xref: /openbmc/qemu/hw/timer/hpet.c (revision 4a66d3bf)
1 /*
2  *  High Precisition 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 "hw/hw.h"
28 #include "hw/i386/pc.h"
29 #include "ui/console.h"
30 #include "qemu/timer.h"
31 #include "hw/timer/hpet.h"
32 #include "hw/sysbus.h"
33 #include "hw/timer/mc146818rtc.h"
34 #include "hw/timer/i8254.h"
35 
36 //#define HPET_DEBUG
37 #ifdef HPET_DEBUG
38 #define DPRINTF printf
39 #else
40 #define DPRINTF(...)
41 #endif
42 
43 #define HPET_MSI_SUPPORT        0
44 
45 #define HPET(obj) OBJECT_CHECK(HPETState, (obj), TYPE_HPET)
46 
47 struct HPETState;
48 typedef struct HPETTimer {  /* timers */
49     uint8_t tn;             /*timer number*/
50     QEMUTimer *qemu_timer;
51     struct HPETState *state;
52     /* Memory-mapped, software visible timer registers */
53     uint64_t config;        /* configuration/cap */
54     uint64_t cmp;           /* comparator */
55     uint64_t fsb;           /* FSB route */
56     /* Hidden register state */
57     uint64_t period;        /* Last value written to comparator */
58     uint8_t wrap_flag;      /* timer pop will indicate wrap for one-shot 32-bit
59                              * mode. Next pop will be actual timer expiration.
60                              */
61 } HPETTimer;
62 
63 typedef struct HPETState {
64     /*< private >*/
65     SysBusDevice parent_obj;
66     /*< public >*/
67 
68     MemoryRegion iomem;
69     uint64_t hpet_offset;
70     qemu_irq irqs[HPET_NUM_IRQ_ROUTES];
71     uint32_t flags;
72     uint8_t rtc_irq_level;
73     qemu_irq pit_enabled;
74     uint8_t num_timers;
75     uint32_t intcap;
76     HPETTimer timer[HPET_MAX_TIMERS];
77 
78     /* Memory-mapped, software visible registers */
79     uint64_t capability;        /* capabilities */
80     uint64_t config;            /* configuration */
81     uint64_t isr;               /* interrupt status reg */
82     uint64_t hpet_counter;      /* main counter */
83     uint8_t  hpet_id;           /* instance id */
84 } HPETState;
85 
86 static uint32_t hpet_in_legacy_mode(HPETState *s)
87 {
88     return s->config & HPET_CFG_LEGACY;
89 }
90 
91 static uint32_t timer_int_route(struct HPETTimer *timer)
92 {
93     return (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;
94 }
95 
96 static uint32_t timer_fsb_route(HPETTimer *t)
97 {
98     return t->config & HPET_TN_FSB_ENABLE;
99 }
100 
101 static uint32_t hpet_enabled(HPETState *s)
102 {
103     return s->config & HPET_CFG_ENABLE;
104 }
105 
106 static uint32_t timer_is_periodic(HPETTimer *t)
107 {
108     return t->config & HPET_TN_PERIODIC;
109 }
110 
111 static uint32_t timer_enabled(HPETTimer *t)
112 {
113     return t->config & HPET_TN_ENABLE;
114 }
115 
116 static uint32_t hpet_time_after(uint64_t a, uint64_t b)
117 {
118     return ((int32_t)(b) - (int32_t)(a) < 0);
119 }
120 
121 static uint32_t hpet_time_after64(uint64_t a, uint64_t b)
122 {
123     return ((int64_t)(b) - (int64_t)(a) < 0);
124 }
125 
126 static uint64_t ticks_to_ns(uint64_t value)
127 {
128     return (muldiv64(value, HPET_CLK_PERIOD, FS_PER_NS));
129 }
130 
131 static uint64_t ns_to_ticks(uint64_t value)
132 {
133     return (muldiv64(value, FS_PER_NS, HPET_CLK_PERIOD));
134 }
135 
136 static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)
137 {
138     new &= mask;
139     new |= old & ~mask;
140     return new;
141 }
142 
143 static int activating_bit(uint64_t old, uint64_t new, uint64_t mask)
144 {
145     return (!(old & mask) && (new & mask));
146 }
147 
148 static int deactivating_bit(uint64_t old, uint64_t new, uint64_t mask)
149 {
150     return ((old & mask) && !(new & mask));
151 }
152 
153 static uint64_t hpet_get_ticks(HPETState *s)
154 {
155     return ns_to_ticks(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->hpet_offset);
156 }
157 
158 /*
159  * calculate diff between comparator value and current ticks
160  */
161 static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
162 {
163 
164     if (t->config & HPET_TN_32BIT) {
165         uint32_t diff, cmp;
166 
167         cmp = (uint32_t)t->cmp;
168         diff = cmp - (uint32_t)current;
169         diff = (int32_t)diff > 0 ? diff : (uint32_t)1;
170         return (uint64_t)diff;
171     } else {
172         uint64_t diff, cmp;
173 
174         cmp = t->cmp;
175         diff = cmp - current;
176         diff = (int64_t)diff > 0 ? diff : (uint64_t)1;
177         return diff;
178     }
179 }
180 
181 static void update_irq(struct HPETTimer *timer, int set)
182 {
183     uint64_t mask;
184     HPETState *s;
185     int route;
186 
187     if (timer->tn <= 1 && hpet_in_legacy_mode(timer->state)) {
188         /* if LegacyReplacementRoute bit is set, HPET specification requires
189          * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,
190          * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.
191          */
192         route = (timer->tn == 0) ? 0 : RTC_ISA_IRQ;
193     } else {
194         route = timer_int_route(timer);
195     }
196     s = timer->state;
197     mask = 1 << timer->tn;
198     if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
199         s->isr &= ~mask;
200         if (!timer_fsb_route(timer)) {
201             /* fold the ICH PIRQ# pin's internal inversion logic into hpet */
202             if (route >= ISA_NUM_IRQS) {
203                 qemu_irq_raise(s->irqs[route]);
204             } else {
205                 qemu_irq_lower(s->irqs[route]);
206             }
207         }
208     } else if (timer_fsb_route(timer)) {
209         stl_le_phys(&address_space_memory,
210                     timer->fsb >> 32, timer->fsb & 0xffffffff);
211     } else if (timer->config & HPET_TN_TYPE_LEVEL) {
212         s->isr |= mask;
213         /* fold the ICH PIRQ# pin's internal inversion logic into hpet */
214         if (route >= ISA_NUM_IRQS) {
215             qemu_irq_lower(s->irqs[route]);
216         } else {
217             qemu_irq_raise(s->irqs[route]);
218         }
219     } else {
220         s->isr &= ~mask;
221         qemu_irq_pulse(s->irqs[route]);
222     }
223 }
224 
225 static void hpet_pre_save(void *opaque)
226 {
227     HPETState *s = opaque;
228 
229     /* save current counter value */
230     s->hpet_counter = hpet_get_ticks(s);
231 }
232 
233 static int hpet_pre_load(void *opaque)
234 {
235     HPETState *s = opaque;
236 
237     /* version 1 only supports 3, later versions will load the actual value */
238     s->num_timers = HPET_MIN_TIMERS;
239     return 0;
240 }
241 
242 static int hpet_post_load(void *opaque, int version_id)
243 {
244     HPETState *s = opaque;
245 
246     /* Recalculate the offset between the main counter and guest time */
247     s->hpet_offset = ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
248 
249     /* Push number of timers into capability returned via HPET_ID */
250     s->capability &= ~HPET_ID_NUM_TIM_MASK;
251     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
252     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
253 
254     /* Derive HPET_MSI_SUPPORT from the capability of the first timer. */
255     s->flags &= ~(1 << HPET_MSI_SUPPORT);
256     if (s->timer[0].config & HPET_TN_FSB_CAP) {
257         s->flags |= 1 << HPET_MSI_SUPPORT;
258     }
259     return 0;
260 }
261 
262 static bool hpet_rtc_irq_level_needed(void *opaque)
263 {
264     HPETState *s = opaque;
265 
266     return s->rtc_irq_level != 0;
267 }
268 
269 static const VMStateDescription vmstate_hpet_rtc_irq_level = {
270     .name = "hpet/rtc_irq_level",
271     .version_id = 1,
272     .minimum_version_id = 1,
273     .minimum_version_id_old = 1,
274     .fields      = (VMStateField[]) {
275         VMSTATE_UINT8(rtc_irq_level, HPETState),
276         VMSTATE_END_OF_LIST()
277     }
278 };
279 
280 static const VMStateDescription vmstate_hpet_timer = {
281     .name = "hpet_timer",
282     .version_id = 1,
283     .minimum_version_id = 1,
284     .minimum_version_id_old = 1,
285     .fields      = (VMStateField []) {
286         VMSTATE_UINT8(tn, HPETTimer),
287         VMSTATE_UINT64(config, HPETTimer),
288         VMSTATE_UINT64(cmp, HPETTimer),
289         VMSTATE_UINT64(fsb, HPETTimer),
290         VMSTATE_UINT64(period, HPETTimer),
291         VMSTATE_UINT8(wrap_flag, HPETTimer),
292         VMSTATE_TIMER(qemu_timer, HPETTimer),
293         VMSTATE_END_OF_LIST()
294     }
295 };
296 
297 static const VMStateDescription vmstate_hpet = {
298     .name = "hpet",
299     .version_id = 2,
300     .minimum_version_id = 1,
301     .minimum_version_id_old = 1,
302     .pre_save = hpet_pre_save,
303     .pre_load = hpet_pre_load,
304     .post_load = hpet_post_load,
305     .fields      = (VMStateField []) {
306         VMSTATE_UINT64(config, HPETState),
307         VMSTATE_UINT64(isr, HPETState),
308         VMSTATE_UINT64(hpet_counter, HPETState),
309         VMSTATE_UINT8_V(num_timers, HPETState, 2),
310         VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0,
311                                     vmstate_hpet_timer, HPETTimer),
312         VMSTATE_END_OF_LIST()
313     },
314     .subsections = (VMStateSubsection[]) {
315         {
316             .vmsd = &vmstate_hpet_rtc_irq_level,
317             .needed = hpet_rtc_irq_level_needed,
318         }, {
319             /* empty */
320         }
321     }
322 };
323 
324 /*
325  * timer expiration callback
326  */
327 static void hpet_timer(void *opaque)
328 {
329     HPETTimer *t = opaque;
330     uint64_t diff;
331 
332     uint64_t period = t->period;
333     uint64_t cur_tick = hpet_get_ticks(t->state);
334 
335     if (timer_is_periodic(t) && period != 0) {
336         if (t->config & HPET_TN_32BIT) {
337             while (hpet_time_after(cur_tick, t->cmp)) {
338                 t->cmp = (uint32_t)(t->cmp + t->period);
339             }
340         } else {
341             while (hpet_time_after64(cur_tick, t->cmp)) {
342                 t->cmp += period;
343             }
344         }
345         diff = hpet_calculate_diff(t, cur_tick);
346         timer_mod(t->qemu_timer,
347                        qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
348     } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
349         if (t->wrap_flag) {
350             diff = hpet_calculate_diff(t, cur_tick);
351             timer_mod(t->qemu_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
352                            (int64_t)ticks_to_ns(diff));
353             t->wrap_flag = 0;
354         }
355     }
356     update_irq(t, 1);
357 }
358 
359 static void hpet_set_timer(HPETTimer *t)
360 {
361     uint64_t diff;
362     uint32_t wrap_diff;  /* how many ticks until we wrap? */
363     uint64_t cur_tick = hpet_get_ticks(t->state);
364 
365     /* whenever new timer is being set up, make sure wrap_flag is 0 */
366     t->wrap_flag = 0;
367     diff = hpet_calculate_diff(t, cur_tick);
368 
369     /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
370      * counter wraps in addition to an interrupt with comparator match.
371      */
372     if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
373         wrap_diff = 0xffffffff - (uint32_t)cur_tick;
374         if (wrap_diff < (uint32_t)diff) {
375             diff = wrap_diff;
376             t->wrap_flag = 1;
377         }
378     }
379     timer_mod(t->qemu_timer,
380                    qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
381 }
382 
383 static void hpet_del_timer(HPETTimer *t)
384 {
385     timer_del(t->qemu_timer);
386     update_irq(t, 0);
387 }
388 
389 #ifdef HPET_DEBUG
390 static uint32_t hpet_ram_readb(void *opaque, hwaddr addr)
391 {
392     printf("qemu: hpet_read b at %" PRIx64 "\n", addr);
393     return 0;
394 }
395 
396 static uint32_t hpet_ram_readw(void *opaque, hwaddr addr)
397 {
398     printf("qemu: hpet_read w at %" PRIx64 "\n", addr);
399     return 0;
400 }
401 #endif
402 
403 static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
404                               unsigned size)
405 {
406     HPETState *s = opaque;
407     uint64_t cur_tick, index;
408 
409     DPRINTF("qemu: Enter hpet_ram_readl at %" PRIx64 "\n", addr);
410     index = addr;
411     /*address range of all TN regs*/
412     if (index >= 0x100 && index <= 0x3ff) {
413         uint8_t timer_id = (addr - 0x100) / 0x20;
414         HPETTimer *timer = &s->timer[timer_id];
415 
416         if (timer_id > s->num_timers) {
417             DPRINTF("qemu: timer id out of range\n");
418             return 0;
419         }
420 
421         switch ((addr - 0x100) % 0x20) {
422         case HPET_TN_CFG:
423             return timer->config;
424         case HPET_TN_CFG + 4: // Interrupt capabilities
425             return timer->config >> 32;
426         case HPET_TN_CMP: // comparator register
427             return timer->cmp;
428         case HPET_TN_CMP + 4:
429             return timer->cmp >> 32;
430         case HPET_TN_ROUTE:
431             return timer->fsb;
432         case HPET_TN_ROUTE + 4:
433             return timer->fsb >> 32;
434         default:
435             DPRINTF("qemu: invalid hpet_ram_readl\n");
436             break;
437         }
438     } else {
439         switch (index) {
440         case HPET_ID:
441             return s->capability;
442         case HPET_PERIOD:
443             return s->capability >> 32;
444         case HPET_CFG:
445             return s->config;
446         case HPET_CFG + 4:
447             DPRINTF("qemu: invalid HPET_CFG + 4 hpet_ram_readl\n");
448             return 0;
449         case HPET_COUNTER:
450             if (hpet_enabled(s)) {
451                 cur_tick = hpet_get_ticks(s);
452             } else {
453                 cur_tick = s->hpet_counter;
454             }
455             DPRINTF("qemu: reading counter  = %" PRIx64 "\n", cur_tick);
456             return cur_tick;
457         case HPET_COUNTER + 4:
458             if (hpet_enabled(s)) {
459                 cur_tick = hpet_get_ticks(s);
460             } else {
461                 cur_tick = s->hpet_counter;
462             }
463             DPRINTF("qemu: reading counter + 4  = %" PRIx64 "\n", cur_tick);
464             return cur_tick >> 32;
465         case HPET_STATUS:
466             return s->isr;
467         default:
468             DPRINTF("qemu: invalid hpet_ram_readl\n");
469             break;
470         }
471     }
472     return 0;
473 }
474 
475 static void hpet_ram_write(void *opaque, hwaddr addr,
476                            uint64_t value, unsigned size)
477 {
478     int i;
479     HPETState *s = opaque;
480     uint64_t old_val, new_val, val, index;
481 
482     DPRINTF("qemu: Enter hpet_ram_writel at %" PRIx64 " = %#x\n", addr, value);
483     index = addr;
484     old_val = hpet_ram_read(opaque, addr, 4);
485     new_val = value;
486 
487     /*address range of all TN regs*/
488     if (index >= 0x100 && index <= 0x3ff) {
489         uint8_t timer_id = (addr - 0x100) / 0x20;
490         HPETTimer *timer = &s->timer[timer_id];
491 
492         DPRINTF("qemu: hpet_ram_writel timer_id = %#x\n", timer_id);
493         if (timer_id > s->num_timers) {
494             DPRINTF("qemu: timer id out of range\n");
495             return;
496         }
497         switch ((addr - 0x100) % 0x20) {
498         case HPET_TN_CFG:
499             DPRINTF("qemu: hpet_ram_writel HPET_TN_CFG\n");
500             if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
501                 update_irq(timer, 0);
502             }
503             val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
504             timer->config = (timer->config & 0xffffffff00000000ULL) | val;
505             if (new_val & HPET_TN_32BIT) {
506                 timer->cmp = (uint32_t)timer->cmp;
507                 timer->period = (uint32_t)timer->period;
508             }
509             if (activating_bit(old_val, new_val, HPET_TN_ENABLE) &&
510                 hpet_enabled(s)) {
511                 hpet_set_timer(timer);
512             } else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
513                 hpet_del_timer(timer);
514             }
515             break;
516         case HPET_TN_CFG + 4: // Interrupt capabilities
517             DPRINTF("qemu: invalid HPET_TN_CFG+4 write\n");
518             break;
519         case HPET_TN_CMP: // comparator register
520             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP\n");
521             if (timer->config & HPET_TN_32BIT) {
522                 new_val = (uint32_t)new_val;
523             }
524             if (!timer_is_periodic(timer)
525                 || (timer->config & HPET_TN_SETVAL)) {
526                 timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;
527             }
528             if (timer_is_periodic(timer)) {
529                 /*
530                  * FIXME: Clamp period to reasonable min value?
531                  * Clamp period to reasonable max value
532                  */
533                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
534                 timer->period =
535                     (timer->period & 0xffffffff00000000ULL) | new_val;
536             }
537             timer->config &= ~HPET_TN_SETVAL;
538             if (hpet_enabled(s)) {
539                 hpet_set_timer(timer);
540             }
541             break;
542         case HPET_TN_CMP + 4: // comparator register high order
543             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");
544             if (!timer_is_periodic(timer)
545                 || (timer->config & HPET_TN_SETVAL)) {
546                 timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;
547             } else {
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 & 0xffffffffULL) | new_val << 32;
555                 }
556                 timer->config &= ~HPET_TN_SETVAL;
557                 if (hpet_enabled(s)) {
558                     hpet_set_timer(timer);
559                 }
560                 break;
561         case HPET_TN_ROUTE:
562             timer->fsb = (timer->fsb & 0xffffffff00000000ULL) | new_val;
563             break;
564         case HPET_TN_ROUTE + 4:
565             timer->fsb = (new_val << 32) | (timer->fsb & 0xffffffff);
566             break;
567         default:
568             DPRINTF("qemu: invalid hpet_ram_writel\n");
569             break;
570         }
571         return;
572     } else {
573         switch (index) {
574         case HPET_ID:
575             return;
576         case HPET_CFG:
577             val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
578             s->config = (s->config & 0xffffffff00000000ULL) | val;
579             if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
580                 /* Enable main counter and interrupt generation. */
581                 s->hpet_offset =
582                     ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
583                 for (i = 0; i < s->num_timers; i++) {
584                     if ((&s->timer[i])->cmp != ~0ULL) {
585                         hpet_set_timer(&s->timer[i]);
586                     }
587                 }
588             } else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
589                 /* Halt main counter and disable interrupt generation. */
590                 s->hpet_counter = hpet_get_ticks(s);
591                 for (i = 0; i < s->num_timers; i++) {
592                     hpet_del_timer(&s->timer[i]);
593                 }
594             }
595             /* i8254 and RTC output pins are disabled
596              * when HPET is in legacy mode */
597             if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
598                 qemu_set_irq(s->pit_enabled, 0);
599                 qemu_irq_lower(s->irqs[0]);
600                 qemu_irq_lower(s->irqs[RTC_ISA_IRQ]);
601             } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
602                 qemu_irq_lower(s->irqs[0]);
603                 qemu_set_irq(s->pit_enabled, 1);
604                 qemu_set_irq(s->irqs[RTC_ISA_IRQ], s->rtc_irq_level);
605             }
606             break;
607         case HPET_CFG + 4:
608             DPRINTF("qemu: invalid HPET_CFG+4 write\n");
609             break;
610         case HPET_STATUS:
611             val = new_val & s->isr;
612             for (i = 0; i < s->num_timers; i++) {
613                 if (val & (1 << i)) {
614                     update_irq(&s->timer[i], 0);
615                 }
616             }
617             break;
618         case HPET_COUNTER:
619             if (hpet_enabled(s)) {
620                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
621             }
622             s->hpet_counter =
623                 (s->hpet_counter & 0xffffffff00000000ULL) | value;
624             DPRINTF("qemu: HPET counter written. ctr = %#x -> %" PRIx64 "\n",
625                     value, s->hpet_counter);
626             break;
627         case HPET_COUNTER + 4:
628             if (hpet_enabled(s)) {
629                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
630             }
631             s->hpet_counter =
632                 (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);
633             DPRINTF("qemu: HPET counter + 4 written. ctr = %#x -> %" PRIx64 "\n",
634                     value, s->hpet_counter);
635             break;
636         default:
637             DPRINTF("qemu: invalid hpet_ram_writel\n");
638             break;
639         }
640     }
641 }
642 
643 static const MemoryRegionOps hpet_ram_ops = {
644     .read = hpet_ram_read,
645     .write = hpet_ram_write,
646     .valid = {
647         .min_access_size = 4,
648         .max_access_size = 4,
649     },
650     .endianness = DEVICE_NATIVE_ENDIAN,
651 };
652 
653 static void hpet_reset(DeviceState *d)
654 {
655     HPETState *s = HPET(d);
656     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
657     int i;
658 
659     for (i = 0; i < s->num_timers; i++) {
660         HPETTimer *timer = &s->timer[i];
661 
662         hpet_del_timer(timer);
663         timer->cmp = ~0ULL;
664         timer->config = HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;
665         if (s->flags & (1 << HPET_MSI_SUPPORT)) {
666             timer->config |= HPET_TN_FSB_CAP;
667         }
668         /* advertise availability of ioapic int */
669         timer->config |=  (uint64_t)s->intcap << 32;
670         timer->period = 0ULL;
671         timer->wrap_flag = 0;
672     }
673 
674     qemu_set_irq(s->pit_enabled, 1);
675     s->hpet_counter = 0ULL;
676     s->hpet_offset = 0ULL;
677     s->config = 0ULL;
678     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
679     hpet_cfg.hpet[s->hpet_id].address = sbd->mmio[0].addr;
680 
681     /* to document that the RTC lowers its output on reset as well */
682     s->rtc_irq_level = 0;
683 }
684 
685 static void hpet_handle_legacy_irq(void *opaque, int n, int level)
686 {
687     HPETState *s = HPET(opaque);
688 
689     if (n == HPET_LEGACY_PIT_INT) {
690         if (!hpet_in_legacy_mode(s)) {
691             qemu_set_irq(s->irqs[0], level);
692         }
693     } else {
694         s->rtc_irq_level = level;
695         if (!hpet_in_legacy_mode(s)) {
696             qemu_set_irq(s->irqs[RTC_ISA_IRQ], level);
697         }
698     }
699 }
700 
701 static void hpet_init(Object *obj)
702 {
703     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
704     HPETState *s = HPET(obj);
705 
706     /* HPET Area */
707     memory_region_init_io(&s->iomem, obj, &hpet_ram_ops, s, "hpet", 0x400);
708     sysbus_init_mmio(sbd, &s->iomem);
709 }
710 
711 static void hpet_realize(DeviceState *dev, Error **errp)
712 {
713     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
714     HPETState *s = HPET(dev);
715     int i;
716     HPETTimer *timer;
717 
718     if (!s->intcap) {
719         error_printf("Hpet's intcap not initialized.\n");
720     }
721     if (hpet_cfg.count == UINT8_MAX) {
722         /* first instance */
723         hpet_cfg.count = 0;
724     }
725 
726     if (hpet_cfg.count == 8) {
727         error_setg(errp, "Only 8 instances of HPET is allowed");
728         return;
729     }
730 
731     s->hpet_id = hpet_cfg.count++;
732 
733     for (i = 0; i < HPET_NUM_IRQ_ROUTES; i++) {
734         sysbus_init_irq(sbd, &s->irqs[i]);
735     }
736 
737     if (s->num_timers < HPET_MIN_TIMERS) {
738         s->num_timers = HPET_MIN_TIMERS;
739     } else if (s->num_timers > HPET_MAX_TIMERS) {
740         s->num_timers = HPET_MAX_TIMERS;
741     }
742     for (i = 0; i < HPET_MAX_TIMERS; i++) {
743         timer = &s->timer[i];
744         timer->qemu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, hpet_timer, timer);
745         timer->tn = i;
746         timer->state = s;
747     }
748 
749     /* 64-bit main counter; LegacyReplacementRoute. */
750     s->capability = 0x8086a001ULL;
751     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
752     s->capability |= ((HPET_CLK_PERIOD) << 32);
753 
754     qdev_init_gpio_in(dev, hpet_handle_legacy_irq, 2);
755     qdev_init_gpio_out(dev, &s->pit_enabled, 1);
756 }
757 
758 static Property hpet_device_properties[] = {
759     DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
760     DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
761     DEFINE_PROP_UINT32(HPET_INTCAP, HPETState, intcap, 0),
762     DEFINE_PROP_END_OF_LIST(),
763 };
764 
765 static void hpet_device_class_init(ObjectClass *klass, void *data)
766 {
767     DeviceClass *dc = DEVICE_CLASS(klass);
768 
769     dc->realize = hpet_realize;
770     dc->reset = hpet_reset;
771     dc->vmsd = &vmstate_hpet;
772     dc->props = hpet_device_properties;
773 }
774 
775 static const TypeInfo hpet_device_info = {
776     .name          = TYPE_HPET,
777     .parent        = TYPE_SYS_BUS_DEVICE,
778     .instance_size = sizeof(HPETState),
779     .instance_init = hpet_init,
780     .class_init    = hpet_device_class_init,
781 };
782 
783 static void hpet_register_types(void)
784 {
785     type_register_static(&hpet_device_info);
786 }
787 
788 type_init(hpet_register_types)
789