xref: /openbmc/qemu/hw/timer/slavio_timer.c (revision a9ded601)
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 "hw/sparc/sun4m.h"
27 #include "qemu/timer.h"
28 #include "hw/ptimer.h"
29 #include "hw/sysbus.h"
30 #include "trace.h"
31 #include "qemu/main-loop.h"
32 
33 /*
34  * Registers of hardware timer in sun4m.
35  *
36  * This is the timer/counter part of chip STP2001 (Slave I/O), also
37  * produced as NCR89C105. See
38  * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR89C105.txt
39  *
40  * The 31-bit counter is incremented every 500ns by bit 9. Bits 8..0
41  * are zero. Bit 31 is 1 when count has been reached.
42  *
43  * Per-CPU timers interrupt local CPU, system timer uses normal
44  * interrupt routing.
45  *
46  */
47 
48 #define MAX_CPUS 16
49 
50 typedef struct CPUTimerState {
51     qemu_irq irq;
52     ptimer_state *timer;
53     uint32_t count, counthigh, reached;
54     /* processor only */
55     uint32_t run;
56     uint64_t limit;
57 } CPUTimerState;
58 
59 #define TYPE_SLAVIO_TIMER "slavio_timer"
60 #define SLAVIO_TIMER(obj) \
61     OBJECT_CHECK(SLAVIO_TIMERState, (obj), TYPE_SLAVIO_TIMER)
62 
63 typedef struct SLAVIO_TIMERState {
64     SysBusDevice parent_obj;
65 
66     uint32_t num_cpus;
67     uint32_t cputimer_mode;
68     CPUTimerState cputimer[MAX_CPUS + 1];
69 } SLAVIO_TIMERState;
70 
71 typedef struct TimerContext {
72     MemoryRegion iomem;
73     SLAVIO_TIMERState *s;
74     unsigned int timer_index; /* 0 for system, 1 ... MAX_CPUS for CPU timers */
75 } TimerContext;
76 
77 #define SYS_TIMER_SIZE 0x14
78 #define CPU_TIMER_SIZE 0x10
79 
80 #define TIMER_LIMIT         0
81 #define TIMER_COUNTER       1
82 #define TIMER_COUNTER_NORST 2
83 #define TIMER_STATUS        3
84 #define TIMER_MODE          4
85 
86 #define TIMER_COUNT_MASK32 0xfffffe00
87 #define TIMER_LIMIT_MASK32 0x7fffffff
88 #define TIMER_MAX_COUNT64  0x7ffffffffffffe00ULL
89 #define TIMER_MAX_COUNT32  0x7ffffe00ULL
90 #define TIMER_REACHED      0x80000000
91 #define TIMER_PERIOD       500ULL // 500ns
92 #define LIMIT_TO_PERIODS(l) (((l) >> 9) - 1)
93 #define PERIODS_TO_LIMIT(l) (((l) + 1) << 9)
94 
95 static int slavio_timer_is_user(TimerContext *tc)
96 {
97     SLAVIO_TIMERState *s = tc->s;
98     unsigned int timer_index = tc->timer_index;
99 
100     return timer_index != 0 && (s->cputimer_mode & (1 << (timer_index - 1)));
101 }
102 
103 // Update count, set irq, update expire_time
104 // Convert from ptimer countdown units
105 static void slavio_timer_get_out(CPUTimerState *t)
106 {
107     uint64_t count, limit;
108 
109     if (t->limit == 0) { /* free-run system or processor counter */
110         limit = TIMER_MAX_COUNT32;
111     } else {
112         limit = t->limit;
113     }
114     count = limit - PERIODS_TO_LIMIT(ptimer_get_count(t->timer));
115 
116     trace_slavio_timer_get_out(t->limit, t->counthigh, t->count);
117     t->count = count & TIMER_COUNT_MASK32;
118     t->counthigh = count >> 32;
119 }
120 
121 // timer callback
122 static void slavio_timer_irq(void *opaque)
123 {
124     TimerContext *tc = opaque;
125     SLAVIO_TIMERState *s = tc->s;
126     CPUTimerState *t = &s->cputimer[tc->timer_index];
127 
128     slavio_timer_get_out(t);
129     trace_slavio_timer_irq(t->counthigh, t->count);
130     /* if limit is 0 (free-run), there will be no match */
131     if (t->limit != 0) {
132         t->reached = TIMER_REACHED;
133     }
134     /* there is no interrupt if user timer or free-run */
135     if (!slavio_timer_is_user(tc) && t->limit != 0) {
136         qemu_irq_raise(t->irq);
137     }
138 }
139 
140 static uint64_t slavio_timer_mem_readl(void *opaque, hwaddr addr,
141                                        unsigned size)
142 {
143     TimerContext *tc = opaque;
144     SLAVIO_TIMERState *s = tc->s;
145     uint32_t saddr, ret;
146     unsigned int timer_index = tc->timer_index;
147     CPUTimerState *t = &s->cputimer[timer_index];
148 
149     saddr = addr >> 2;
150     switch (saddr) {
151     case TIMER_LIMIT:
152         // read limit (system counter mode) or read most signifying
153         // part of counter (user mode)
154         if (slavio_timer_is_user(tc)) {
155             // read user timer MSW
156             slavio_timer_get_out(t);
157             ret = t->counthigh | t->reached;
158         } else {
159             // read limit
160             // clear irq
161             qemu_irq_lower(t->irq);
162             t->reached = 0;
163             ret = t->limit & TIMER_LIMIT_MASK32;
164         }
165         break;
166     case TIMER_COUNTER:
167         // read counter and reached bit (system mode) or read lsbits
168         // of counter (user mode)
169         slavio_timer_get_out(t);
170         if (slavio_timer_is_user(tc)) { // read user timer LSW
171             ret = t->count & TIMER_MAX_COUNT64;
172         } else { // read limit
173             ret = (t->count & TIMER_MAX_COUNT32) |
174                 t->reached;
175         }
176         break;
177     case TIMER_STATUS:
178         // only available in processor counter/timer
179         // read start/stop status
180         if (timer_index > 0) {
181             ret = t->run;
182         } else {
183             ret = 0;
184         }
185         break;
186     case TIMER_MODE:
187         // only available in system counter
188         // read user/system mode
189         ret = s->cputimer_mode;
190         break;
191     default:
192         trace_slavio_timer_mem_readl_invalid(addr);
193         ret = 0;
194         break;
195     }
196     trace_slavio_timer_mem_readl(addr, ret);
197     return ret;
198 }
199 
200 static void slavio_timer_mem_writel(void *opaque, hwaddr addr,
201                                     uint64_t val, unsigned size)
202 {
203     TimerContext *tc = opaque;
204     SLAVIO_TIMERState *s = tc->s;
205     uint32_t saddr;
206     unsigned int timer_index = tc->timer_index;
207     CPUTimerState *t = &s->cputimer[timer_index];
208 
209     trace_slavio_timer_mem_writel(addr, val);
210     saddr = addr >> 2;
211     switch (saddr) {
212     case TIMER_LIMIT:
213         if (slavio_timer_is_user(tc)) {
214             uint64_t count;
215 
216             // set user counter MSW, reset counter
217             t->limit = TIMER_MAX_COUNT64;
218             t->counthigh = val & (TIMER_MAX_COUNT64 >> 32);
219             t->reached = 0;
220             count = ((uint64_t)t->counthigh << 32) | t->count;
221             trace_slavio_timer_mem_writel_limit(timer_index, count);
222             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
223         } else {
224             // set limit, reset counter
225             qemu_irq_lower(t->irq);
226             t->limit = val & TIMER_MAX_COUNT32;
227             if (t->timer) {
228                 if (t->limit == 0) { /* free-run */
229                     ptimer_set_limit(t->timer,
230                                      LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
231                 } else {
232                     ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 1);
233                 }
234             }
235         }
236         break;
237     case TIMER_COUNTER:
238         if (slavio_timer_is_user(tc)) {
239             uint64_t count;
240 
241             // set user counter LSW, reset counter
242             t->limit = TIMER_MAX_COUNT64;
243             t->count = val & TIMER_MAX_COUNT64;
244             t->reached = 0;
245             count = ((uint64_t)t->counthigh) << 32 | t->count;
246             trace_slavio_timer_mem_writel_limit(timer_index, count);
247             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
248         } else {
249             trace_slavio_timer_mem_writel_counter_invalid();
250         }
251         break;
252     case TIMER_COUNTER_NORST:
253         // set limit without resetting counter
254         t->limit = val & TIMER_MAX_COUNT32;
255         if (t->limit == 0) { /* free-run */
256             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 0);
257         } else {
258             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 0);
259         }
260         break;
261     case TIMER_STATUS:
262         if (slavio_timer_is_user(tc)) {
263             // start/stop user counter
264             if (val & 1) {
265                 trace_slavio_timer_mem_writel_status_start(timer_index);
266                 ptimer_run(t->timer, 0);
267             } else {
268                 trace_slavio_timer_mem_writel_status_stop(timer_index);
269                 ptimer_stop(t->timer);
270             }
271         }
272         t->run = val & 1;
273         break;
274     case TIMER_MODE:
275         if (timer_index == 0) {
276             unsigned int i;
277 
278             for (i = 0; i < s->num_cpus; i++) {
279                 unsigned int processor = 1 << i;
280                 CPUTimerState *curr_timer = &s->cputimer[i + 1];
281 
282                 // check for a change in timer mode for this processor
283                 if ((val & processor) != (s->cputimer_mode & processor)) {
284                     if (val & processor) { // counter -> user timer
285                         qemu_irq_lower(curr_timer->irq);
286                         // counters are always running
287                         if (!curr_timer->run) {
288                             ptimer_stop(curr_timer->timer);
289                         }
290                         // user timer limit is always the same
291                         curr_timer->limit = TIMER_MAX_COUNT64;
292                         ptimer_set_limit(curr_timer->timer,
293                                          LIMIT_TO_PERIODS(curr_timer->limit),
294                                          1);
295                         // set this processors user timer bit in config
296                         // register
297                         s->cputimer_mode |= processor;
298                         trace_slavio_timer_mem_writel_mode_user(timer_index);
299                     } else { // user timer -> counter
300                         // start the counter
301                         ptimer_run(curr_timer->timer, 0);
302                         // clear this processors user timer bit in config
303                         // register
304                         s->cputimer_mode &= ~processor;
305                         trace_slavio_timer_mem_writel_mode_counter(timer_index);
306                     }
307                 }
308             }
309         } else {
310             trace_slavio_timer_mem_writel_mode_invalid();
311         }
312         break;
313     default:
314         trace_slavio_timer_mem_writel_invalid(addr);
315         break;
316     }
317 }
318 
319 static const MemoryRegionOps slavio_timer_mem_ops = {
320     .read = slavio_timer_mem_readl,
321     .write = slavio_timer_mem_writel,
322     .endianness = DEVICE_NATIVE_ENDIAN,
323     .valid = {
324         .min_access_size = 4,
325         .max_access_size = 4,
326     },
327 };
328 
329 static const VMStateDescription vmstate_timer = {
330     .name ="timer",
331     .version_id = 3,
332     .minimum_version_id = 3,
333     .fields = (VMStateField[]) {
334         VMSTATE_UINT64(limit, CPUTimerState),
335         VMSTATE_UINT32(count, CPUTimerState),
336         VMSTATE_UINT32(counthigh, CPUTimerState),
337         VMSTATE_UINT32(reached, CPUTimerState),
338         VMSTATE_UINT32(run    , CPUTimerState),
339         VMSTATE_PTIMER(timer, CPUTimerState),
340         VMSTATE_END_OF_LIST()
341     }
342 };
343 
344 static const VMStateDescription vmstate_slavio_timer = {
345     .name ="slavio_timer",
346     .version_id = 3,
347     .minimum_version_id = 3,
348     .fields = (VMStateField[]) {
349         VMSTATE_STRUCT_ARRAY(cputimer, SLAVIO_TIMERState, MAX_CPUS + 1, 3,
350                              vmstate_timer, CPUTimerState),
351         VMSTATE_END_OF_LIST()
352     }
353 };
354 
355 static void slavio_timer_reset(DeviceState *d)
356 {
357     SLAVIO_TIMERState *s = SLAVIO_TIMER(d);
358     unsigned int i;
359     CPUTimerState *curr_timer;
360 
361     for (i = 0; i <= MAX_CPUS; i++) {
362         curr_timer = &s->cputimer[i];
363         curr_timer->limit = 0;
364         curr_timer->count = 0;
365         curr_timer->reached = 0;
366         if (i <= s->num_cpus) {
367             ptimer_set_limit(curr_timer->timer,
368                              LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
369             ptimer_run(curr_timer->timer, 0);
370             curr_timer->run = 1;
371         }
372     }
373     s->cputimer_mode = 0;
374 }
375 
376 static void slavio_timer_init(Object *obj)
377 {
378     SLAVIO_TIMERState *s = SLAVIO_TIMER(obj);
379     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
380     QEMUBH *bh;
381     unsigned int i;
382     TimerContext *tc;
383 
384     for (i = 0; i <= MAX_CPUS; i++) {
385         uint64_t size;
386         char timer_name[20];
387 
388         tc = g_malloc0(sizeof(TimerContext));
389         tc->s = s;
390         tc->timer_index = i;
391 
392         bh = qemu_bh_new(slavio_timer_irq, tc);
393         s->cputimer[i].timer = ptimer_init(bh, PTIMER_POLICY_DEFAULT);
394         ptimer_set_period(s->cputimer[i].timer, TIMER_PERIOD);
395 
396         size = i == 0 ? SYS_TIMER_SIZE : CPU_TIMER_SIZE;
397         snprintf(timer_name, sizeof(timer_name), "timer-%i", i);
398         memory_region_init_io(&tc->iomem, obj, &slavio_timer_mem_ops, tc,
399                               timer_name, size);
400         sysbus_init_mmio(dev, &tc->iomem);
401 
402         sysbus_init_irq(dev, &s->cputimer[i].irq);
403     }
404 }
405 
406 static Property slavio_timer_properties[] = {
407     DEFINE_PROP_UINT32("num_cpus",  SLAVIO_TIMERState, num_cpus,  0),
408     DEFINE_PROP_END_OF_LIST(),
409 };
410 
411 static void slavio_timer_class_init(ObjectClass *klass, void *data)
412 {
413     DeviceClass *dc = DEVICE_CLASS(klass);
414 
415     dc->reset = slavio_timer_reset;
416     dc->vmsd = &vmstate_slavio_timer;
417     dc->props = slavio_timer_properties;
418 }
419 
420 static const TypeInfo slavio_timer_info = {
421     .name          = TYPE_SLAVIO_TIMER,
422     .parent        = TYPE_SYS_BUS_DEVICE,
423     .instance_size = sizeof(SLAVIO_TIMERState),
424     .instance_init = slavio_timer_init,
425     .class_init    = slavio_timer_class_init,
426 };
427 
428 static void slavio_timer_register_types(void)
429 {
430     type_register_static(&slavio_timer_info);
431 }
432 
433 type_init(slavio_timer_register_types)
434