linux/sound/pci/ctxfi/cttimer.c
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   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
  18static bool use_system_timer;
  19MODULE_PARM_DESC(use_system_timer, "Force to use system-timer");
  20module_param(use_system_timer, bool, S_IRUGO);
  21
  22struct 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 */
  33struct 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 */
  48struct 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
  66static 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
  94static void ct_systimer_init(struct ct_timer_instance *ti)
  95{
  96        setup_timer(&ti->timer, ct_systimer_callback,
  97                    (unsigned long)ti);
  98}
  99
 100static 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
 113static 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
 123static 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
 131static 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
 148static 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
 159static 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
 169static 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 */
 183static 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 */
 233static 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 */
 249static 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
 267static 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 */
 276static 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
 293static 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
 308static 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
 320static void ct_xfitimer_free_global(struct ct_timer *atimer)
 321{
 322        ct_xfitimer_irq_stop(atimer);
 323}
 324
 325static 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
 337struct ct_timer_instance *
 338ct_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
 361void 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
 369void ct_timer_start(struct ct_timer_instance *ti)
 370{
 371        struct ct_timer *atimer = ti->timer_base;
 372        atimer->ops->start(ti);
 373}
 374
 375void ct_timer_stop(struct ct_timer_instance *ti)
 376{
 377        struct ct_timer *atimer = ti->timer_base;
 378        atimer->ops->stop(ti);
 379}
 380
 381void 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
 400static 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
 409struct 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                dev_info(atc->card->dev, "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                dev_info(atc->card->dev, "Use system timer\n");
 430                atimer->ops = &ct_systimer_ops;
 431        }
 432        return atimer;
 433}
 434
 435void 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