xref: /openbmc/qemu/hw/timer/slavio_timer.c (revision e1ecf8c8)
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/qdev-properties.h"
30 #include "hw/sysbus.h"
31 #include "migration/vmstate.h"
32 #include "trace.h"
33 #include "qemu/main-loop.h"
34 #include "qemu/module.h"
35 
36 /*
37  * Registers of hardware timer in sun4m.
38  *
39  * This is the timer/counter part of chip STP2001 (Slave I/O), also
40  * produced as NCR89C105. See
41  * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR89C105.txt
42  *
43  * The 31-bit counter is incremented every 500ns by bit 9. Bits 8..0
44  * are zero. Bit 31 is 1 when count has been reached.
45  *
46  * Per-CPU timers interrupt local CPU, system timer uses normal
47  * interrupt routing.
48  *
49  */
50 
51 #define MAX_CPUS 16
52 
53 typedef struct CPUTimerState {
54     qemu_irq irq;
55     ptimer_state *timer;
56     uint32_t count, counthigh, reached;
57     /* processor only */
58     uint32_t run;
59     uint64_t limit;
60 } CPUTimerState;
61 
62 #define TYPE_SLAVIO_TIMER "slavio_timer"
63 #define SLAVIO_TIMER(obj) \
64     OBJECT_CHECK(SLAVIO_TIMERState, (obj), TYPE_SLAVIO_TIMER)
65 
66 typedef struct SLAVIO_TIMERState {
67     SysBusDevice parent_obj;
68 
69     uint32_t num_cpus;
70     uint32_t cputimer_mode;
71     CPUTimerState cputimer[MAX_CPUS + 1];
72 } SLAVIO_TIMERState;
73 
74 typedef struct TimerContext {
75     MemoryRegion iomem;
76     SLAVIO_TIMERState *s;
77     unsigned int timer_index; /* 0 for system, 1 ... MAX_CPUS for CPU timers */
78 } TimerContext;
79 
80 #define SYS_TIMER_SIZE 0x14
81 #define CPU_TIMER_SIZE 0x10
82 
83 #define TIMER_LIMIT         0
84 #define TIMER_COUNTER       1
85 #define TIMER_COUNTER_NORST 2
86 #define TIMER_STATUS        3
87 #define TIMER_MODE          4
88 
89 #define TIMER_COUNT_MASK32 0xfffffe00
90 #define TIMER_LIMIT_MASK32 0x7fffffff
91 #define TIMER_MAX_COUNT64  0x7ffffffffffffe00ULL
92 #define TIMER_MAX_COUNT32  0x7ffffe00ULL
93 #define TIMER_REACHED      0x80000000
94 #define TIMER_PERIOD       500ULL // 500ns
95 #define LIMIT_TO_PERIODS(l) (((l) >> 9) - 1)
96 #define PERIODS_TO_LIMIT(l) (((l) + 1) << 9)
97 
98 static int slavio_timer_is_user(TimerContext *tc)
99 {
100     SLAVIO_TIMERState *s = tc->s;
101     unsigned int timer_index = tc->timer_index;
102 
103     return timer_index != 0 && (s->cputimer_mode & (1 << (timer_index - 1)));
104 }
105 
106 // Update count, set irq, update expire_time
107 // Convert from ptimer countdown units
108 static void slavio_timer_get_out(CPUTimerState *t)
109 {
110     uint64_t count, limit;
111 
112     if (t->limit == 0) { /* free-run system or processor counter */
113         limit = TIMER_MAX_COUNT32;
114     } else {
115         limit = t->limit;
116     }
117     count = limit - PERIODS_TO_LIMIT(ptimer_get_count(t->timer));
118 
119     trace_slavio_timer_get_out(t->limit, t->counthigh, t->count);
120     t->count = count & TIMER_COUNT_MASK32;
121     t->counthigh = count >> 32;
122 }
123 
124 // timer callback
125 static void slavio_timer_irq(void *opaque)
126 {
127     TimerContext *tc = opaque;
128     SLAVIO_TIMERState *s = tc->s;
129     CPUTimerState *t = &s->cputimer[tc->timer_index];
130 
131     slavio_timer_get_out(t);
132     trace_slavio_timer_irq(t->counthigh, t->count);
133     /* if limit is 0 (free-run), there will be no match */
134     if (t->limit != 0) {
135         t->reached = TIMER_REACHED;
136     }
137     /* there is no interrupt if user timer or free-run */
138     if (!slavio_timer_is_user(tc) && t->limit != 0) {
139         qemu_irq_raise(t->irq);
140     }
141 }
142 
143 static uint64_t slavio_timer_mem_readl(void *opaque, hwaddr addr,
144                                        unsigned size)
145 {
146     TimerContext *tc = opaque;
147     SLAVIO_TIMERState *s = tc->s;
148     uint32_t saddr, ret;
149     unsigned int timer_index = tc->timer_index;
150     CPUTimerState *t = &s->cputimer[timer_index];
151 
152     saddr = addr >> 2;
153     switch (saddr) {
154     case TIMER_LIMIT:
155         // read limit (system counter mode) or read most signifying
156         // part of counter (user mode)
157         if (slavio_timer_is_user(tc)) {
158             // read user timer MSW
159             slavio_timer_get_out(t);
160             ret = t->counthigh | t->reached;
161         } else {
162             // read limit
163             // clear irq
164             qemu_irq_lower(t->irq);
165             t->reached = 0;
166             ret = t->limit & TIMER_LIMIT_MASK32;
167         }
168         break;
169     case TIMER_COUNTER:
170         // read counter and reached bit (system mode) or read lsbits
171         // of counter (user mode)
172         slavio_timer_get_out(t);
173         if (slavio_timer_is_user(tc)) { // read user timer LSW
174             ret = t->count & TIMER_MAX_COUNT64;
175         } else { // read limit
176             ret = (t->count & TIMER_MAX_COUNT32) |
177                 t->reached;
178         }
179         break;
180     case TIMER_STATUS:
181         // only available in processor counter/timer
182         // read start/stop status
183         if (timer_index > 0) {
184             ret = t->run;
185         } else {
186             ret = 0;
187         }
188         break;
189     case TIMER_MODE:
190         // only available in system counter
191         // read user/system mode
192         ret = s->cputimer_mode;
193         break;
194     default:
195         trace_slavio_timer_mem_readl_invalid(addr);
196         ret = 0;
197         break;
198     }
199     trace_slavio_timer_mem_readl(addr, ret);
200     return ret;
201 }
202 
203 static void slavio_timer_mem_writel(void *opaque, hwaddr addr,
204                                     uint64_t val, unsigned size)
205 {
206     TimerContext *tc = opaque;
207     SLAVIO_TIMERState *s = tc->s;
208     uint32_t saddr;
209     unsigned int timer_index = tc->timer_index;
210     CPUTimerState *t = &s->cputimer[timer_index];
211 
212     trace_slavio_timer_mem_writel(addr, val);
213     saddr = addr >> 2;
214     switch (saddr) {
215     case TIMER_LIMIT:
216         if (slavio_timer_is_user(tc)) {
217             uint64_t count;
218 
219             // set user counter MSW, reset counter
220             t->limit = TIMER_MAX_COUNT64;
221             t->counthigh = val & (TIMER_MAX_COUNT64 >> 32);
222             t->reached = 0;
223             count = ((uint64_t)t->counthigh << 32) | t->count;
224             trace_slavio_timer_mem_writel_limit(timer_index, count);
225             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
226         } else {
227             // set limit, reset counter
228             qemu_irq_lower(t->irq);
229             t->limit = val & TIMER_MAX_COUNT32;
230             if (t->timer) {
231                 if (t->limit == 0) { /* free-run */
232                     ptimer_set_limit(t->timer,
233                                      LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
234                 } else {
235                     ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 1);
236                 }
237             }
238         }
239         break;
240     case TIMER_COUNTER:
241         if (slavio_timer_is_user(tc)) {
242             uint64_t count;
243 
244             // set user counter LSW, reset counter
245             t->limit = TIMER_MAX_COUNT64;
246             t->count = val & TIMER_MAX_COUNT64;
247             t->reached = 0;
248             count = ((uint64_t)t->counthigh) << 32 | t->count;
249             trace_slavio_timer_mem_writel_limit(timer_index, count);
250             ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));
251         } else {
252             trace_slavio_timer_mem_writel_counter_invalid();
253         }
254         break;
255     case TIMER_COUNTER_NORST:
256         // set limit without resetting counter
257         t->limit = val & TIMER_MAX_COUNT32;
258         if (t->limit == 0) { /* free-run */
259             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 0);
260         } else {
261             ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 0);
262         }
263         break;
264     case TIMER_STATUS:
265         if (slavio_timer_is_user(tc)) {
266             // start/stop user counter
267             if (val & 1) {
268                 trace_slavio_timer_mem_writel_status_start(timer_index);
269                 ptimer_run(t->timer, 0);
270             } else {
271                 trace_slavio_timer_mem_writel_status_stop(timer_index);
272                 ptimer_stop(t->timer);
273             }
274         }
275         t->run = val & 1;
276         break;
277     case TIMER_MODE:
278         if (timer_index == 0) {
279             unsigned int i;
280 
281             for (i = 0; i < s->num_cpus; i++) {
282                 unsigned int processor = 1 << i;
283                 CPUTimerState *curr_timer = &s->cputimer[i + 1];
284 
285                 // check for a change in timer mode for this processor
286                 if ((val & processor) != (s->cputimer_mode & processor)) {
287                     if (val & processor) { // counter -> user timer
288                         qemu_irq_lower(curr_timer->irq);
289                         // counters are always running
290                         if (!curr_timer->run) {
291                             ptimer_stop(curr_timer->timer);
292                         }
293                         // user timer limit is always the same
294                         curr_timer->limit = TIMER_MAX_COUNT64;
295                         ptimer_set_limit(curr_timer->timer,
296                                          LIMIT_TO_PERIODS(curr_timer->limit),
297                                          1);
298                         // set this processors user timer bit in config
299                         // register
300                         s->cputimer_mode |= processor;
301                         trace_slavio_timer_mem_writel_mode_user(timer_index);
302                     } else { // user timer -> counter
303                         // start the counter
304                         ptimer_run(curr_timer->timer, 0);
305                         // clear this processors user timer bit in config
306                         // register
307                         s->cputimer_mode &= ~processor;
308                         trace_slavio_timer_mem_writel_mode_counter(timer_index);
309                     }
310                 }
311             }
312         } else {
313             trace_slavio_timer_mem_writel_mode_invalid();
314         }
315         break;
316     default:
317         trace_slavio_timer_mem_writel_invalid(addr);
318         break;
319     }
320 }
321 
322 static const MemoryRegionOps slavio_timer_mem_ops = {
323     .read = slavio_timer_mem_readl,
324     .write = slavio_timer_mem_writel,
325     .endianness = DEVICE_NATIVE_ENDIAN,
326     .valid = {
327         .min_access_size = 4,
328         .max_access_size = 4,
329     },
330 };
331 
332 static const VMStateDescription vmstate_timer = {
333     .name ="timer",
334     .version_id = 3,
335     .minimum_version_id = 3,
336     .fields = (VMStateField[]) {
337         VMSTATE_UINT64(limit, CPUTimerState),
338         VMSTATE_UINT32(count, CPUTimerState),
339         VMSTATE_UINT32(counthigh, CPUTimerState),
340         VMSTATE_UINT32(reached, CPUTimerState),
341         VMSTATE_UINT32(run    , CPUTimerState),
342         VMSTATE_PTIMER(timer, CPUTimerState),
343         VMSTATE_END_OF_LIST()
344     }
345 };
346 
347 static const VMStateDescription vmstate_slavio_timer = {
348     .name ="slavio_timer",
349     .version_id = 3,
350     .minimum_version_id = 3,
351     .fields = (VMStateField[]) {
352         VMSTATE_STRUCT_ARRAY(cputimer, SLAVIO_TIMERState, MAX_CPUS + 1, 3,
353                              vmstate_timer, CPUTimerState),
354         VMSTATE_END_OF_LIST()
355     }
356 };
357 
358 static void slavio_timer_reset(DeviceState *d)
359 {
360     SLAVIO_TIMERState *s = SLAVIO_TIMER(d);
361     unsigned int i;
362     CPUTimerState *curr_timer;
363 
364     for (i = 0; i <= MAX_CPUS; i++) {
365         curr_timer = &s->cputimer[i];
366         curr_timer->limit = 0;
367         curr_timer->count = 0;
368         curr_timer->reached = 0;
369         if (i <= s->num_cpus) {
370             ptimer_set_limit(curr_timer->timer,
371                              LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
372             ptimer_run(curr_timer->timer, 0);
373             curr_timer->run = 1;
374         }
375     }
376     s->cputimer_mode = 0;
377 }
378 
379 static void slavio_timer_init(Object *obj)
380 {
381     SLAVIO_TIMERState *s = SLAVIO_TIMER(obj);
382     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
383     QEMUBH *bh;
384     unsigned int i;
385     TimerContext *tc;
386 
387     for (i = 0; i <= MAX_CPUS; i++) {
388         uint64_t size;
389         char timer_name[20];
390 
391         tc = g_malloc0(sizeof(TimerContext));
392         tc->s = s;
393         tc->timer_index = i;
394 
395         bh = qemu_bh_new(slavio_timer_irq, tc);
396         s->cputimer[i].timer = ptimer_init_with_bh(bh, PTIMER_POLICY_DEFAULT);
397         ptimer_set_period(s->cputimer[i].timer, TIMER_PERIOD);
398 
399         size = i == 0 ? SYS_TIMER_SIZE : CPU_TIMER_SIZE;
400         snprintf(timer_name, sizeof(timer_name), "timer-%i", i);
401         memory_region_init_io(&tc->iomem, obj, &slavio_timer_mem_ops, tc,
402                               timer_name, size);
403         sysbus_init_mmio(dev, &tc->iomem);
404 
405         sysbus_init_irq(dev, &s->cputimer[i].irq);
406     }
407 }
408 
409 static Property slavio_timer_properties[] = {
410     DEFINE_PROP_UINT32("num_cpus",  SLAVIO_TIMERState, num_cpus,  0),
411     DEFINE_PROP_END_OF_LIST(),
412 };
413 
414 static void slavio_timer_class_init(ObjectClass *klass, void *data)
415 {
416     DeviceClass *dc = DEVICE_CLASS(klass);
417 
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          = TYPE_SLAVIO_TIMER,
425     .parent        = TYPE_SYS_BUS_DEVICE,
426     .instance_size = sizeof(SLAVIO_TIMERState),
427     .instance_init = slavio_timer_init,
428     .class_init    = slavio_timer_class_init,
429 };
430 
431 static void slavio_timer_register_types(void)
432 {
433     type_register_static(&slavio_timer_info);
434 }
435 
436 type_init(slavio_timer_register_types)
437