xref: /openbmc/qemu/hw/timer/hpet.c (revision 97841438)
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 "qapi/error.h"
31 #include "qemu/error-report.h"
32 #include "qemu/timer.h"
33 #include "hw/timer/hpet.h"
34 #include "hw/sysbus.h"
35 #include "hw/rtc/mc146818rtc.h"
36 #include "hw/rtc/mc146818rtc_regs.h"
37 #include "migration/vmstate.h"
38 #include "hw/timer/i8254.h"
39 #include "exec/address-spaces.h"
40 #include "qom/object.h"
41 
42 //#define HPET_DEBUG
43 #ifdef HPET_DEBUG
44 #define DPRINTF printf
45 #else
46 #define DPRINTF(...)
47 #endif
48 
49 #define HPET_MSI_SUPPORT        0
50 
51 OBJECT_DECLARE_SIMPLE_TYPE(HPETState, HPET)
52 
53 struct HPETState;
54 typedef struct HPETTimer {  /* timers */
55     uint8_t tn;             /*timer number*/
56     QEMUTimer *qemu_timer;
57     struct HPETState *state;
58     /* Memory-mapped, software visible timer registers */
59     uint64_t config;        /* configuration/cap */
60     uint64_t cmp;           /* comparator */
61     uint64_t fsb;           /* FSB route */
62     /* Hidden register state */
63     uint64_t period;        /* Last value written to comparator */
64     uint8_t wrap_flag;      /* timer pop will indicate wrap for one-shot 32-bit
65                              * mode. Next pop will be actual timer expiration.
66                              */
67 } HPETTimer;
68 
69 struct HPETState {
70     /*< private >*/
71     SysBusDevice parent_obj;
72     /*< public >*/
73 
74     MemoryRegion iomem;
75     uint64_t hpet_offset;
76     bool hpet_offset_saved;
77     qemu_irq irqs[HPET_NUM_IRQ_ROUTES];
78     uint32_t flags;
79     uint8_t rtc_irq_level;
80     qemu_irq pit_enabled;
81     uint8_t num_timers;
82     uint32_t intcap;
83     HPETTimer timer[HPET_MAX_TIMERS];
84 
85     /* Memory-mapped, software visible registers */
86     uint64_t capability;        /* capabilities */
87     uint64_t config;            /* configuration */
88     uint64_t isr;               /* interrupt status reg */
89     uint64_t hpet_counter;      /* main counter */
90     uint8_t  hpet_id;           /* instance id */
91 };
92 
93 static uint32_t hpet_in_legacy_mode(HPETState *s)
94 {
95     return s->config & HPET_CFG_LEGACY;
96 }
97 
98 static uint32_t timer_int_route(struct HPETTimer *timer)
99 {
100     return (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;
101 }
102 
103 static uint32_t timer_fsb_route(HPETTimer *t)
104 {
105     return t->config & HPET_TN_FSB_ENABLE;
106 }
107 
108 static uint32_t hpet_enabled(HPETState *s)
109 {
110     return s->config & HPET_CFG_ENABLE;
111 }
112 
113 static uint32_t timer_is_periodic(HPETTimer *t)
114 {
115     return t->config & HPET_TN_PERIODIC;
116 }
117 
118 static uint32_t timer_enabled(HPETTimer *t)
119 {
120     return t->config & HPET_TN_ENABLE;
121 }
122 
123 static uint32_t hpet_time_after(uint64_t a, uint64_t b)
124 {
125     return ((int32_t)(b - a) < 0);
126 }
127 
128 static uint32_t hpet_time_after64(uint64_t a, uint64_t b)
129 {
130     return ((int64_t)(b - a) < 0);
131 }
132 
133 static uint64_t ticks_to_ns(uint64_t value)
134 {
135     return value * HPET_CLK_PERIOD;
136 }
137 
138 static uint64_t ns_to_ticks(uint64_t value)
139 {
140     return value / HPET_CLK_PERIOD;
141 }
142 
143 static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)
144 {
145     new &= mask;
146     new |= old & ~mask;
147     return new;
148 }
149 
150 static int activating_bit(uint64_t old, uint64_t new, uint64_t mask)
151 {
152     return (!(old & mask) && (new & mask));
153 }
154 
155 static int deactivating_bit(uint64_t old, uint64_t new, uint64_t mask)
156 {
157     return ((old & mask) && !(new & mask));
158 }
159 
160 static uint64_t hpet_get_ticks(HPETState *s)
161 {
162     return ns_to_ticks(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->hpet_offset);
163 }
164 
165 /*
166  * calculate diff between comparator value and current ticks
167  */
168 static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
169 {
170 
171     if (t->config & HPET_TN_32BIT) {
172         uint32_t diff, cmp;
173 
174         cmp = (uint32_t)t->cmp;
175         diff = cmp - (uint32_t)current;
176         diff = (int32_t)diff > 0 ? diff : (uint32_t)1;
177         return (uint64_t)diff;
178     } else {
179         uint64_t diff, cmp;
180 
181         cmp = t->cmp;
182         diff = cmp - current;
183         diff = (int64_t)diff > 0 ? diff : (uint64_t)1;
184         return diff;
185     }
186 }
187 
188 static void update_irq(struct HPETTimer *timer, int set)
189 {
190     uint64_t mask;
191     HPETState *s;
192     int route;
193 
194     if (timer->tn <= 1 && hpet_in_legacy_mode(timer->state)) {
195         /* if LegacyReplacementRoute bit is set, HPET specification requires
196          * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
197          * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.
198          */
199         route = (timer->tn == 0) ? 0 : RTC_ISA_IRQ;
200     } else {
201         route = timer_int_route(timer);
202     }
203     s = timer->state;
204     mask = 1 << timer->tn;
205     if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
206         s->isr &= ~mask;
207         if (!timer_fsb_route(timer)) {
208             qemu_irq_lower(s->irqs[route]);
209         }
210     } else if (timer_fsb_route(timer)) {
211         address_space_stl_le(&address_space_memory, timer->fsb >> 32,
212                              timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
213                              NULL);
214     } else if (timer->config & HPET_TN_TYPE_LEVEL) {
215         s->isr |= mask;
216         qemu_irq_raise(s->irqs[route]);
217     } else {
218         s->isr &= ~mask;
219         qemu_irq_pulse(s->irqs[route]);
220     }
221 }
222 
223 static int hpet_pre_save(void *opaque)
224 {
225     HPETState *s = opaque;
226 
227     /* save current counter value */
228     if (hpet_enabled(s)) {
229         s->hpet_counter = hpet_get_ticks(s);
230     }
231 
232     return 0;
233 }
234 
235 static int hpet_pre_load(void *opaque)
236 {
237     HPETState *s = opaque;
238 
239     /* version 1 only supports 3, later versions will load the actual value */
240     s->num_timers = HPET_MIN_TIMERS;
241     return 0;
242 }
243 
244 static bool hpet_validate_num_timers(void *opaque, int version_id)
245 {
246     HPETState *s = opaque;
247 
248     if (s->num_timers < HPET_MIN_TIMERS) {
249         return false;
250     } else if (s->num_timers > HPET_MAX_TIMERS) {
251         return false;
252     }
253     return true;
254 }
255 
256 static int hpet_post_load(void *opaque, int version_id)
257 {
258     HPETState *s = opaque;
259 
260     /* Recalculate the offset between the main counter and guest time */
261     if (!s->hpet_offset_saved) {
262         s->hpet_offset = ticks_to_ns(s->hpet_counter)
263                         - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
264     }
265 
266     /* Push number of timers into capability returned via HPET_ID */
267     s->capability &= ~HPET_ID_NUM_TIM_MASK;
268     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
269     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
270 
271     /* Derive HPET_MSI_SUPPORT from the capability of the first timer. */
272     s->flags &= ~(1 << HPET_MSI_SUPPORT);
273     if (s->timer[0].config & HPET_TN_FSB_CAP) {
274         s->flags |= 1 << HPET_MSI_SUPPORT;
275     }
276     return 0;
277 }
278 
279 static bool hpet_offset_needed(void *opaque)
280 {
281     HPETState *s = opaque;
282 
283     return hpet_enabled(s) && s->hpet_offset_saved;
284 }
285 
286 static bool hpet_rtc_irq_level_needed(void *opaque)
287 {
288     HPETState *s = opaque;
289 
290     return s->rtc_irq_level != 0;
291 }
292 
293 static const VMStateDescription vmstate_hpet_rtc_irq_level = {
294     .name = "hpet/rtc_irq_level",
295     .version_id = 1,
296     .minimum_version_id = 1,
297     .needed = hpet_rtc_irq_level_needed,
298     .fields = (VMStateField[]) {
299         VMSTATE_UINT8(rtc_irq_level, HPETState),
300         VMSTATE_END_OF_LIST()
301     }
302 };
303 
304 static const VMStateDescription vmstate_hpet_offset = {
305     .name = "hpet/offset",
306     .version_id = 1,
307     .minimum_version_id = 1,
308     .needed = hpet_offset_needed,
309     .fields = (VMStateField[]) {
310         VMSTATE_UINT64(hpet_offset, HPETState),
311         VMSTATE_END_OF_LIST()
312     }
313 };
314 
315 static const VMStateDescription vmstate_hpet_timer = {
316     .name = "hpet_timer",
317     .version_id = 1,
318     .minimum_version_id = 1,
319     .fields = (VMStateField[]) {
320         VMSTATE_UINT8(tn, HPETTimer),
321         VMSTATE_UINT64(config, HPETTimer),
322         VMSTATE_UINT64(cmp, HPETTimer),
323         VMSTATE_UINT64(fsb, HPETTimer),
324         VMSTATE_UINT64(period, HPETTimer),
325         VMSTATE_UINT8(wrap_flag, HPETTimer),
326         VMSTATE_TIMER_PTR(qemu_timer, HPETTimer),
327         VMSTATE_END_OF_LIST()
328     }
329 };
330 
331 static const VMStateDescription vmstate_hpet = {
332     .name = "hpet",
333     .version_id = 2,
334     .minimum_version_id = 1,
335     .pre_save = hpet_pre_save,
336     .pre_load = hpet_pre_load,
337     .post_load = hpet_post_load,
338     .fields = (VMStateField[]) {
339         VMSTATE_UINT64(config, HPETState),
340         VMSTATE_UINT64(isr, HPETState),
341         VMSTATE_UINT64(hpet_counter, HPETState),
342         VMSTATE_UINT8_V(num_timers, HPETState, 2),
343         VMSTATE_VALIDATE("num_timers in range", hpet_validate_num_timers),
344         VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0,
345                                     vmstate_hpet_timer, HPETTimer),
346         VMSTATE_END_OF_LIST()
347     },
348     .subsections = (const VMStateDescription*[]) {
349         &vmstate_hpet_rtc_irq_level,
350         &vmstate_hpet_offset,
351         NULL
352     }
353 };
354 
355 /*
356  * timer expiration callback
357  */
358 static void hpet_timer(void *opaque)
359 {
360     HPETTimer *t = opaque;
361     uint64_t diff;
362 
363     uint64_t period = t->period;
364     uint64_t cur_tick = hpet_get_ticks(t->state);
365 
366     if (timer_is_periodic(t) && period != 0) {
367         if (t->config & HPET_TN_32BIT) {
368             while (hpet_time_after(cur_tick, t->cmp)) {
369                 t->cmp = (uint32_t)(t->cmp + t->period);
370             }
371         } else {
372             while (hpet_time_after64(cur_tick, t->cmp)) {
373                 t->cmp += period;
374             }
375         }
376         diff = hpet_calculate_diff(t, cur_tick);
377         timer_mod(t->qemu_timer,
378                        qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
379     } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
380         if (t->wrap_flag) {
381             diff = hpet_calculate_diff(t, cur_tick);
382             timer_mod(t->qemu_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
383                            (int64_t)ticks_to_ns(diff));
384             t->wrap_flag = 0;
385         }
386     }
387     update_irq(t, 1);
388 }
389 
390 static void hpet_set_timer(HPETTimer *t)
391 {
392     uint64_t diff;
393     uint32_t wrap_diff;  /* how many ticks until we wrap? */
394     uint64_t cur_tick = hpet_get_ticks(t->state);
395 
396     /* whenever new timer is being set up, make sure wrap_flag is 0 */
397     t->wrap_flag = 0;
398     diff = hpet_calculate_diff(t, cur_tick);
399 
400     /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
401      * counter wraps in addition to an interrupt with comparator match.
402      */
403     if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
404         wrap_diff = 0xffffffff - (uint32_t)cur_tick;
405         if (wrap_diff < (uint32_t)diff) {
406             diff = wrap_diff;
407             t->wrap_flag = 1;
408         }
409     }
410     timer_mod(t->qemu_timer,
411                    qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
412 }
413 
414 static void hpet_del_timer(HPETTimer *t)
415 {
416     timer_del(t->qemu_timer);
417     update_irq(t, 0);
418 }
419 
420 static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
421                               unsigned size)
422 {
423     HPETState *s = opaque;
424     uint64_t cur_tick, index;
425 
426     DPRINTF("qemu: Enter hpet_ram_readl at %" PRIx64 "\n", addr);
427     index = addr;
428     /*address range of all TN regs*/
429     if (index >= 0x100 && index <= 0x3ff) {
430         uint8_t timer_id = (addr - 0x100) / 0x20;
431         HPETTimer *timer = &s->timer[timer_id];
432 
433         if (timer_id > s->num_timers) {
434             DPRINTF("qemu: timer id out of range\n");
435             return 0;
436         }
437 
438         switch ((addr - 0x100) % 0x20) {
439         case HPET_TN_CFG:
440             return timer->config;
441         case HPET_TN_CFG + 4: // Interrupt capabilities
442             return timer->config >> 32;
443         case HPET_TN_CMP: // comparator register
444             return timer->cmp;
445         case HPET_TN_CMP + 4:
446             return timer->cmp >> 32;
447         case HPET_TN_ROUTE:
448             return timer->fsb;
449         case HPET_TN_ROUTE + 4:
450             return timer->fsb >> 32;
451         default:
452             DPRINTF("qemu: invalid hpet_ram_readl\n");
453             break;
454         }
455     } else {
456         switch (index) {
457         case HPET_ID:
458             return s->capability;
459         case HPET_PERIOD:
460             return s->capability >> 32;
461         case HPET_CFG:
462             return s->config;
463         case HPET_CFG + 4:
464             DPRINTF("qemu: invalid HPET_CFG + 4 hpet_ram_readl\n");
465             return 0;
466         case HPET_COUNTER:
467             if (hpet_enabled(s)) {
468                 cur_tick = hpet_get_ticks(s);
469             } else {
470                 cur_tick = s->hpet_counter;
471             }
472             DPRINTF("qemu: reading counter  = %" PRIx64 "\n", cur_tick);
473             return cur_tick;
474         case HPET_COUNTER + 4:
475             if (hpet_enabled(s)) {
476                 cur_tick = hpet_get_ticks(s);
477             } else {
478                 cur_tick = s->hpet_counter;
479             }
480             DPRINTF("qemu: reading counter + 4  = %" PRIx64 "\n", cur_tick);
481             return cur_tick >> 32;
482         case HPET_STATUS:
483             return s->isr;
484         default:
485             DPRINTF("qemu: invalid hpet_ram_readl\n");
486             break;
487         }
488     }
489     return 0;
490 }
491 
492 static void hpet_ram_write(void *opaque, hwaddr addr,
493                            uint64_t value, unsigned size)
494 {
495     int i;
496     HPETState *s = opaque;
497     uint64_t old_val, new_val, val, index;
498 
499     DPRINTF("qemu: Enter hpet_ram_writel at %" PRIx64 " = 0x%" PRIx64 "\n",
500             addr, value);
501     index = addr;
502     old_val = hpet_ram_read(opaque, addr, 4);
503     new_val = value;
504 
505     /*address range of all TN regs*/
506     if (index >= 0x100 && index <= 0x3ff) {
507         uint8_t timer_id = (addr - 0x100) / 0x20;
508         HPETTimer *timer = &s->timer[timer_id];
509 
510         DPRINTF("qemu: hpet_ram_writel timer_id = 0x%x\n", timer_id);
511         if (timer_id > s->num_timers) {
512             DPRINTF("qemu: timer id out of range\n");
513             return;
514         }
515         switch ((addr - 0x100) % 0x20) {
516         case HPET_TN_CFG:
517             DPRINTF("qemu: hpet_ram_writel HPET_TN_CFG\n");
518             if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
519                 update_irq(timer, 0);
520             }
521             val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
522             timer->config = (timer->config & 0xffffffff00000000ULL) | val;
523             if (new_val & HPET_TN_32BIT) {
524                 timer->cmp = (uint32_t)timer->cmp;
525                 timer->period = (uint32_t)timer->period;
526             }
527             if (activating_bit(old_val, new_val, HPET_TN_ENABLE) &&
528                 hpet_enabled(s)) {
529                 hpet_set_timer(timer);
530             } else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
531                 hpet_del_timer(timer);
532             }
533             break;
534         case HPET_TN_CFG + 4: // Interrupt capabilities
535             DPRINTF("qemu: invalid HPET_TN_CFG+4 write\n");
536             break;
537         case HPET_TN_CMP: // comparator register
538             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP\n");
539             if (timer->config & HPET_TN_32BIT) {
540                 new_val = (uint32_t)new_val;
541             }
542             if (!timer_is_periodic(timer)
543                 || (timer->config & HPET_TN_SETVAL)) {
544                 timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;
545             }
546             if (timer_is_periodic(timer)) {
547                 /*
548                  * FIXME: Clamp period to reasonable min value?
549                  * Clamp period to reasonable max value
550                  */
551                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
552                 timer->period =
553                     (timer->period & 0xffffffff00000000ULL) | new_val;
554             }
555             timer->config &= ~HPET_TN_SETVAL;
556             if (hpet_enabled(s)) {
557                 hpet_set_timer(timer);
558             }
559             break;
560         case HPET_TN_CMP + 4: // comparator register high order
561             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");
562             if (!timer_is_periodic(timer)
563                 || (timer->config & HPET_TN_SETVAL)) {
564                 timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;
565             } else {
566                 /*
567                  * FIXME: Clamp period to reasonable min value?
568                  * Clamp period to reasonable max value
569                  */
570                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
571                 timer->period =
572                     (timer->period & 0xffffffffULL) | new_val << 32;
573                 }
574                 timer->config &= ~HPET_TN_SETVAL;
575                 if (hpet_enabled(s)) {
576                     hpet_set_timer(timer);
577                 }
578                 break;
579         case HPET_TN_ROUTE:
580             timer->fsb = (timer->fsb & 0xffffffff00000000ULL) | new_val;
581             break;
582         case HPET_TN_ROUTE + 4:
583             timer->fsb = (new_val << 32) | (timer->fsb & 0xffffffff);
584             break;
585         default:
586             DPRINTF("qemu: invalid hpet_ram_writel\n");
587             break;
588         }
589         return;
590     } else {
591         switch (index) {
592         case HPET_ID:
593             return;
594         case HPET_CFG:
595             val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
596             s->config = (s->config & 0xffffffff00000000ULL) | val;
597             if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
598                 /* Enable main counter and interrupt generation. */
599                 s->hpet_offset =
600                     ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
601                 for (i = 0; i < s->num_timers; i++) {
602                     if ((&s->timer[i])->cmp != ~0ULL) {
603                         hpet_set_timer(&s->timer[i]);
604                     }
605                 }
606             } else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
607                 /* Halt main counter and disable interrupt generation. */
608                 s->hpet_counter = hpet_get_ticks(s);
609                 for (i = 0; i < s->num_timers; i++) {
610                     hpet_del_timer(&s->timer[i]);
611                 }
612             }
613             /* i8254 and RTC output pins are disabled
614              * when HPET is in legacy mode */
615             if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
616                 qemu_set_irq(s->pit_enabled, 0);
617                 qemu_irq_lower(s->irqs[0]);
618                 qemu_irq_lower(s->irqs[RTC_ISA_IRQ]);
619             } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
620                 qemu_irq_lower(s->irqs[0]);
621                 qemu_set_irq(s->pit_enabled, 1);
622                 qemu_set_irq(s->irqs[RTC_ISA_IRQ], s->rtc_irq_level);
623             }
624             break;
625         case HPET_CFG + 4:
626             DPRINTF("qemu: invalid HPET_CFG+4 write\n");
627             break;
628         case HPET_STATUS:
629             val = new_val & s->isr;
630             for (i = 0; i < s->num_timers; i++) {
631                 if (val & (1 << i)) {
632                     update_irq(&s->timer[i], 0);
633                 }
634             }
635             break;
636         case HPET_COUNTER:
637             if (hpet_enabled(s)) {
638                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
639             }
640             s->hpet_counter =
641                 (s->hpet_counter & 0xffffffff00000000ULL) | value;
642             DPRINTF("qemu: HPET counter written. ctr = 0x%" PRIx64 " -> "
643                     "%" PRIx64 "\n", value, s->hpet_counter);
644             break;
645         case HPET_COUNTER + 4:
646             if (hpet_enabled(s)) {
647                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
648             }
649             s->hpet_counter =
650                 (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);
651             DPRINTF("qemu: HPET counter + 4 written. ctr = 0x%" PRIx64 " -> "
652                     "%" PRIx64 "\n", value, s->hpet_counter);
653             break;
654         default:
655             DPRINTF("qemu: invalid hpet_ram_writel\n");
656             break;
657         }
658     }
659 }
660 
661 static const MemoryRegionOps hpet_ram_ops = {
662     .read = hpet_ram_read,
663     .write = hpet_ram_write,
664     .valid = {
665         .min_access_size = 4,
666         .max_access_size = 4,
667     },
668     .endianness = DEVICE_NATIVE_ENDIAN,
669 };
670 
671 static void hpet_reset(DeviceState *d)
672 {
673     HPETState *s = HPET(d);
674     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
675     int i;
676 
677     for (i = 0; i < s->num_timers; i++) {
678         HPETTimer *timer = &s->timer[i];
679 
680         hpet_del_timer(timer);
681         timer->cmp = ~0ULL;
682         timer->config = HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;
683         if (s->flags & (1 << HPET_MSI_SUPPORT)) {
684             timer->config |= HPET_TN_FSB_CAP;
685         }
686         /* advertise availability of ioapic int */
687         timer->config |=  (uint64_t)s->intcap << 32;
688         timer->period = 0ULL;
689         timer->wrap_flag = 0;
690     }
691 
692     qemu_set_irq(s->pit_enabled, 1);
693     s->hpet_counter = 0ULL;
694     s->hpet_offset = 0ULL;
695     s->config = 0ULL;
696     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
697     hpet_cfg.hpet[s->hpet_id].address = sbd->mmio[0].addr;
698 
699     /* to document that the RTC lowers its output on reset as well */
700     s->rtc_irq_level = 0;
701 }
702 
703 static void hpet_handle_legacy_irq(void *opaque, int n, int level)
704 {
705     HPETState *s = HPET(opaque);
706 
707     if (n == HPET_LEGACY_PIT_INT) {
708         if (!hpet_in_legacy_mode(s)) {
709             qemu_set_irq(s->irqs[0], level);
710         }
711     } else {
712         s->rtc_irq_level = level;
713         if (!hpet_in_legacy_mode(s)) {
714             qemu_set_irq(s->irqs[RTC_ISA_IRQ], level);
715         }
716     }
717 }
718 
719 static void hpet_init(Object *obj)
720 {
721     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
722     HPETState *s = HPET(obj);
723 
724     /* HPET Area */
725     memory_region_init_io(&s->iomem, obj, &hpet_ram_ops, s, "hpet", HPET_LEN);
726     sysbus_init_mmio(sbd, &s->iomem);
727 }
728 
729 static void hpet_realize(DeviceState *dev, Error **errp)
730 {
731     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
732     HPETState *s = HPET(dev);
733     int i;
734     HPETTimer *timer;
735 
736     if (!s->intcap) {
737         warn_report("Hpet's intcap not initialized");
738     }
739     if (hpet_cfg.count == UINT8_MAX) {
740         /* first instance */
741         hpet_cfg.count = 0;
742     }
743 
744     if (hpet_cfg.count == 8) {
745         error_setg(errp, "Only 8 instances of HPET is allowed");
746         return;
747     }
748 
749     s->hpet_id = hpet_cfg.count++;
750 
751     for (i = 0; i < HPET_NUM_IRQ_ROUTES; i++) {
752         sysbus_init_irq(sbd, &s->irqs[i]);
753     }
754 
755     if (s->num_timers < HPET_MIN_TIMERS) {
756         s->num_timers = HPET_MIN_TIMERS;
757     } else if (s->num_timers > HPET_MAX_TIMERS) {
758         s->num_timers = HPET_MAX_TIMERS;
759     }
760     for (i = 0; i < HPET_MAX_TIMERS; i++) {
761         timer = &s->timer[i];
762         timer->qemu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, hpet_timer, timer);
763         timer->tn = i;
764         timer->state = s;
765     }
766 
767     /* 64-bit main counter; LegacyReplacementRoute. */
768     s->capability = 0x8086a001ULL;
769     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
770     s->capability |= ((uint64_t)(HPET_CLK_PERIOD * FS_PER_NS) << 32);
771 
772     qdev_init_gpio_in(dev, hpet_handle_legacy_irq, 2);
773     qdev_init_gpio_out(dev, &s->pit_enabled, 1);
774 }
775 
776 static Property hpet_device_properties[] = {
777     DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
778     DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
779     DEFINE_PROP_UINT32(HPET_INTCAP, HPETState, intcap, 0),
780     DEFINE_PROP_BOOL("hpet-offset-saved", HPETState, hpet_offset_saved, true),
781     DEFINE_PROP_END_OF_LIST(),
782 };
783 
784 static void hpet_device_class_init(ObjectClass *klass, void *data)
785 {
786     DeviceClass *dc = DEVICE_CLASS(klass);
787 
788     dc->realize = hpet_realize;
789     dc->reset = hpet_reset;
790     dc->vmsd = &vmstate_hpet;
791     device_class_set_props(dc, hpet_device_properties);
792 }
793 
794 static const TypeInfo hpet_device_info = {
795     .name          = TYPE_HPET,
796     .parent        = TYPE_SYS_BUS_DEVICE,
797     .instance_size = sizeof(HPETState),
798     .instance_init = hpet_init,
799     .class_init    = hpet_device_class_init,
800 };
801 
802 static void hpet_register_types(void)
803 {
804     type_register_static(&hpet_device_info);
805 }
806 
807 type_init(hpet_register_types)
808