xref: /openbmc/qemu/hw/timer/arm_timer.c (revision acb0ef58)
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     .fields = (VMStateField[]) {
154         VMSTATE_UINT32(control, arm_timer_state),
155         VMSTATE_UINT32(limit, arm_timer_state),
156         VMSTATE_INT32(int_level, arm_timer_state),
157         VMSTATE_PTIMER(timer, arm_timer_state),
158         VMSTATE_END_OF_LIST()
159     }
160 };
161 
162 static arm_timer_state *arm_timer_init(uint32_t freq)
163 {
164     arm_timer_state *s;
165     QEMUBH *bh;
166 
167     s = (arm_timer_state *)g_malloc0(sizeof(arm_timer_state));
168     s->freq = freq;
169     s->control = TIMER_CTRL_IE;
170 
171     bh = qemu_bh_new(arm_timer_tick, s);
172     s->timer = ptimer_init(bh);
173     vmstate_register(NULL, -1, &vmstate_arm_timer, s);
174     return s;
175 }
176 
177 /* ARM PrimeCell SP804 dual timer module.
178  * Docs at
179  * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0271d/index.html
180 */
181 
182 #define TYPE_SP804 "sp804"
183 #define SP804(obj) OBJECT_CHECK(SP804State, (obj), TYPE_SP804)
184 
185 typedef struct SP804State {
186     SysBusDevice parent_obj;
187 
188     MemoryRegion iomem;
189     arm_timer_state *timer[2];
190     uint32_t freq0, freq1;
191     int level[2];
192     qemu_irq irq;
193 } SP804State;
194 
195 static const uint8_t sp804_ids[] = {
196     /* Timer ID */
197     0x04, 0x18, 0x14, 0,
198     /* PrimeCell ID */
199     0xd, 0xf0, 0x05, 0xb1
200 };
201 
202 /* Merge the IRQs from the two component devices.  */
203 static void sp804_set_irq(void *opaque, int irq, int level)
204 {
205     SP804State *s = (SP804State *)opaque;
206 
207     s->level[irq] = level;
208     qemu_set_irq(s->irq, s->level[0] || s->level[1]);
209 }
210 
211 static uint64_t sp804_read(void *opaque, hwaddr offset,
212                            unsigned size)
213 {
214     SP804State *s = (SP804State *)opaque;
215 
216     if (offset < 0x20) {
217         return arm_timer_read(s->timer[0], offset);
218     }
219     if (offset < 0x40) {
220         return arm_timer_read(s->timer[1], offset - 0x20);
221     }
222 
223     /* TimerPeriphID */
224     if (offset >= 0xfe0 && offset <= 0xffc) {
225         return sp804_ids[(offset - 0xfe0) >> 2];
226     }
227 
228     switch (offset) {
229     /* Integration Test control registers, which we won't support */
230     case 0xf00: /* TimerITCR */
231     case 0xf04: /* TimerITOP (strictly write only but..) */
232         qemu_log_mask(LOG_UNIMP,
233                       "%s: integration test registers unimplemented\n",
234                       __func__);
235         return 0;
236     }
237 
238     qemu_log_mask(LOG_GUEST_ERROR,
239                   "%s: Bad offset %x\n", __func__, (int)offset);
240     return 0;
241 }
242 
243 static void sp804_write(void *opaque, hwaddr offset,
244                         uint64_t value, unsigned size)
245 {
246     SP804State *s = (SP804State *)opaque;
247 
248     if (offset < 0x20) {
249         arm_timer_write(s->timer[0], offset, value);
250         return;
251     }
252 
253     if (offset < 0x40) {
254         arm_timer_write(s->timer[1], offset - 0x20, value);
255         return;
256     }
257 
258     /* Technically we could be writing to the Test Registers, but not likely */
259     qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %x\n",
260                   __func__, (int)offset);
261 }
262 
263 static const MemoryRegionOps sp804_ops = {
264     .read = sp804_read,
265     .write = sp804_write,
266     .endianness = DEVICE_NATIVE_ENDIAN,
267 };
268 
269 static const VMStateDescription vmstate_sp804 = {
270     .name = "sp804",
271     .version_id = 1,
272     .minimum_version_id = 1,
273     .fields = (VMStateField[]) {
274         VMSTATE_INT32_ARRAY(level, SP804State, 2),
275         VMSTATE_END_OF_LIST()
276     }
277 };
278 
279 static int sp804_init(SysBusDevice *sbd)
280 {
281     DeviceState *dev = DEVICE(sbd);
282     SP804State *s = SP804(dev);
283     qemu_irq *qi;
284 
285     qi = qemu_allocate_irqs(sp804_set_irq, s, 2);
286     sysbus_init_irq(sbd, &s->irq);
287     s->timer[0] = arm_timer_init(s->freq0);
288     s->timer[1] = arm_timer_init(s->freq1);
289     s->timer[0]->irq = qi[0];
290     s->timer[1]->irq = qi[1];
291     memory_region_init_io(&s->iomem, OBJECT(s), &sp804_ops, s,
292                           "sp804", 0x1000);
293     sysbus_init_mmio(sbd, &s->iomem);
294     vmstate_register(dev, -1, &vmstate_sp804, s);
295     return 0;
296 }
297 
298 /* Integrator/CP timer module.  */
299 
300 #define TYPE_INTEGRATOR_PIT "integrator_pit"
301 #define INTEGRATOR_PIT(obj) \
302     OBJECT_CHECK(icp_pit_state, (obj), TYPE_INTEGRATOR_PIT)
303 
304 typedef struct {
305     SysBusDevice parent_obj;
306 
307     MemoryRegion iomem;
308     arm_timer_state *timer[3];
309 } icp_pit_state;
310 
311 static uint64_t icp_pit_read(void *opaque, hwaddr offset,
312                              unsigned size)
313 {
314     icp_pit_state *s = (icp_pit_state *)opaque;
315     int n;
316 
317     /* ??? Don't know the PrimeCell ID for this device.  */
318     n = offset >> 8;
319     if (n > 2) {
320         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
321         return 0;
322     }
323 
324     return arm_timer_read(s->timer[n], offset & 0xff);
325 }
326 
327 static void icp_pit_write(void *opaque, hwaddr offset,
328                           uint64_t value, unsigned size)
329 {
330     icp_pit_state *s = (icp_pit_state *)opaque;
331     int n;
332 
333     n = offset >> 8;
334     if (n > 2) {
335         qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad timer %d\n", __func__, n);
336         return;
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