xref: /openbmc/qemu/hw/timer/arm_timer.c (revision f3635813)
1 /*
2  * ARM PrimeCell Timer modules.
3  *
4  * Copyright (c) 2005-2006 CodeSourcery.
5  * Written by Paul Brook
6  *
7  * This code is licensed under the GPL.
8  */
9 
10 #include "qemu/osdep.h"
11 #include "hw/sysbus.h"
12 #include "migration/vmstate.h"
13 #include "qemu/timer.h"
14 #include "hw/irq.h"
15 #include "hw/ptimer.h"
16 #include "hw/qdev-properties.h"
17 #include "qemu/module.h"
18 #include "qemu/log.h"
19 
20 /* Common timer implementation.  */
21 
22 #define TIMER_CTRL_ONESHOT      (1 << 0)
23 #define TIMER_CTRL_32BIT        (1 << 1)
24 #define TIMER_CTRL_DIV1         (0 << 2)
25 #define TIMER_CTRL_DIV16        (1 << 2)
26 #define TIMER_CTRL_DIV256       (2 << 2)
27 #define TIMER_CTRL_IE           (1 << 5)
28 #define TIMER_CTRL_PERIODIC     (1 << 6)
29 #define TIMER_CTRL_ENABLE       (1 << 7)
30 
31 typedef struct {
32     ptimer_state *timer;
33     uint32_t control;
34     uint32_t limit;
35     int freq;
36     int int_level;
37     qemu_irq irq;
38 } arm_timer_state;
39 
40 /* Check all active timers, and schedule the next timer interrupt.  */
41 
42 static void arm_timer_update(arm_timer_state *s)
43 {
44     /* Update interrupts.  */
45     if (s->int_level && (s->control & TIMER_CTRL_IE)) {
46         qemu_irq_raise(s->irq);
47     } else {
48         qemu_irq_lower(s->irq);
49     }
50 }
51 
52 static uint32_t arm_timer_read(void *opaque, hwaddr offset)
53 {
54     arm_timer_state *s = (arm_timer_state *)opaque;
55 
56     switch (offset >> 2) {
57     case 0: /* TimerLoad */
58     case 6: /* TimerBGLoad */
59         return s->limit;
60     case 1: /* TimerValue */
61         return ptimer_get_count(s->timer);
62     case 2: /* TimerControl */
63         return s->control;
64     case 4: /* TimerRIS */
65         return s->int_level;
66     case 5: /* TimerMIS */
67         if ((s->control & TIMER_CTRL_IE) == 0)
68             return 0;
69         return s->int_level;
70     default:
71         qemu_log_mask(LOG_GUEST_ERROR,
72                       "%s: Bad offset %x\n", __func__, (int)offset);
73         return 0;
74     }
75 }
76 
77 /*
78  * Reset the timer limit after settings have changed.
79  * May only be called from inside a ptimer transaction block.
80  */
81 static void arm_timer_recalibrate(arm_timer_state *s, int reload)
82 {
83     uint32_t limit;
84 
85     if ((s->control & (TIMER_CTRL_PERIODIC | TIMER_CTRL_ONESHOT)) == 0) {
86         /* Free running.  */
87         if (s->control & TIMER_CTRL_32BIT)
88             limit = 0xffffffff;
89         else
90             limit = 0xffff;
91     } else {
92           /* Periodic.  */
93           limit = s->limit;
94     }
95     ptimer_set_limit(s->timer, limit, reload);
96 }
97 
98 static void arm_timer_write(void *opaque, hwaddr offset,
99                             uint32_t value)
100 {
101     arm_timer_state *s = (arm_timer_state *)opaque;
102     int freq;
103 
104     switch (offset >> 2) {
105     case 0: /* TimerLoad */
106         s->limit = value;
107         ptimer_transaction_begin(s->timer);
108         arm_timer_recalibrate(s, 1);
109         ptimer_transaction_commit(s->timer);
110         break;
111     case 1: /* TimerValue */
112         /* ??? Linux seems to want to write to this readonly register.
113            Ignore it.  */
114         break;
115     case 2: /* TimerControl */
116         ptimer_transaction_begin(s->timer);
117         if (s->control & TIMER_CTRL_ENABLE) {
118             /* Pause the timer if it is running.  This may cause some
119                inaccuracy dure to rounding, but avoids a whole lot of other
120                messyness.  */
121             ptimer_stop(s->timer);
122         }
123         s->control = value;
124         freq = s->freq;
125         /* ??? Need to recalculate expiry time after changing divisor.  */
126         switch ((value >> 2) & 3) {
127         case 1: freq >>= 4; break;
128         case 2: freq >>= 8; break;
129         }
130         arm_timer_recalibrate(s, s->control & TIMER_CTRL_ENABLE);
131         ptimer_set_freq(s->timer, freq);
132         if (s->control & TIMER_CTRL_ENABLE) {
133             /* Restart the timer if still enabled.  */
134             ptimer_run(s->timer, (s->control & TIMER_CTRL_ONESHOT) != 0);
135         }
136         ptimer_transaction_commit(s->timer);
137         break;
138     case 3: /* TimerIntClr */
139         s->int_level = 0;
140         break;
141     case 6: /* TimerBGLoad */
142         s->limit = value;
143         ptimer_transaction_begin(s->timer);
144         arm_timer_recalibrate(s, 0);
145         ptimer_transaction_commit(s->timer);
146         break;
147     default:
148         qemu_log_mask(LOG_GUEST_ERROR,
149                       "%s: Bad offset %x\n", __func__, (int)offset);
150     }
151     arm_timer_update(s);
152 }
153 
154 static void arm_timer_tick(void *opaque)
155 {
156     arm_timer_state *s = (arm_timer_state *)opaque;
157     s->int_level = 1;
158     arm_timer_update(s);
159 }
160 
161 static const VMStateDescription vmstate_arm_timer = {
162     .name = "arm_timer",
163     .version_id = 1,
164     .minimum_version_id = 1,
165     .fields = (VMStateField[]) {
166         VMSTATE_UINT32(control, arm_timer_state),
167         VMSTATE_UINT32(limit, arm_timer_state),
168         VMSTATE_INT32(int_level, arm_timer_state),
169         VMSTATE_PTIMER(timer, arm_timer_state),
170         VMSTATE_END_OF_LIST()
171     }
172 };
173 
174 static arm_timer_state *arm_timer_init(uint32_t freq)
175 {
176     arm_timer_state *s;
177 
178     s = (arm_timer_state *)g_malloc0(sizeof(arm_timer_state));
179     s->freq = freq;
180     s->control = TIMER_CTRL_IE;
181 
182     s->timer = ptimer_init(arm_timer_tick, s, PTIMER_POLICY_DEFAULT);
183     vmstate_register(NULL, -1, &vmstate_arm_timer, s);
184     return s;
185 }
186 
187 /* ARM PrimeCell SP804 dual timer module.
188  * Docs at
189  * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0271d/index.html
190 */
191 
192 #define TYPE_SP804 "sp804"
193 #define SP804(obj) OBJECT_CHECK(SP804State, (obj), TYPE_SP804)
194 
195 typedef struct SP804State {
196     SysBusDevice parent_obj;
197 
198     MemoryRegion iomem;
199     arm_timer_state *timer[2];
200     uint32_t freq0, freq1;
201     int level[2];
202     qemu_irq irq;
203 } SP804State;
204 
205 static const uint8_t sp804_ids[] = {
206     /* Timer ID */
207     0x04, 0x18, 0x14, 0,
208     /* PrimeCell ID */
209     0xd, 0xf0, 0x05, 0xb1
210 };
211 
212 /* Merge the IRQs from the two component devices.  */
213 static void sp804_set_irq(void *opaque, int irq, int level)
214 {
215     SP804State *s = (SP804State *)opaque;
216 
217     s->level[irq] = level;
218     qemu_set_irq(s->irq, s->level[0] || s->level[1]);
219 }
220 
221 static uint64_t sp804_read(void *opaque, hwaddr offset,
222                            unsigned size)
223 {
224     SP804State *s = (SP804State *)opaque;
225 
226     if (offset < 0x20) {
227         return arm_timer_read(s->timer[0], offset);
228     }
229     if (offset < 0x40) {
230         return arm_timer_read(s->timer[1], offset - 0x20);
231     }
232 
233     /* TimerPeriphID */
234     if (offset >= 0xfe0 && offset <= 0xffc) {
235         return sp804_ids[(offset - 0xfe0) >> 2];
236     }
237 
238     switch (offset) {
239     /* Integration Test control registers, which we won't support */
240     case 0xf00: /* TimerITCR */
241     case 0xf04: /* TimerITOP (strictly write only but..) */
242         qemu_log_mask(LOG_UNIMP,
243                       "%s: integration test registers unimplemented\n",
244                       __func__);
245         return 0;
246     }
247 
248     qemu_log_mask(LOG_GUEST_ERROR,
249                   "%s: Bad offset %x\n", __func__, (int)offset);
250     return 0;
251 }
252 
253 static void sp804_write(void *opaque, hwaddr offset,
254                         uint64_t value, unsigned size)
255 {
256     SP804State *s = (SP804State *)opaque;
257 
258     if (offset < 0x20) {
259         arm_timer_write(s->timer[0], offset, value);
260         return;
261     }
262 
263     if (offset < 0x40) {
264         arm_timer_write(s->timer[1], offset - 0x20, value);
265         return;
266     }
267 
268     /* Technically we could be writing to the Test Registers, but not likely */
269     qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %x\n",
270                   __func__, (int)offset);
271 }
272 
273 static const MemoryRegionOps sp804_ops = {
274     .read = sp804_read,
275     .write = sp804_write,
276     .endianness = DEVICE_NATIVE_ENDIAN,
277 };
278 
279 static const VMStateDescription vmstate_sp804 = {
280     .name = "sp804",
281     .version_id = 1,
282     .minimum_version_id = 1,
283     .fields = (VMStateField[]) {
284         VMSTATE_INT32_ARRAY(level, SP804State, 2),
285         VMSTATE_END_OF_LIST()
286     }
287 };
288 
289 static void sp804_init(Object *obj)
290 {
291     SP804State *s = SP804(obj);
292     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
293 
294     sysbus_init_irq(sbd, &s->irq);
295     memory_region_init_io(&s->iomem, obj, &sp804_ops, s,
296                           "sp804", 0x1000);
297     sysbus_init_mmio(sbd, &s->iomem);
298 }
299 
300 static void sp804_realize(DeviceState *dev, Error **errp)
301 {
302     SP804State *s = SP804(dev);
303 
304     s->timer[0] = arm_timer_init(s->freq0);
305     s->timer[1] = arm_timer_init(s->freq1);
306     s->timer[0]->irq = qemu_allocate_irq(sp804_set_irq, s, 0);
307     s->timer[1]->irq = qemu_allocate_irq(sp804_set_irq, s, 1);
308 }
309 
310 /* Integrator/CP timer module.  */
311 
312 #define TYPE_INTEGRATOR_PIT "integrator_pit"
313 #define INTEGRATOR_PIT(obj) \
314     OBJECT_CHECK(icp_pit_state, (obj), TYPE_INTEGRATOR_PIT)
315 
316 typedef struct {
317     SysBusDevice parent_obj;
318 
319     MemoryRegion iomem;
320     arm_timer_state *timer[3];
321 } icp_pit_state;
322 
323 static uint64_t icp_pit_read(void *opaque, hwaddr offset,
324                              unsigned size)
325 {
326     icp_pit_state *s = (icp_pit_state *)opaque;
327     int n;
328 
329     /* ??? Don't know the PrimeCell ID for this device.  */
330     n = offset >> 8;
331     if (n > 2) {
332         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
333         return 0;
334     }
335 
336     return arm_timer_read(s->timer[n], offset & 0xff);
337 }
338 
339 static void icp_pit_write(void *opaque, hwaddr offset,
340                           uint64_t value, unsigned size)
341 {
342     icp_pit_state *s = (icp_pit_state *)opaque;
343     int n;
344 
345     n = offset >> 8;
346     if (n > 2) {
347         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
348         return;
349     }
350 
351     arm_timer_write(s->timer[n], offset & 0xff, value);
352 }
353 
354 static const MemoryRegionOps icp_pit_ops = {
355     .read = icp_pit_read,
356     .write = icp_pit_write,
357     .endianness = DEVICE_NATIVE_ENDIAN,
358 };
359 
360 static void icp_pit_init(Object *obj)
361 {
362     icp_pit_state *s = INTEGRATOR_PIT(obj);
363     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
364 
365     /* Timer 0 runs at the system clock speed (40MHz).  */
366     s->timer[0] = arm_timer_init(40000000);
367     /* The other two timers run at 1MHz.  */
368     s->timer[1] = arm_timer_init(1000000);
369     s->timer[2] = arm_timer_init(1000000);
370 
371     sysbus_init_irq(dev, &s->timer[0]->irq);
372     sysbus_init_irq(dev, &s->timer[1]->irq);
373     sysbus_init_irq(dev, &s->timer[2]->irq);
374 
375     memory_region_init_io(&s->iomem, obj, &icp_pit_ops, s,
376                           "icp_pit", 0x1000);
377     sysbus_init_mmio(dev, &s->iomem);
378     /* This device has no state to save/restore.  The component timers will
379        save themselves.  */
380 }
381 
382 static const TypeInfo icp_pit_info = {
383     .name          = TYPE_INTEGRATOR_PIT,
384     .parent        = TYPE_SYS_BUS_DEVICE,
385     .instance_size = sizeof(icp_pit_state),
386     .instance_init = icp_pit_init,
387 };
388 
389 static Property sp804_properties[] = {
390     DEFINE_PROP_UINT32("freq0", SP804State, freq0, 1000000),
391     DEFINE_PROP_UINT32("freq1", SP804State, freq1, 1000000),
392     DEFINE_PROP_END_OF_LIST(),
393 };
394 
395 static void sp804_class_init(ObjectClass *klass, void *data)
396 {
397     DeviceClass *k = DEVICE_CLASS(klass);
398 
399     k->realize = sp804_realize;
400     k->props = sp804_properties;
401     k->vmsd = &vmstate_sp804;
402 }
403 
404 static const TypeInfo sp804_info = {
405     .name          = TYPE_SP804,
406     .parent        = TYPE_SYS_BUS_DEVICE,
407     .instance_size = sizeof(SP804State),
408     .instance_init = sp804_init,
409     .class_init    = sp804_class_init,
410 };
411 
412 static void arm_timer_register_types(void)
413 {
414     type_register_static(&icp_pit_info);
415     type_register_static(&sp804_info);
416 }
417 
418 type_init(arm_timer_register_types)
419