */
393     uint64_t cur_tick = hpet_get_ticks(t->state);
394 
395     /* whenever new timer is being set up, make sure wrap_flag is 0 */
396     t->wrap_flag = 0;
397     diff = hpet_calculate_diff(t, cur_tick);
398 
399     /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
400      * counter wraps in addition to an interrupt with comparator match.
401      */
402     if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
403         wrap_diff = 0xffffffff - (uint32_t)cur_tick;
404         if (wrap_diff < (uint32_t)diff) {
405             diff = wrap_diff;
406             t->wrap_flag = 1;
407         }
408     }
409     timer_mod(t->qemu_timer,
410                    qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
411 }
412 
413 static void hpet_del_timer(HPETTimer *t)
414 {
415     timer_del(t->qemu_timer);
416     update_irq(t, 0);
417 }
418 
419 #ifdef HPET_DEBUG
420 static uint32_t hpet_ram_readb(void *opaque, hwaddr addr)
421 {
422     printf("qemu: hpet_read b at %" PRIx64 "\n", addr);
423     return 0;
424 }
425 
426 static uint32_t hpet_ram_readw(void *opaque, hwaddr addr)
427 {
428     printf("qemu: hpet_read w at %" PRIx64 "\n", addr);
429     return 0;
430 }
431 #endif
432 
433 static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
434                               unsigned size)
435 {
436     HPETState *s = opaque;
437     uint64_t cur_tick, index;
438 
439     DPRINTF("qemu: Enter hpet_ram_readl at %" PRIx64 "\n", addr);
440     index = addr;
441     /*address range of all TN regs*/
442     if (index >= 0x100 && index <= 0x3ff) {
443         uint8_t timer_id = (addr - 0x100) / 0x20;
444         HPETTimer *timer = &s->timer[timer_id];
445 
446         if (timer_id > s->num_timers) {
447             DPRINTF("qemu: timer id out of range\n");
448             return 0;
449         }
450 
451         switch ((addr - 0x100) % 0x20) {
452         case HPET_TN_CFG:
453             return timer->config;
454         case HPET_TN_CFG + 4: // Interrupt capabilities
455             return timer->config >> 32;
456         case HPET_TN_CMP: // comparator register
457             return timer->cmp;
458         case HPET_TN_CMP + 4:
459             return timer->cmp >> 32;
460         case HPET_TN_ROUTE:
461             return timer->fsb;
462         case HPET_TN_ROUTE + 4:
463             return timer->fsb >> 32;
464         default:
465             DPRINTF("qemu: invalid hpet_ram_readl\n");
466             break;
467         }
468     } else {
469         switch (index) {
470         case HPET_ID:
471             return s->capability;
472         case HPET_PERIOD:
473             return s->capability >> 32;
474         case HPET_CFG:
475             return s->config;
476         case HPET_CFG + 4:
477             DPRINTF("qemu: invalid HPET_CFG + 4 hpet_ram_readl\n");
478             return 0;
479         case HPET_COUNTER:
480             if (hpet_enabled(s)) {
481                 cur_tick = hpet_get_ticks(s);
482             } else {
483                 cur_tick = s->hpet_counter;
484             }
485             DPRINTF("qemu: reading counter  = %" PRIx64 "\n", cur_tick);
486             return cur_tick;
487         case HPET_COUNTER + 4:
488             if (hpet_enabled(s)) {
489                 cur_tick = hpet_get_ticks(s);
490             } else {
491                 cur_tick = s->hpet_counter;
492             }
493             DPRINTF("qemu: reading counter + 4  = %" PRIx64 "\n", cur_tick);
494             return cur_tick >> 32;
495         case HPET_STATUS:
496             return s->isr;
497         default:
498             DPRINTF("qemu: invalid hpet_ram_readl\n");
499             break;
500         }
501     }
502     return 0;
503 }
504 
505 static void hpet_ram_write(void *opaque, hwaddr addr,
506                            uint64_t value, unsigned size)
507 {
508     int i;
509     HPETState *s = opaque;
510     uint64_t old_val, new_val, val, index;
511 
512     DPRINTF("qemu: Enter hpet_ram_writel at %" PRIx64 " = %#x\n", addr, value);
513     index = addr;
514     old_val = hpet_ram_read(opaque, addr, 4);
515     new_val = value;
516 
517     /*address range of all TN regs*/
518     if (index >= 0x100 && index <= 0x3ff) {
519         uint8_t timer_id = (addr - 0x100) / 0x20;
520         HPETTimer *timer = &s->timer[timer_id];
521 
522         DPRINTF("qemu: hpet_ram_writel timer_id = %#x\n", timer_id);
523         if (timer_id > s->num_timers) {
524             DPRINTF("qemu: timer id out of range\n");
525             return;
526         }
527         switch ((addr - 0x100) % 0x20) {
528         case HPET_TN_CFG:
529             DPRINTF("qemu: hpet_ram_writel HPET_TN_CFG\n");
530             if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
531                 update_irq(timer, 0);
532             }
533             val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
534             timer->config = (timer->config & 0xffffffff00000000ULL) | val;
535             if (new_val & HPET_TN_32BIT) {
536                 timer->cmp = (uint32_t)timer->cmp;
537                 timer->period = (uint32_t)timer->period;
538             }
539             if (activating_bit(old_val, new_val, HPET_TN_ENABLE) &&
540                 hpet_enabled(s)) {
541                 hpet_set_timer(timer);
542             } else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
543                 hpet_del_timer(timer);
544             }
545             break;
546         case HPET_TN_CFG + 4: // Interrupt capabilities
547             DPRINTF("qemu: invalid HPET_TN_CFG+4 write\n");
548             break;
549         case HPET_TN_CMP: // comparator register
550             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP\n");
551             if (timer->config & HPET_TN_32BIT) {
552                 new_val = (uint32_t)new_val;
553             }
554             if (!timer_is_periodic(timer)
555                 || (timer->config & HPET_TN_SETVAL)) {
556                 timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;
557             }
558             if (timer_is_periodic(timer)) {
559                 /*
560                  * FIXME: Clamp period to reasonable min value?
561                  * Clamp period to reasonable max value
562                  */
563                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
564                 timer->period =
565                     (timer->period & 0xffffffff00000000ULL) | new_val;
566             }
567             timer->config &= ~HPET_TN_SETVAL;
568             if (hpet_enabled(s)) {
569                 hpet_set_timer(timer);
570             }
571             break;
572         case HPET_TN_CMP + 4: // comparator register high order
573             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");
574             if (!timer_is_periodic(timer)
575                 || (timer->config & HPET_TN_SETVAL)) {
576                 timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;
577             } else {
578                 /*
579                  * FIXME: Clamp period to reasonable min value?
580                  * Clamp period to reasonable max value
581                  */
582                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
583                 timer->period =
584                     (timer->period & 0xffffffffULL) | new_val << 32;
585                 }
586                 timer->config &= ~HPET_TN_SETVAL;
587                 if (hpet_enabled(s)) {
588                     hpet_set_timer(timer);
589                 }
590                 break;
591         case HPET_TN_ROUTE:
592             timer->fsb = (timer->fsb & 0xffffffff00000000ULL) | new_val;
593             break;
594         case HPET_TN_ROUTE + 4:
595             timer->fsb = (new_val << 32) | (timer->fsb & 0xffffffff);
596             break;
597         default:
598             DPRINTF("qemu: invalid hpet_ram_writel\n");
599             break;
600         }
601         return;
602     } else {
603         switch (index) {
604         case HPET_ID:
605             return;
606         case HPET_CFG:
607             val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
608             s->config = (s->config & 0xffffffff00000000ULL) | val;
609             if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
610                 /* Enable main counter and interrupt generation. */
611                 s->hpet_offset =
612                     ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
613                 for (i = 0; i < s->num_timers; i++) {
614                     if ((&s->timer[i])->cmp != ~0ULL) {
615                         hpet_set_timer(&s->timer[i]);
616                     }
617                 }
618             } else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
619                 /* Halt main counter and disable interrupt generation. */
620                 s->hpet_counter = hpet_get_ticks(s);
621                 for (i = 0; i < s->num_timers; i++) {
622                     hpet_del_timer(&s->timer[i]);
623                 }
624             }
625             /* i8254 and RTC output pins are disabled
626              * when HPET is in legacy mode */
627             if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
628                 qemu_set_irq(s->pit_enabled, 0);
629                 qemu_irq_lower(s->irqs[0]);
630                 qemu_irq_lower(s->irqs[RTC_ISA_IRQ]);
631             } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
632                 qemu_irq_lower(s->irqs[0]);
633                 qemu_set_irq(s->pit_enabled, 1);
634                 qemu_set_irq(s->irqs[RTC_ISA_IRQ], s->rtc_irq_level);
635             }
636             break;
637         case HPET_CFG + 4:
638             DPRINTF("qemu: invalid HPET_CFG+4 write\n");
639             break;
640         case HPET_STATUS:
641             val = new_val & s->isr;
642             for (i = 0; i < s->num_timers; i++) {
643                 if (val & (1 << i)) {
644                     update_irq(&s->timer[i], 0);
645                 }
646             }
647             break;
648         case HPET_COUNTER:
649             if (hpet_enabled(s)) {
650                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
651             }
652             s->hpet_counter =
653                 (s->hpet_counter & 0xffffffff00000000ULL) | value;
654             DPRINTF("qemu: HPET counter written. ctr = %#x -> %" PRIx64 "\n",
655                     value, s->hpet_counter);
656             break;
657         case HPET_COUNTER + 4:
658             if (hpet_enabled(s)) {
659                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
660             }
661             s->hpet_counter =
662                 (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);
663             DPRINTF("qemu: HPET counter + 4 written. ctr = %#x -> %" PRIx64 "\n",
664                     value, s->hpet_counter);
665             break;
666         default:
667             DPRINTF("qemu: invalid hpet_ram_writel\n");
668             break;
669         }
670     }
671 }
672 
673 static const MemoryRegionOps hpet_ram_ops = {
674     .read = hpet_ram_read,
675     .write = hpet_ram_write,
676     .valid = {
677         .min_access_size = 4,
678         .max_access_size = 4,
679     },
680     .endianness = DEVICE_NATIVE_ENDIAN,
681 };
682 
683 static void hpet_reset(DeviceState *d)
684 {
685     HPETState *s = HPET(d);
686     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
687     int i;
688 
689     for (i = 0; i < s->num_timers; i++) {
690         HPETTimer *timer = &s->timer[i];
691 
692         hpet_del_timer(timer);
693         timer->cmp = ~0ULL;
694         timer->config = HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;
695         if (s->flags & (1 << HPET_MSI_SUPPORT)) {
696             timer->config |= HPET_TN_FSB_CAP;
697         }
698         /* advertise availability of ioapic int */
699         timer->config |=  (uint64_t)s->intcap << 32;
700         timer->period = 0ULL;
701         timer->wrap_flag = 0;
702     }
703 
704     qemu_set_irq(s->pit_enabled, 1);
705     s->hpet_counter = 0ULL;
706     s->hpet_offset = 0ULL;
707     s->config = 0ULL;
708     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
709     hpet_cfg.hpet[s->hpet_id].address = sbd->mmio[0].addr;
710 
711     /* to document that the RTC lowers its output on reset as well */
712     s->rtc_irq_level = 0;
713 }
714 
715 static void hpet_handle_legacy_irq(void *opaque, int n, int level)
716 {
717     HPETState *s = HPET(opaque);
718 
719     if (n == HPET_LEGACY_PIT_INT) {
720         if (!hpet_in_legacy_mode(s)) {
721             qemu_set_irq(s->irqs[0], level);
722         }
723     } else {
724         s->rtc_irq_level = level;
725         if (!hpet_in_legacy_mode(s)) {
726             qemu_set_irq(s->irqs[RTC_ISA_IRQ], level);
727         }
728     }
729 }
730 
731 static void hpet_init(Object *obj)
732 {
733     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
734     HPETState *s = HPET(obj);
735 
736     /* HPET Area */
737     memory_region_init_io(&s->iomem, obj, &hpet_ram_ops, s, "hpet", HPET_LEN);
738     sysbus_init_mmio(sbd, &s->iomem);
739 }
740 
741 static void hpet_realize(DeviceState *dev, Error **errp)
742 {
743     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
744     HPETState *s = HPET(dev);
745     int i;
746     HPETTimer *timer;
747 
748     if (!s->intcap) {
749         warn_report("Hpet's intcap not initialized");
750     }
751     if (hpet_cfg.count == UINT8_MAX) {
752         /* first instance */
753         hpet_cfg.count = 0;
754     }
755 
756     if (hpet_cfg.count == 8) {
757         error_setg(errp, "Only 8 instances of HPET is allowed");
758         return;
759     }
760 
761     s->hpet_id = hpet_cfg.count++;
762 
763     for (i = 0; i < HPET_NUM_IRQ_ROUTES; i++) {
764         sysbus_init_irq(sbd, &s->irqs[i]);
765     }
766 
767     if (s->num_timers < HPET_MIN_TIMERS) {
768         s->num_timers = HPET_MIN_TIMERS;
769     } else if (s->num_timers > HPET_MAX_TIMERS) {
770         s->num_timers = HPET_MAX_TIMERS;
771     }
772     for (i = 0; i < HPET_MAX_TIMERS; i++) {
773         timer = &s->timer[i];
774         timer->qemu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, hpet_timer, timer);
775         timer->tn = i;
776         timer->state = s;
777     }
778 
779     /* 64-bit main counter; LegacyReplacementRoute. */
780     s->capability = 0x8086a001ULL;
781     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
782     s->capability |= ((uint64_t)(HPET_CLK_PERIOD * FS_PER_NS) << 32);
783 
784     qdev_init_gpio_in(dev, hpet_handle_legacy_irq, 2);
785     qdev_init_gpio_out(dev, &s->pit_enabled, 1);
786 }
787 
788 static Property hpet_device_properties[] = {
789     DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
790     DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
791     DEFINE_PROP_UINT32(HPET_INTCAP, HPETState, intcap, 0),
792     DEFINE_PROP_BOOL("hpet-offset-saved", HPETState, hpet_offset_saved, true),
793     DEFINE_PROP_END_OF_LIST(),
794 };
795 
796 static void hpet_device_class_init(ObjectClass *klass, void *data)
797 {
798     DeviceClass *dc = DEVICE_CLASS(klass);
799 
800     dc->realize = hpet_realize;
801     dc->reset = hpet_reset;
802     dc->vmsd = &vmstate_hpet;
803     device_class_set_props(dc, hpet_device_properties);
804 }
805 
806 static const TypeInfo hpet_device_info = {
807     .name          = TYPE_HPET,
808     .parent        = TYPE_SYS_BUS_DEVICE,
809     .instance_size = sizeof(HPETState),
810     .instance_init = hpet_init,
811     .class_init    = hpet_device_class_init,
812 };
813 
814 static void hpet_register_types(void)
815 {
816     type_register_static(&hpet_device_info);
817 }
818 
819 type_init(hpet_register_types)
820