xref: /openbmc/qemu/hw/timer/arm_timer.c (revision 64552b6b)
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 "qemu/timer.h"
13 #include "hw/qdev.h"
14 #include "hw/irq.h"
15 #include "hw/ptimer.h"
16 #include "qemu/main-loop.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 /* Reset the timer limit after settings have changed.  */
78 static void arm_timer_recalibrate(arm_timer_state *s, int reload)
79 {
80     uint32_t limit;
81 
82     if ((s->control & (TIMER_CTRL_PERIODIC | TIMER_CTRL_ONESHOT)) == 0) {
83         /* Free running.  */
84         if (s->control & TIMER_CTRL_32BIT)
85             limit = 0xffffffff;
86         else
87             limit = 0xffff;
88     } else {
89           /* Periodic.  */
90           limit = s->limit;
91     }
92     ptimer_set_limit(s->timer, limit, reload);
93 }
94 
95 static void arm_timer_write(void *opaque, hwaddr offset,
96                             uint32_t value)
97 {
98     arm_timer_state *s = (arm_timer_state *)opaque;
99     int freq;
100 
101     switch (offset >> 2) {
102     case 0: /* TimerLoad */
103         s->limit = value;
104         arm_timer_recalibrate(s, 1);
105         break;
106     case 1: /* TimerValue */
107         /* ??? Linux seems to want to write to this readonly register.
108            Ignore it.  */
109         break;
110     case 2: /* TimerControl */
111         if (s->control & TIMER_CTRL_ENABLE) {
112             /* Pause the timer if it is running.  This may cause some
113                inaccuracy dure to rounding, but avoids a whole lot of other
114                messyness.  */
115             ptimer_stop(s->timer);
116         }
117         s->control = value;
118         freq = s->freq;
119         /* ??? Need to recalculate expiry time after changing divisor.  */
120         switch ((value >> 2) & 3) {
121         case 1: freq >>= 4; break;
122         case 2: freq >>= 8; break;
123         }
124         arm_timer_recalibrate(s, s->control & TIMER_CTRL_ENABLE);
125         ptimer_set_freq(s->timer, freq);
126         if (s->control & TIMER_CTRL_ENABLE) {
127             /* Restart the timer if still enabled.  */
128             ptimer_run(s->timer, (s->control & TIMER_CTRL_ONESHOT) != 0);
129         }
130         break;
131     case 3: /* TimerIntClr */
132         s->int_level = 0;
133         break;
134     case 6: /* TimerBGLoad */
135         s->limit = value;
136         arm_timer_recalibrate(s, 0);
137         break;
138     default:
139         qemu_log_mask(LOG_GUEST_ERROR,
140                       "%s: Bad offset %x\n", __func__, (int)offset);
141     }
142     arm_timer_update(s);
143 }
144 
145 static void arm_timer_tick(void *opaque)
146 {
147     arm_timer_state *s = (arm_timer_state *)opaque;
148     s->int_level = 1;
149     arm_timer_update(s);
150 }
151 
152 static const VMStateDescription vmstate_arm_timer = {
153     .name = "arm_timer",
154     .version_id = 1,
155     .minimum_version_id = 1,
156     .fields = (VMStateField[]) {
157         VMSTATE_UINT32(control, arm_timer_state),
158         VMSTATE_UINT32(limit, arm_timer_state),
159         VMSTATE_INT32(int_level, arm_timer_state),
160         VMSTATE_PTIMER(timer, arm_timer_state),
161         VMSTATE_END_OF_LIST()
162     }
163 };
164 
165 static arm_timer_state *arm_timer_init(uint32_t freq)
166 {
167     arm_timer_state *s;
168     QEMUBH *bh;
169 
170     s = (arm_timer_state *)g_malloc0(sizeof(arm_timer_state));
171     s->freq = freq;
172     s->control = TIMER_CTRL_IE;
173 
174     bh = qemu_bh_new(arm_timer_tick, s);
175     s->timer = ptimer_init(bh, PTIMER_POLICY_DEFAULT);
176     vmstate_register(NULL, -1, &vmstate_arm_timer, s);
177     return s;
178 }
179 
180 /* ARM PrimeCell SP804 dual timer module.
181  * Docs at
182  * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0271d/index.html
183 */
184 
185 #define TYPE_SP804 "sp804"
186 #define SP804(obj) OBJECT_CHECK(SP804State, (obj), TYPE_SP804)
187 
188 typedef struct SP804State {
189     SysBusDevice parent_obj;
190 
191     MemoryRegion iomem;
192     arm_timer_state *timer[2];
193     uint32_t freq0, freq1;
194     int level[2];
195     qemu_irq irq;
196 } SP804State;
197 
198 static const uint8_t sp804_ids[] = {
199     /* Timer ID */
200     0x04, 0x18, 0x14, 0,
201     /* PrimeCell ID */
202     0xd, 0xf0, 0x05, 0xb1
203 };
204 
205 /* Merge the IRQs from the two component devices.  */
206 static void sp804_set_irq(void *opaque, int irq, int level)
207 {
208     SP804State *s = (SP804State *)opaque;
209 
210     s->level[irq] = level;
211     qemu_set_irq(s->irq, s->level[0] || s->level[1]);
212 }
213 
214 static uint64_t sp804_read(void *opaque, hwaddr offset,
215                            unsigned size)
216 {
217     SP804State *s = (SP804State *)opaque;
218 
219     if (offset < 0x20) {
220         return arm_timer_read(s->timer[0], offset);
221     }
222     if (offset < 0x40) {
223         return arm_timer_read(s->timer[1], offset - 0x20);
224     }
225 
226     /* TimerPeriphID */
227     if (offset >= 0xfe0 && offset <= 0xffc) {
228         return sp804_ids[(offset - 0xfe0) >> 2];
229     }
230 
231     switch (offset) {
232     /* Integration Test control registers, which we won't support */
233     case 0xf00: /* TimerITCR */
234     case 0xf04: /* TimerITOP (strictly write only but..) */
235         qemu_log_mask(LOG_UNIMP,
236                       "%s: integration test registers unimplemented\n",
237                       __func__);
238         return 0;
239     }
240 
241     qemu_log_mask(LOG_GUEST_ERROR,
242                   "%s: Bad offset %x\n", __func__, (int)offset);
243     return 0;
244 }
245 
246 static void sp804_write(void *opaque, hwaddr offset,
247                         uint64_t value, unsigned size)
248 {
249     SP804State *s = (SP804State *)opaque;
250 
251     if (offset < 0x20) {
252         arm_timer_write(s->timer[0], offset, value);
253         return;
254     }
255 
256     if (offset < 0x40) {
257         arm_timer_write(s->timer[1], offset - 0x20, value);
258         return;
259     }
260 
261     /* Technically we could be writing to the Test Registers, but not likely */
262     qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %x\n",
263                   __func__, (int)offset);
264 }
265 
266 static const MemoryRegionOps sp804_ops = {
267     .read = sp804_read,
268     .write = sp804_write,
269     .endianness = DEVICE_NATIVE_ENDIAN,
270 };
271 
272 static const VMStateDescription vmstate_sp804 = {
273     .name = "sp804",
274     .version_id = 1,
275     .minimum_version_id = 1,
276     .fields = (VMStateField[]) {
277         VMSTATE_INT32_ARRAY(level, SP804State, 2),
278         VMSTATE_END_OF_LIST()
279     }
280 };
281 
282 static void sp804_init(Object *obj)
283 {
284     SP804State *s = SP804(obj);
285     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
286 
287     sysbus_init_irq(sbd, &s->irq);
288     memory_region_init_io(&s->iomem, obj, &sp804_ops, s,
289                           "sp804", 0x1000);
290     sysbus_init_mmio(sbd, &s->iomem);
291 }
292 
293 static void sp804_realize(DeviceState *dev, Error **errp)
294 {
295     SP804State *s = SP804(dev);
296 
297     s->timer[0] = arm_timer_init(s->freq0);
298     s->timer[1] = arm_timer_init(s->freq1);
299     s->timer[0]->irq = qemu_allocate_irq(sp804_set_irq, s, 0);
300     s->timer[1]->irq = qemu_allocate_irq(sp804_set_irq, s, 1);
301 }
302 
303 /* Integrator/CP timer module.  */
304 
305 #define TYPE_INTEGRATOR_PIT "integrator_pit"
306 #define INTEGRATOR_PIT(obj) \
307     OBJECT_CHECK(icp_pit_state, (obj), TYPE_INTEGRATOR_PIT)
308 
309 typedef struct {
310     SysBusDevice parent_obj;
311 
312     MemoryRegion iomem;
313     arm_timer_state *timer[3];
314 } icp_pit_state;
315 
316 static uint64_t icp_pit_read(void *opaque, hwaddr offset,
317                              unsigned size)
318 {
319     icp_pit_state *s = (icp_pit_state *)opaque;
320     int n;
321 
322     /* ??? Don't know the PrimeCell ID for this device.  */
323     n = offset >> 8;
324     if (n > 2) {
325         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
326         return 0;
327     }
328 
329     return arm_timer_read(s->timer[n], offset & 0xff);
330 }
331 
332 static void icp_pit_write(void *opaque, hwaddr offset,
333                           uint64_t value, unsigned size)
334 {
335     icp_pit_state *s = (icp_pit_state *)opaque;
336     int n;
337 
338     n = offset >> 8;
339     if (n > 2) {
340         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
341         return;
342     }
343 
344     arm_timer_write(s->timer[n], offset & 0xff, value);
345 }
346 
347 static const MemoryRegionOps icp_pit_ops = {
348     .read = icp_pit_read,
349     .write = icp_pit_write,
350     .endianness = DEVICE_NATIVE_ENDIAN,
351 };
352 
353 static void icp_pit_init(Object *obj)
354 {
355     icp_pit_state *s = INTEGRATOR_PIT(obj);
356     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
357 
358     /* Timer 0 runs at the system clock speed (40MHz).  */
359     s->timer[0] = arm_timer_init(40000000);
360     /* The other two timers run at 1MHz.  */
361     s->timer[1] = arm_timer_init(1000000);
362     s->timer[2] = arm_timer_init(1000000);
363 
364     sysbus_init_irq(dev, &s->timer[0]->irq);
365     sysbus_init_irq(dev, &s->timer[1]->irq);
366     sysbus_init_irq(dev, &s->timer[2]->irq);
367 
368     memory_region_init_io(&s->iomem, obj, &icp_pit_ops, s,
369                           "icp_pit", 0x1000);
370     sysbus_init_mmio(dev, &s->iomem);
371     /* This device has no state to save/restore.  The component timers will
372        save themselves.  */
373 }
374 
375 static const TypeInfo icp_pit_info = {
376     .name          = TYPE_INTEGRATOR_PIT,
377     .parent        = TYPE_SYS_BUS_DEVICE,
378     .instance_size = sizeof(icp_pit_state),
379     .instance_init = icp_pit_init,
380 };
381 
382 static Property sp804_properties[] = {
383     DEFINE_PROP_UINT32("freq0", SP804State, freq0, 1000000),
384     DEFINE_PROP_UINT32("freq1", SP804State, freq1, 1000000),
385     DEFINE_PROP_END_OF_LIST(),
386 };
387 
388 static void sp804_class_init(ObjectClass *klass, void *data)
389 {
390     DeviceClass *k = DEVICE_CLASS(klass);
391 
392     k->realize = sp804_realize;
393     k->props = sp804_properties;
394     k->vmsd = &vmstate_sp804;
395 }
396 
397 static const TypeInfo sp804_info = {
398     .name          = TYPE_SP804,
399     .parent        = TYPE_SYS_BUS_DEVICE,
400     .instance_size = sizeof(SP804State),
401     .instance_init = sp804_init,
402     .class_init    = sp804_class_init,
403 };
404 
405 static void arm_timer_register_types(void)
406 {
407     type_register_static(&icp_pit_info);
408     type_register_static(&sp804_info);
409 }
410 
411 type_init(arm_timer_register_types)
412