xref: /openbmc/qemu/hw/timer/arm_timer.c (revision 59a3a1c0)
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/main-loop.h"
18 #include "qemu/module.h"
19 #include "qemu/log.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 /* Reset the timer limit after settings have changed.  */
79 static void arm_timer_recalibrate(arm_timer_state *s, int reload)
80 {
81     uint32_t limit;
82 
83     if ((s->control & (TIMER_CTRL_PERIODIC | TIMER_CTRL_ONESHOT)) == 0) {
84         /* Free running.  */
85         if (s->control & TIMER_CTRL_32BIT)
86             limit = 0xffffffff;
87         else
88             limit = 0xffff;
89     } else {
90           /* Periodic.  */
91           limit = s->limit;
92     }
93     ptimer_set_limit(s->timer, limit, reload);
94 }
95 
96 static void arm_timer_write(void *opaque, hwaddr offset,
97                             uint32_t value)
98 {
99     arm_timer_state *s = (arm_timer_state *)opaque;
100     int freq;
101 
102     switch (offset >> 2) {
103     case 0: /* TimerLoad */
104         s->limit = value;
105         arm_timer_recalibrate(s, 1);
106         break;
107     case 1: /* TimerValue */
108         /* ??? Linux seems to want to write to this readonly register.
109            Ignore it.  */
110         break;
111     case 2: /* TimerControl */
112         if (s->control & TIMER_CTRL_ENABLE) {
113             /* Pause the timer if it is running.  This may cause some
114                inaccuracy dure to rounding, but avoids a whole lot of other
115                messyness.  */
116             ptimer_stop(s->timer);
117         }
118         s->control = value;
119         freq = s->freq;
120         /* ??? Need to recalculate expiry time after changing divisor.  */
121         switch ((value >> 2) & 3) {
122         case 1: freq >>= 4; break;
123         case 2: freq >>= 8; break;
124         }
125         arm_timer_recalibrate(s, s->control & TIMER_CTRL_ENABLE);
126         ptimer_set_freq(s->timer, freq);
127         if (s->control & TIMER_CTRL_ENABLE) {
128             /* Restart the timer if still enabled.  */
129             ptimer_run(s->timer, (s->control & TIMER_CTRL_ONESHOT) != 0);
130         }
131         break;
132     case 3: /* TimerIntClr */
133         s->int_level = 0;
134         break;
135     case 6: /* TimerBGLoad */
136         s->limit = value;
137         arm_timer_recalibrate(s, 0);
138         break;
139     default:
140         qemu_log_mask(LOG_GUEST_ERROR,
141                       "%s: Bad offset %x\n", __func__, (int)offset);
142     }
143     arm_timer_update(s);
144 }
145 
146 static void arm_timer_tick(void *opaque)
147 {
148     arm_timer_state *s = (arm_timer_state *)opaque;
149     s->int_level = 1;
150     arm_timer_update(s);
151 }
152 
153 static const VMStateDescription vmstate_arm_timer = {
154     .name = "arm_timer",
155     .version_id = 1,
156     .minimum_version_id = 1,
157     .fields = (VMStateField[]) {
158         VMSTATE_UINT32(control, arm_timer_state),
159         VMSTATE_UINT32(limit, arm_timer_state),
160         VMSTATE_INT32(int_level, arm_timer_state),
161         VMSTATE_PTIMER(timer, arm_timer_state),
162         VMSTATE_END_OF_LIST()
163     }
164 };
165 
166 static arm_timer_state *arm_timer_init(uint32_t freq)
167 {
168     arm_timer_state *s;
169     QEMUBH *bh;
170 
171     s = (arm_timer_state *)g_malloc0(sizeof(arm_timer_state));
172     s->freq = freq;
173     s->control = TIMER_CTRL_IE;
174 
175     bh = qemu_bh_new(arm_timer_tick, s);
176     s->timer = ptimer_init(bh, PTIMER_POLICY_DEFAULT);
177     vmstate_register(NULL, -1, &vmstate_arm_timer, s);
178     return s;
179 }
180 
181 /* ARM PrimeCell SP804 dual timer module.
182  * Docs at
183  * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0271d/index.html
184 */
185 
186 #define TYPE_SP804 "sp804"
187 #define SP804(obj) OBJECT_CHECK(SP804State, (obj), TYPE_SP804)
188 
189 typedef struct SP804State {
190     SysBusDevice parent_obj;
191 
192     MemoryRegion iomem;
193     arm_timer_state *timer[2];
194     uint32_t freq0, freq1;
195     int level[2];
196     qemu_irq irq;
197 } SP804State;
198 
199 static const uint8_t sp804_ids[] = {
200     /* Timer ID */
201     0x04, 0x18, 0x14, 0,
202     /* PrimeCell ID */
203     0xd, 0xf0, 0x05, 0xb1
204 };
205 
206 /* Merge the IRQs from the two component devices.  */
207 static void sp804_set_irq(void *opaque, int irq, int level)
208 {
209     SP804State *s = (SP804State *)opaque;
210 
211     s->level[irq] = level;
212     qemu_set_irq(s->irq, s->level[0] || s->level[1]);
213 }
214 
215 static uint64_t sp804_read(void *opaque, hwaddr offset,
216                            unsigned size)
217 {
218     SP804State *s = (SP804State *)opaque;
219 
220     if (offset < 0x20) {
221         return arm_timer_read(s->timer[0], offset);
222     }
223     if (offset < 0x40) {
224         return arm_timer_read(s->timer[1], offset - 0x20);
225     }
226 
227     /* TimerPeriphID */
228     if (offset >= 0xfe0 && offset <= 0xffc) {
229         return sp804_ids[(offset - 0xfe0) >> 2];
230     }
231 
232     switch (offset) {
233     /* Integration Test control registers, which we won't support */
234     case 0xf00: /* TimerITCR */
235     case 0xf04: /* TimerITOP (strictly write only but..) */
236         qemu_log_mask(LOG_UNIMP,
237                       "%s: integration test registers unimplemented\n",
238                       __func__);
239         return 0;
240     }
241 
242     qemu_log_mask(LOG_GUEST_ERROR,
243                   "%s: Bad offset %x\n", __func__, (int)offset);
244     return 0;
245 }
246 
247 static void sp804_write(void *opaque, hwaddr offset,
248                         uint64_t value, unsigned size)
249 {
250     SP804State *s = (SP804State *)opaque;
251 
252     if (offset < 0x20) {
253         arm_timer_write(s->timer[0], offset, value);
254         return;
255     }
256 
257     if (offset < 0x40) {
258         arm_timer_write(s->timer[1], offset - 0x20, value);
259         return;
260     }
261 
262     /* Technically we could be writing to the Test Registers, but not likely */
263     qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %x\n",
264                   __func__, (int)offset);
265 }
266 
267 static const MemoryRegionOps sp804_ops = {
268     .read = sp804_read,
269     .write = sp804_write,
270     .endianness = DEVICE_NATIVE_ENDIAN,
271 };
272 
273 static const VMStateDescription vmstate_sp804 = {
274     .name = "sp804",
275     .version_id = 1,
276     .minimum_version_id = 1,
277     .fields = (VMStateField[]) {
278         VMSTATE_INT32_ARRAY(level, SP804State, 2),
279         VMSTATE_END_OF_LIST()
280     }
281 };
282 
283 static void sp804_init(Object *obj)
284 {
285     SP804State *s = SP804(obj);
286     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
287 
288     sysbus_init_irq(sbd, &s->irq);
289     memory_region_init_io(&s->iomem, obj, &sp804_ops, s,
290                           "sp804", 0x1000);
291     sysbus_init_mmio(sbd, &s->iomem);
292 }
293 
294 static void sp804_realize(DeviceState *dev, Error **errp)
295 {
296     SP804State *s = SP804(dev);
297 
298     s->timer[0] = arm_timer_init(s->freq0);
299     s->timer[1] = arm_timer_init(s->freq1);
300     s->timer[0]->irq = qemu_allocate_irq(sp804_set_irq, s, 0);
301     s->timer[1]->irq = qemu_allocate_irq(sp804_set_irq, s, 1);
302 }
303 
304 /* Integrator/CP timer module.  */
305 
306 #define TYPE_INTEGRATOR_PIT "integrator_pit"
307 #define INTEGRATOR_PIT(obj) \
308     OBJECT_CHECK(icp_pit_state, (obj), TYPE_INTEGRATOR_PIT)
309 
310 typedef struct {
311     SysBusDevice parent_obj;
312 
313     MemoryRegion iomem;
314     arm_timer_state *timer[3];
315 } icp_pit_state;
316 
317 static uint64_t icp_pit_read(void *opaque, hwaddr offset,
318                              unsigned size)
319 {
320     icp_pit_state *s = (icp_pit_state *)opaque;
321     int n;
322 
323     /* ??? Don't know the PrimeCell ID for this device.  */
324     n = offset >> 8;
325     if (n > 2) {
326         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
327         return 0;
328     }
329 
330     return arm_timer_read(s->timer[n], offset & 0xff);
331 }
332 
333 static void icp_pit_write(void *opaque, hwaddr offset,
334                           uint64_t value, unsigned size)
335 {
336     icp_pit_state *s = (icp_pit_state *)opaque;
337     int n;
338 
339     n = offset >> 8;
340     if (n > 2) {
341         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
342         return;
343     }
344 
345     arm_timer_write(s->timer[n], offset & 0xff, value);
346 }
347 
348 static const MemoryRegionOps icp_pit_ops = {
349     .read = icp_pit_read,
350     .write = icp_pit_write,
351     .endianness = DEVICE_NATIVE_ENDIAN,
352 };
353 
354 static void icp_pit_init(Object *obj)
355 {
356     icp_pit_state *s = INTEGRATOR_PIT(obj);
357     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
358 
359     /* Timer 0 runs at the system clock speed (40MHz).  */
360     s->timer[0] = arm_timer_init(40000000);
361     /* The other two timers run at 1MHz.  */
362     s->timer[1] = arm_timer_init(1000000);
363     s->timer[2] = arm_timer_init(1000000);
364 
365     sysbus_init_irq(dev, &s->timer[0]->irq);
366     sysbus_init_irq(dev, &s->timer[1]->irq);
367     sysbus_init_irq(dev, &s->timer[2]->irq);
368 
369     memory_region_init_io(&s->iomem, obj, &icp_pit_ops, s,
370                           "icp_pit", 0x1000);
371     sysbus_init_mmio(dev, &s->iomem);
372     /* This device has no state to save/restore.  The component timers will
373        save themselves.  */
374 }
375 
376 static const TypeInfo icp_pit_info = {
377     .name          = TYPE_INTEGRATOR_PIT,
378     .parent        = TYPE_SYS_BUS_DEVICE,
379     .instance_size = sizeof(icp_pit_state),
380     .instance_init = icp_pit_init,
381 };
382 
383 static Property sp804_properties[] = {
384     DEFINE_PROP_UINT32("freq0", SP804State, freq0, 1000000),
385     DEFINE_PROP_UINT32("freq1", SP804State, freq1, 1000000),
386     DEFINE_PROP_END_OF_LIST(),
387 };
388 
389 static void sp804_class_init(ObjectClass *klass, void *data)
390 {
391     DeviceClass *k = DEVICE_CLASS(klass);
392 
393     k->realize = sp804_realize;
394     k->props = sp804_properties;
395     k->vmsd = &vmstate_sp804;
396 }
397 
398 static const TypeInfo sp804_info = {
399     .name          = TYPE_SP804,
400     .parent        = TYPE_SYS_BUS_DEVICE,
401     .instance_size = sizeof(SP804State),
402     .instance_init = sp804_init,
403     .class_init    = sp804_class_init,
404 };
405 
406 static void arm_timer_register_types(void)
407 {
408     type_register_static(&icp_pit_info);
409     type_register_static(&sp804_info);
410 }
411 
412 type_init(arm_timer_register_types)
413