1 /*
2 * PCM timer handling on ctxfi
3 *
4 * This source file is released under GPL v2 license (no other versions).
5 * See the COPYING file included in the main directory of this source
6 * distribution for the license terms and conditions.
7 */
8
9 #include <linux/slab.h>
10 #include <linux/math64.h>
11 #include <linux/moduleparam.h>
12 #include <sound/core.h>
13 #include <sound/pcm.h>
14 #include "ctatc.h"
15 #include "cthardware.h"
16 #include "cttimer.h"
17
18 static bool use_system_timer;
19 MODULE_PARM_DESC(use_system_timer, "Force to use system-timer");
20 module_param(use_system_timer, bool, S_IRUGO);
21
22 struct ct_timer_ops {
23 void (*init)(struct ct_timer_instance *);
24 void (*prepare)(struct ct_timer_instance *);
25 void (*start)(struct ct_timer_instance *);
26 void (*stop)(struct ct_timer_instance *);
27 void (*free_instance)(struct ct_timer_instance *);
28 void (*interrupt)(struct ct_timer *);
29 void (*free_global)(struct ct_timer *);
30 };
31
32 /* timer instance -- assigned to each PCM stream */
33 struct ct_timer_instance {
34 spinlock_t lock;
35 struct ct_timer *timer_base;
36 struct ct_atc_pcm *apcm;
37 struct snd_pcm_substream *substream;
38 struct timer_list timer;
39 struct list_head instance_list;
40 struct list_head running_list;
41 unsigned int position;
42 unsigned int frag_count;
43 unsigned int running:1;
44 unsigned int need_update:1;
45 };
46
47 /* timer instance manager */
48 struct ct_timer {
49 spinlock_t lock; /* global timer lock (for xfitimer) */
50 spinlock_t list_lock; /* lock for instance list */
51 struct ct_atc *atc;
52 struct ct_timer_ops *ops;
53 struct list_head instance_head;
54 struct list_head running_head;
55 unsigned int wc; /* current wallclock */
56 unsigned int irq_handling:1; /* in IRQ handling */
57 unsigned int reprogram:1; /* need to reprogram the internval */
58 unsigned int running:1; /* global timer running */
59 };
60
61
62 /*
63 * system-timer-based updates
64 */
65
ct_systimer_callback(unsigned long data)66 static void ct_systimer_callback(unsigned long data)
67 {
68 struct ct_timer_instance *ti = (struct ct_timer_instance *)data;
69 struct snd_pcm_substream *substream = ti->substream;
70 struct snd_pcm_runtime *runtime = substream->runtime;
71 struct ct_atc_pcm *apcm = ti->apcm;
72 unsigned int period_size = runtime->period_size;
73 unsigned int buffer_size = runtime->buffer_size;
74 unsigned long flags;
75 unsigned int position, dist, interval;
76
77 position = substream->ops->pointer(substream);
78 dist = (position + buffer_size - ti->position) % buffer_size;
79 if (dist >= period_size ||
80 position / period_size != ti->position / period_size) {
81 apcm->interrupt(apcm);
82 ti->position = position;
83 }
84 /* Add extra HZ*5/1000 to avoid overrun issue when recording
85 * at 8kHz in 8-bit format or at 88kHz in 24-bit format. */
86 interval = ((period_size - (position % period_size))
87 * HZ + (runtime->rate - 1)) / runtime->rate + HZ * 5 / 1000;
88 spin_lock_irqsave(&ti->lock, flags);
89 if (ti->running)
90 mod_timer(&ti->timer, jiffies + interval);
91 spin_unlock_irqrestore(&ti->lock, flags);
92 }
93
ct_systimer_init(struct ct_timer_instance * ti)94 static void ct_systimer_init(struct ct_timer_instance *ti)
95 {
96 setup_timer(&ti->timer, ct_systimer_callback,
97 (unsigned long)ti);
98 }
99
ct_systimer_start(struct ct_timer_instance * ti)100 static void ct_systimer_start(struct ct_timer_instance *ti)
101 {
102 struct snd_pcm_runtime *runtime = ti->substream->runtime;
103 unsigned long flags;
104
105 spin_lock_irqsave(&ti->lock, flags);
106 ti->running = 1;
107 mod_timer(&ti->timer,
108 jiffies + (runtime->period_size * HZ +
109 (runtime->rate - 1)) / runtime->rate);
110 spin_unlock_irqrestore(&ti->lock, flags);
111 }
112
ct_systimer_stop(struct ct_timer_instance * ti)113 static void ct_systimer_stop(struct ct_timer_instance *ti)
114 {
115 unsigned long flags;
116
117 spin_lock_irqsave(&ti->lock, flags);
118 ti->running = 0;
119 del_timer(&ti->timer);
120 spin_unlock_irqrestore(&ti->lock, flags);
121 }
122
ct_systimer_prepare(struct ct_timer_instance * ti)123 static void ct_systimer_prepare(struct ct_timer_instance *ti)
124 {
125 ct_systimer_stop(ti);
126 try_to_del_timer_sync(&ti->timer);
127 }
128
129 #define ct_systimer_free ct_systimer_prepare
130
131 static struct ct_timer_ops ct_systimer_ops = {
132 .init = ct_systimer_init,
133 .free_instance = ct_systimer_free,
134 .prepare = ct_systimer_prepare,
135 .start = ct_systimer_start,
136 .stop = ct_systimer_stop,
137 };
138
139
140 /*
141 * Handling multiple streams using a global emu20k1 timer irq
142 */
143
144 #define CT_TIMER_FREQ 48000
145 #define MIN_TICKS 1
146 #define MAX_TICKS ((1 << 13) - 1)
147
ct_xfitimer_irq_rearm(struct ct_timer * atimer,int ticks)148 static void ct_xfitimer_irq_rearm(struct ct_timer *atimer, int ticks)
149 {
150 struct hw *hw = atimer->atc->hw;
151 if (ticks > MAX_TICKS)
152 ticks = MAX_TICKS;
153 hw->set_timer_tick(hw, ticks);
154 if (!atimer->running)
155 hw->set_timer_irq(hw, 1);
156 atimer->running = 1;
157 }
158
ct_xfitimer_irq_stop(struct ct_timer * atimer)159 static void ct_xfitimer_irq_stop(struct ct_timer *atimer)
160 {
161 if (atimer->running) {
162 struct hw *hw = atimer->atc->hw;
163 hw->set_timer_irq(hw, 0);
164 hw->set_timer_tick(hw, 0);
165 atimer->running = 0;
166 }
167 }
168
ct_xfitimer_get_wc(struct ct_timer * atimer)169 static inline unsigned int ct_xfitimer_get_wc(struct ct_timer *atimer)
170 {
171 struct hw *hw = atimer->atc->hw;
172 return hw->get_wc(hw);
173 }
174
175 /*
176 * reprogram the timer interval;
177 * checks the running instance list and determines the next timer interval.
178 * also updates the each stream position, returns the number of streams
179 * to call snd_pcm_period_elapsed() appropriately
180 *
181 * call this inside the lock and irq disabled
182 */
ct_xfitimer_reprogram(struct ct_timer * atimer,int can_update)183 static int ct_xfitimer_reprogram(struct ct_timer *atimer, int can_update)
184 {
185 struct ct_timer_instance *ti;
186 unsigned int min_intr = (unsigned int)-1;
187 int updates = 0;
188 unsigned int wc, diff;
189
190 if (list_empty(&atimer->running_head)) {
191 ct_xfitimer_irq_stop(atimer);
192 atimer->reprogram = 0; /* clear flag */
193 return 0;
194 }
195
196 wc = ct_xfitimer_get_wc(atimer);
197 diff = wc - atimer->wc;
198 atimer->wc = wc;
199 list_for_each_entry(ti, &atimer->running_head, running_list) {
200 if (ti->frag_count > diff)
201 ti->frag_count -= diff;
202 else {
203 unsigned int pos;
204 unsigned int period_size, rate;
205
206 period_size = ti->substream->runtime->period_size;
207 rate = ti->substream->runtime->rate;
208 pos = ti->substream->ops->pointer(ti->substream);
209 if (pos / period_size != ti->position / period_size) {
210 ti->need_update = 1;
211 ti->position = pos;
212 updates++;
213 }
214 pos %= period_size;
215 pos = period_size - pos;
216 ti->frag_count = div_u64((u64)pos * CT_TIMER_FREQ +
217 rate - 1, rate);
218 }
219 if (ti->need_update && !can_update)
220 min_intr = 0; /* pending to the next irq */
221 if (ti->frag_count < min_intr)
222 min_intr = ti->frag_count;
223 }
224
225 if (min_intr < MIN_TICKS)
226 min_intr = MIN_TICKS;
227 ct_xfitimer_irq_rearm(atimer, min_intr);
228 atimer->reprogram = 0; /* clear flag */
229 return updates;
230 }
231
232 /* look through the instance list and call period_elapsed if needed */
ct_xfitimer_check_period(struct ct_timer * atimer)233 static void ct_xfitimer_check_period(struct ct_timer *atimer)
234 {
235 struct ct_timer_instance *ti;
236 unsigned long flags;
237
238 spin_lock_irqsave(&atimer->list_lock, flags);
239 list_for_each_entry(ti, &atimer->instance_head, instance_list) {
240 if (ti->running && ti->need_update) {
241 ti->need_update = 0;
242 ti->apcm->interrupt(ti->apcm);
243 }
244 }
245 spin_unlock_irqrestore(&atimer->list_lock, flags);
246 }
247
248 /* Handle timer-interrupt */
ct_xfitimer_callback(struct ct_timer * atimer)249 static void ct_xfitimer_callback(struct ct_timer *atimer)
250 {
251 int update;
252 unsigned long flags;
253
254 spin_lock_irqsave(&atimer->lock, flags);
255 atimer->irq_handling = 1;
256 do {
257 update = ct_xfitimer_reprogram(atimer, 1);
258 spin_unlock(&atimer->lock);
259 if (update)
260 ct_xfitimer_check_period(atimer);
261 spin_lock(&atimer->lock);
262 } while (atimer->reprogram);
263 atimer->irq_handling = 0;
264 spin_unlock_irqrestore(&atimer->lock, flags);
265 }
266
ct_xfitimer_prepare(struct ct_timer_instance * ti)267 static void ct_xfitimer_prepare(struct ct_timer_instance *ti)
268 {
269 ti->frag_count = ti->substream->runtime->period_size;
270 ti->running = 0;
271 ti->need_update = 0;
272 }
273
274
275 /* start/stop the timer */
ct_xfitimer_update(struct ct_timer * atimer)276 static void ct_xfitimer_update(struct ct_timer *atimer)
277 {
278 unsigned long flags;
279
280 spin_lock_irqsave(&atimer->lock, flags);
281 if (atimer->irq_handling) {
282 /* reached from IRQ handler; let it handle later */
283 atimer->reprogram = 1;
284 spin_unlock_irqrestore(&atimer->lock, flags);
285 return;
286 }
287
288 ct_xfitimer_irq_stop(atimer);
289 ct_xfitimer_reprogram(atimer, 0);
290 spin_unlock_irqrestore(&atimer->lock, flags);
291 }
292
ct_xfitimer_start(struct ct_timer_instance * ti)293 static void ct_xfitimer_start(struct ct_timer_instance *ti)
294 {
295 struct ct_timer *atimer = ti->timer_base;
296 unsigned long flags;
297
298 spin_lock_irqsave(&atimer->lock, flags);
299 if (list_empty(&ti->running_list))
300 atimer->wc = ct_xfitimer_get_wc(atimer);
301 ti->running = 1;
302 ti->need_update = 0;
303 list_add(&ti->running_list, &atimer->running_head);
304 spin_unlock_irqrestore(&atimer->lock, flags);
305 ct_xfitimer_update(atimer);
306 }
307
ct_xfitimer_stop(struct ct_timer_instance * ti)308 static void ct_xfitimer_stop(struct ct_timer_instance *ti)
309 {
310 struct ct_timer *atimer = ti->timer_base;
311 unsigned long flags;
312
313 spin_lock_irqsave(&atimer->lock, flags);
314 list_del_init(&ti->running_list);
315 ti->running = 0;
316 spin_unlock_irqrestore(&atimer->lock, flags);
317 ct_xfitimer_update(atimer);
318 }
319
ct_xfitimer_free_global(struct ct_timer * atimer)320 static void ct_xfitimer_free_global(struct ct_timer *atimer)
321 {
322 ct_xfitimer_irq_stop(atimer);
323 }
324
325 static struct ct_timer_ops ct_xfitimer_ops = {
326 .prepare = ct_xfitimer_prepare,
327 .start = ct_xfitimer_start,
328 .stop = ct_xfitimer_stop,
329 .interrupt = ct_xfitimer_callback,
330 .free_global = ct_xfitimer_free_global,
331 };
332
333 /*
334 * timer instance
335 */
336
337 struct ct_timer_instance *
ct_timer_instance_new(struct ct_timer * atimer,struct ct_atc_pcm * apcm)338 ct_timer_instance_new(struct ct_timer *atimer, struct ct_atc_pcm *apcm)
339 {
340 struct ct_timer_instance *ti;
341
342 ti = kzalloc(sizeof(*ti), GFP_KERNEL);
343 if (!ti)
344 return NULL;
345 spin_lock_init(&ti->lock);
346 INIT_LIST_HEAD(&ti->instance_list);
347 INIT_LIST_HEAD(&ti->running_list);
348 ti->timer_base = atimer;
349 ti->apcm = apcm;
350 ti->substream = apcm->substream;
351 if (atimer->ops->init)
352 atimer->ops->init(ti);
353
354 spin_lock_irq(&atimer->list_lock);
355 list_add(&ti->instance_list, &atimer->instance_head);
356 spin_unlock_irq(&atimer->list_lock);
357
358 return ti;
359 }
360
ct_timer_prepare(struct ct_timer_instance * ti)361 void ct_timer_prepare(struct ct_timer_instance *ti)
362 {
363 if (ti->timer_base->ops->prepare)
364 ti->timer_base->ops->prepare(ti);
365 ti->position = 0;
366 ti->running = 0;
367 }
368
ct_timer_start(struct ct_timer_instance * ti)369 void ct_timer_start(struct ct_timer_instance *ti)
370 {
371 struct ct_timer *atimer = ti->timer_base;
372 atimer->ops->start(ti);
373 }
374
ct_timer_stop(struct ct_timer_instance * ti)375 void ct_timer_stop(struct ct_timer_instance *ti)
376 {
377 struct ct_timer *atimer = ti->timer_base;
378 atimer->ops->stop(ti);
379 }
380
ct_timer_instance_free(struct ct_timer_instance * ti)381 void ct_timer_instance_free(struct ct_timer_instance *ti)
382 {
383 struct ct_timer *atimer = ti->timer_base;
384
385 atimer->ops->stop(ti); /* to be sure */
386 if (atimer->ops->free_instance)
387 atimer->ops->free_instance(ti);
388
389 spin_lock_irq(&atimer->list_lock);
390 list_del(&ti->instance_list);
391 spin_unlock_irq(&atimer->list_lock);
392
393 kfree(ti);
394 }
395
396 /*
397 * timer manager
398 */
399
ct_timer_interrupt(void * data,unsigned int status)400 static void ct_timer_interrupt(void *data, unsigned int status)
401 {
402 struct ct_timer *timer = data;
403
404 /* Interval timer interrupt */
405 if ((status & IT_INT) && timer->ops->interrupt)
406 timer->ops->interrupt(timer);
407 }
408
ct_timer_new(struct ct_atc * atc)409 struct ct_timer *ct_timer_new(struct ct_atc *atc)
410 {
411 struct ct_timer *atimer;
412 struct hw *hw;
413
414 atimer = kzalloc(sizeof(*atimer), GFP_KERNEL);
415 if (!atimer)
416 return NULL;
417 spin_lock_init(&atimer->lock);
418 spin_lock_init(&atimer->list_lock);
419 INIT_LIST_HEAD(&atimer->instance_head);
420 INIT_LIST_HEAD(&atimer->running_head);
421 atimer->atc = atc;
422 hw = atc->hw;
423 if (!use_system_timer && hw->set_timer_irq) {
424 snd_printd(KERN_INFO "ctxfi: Use xfi-native timer\n");
425 atimer->ops = &ct_xfitimer_ops;
426 hw->irq_callback_data = atimer;
427 hw->irq_callback = ct_timer_interrupt;
428 } else {
429 snd_printd(KERN_INFO "ctxfi: Use system timer\n");
430 atimer->ops = &ct_systimer_ops;
431 }
432 return atimer;
433 }
434
ct_timer_free(struct ct_timer * atimer)435 void ct_timer_free(struct ct_timer *atimer)
436 {
437 struct hw *hw = atimer->atc->hw;
438 hw->irq_callback = NULL;
439 if (atimer->ops->free_global)
440 atimer->ops->free_global(atimer);
441 kfree(atimer);
442 }
443
444