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seq_timer.c

/*
 *   ALSA sequencer Timer
 *   Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
 *                              Jaroslav Kysela <perex@perex.cz>
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <sound/core.h>
#include <linux/slab.h>
#include "seq_timer.h"
#include "seq_queue.h"
#include "seq_info.h"

/* allowed sequencer timer frequencies, in Hz */
#define MIN_FREQUENCY         10
#define MAX_FREQUENCY         6250
#define DEFAULT_FREQUENCY     1000

#define SKEW_BASE 0x10000     /* 16bit shift */

static void snd_seq_timer_set_tick_resolution(struct snd_seq_timer_tick *tick,
                                    int tempo, int ppq)
{
      if (tempo < 1000000)
            tick->resolution = (tempo * 1000) / ppq;
      else {
            /* might overflow.. */
            unsigned int s;
            s = tempo % ppq;
            s = (s * 1000) / ppq;
            tick->resolution = (tempo / ppq) * 1000;
            tick->resolution += s;
      }
      if (tick->resolution <= 0)
            tick->resolution = 1;
      snd_seq_timer_update_tick(tick, 0);
}

/* create new timer (constructor) */
struct snd_seq_timer *snd_seq_timer_new(void)
{
      struct snd_seq_timer *tmr;
      
      tmr = kzalloc(sizeof(*tmr), GFP_KERNEL);
      if (tmr == NULL) {
            snd_printd("malloc failed for snd_seq_timer_new() \n");
            return NULL;
      }
      spin_lock_init(&tmr->lock);

      /* reset setup to defaults */
      snd_seq_timer_defaults(tmr);
      
      /* reset time */
      snd_seq_timer_reset(tmr);
      
      return tmr;
}

/* delete timer (destructor) */
void snd_seq_timer_delete(struct snd_seq_timer **tmr)
{
      struct snd_seq_timer *t = *tmr;
      *tmr = NULL;

      if (t == NULL) {
            snd_printd("oops: snd_seq_timer_delete() called with NULL timer\n");
            return;
      }
      t->running = 0;

      /* reset time */
      snd_seq_timer_stop(t);
      snd_seq_timer_reset(t);

      kfree(t);
}

void snd_seq_timer_defaults(struct snd_seq_timer * tmr)
{
      /* setup defaults */
      tmr->ppq = 96;          /* 96 PPQ */
      tmr->tempo = 500000;    /* 120 BPM */
      snd_seq_timer_set_tick_resolution(&tmr->tick, tmr->tempo, tmr->ppq);
      tmr->running = 0;

      tmr->type = SNDRV_SEQ_TIMER_ALSA;
      tmr->alsa_id.dev_class = seq_default_timer_class;
      tmr->alsa_id.dev_sclass = seq_default_timer_sclass;
      tmr->alsa_id.card = seq_default_timer_card;
      tmr->alsa_id.device = seq_default_timer_device;
      tmr->alsa_id.subdevice = seq_default_timer_subdevice;
      tmr->preferred_resolution = seq_default_timer_resolution;

      tmr->skew = tmr->skew_base = SKEW_BASE;
}

void snd_seq_timer_reset(struct snd_seq_timer * tmr)
{
      unsigned long flags;

      spin_lock_irqsave(&tmr->lock, flags);

      /* reset time & songposition */
      tmr->cur_time.tv_sec = 0;
      tmr->cur_time.tv_nsec = 0;

      tmr->tick.cur_tick = 0;
      tmr->tick.fraction = 0;

      spin_unlock_irqrestore(&tmr->lock, flags);
}


/* called by timer interrupt routine. the period time since previous invocation is passed */
static void snd_seq_timer_interrupt(struct snd_timer_instance *timeri,
                            unsigned long resolution,
                            unsigned long ticks)
{
      unsigned long flags;
      struct snd_seq_queue *q = timeri->callback_data;
      struct snd_seq_timer *tmr;

      if (q == NULL)
            return;
      tmr = q->timer;
      if (tmr == NULL)
            return;
      if (!tmr->running)
            return;

      resolution *= ticks;
      if (tmr->skew != tmr->skew_base) {
            /* FIXME: assuming skew_base = 0x10000 */
            resolution = (resolution >> 16) * tmr->skew +
                  (((resolution & 0xffff) * tmr->skew) >> 16);
      }

      spin_lock_irqsave(&tmr->lock, flags);

      /* update timer */
      snd_seq_inc_time_nsec(&tmr->cur_time, resolution);

      /* calculate current tick */
      snd_seq_timer_update_tick(&tmr->tick, resolution);

      /* register actual time of this timer update */
      do_gettimeofday(&tmr->last_update);

      spin_unlock_irqrestore(&tmr->lock, flags);

      /* check queues and dispatch events */
      snd_seq_check_queue(q, 1, 0);
}

/* set current tempo */
int snd_seq_timer_set_tempo(struct snd_seq_timer * tmr, int tempo)
{
      unsigned long flags;

      snd_assert(tmr, return -EINVAL);
      if (tempo <= 0)
            return -EINVAL;
      spin_lock_irqsave(&tmr->lock, flags);
      if ((unsigned int)tempo != tmr->tempo) {
            tmr->tempo = tempo;
            snd_seq_timer_set_tick_resolution(&tmr->tick, tmr->tempo, tmr->ppq);
      }
      spin_unlock_irqrestore(&tmr->lock, flags);
      return 0;
}

/* set current ppq */
int snd_seq_timer_set_ppq(struct snd_seq_timer * tmr, int ppq)
{
      unsigned long flags;

      snd_assert(tmr, return -EINVAL);
      if (ppq <= 0)
            return -EINVAL;
      spin_lock_irqsave(&tmr->lock, flags);
      if (tmr->running && (ppq != tmr->ppq)) {
            /* refuse to change ppq on running timers */
            /* because it will upset the song position (ticks) */
            spin_unlock_irqrestore(&tmr->lock, flags);
            snd_printd("seq: cannot change ppq of a running timer\n");
            return -EBUSY;
      }

      tmr->ppq = ppq;
      snd_seq_timer_set_tick_resolution(&tmr->tick, tmr->tempo, tmr->ppq);
      spin_unlock_irqrestore(&tmr->lock, flags);
      return 0;
}

/* set current tick position */
int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr,
                            snd_seq_tick_time_t position)
{
      unsigned long flags;

      snd_assert(tmr, return -EINVAL);

      spin_lock_irqsave(&tmr->lock, flags);
      tmr->tick.cur_tick = position;
      tmr->tick.fraction = 0;
      spin_unlock_irqrestore(&tmr->lock, flags);
      return 0;
}

/* set current real-time position */
int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr,
                            snd_seq_real_time_t position)
{
      unsigned long flags;

      snd_assert(tmr, return -EINVAL);

      snd_seq_sanity_real_time(&position);
      spin_lock_irqsave(&tmr->lock, flags);
      tmr->cur_time = position;
      spin_unlock_irqrestore(&tmr->lock, flags);
      return 0;
}

/* set timer skew */
int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew,
                     unsigned int base)
{
      unsigned long flags;

      snd_assert(tmr, return -EINVAL);

      /* FIXME */
      if (base != SKEW_BASE) {
            snd_printd("invalid skew base 0x%x\n", base);
            return -EINVAL;
      }
      spin_lock_irqsave(&tmr->lock, flags);
      tmr->skew = skew;
      spin_unlock_irqrestore(&tmr->lock, flags);
      return 0;
}

int snd_seq_timer_open(struct snd_seq_queue *q)
{
      struct snd_timer_instance *t;
      struct snd_seq_timer *tmr;
      char str[32];
      int err;

      tmr = q->timer;
      snd_assert(tmr != NULL, return -EINVAL);
      if (tmr->timeri)
            return -EBUSY;
      sprintf(str, "sequencer queue %i", q->queue);
      if (tmr->type != SNDRV_SEQ_TIMER_ALSA)    /* standard ALSA timer */
            return -EINVAL;
      if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
            tmr->alsa_id.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
      err = snd_timer_open(&t, str, &tmr->alsa_id, q->queue);
      if (err < 0 && tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE) {
            if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_GLOBAL ||
                tmr->alsa_id.device != SNDRV_TIMER_GLOBAL_SYSTEM) {
                  struct snd_timer_id tid;
                  memset(&tid, 0, sizeof(tid));
                  tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
                  tid.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
                  tid.card = -1;
                  tid.device = SNDRV_TIMER_GLOBAL_SYSTEM;
                  err = snd_timer_open(&t, str, &tid, q->queue);
            }
            if (err < 0) {
                  snd_printk(KERN_ERR "seq fatal error: cannot create timer (%i)\n", err);
                  return err;
            }
      }
      t->callback = snd_seq_timer_interrupt;
      t->callback_data = q;
      t->flags |= SNDRV_TIMER_IFLG_AUTO;
      tmr->timeri = t;
      return 0;
}

int snd_seq_timer_close(struct snd_seq_queue *q)
{
      struct snd_seq_timer *tmr;
      
      tmr = q->timer;
      snd_assert(tmr != NULL, return -EINVAL);
      if (tmr->timeri) {
            snd_timer_stop(tmr->timeri);
            snd_timer_close(tmr->timeri);
            tmr->timeri = NULL;
      }
      return 0;
}

int snd_seq_timer_stop(struct snd_seq_timer * tmr)
{
      if (! tmr->timeri)
            return -EINVAL;
      if (!tmr->running)
            return 0;
      tmr->running = 0;
      snd_timer_pause(tmr->timeri);
      return 0;
}

static int initialize_timer(struct snd_seq_timer *tmr)
{
      struct snd_timer *t;
      unsigned long freq;

      t = tmr->timeri->timer;
      snd_assert(t, return -EINVAL);

      freq = tmr->preferred_resolution;
      if (!freq)
            freq = DEFAULT_FREQUENCY;
      else if (freq < MIN_FREQUENCY)
            freq = MIN_FREQUENCY;
      else if (freq > MAX_FREQUENCY)
            freq = MAX_FREQUENCY;

      tmr->ticks = 1;
      if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
            unsigned long r = t->hw.resolution;
            if (! r && t->hw.c_resolution)
                  r = t->hw.c_resolution(t);
            if (r) {
                  tmr->ticks = (unsigned int)(1000000000uL / (r * freq));
                  if (! tmr->ticks)
                        tmr->ticks = 1;
            }
      }
      tmr->initialized = 1;
      return 0;
}

int snd_seq_timer_start(struct snd_seq_timer * tmr)
{
      if (! tmr->timeri)
            return -EINVAL;
      if (tmr->running)
            snd_seq_timer_stop(tmr);
      snd_seq_timer_reset(tmr);
      if (initialize_timer(tmr) < 0)
            return -EINVAL;
      snd_timer_start(tmr->timeri, tmr->ticks);
      tmr->running = 1;
      do_gettimeofday(&tmr->last_update);
      return 0;
}

int snd_seq_timer_continue(struct snd_seq_timer * tmr)
{
      if (! tmr->timeri)
            return -EINVAL;
      if (tmr->running)
            return -EBUSY;
      if (! tmr->initialized) {
            snd_seq_timer_reset(tmr);
            if (initialize_timer(tmr) < 0)
                  return -EINVAL;
      }
      snd_timer_start(tmr->timeri, tmr->ticks);
      tmr->running = 1;
      do_gettimeofday(&tmr->last_update);
      return 0;
}

/* return current 'real' time. use timeofday() to get better granularity. */
snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr)
{
      snd_seq_real_time_t cur_time;

      cur_time = tmr->cur_time;
      if (tmr->running) { 
            struct timeval tm;
            int usec;
            do_gettimeofday(&tm);
            usec = (int)(tm.tv_usec - tmr->last_update.tv_usec);
            if (usec < 0) {
                  cur_time.tv_nsec += (1000000 + usec) * 1000;
                  cur_time.tv_sec += tm.tv_sec - tmr->last_update.tv_sec - 1;
            } else {
                  cur_time.tv_nsec += usec * 1000;
                  cur_time.tv_sec += tm.tv_sec - tmr->last_update.tv_sec;
            }
            snd_seq_sanity_real_time(&cur_time);
      }
                
      return cur_time;  
}

/* TODO: use interpolation on tick queue (will only be useful for very
 high PPQ values) */
snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr)
{
      return tmr->tick.cur_tick;
}


#ifdef CONFIG_PROC_FS
/* exported to seq_info.c */
void snd_seq_info_timer_read(struct snd_info_entry *entry,
                       struct snd_info_buffer *buffer)
{
      int idx;
      struct snd_seq_queue *q;
      struct snd_seq_timer *tmr;
      struct snd_timer_instance *ti;
      unsigned long resolution;
      
      for (idx = 0; idx < SNDRV_SEQ_MAX_QUEUES; idx++) {
            q = queueptr(idx);
            if (q == NULL)
                  continue;
            if ((tmr = q->timer) == NULL ||
                (ti = tmr->timeri) == NULL) {
                  queuefree(q);
                  continue;
            }
            snd_iprintf(buffer, "Timer for queue %i : %s\n", q->queue, ti->timer->name);
            resolution = snd_timer_resolution(ti) * tmr->ticks;
            snd_iprintf(buffer, "  Period time : %lu.%09lu\n", resolution / 1000000000, resolution % 1000000000);
            snd_iprintf(buffer, "  Skew : %u / %u\n", tmr->skew, tmr->skew_base);
            queuefree(q);
      }
}
#endif /* CONFIG_PROC_FS */


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