xref: /openbmc/qemu/hw/timer/slavio_timer.c (revision 64552b6b)
1 /*
2  * QEMU Sparc SLAVIO timer controller emulation
3  *
4  * Copyright (c) 2003-2005 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 
25 #include "qemu/osdep.h"
26 #include "qemu/timer.h"
27 #include "hw/irq.h"
28 #include "hw/ptimer.h"
29 #include "hw/sysbus.h"
30 #include "trace.h"
31 #include "qemu/main-loop.h"
32 #include "qemu/module.h"
33 
34 /*
35  * Registers of hardware timer in sun4m.
36  *
37  * This is the timer/counter part of chip STP2001 (Slave I/O), also
38  * produced as NCR89C105. See
39  * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR89C105.txt
40  *
41  * The 31-bit counter is incremented every 500ns by bit 9. Bits 8..0
42  * are zero. Bit 31 is 1 when count has been reached.
43  *
44  * Per-CPU timers interrupt local CPU, system timer uses normal
45  * interrupt routing.
46  *
47  */
48 
49 #define MAX_CPUS 16
50 
51 typedef struct CPUTimerState {
52     qemu_irq irq;
53     ptimer_state *timer;
54     uint32_t count, counthigh, reached;
55     /* processor only */
56     uint32_t run;
57     uint64_t limit;
58 } CPUTimerState;
59 
60 #define TYPE_SLAVIO_TIMER "slavio_timer"
61 #define SLAVIO_TIMER(obj) \
62     OBJECT_CHECK(SLAVIO_TIMERState, (obj), TYPE_SLAVIO_TIMER)
63 
64 typedef struct SLAVIO_TIMERState {
65     SysBusDevice parent_obj;
66 
67     uint32_t num_cpus;
68     uint32_t cputimer_mode;
69     CPUTimerState cputimer[MAX_CPUS + 1];
70 } SLAVIO_TIMERState;
71 
72 typedef struct TimerContext {
73     MemoryRegion iomem;
74     SLAVIO_TIMERState *s;
75     unsigned int timer_index; /* 0 for system, 1 ... MAX_CPUS for CPU timers */
76 } TimerContext;
77 
78 #define SYS_TIMER_SIZE 0x14
79 #define CPU_TIMER_SIZE 0x10
80 
81 #define TIMER_LIMIT         0
82 #define TIMER_COUNTER       1
83 #define TIMER_COUNTER_NORST 2
84 #define TIMER_STATUS        3
85 #define TIMER_MODE          4
86 
87 #define TIMER_COUNT_MASK32 0xfffffe00
88 #define TIMER_LIMIT_MASK32 0x7fffffff
89 #define TIMER_MAX_COUNT64  0x7ffffffffffffe00ULL
90 #define TIMER_MAX_COUNT32  0x7ffffe00ULL
91 #define TIMER_REACHED      0x80000000
92 #define TIMER_PERIOD       500ULL // 500ns
93 #define LIMIT_TO_PERIODS(l) (((l) >> 9) - 1)
94 #define PERIODS_TO_LIMIT(l) (((l) + 1) << 9)
95 
96 static int slavio_timer_is_user(TimerContext *tc)
97 {
98     SLAVIO_TIMERState *s = tc->s;
99     unsigned int timer_index = tc->timer_index;
100 
101     return timer_index != 0 && (s->cputimer_mode & (1 << (timer_index - 1)));
102 }
103 
104 // Update count, set irq, update expire_time
105 // Convert from ptimer countdown units
106 static void slavio_timer_get_out(CPUTimerState *t)
107 {
108     uint64_t count, limit;
109 
110     if (t->limit == 0) { /* free-run system or processor counter */
111         limit = TIMER_MAX_COUNT32;
112     } else {
113         limit = t->limit;
114     }
115     count = limit - PERIODS_TO_LIMIT(ptimer_get_count(t->timer));
116 
117     trace_slavio_timer_get_out(t->limit, t->counthigh, t->count);
118     t->count = count & TIMER_COUNT_MASK32;
119     t->counthigh = count >> 32;
120 }
121 
122 // timer callback
123 static void slavio_timer_irq(void *opaque)
124 {
125     TimerContext *tc = opaque;
126     SLAVIO_TIMERState *s = tc->s;
127     CPUTimerState *t = &s->cputimer[tc->timer_index];
128 
129     slavio_timer_get_out(t);
130     trace_slavio_timer_irq(t->counthigh, t->count);
131     /* if limit is 0 (free-run), there will be no match */
132     if (t->limit != 0) {
133         t->reached = TIMER_REACHED;
134     }
135     /* there is no interrupt if user timer or free-run */
136     if (!slavio_timer_is_user(tc) && t->limit != 0) {
137         qemu_irq_raise(t->irq);
138     }
139 }
140 
141 static uint64_t slavio_timer_mem_readl(void *opaque, hwaddr addr,
142                                        unsigned size)
143 {
144     TimerContext *tc = opaque;
145     SLAVIO_TIMERState *s = tc->s;
146     uint32_t saddr, ret;
147     unsigned int timer_index = tc->timer_index;
148     CPUTimerState *t = &s->cputimer[timer_index];
149 
150     saddr = addr >> 2;
151     switch (saddr) {
152     case TIMER_LIMIT:
153         // read limit (system counter mode) or read most signifying
154         // part of counter (user mode)
155         if (slavio_timer_is_user(tc)) {
156             // read user timer MSW
157             slavio_timer_get_out(t);
158             ret = t->counthigh | t->reached;
159         } else {
160             // read limit
161             // clear irq
162             qemu_irq_lower(t->irq);
163             t->reached = 0;
164             ret = t->limit & TIMER_LIMIT_MASK32;
165         }
166         break;
167     case TIMER_COUNTER:
168         // read counter and reached bit (system mode) or read lsbits
169         // of counter (user mode)
170         slavio_timer_get_out(t);
171         if (slavio_timer_is_user(tc)) { // read user timer LSW
172             ret = t->count & TIMER_MAX_COUNT64;
173         } else { // read limit
174             ret = (t->count & TIMER_MAX_COUNT32) |
175                 t->reached;
176         }
177         break;
178     case TIMER_STATUS:
179         // only available in processor counter/timer
180         // read start/stop status
181         if (timer_index > 0) {
182             ret = t->run;
183         } else {
184             ret = 0;
185         }
186         break;
187     case TIMER_MODE:
188         // only available in system counter
189         // read user/system mode
190         ret = s->cputimer_mode;
191         break;
192     default:
193         trace_slavio_timer_mem_readl_invalid(addr);
194         ret = 0;
195         break;
196     }
197     trace_slavio_timer_mem_readl(addr, ret);
198     return ret;
199 }
200 
201 static void slavio_timer_mem_writel(void *opaque, hwaddr addr,
202                                     uint64_t val, unsigned size)
203 {
204     TimerContext *tc = opaque;
205     SLAVIO_TIMERState *s = tc->s;
206     uint32_t saddr;
207     unsigned int timer_index = tc->timer_index;
208     CPUTimerState *t = &s->cputimer[timer_index];
209 
210     trace_slavio_timer_mem_writel(addr, val);
211     saddr = addr >> 2;
212     switch (saddr) {
213     case TIMER_LIMIT:
214         if (slavio_timer_is_user(tc)) {
215             uint64_t count;
216 
217             // set user counter MSW, reset counter
218             t->limit = TIMER_MAX_COUNT64;
219             t->counthigh = val & (TIMER_MAX_COUNT64 >> 32);
220             t->reached = 0;
221             count = ((uint64_t)t->counthigh << 32) | t->count;
222             trace_slavio_timer_mem_writel_limit(timer_index, count);
223             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
224         } else {
225             // set limit, reset counter
226             qemu_irq_lower(t->irq);
227             t->limit = val & TIMER_MAX_COUNT32;
228             if (t->timer) {
229                 if (t->limit == 0) { /* free-run */
230                     ptimer_set_limit(t->timer,
231                                      LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
232                 } else {
233                     ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 1);
234                 }
235             }
236         }
237         break;
238     case TIMER_COUNTER:
239         if (slavio_timer_is_user(tc)) {
240             uint64_t count;
241 
242             // set user counter LSW, reset counter
243             t->limit = TIMER_MAX_COUNT64;
244             t->count = val & TIMER_MAX_COUNT64;
245             t->reached = 0;
246             count = ((uint64_t)t->counthigh) << 32 | t->count;
247             trace_slavio_timer_mem_writel_limit(timer_index, count);
248             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
249         } else {
250             trace_slavio_timer_mem_writel_counter_invalid();
251         }
252         break;
253     case TIMER_COUNTER_NORST:
254         // set limit without resetting counter
255         t->limit = val & TIMER_MAX_COUNT32;
256         if (t->limit == 0) { /* free-run */
257             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 0);
258         } else {
259             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 0);
260         }
261         break;
262     case TIMER_STATUS:
263         if (slavio_timer_is_user(tc)) {
264             // start/stop user counter
265             if (val & 1) {
266                 trace_slavio_timer_mem_writel_status_start(timer_index);
267                 ptimer_run(t->timer, 0);
268             } else {
269                 trace_slavio_timer_mem_writel_status_stop(timer_index);
270                 ptimer_stop(t->timer);
271             }
272         }
273         t->run = val & 1;
274         break;
275     case TIMER_MODE:
276         if (timer_index == 0) {
277             unsigned int i;
278 
279             for (i = 0; i < s->num_cpus; i++) {
280                 unsigned int processor = 1 << i;
281                 CPUTimerState *curr_timer = &s->cputimer[i + 1];
282 
283                 // check for a change in timer mode for this processor
284                 if ((val & processor) != (s->cputimer_mode & processor)) {
285                     if (val & processor) { // counter -> user timer
286                         qemu_irq_lower(curr_timer->irq);
287                         // counters are always running
288                         if (!curr_timer->run) {
289                             ptimer_stop(curr_timer->timer);
290                         }
291                         // user timer limit is always the same
292                         curr_timer->limit = TIMER_MAX_COUNT64;
293                         ptimer_set_limit(curr_timer->timer,
294                                          LIMIT_TO_PERIODS(curr_timer->limit),
295                                          1);
296                         // set this processors user timer bit in config
297                         // register
298                         s->cputimer_mode |= processor;
299                         trace_slavio_timer_mem_writel_mode_user(timer_index);
300                     } else { // user timer -> counter
301                         // start the counter
302                         ptimer_run(curr_timer->timer, 0);
303                         // clear this processors user timer bit in config
304                         // register
305                         s->cputimer_mode &= ~processor;
306                         trace_slavio_timer_mem_writel_mode_counter(timer_index);
307                     }
308                 }
309             }
310         } else {
311             trace_slavio_timer_mem_writel_mode_invalid();
312         }
313         break;
314     default:
315         trace_slavio_timer_mem_writel_invalid(addr);
316         break;
317     }
318 }
319 
320 static const MemoryRegionOps slavio_timer_mem_ops = {
321     .read = slavio_timer_mem_readl,
322     .write = slavio_timer_mem_writel,
323     .endianness = DEVICE_NATIVE_ENDIAN,
324     .valid = {
325         .min_access_size = 4,
326         .max_access_size = 4,
327     },
328 };
329 
330 static const VMStateDescription vmstate_timer = {
331     .name ="timer",
332     .version_id = 3,
333     .minimum_version_id = 3,
334     .fields = (VMStateField[]) {
335         VMSTATE_UINT64(limit, CPUTimerState),
336         VMSTATE_UINT32(count, CPUTimerState),
337         VMSTATE_UINT32(counthigh, CPUTimerState),
338         VMSTATE_UINT32(reached, CPUTimerState),
339         VMSTATE_UINT32(run    , CPUTimerState),
340         VMSTATE_PTIMER(timer, CPUTimerState),
341         VMSTATE_END_OF_LIST()
342     }
343 };
344 
345 static const VMStateDescription vmstate_slavio_timer = {
346     .name ="slavio_timer",
347     .version_id = 3,
348     .minimum_version_id = 3,
349     .fields = (VMStateField[]) {
350         VMSTATE_STRUCT_ARRAY(cputimer, SLAVIO_TIMERState, MAX_CPUS + 1, 3,
351                              vmstate_timer, CPUTimerState),
352         VMSTATE_END_OF_LIST()
353     }
354 };
355 
356 static void slavio_timer_reset(DeviceState *d)
357 {
358     SLAVIO_TIMERState *s = SLAVIO_TIMER(d);
359     unsigned int i;
360     CPUTimerState *curr_timer;
361 
362     for (i = 0; i <= MAX_CPUS; i++) {
363         curr_timer = &s->cputimer[i];
364         curr_timer->limit = 0;
365         curr_timer->count = 0;
366         curr_timer->reached = 0;
367         if (i <= s->num_cpus) {
368             ptimer_set_limit(curr_timer->timer,
369                              LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
370             ptimer_run(curr_timer->timer, 0);
371             curr_timer->run = 1;
372         }
373     }
374     s->cputimer_mode = 0;
375 }
376 
377 static void slavio_timer_init(Object *obj)
378 {
379     SLAVIO_TIMERState *s = SLAVIO_TIMER(obj);
380     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
381     QEMUBH *bh;
382     unsigned int i;
383     TimerContext *tc;
384 
385     for (i = 0; i <= MAX_CPUS; i++) {
386         uint64_t size;
387         char timer_name[20];
388 
389         tc = g_malloc0(sizeof(TimerContext));
390         tc->s = s;
391         tc->timer_index = i;
392 
393         bh = qemu_bh_new(slavio_timer_irq, tc);
394         s->cputimer[i].timer = ptimer_init(bh, PTIMER_POLICY_DEFAULT);
395         ptimer_set_period(s->cputimer[i].timer, TIMER_PERIOD);
396 
397         size = i == 0 ? SYS_TIMER_SIZE : CPU_TIMER_SIZE;
398         snprintf(timer_name, sizeof(timer_name), "timer-%i", i);
399         memory_region_init_io(&tc->iomem, obj, &slavio_timer_mem_ops, tc,
400                               timer_name, size);
401         sysbus_init_mmio(dev, &tc->iomem);
402 
403         sysbus_init_irq(dev, &s->cputimer[i].irq);
404     }
405 }
406 
407 static Property slavio_timer_properties[] = {
408     DEFINE_PROP_UINT32("num_cpus",  SLAVIO_TIMERState, num_cpus,  0),
409     DEFINE_PROP_END_OF_LIST(),
410 };
411 
412 static void slavio_timer_class_init(ObjectClass *klass, void *data)
413 {
414     DeviceClass *dc = DEVICE_CLASS(klass);
415 
416     dc->reset = slavio_timer_reset;
417     dc->vmsd = &vmstate_slavio_timer;
418     dc->props = slavio_timer_properties;
419 }
420 
421 static const TypeInfo slavio_timer_info = {
422     .name          = TYPE_SLAVIO_TIMER,
423     .parent        = TYPE_SYS_BUS_DEVICE,
424     .instance_size = sizeof(SLAVIO_TIMERState),
425     .instance_init = slavio_timer_init,
426     .class_init    = slavio_timer_class_init,
427 };
428 
429 static void slavio_timer_register_types(void)
430 {
431     type_register_static(&slavio_timer_info);
432 }
433 
434 type_init(slavio_timer_register_types)
435