1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PCM timer handling on ctxfi
4 */
5
6#include <linux/slab.h>
7#include <linux/math64.h>
8#include <linux/moduleparam.h>
9#include <sound/core.h>
10#include <sound/pcm.h>
11#include "ctatc.h"
12#include "cthardware.h"
13#include "cttimer.h"
14
15static bool use_system_timer;
16MODULE_PARM_DESC(use_system_timer, "Force to use system-timer");
17module_param(use_system_timer, bool, 0444);
18
19struct ct_timer_ops {
20 void (*init)(struct ct_timer_instance *);
21 void (*prepare)(struct ct_timer_instance *);
22 void (*start)(struct ct_timer_instance *);
23 void (*stop)(struct ct_timer_instance *);
24 void (*free_instance)(struct ct_timer_instance *);
25 void (*interrupt)(struct ct_timer *);
26 void (*free_global)(struct ct_timer *);
27};
28
29/* timer instance -- assigned to each PCM stream */
30struct ct_timer_instance {
31 spinlock_t lock;
32 struct ct_timer *timer_base;
33 struct ct_atc_pcm *apcm;
34 struct snd_pcm_substream *substream;
35 struct timer_list timer;
36 struct list_head instance_list;
37 struct list_head running_list;
38 unsigned int position;
39 unsigned int frag_count;
40 unsigned int running:1;
41 unsigned int need_update:1;
42};
43
44/* timer instance manager */
45struct ct_timer {
46 spinlock_t lock; /* global timer lock (for xfitimer) */
47 spinlock_t list_lock; /* lock for instance list */
48 struct ct_atc *atc;
49 const struct ct_timer_ops *ops;
50 struct list_head instance_head;
51 struct list_head running_head;
52 unsigned int wc; /* current wallclock */
53 unsigned int irq_handling:1; /* in IRQ handling */
54 unsigned int reprogram:1; /* need to reprogram the internval */
55 unsigned int running:1; /* global timer running */
56};
57
58
59/*
60 * system-timer-based updates
61 */
62
63static void ct_systimer_callback(struct timer_list *t)
64{
65 struct ct_timer_instance *ti = from_timer(ti, t, timer);
66 struct snd_pcm_substream *substream = ti->substream;
67 struct snd_pcm_runtime *runtime = substream->runtime;
68 struct ct_atc_pcm *apcm = ti->apcm;
69 unsigned int period_size = runtime->period_size;
70 unsigned int buffer_size = runtime->buffer_size;
71 unsigned long flags;
72 unsigned int position, dist, interval;
73
74 position = substream->ops->pointer(substream);
75 dist = (position + buffer_size - ti->position) % buffer_size;
76 if (dist >= period_size ||
77 position / period_size != ti->position / period_size) {
78 apcm->interrupt(apcm);
79 ti->position = position;
80 }
81 /* Add extra HZ*5/1000 to avoid overrun issue when recording
82 * at 8kHz in 8-bit format or at 88kHz in 24-bit format. */
83 interval = ((period_size - (position % period_size))
84 * HZ + (runtime->rate - 1)) / runtime->rate + HZ * 5 / 1000;
85 spin_lock_irqsave(&ti->lock, flags);
86 if (ti->running)
87 mod_timer(timer: &ti->timer, expires: jiffies + interval);
88 spin_unlock_irqrestore(lock: &ti->lock, flags);
89}
90
91static void ct_systimer_init(struct ct_timer_instance *ti)
92{
93 timer_setup(&ti->timer, ct_systimer_callback, 0);
94}
95
96static void ct_systimer_start(struct ct_timer_instance *ti)
97{
98 struct snd_pcm_runtime *runtime = ti->substream->runtime;
99 unsigned long flags;
100
101 spin_lock_irqsave(&ti->lock, flags);
102 ti->running = 1;
103 mod_timer(timer: &ti->timer,
104 expires: jiffies + (runtime->period_size * HZ +
105 (runtime->rate - 1)) / runtime->rate);
106 spin_unlock_irqrestore(lock: &ti->lock, flags);
107}
108
109static void ct_systimer_stop(struct ct_timer_instance *ti)
110{
111 unsigned long flags;
112
113 spin_lock_irqsave(&ti->lock, flags);
114 ti->running = 0;
115 del_timer(timer: &ti->timer);
116 spin_unlock_irqrestore(lock: &ti->lock, flags);
117}
118
119static void ct_systimer_prepare(struct ct_timer_instance *ti)
120{
121 ct_systimer_stop(ti);
122 try_to_del_timer_sync(timer: &ti->timer);
123}
124
125#define ct_systimer_free ct_systimer_prepare
126
127static const struct ct_timer_ops ct_systimer_ops = {
128 .init = ct_systimer_init,
129 .free_instance = ct_systimer_free,
130 .prepare = ct_systimer_prepare,
131 .start = ct_systimer_start,
132 .stop = ct_systimer_stop,
133};
134
135
136/*
137 * Handling multiple streams using a global emu20k1 timer irq
138 */
139
140#define CT_TIMER_FREQ 48000
141#define MIN_TICKS 1
142#define MAX_TICKS ((1 << 13) - 1)
143
144static void ct_xfitimer_irq_rearm(struct ct_timer *atimer, int ticks)
145{
146 struct hw *hw = atimer->atc->hw;
147 if (ticks > MAX_TICKS)
148 ticks = MAX_TICKS;
149 hw->set_timer_tick(hw, ticks);
150 if (!atimer->running)
151 hw->set_timer_irq(hw, 1);
152 atimer->running = 1;
153}
154
155static void ct_xfitimer_irq_stop(struct ct_timer *atimer)
156{
157 if (atimer->running) {
158 struct hw *hw = atimer->atc->hw;
159 hw->set_timer_irq(hw, 0);
160 hw->set_timer_tick(hw, 0);
161 atimer->running = 0;
162 }
163}
164
165static inline unsigned int ct_xfitimer_get_wc(struct ct_timer *atimer)
166{
167 struct hw *hw = atimer->atc->hw;
168 return hw->get_wc(hw);
169}
170
171/*
172 * reprogram the timer interval;
173 * checks the running instance list and determines the next timer interval.
174 * also updates the each stream position, returns the number of streams
175 * to call snd_pcm_period_elapsed() appropriately
176 *
177 * call this inside the lock and irq disabled
178 */
179static int ct_xfitimer_reprogram(struct ct_timer *atimer, int can_update)
180{
181 struct ct_timer_instance *ti;
182 unsigned int min_intr = (unsigned int)-1;
183 int updates = 0;
184 unsigned int wc, diff;
185
186 if (list_empty(head: &atimer->running_head)) {
187 ct_xfitimer_irq_stop(atimer);
188 atimer->reprogram = 0; /* clear flag */
189 return 0;
190 }
191
192 wc = ct_xfitimer_get_wc(atimer);
193 diff = wc - atimer->wc;
194 atimer->wc = wc;
195 list_for_each_entry(ti, &atimer->running_head, running_list) {
196 if (ti->frag_count > diff)
197 ti->frag_count -= diff;
198 else {
199 unsigned int pos;
200 unsigned int period_size, rate;
201
202 period_size = ti->substream->runtime->period_size;
203 rate = ti->substream->runtime->rate;
204 pos = ti->substream->ops->pointer(ti->substream);
205 if (pos / period_size != ti->position / period_size) {
206 ti->need_update = 1;
207 ti->position = pos;
208 updates++;
209 }
210 pos %= period_size;
211 pos = period_size - pos;
212 ti->frag_count = div_u64(dividend: (u64)pos * CT_TIMER_FREQ +
213 rate - 1, divisor: rate);
214 }
215 if (ti->need_update && !can_update)
216 min_intr = 0; /* pending to the next irq */
217 if (ti->frag_count < min_intr)
218 min_intr = ti->frag_count;
219 }
220
221 if (min_intr < MIN_TICKS)
222 min_intr = MIN_TICKS;
223 ct_xfitimer_irq_rearm(atimer, ticks: min_intr);
224 atimer->reprogram = 0; /* clear flag */
225 return updates;
226}
227
228/* look through the instance list and call period_elapsed if needed */
229static void ct_xfitimer_check_period(struct ct_timer *atimer)
230{
231 struct ct_timer_instance *ti;
232 unsigned long flags;
233
234 spin_lock_irqsave(&atimer->list_lock, flags);
235 list_for_each_entry(ti, &atimer->instance_head, instance_list) {
236 if (ti->running && ti->need_update) {
237 ti->need_update = 0;
238 ti->apcm->interrupt(ti->apcm);
239 }
240 }
241 spin_unlock_irqrestore(lock: &atimer->list_lock, flags);
242}
243
244/* Handle timer-interrupt */
245static void ct_xfitimer_callback(struct ct_timer *atimer)
246{
247 int update;
248 unsigned long flags;
249
250 spin_lock_irqsave(&atimer->lock, flags);
251 atimer->irq_handling = 1;
252 do {
253 update = ct_xfitimer_reprogram(atimer, can_update: 1);
254 spin_unlock(lock: &atimer->lock);
255 if (update)
256 ct_xfitimer_check_period(atimer);
257 spin_lock(lock: &atimer->lock);
258 } while (atimer->reprogram);
259 atimer->irq_handling = 0;
260 spin_unlock_irqrestore(lock: &atimer->lock, flags);
261}
262
263static void ct_xfitimer_prepare(struct ct_timer_instance *ti)
264{
265 ti->frag_count = ti->substream->runtime->period_size;
266 ti->running = 0;
267 ti->need_update = 0;
268}
269
270
271/* start/stop the timer */
272static void ct_xfitimer_update(struct ct_timer *atimer)
273{
274 unsigned long flags;
275
276 spin_lock_irqsave(&atimer->lock, flags);
277 if (atimer->irq_handling) {
278 /* reached from IRQ handler; let it handle later */
279 atimer->reprogram = 1;
280 spin_unlock_irqrestore(lock: &atimer->lock, flags);
281 return;
282 }
283
284 ct_xfitimer_irq_stop(atimer);
285 ct_xfitimer_reprogram(atimer, can_update: 0);
286 spin_unlock_irqrestore(lock: &atimer->lock, flags);
287}
288
289static void ct_xfitimer_start(struct ct_timer_instance *ti)
290{
291 struct ct_timer *atimer = ti->timer_base;
292 unsigned long flags;
293
294 spin_lock_irqsave(&atimer->lock, flags);
295 if (list_empty(head: &ti->running_list))
296 atimer->wc = ct_xfitimer_get_wc(atimer);
297 ti->running = 1;
298 ti->need_update = 0;
299 list_add(new: &ti->running_list, head: &atimer->running_head);
300 spin_unlock_irqrestore(lock: &atimer->lock, flags);
301 ct_xfitimer_update(atimer);
302}
303
304static void ct_xfitimer_stop(struct ct_timer_instance *ti)
305{
306 struct ct_timer *atimer = ti->timer_base;
307 unsigned long flags;
308
309 spin_lock_irqsave(&atimer->lock, flags);
310 list_del_init(entry: &ti->running_list);
311 ti->running = 0;
312 spin_unlock_irqrestore(lock: &atimer->lock, flags);
313 ct_xfitimer_update(atimer);
314}
315
316static void ct_xfitimer_free_global(struct ct_timer *atimer)
317{
318 ct_xfitimer_irq_stop(atimer);
319}
320
321static const struct ct_timer_ops ct_xfitimer_ops = {
322 .prepare = ct_xfitimer_prepare,
323 .start = ct_xfitimer_start,
324 .stop = ct_xfitimer_stop,
325 .interrupt = ct_xfitimer_callback,
326 .free_global = ct_xfitimer_free_global,
327};
328
329/*
330 * timer instance
331 */
332
333struct ct_timer_instance *
334ct_timer_instance_new(struct ct_timer *atimer, struct ct_atc_pcm *apcm)
335{
336 struct ct_timer_instance *ti;
337
338 ti = kzalloc(size: sizeof(*ti), GFP_KERNEL);
339 if (!ti)
340 return NULL;
341 spin_lock_init(&ti->lock);
342 INIT_LIST_HEAD(list: &ti->instance_list);
343 INIT_LIST_HEAD(list: &ti->running_list);
344 ti->timer_base = atimer;
345 ti->apcm = apcm;
346 ti->substream = apcm->substream;
347 if (atimer->ops->init)
348 atimer->ops->init(ti);
349
350 spin_lock_irq(lock: &atimer->list_lock);
351 list_add(new: &ti->instance_list, head: &atimer->instance_head);
352 spin_unlock_irq(lock: &atimer->list_lock);
353
354 return ti;
355}
356
357void ct_timer_prepare(struct ct_timer_instance *ti)
358{
359 if (ti->timer_base->ops->prepare)
360 ti->timer_base->ops->prepare(ti);
361 ti->position = 0;
362 ti->running = 0;
363}
364
365void ct_timer_start(struct ct_timer_instance *ti)
366{
367 struct ct_timer *atimer = ti->timer_base;
368 atimer->ops->start(ti);
369}
370
371void ct_timer_stop(struct ct_timer_instance *ti)
372{
373 struct ct_timer *atimer = ti->timer_base;
374 atimer->ops->stop(ti);
375}
376
377void ct_timer_instance_free(struct ct_timer_instance *ti)
378{
379 struct ct_timer *atimer = ti->timer_base;
380
381 atimer->ops->stop(ti); /* to be sure */
382 if (atimer->ops->free_instance)
383 atimer->ops->free_instance(ti);
384
385 spin_lock_irq(lock: &atimer->list_lock);
386 list_del(entry: &ti->instance_list);
387 spin_unlock_irq(lock: &atimer->list_lock);
388
389 kfree(objp: ti);
390}
391
392/*
393 * timer manager
394 */
395
396static void ct_timer_interrupt(void *data, unsigned int status)
397{
398 struct ct_timer *timer = data;
399
400 /* Interval timer interrupt */
401 if ((status & IT_INT) && timer->ops->interrupt)
402 timer->ops->interrupt(timer);
403}
404
405struct ct_timer *ct_timer_new(struct ct_atc *atc)
406{
407 struct ct_timer *atimer;
408 struct hw *hw;
409
410 atimer = kzalloc(size: sizeof(*atimer), GFP_KERNEL);
411 if (!atimer)
412 return NULL;
413 spin_lock_init(&atimer->lock);
414 spin_lock_init(&atimer->list_lock);
415 INIT_LIST_HEAD(list: &atimer->instance_head);
416 INIT_LIST_HEAD(list: &atimer->running_head);
417 atimer->atc = atc;
418 hw = atc->hw;
419 if (!use_system_timer && hw->set_timer_irq) {
420 dev_info(atc->card->dev, "Use xfi-native timer\n");
421 atimer->ops = &ct_xfitimer_ops;
422 hw->irq_callback_data = atimer;
423 hw->irq_callback = ct_timer_interrupt;
424 } else {
425 dev_info(atc->card->dev, "Use system timer\n");
426 atimer->ops = &ct_systimer_ops;
427 }
428 return atimer;
429}
430
431void ct_timer_free(struct ct_timer *atimer)
432{
433 struct hw *hw = atimer->atc->hw;
434 hw->irq_callback = NULL;
435 if (atimer->ops->free_global)
436 atimer->ops->free_global(atimer);
437 kfree(objp: atimer);
438}
439
440

source code of linux/sound/pci/ctxfi/cttimer.c