xref: /openbmc/qemu/hw/timer/slavio_timer.c (revision 40d6ee94)
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/ptimer.h"
28 #include "hw/sysbus.h"
29 #include "trace.h"
30 #include "qemu/main-loop.h"
31 
32 /*
33  * Registers of hardware timer in sun4m.
34  *
35  * This is the timer/counter part of chip STP2001 (Slave I/O), also
36  * produced as NCR89C105. See
37  * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR89C105.txt
38  *
39  * The 31-bit counter is incremented every 500ns by bit 9. Bits 8..0
40  * are zero. Bit 31 is 1 when count has been reached.
41  *
42  * Per-CPU timers interrupt local CPU, system timer uses normal
43  * interrupt routing.
44  *
45  */
46 
47 #define MAX_CPUS 16
48 
49 typedef struct CPUTimerState {
50     qemu_irq irq;
51     ptimer_state *timer;
52     uint32_t count, counthigh, reached;
53     /* processor only */
54     uint32_t run;
55     uint64_t limit;
56 } CPUTimerState;
57 
58 #define TYPE_SLAVIO_TIMER "slavio_timer"
59 #define SLAVIO_TIMER(obj) \
60     OBJECT_CHECK(SLAVIO_TIMERState, (obj), TYPE_SLAVIO_TIMER)
61 
62 typedef struct SLAVIO_TIMERState {
63     SysBusDevice parent_obj;
64 
65     uint32_t num_cpus;
66     uint32_t cputimer_mode;
67     CPUTimerState cputimer[MAX_CPUS + 1];
68 } SLAVIO_TIMERState;
69 
70 typedef struct TimerContext {
71     MemoryRegion iomem;
72     SLAVIO_TIMERState *s;
73     unsigned int timer_index; /* 0 for system, 1 ... MAX_CPUS for CPU timers */
74 } TimerContext;
75 
76 #define SYS_TIMER_SIZE 0x14
77 #define CPU_TIMER_SIZE 0x10
78 
79 #define TIMER_LIMIT         0
80 #define TIMER_COUNTER       1
81 #define TIMER_COUNTER_NORST 2
82 #define TIMER_STATUS        3
83 #define TIMER_MODE          4
84 
85 #define TIMER_COUNT_MASK32 0xfffffe00
86 #define TIMER_LIMIT_MASK32 0x7fffffff
87 #define TIMER_MAX_COUNT64  0x7ffffffffffffe00ULL
88 #define TIMER_MAX_COUNT32  0x7ffffe00ULL
89 #define TIMER_REACHED      0x80000000
90 #define TIMER_PERIOD       500ULL // 500ns
91 #define LIMIT_TO_PERIODS(l) (((l) >> 9) - 1)
92 #define PERIODS_TO_LIMIT(l) (((l) + 1) << 9)
93 
94 static int slavio_timer_is_user(TimerContext *tc)
95 {
96     SLAVIO_TIMERState *s = tc->s;
97     unsigned int timer_index = tc->timer_index;
98 
99     return timer_index != 0 && (s->cputimer_mode & (1 << (timer_index - 1)));
100 }
101 
102 // Update count, set irq, update expire_time
103 // Convert from ptimer countdown units
104 static void slavio_timer_get_out(CPUTimerState *t)
105 {
106     uint64_t count, limit;
107 
108     if (t->limit == 0) { /* free-run system or processor counter */
109         limit = TIMER_MAX_COUNT32;
110     } else {
111         limit = t->limit;
112     }
113     count = limit - PERIODS_TO_LIMIT(ptimer_get_count(t->timer));
114 
115     trace_slavio_timer_get_out(t->limit, t->counthigh, t->count);
116     t->count = count & TIMER_COUNT_MASK32;
117     t->counthigh = count >> 32;
118 }
119 
120 // timer callback
121 static void slavio_timer_irq(void *opaque)
122 {
123     TimerContext *tc = opaque;
124     SLAVIO_TIMERState *s = tc->s;
125     CPUTimerState *t = &s->cputimer[tc->timer_index];
126 
127     slavio_timer_get_out(t);
128     trace_slavio_timer_irq(t->counthigh, t->count);
129     /* if limit is 0 (free-run), there will be no match */
130     if (t->limit != 0) {
131         t->reached = TIMER_REACHED;
132     }
133     /* there is no interrupt if user timer or free-run */
134     if (!slavio_timer_is_user(tc) && t->limit != 0) {
135         qemu_irq_raise(t->irq);
136     }
137 }
138 
139 static uint64_t slavio_timer_mem_readl(void *opaque, hwaddr addr,
140                                        unsigned size)
141 {
142     TimerContext *tc = opaque;
143     SLAVIO_TIMERState *s = tc->s;
144     uint32_t saddr, ret;
145     unsigned int timer_index = tc->timer_index;
146     CPUTimerState *t = &s->cputimer[timer_index];
147 
148     saddr = addr >> 2;
149     switch (saddr) {
150     case TIMER_LIMIT:
151         // read limit (system counter mode) or read most signifying
152         // part of counter (user mode)
153         if (slavio_timer_is_user(tc)) {
154             // read user timer MSW
155             slavio_timer_get_out(t);
156             ret = t->counthigh | t->reached;
157         } else {
158             // read limit
159             // clear irq
160             qemu_irq_lower(t->irq);
161             t->reached = 0;
162             ret = t->limit & TIMER_LIMIT_MASK32;
163         }
164         break;
165     case TIMER_COUNTER:
166         // read counter and reached bit (system mode) or read lsbits
167         // of counter (user mode)
168         slavio_timer_get_out(t);
169         if (slavio_timer_is_user(tc)) { // read user timer LSW
170             ret = t->count & TIMER_MAX_COUNT64;
171         } else { // read limit
172             ret = (t->count & TIMER_MAX_COUNT32) |
173                 t->reached;
174         }
175         break;
176     case TIMER_STATUS:
177         // only available in processor counter/timer
178         // read start/stop status
179         if (timer_index > 0) {
180             ret = t->run;
181         } else {
182             ret = 0;
183         }
184         break;
185     case TIMER_MODE:
186         // only available in system counter
187         // read user/system mode
188         ret = s->cputimer_mode;
189         break;
190     default:
191         trace_slavio_timer_mem_readl_invalid(addr);
192         ret = 0;
193         break;
194     }
195     trace_slavio_timer_mem_readl(addr, ret);
196     return ret;
197 }
198 
199 static void slavio_timer_mem_writel(void *opaque, hwaddr addr,
200                                     uint64_t val, unsigned size)
201 {
202     TimerContext *tc = opaque;
203     SLAVIO_TIMERState *s = tc->s;
204     uint32_t saddr;
205     unsigned int timer_index = tc->timer_index;
206     CPUTimerState *t = &s->cputimer[timer_index];
207 
208     trace_slavio_timer_mem_writel(addr, val);
209     saddr = addr >> 2;
210     switch (saddr) {
211     case TIMER_LIMIT:
212         if (slavio_timer_is_user(tc)) {
213             uint64_t count;
214 
215             // set user counter MSW, reset counter
216             t->limit = TIMER_MAX_COUNT64;
217             t->counthigh = val & (TIMER_MAX_COUNT64 >> 32);
218             t->reached = 0;
219             count = ((uint64_t)t->counthigh << 32) | t->count;
220             trace_slavio_timer_mem_writel_limit(timer_index, count);
221             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
222         } else {
223             // set limit, reset counter
224             qemu_irq_lower(t->irq);
225             t->limit = val & TIMER_MAX_COUNT32;
226             if (t->timer) {
227                 if (t->limit == 0) { /* free-run */
228                     ptimer_set_limit(t->timer,
229                                      LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
230                 } else {
231                     ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 1);
232                 }
233             }
234         }
235         break;
236     case TIMER_COUNTER:
237         if (slavio_timer_is_user(tc)) {
238             uint64_t count;
239 
240             // set user counter LSW, reset counter
241             t->limit = TIMER_MAX_COUNT64;
242             t->count = val & TIMER_MAX_COUNT64;
243             t->reached = 0;
244             count = ((uint64_t)t->counthigh) << 32 | t->count;
245             trace_slavio_timer_mem_writel_limit(timer_index, count);
246             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
247         } else {
248             trace_slavio_timer_mem_writel_counter_invalid();
249         }
250         break;
251     case TIMER_COUNTER_NORST:
252         // set limit without resetting counter
253         t->limit = val & TIMER_MAX_COUNT32;
254         if (t->limit == 0) { /* free-run */
255             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 0);
256         } else {
257             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 0);
258         }
259         break;
260     case TIMER_STATUS:
261         if (slavio_timer_is_user(tc)) {
262             // start/stop user counter
263             if (val & 1) {
264                 trace_slavio_timer_mem_writel_status_start(timer_index);
265                 ptimer_run(t->timer, 0);
266             } else {
267                 trace_slavio_timer_mem_writel_status_stop(timer_index);
268                 ptimer_stop(t->timer);
269             }
270         }
271         t->run = val & 1;
272         break;
273     case TIMER_MODE:
274         if (timer_index == 0) {
275             unsigned int i;
276 
277             for (i = 0; i < s->num_cpus; i++) {
278                 unsigned int processor = 1 << i;
279                 CPUTimerState *curr_timer = &s->cputimer[i + 1];
280 
281                 // check for a change in timer mode for this processor
282                 if ((val & processor) != (s->cputimer_mode & processor)) {
283                     if (val & processor) { // counter -> user timer
284                         qemu_irq_lower(curr_timer->irq);
285                         // counters are always running
286                         if (!curr_timer->run) {
287                             ptimer_stop(curr_timer->timer);
288                         }
289                         // user timer limit is always the same
290                         curr_timer->limit = TIMER_MAX_COUNT64;
291                         ptimer_set_limit(curr_timer->timer,
292                                          LIMIT_TO_PERIODS(curr_timer->limit),
293                                          1);
294                         // set this processors user timer bit in config
295                         // register
296                         s->cputimer_mode |= processor;
297                         trace_slavio_timer_mem_writel_mode_user(timer_index);
298                     } else { // user timer -> counter
299                         // start the counter
300                         ptimer_run(curr_timer->timer, 0);
301                         // clear this processors user timer bit in config
302                         // register
303                         s->cputimer_mode &= ~processor;
304                         trace_slavio_timer_mem_writel_mode_counter(timer_index);
305                     }
306                 }
307             }
308         } else {
309             trace_slavio_timer_mem_writel_mode_invalid();
310         }
311         break;
312     default:
313         trace_slavio_timer_mem_writel_invalid(addr);
314         break;
315     }
316 }
317 
318 static const MemoryRegionOps slavio_timer_mem_ops = {
319     .read = slavio_timer_mem_readl,
320     .write = slavio_timer_mem_writel,
321     .endianness = DEVICE_NATIVE_ENDIAN,
322     .valid = {
323         .min_access_size = 4,
324         .max_access_size = 4,
325     },
326 };
327 
328 static const VMStateDescription vmstate_timer = {
329     .name ="timer",
330     .version_id = 3,
331     .minimum_version_id = 3,
332     .fields = (VMStateField[]) {
333         VMSTATE_UINT64(limit, CPUTimerState),
334         VMSTATE_UINT32(count, CPUTimerState),
335         VMSTATE_UINT32(counthigh, CPUTimerState),
336         VMSTATE_UINT32(reached, CPUTimerState),
337         VMSTATE_UINT32(run    , CPUTimerState),
338         VMSTATE_PTIMER(timer, CPUTimerState),
339         VMSTATE_END_OF_LIST()
340     }
341 };
342 
343 static const VMStateDescription vmstate_slavio_timer = {
344     .name ="slavio_timer",
345     .version_id = 3,
346     .minimum_version_id = 3,
347     .fields = (VMStateField[]) {
348         VMSTATE_STRUCT_ARRAY(cputimer, SLAVIO_TIMERState, MAX_CPUS + 1, 3,
349                              vmstate_timer, CPUTimerState),
350         VMSTATE_END_OF_LIST()
351     }
352 };
353 
354 static void slavio_timer_reset(DeviceState *d)
355 {
356     SLAVIO_TIMERState *s = SLAVIO_TIMER(d);
357     unsigned int i;
358     CPUTimerState *curr_timer;
359 
360     for (i = 0; i <= MAX_CPUS; i++) {
361         curr_timer = &s->cputimer[i];
362         curr_timer->limit = 0;
363         curr_timer->count = 0;
364         curr_timer->reached = 0;
365         if (i <= s->num_cpus) {
366             ptimer_set_limit(curr_timer->timer,
367                              LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
368             ptimer_run(curr_timer->timer, 0);
369             curr_timer->run = 1;
370         }
371     }
372     s->cputimer_mode = 0;
373 }
374 
375 static void slavio_timer_init(Object *obj)
376 {
377     SLAVIO_TIMERState *s = SLAVIO_TIMER(obj);
378     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
379     QEMUBH *bh;
380     unsigned int i;
381     TimerContext *tc;
382 
383     for (i = 0; i <= MAX_CPUS; i++) {
384         uint64_t size;
385         char timer_name[20];
386 
387         tc = g_malloc0(sizeof(TimerContext));
388         tc->s = s;
389         tc->timer_index = i;
390 
391         bh = qemu_bh_new(slavio_timer_irq, tc);
392         s->cputimer[i].timer = ptimer_init(bh, PTIMER_POLICY_DEFAULT);
393         ptimer_set_period(s->cputimer[i].timer, TIMER_PERIOD);
394 
395         size = i == 0 ? SYS_TIMER_SIZE : CPU_TIMER_SIZE;
396         snprintf(timer_name, sizeof(timer_name), "timer-%i", i);
397         memory_region_init_io(&tc->iomem, obj, &slavio_timer_mem_ops, tc,
398                               timer_name, size);
399         sysbus_init_mmio(dev, &tc->iomem);
400 
401         sysbus_init_irq(dev, &s->cputimer[i].irq);
402     }
403 }
404 
405 static Property slavio_timer_properties[] = {
406     DEFINE_PROP_UINT32("num_cpus",  SLAVIO_TIMERState, num_cpus,  0),
407     DEFINE_PROP_END_OF_LIST(),
408 };
409 
410 static void slavio_timer_class_init(ObjectClass *klass, void *data)
411 {
412     DeviceClass *dc = DEVICE_CLASS(klass);
413 
414     dc->reset = slavio_timer_reset;
415     dc->vmsd = &vmstate_slavio_timer;
416     dc->props = slavio_timer_properties;
417 }
418 
419 static const TypeInfo slavio_timer_info = {
420     .name          = TYPE_SLAVIO_TIMER,
421     .parent        = TYPE_SYS_BUS_DEVICE,
422     .instance_size = sizeof(SLAVIO_TIMERState),
423     .instance_init = slavio_timer_init,
424     .class_init    = slavio_timer_class_init,
425 };
426 
427 static void slavio_timer_register_types(void)
428 {
429     type_register_static(&slavio_timer_info);
430 }
431 
432 type_init(slavio_timer_register_types)
433