xref: /openbmc/qemu/hw/timer/hpet.c (revision c16de0d9)
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 
43 //#define HPET_DEBUG
44 #ifdef HPET_DEBUG
45 #define DPRINTF printf
46 #else
47 #define DPRINTF(...)
48 #endif
49 
50 #define HPET_MSI_SUPPORT        0
51 
52 OBJECT_DECLARE_SIMPLE_TYPE(HPETState, HPET)
53 
54 struct HPETState;
55 typedef struct HPETTimer {  /* timers */
56     uint8_t tn;             /*timer number*/
57     QEMUTimer *qemu_timer;
58     struct HPETState *state;
59     /* Memory-mapped, software visible timer registers */
60     uint64_t config;        /* configuration/cap */
61     uint64_t cmp;           /* comparator */
62     uint64_t fsb;           /* FSB route */
63     /* Hidden register state */
64     uint64_t period;        /* Last value written to comparator */
65     uint8_t wrap_flag;      /* timer pop will indicate wrap for one-shot 32-bit
66                              * mode. Next pop will be actual timer expiration.
67                              */
68 } HPETTimer;
69 
70 struct HPETState {
71     /*< private >*/
72     SysBusDevice parent_obj;
73     /*< public >*/
74 
75     MemoryRegion iomem;
76     uint64_t hpet_offset;
77     bool hpet_offset_saved;
78     qemu_irq irqs[HPET_NUM_IRQ_ROUTES];
79     uint32_t flags;
80     uint8_t rtc_irq_level;
81     qemu_irq pit_enabled;
82     uint8_t num_timers;
83     uint32_t intcap;
84     HPETTimer timer[HPET_MAX_TIMERS];
85 
86     /* Memory-mapped, software visible registers */
87     uint64_t capability;        /* capabilities */
88     uint64_t config;            /* configuration */
89     uint64_t isr;               /* interrupt status reg */
90     uint64_t hpet_counter;      /* main counter */
91     uint8_t  hpet_id;           /* instance id */
92 };
93 
94 static uint32_t hpet_in_legacy_mode(HPETState *s)
95 {
96     return s->config & HPET_CFG_LEGACY;
97 }
98 
99 static uint32_t timer_int_route(struct HPETTimer *timer)
100 {
101     return (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;
102 }
103 
104 static uint32_t timer_fsb_route(HPETTimer *t)
105 {
106     return t->config & HPET_TN_FSB_ENABLE;
107 }
108 
109 static uint32_t hpet_enabled(HPETState *s)
110 {
111     return s->config & HPET_CFG_ENABLE;
112 }
113 
114 static uint32_t timer_is_periodic(HPETTimer *t)
115 {
116     return t->config & HPET_TN_PERIODIC;
117 }
118 
119 static uint32_t timer_enabled(HPETTimer *t)
120 {
121     return t->config & HPET_TN_ENABLE;
122 }
123 
124 static uint32_t hpet_time_after(uint64_t a, uint64_t b)
125 {
126     return ((int32_t)(b - a) < 0);
127 }
128 
129 static uint32_t hpet_time_after64(uint64_t a, uint64_t b)
130 {
131     return ((int64_t)(b - a) < 0);
132 }
133 
134 static uint64_t ticks_to_ns(uint64_t value)
135 {
136     return value * HPET_CLK_PERIOD;
137 }
138 
139 static uint64_t ns_to_ticks(uint64_t value)
140 {
141     return value / HPET_CLK_PERIOD;
142 }
143 
144 static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)
145 {
146     new &= mask;
147     new |= old & ~mask;
148     return new;
149 }
150 
151 static int activating_bit(uint64_t old, uint64_t new, uint64_t mask)
152 {
153     return (!(old & mask) && (new & mask));
154 }
155 
156 static int deactivating_bit(uint64_t old, uint64_t new, uint64_t mask)
157 {
158     return ((old & mask) && !(new & mask));
159 }
160 
161 static uint64_t hpet_get_ticks(HPETState *s)
162 {
163     return ns_to_ticks(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->hpet_offset);
164 }
165 
166 /*
167  * calculate diff between comparator value and current ticks
168  */
169 static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
170 {
171 
172     if (t->config & HPET_TN_32BIT) {
173         uint32_t diff, cmp;
174 
175         cmp = (uint32_t)t->cmp;
176         diff = cmp - (uint32_t)current;
177         diff = (int32_t)diff > 0 ? diff : (uint32_t)1;
178         return (uint64_t)diff;
179     } else {
180         uint64_t diff, cmp;
181 
182         cmp = t->cmp;
183         diff = cmp - current;
184         diff = (int64_t)diff > 0 ? diff : (uint64_t)1;
185         return diff;
186     }
187 }
188 
189 static void update_irq(struct HPETTimer *timer, int set)
190 {
191     uint64_t mask;
192     HPETState *s;
193     int route;
194 
195     if (timer->tn <= 1 && hpet_in_legacy_mode(timer->state)) {
196         /* if LegacyReplacementRoute bit is set, HPET specification requires
197          * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
198          * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.
199          */
200         route = (timer->tn == 0) ? 0 : RTC_ISA_IRQ;
201     } else {
202         route = timer_int_route(timer);
203     }
204     s = timer->state;
205     mask = 1 << timer->tn;
206     if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
207         s->isr &= ~mask;
208         if (!timer_fsb_route(timer)) {
209             qemu_irq_lower(s->irqs[route]);
210         }
211     } else if (timer_fsb_route(timer)) {
212         address_space_stl_le(&address_space_memory, timer->fsb >> 32,
213                              timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
214                              NULL);
215     } else if (timer->config & HPET_TN_TYPE_LEVEL) {
216         s->isr |= mask;
217         qemu_irq_raise(s->irqs[route]);
218     } else {
219         s->isr &= ~mask;
220         qemu_irq_pulse(s->irqs[route]);
221     }
222 }
223 
224 static int hpet_pre_save(void *opaque)
225 {
226     HPETState *s = opaque;
227 
228     /* save current counter value */
229     if (hpet_enabled(s)) {
230         s->hpet_counter = hpet_get_ticks(s);
231     }
232 
233     return 0;
234 }
235 
236 static int hpet_pre_load(void *opaque)
237 {
238     HPETState *s = opaque;
239 
240     /* version 1 only supports 3, later versions will load the actual value */
241     s->num_timers = HPET_MIN_TIMERS;
242     return 0;
243 }
244 
245 static bool hpet_validate_num_timers(void *opaque, int version_id)
246 {
247     HPETState *s = opaque;
248 
249     if (s->num_timers < HPET_MIN_TIMERS) {
250         return false;
251     } else if (s->num_timers > HPET_MAX_TIMERS) {
252         return false;
253     }
254     return true;
255 }
256 
257 static int hpet_post_load(void *opaque, int version_id)
258 {
259     HPETState *s = opaque;
260 
261     /* Recalculate the offset between the main counter and guest time */
262     if (!s->hpet_offset_saved) {
263         s->hpet_offset = ticks_to_ns(s->hpet_counter)
264                         - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
265     }
266 
267     /* Push number of timers into capability returned via HPET_ID */
268     s->capability &= ~HPET_ID_NUM_TIM_MASK;
269     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
270     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
271 
272     /* Derive HPET_MSI_SUPPORT from the capability of the first timer. */
273     s->flags &= ~(1 << HPET_MSI_SUPPORT);
274     if (s->timer[0].config & HPET_TN_FSB_CAP) {
275         s->flags |= 1 << HPET_MSI_SUPPORT;
276     }
277     return 0;
278 }
279 
280 static bool hpet_offset_needed(void *opaque)
281 {
282     HPETState *s = opaque;
283 
284     return hpet_enabled(s) && s->hpet_offset_saved;
285 }
286 
287 static bool hpet_rtc_irq_level_needed(void *opaque)
288 {
289     HPETState *s = opaque;
290 
291     return s->rtc_irq_level != 0;
292 }
293 
294 static const VMStateDescription vmstate_hpet_rtc_irq_level = {
295     .name = "hpet/rtc_irq_level",
296     .version_id = 1,
297     .minimum_version_id = 1,
298     .needed = hpet_rtc_irq_level_needed,
299     .fields = (const VMStateField[]) {
300         VMSTATE_UINT8(rtc_irq_level, HPETState),
301         VMSTATE_END_OF_LIST()
302     }
303 };
304 
305 static const VMStateDescription vmstate_hpet_offset = {
306     .name = "hpet/offset",
307     .version_id = 1,
308     .minimum_version_id = 1,
309     .needed = hpet_offset_needed,
310     .fields = (const VMStateField[]) {
311         VMSTATE_UINT64(hpet_offset, HPETState),
312         VMSTATE_END_OF_LIST()
313     }
314 };
315 
316 static const VMStateDescription vmstate_hpet_timer = {
317     .name = "hpet_timer",
318     .version_id = 1,
319     .minimum_version_id = 1,
320     .fields = (const VMStateField[]) {
321         VMSTATE_UINT8(tn, HPETTimer),
322         VMSTATE_UINT64(config, HPETTimer),
323         VMSTATE_UINT64(cmp, HPETTimer),
324         VMSTATE_UINT64(fsb, HPETTimer),
325         VMSTATE_UINT64(period, HPETTimer),
326         VMSTATE_UINT8(wrap_flag, HPETTimer),
327         VMSTATE_TIMER_PTR(qemu_timer, HPETTimer),
328         VMSTATE_END_OF_LIST()
329     }
330 };
331 
332 static const VMStateDescription vmstate_hpet = {
333     .name = "hpet",
334     .version_id = 2,
335     .minimum_version_id = 1,
336     .pre_save = hpet_pre_save,
337     .pre_load = hpet_pre_load,
338     .post_load = hpet_post_load,
339     .fields = (const VMStateField[]) {
340         VMSTATE_UINT64(config, HPETState),
341         VMSTATE_UINT64(isr, HPETState),
342         VMSTATE_UINT64(hpet_counter, HPETState),
343         VMSTATE_UINT8_V(num_timers, HPETState, 2),
344         VMSTATE_VALIDATE("num_timers in range", hpet_validate_num_timers),
345         VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0,
346                                     vmstate_hpet_timer, HPETTimer),
347         VMSTATE_END_OF_LIST()
348     },
349     .subsections = (const VMStateDescription * const []) {
350         &vmstate_hpet_rtc_irq_level,
351         &vmstate_hpet_offset,
352         NULL
353     }
354 };
355 
356 static void hpet_arm(HPETTimer *t, uint64_t ticks)
357 {
358     if (ticks < ns_to_ticks(INT64_MAX / 2)) {
359         timer_mod(t->qemu_timer,
360                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ticks_to_ns(ticks));
361     } else {
362         timer_del(t->qemu_timer);
363     }
364 }
365 
366 /*
367  * timer expiration callback
368  */
369 static void hpet_timer(void *opaque)
370 {
371     HPETTimer *t = opaque;
372     uint64_t diff;
373 
374     uint64_t period = t->period;
375     uint64_t cur_tick = hpet_get_ticks(t->state);
376 
377     if (timer_is_periodic(t) && period != 0) {
378         if (t->config & HPET_TN_32BIT) {
379             while (hpet_time_after(cur_tick, t->cmp)) {
380                 t->cmp = (uint32_t)(t->cmp + t->period);
381             }
382         } else {
383             while (hpet_time_after64(cur_tick, t->cmp)) {
384                 t->cmp += period;
385             }
386         }
387         diff = hpet_calculate_diff(t, cur_tick);
388         hpet_arm(t, diff);
389     } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
390         if (t->wrap_flag) {
391             diff = hpet_calculate_diff(t, cur_tick);
392             hpet_arm(t, diff);
393             t->wrap_flag = 0;
394         }
395     }
396     update_irq(t, 1);
397 }
398 
399 static void hpet_set_timer(HPETTimer *t)
400 {
401     uint64_t diff;
402     uint32_t wrap_diff;  /* how many ticks until we wrap? */
403     uint64_t cur_tick = hpet_get_ticks(t->state);
404 
405     /* whenever new timer is being set up, make sure wrap_flag is 0 */
406     t->wrap_flag = 0;
407     diff = hpet_calculate_diff(t, cur_tick);
408 
409     /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
410      * counter wraps in addition to an interrupt with comparator match.
411      */
412     if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
413         wrap_diff = 0xffffffff - (uint32_t)cur_tick;
414         if (wrap_diff < (uint32_t)diff) {
415             diff = wrap_diff;
416             t->wrap_flag = 1;
417         }
418     }
419     hpet_arm(t, diff);
420 }
421 
422 static void hpet_del_timer(HPETTimer *t)
423 {
424     timer_del(t->qemu_timer);
425     update_irq(t, 0);
426 }
427 
428 static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
429                               unsigned size)
430 {
431     HPETState *s = opaque;
432     uint64_t cur_tick, index;
433 
434     DPRINTF("qemu: Enter hpet_ram_readl at %" PRIx64 "\n", addr);
435     index = addr;
436     /*address range of all TN regs*/
437     if (index >= 0x100 && index <= 0x3ff) {
438         uint8_t timer_id = (addr - 0x100) / 0x20;
439         HPETTimer *timer = &s->timer[timer_id];
440 
441         if (timer_id > s->num_timers) {
442             DPRINTF("qemu: timer id out of range\n");
443             return 0;
444         }
445 
446         switch ((addr - 0x100) % 0x20) {
447         case HPET_TN_CFG:
448             return timer->config;
449         case HPET_TN_CFG + 4: // Interrupt capabilities
450             return timer->config >> 32;
451         case HPET_TN_CMP: // comparator register
452             return timer->cmp;
453         case HPET_TN_CMP + 4:
454             return timer->cmp >> 32;
455         case HPET_TN_ROUTE:
456             return timer->fsb;
457         case HPET_TN_ROUTE + 4:
458             return timer->fsb >> 32;
459         default:
460             DPRINTF("qemu: invalid hpet_ram_readl\n");
461             break;
462         }
463     } else {
464         switch (index) {
465         case HPET_ID:
466             return s->capability;
467         case HPET_PERIOD:
468             return s->capability >> 32;
469         case HPET_CFG:
470             return s->config;
471         case HPET_CFG + 4:
472             DPRINTF("qemu: invalid HPET_CFG + 4 hpet_ram_readl\n");
473             return 0;
474         case HPET_COUNTER:
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  = %" PRIx64 "\n", cur_tick);
481             return cur_tick;
482         case HPET_COUNTER + 4:
483             if (hpet_enabled(s)) {
484                 cur_tick = hpet_get_ticks(s);
485             } else {
486                 cur_tick = s->hpet_counter;
487             }
488             DPRINTF("qemu: reading counter + 4  = %" PRIx64 "\n", cur_tick);
489             return cur_tick >> 32;
490         case HPET_STATUS:
491             return s->isr;
492         default:
493             DPRINTF("qemu: invalid hpet_ram_readl\n");
494             break;
495         }
496     }
497     return 0;
498 }
499 
500 static void hpet_ram_write(void *opaque, hwaddr addr,
501                            uint64_t value, unsigned size)
502 {
503     int i;
504     HPETState *s = opaque;
505     uint64_t old_val, new_val, val, index;
506 
507     DPRINTF("qemu: Enter hpet_ram_writel at %" PRIx64 " = 0x%" PRIx64 "\n",
508             addr, value);
509     index = addr;
510     old_val = hpet_ram_read(opaque, addr, 4);
511     new_val = value;
512 
513     /*address range of all TN regs*/
514     if (index >= 0x100 && index <= 0x3ff) {
515         uint8_t timer_id = (addr - 0x100) / 0x20;
516         HPETTimer *timer = &s->timer[timer_id];
517 
518         DPRINTF("qemu: hpet_ram_writel timer_id = 0x%x\n", timer_id);
519         if (timer_id > s->num_timers) {
520             DPRINTF("qemu: timer id out of range\n");
521             return;
522         }
523         switch ((addr - 0x100) % 0x20) {
524         case HPET_TN_CFG:
525             DPRINTF("qemu: hpet_ram_writel HPET_TN_CFG\n");
526             if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
527                 update_irq(timer, 0);
528             }
529             val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
530             timer->config = (timer->config & 0xffffffff00000000ULL) | val;
531             if (new_val & HPET_TN_32BIT) {
532                 timer->cmp = (uint32_t)timer->cmp;
533                 timer->period = (uint32_t)timer->period;
534             }
535             if (activating_bit(old_val, new_val, HPET_TN_ENABLE) &&
536                 hpet_enabled(s)) {
537                 hpet_set_timer(timer);
538             } else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
539                 hpet_del_timer(timer);
540             }
541             break;
542         case HPET_TN_CFG + 4: // Interrupt capabilities
543             DPRINTF("qemu: invalid HPET_TN_CFG+4 write\n");
544             break;
545         case HPET_TN_CMP: // comparator register
546             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP\n");
547             if (timer->config & HPET_TN_32BIT) {
548                 new_val = (uint32_t)new_val;
549             }
550             if (!timer_is_periodic(timer)
551                 || (timer->config & HPET_TN_SETVAL)) {
552                 timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;
553             }
554             if (timer_is_periodic(timer)) {
555                 /*
556                  * FIXME: Clamp period to reasonable min value?
557                  * Clamp period to reasonable max value
558                  */
559                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
560                 timer->period =
561                     (timer->period & 0xffffffff00000000ULL) | new_val;
562             }
563             timer->config &= ~HPET_TN_SETVAL;
564             if (hpet_enabled(s)) {
565                 hpet_set_timer(timer);
566             }
567             break;
568         case HPET_TN_CMP + 4: // comparator register high order
569             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");
570             if (!timer_is_periodic(timer)
571                 || (timer->config & HPET_TN_SETVAL)) {
572                 timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;
573             } else {
574                 /*
575                  * FIXME: Clamp period to reasonable min value?
576                  * Clamp period to reasonable max value
577                  */
578                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
579                 timer->period =
580                     (timer->period & 0xffffffffULL) | new_val << 32;
581                 }
582                 timer->config &= ~HPET_TN_SETVAL;
583                 if (hpet_enabled(s)) {
584                     hpet_set_timer(timer);
585                 }
586                 break;
587         case HPET_TN_ROUTE:
588             timer->fsb = (timer->fsb & 0xffffffff00000000ULL) | new_val;
589             break;
590         case HPET_TN_ROUTE + 4:
591             timer->fsb = (new_val << 32) | (timer->fsb & 0xffffffff);
592             break;
593         default:
594             DPRINTF("qemu: invalid hpet_ram_writel\n");
595             break;
596         }
597         return;
598     } else {
599         switch (index) {
600         case HPET_ID:
601             return;
602         case HPET_CFG:
603             val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
604             s->config = (s->config & 0xffffffff00000000ULL) | val;
605             if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
606                 /* Enable main counter and interrupt generation. */
607                 s->hpet_offset =
608                     ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
609                 for (i = 0; i < s->num_timers; i++) {
610                     if ((&s->timer[i])->cmp != ~0ULL) {
611                         hpet_set_timer(&s->timer[i]);
612                     }
613                 }
614             } else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
615                 /* Halt main counter and disable interrupt generation. */
616                 s->hpet_counter = hpet_get_ticks(s);
617                 for (i = 0; i < s->num_timers; i++) {
618                     hpet_del_timer(&s->timer[i]);
619                 }
620             }
621             /* i8254 and RTC output pins are disabled
622              * when HPET is in legacy mode */
623             if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
624                 qemu_set_irq(s->pit_enabled, 0);
625                 qemu_irq_lower(s->irqs[0]);
626                 qemu_irq_lower(s->irqs[RTC_ISA_IRQ]);
627             } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
628                 qemu_irq_lower(s->irqs[0]);
629                 qemu_set_irq(s->pit_enabled, 1);
630                 qemu_set_irq(s->irqs[RTC_ISA_IRQ], s->rtc_irq_level);
631             }
632             break;
633         case HPET_CFG + 4:
634             DPRINTF("qemu: invalid HPET_CFG+4 write\n");
635             break;
636         case HPET_STATUS:
637             val = new_val & s->isr;
638             for (i = 0; i < s->num_timers; i++) {
639                 if (val & (1 << i)) {
640                     update_irq(&s->timer[i], 0);
641                 }
642             }
643             break;
644         case HPET_COUNTER:
645             if (hpet_enabled(s)) {
646                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
647             }
648             s->hpet_counter =
649                 (s->hpet_counter & 0xffffffff00000000ULL) | value;
650             DPRINTF("qemu: HPET counter written. ctr = 0x%" PRIx64 " -> "
651                     "%" PRIx64 "\n", value, s->hpet_counter);
652             break;
653         case HPET_COUNTER + 4:
654             if (hpet_enabled(s)) {
655                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
656             }
657             s->hpet_counter =
658                 (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);
659             DPRINTF("qemu: HPET counter + 4 written. ctr = 0x%" PRIx64 " -> "
660                     "%" PRIx64 "\n", value, s->hpet_counter);
661             break;
662         default:
663             DPRINTF("qemu: invalid hpet_ram_writel\n");
664             break;
665         }
666     }
667 }
668 
669 static const MemoryRegionOps hpet_ram_ops = {
670     .read = hpet_ram_read,
671     .write = hpet_ram_write,
672     .valid = {
673         .min_access_size = 4,
674         .max_access_size = 4,
675     },
676     .endianness = DEVICE_NATIVE_ENDIAN,
677 };
678 
679 static void hpet_reset(DeviceState *d)
680 {
681     HPETState *s = HPET(d);
682     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
683     int i;
684 
685     for (i = 0; i < s->num_timers; i++) {
686         HPETTimer *timer = &s->timer[i];
687 
688         hpet_del_timer(timer);
689         timer->cmp = ~0ULL;
690         timer->config = HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;
691         if (s->flags & (1 << HPET_MSI_SUPPORT)) {
692             timer->config |= HPET_TN_FSB_CAP;
693         }
694         /* advertise availability of ioapic int */
695         timer->config |=  (uint64_t)s->intcap << 32;
696         timer->period = 0ULL;
697         timer->wrap_flag = 0;
698     }
699 
700     qemu_set_irq(s->pit_enabled, 1);
701     s->hpet_counter = 0ULL;
702     s->hpet_offset = 0ULL;
703     s->config = 0ULL;
704     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
705     hpet_cfg.hpet[s->hpet_id].address = sbd->mmio[0].addr;
706 
707     /* to document that the RTC lowers its output on reset as well */
708     s->rtc_irq_level = 0;
709 }
710 
711 static void hpet_handle_legacy_irq(void *opaque, int n, int level)
712 {
713     HPETState *s = HPET(opaque);
714 
715     if (n == HPET_LEGACY_PIT_INT) {
716         if (!hpet_in_legacy_mode(s)) {
717             qemu_set_irq(s->irqs[0], level);
718         }
719     } else {
720         s->rtc_irq_level = level;
721         if (!hpet_in_legacy_mode(s)) {
722             qemu_set_irq(s->irqs[RTC_ISA_IRQ], level);
723         }
724     }
725 }
726 
727 static void hpet_init(Object *obj)
728 {
729     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
730     HPETState *s = HPET(obj);
731 
732     /* HPET Area */
733     memory_region_init_io(&s->iomem, obj, &hpet_ram_ops, s, "hpet", HPET_LEN);
734     sysbus_init_mmio(sbd, &s->iomem);
735 }
736 
737 static void hpet_realize(DeviceState *dev, Error **errp)
738 {
739     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
740     HPETState *s = HPET(dev);
741     int i;
742     HPETTimer *timer;
743 
744     if (!s->intcap) {
745         warn_report("Hpet's intcap not initialized");
746     }
747     if (hpet_cfg.count == UINT8_MAX) {
748         /* first instance */
749         hpet_cfg.count = 0;
750     }
751 
752     if (hpet_cfg.count == 8) {
753         error_setg(errp, "Only 8 instances of HPET is allowed");
754         return;
755     }
756 
757     s->hpet_id = hpet_cfg.count++;
758 
759     for (i = 0; i < HPET_NUM_IRQ_ROUTES; i++) {
760         sysbus_init_irq(sbd, &s->irqs[i]);
761     }
762 
763     if (s->num_timers < HPET_MIN_TIMERS) {
764         s->num_timers = HPET_MIN_TIMERS;
765     } else if (s->num_timers > HPET_MAX_TIMERS) {
766         s->num_timers = HPET_MAX_TIMERS;
767     }
768     for (i = 0; i < HPET_MAX_TIMERS; i++) {
769         timer = &s->timer[i];
770         timer->qemu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, hpet_timer, timer);
771         timer->tn = i;
772         timer->state = s;
773     }
774 
775     /* 64-bit main counter; LegacyReplacementRoute. */
776     s->capability = 0x8086a001ULL;
777     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
778     s->capability |= ((uint64_t)(HPET_CLK_PERIOD * FS_PER_NS) << 32);
779 
780     qdev_init_gpio_in(dev, hpet_handle_legacy_irq, 2);
781     qdev_init_gpio_out(dev, &s->pit_enabled, 1);
782 }
783 
784 static Property hpet_device_properties[] = {
785     DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
786     DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
787     DEFINE_PROP_UINT32(HPET_INTCAP, HPETState, intcap, 0),
788     DEFINE_PROP_BOOL("hpet-offset-saved", HPETState, hpet_offset_saved, true),
789     DEFINE_PROP_END_OF_LIST(),
790 };
791 
792 static void hpet_device_class_init(ObjectClass *klass, void *data)
793 {
794     DeviceClass *dc = DEVICE_CLASS(klass);
795 
796     dc->realize = hpet_realize;
797     dc->reset = hpet_reset;
798     dc->vmsd = &vmstate_hpet;
799     device_class_set_props(dc, hpet_device_properties);
800 }
801 
802 static const TypeInfo hpet_device_info = {
803     .name          = TYPE_HPET,
804     .parent        = TYPE_SYS_BUS_DEVICE,
805     .instance_size = sizeof(HPETState),
806     .instance_init = hpet_init,
807     .class_init    = hpet_device_class_init,
808 };
809 
810 static void hpet_register_types(void)
811 {
812     type_register_static(&hpet_device_info);
813 }
814 
815 type_init(hpet_register_types)
816