xref: /openbmc/qemu/hw/timer/arm_timer.c (revision 9884abee)
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 "qemu-common.h"
14 #include "hw/qdev.h"
15 #include "hw/ptimer.h"
16 #include "qemu/main-loop.h"
17 
18 /* Common timer implementation.  */
19 
20 #define TIMER_CTRL_ONESHOT      (1 << 0)
21 #define TIMER_CTRL_32BIT        (1 << 1)
22 #define TIMER_CTRL_DIV1         (0 << 2)
23 #define TIMER_CTRL_DIV16        (1 << 2)
24 #define TIMER_CTRL_DIV256       (2 << 2)
25 #define TIMER_CTRL_IE           (1 << 5)
26 #define TIMER_CTRL_PERIODIC     (1 << 6)
27 #define TIMER_CTRL_ENABLE       (1 << 7)
28 
29 typedef struct {
30     ptimer_state *timer;
31     uint32_t control;
32     uint32_t limit;
33     int freq;
34     int int_level;
35     qemu_irq irq;
36 } arm_timer_state;
37 
38 /* Check all active timers, and schedule the next timer interrupt.  */
39 
40 static void arm_timer_update(arm_timer_state *s)
41 {
42     /* Update interrupts.  */
43     if (s->int_level && (s->control & TIMER_CTRL_IE)) {
44         qemu_irq_raise(s->irq);
45     } else {
46         qemu_irq_lower(s->irq);
47     }
48 }
49 
50 static uint32_t arm_timer_read(void *opaque, hwaddr offset)
51 {
52     arm_timer_state *s = (arm_timer_state *)opaque;
53 
54     switch (offset >> 2) {
55     case 0: /* TimerLoad */
56     case 6: /* TimerBGLoad */
57         return s->limit;
58     case 1: /* TimerValue */
59         return ptimer_get_count(s->timer);
60     case 2: /* TimerControl */
61         return s->control;
62     case 4: /* TimerRIS */
63         return s->int_level;
64     case 5: /* TimerMIS */
65         if ((s->control & TIMER_CTRL_IE) == 0)
66             return 0;
67         return s->int_level;
68     default:
69         qemu_log_mask(LOG_GUEST_ERROR,
70                       "%s: Bad offset %x\n", __func__, (int)offset);
71         return 0;
72     }
73 }
74 
75 /* Reset the timer limit after settings have changed.  */
76 static void arm_timer_recalibrate(arm_timer_state *s, int reload)
77 {
78     uint32_t limit;
79 
80     if ((s->control & (TIMER_CTRL_PERIODIC | TIMER_CTRL_ONESHOT)) == 0) {
81         /* Free running.  */
82         if (s->control & TIMER_CTRL_32BIT)
83             limit = 0xffffffff;
84         else
85             limit = 0xffff;
86     } else {
87           /* Periodic.  */
88           limit = s->limit;
89     }
90     ptimer_set_limit(s->timer, limit, reload);
91 }
92 
93 static void arm_timer_write(void *opaque, hwaddr offset,
94                             uint32_t value)
95 {
96     arm_timer_state *s = (arm_timer_state *)opaque;
97     int freq;
98 
99     switch (offset >> 2) {
100     case 0: /* TimerLoad */
101         s->limit = value;
102         arm_timer_recalibrate(s, 1);
103         break;
104     case 1: /* TimerValue */
105         /* ??? Linux seems to want to write to this readonly register.
106            Ignore it.  */
107         break;
108     case 2: /* TimerControl */
109         if (s->control & TIMER_CTRL_ENABLE) {
110             /* Pause the timer if it is running.  This may cause some
111                inaccuracy dure to rounding, but avoids a whole lot of other
112                messyness.  */
113             ptimer_stop(s->timer);
114         }
115         s->control = value;
116         freq = s->freq;
117         /* ??? Need to recalculate expiry time after changing divisor.  */
118         switch ((value >> 2) & 3) {
119         case 1: freq >>= 4; break;
120         case 2: freq >>= 8; break;
121         }
122         arm_timer_recalibrate(s, s->control & TIMER_CTRL_ENABLE);
123         ptimer_set_freq(s->timer, freq);
124         if (s->control & TIMER_CTRL_ENABLE) {
125             /* Restart the timer if still enabled.  */
126             ptimer_run(s->timer, (s->control & TIMER_CTRL_ONESHOT) != 0);
127         }
128         break;
129     case 3: /* TimerIntClr */
130         s->int_level = 0;
131         break;
132     case 6: /* TimerBGLoad */
133         s->limit = value;
134         arm_timer_recalibrate(s, 0);
135         break;
136     default:
137         qemu_log_mask(LOG_GUEST_ERROR,
138                       "%s: Bad offset %x\n", __func__, (int)offset);
139     }
140     arm_timer_update(s);
141 }
142 
143 static void arm_timer_tick(void *opaque)
144 {
145     arm_timer_state *s = (arm_timer_state *)opaque;
146     s->int_level = 1;
147     arm_timer_update(s);
148 }
149 
150 static const VMStateDescription vmstate_arm_timer = {
151     .name = "arm_timer",
152     .version_id = 1,
153     .minimum_version_id = 1,
154     .fields = (VMStateField[]) {
155         VMSTATE_UINT32(control, arm_timer_state),
156         VMSTATE_UINT32(limit, arm_timer_state),
157         VMSTATE_INT32(int_level, arm_timer_state),
158         VMSTATE_PTIMER(timer, arm_timer_state),
159         VMSTATE_END_OF_LIST()
160     }
161 };
162 
163 static arm_timer_state *arm_timer_init(uint32_t freq)
164 {
165     arm_timer_state *s;
166     QEMUBH *bh;
167 
168     s = (arm_timer_state *)g_malloc0(sizeof(arm_timer_state));
169     s->freq = freq;
170     s->control = TIMER_CTRL_IE;
171 
172     bh = qemu_bh_new(arm_timer_tick, s);
173     s->timer = ptimer_init(bh);
174     vmstate_register(NULL, -1, &vmstate_arm_timer, s);
175     return s;
176 }
177 
178 /* ARM PrimeCell SP804 dual timer module.
179  * Docs at
180  * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0271d/index.html
181 */
182 
183 #define TYPE_SP804 "sp804"
184 #define SP804(obj) OBJECT_CHECK(SP804State, (obj), TYPE_SP804)
185 
186 typedef struct SP804State {
187     SysBusDevice parent_obj;
188 
189     MemoryRegion iomem;
190     arm_timer_state *timer[2];
191     uint32_t freq0, freq1;
192     int level[2];
193     qemu_irq irq;
194 } SP804State;
195 
196 static const uint8_t sp804_ids[] = {
197     /* Timer ID */
198     0x04, 0x18, 0x14, 0,
199     /* PrimeCell ID */
200     0xd, 0xf0, 0x05, 0xb1
201 };
202 
203 /* Merge the IRQs from the two component devices.  */
204 static void sp804_set_irq(void *opaque, int irq, int level)
205 {
206     SP804State *s = (SP804State *)opaque;
207 
208     s->level[irq] = level;
209     qemu_set_irq(s->irq, s->level[0] || s->level[1]);
210 }
211 
212 static uint64_t sp804_read(void *opaque, hwaddr offset,
213                            unsigned size)
214 {
215     SP804State *s = (SP804State *)opaque;
216 
217     if (offset < 0x20) {
218         return arm_timer_read(s->timer[0], offset);
219     }
220     if (offset < 0x40) {
221         return arm_timer_read(s->timer[1], offset - 0x20);
222     }
223 
224     /* TimerPeriphID */
225     if (offset >= 0xfe0 && offset <= 0xffc) {
226         return sp804_ids[(offset - 0xfe0) >> 2];
227     }
228 
229     switch (offset) {
230     /* Integration Test control registers, which we won't support */
231     case 0xf00: /* TimerITCR */
232     case 0xf04: /* TimerITOP (strictly write only but..) */
233         qemu_log_mask(LOG_UNIMP,
234                       "%s: integration test registers unimplemented\n",
235                       __func__);
236         return 0;
237     }
238 
239     qemu_log_mask(LOG_GUEST_ERROR,
240                   "%s: Bad offset %x\n", __func__, (int)offset);
241     return 0;
242 }
243 
244 static void sp804_write(void *opaque, hwaddr offset,
245                         uint64_t value, unsigned size)
246 {
247     SP804State *s = (SP804State *)opaque;
248 
249     if (offset < 0x20) {
250         arm_timer_write(s->timer[0], offset, value);
251         return;
252     }
253 
254     if (offset < 0x40) {
255         arm_timer_write(s->timer[1], offset - 0x20, value);
256         return;
257     }
258 
259     /* Technically we could be writing to the Test Registers, but not likely */
260     qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %x\n",
261                   __func__, (int)offset);
262 }
263 
264 static const MemoryRegionOps sp804_ops = {
265     .read = sp804_read,
266     .write = sp804_write,
267     .endianness = DEVICE_NATIVE_ENDIAN,
268 };
269 
270 static const VMStateDescription vmstate_sp804 = {
271     .name = "sp804",
272     .version_id = 1,
273     .minimum_version_id = 1,
274     .fields = (VMStateField[]) {
275         VMSTATE_INT32_ARRAY(level, SP804State, 2),
276         VMSTATE_END_OF_LIST()
277     }
278 };
279 
280 static int sp804_init(SysBusDevice *sbd)
281 {
282     DeviceState *dev = DEVICE(sbd);
283     SP804State *s = SP804(dev);
284 
285     sysbus_init_irq(sbd, &s->irq);
286     s->timer[0] = arm_timer_init(s->freq0);
287     s->timer[1] = arm_timer_init(s->freq1);
288     s->timer[0]->irq = qemu_allocate_irq(sp804_set_irq, s, 0);
289     s->timer[1]->irq = qemu_allocate_irq(sp804_set_irq, s, 1);
290     memory_region_init_io(&s->iomem, OBJECT(s), &sp804_ops, s,
291                           "sp804", 0x1000);
292     sysbus_init_mmio(sbd, &s->iomem);
293     vmstate_register(dev, -1, &vmstate_sp804, s);
294     return 0;
295 }
296 
297 /* Integrator/CP timer module.  */
298 
299 #define TYPE_INTEGRATOR_PIT "integrator_pit"
300 #define INTEGRATOR_PIT(obj) \
301     OBJECT_CHECK(icp_pit_state, (obj), TYPE_INTEGRATOR_PIT)
302 
303 typedef struct {
304     SysBusDevice parent_obj;
305 
306     MemoryRegion iomem;
307     arm_timer_state *timer[3];
308 } icp_pit_state;
309 
310 static uint64_t icp_pit_read(void *opaque, hwaddr offset,
311                              unsigned size)
312 {
313     icp_pit_state *s = (icp_pit_state *)opaque;
314     int n;
315 
316     /* ??? Don't know the PrimeCell ID for this device.  */
317     n = offset >> 8;
318     if (n > 2) {
319         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
320         return 0;
321     }
322 
323     return arm_timer_read(s->timer[n], offset & 0xff);
324 }
325 
326 static void icp_pit_write(void *opaque, hwaddr offset,
327                           uint64_t value, unsigned size)
328 {
329     icp_pit_state *s = (icp_pit_state *)opaque;
330     int n;
331 
332     n = offset >> 8;
333     if (n > 2) {
334         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
335         return;
336     }
337 
338     arm_timer_write(s->timer[n], offset & 0xff, value);
339 }
340 
341 static const MemoryRegionOps icp_pit_ops = {
342     .read = icp_pit_read,
343     .write = icp_pit_write,
344     .endianness = DEVICE_NATIVE_ENDIAN,
345 };
346 
347 static int icp_pit_init(SysBusDevice *dev)
348 {
349     icp_pit_state *s = INTEGRATOR_PIT(dev);
350 
351     /* Timer 0 runs at the system clock speed (40MHz).  */
352     s->timer[0] = arm_timer_init(40000000);
353     /* The other two timers run at 1MHz.  */
354     s->timer[1] = arm_timer_init(1000000);
355     s->timer[2] = arm_timer_init(1000000);
356 
357     sysbus_init_irq(dev, &s->timer[0]->irq);
358     sysbus_init_irq(dev, &s->timer[1]->irq);
359     sysbus_init_irq(dev, &s->timer[2]->irq);
360 
361     memory_region_init_io(&s->iomem, OBJECT(s), &icp_pit_ops, s,
362                           "icp_pit", 0x1000);
363     sysbus_init_mmio(dev, &s->iomem);
364     /* This device has no state to save/restore.  The component timers will
365        save themselves.  */
366     return 0;
367 }
368 
369 static void icp_pit_class_init(ObjectClass *klass, void *data)
370 {
371     SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);
372 
373     sdc->init = icp_pit_init;
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     .class_init    = icp_pit_class_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     SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);
392     DeviceClass *k = DEVICE_CLASS(klass);
393 
394     sdc->init = sp804_init;
395     k->props = sp804_properties;
396 }
397 
398 static const TypeInfo sp804_info = {
399     .name          = TYPE_SP804,
400     .parent        = TYPE_SYS_BUS_DEVICE,
401     .instance_size = sizeof(SP804State),
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