xref: /openbmc/qemu/hw/timer/hpet.c (revision 786a4ea8)
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 "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         address_space_stl_le(&address_space_memory, timer->fsb >> 32,
210                              timer->fsb & 0xffffffff, MEMTXATTRS_UNSPECIFIED,
211                              NULL);
212     } else if (timer->config & HPET_TN_TYPE_LEVEL) {
213         s->isr |= mask;
214         /* fold the ICH PIRQ# pin's internal inversion logic into hpet */
215         if (route >= ISA_NUM_IRQS) {
216             qemu_irq_lower(s->irqs[route]);
217         } else {
218             qemu_irq_raise(s->irqs[route]);
219         }
220     } else {
221         s->isr &= ~mask;
222         qemu_irq_pulse(s->irqs[route]);
223     }
224 }
225 
226 static void hpet_pre_save(void *opaque)
227 {
228     HPETState *s = opaque;
229 
230     /* save current counter value */
231     s->hpet_counter = hpet_get_ticks(s);
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     s->hpet_offset = ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
261 
262     /* Push number of timers into capability returned via HPET_ID */
263     s->capability &= ~HPET_ID_NUM_TIM_MASK;
264     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
265     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
266 
267     /* Derive HPET_MSI_SUPPORT from the capability of the first timer. */
268     s->flags &= ~(1 << HPET_MSI_SUPPORT);
269     if (s->timer[0].config & HPET_TN_FSB_CAP) {
270         s->flags |= 1 << HPET_MSI_SUPPORT;
271     }
272     return 0;
273 }
274 
275 static bool hpet_rtc_irq_level_needed(void *opaque)
276 {
277     HPETState *s = opaque;
278 
279     return s->rtc_irq_level != 0;
280 }
281 
282 static const VMStateDescription vmstate_hpet_rtc_irq_level = {
283     .name = "hpet/rtc_irq_level",
284     .version_id = 1,
285     .minimum_version_id = 1,
286     .fields = (VMStateField[]) {
287         VMSTATE_UINT8(rtc_irq_level, HPETState),
288         VMSTATE_END_OF_LIST()
289     }
290 };
291 
292 static const VMStateDescription vmstate_hpet_timer = {
293     .name = "hpet_timer",
294     .version_id = 1,
295     .minimum_version_id = 1,
296     .fields = (VMStateField[]) {
297         VMSTATE_UINT8(tn, HPETTimer),
298         VMSTATE_UINT64(config, HPETTimer),
299         VMSTATE_UINT64(cmp, HPETTimer),
300         VMSTATE_UINT64(fsb, HPETTimer),
301         VMSTATE_UINT64(period, HPETTimer),
302         VMSTATE_UINT8(wrap_flag, HPETTimer),
303         VMSTATE_TIMER_PTR(qemu_timer, HPETTimer),
304         VMSTATE_END_OF_LIST()
305     }
306 };
307 
308 static const VMStateDescription vmstate_hpet = {
309     .name = "hpet",
310     .version_id = 2,
311     .minimum_version_id = 1,
312     .pre_save = hpet_pre_save,
313     .pre_load = hpet_pre_load,
314     .post_load = hpet_post_load,
315     .fields = (VMStateField[]) {
316         VMSTATE_UINT64(config, HPETState),
317         VMSTATE_UINT64(isr, HPETState),
318         VMSTATE_UINT64(hpet_counter, HPETState),
319         VMSTATE_UINT8_V(num_timers, HPETState, 2),
320         VMSTATE_VALIDATE("num_timers in range", hpet_validate_num_timers),
321         VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0,
322                                     vmstate_hpet_timer, HPETTimer),
323         VMSTATE_END_OF_LIST()
324     },
325     .subsections = (VMStateSubsection[]) {
326         {
327             .vmsd = &vmstate_hpet_rtc_irq_level,
328             .needed = hpet_rtc_irq_level_needed,
329         }, {
330             /* empty */
331         }
332     }
333 };
334 
335 /*
336  * timer expiration callback
337  */
338 static void hpet_timer(void *opaque)
339 {
340     HPETTimer *t = opaque;
341     uint64_t diff;
342 
343     uint64_t period = t->period;
344     uint64_t cur_tick = hpet_get_ticks(t->state);
345 
346     if (timer_is_periodic(t) && period != 0) {
347         if (t->config & HPET_TN_32BIT) {
348             while (hpet_time_after(cur_tick, t->cmp)) {
349                 t->cmp = (uint32_t)(t->cmp + t->period);
350             }
351         } else {
352             while (hpet_time_after64(cur_tick, t->cmp)) {
353                 t->cmp += period;
354             }
355         }
356         diff = hpet_calculate_diff(t, cur_tick);
357         timer_mod(t->qemu_timer,
358                        qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
359     } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
360         if (t->wrap_flag) {
361             diff = hpet_calculate_diff(t, cur_tick);
362             timer_mod(t->qemu_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
363                            (int64_t)ticks_to_ns(diff));
364             t->wrap_flag = 0;
365         }
366     }
367     update_irq(t, 1);
368 }
369 
370 static void hpet_set_timer(HPETTimer *t)
371 {
372     uint64_t diff;
373     uint32_t wrap_diff;  /* how many ticks until we wrap? */
374     uint64_t cur_tick = hpet_get_ticks(t->state);
375 
376     /* whenever new timer is being set up, make sure wrap_flag is 0 */
377     t->wrap_flag = 0;
378     diff = hpet_calculate_diff(t, cur_tick);
379 
380     /* hpet spec says in one-shot 32-bit mode, generate an interrupt when
381      * counter wraps in addition to an interrupt with comparator match.
382      */
383     if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {
384         wrap_diff = 0xffffffff - (uint32_t)cur_tick;
385         if (wrap_diff < (uint32_t)diff) {
386             diff = wrap_diff;
387             t->wrap_flag = 1;
388         }
389     }
390     timer_mod(t->qemu_timer,
391                    qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (int64_t)ticks_to_ns(diff));
392 }
393 
394 static void hpet_del_timer(HPETTimer *t)
395 {
396     timer_del(t->qemu_timer);
397     update_irq(t, 0);
398 }
399 
400 #ifdef HPET_DEBUG
401 static uint32_t hpet_ram_readb(void *opaque, hwaddr addr)
402 {
403     printf("qemu: hpet_read b at %" PRIx64 "\n", addr);
404     return 0;
405 }
406 
407 static uint32_t hpet_ram_readw(void *opaque, hwaddr addr)
408 {
409     printf("qemu: hpet_read w at %" PRIx64 "\n", addr);
410     return 0;
411 }
412 #endif
413 
414 static uint64_t hpet_ram_read(void *opaque, hwaddr addr,
415                               unsigned size)
416 {
417     HPETState *s = opaque;
418     uint64_t cur_tick, index;
419 
420     DPRINTF("qemu: Enter hpet_ram_readl at %" PRIx64 "\n", addr);
421     index = addr;
422     /*address range of all TN regs*/
423     if (index >= 0x100 && index <= 0x3ff) {
424         uint8_t timer_id = (addr - 0x100) / 0x20;
425         HPETTimer *timer = &s->timer[timer_id];
426 
427         if (timer_id > s->num_timers) {
428             DPRINTF("qemu: timer id out of range\n");
429             return 0;
430         }
431 
432         switch ((addr - 0x100) % 0x20) {
433         case HPET_TN_CFG:
434             return timer->config;
435         case HPET_TN_CFG + 4: // Interrupt capabilities
436             return timer->config >> 32;
437         case HPET_TN_CMP: // comparator register
438             return timer->cmp;
439         case HPET_TN_CMP + 4:
440             return timer->cmp >> 32;
441         case HPET_TN_ROUTE:
442             return timer->fsb;
443         case HPET_TN_ROUTE + 4:
444             return timer->fsb >> 32;
445         default:
446             DPRINTF("qemu: invalid hpet_ram_readl\n");
447             break;
448         }
449     } else {
450         switch (index) {
451         case HPET_ID:
452             return s->capability;
453         case HPET_PERIOD:
454             return s->capability >> 32;
455         case HPET_CFG:
456             return s->config;
457         case HPET_CFG + 4:
458             DPRINTF("qemu: invalid HPET_CFG + 4 hpet_ram_readl\n");
459             return 0;
460         case HPET_COUNTER:
461             if (hpet_enabled(s)) {
462                 cur_tick = hpet_get_ticks(s);
463             } else {
464                 cur_tick = s->hpet_counter;
465             }
466             DPRINTF("qemu: reading counter  = %" PRIx64 "\n", cur_tick);
467             return cur_tick;
468         case HPET_COUNTER + 4:
469             if (hpet_enabled(s)) {
470                 cur_tick = hpet_get_ticks(s);
471             } else {
472                 cur_tick = s->hpet_counter;
473             }
474             DPRINTF("qemu: reading counter + 4  = %" PRIx64 "\n", cur_tick);
475             return cur_tick >> 32;
476         case HPET_STATUS:
477             return s->isr;
478         default:
479             DPRINTF("qemu: invalid hpet_ram_readl\n");
480             break;
481         }
482     }
483     return 0;
484 }
485 
486 static void hpet_ram_write(void *opaque, hwaddr addr,
487                            uint64_t value, unsigned size)
488 {
489     int i;
490     HPETState *s = opaque;
491     uint64_t old_val, new_val, val, index;
492 
493     DPRINTF("qemu: Enter hpet_ram_writel at %" PRIx64 " = %#x\n", addr, value);
494     index = addr;
495     old_val = hpet_ram_read(opaque, addr, 4);
496     new_val = value;
497 
498     /*address range of all TN regs*/
499     if (index >= 0x100 && index <= 0x3ff) {
500         uint8_t timer_id = (addr - 0x100) / 0x20;
501         HPETTimer *timer = &s->timer[timer_id];
502 
503         DPRINTF("qemu: hpet_ram_writel timer_id = %#x\n", timer_id);
504         if (timer_id > s->num_timers) {
505             DPRINTF("qemu: timer id out of range\n");
506             return;
507         }
508         switch ((addr - 0x100) % 0x20) {
509         case HPET_TN_CFG:
510             DPRINTF("qemu: hpet_ram_writel HPET_TN_CFG\n");
511             if (activating_bit(old_val, new_val, HPET_TN_FSB_ENABLE)) {
512                 update_irq(timer, 0);
513             }
514             val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
515             timer->config = (timer->config & 0xffffffff00000000ULL) | val;
516             if (new_val & HPET_TN_32BIT) {
517                 timer->cmp = (uint32_t)timer->cmp;
518                 timer->period = (uint32_t)timer->period;
519             }
520             if (activating_bit(old_val, new_val, HPET_TN_ENABLE) &&
521                 hpet_enabled(s)) {
522                 hpet_set_timer(timer);
523             } else if (deactivating_bit(old_val, new_val, HPET_TN_ENABLE)) {
524                 hpet_del_timer(timer);
525             }
526             break;
527         case HPET_TN_CFG + 4: // Interrupt capabilities
528             DPRINTF("qemu: invalid HPET_TN_CFG+4 write\n");
529             break;
530         case HPET_TN_CMP: // comparator register
531             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP\n");
532             if (timer->config & HPET_TN_32BIT) {
533                 new_val = (uint32_t)new_val;
534             }
535             if (!timer_is_periodic(timer)
536                 || (timer->config & HPET_TN_SETVAL)) {
537                 timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;
538             }
539             if (timer_is_periodic(timer)) {
540                 /*
541                  * FIXME: Clamp period to reasonable min value?
542                  * Clamp period to reasonable max value
543                  */
544                 new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;
545                 timer->period =
546                     (timer->period & 0xffffffff00000000ULL) | new_val;
547             }
548             timer->config &= ~HPET_TN_SETVAL;
549             if (hpet_enabled(s)) {
550                 hpet_set_timer(timer);
551             }
552             break;
553         case HPET_TN_CMP + 4: // comparator register high order
554             DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");
555             if (!timer_is_periodic(timer)
556                 || (timer->config & HPET_TN_SETVAL)) {
557                 timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;
558             } else {
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 & 0xffffffffULL) | new_val << 32;
566                 }
567                 timer->config &= ~HPET_TN_SETVAL;
568                 if (hpet_enabled(s)) {
569                     hpet_set_timer(timer);
570                 }
571                 break;
572         case HPET_TN_ROUTE:
573             timer->fsb = (timer->fsb & 0xffffffff00000000ULL) | new_val;
574             break;
575         case HPET_TN_ROUTE + 4:
576             timer->fsb = (new_val << 32) | (timer->fsb & 0xffffffff);
577             break;
578         default:
579             DPRINTF("qemu: invalid hpet_ram_writel\n");
580             break;
581         }
582         return;
583     } else {
584         switch (index) {
585         case HPET_ID:
586             return;
587         case HPET_CFG:
588             val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);
589             s->config = (s->config & 0xffffffff00000000ULL) | val;
590             if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
591                 /* Enable main counter and interrupt generation. */
592                 s->hpet_offset =
593                     ticks_to_ns(s->hpet_counter) - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
594                 for (i = 0; i < s->num_timers; i++) {
595                     if ((&s->timer[i])->cmp != ~0ULL) {
596                         hpet_set_timer(&s->timer[i]);
597                     }
598                 }
599             } else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {
600                 /* Halt main counter and disable interrupt generation. */
601                 s->hpet_counter = hpet_get_ticks(s);
602                 for (i = 0; i < s->num_timers; i++) {
603                     hpet_del_timer(&s->timer[i]);
604                 }
605             }
606             /* i8254 and RTC output pins are disabled
607              * when HPET is in legacy mode */
608             if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
609                 qemu_set_irq(s->pit_enabled, 0);
610                 qemu_irq_lower(s->irqs[0]);
611                 qemu_irq_lower(s->irqs[RTC_ISA_IRQ]);
612             } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
613                 qemu_irq_lower(s->irqs[0]);
614                 qemu_set_irq(s->pit_enabled, 1);
615                 qemu_set_irq(s->irqs[RTC_ISA_IRQ], s->rtc_irq_level);
616             }
617             break;
618         case HPET_CFG + 4:
619             DPRINTF("qemu: invalid HPET_CFG+4 write\n");
620             break;
621         case HPET_STATUS:
622             val = new_val & s->isr;
623             for (i = 0; i < s->num_timers; i++) {
624                 if (val & (1 << i)) {
625                     update_irq(&s->timer[i], 0);
626                 }
627             }
628             break;
629         case HPET_COUNTER:
630             if (hpet_enabled(s)) {
631                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
632             }
633             s->hpet_counter =
634                 (s->hpet_counter & 0xffffffff00000000ULL) | value;
635             DPRINTF("qemu: HPET counter written. ctr = %#x -> %" PRIx64 "\n",
636                     value, s->hpet_counter);
637             break;
638         case HPET_COUNTER + 4:
639             if (hpet_enabled(s)) {
640                 DPRINTF("qemu: Writing counter while HPET enabled!\n");
641             }
642             s->hpet_counter =
643                 (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);
644             DPRINTF("qemu: HPET counter + 4 written. ctr = %#x -> %" PRIx64 "\n",
645                     value, s->hpet_counter);
646             break;
647         default:
648             DPRINTF("qemu: invalid hpet_ram_writel\n");
649             break;
650         }
651     }
652 }
653 
654 static const MemoryRegionOps hpet_ram_ops = {
655     .read = hpet_ram_read,
656     .write = hpet_ram_write,
657     .valid = {
658         .min_access_size = 4,
659         .max_access_size = 4,
660     },
661     .endianness = DEVICE_NATIVE_ENDIAN,
662 };
663 
664 static void hpet_reset(DeviceState *d)
665 {
666     HPETState *s = HPET(d);
667     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
668     int i;
669 
670     for (i = 0; i < s->num_timers; i++) {
671         HPETTimer *timer = &s->timer[i];
672 
673         hpet_del_timer(timer);
674         timer->cmp = ~0ULL;
675         timer->config = HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;
676         if (s->flags & (1 << HPET_MSI_SUPPORT)) {
677             timer->config |= HPET_TN_FSB_CAP;
678         }
679         /* advertise availability of ioapic int */
680         timer->config |=  (uint64_t)s->intcap << 32;
681         timer->period = 0ULL;
682         timer->wrap_flag = 0;
683     }
684 
685     qemu_set_irq(s->pit_enabled, 1);
686     s->hpet_counter = 0ULL;
687     s->hpet_offset = 0ULL;
688     s->config = 0ULL;
689     hpet_cfg.hpet[s->hpet_id].event_timer_block_id = (uint32_t)s->capability;
690     hpet_cfg.hpet[s->hpet_id].address = sbd->mmio[0].addr;
691 
692     /* to document that the RTC lowers its output on reset as well */
693     s->rtc_irq_level = 0;
694 }
695 
696 static void hpet_handle_legacy_irq(void *opaque, int n, int level)
697 {
698     HPETState *s = HPET(opaque);
699 
700     if (n == HPET_LEGACY_PIT_INT) {
701         if (!hpet_in_legacy_mode(s)) {
702             qemu_set_irq(s->irqs[0], level);
703         }
704     } else {
705         s->rtc_irq_level = level;
706         if (!hpet_in_legacy_mode(s)) {
707             qemu_set_irq(s->irqs[RTC_ISA_IRQ], level);
708         }
709     }
710 }
711 
712 static void hpet_init(Object *obj)
713 {
714     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
715     HPETState *s = HPET(obj);
716 
717     /* HPET Area */
718     memory_region_init_io(&s->iomem, obj, &hpet_ram_ops, s, "hpet", 0x400);
719     sysbus_init_mmio(sbd, &s->iomem);
720 }
721 
722 static void hpet_realize(DeviceState *dev, Error **errp)
723 {
724     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
725     HPETState *s = HPET(dev);
726     int i;
727     HPETTimer *timer;
728 
729     if (!s->intcap) {
730         error_printf("Hpet's intcap not initialized.\n");
731     }
732     if (hpet_cfg.count == UINT8_MAX) {
733         /* first instance */
734         hpet_cfg.count = 0;
735     }
736 
737     if (hpet_cfg.count == 8) {
738         error_setg(errp, "Only 8 instances of HPET is allowed");
739         return;
740     }
741 
742     s->hpet_id = hpet_cfg.count++;
743 
744     for (i = 0; i < HPET_NUM_IRQ_ROUTES; i++) {
745         sysbus_init_irq(sbd, &s->irqs[i]);
746     }
747 
748     if (s->num_timers < HPET_MIN_TIMERS) {
749         s->num_timers = HPET_MIN_TIMERS;
750     } else if (s->num_timers > HPET_MAX_TIMERS) {
751         s->num_timers = HPET_MAX_TIMERS;
752     }
753     for (i = 0; i < HPET_MAX_TIMERS; i++) {
754         timer = &s->timer[i];
755         timer->qemu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, hpet_timer, timer);
756         timer->tn = i;
757         timer->state = s;
758     }
759 
760     /* 64-bit main counter; LegacyReplacementRoute. */
761     s->capability = 0x8086a001ULL;
762     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
763     s->capability |= ((HPET_CLK_PERIOD) << 32);
764 
765     qdev_init_gpio_in(dev, hpet_handle_legacy_irq, 2);
766     qdev_init_gpio_out(dev, &s->pit_enabled, 1);
767 }
768 
769 static Property hpet_device_properties[] = {
770     DEFINE_PROP_UINT8("timers", HPETState, num_timers, HPET_MIN_TIMERS),
771     DEFINE_PROP_BIT("msi", HPETState, flags, HPET_MSI_SUPPORT, false),
772     DEFINE_PROP_UINT32(HPET_INTCAP, HPETState, intcap, 0),
773     DEFINE_PROP_END_OF_LIST(),
774 };
775 
776 static void hpet_device_class_init(ObjectClass *klass, void *data)
777 {
778     DeviceClass *dc = DEVICE_CLASS(klass);
779 
780     dc->realize = hpet_realize;
781     dc->reset = hpet_reset;
782     dc->vmsd = &vmstate_hpet;
783     dc->props = hpet_device_properties;
784 }
785 
786 static const TypeInfo hpet_device_info = {
787     .name          = TYPE_HPET,
788     .parent        = TYPE_SYS_BUS_DEVICE,
789     .instance_size = sizeof(HPETState),
790     .instance_init = hpet_init,
791     .class_init    = hpet_device_class_init,
792 };
793 
794 static void hpet_register_types(void)
795 {
796     type_register_static(&hpet_device_info);
797 }
798 
799 type_init(hpet_register_types)
800