xref: /openbmc/qemu/hw/timer/arm_timer.c (revision 40daca54)
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 "hw/sysbus.h"
11 #include "qemu/timer.h"
12 #include "qemu-common.h"
13 #include "hw/qdev.h"
14 #include "hw/ptimer.h"
15 #include "qemu/main-loop.h"
16 
17 /* Common timer implementation.  */
18 
19 #define TIMER_CTRL_ONESHOT      (1 << 0)
20 #define TIMER_CTRL_32BIT        (1 << 1)
21 #define TIMER_CTRL_DIV1         (0 << 2)
22 #define TIMER_CTRL_DIV16        (1 << 2)
23 #define TIMER_CTRL_DIV256       (2 << 2)
24 #define TIMER_CTRL_IE           (1 << 5)
25 #define TIMER_CTRL_PERIODIC     (1 << 6)
26 #define TIMER_CTRL_ENABLE       (1 << 7)
27 
28 typedef struct {
29     ptimer_state *timer;
30     uint32_t control;
31     uint32_t limit;
32     int freq;
33     int int_level;
34     qemu_irq irq;
35 } arm_timer_state;
36 
37 /* Check all active timers, and schedule the next timer interrupt.  */
38 
39 static void arm_timer_update(arm_timer_state *s)
40 {
41     /* Update interrupts.  */
42     if (s->int_level && (s->control & TIMER_CTRL_IE)) {
43         qemu_irq_raise(s->irq);
44     } else {
45         qemu_irq_lower(s->irq);
46     }
47 }
48 
49 static uint32_t arm_timer_read(void *opaque, hwaddr offset)
50 {
51     arm_timer_state *s = (arm_timer_state *)opaque;
52 
53     switch (offset >> 2) {
54     case 0: /* TimerLoad */
55     case 6: /* TimerBGLoad */
56         return s->limit;
57     case 1: /* TimerValue */
58         return ptimer_get_count(s->timer);
59     case 2: /* TimerControl */
60         return s->control;
61     case 4: /* TimerRIS */
62         return s->int_level;
63     case 5: /* TimerMIS */
64         if ((s->control & TIMER_CTRL_IE) == 0)
65             return 0;
66         return s->int_level;
67     default:
68         qemu_log_mask(LOG_GUEST_ERROR,
69                       "%s: Bad offset %x\n", __func__, (int)offset);
70         return 0;
71     }
72 }
73 
74 /* Reset the timer limit after settings have changed.  */
75 static void arm_timer_recalibrate(arm_timer_state *s, int reload)
76 {
77     uint32_t limit;
78 
79     if ((s->control & (TIMER_CTRL_PERIODIC | TIMER_CTRL_ONESHOT)) == 0) {
80         /* Free running.  */
81         if (s->control & TIMER_CTRL_32BIT)
82             limit = 0xffffffff;
83         else
84             limit = 0xffff;
85     } else {
86           /* Periodic.  */
87           limit = s->limit;
88     }
89     ptimer_set_limit(s->timer, limit, reload);
90 }
91 
92 static void arm_timer_write(void *opaque, hwaddr offset,
93                             uint32_t value)
94 {
95     arm_timer_state *s = (arm_timer_state *)opaque;
96     int freq;
97 
98     switch (offset >> 2) {
99     case 0: /* TimerLoad */
100         s->limit = value;
101         arm_timer_recalibrate(s, 1);
102         break;
103     case 1: /* TimerValue */
104         /* ??? Linux seems to want to write to this readonly register.
105            Ignore it.  */
106         break;
107     case 2: /* TimerControl */
108         if (s->control & TIMER_CTRL_ENABLE) {
109             /* Pause the timer if it is running.  This may cause some
110                inaccuracy dure to rounding, but avoids a whole lot of other
111                messyness.  */
112             ptimer_stop(s->timer);
113         }
114         s->control = value;
115         freq = s->freq;
116         /* ??? Need to recalculate expiry time after changing divisor.  */
117         switch ((value >> 2) & 3) {
118         case 1: freq >>= 4; break;
119         case 2: freq >>= 8; break;
120         }
121         arm_timer_recalibrate(s, s->control & TIMER_CTRL_ENABLE);
122         ptimer_set_freq(s->timer, freq);
123         if (s->control & TIMER_CTRL_ENABLE) {
124             /* Restart the timer if still enabled.  */
125             ptimer_run(s->timer, (s->control & TIMER_CTRL_ONESHOT) != 0);
126         }
127         break;
128     case 3: /* TimerIntClr */
129         s->int_level = 0;
130         break;
131     case 6: /* TimerBGLoad */
132         s->limit = value;
133         arm_timer_recalibrate(s, 0);
134         break;
135     default:
136         qemu_log_mask(LOG_GUEST_ERROR,
137                       "%s: Bad offset %x\n", __func__, (int)offset);
138     }
139     arm_timer_update(s);
140 }
141 
142 static void arm_timer_tick(void *opaque)
143 {
144     arm_timer_state *s = (arm_timer_state *)opaque;
145     s->int_level = 1;
146     arm_timer_update(s);
147 }
148 
149 static const VMStateDescription vmstate_arm_timer = {
150     .name = "arm_timer",
151     .version_id = 1,
152     .minimum_version_id = 1,
153     .minimum_version_id_old = 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     .minimum_version_id_old = 1,
275     .fields      = (VMStateField[]) {
276         VMSTATE_INT32_ARRAY(level, SP804State, 2),
277         VMSTATE_END_OF_LIST()
278     }
279 };
280 
281 static int sp804_init(SysBusDevice *sbd)
282 {
283     DeviceState *dev = DEVICE(sbd);
284     SP804State *s = SP804(dev);
285     qemu_irq *qi;
286 
287     qi = qemu_allocate_irqs(sp804_set_irq, s, 2);
288     sysbus_init_irq(sbd, &s->irq);
289     s->timer[0] = arm_timer_init(s->freq0);
290     s->timer[1] = arm_timer_init(s->freq1);
291     s->timer[0]->irq = qi[0];
292     s->timer[1]->irq = qi[1];
293     memory_region_init_io(&s->iomem, OBJECT(s), &sp804_ops, s,
294                           "sp804", 0x1000);
295     sysbus_init_mmio(sbd, &s->iomem);
296     vmstate_register(dev, -1, &vmstate_sp804, s);
297     return 0;
298 }
299 
300 /* Integrator/CP timer module.  */
301 
302 #define TYPE_INTEGRATOR_PIT "integrator_pit"
303 #define INTEGRATOR_PIT(obj) \
304     OBJECT_CHECK(icp_pit_state, (obj), TYPE_INTEGRATOR_PIT)
305 
306 typedef struct {
307     SysBusDevice parent_obj;
308 
309     MemoryRegion iomem;
310     arm_timer_state *timer[3];
311 } icp_pit_state;
312 
313 static uint64_t icp_pit_read(void *opaque, hwaddr offset,
314                              unsigned size)
315 {
316     icp_pit_state *s = (icp_pit_state *)opaque;
317     int n;
318 
319     /* ??? Don't know the PrimeCell ID for this device.  */
320     n = offset >> 8;
321     if (n > 2) {
322         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
323     }
324 
325     return arm_timer_read(s->timer[n], offset & 0xff);
326 }
327 
328 static void icp_pit_write(void *opaque, hwaddr offset,
329                           uint64_t value, unsigned size)
330 {
331     icp_pit_state *s = (icp_pit_state *)opaque;
332     int n;
333 
334     n = offset >> 8;
335     if (n > 2) {
336         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
337     }
338 
339     arm_timer_write(s->timer[n], offset & 0xff, value);
340 }
341 
342 static const MemoryRegionOps icp_pit_ops = {
343     .read = icp_pit_read,
344     .write = icp_pit_write,
345     .endianness = DEVICE_NATIVE_ENDIAN,
346 };
347 
348 static int icp_pit_init(SysBusDevice *dev)
349 {
350     icp_pit_state *s = INTEGRATOR_PIT(dev);
351 
352     /* Timer 0 runs at the system clock speed (40MHz).  */
353     s->timer[0] = arm_timer_init(40000000);
354     /* The other two timers run at 1MHz.  */
355     s->timer[1] = arm_timer_init(1000000);
356     s->timer[2] = arm_timer_init(1000000);
357 
358     sysbus_init_irq(dev, &s->timer[0]->irq);
359     sysbus_init_irq(dev, &s->timer[1]->irq);
360     sysbus_init_irq(dev, &s->timer[2]->irq);
361 
362     memory_region_init_io(&s->iomem, OBJECT(s), &icp_pit_ops, s,
363                           "icp_pit", 0x1000);
364     sysbus_init_mmio(dev, &s->iomem);
365     /* This device has no state to save/restore.  The component timers will
366        save themselves.  */
367     return 0;
368 }
369 
370 static void icp_pit_class_init(ObjectClass *klass, void *data)
371 {
372     SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);
373 
374     sdc->init = icp_pit_init;
375 }
376 
377 static const TypeInfo icp_pit_info = {
378     .name          = TYPE_INTEGRATOR_PIT,
379     .parent        = TYPE_SYS_BUS_DEVICE,
380     .instance_size = sizeof(icp_pit_state),
381     .class_init    = icp_pit_class_init,
382 };
383 
384 static Property sp804_properties[] = {
385     DEFINE_PROP_UINT32("freq0", SP804State, freq0, 1000000),
386     DEFINE_PROP_UINT32("freq1", SP804State, freq1, 1000000),
387     DEFINE_PROP_END_OF_LIST(),
388 };
389 
390 static void sp804_class_init(ObjectClass *klass, void *data)
391 {
392     SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);
393     DeviceClass *k = DEVICE_CLASS(klass);
394 
395     sdc->init = sp804_init;
396     k->props = sp804_properties;
397 }
398 
399 static const TypeInfo sp804_info = {
400     .name          = TYPE_SP804,
401     .parent        = TYPE_SYS_BUS_DEVICE,
402     .instance_size = sizeof(SP804State),
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