xref: /openbmc/qemu/hw/timer/slavio_timer.c (revision 2c9b15ca)
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 "hw/sparc/sun4m.h"
26 #include "qemu/timer.h"
27 #include "hw/ptimer.h"
28 #include "hw/sysbus.h"
29 #include "trace.h"
30 
31 /*
32  * Registers of hardware timer in sun4m.
33  *
34  * This is the timer/counter part of chip STP2001 (Slave I/O), also
35  * produced as NCR89C105. See
36  * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR89C105.txt
37  *
38  * The 31-bit counter is incremented every 500ns by bit 9. Bits 8..0
39  * are zero. Bit 31 is 1 when count has been reached.
40  *
41  * Per-CPU timers interrupt local CPU, system timer uses normal
42  * interrupt routing.
43  *
44  */
45 
46 #define MAX_CPUS 16
47 
48 typedef struct CPUTimerState {
49     qemu_irq irq;
50     ptimer_state *timer;
51     uint32_t count, counthigh, reached;
52     /* processor only */
53     uint32_t running;
54     uint64_t limit;
55 } CPUTimerState;
56 
57 typedef struct SLAVIO_TIMERState {
58     SysBusDevice busdev;
59     uint32_t num_cpus;
60     uint32_t cputimer_mode;
61     CPUTimerState cputimer[MAX_CPUS + 1];
62 } SLAVIO_TIMERState;
63 
64 typedef struct TimerContext {
65     MemoryRegion iomem;
66     SLAVIO_TIMERState *s;
67     unsigned int timer_index; /* 0 for system, 1 ... MAX_CPUS for CPU timers */
68 } TimerContext;
69 
70 #define SYS_TIMER_SIZE 0x14
71 #define CPU_TIMER_SIZE 0x10
72 
73 #define TIMER_LIMIT         0
74 #define TIMER_COUNTER       1
75 #define TIMER_COUNTER_NORST 2
76 #define TIMER_STATUS        3
77 #define TIMER_MODE          4
78 
79 #define TIMER_COUNT_MASK32 0xfffffe00
80 #define TIMER_LIMIT_MASK32 0x7fffffff
81 #define TIMER_MAX_COUNT64  0x7ffffffffffffe00ULL
82 #define TIMER_MAX_COUNT32  0x7ffffe00ULL
83 #define TIMER_REACHED      0x80000000
84 #define TIMER_PERIOD       500ULL // 500ns
85 #define LIMIT_TO_PERIODS(l) (((l) >> 9) - 1)
86 #define PERIODS_TO_LIMIT(l) (((l) + 1) << 9)
87 
88 static int slavio_timer_is_user(TimerContext *tc)
89 {
90     SLAVIO_TIMERState *s = tc->s;
91     unsigned int timer_index = tc->timer_index;
92 
93     return timer_index != 0 && (s->cputimer_mode & (1 << (timer_index - 1)));
94 }
95 
96 // Update count, set irq, update expire_time
97 // Convert from ptimer countdown units
98 static void slavio_timer_get_out(CPUTimerState *t)
99 {
100     uint64_t count, limit;
101 
102     if (t->limit == 0) { /* free-run system or processor counter */
103         limit = TIMER_MAX_COUNT32;
104     } else {
105         limit = t->limit;
106     }
107     count = limit - PERIODS_TO_LIMIT(ptimer_get_count(t->timer));
108 
109     trace_slavio_timer_get_out(t->limit, t->counthigh, t->count);
110     t->count = count & TIMER_COUNT_MASK32;
111     t->counthigh = count >> 32;
112 }
113 
114 // timer callback
115 static void slavio_timer_irq(void *opaque)
116 {
117     TimerContext *tc = opaque;
118     SLAVIO_TIMERState *s = tc->s;
119     CPUTimerState *t = &s->cputimer[tc->timer_index];
120 
121     slavio_timer_get_out(t);
122     trace_slavio_timer_irq(t->counthigh, t->count);
123     /* if limit is 0 (free-run), there will be no match */
124     if (t->limit != 0) {
125         t->reached = TIMER_REACHED;
126     }
127     /* there is no interrupt if user timer or free-run */
128     if (!slavio_timer_is_user(tc) && t->limit != 0) {
129         qemu_irq_raise(t->irq);
130     }
131 }
132 
133 static uint64_t slavio_timer_mem_readl(void *opaque, hwaddr addr,
134                                        unsigned size)
135 {
136     TimerContext *tc = opaque;
137     SLAVIO_TIMERState *s = tc->s;
138     uint32_t saddr, ret;
139     unsigned int timer_index = tc->timer_index;
140     CPUTimerState *t = &s->cputimer[timer_index];
141 
142     saddr = addr >> 2;
143     switch (saddr) {
144     case TIMER_LIMIT:
145         // read limit (system counter mode) or read most signifying
146         // part of counter (user mode)
147         if (slavio_timer_is_user(tc)) {
148             // read user timer MSW
149             slavio_timer_get_out(t);
150             ret = t->counthigh | t->reached;
151         } else {
152             // read limit
153             // clear irq
154             qemu_irq_lower(t->irq);
155             t->reached = 0;
156             ret = t->limit & TIMER_LIMIT_MASK32;
157         }
158         break;
159     case TIMER_COUNTER:
160         // read counter and reached bit (system mode) or read lsbits
161         // of counter (user mode)
162         slavio_timer_get_out(t);
163         if (slavio_timer_is_user(tc)) { // read user timer LSW
164             ret = t->count & TIMER_MAX_COUNT64;
165         } else { // read limit
166             ret = (t->count & TIMER_MAX_COUNT32) |
167                 t->reached;
168         }
169         break;
170     case TIMER_STATUS:
171         // only available in processor counter/timer
172         // read start/stop status
173         if (timer_index > 0) {
174             ret = t->running;
175         } else {
176             ret = 0;
177         }
178         break;
179     case TIMER_MODE:
180         // only available in system counter
181         // read user/system mode
182         ret = s->cputimer_mode;
183         break;
184     default:
185         trace_slavio_timer_mem_readl_invalid(addr);
186         ret = 0;
187         break;
188     }
189     trace_slavio_timer_mem_readl(addr, ret);
190     return ret;
191 }
192 
193 static void slavio_timer_mem_writel(void *opaque, hwaddr addr,
194                                     uint64_t val, unsigned size)
195 {
196     TimerContext *tc = opaque;
197     SLAVIO_TIMERState *s = tc->s;
198     uint32_t saddr;
199     unsigned int timer_index = tc->timer_index;
200     CPUTimerState *t = &s->cputimer[timer_index];
201 
202     trace_slavio_timer_mem_writel(addr, val);
203     saddr = addr >> 2;
204     switch (saddr) {
205     case TIMER_LIMIT:
206         if (slavio_timer_is_user(tc)) {
207             uint64_t count;
208 
209             // set user counter MSW, reset counter
210             t->limit = TIMER_MAX_COUNT64;
211             t->counthigh = val & (TIMER_MAX_COUNT64 >> 32);
212             t->reached = 0;
213             count = ((uint64_t)t->counthigh << 32) | t->count;
214             trace_slavio_timer_mem_writel_limit(timer_index, count);
215             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
216         } else {
217             // set limit, reset counter
218             qemu_irq_lower(t->irq);
219             t->limit = val & TIMER_MAX_COUNT32;
220             if (t->timer) {
221                 if (t->limit == 0) { /* free-run */
222                     ptimer_set_limit(t->timer,
223                                      LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
224                 } else {
225                     ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 1);
226                 }
227             }
228         }
229         break;
230     case TIMER_COUNTER:
231         if (slavio_timer_is_user(tc)) {
232             uint64_t count;
233 
234             // set user counter LSW, reset counter
235             t->limit = TIMER_MAX_COUNT64;
236             t->count = val & TIMER_MAX_COUNT64;
237             t->reached = 0;
238             count = ((uint64_t)t->counthigh) << 32 | t->count;
239             trace_slavio_timer_mem_writel_limit(timer_index, count);
240             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
241         } else {
242             trace_slavio_timer_mem_writel_counter_invalid();
243         }
244         break;
245     case TIMER_COUNTER_NORST:
246         // set limit without resetting counter
247         t->limit = val & TIMER_MAX_COUNT32;
248         if (t->limit == 0) { /* free-run */
249             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 0);
250         } else {
251             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 0);
252         }
253         break;
254     case TIMER_STATUS:
255         if (slavio_timer_is_user(tc)) {
256             // start/stop user counter
257             if ((val & 1) && !t->running) {
258                 trace_slavio_timer_mem_writel_status_start(timer_index);
259                 ptimer_run(t->timer, 0);
260                 t->running = 1;
261             } else if (!(val & 1) && t->running) {
262                 trace_slavio_timer_mem_writel_status_stop(timer_index);
263                 ptimer_stop(t->timer);
264                 t->running = 0;
265             }
266         }
267         break;
268     case TIMER_MODE:
269         if (timer_index == 0) {
270             unsigned int i;
271 
272             for (i = 0; i < s->num_cpus; i++) {
273                 unsigned int processor = 1 << i;
274                 CPUTimerState *curr_timer = &s->cputimer[i + 1];
275 
276                 // check for a change in timer mode for this processor
277                 if ((val & processor) != (s->cputimer_mode & processor)) {
278                     if (val & processor) { // counter -> user timer
279                         qemu_irq_lower(curr_timer->irq);
280                         // counters are always running
281                         ptimer_stop(curr_timer->timer);
282                         curr_timer->running = 0;
283                         // user timer limit is always the same
284                         curr_timer->limit = TIMER_MAX_COUNT64;
285                         ptimer_set_limit(curr_timer->timer,
286                                          LIMIT_TO_PERIODS(curr_timer->limit),
287                                          1);
288                         // set this processors user timer bit in config
289                         // register
290                         s->cputimer_mode |= processor;
291                         trace_slavio_timer_mem_writel_mode_user(timer_index);
292                     } else { // user timer -> counter
293                         // stop the user timer if it is running
294                         if (curr_timer->running) {
295                             ptimer_stop(curr_timer->timer);
296                         }
297                         // start the counter
298                         ptimer_run(curr_timer->timer, 0);
299                         curr_timer->running = 1;
300                         // clear this processors user timer bit in config
301                         // register
302                         s->cputimer_mode &= ~processor;
303                         trace_slavio_timer_mem_writel_mode_counter(timer_index);
304                     }
305                 }
306             }
307         } else {
308             trace_slavio_timer_mem_writel_mode_invalid();
309         }
310         break;
311     default:
312         trace_slavio_timer_mem_writel_invalid(addr);
313         break;
314     }
315 }
316 
317 static const MemoryRegionOps slavio_timer_mem_ops = {
318     .read = slavio_timer_mem_readl,
319     .write = slavio_timer_mem_writel,
320     .endianness = DEVICE_NATIVE_ENDIAN,
321     .valid = {
322         .min_access_size = 4,
323         .max_access_size = 4,
324     },
325 };
326 
327 static const VMStateDescription vmstate_timer = {
328     .name ="timer",
329     .version_id = 3,
330     .minimum_version_id = 3,
331     .minimum_version_id_old = 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(running, 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     .minimum_version_id_old = 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 = container_of(d, SLAVIO_TIMERState, busdev.qdev);
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->running = 1;
371         }
372     }
373     s->cputimer_mode = 0;
374 }
375 
376 static int slavio_timer_init1(SysBusDevice *dev)
377 {
378     SLAVIO_TIMERState *s = FROM_SYSBUS(SLAVIO_TIMERState, dev);
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);
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, NULL, &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     return 0;
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     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
416 
417     k->init = slavio_timer_init1;
418     dc->reset = slavio_timer_reset;
419     dc->vmsd = &vmstate_slavio_timer;
420     dc->props = slavio_timer_properties;
421 }
422 
423 static const TypeInfo slavio_timer_info = {
424     .name          = "slavio_timer",
425     .parent        = TYPE_SYS_BUS_DEVICE,
426     .instance_size = sizeof(SLAVIO_TIMERState),
427     .class_init    = slavio_timer_class_init,
428 };
429 
430 static void slavio_timer_register_types(void)
431 {
432     type_register_static(&slavio_timer_info);
433 }
434 
435 type_init(slavio_timer_register_types)
436