sound/pci/ctxfi/cttimer.c

   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
  15 static bool use_system_timer;
  16 MODULE_PARM_DESC(use_system_timer, "Force to use system-timer");
  17 module_param(use_system_timer, bool, 0444);
  18
  19 struct 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 */
  30 struct 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 */
  45 struct 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
  63 static 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(&ti->timer, jiffies + interval);
  88         spin_unlock_irqrestore(&ti->lock, flags);
  89 }
  90
  91 static void ct_systimer_init(struct ct_timer_instance *ti)
  92 {
  93         timer_setup(&ti->timer, ct_systimer_callback, 0);
  94 }
  95
  96 static 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(&ti->timer,
 104                   jiffies + (runtime->period_size * HZ +
 105                              (runtime->rate - 1)) / runtime->rate);
 106         spin_unlock_irqrestore(&ti->lock, flags);
 107 }
 108
 109 static 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(&ti->timer);
 116         spin_unlock_irqrestore(&ti->lock, flags);
 117 }
 118
 119 static void ct_systimer_prepare(struct ct_timer_instance *ti)
 120 {
 121         ct_systimer_stop(ti);
 122         try_to_del_timer_sync(&ti->timer);
 123 }
 124
 125 #define ct_systimer_free        ct_systimer_prepare
 126
 127 static 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
 144 static 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
 155 static 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
 165 static 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  */
 179 static 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(&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((u64)pos * CT_TIMER_FREQ +
 213                                                  rate - 1, 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, 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 */
 229 static 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(&atimer->list_lock, flags);
 242 }
 243
 244 /* Handle timer-interrupt */
 245 static 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, 1);
 254                 spin_unlock(&atimer->lock);
 255                 if (update)
 256                         ct_xfitimer_check_period(atimer);
 257                 spin_lock(&atimer->lock);
 258         } while (atimer->reprogram);
 259         atimer->irq_handling = 0;
 260         spin_unlock_irqrestore(&atimer->lock, flags);
 261 }
 262
 263 static 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 */
 272 static 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(&atimer->lock, flags);
 281                 return;
 282         }
 283
 284         ct_xfitimer_irq_stop(atimer);
 285         ct_xfitimer_reprogram(atimer, 0);
 286         spin_unlock_irqrestore(&atimer->lock, flags);
 287 }
 288
 289 static 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(&ti->running_list))
 296                 atimer->wc = ct_xfitimer_get_wc(atimer);
 297         ti->running = 1;
 298         ti->need_update = 0;
 299         list_add(&ti->running_list, &atimer->running_head);
 300         spin_unlock_irqrestore(&atimer->lock, flags);
 301         ct_xfitimer_update(atimer);
 302 }
 303
 304 static 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(&ti->running_list);
 311         ti->running = 0;
 312         spin_unlock_irqrestore(&atimer->lock, flags);
 313         ct_xfitimer_update(atimer);
 314 }
 315
 316 static void ct_xfitimer_free_global(struct ct_timer *atimer)
 317 {
 318         ct_xfitimer_irq_stop(atimer);
 319 }
 320
 321 static 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
 333 struct ct_timer_instance *
 334 ct_timer_instance_new(struct ct_timer *atimer, struct ct_atc_pcm *apcm)
 335 {
 336         struct ct_timer_instance *ti;
 337
 338         ti = kzalloc(sizeof(*ti), GFP_KERNEL);
 339         if (!ti)
 340                 return NULL;
 341         spin_lock_init(&ti->lock);
 342         INIT_LIST_HEAD(&ti->instance_list);
 343         INIT_LIST_HEAD(&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(&atimer->list_lock);
 351         list_add(&ti->instance_list, &atimer->instance_head);
 352         spin_unlock_irq(&atimer->list_lock);
 353
 354         return ti;
 355 }
 356
 357 void 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
 365 void ct_timer_start(struct ct_timer_instance *ti)
 366 {
 367         struct ct_timer *atimer = ti->timer_base;
 368         atimer->ops->start(ti);
 369 }
 370
 371 void ct_timer_stop(struct ct_timer_instance *ti)
 372 {
 373         struct ct_timer *atimer = ti->timer_base;
 374         atimer->ops->stop(ti);
 375 }
 376
 377 void 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(&atimer->list_lock);
 386         list_del(&ti->instance_list);
 387         spin_unlock_irq(&atimer->list_lock);
 388
 389         kfree(ti);
 390 }
 391
 392 /*
 393  * timer manager
 394  */
 395
 396 static 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
 405 struct ct_timer *ct_timer_new(struct ct_atc *atc)
 406 {
 407         struct ct_timer *atimer;
 408         struct hw *hw;
 409
 410         atimer = kzalloc(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(&atimer->instance_head);
 416         INIT_LIST_HEAD(&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
 431 void 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(atimer);
 438 }
 439