xref: /openbmc/qemu/hw/timer/arm_timer.c (revision d695918f)
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 = g_new0(arm_timer_state, 1);
180     s->freq = freq;
181     s->control = TIMER_CTRL_IE;
182 
183     s->timer = ptimer_init(arm_timer_tick, s, PTIMER_POLICY_LEGACY);
184     vmstate_register(NULL, VMSTATE_INSTANCE_ID_ANY, &vmstate_arm_timer, s);
185     return s;
186 }
187 
188 /*
189  * ARM PrimeCell SP804 dual timer module.
190  * Docs at
191  * https://developer.arm.com/documentation/ddi0271/latest/
192  */
193 
194 #define TYPE_SP804 "sp804"
195 OBJECT_DECLARE_SIMPLE_TYPE(SP804State, SP804)
196 
197 struct SP804State {
198     SysBusDevice parent_obj;
199 
200     MemoryRegion iomem;
201     arm_timer_state *timer[2];
202     uint32_t freq0, freq1;
203     int level[2];
204     qemu_irq irq;
205 };
206 
207 static const uint8_t sp804_ids[] = {
208     /* Timer ID */
209     0x04, 0x18, 0x14, 0,
210     /* PrimeCell ID */
211     0xd, 0xf0, 0x05, 0xb1
212 };
213 
214 /* Merge the IRQs from the two component devices.  */
215 static void sp804_set_irq(void *opaque, int irq, int level)
216 {
217     SP804State *s = (SP804State *)opaque;
218 
219     s->level[irq] = level;
220     qemu_set_irq(s->irq, s->level[0] || s->level[1]);
221 }
222 
223 static uint64_t sp804_read(void *opaque, hwaddr offset,
224                            unsigned size)
225 {
226     SP804State *s = (SP804State *)opaque;
227 
228     if (offset < 0x20) {
229         return arm_timer_read(s->timer[0], offset);
230     }
231     if (offset < 0x40) {
232         return arm_timer_read(s->timer[1], offset - 0x20);
233     }
234 
235     /* TimerPeriphID */
236     if (offset >= 0xfe0 && offset <= 0xffc) {
237         return sp804_ids[(offset - 0xfe0) >> 2];
238     }
239 
240     switch (offset) {
241     /* Integration Test control registers, which we won't support */
242     case 0xf00: /* TimerITCR */
243     case 0xf04: /* TimerITOP (strictly write only but..) */
244         qemu_log_mask(LOG_UNIMP,
245                       "%s: integration test registers unimplemented\n",
246                       __func__);
247         return 0;
248     }
249 
250     qemu_log_mask(LOG_GUEST_ERROR,
251                   "%s: Bad offset %x\n", __func__, (int)offset);
252     return 0;
253 }
254 
255 static void sp804_write(void *opaque, hwaddr offset,
256                         uint64_t value, unsigned size)
257 {
258     SP804State *s = (SP804State *)opaque;
259 
260     if (offset < 0x20) {
261         arm_timer_write(s->timer[0], offset, value);
262         return;
263     }
264 
265     if (offset < 0x40) {
266         arm_timer_write(s->timer[1], offset - 0x20, value);
267         return;
268     }
269 
270     /* Technically we could be writing to the Test Registers, but not likely */
271     qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %x\n",
272                   __func__, (int)offset);
273 }
274 
275 static const MemoryRegionOps sp804_ops = {
276     .read = sp804_read,
277     .write = sp804_write,
278     .endianness = DEVICE_NATIVE_ENDIAN,
279 };
280 
281 static const VMStateDescription vmstate_sp804 = {
282     .name = "sp804",
283     .version_id = 1,
284     .minimum_version_id = 1,
285     .fields = (VMStateField[]) {
286         VMSTATE_INT32_ARRAY(level, SP804State, 2),
287         VMSTATE_END_OF_LIST()
288     }
289 };
290 
291 static void sp804_init(Object *obj)
292 {
293     SP804State *s = SP804(obj);
294     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
295 
296     sysbus_init_irq(sbd, &s->irq);
297     memory_region_init_io(&s->iomem, obj, &sp804_ops, s,
298                           "sp804", 0x1000);
299     sysbus_init_mmio(sbd, &s->iomem);
300 }
301 
302 static void sp804_realize(DeviceState *dev, Error **errp)
303 {
304     SP804State *s = SP804(dev);
305 
306     s->timer[0] = arm_timer_init(s->freq0);
307     s->timer[1] = arm_timer_init(s->freq1);
308     s->timer[0]->irq = qemu_allocate_irq(sp804_set_irq, s, 0);
309     s->timer[1]->irq = qemu_allocate_irq(sp804_set_irq, s, 1);
310 }
311 
312 /* Integrator/CP timer module.  */
313 
314 #define TYPE_INTEGRATOR_PIT "integrator_pit"
315 OBJECT_DECLARE_SIMPLE_TYPE(icp_pit_state, INTEGRATOR_PIT)
316 
317 struct icp_pit_state {
318     SysBusDevice parent_obj;
319 
320     MemoryRegion iomem;
321     arm_timer_state *timer[3];
322 };
323 
324 static uint64_t icp_pit_read(void *opaque, hwaddr offset,
325                              unsigned size)
326 {
327     icp_pit_state *s = (icp_pit_state *)opaque;
328     int n;
329 
330     /* ??? Don't know the PrimeCell ID for this device.  */
331     n = offset >> 8;
332     if (n > 2) {
333         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
334         return 0;
335     }
336 
337     return arm_timer_read(s->timer[n], offset & 0xff);
338 }
339 
340 static void icp_pit_write(void *opaque, hwaddr offset,
341                           uint64_t value, unsigned size)
342 {
343     icp_pit_state *s = (icp_pit_state *)opaque;
344     int n;
345 
346     n = offset >> 8;
347     if (n > 2) {
348         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
349         return;
350     }
351 
352     arm_timer_write(s->timer[n], offset & 0xff, value);
353 }
354 
355 static const MemoryRegionOps icp_pit_ops = {
356     .read = icp_pit_read,
357     .write = icp_pit_write,
358     .endianness = DEVICE_NATIVE_ENDIAN,
359 };
360 
361 static void icp_pit_init(Object *obj)
362 {
363     icp_pit_state *s = INTEGRATOR_PIT(obj);
364     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
365 
366     /* Timer 0 runs at the system clock speed (40MHz).  */
367     s->timer[0] = arm_timer_init(40000000);
368     /* The other two timers run at 1MHz.  */
369     s->timer[1] = arm_timer_init(1000000);
370     s->timer[2] = arm_timer_init(1000000);
371 
372     sysbus_init_irq(dev, &s->timer[0]->irq);
373     sysbus_init_irq(dev, &s->timer[1]->irq);
374     sysbus_init_irq(dev, &s->timer[2]->irq);
375 
376     memory_region_init_io(&s->iomem, obj, &icp_pit_ops, s,
377                           "icp_pit", 0x1000);
378     sysbus_init_mmio(dev, &s->iomem);
379     /* This device has no state to save/restore.  The component timers will
380        save themselves.  */
381 }
382 
383 static const TypeInfo icp_pit_info = {
384     .name          = TYPE_INTEGRATOR_PIT,
385     .parent        = TYPE_SYS_BUS_DEVICE,
386     .instance_size = sizeof(icp_pit_state),
387     .instance_init = icp_pit_init,
388 };
389 
390 static Property sp804_properties[] = {
391     DEFINE_PROP_UINT32("freq0", SP804State, freq0, 1000000),
392     DEFINE_PROP_UINT32("freq1", SP804State, freq1, 1000000),
393     DEFINE_PROP_END_OF_LIST(),
394 };
395 
396 static void sp804_class_init(ObjectClass *klass, void *data)
397 {
398     DeviceClass *k = DEVICE_CLASS(klass);
399 
400     k->realize = sp804_realize;
401     device_class_set_props(k, sp804_properties);
402     k->vmsd = &vmstate_sp804;
403 }
404 
405 static const TypeInfo sp804_info = {
406     .name          = TYPE_SP804,
407     .parent        = TYPE_SYS_BUS_DEVICE,
408     .instance_size = sizeof(SP804State),
409     .instance_init = sp804_init,
410     .class_init    = sp804_class_init,
411 };
412 
413 static void arm_timer_register_types(void)
414 {
415     type_register_static(&icp_pit_info);
416     type_register_static(&sp804_info);
417 }
418 
419 type_init(arm_timer_register_types)
420