xref: /openbmc/qemu/hw/timer/a9gtimer.c (revision 7d87775f)
1 /*
2  * Global peripheral timer block for ARM A9MP
3  *
4  * (C) 2013 Xilinx Inc.
5  *
6  * Written by François LEGAL
7  * Written by Peter Crosthwaite <peter.crosthwaite@xilinx.com>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * as published by the Free Software Foundation; either version
12  * 2 of the License, or (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License along
20  * with this program; if not, see <http://www.gnu.org/licenses/>.
21  */
22 
23 #include "qemu/osdep.h"
24 #include "hw/hw.h"
25 #include "hw/irq.h"
26 #include "hw/qdev-properties.h"
27 #include "hw/timer/a9gtimer.h"
28 #include "migration/vmstate.h"
29 #include "qapi/error.h"
30 #include "qemu/timer.h"
31 #include "qemu/bitops.h"
32 #include "qemu/log.h"
33 #include "qemu/module.h"
34 #include "hw/core/cpu.h"
35 #include "sysemu/qtest.h"
36 
37 #ifndef A9_GTIMER_ERR_DEBUG
38 #define A9_GTIMER_ERR_DEBUG 0
39 #endif
40 
41 #define DB_PRINT_L(level, ...) do { \
42     if (A9_GTIMER_ERR_DEBUG > (level)) { \
43         fprintf(stderr,  ": %s: ", __func__); \
44         fprintf(stderr, ## __VA_ARGS__); \
45     } \
46 } while (0)
47 
48 #define DB_PRINT(...) DB_PRINT_L(0, ## __VA_ARGS__)
49 
50 static inline int a9_gtimer_get_current_cpu(A9GTimerState *s)
51 {
52     if (qtest_enabled()) {
53         return 0;
54     }
55 
56     if (current_cpu->cpu_index >= s->num_cpu) {
57         hw_error("a9gtimer: num-cpu %d but this cpu is %d!\n",
58                  s->num_cpu, current_cpu->cpu_index);
59     }
60     return current_cpu->cpu_index;
61 }
62 
63 static inline uint64_t a9_gtimer_get_conv(A9GTimerState *s)
64 {
65     uint64_t prescale = extract32(s->control, R_CONTROL_PRESCALER_SHIFT,
66                                   R_CONTROL_PRESCALER_LEN);
67 
68     return (prescale + 1) * 10;
69 }
70 
71 static A9GTimerUpdate a9_gtimer_get_update(A9GTimerState *s)
72 {
73     A9GTimerUpdate ret;
74 
75     ret.now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
76     ret.new = s->ref_counter +
77               (ret.now - s->cpu_ref_time) / a9_gtimer_get_conv(s);
78     return ret;
79 }
80 
81 static void a9_gtimer_update(A9GTimerState *s, bool sync)
82 {
83 
84     A9GTimerUpdate update = a9_gtimer_get_update(s);
85     int i;
86     int64_t next_cdiff = 0;
87 
88     for (i = 0; i < s->num_cpu; ++i) {
89         A9GTimerPerCPU *gtb = &s->per_cpu[i];
90         int64_t cdiff = 0;
91 
92         if ((s->control & R_CONTROL_TIMER_ENABLE) &&
93                 (gtb->control & R_CONTROL_COMP_ENABLE)) {
94             /* R2p0+, where the compare function is >= */
95             if (gtb->compare < update.new) {
96                 DB_PRINT("Compare event happened for CPU %d\n", i);
97                 gtb->status = 1;
98                 if (gtb->control & R_CONTROL_AUTO_INCREMENT && gtb->inc) {
99                     uint64_t inc =
100                         QEMU_ALIGN_UP(update.new - gtb->compare, gtb->inc);
101                     DB_PRINT("Auto incrementing timer compare by %"
102                                                         PRId64 "\n", inc);
103                     gtb->compare += inc;
104                 }
105             }
106             cdiff = (int64_t)gtb->compare - (int64_t)update.new + 1;
107             if (cdiff > 0 && (cdiff < next_cdiff || !next_cdiff)) {
108                 next_cdiff = cdiff;
109             }
110         }
111 
112         qemu_set_irq(gtb->irq,
113                      gtb->status && (gtb->control & R_CONTROL_IRQ_ENABLE));
114     }
115 
116     timer_del(s->timer);
117     if (next_cdiff) {
118         DB_PRINT("scheduling qemu_timer to fire again in %"
119                  PRIx64 " cycles\n", next_cdiff);
120         timer_mod(s->timer, update.now + next_cdiff * a9_gtimer_get_conv(s));
121     }
122 
123     if (s->control & R_CONTROL_TIMER_ENABLE) {
124         s->counter = update.new;
125     }
126 
127     if (sync) {
128         s->cpu_ref_time = update.now;
129         s->ref_counter = s->counter;
130     }
131 }
132 
133 static void a9_gtimer_update_no_sync(void *opaque)
134 {
135     A9GTimerState *s = A9_GTIMER(opaque);
136 
137     a9_gtimer_update(s, false);
138 }
139 
140 static uint64_t a9_gtimer_read(void *opaque, hwaddr addr, unsigned size)
141 {
142     A9GTimerPerCPU *gtb = (A9GTimerPerCPU *)opaque;
143     A9GTimerState *s = gtb->parent;
144     A9GTimerUpdate update;
145     uint64_t ret = 0;
146     int shift = 0;
147 
148     switch (addr) {
149     case R_COUNTER_HI:
150         shift = 32;
151         /* fallthrough */
152     case R_COUNTER_LO:
153         update = a9_gtimer_get_update(s);
154         ret = extract64(update.new, shift, 32);
155         break;
156     case R_CONTROL:
157         ret = s->control | gtb->control;
158         break;
159     case R_INTERRUPT_STATUS:
160         ret = gtb->status;
161         break;
162     case R_COMPARATOR_HI:
163         shift = 32;
164         /* fallthrough */
165     case R_COMPARATOR_LO:
166         ret = extract64(gtb->compare, shift, 32);
167         break;
168     case R_AUTO_INCREMENT:
169         ret =  gtb->inc;
170         break;
171     default:
172         qemu_log_mask(LOG_GUEST_ERROR, "bad a9gtimer register: %x\n",
173                       (unsigned)addr);
174         return 0;
175     }
176 
177     DB_PRINT("addr:%#x data:%#08" PRIx64 "\n", (unsigned)addr, ret);
178     return ret;
179 }
180 
181 static void a9_gtimer_write(void *opaque, hwaddr addr, uint64_t value,
182                             unsigned size)
183 {
184     A9GTimerPerCPU *gtb = (A9GTimerPerCPU *)opaque;
185     A9GTimerState *s = gtb->parent;
186     int shift = 0;
187 
188     DB_PRINT("addr:%#x data:%#08" PRIx64 "\n", (unsigned)addr, value);
189 
190     switch (addr) {
191     case R_COUNTER_HI:
192         shift = 32;
193         /* fallthrough */
194     case R_COUNTER_LO:
195         /*
196          * Keep it simple - ARM docco explicitly says to disable timer before
197          * modding it, so don't bother trying to do all the difficult on the fly
198          * timer modifications - (if they even work in real hardware??).
199          */
200         if (s->control & R_CONTROL_TIMER_ENABLE) {
201             qemu_log_mask(LOG_GUEST_ERROR, "Cannot mod running ARM gtimer\n");
202             return;
203         }
204         s->counter = deposit64(s->counter, shift, 32, value);
205         return;
206     case R_CONTROL:
207         a9_gtimer_update(s, (value ^ s->control) & R_CONTROL_NEEDS_SYNC);
208         gtb->control = value & R_CONTROL_BANKED;
209         s->control = value & ~R_CONTROL_BANKED;
210         break;
211     case R_INTERRUPT_STATUS:
212         a9_gtimer_update(s, false);
213         gtb->status &= ~value;
214         break;
215     case R_COMPARATOR_HI:
216         shift = 32;
217         /* fallthrough */
218     case R_COMPARATOR_LO:
219         a9_gtimer_update(s, false);
220         gtb->compare = deposit64(gtb->compare, shift, 32, value);
221         break;
222     case R_AUTO_INCREMENT:
223         gtb->inc = value;
224         return;
225     default:
226         return;
227     }
228 
229     a9_gtimer_update(s, false);
230 }
231 
232 /* Wrapper functions to implement the "read global timer for
233  * the current CPU" memory regions.
234  */
235 static uint64_t a9_gtimer_this_read(void *opaque, hwaddr addr,
236                                     unsigned size)
237 {
238     A9GTimerState *s = A9_GTIMER(opaque);
239     int id = a9_gtimer_get_current_cpu(s);
240 
241     /* no \n so concatenates with message from read fn */
242     DB_PRINT("CPU:%d:", id);
243 
244     return a9_gtimer_read(&s->per_cpu[id], addr, size);
245 }
246 
247 static void a9_gtimer_this_write(void *opaque, hwaddr addr,
248                                  uint64_t value, unsigned size)
249 {
250     A9GTimerState *s = A9_GTIMER(opaque);
251     int id = a9_gtimer_get_current_cpu(s);
252 
253     /* no \n so concatenates with message from write fn */
254     DB_PRINT("CPU:%d:", id);
255 
256     a9_gtimer_write(&s->per_cpu[id], addr, value, size);
257 }
258 
259 static const MemoryRegionOps a9_gtimer_this_ops = {
260     .read = a9_gtimer_this_read,
261     .write = a9_gtimer_this_write,
262     .valid = {
263         .min_access_size = 4,
264         .max_access_size = 4,
265     },
266     .endianness = DEVICE_NATIVE_ENDIAN,
267 };
268 
269 static const MemoryRegionOps a9_gtimer_ops = {
270     .read = a9_gtimer_read,
271     .write = a9_gtimer_write,
272     .valid = {
273         .min_access_size = 4,
274         .max_access_size = 4,
275     },
276     .endianness = DEVICE_NATIVE_ENDIAN,
277 };
278 
279 static void a9_gtimer_reset(DeviceState *dev)
280 {
281     A9GTimerState *s = A9_GTIMER(dev);
282     int i;
283 
284     s->counter = 0;
285     s->control = 0;
286 
287     for (i = 0; i < s->num_cpu; i++) {
288         A9GTimerPerCPU *gtb = &s->per_cpu[i];
289 
290         gtb->control = 0;
291         gtb->status = 0;
292         gtb->compare = 0;
293         gtb->inc = 0;
294     }
295     a9_gtimer_update(s, false);
296 }
297 
298 static void a9_gtimer_realize(DeviceState *dev, Error **errp)
299 {
300     A9GTimerState *s = A9_GTIMER(dev);
301     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
302     int i;
303 
304     if (s->num_cpu < 1 || s->num_cpu > A9_GTIMER_MAX_CPUS) {
305         error_setg(errp, "%s: num-cpu must be between 1 and %d",
306                    __func__, A9_GTIMER_MAX_CPUS);
307         return;
308     }
309 
310     memory_region_init_io(&s->iomem, OBJECT(dev), &a9_gtimer_this_ops, s,
311                           "a9gtimer shared", 0x20);
312     sysbus_init_mmio(sbd, &s->iomem);
313     s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, a9_gtimer_update_no_sync, s);
314 
315     for (i = 0; i < s->num_cpu; i++) {
316         A9GTimerPerCPU *gtb = &s->per_cpu[i];
317 
318         gtb->parent = s;
319         sysbus_init_irq(sbd, &gtb->irq);
320         memory_region_init_io(&gtb->iomem, OBJECT(dev), &a9_gtimer_ops, gtb,
321                               "a9gtimer per cpu", 0x20);
322         sysbus_init_mmio(sbd, &gtb->iomem);
323     }
324 }
325 
326 static bool vmstate_a9_gtimer_control_needed(void *opaque)
327 {
328     A9GTimerState *s = opaque;
329     return s->control != 0;
330 }
331 
332 static const VMStateDescription vmstate_a9_gtimer_per_cpu = {
333     .name = "arm.cortex-a9-global-timer.percpu",
334     .version_id = 1,
335     .minimum_version_id = 1,
336     .fields = (const VMStateField[]) {
337         VMSTATE_UINT32(control, A9GTimerPerCPU),
338         VMSTATE_UINT64(compare, A9GTimerPerCPU),
339         VMSTATE_UINT32(status, A9GTimerPerCPU),
340         VMSTATE_UINT32(inc, A9GTimerPerCPU),
341         VMSTATE_END_OF_LIST()
342     }
343 };
344 
345 static const VMStateDescription vmstate_a9_gtimer_control = {
346     .name = "arm.cortex-a9-global-timer.control",
347     .version_id = 1,
348     .minimum_version_id = 1,
349     .needed = vmstate_a9_gtimer_control_needed,
350     .fields = (const VMStateField[]) {
351         VMSTATE_UINT32(control, A9GTimerState),
352         VMSTATE_END_OF_LIST()
353     }
354 };
355 
356 static const VMStateDescription vmstate_a9_gtimer = {
357     .name = "arm.cortex-a9-global-timer",
358     .version_id = 1,
359     .minimum_version_id = 1,
360     .fields = (const VMStateField[]) {
361         VMSTATE_TIMER_PTR(timer, A9GTimerState),
362         VMSTATE_UINT64(counter, A9GTimerState),
363         VMSTATE_UINT64(ref_counter, A9GTimerState),
364         VMSTATE_UINT64(cpu_ref_time, A9GTimerState),
365         VMSTATE_STRUCT_VARRAY_UINT32(per_cpu, A9GTimerState, num_cpu,
366                                      1, vmstate_a9_gtimer_per_cpu,
367                                      A9GTimerPerCPU),
368         VMSTATE_END_OF_LIST()
369     },
370     .subsections = (const VMStateDescription * const []) {
371         &vmstate_a9_gtimer_control,
372         NULL
373     }
374 };
375 
376 static Property a9_gtimer_properties[] = {
377     DEFINE_PROP_UINT32("num-cpu", A9GTimerState, num_cpu, 0),
378     DEFINE_PROP_END_OF_LIST()
379 };
380 
381 static void a9_gtimer_class_init(ObjectClass *klass, void *data)
382 {
383     DeviceClass *dc = DEVICE_CLASS(klass);
384 
385     dc->realize = a9_gtimer_realize;
386     dc->vmsd = &vmstate_a9_gtimer;
387     device_class_set_legacy_reset(dc, a9_gtimer_reset);
388     device_class_set_props(dc, a9_gtimer_properties);
389 }
390 
391 static const TypeInfo a9_gtimer_info = {
392     .name          = TYPE_A9_GTIMER,
393     .parent        = TYPE_SYS_BUS_DEVICE,
394     .instance_size = sizeof(A9GTimerState),
395     .class_init    = a9_gtimer_class_init,
396 };
397 
398 static void a9_gtimer_register_types(void)
399 {
400     type_register_static(&a9_gtimer_info);
401 }
402 
403 type_init(a9_gtimer_register_types)
404