xref: /openbmc/qemu/hw/timer/arm_timer.c (revision a68694cd)
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 #include "qom/object.h"
20 
21 /* Common timer implementation.  */
22 
23 #define TIMER_CTRL_ONESHOT      (1 << 0)
24 #define TIMER_CTRL_32BIT        (1 << 1)
25 #define TIMER_CTRL_DIV1         (0 << 2)
26 #define TIMER_CTRL_DIV16        (1 << 2)
27 #define TIMER_CTRL_DIV256       (2 << 2)
28 #define TIMER_CTRL_IE           (1 << 5)
29 #define TIMER_CTRL_PERIODIC     (1 << 6)
30 #define TIMER_CTRL_ENABLE       (1 << 7)
31 
32 typedef struct {
33     ptimer_state *timer;
34     uint32_t control;
35     uint32_t limit;
36     int freq;
37     int int_level;
38     qemu_irq irq;
39 } arm_timer_state;
40 
41 /* Check all active timers, and schedule the next timer interrupt.  */
42 
43 static void arm_timer_update(arm_timer_state *s)
44 {
45     /* Update interrupts.  */
46     if (s->int_level && (s->control & TIMER_CTRL_IE)) {
47         qemu_irq_raise(s->irq);
48     } else {
49         qemu_irq_lower(s->irq);
50     }
51 }
52 
53 static uint32_t arm_timer_read(void *opaque, hwaddr offset)
54 {
55     arm_timer_state *s = (arm_timer_state *)opaque;
56 
57     switch (offset >> 2) {
58     case 0: /* TimerLoad */
59     case 6: /* TimerBGLoad */
60         return s->limit;
61     case 1: /* TimerValue */
62         return ptimer_get_count(s->timer);
63     case 2: /* TimerControl */
64         return s->control;
65     case 4: /* TimerRIS */
66         return s->int_level;
67     case 5: /* TimerMIS */
68         if ((s->control & TIMER_CTRL_IE) == 0)
69             return 0;
70         return s->int_level;
71     default:
72         qemu_log_mask(LOG_GUEST_ERROR,
73                       "%s: Bad offset %x\n", __func__, (int)offset);
74         return 0;
75     }
76 }
77 
78 /*
79  * Reset the timer limit after settings have changed.
80  * May only be called from inside a ptimer transaction block.
81  */
82 static void arm_timer_recalibrate(arm_timer_state *s, int reload)
83 {
84     uint32_t limit;
85 
86     if ((s->control & (TIMER_CTRL_PERIODIC | TIMER_CTRL_ONESHOT)) == 0) {
87         /* Free running.  */
88         if (s->control & TIMER_CTRL_32BIT)
89             limit = 0xffffffff;
90         else
91             limit = 0xffff;
92     } else {
93           /* Periodic.  */
94           limit = s->limit;
95     }
96     ptimer_set_limit(s->timer, limit, reload);
97 }
98 
99 static void arm_timer_write(void *opaque, hwaddr offset,
100                             uint32_t value)
101 {
102     arm_timer_state *s = (arm_timer_state *)opaque;
103     int freq;
104 
105     switch (offset >> 2) {
106     case 0: /* TimerLoad */
107         s->limit = value;
108         ptimer_transaction_begin(s->timer);
109         arm_timer_recalibrate(s, 1);
110         ptimer_transaction_commit(s->timer);
111         break;
112     case 1: /* TimerValue */
113         /* ??? Linux seems to want to write to this readonly register.
114            Ignore it.  */
115         break;
116     case 2: /* TimerControl */
117         ptimer_transaction_begin(s->timer);
118         if (s->control & TIMER_CTRL_ENABLE) {
119             /* Pause the timer if it is running.  This may cause some
120                inaccuracy dure to rounding, but avoids a whole lot of other
121                messyness.  */
122             ptimer_stop(s->timer);
123         }
124         s->control = value;
125         freq = s->freq;
126         /* ??? Need to recalculate expiry time after changing divisor.  */
127         switch ((value >> 2) & 3) {
128         case 1: freq >>= 4; break;
129         case 2: freq >>= 8; break;
130         }
131         arm_timer_recalibrate(s, s->control & TIMER_CTRL_ENABLE);
132         ptimer_set_freq(s->timer, freq);
133         if (s->control & TIMER_CTRL_ENABLE) {
134             /* Restart the timer if still enabled.  */
135             ptimer_run(s->timer, (s->control & TIMER_CTRL_ONESHOT) != 0);
136         }
137         ptimer_transaction_commit(s->timer);
138         break;
139     case 3: /* TimerIntClr */
140         s->int_level = 0;
141         break;
142     case 6: /* TimerBGLoad */
143         s->limit = value;
144         ptimer_transaction_begin(s->timer);
145         arm_timer_recalibrate(s, 0);
146         ptimer_transaction_commit(s->timer);
147         break;
148     default:
149         qemu_log_mask(LOG_GUEST_ERROR,
150                       "%s: Bad offset %x\n", __func__, (int)offset);
151     }
152     arm_timer_update(s);
153 }
154 
155 static void arm_timer_tick(void *opaque)
156 {
157     arm_timer_state *s = (arm_timer_state *)opaque;
158     s->int_level = 1;
159     arm_timer_update(s);
160 }
161 
162 static const VMStateDescription vmstate_arm_timer = {
163     .name = "arm_timer",
164     .version_id = 1,
165     .minimum_version_id = 1,
166     .fields = (VMStateField[]) {
167         VMSTATE_UINT32(control, arm_timer_state),
168         VMSTATE_UINT32(limit, arm_timer_state),
169         VMSTATE_INT32(int_level, arm_timer_state),
170         VMSTATE_PTIMER(timer, arm_timer_state),
171         VMSTATE_END_OF_LIST()
172     }
173 };
174 
175 static arm_timer_state *arm_timer_init(uint32_t freq)
176 {
177     arm_timer_state *s;
178 
179     s = (arm_timer_state *)g_malloc0(sizeof(arm_timer_state));
180     s->freq = freq;
181     s->control = TIMER_CTRL_IE;
182 
183     s->timer = ptimer_init(arm_timer_tick, s, PTIMER_POLICY_DEFAULT);
184     vmstate_register(NULL, VMSTATE_INSTANCE_ID_ANY, &vmstate_arm_timer, s);
185     return s;
186 }
187 
188 /* ARM PrimeCell SP804 dual timer module.
189  * Docs at
190  * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0271d/index.html
191 */
192 
193 #define TYPE_SP804 "sp804"
194 typedef struct SP804State SP804State;
195 DECLARE_INSTANCE_CHECKER(SP804State, SP804,
196                          TYPE_SP804)
197 
198 struct SP804State {
199     SysBusDevice parent_obj;
200 
201     MemoryRegion iomem;
202     arm_timer_state *timer[2];
203     uint32_t freq0, freq1;
204     int level[2];
205     qemu_irq irq;
206 };
207 
208 static const uint8_t sp804_ids[] = {
209     /* Timer ID */
210     0x04, 0x18, 0x14, 0,
211     /* PrimeCell ID */
212     0xd, 0xf0, 0x05, 0xb1
213 };
214 
215 /* Merge the IRQs from the two component devices.  */
216 static void sp804_set_irq(void *opaque, int irq, int level)
217 {
218     SP804State *s = (SP804State *)opaque;
219 
220     s->level[irq] = level;
221     qemu_set_irq(s->irq, s->level[0] || s->level[1]);
222 }
223 
224 static uint64_t sp804_read(void *opaque, hwaddr offset,
225                            unsigned size)
226 {
227     SP804State *s = (SP804State *)opaque;
228 
229     if (offset < 0x20) {
230         return arm_timer_read(s->timer[0], offset);
231     }
232     if (offset < 0x40) {
233         return arm_timer_read(s->timer[1], offset - 0x20);
234     }
235 
236     /* TimerPeriphID */
237     if (offset >= 0xfe0 && offset <= 0xffc) {
238         return sp804_ids[(offset - 0xfe0) >> 2];
239     }
240 
241     switch (offset) {
242     /* Integration Test control registers, which we won't support */
243     case 0xf00: /* TimerITCR */
244     case 0xf04: /* TimerITOP (strictly write only but..) */
245         qemu_log_mask(LOG_UNIMP,
246                       "%s: integration test registers unimplemented\n",
247                       __func__);
248         return 0;
249     }
250 
251     qemu_log_mask(LOG_GUEST_ERROR,
252                   "%s: Bad offset %x\n", __func__, (int)offset);
253     return 0;
254 }
255 
256 static void sp804_write(void *opaque, hwaddr offset,
257                         uint64_t value, unsigned size)
258 {
259     SP804State *s = (SP804State *)opaque;
260 
261     if (offset < 0x20) {
262         arm_timer_write(s->timer[0], offset, value);
263         return;
264     }
265 
266     if (offset < 0x40) {
267         arm_timer_write(s->timer[1], offset - 0x20, value);
268         return;
269     }
270 
271     /* Technically we could be writing to the Test Registers, but not likely */
272     qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %x\n",
273                   __func__, (int)offset);
274 }
275 
276 static const MemoryRegionOps sp804_ops = {
277     .read = sp804_read,
278     .write = sp804_write,
279     .endianness = DEVICE_NATIVE_ENDIAN,
280 };
281 
282 static const VMStateDescription vmstate_sp804 = {
283     .name = "sp804",
284     .version_id = 1,
285     .minimum_version_id = 1,
286     .fields = (VMStateField[]) {
287         VMSTATE_INT32_ARRAY(level, SP804State, 2),
288         VMSTATE_END_OF_LIST()
289     }
290 };
291 
292 static void sp804_init(Object *obj)
293 {
294     SP804State *s = SP804(obj);
295     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
296 
297     sysbus_init_irq(sbd, &s->irq);
298     memory_region_init_io(&s->iomem, obj, &sp804_ops, s,
299                           "sp804", 0x1000);
300     sysbus_init_mmio(sbd, &s->iomem);
301 }
302 
303 static void sp804_realize(DeviceState *dev, Error **errp)
304 {
305     SP804State *s = SP804(dev);
306 
307     s->timer[0] = arm_timer_init(s->freq0);
308     s->timer[1] = arm_timer_init(s->freq1);
309     s->timer[0]->irq = qemu_allocate_irq(sp804_set_irq, s, 0);
310     s->timer[1]->irq = qemu_allocate_irq(sp804_set_irq, s, 1);
311 }
312 
313 /* Integrator/CP timer module.  */
314 
315 #define TYPE_INTEGRATOR_PIT "integrator_pit"
316 typedef struct icp_pit_state icp_pit_state;
317 DECLARE_INSTANCE_CHECKER(icp_pit_state, INTEGRATOR_PIT,
318                          TYPE_INTEGRATOR_PIT)
319 
320 struct icp_pit_state {
321     SysBusDevice parent_obj;
322 
323     MemoryRegion iomem;
324     arm_timer_state *timer[3];
325 };
326 
327 static uint64_t icp_pit_read(void *opaque, hwaddr offset,
328                              unsigned size)
329 {
330     icp_pit_state *s = (icp_pit_state *)opaque;
331     int n;
332 
333     /* ??? Don't know the PrimeCell ID for this device.  */
334     n = offset >> 8;
335     if (n > 2) {
336         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
337         return 0;
338     }
339 
340     return arm_timer_read(s->timer[n], offset & 0xff);
341 }
342 
343 static void icp_pit_write(void *opaque, hwaddr offset,
344                           uint64_t value, unsigned size)
345 {
346     icp_pit_state *s = (icp_pit_state *)opaque;
347     int n;
348 
349     n = offset >> 8;
350     if (n > 2) {
351         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
352         return;
353     }
354 
355     arm_timer_write(s->timer[n], offset & 0xff, value);
356 }
357 
358 static const MemoryRegionOps icp_pit_ops = {
359     .read = icp_pit_read,
360     .write = icp_pit_write,
361     .endianness = DEVICE_NATIVE_ENDIAN,
362 };
363 
364 static void icp_pit_init(Object *obj)
365 {
366     icp_pit_state *s = INTEGRATOR_PIT(obj);
367     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
368 
369     /* Timer 0 runs at the system clock speed (40MHz).  */
370     s->timer[0] = arm_timer_init(40000000);
371     /* The other two timers run at 1MHz.  */
372     s->timer[1] = arm_timer_init(1000000);
373     s->timer[2] = arm_timer_init(1000000);
374 
375     sysbus_init_irq(dev, &s->timer[0]->irq);
376     sysbus_init_irq(dev, &s->timer[1]->irq);
377     sysbus_init_irq(dev, &s->timer[2]->irq);
378 
379     memory_region_init_io(&s->iomem, obj, &icp_pit_ops, s,
380                           "icp_pit", 0x1000);
381     sysbus_init_mmio(dev, &s->iomem);
382     /* This device has no state to save/restore.  The component timers will
383        save themselves.  */
384 }
385 
386 static const TypeInfo icp_pit_info = {
387     .name          = TYPE_INTEGRATOR_PIT,
388     .parent        = TYPE_SYS_BUS_DEVICE,
389     .instance_size = sizeof(icp_pit_state),
390     .instance_init = icp_pit_init,
391 };
392 
393 static Property sp804_properties[] = {
394     DEFINE_PROP_UINT32("freq0", SP804State, freq0, 1000000),
395     DEFINE_PROP_UINT32("freq1", SP804State, freq1, 1000000),
396     DEFINE_PROP_END_OF_LIST(),
397 };
398 
399 static void sp804_class_init(ObjectClass *klass, void *data)
400 {
401     DeviceClass *k = DEVICE_CLASS(klass);
402 
403     k->realize = sp804_realize;
404     device_class_set_props(k, sp804_properties);
405     k->vmsd = &vmstate_sp804;
406 }
407 
408 static const TypeInfo sp804_info = {
409     .name          = TYPE_SP804,
410     .parent        = TYPE_SYS_BUS_DEVICE,
411     .instance_size = sizeof(SP804State),
412     .instance_init = sp804_init,
413     .class_init    = sp804_class_init,
414 };
415 
416 static void arm_timer_register_types(void)
417 {
418     type_register_static(&icp_pit_info);
419     type_register_static(&sp804_info);
420 }
421 
422 type_init(arm_timer_register_types)
423