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seq_queue.c

/*
 *   ALSA sequencer Timing queue handling
 *   Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
 *
 *   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
 *
 * MAJOR CHANGES
 *   Nov. 13, 1999      Takashi Iwai <iwai@ww.uni-erlangen.de>
 *     - Queues are allocated dynamically via ioctl.
 *     - When owner client is deleted, all owned queues are deleted, too.
 *     - Owner of unlocked queue is kept unmodified even if it is
 *     manipulated by other clients.
 *     - Owner field in SET_QUEUE_OWNER ioctl must be identical with the
 *       caller client.  i.e. Changing owner to a third client is not
 *       allowed.
 *
 *  Aug. 30, 2000 Takashi Iwai
 *     - Queues are managed in static array again, but with better way.
 *       The API itself is identical.
 *     - The queue is locked when queue_t pinter is returned via
 *       queueptr().  This pointer *MUST* be released afterward by
 *       queuefree(ptr).
 *     - Addition of experimental sync support.
 */

#include <sound/driver.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <sound/core.h>

#include "seq_memory.h"
#include "seq_queue.h"
#include "seq_clientmgr.h"
#include "seq_fifo.h"
#include "seq_timer.h"
#include "seq_info.h"

/* list of allocated queues */
static queue_t *queue_list[SNDRV_SEQ_MAX_QUEUES];
static spinlock_t queue_list_lock = SPIN_LOCK_UNLOCKED;
/* number of queues allocated */
static int num_queues;

int snd_seq_queue_get_cur_queues(void)
{
      return num_queues;
}

/*----------------------------------------------------------------*/

/* assign queue id and insert to list */
static int queue_list_add(queue_t *q)
{
      int i;
      unsigned long flags;

      spin_lock_irqsave(&queue_list_lock, flags);
      for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
            if (! queue_list[i]) {
                  queue_list[i] = q;
                  q->queue = i;
                  num_queues++;
                  spin_unlock_irqrestore(&queue_list_lock, flags);
                  return i;
            }
      }
      spin_unlock_irqrestore(&queue_list_lock, flags);
      return -1;
}

static queue_t *queue_list_remove(int id, int client)
{
      queue_t *q;
      unsigned long flags;

      spin_lock_irqsave(&queue_list_lock, flags);
      q = queue_list[id];
      if (q) {
            spin_lock(&q->owner_lock);
            if (q->owner == client) {
                  /* found */
                  q->klocked = 1;
                  spin_unlock(&q->owner_lock);
                  queue_list[id] = NULL;
                  num_queues--;
                  spin_unlock_irqrestore(&queue_list_lock, flags);
                  return q;
            }
            spin_unlock(&q->owner_lock);
      }
      spin_unlock_irqrestore(&queue_list_lock, flags);
      return NULL;
}

/*----------------------------------------------------------------*/

/* create new queue (constructor) */
static queue_t *queue_new(int owner, int locked)
{
      queue_t *q;

      q = kcalloc(1, sizeof(*q), GFP_KERNEL);
      if (q == NULL) {
            snd_printd("malloc failed for snd_seq_queue_new()\n");
            return NULL;
      }

      spin_lock_init(&q->owner_lock);
      spin_lock_init(&q->check_lock);
      init_MUTEX(&q->timer_mutex);
      snd_use_lock_init(&q->use_lock);
      q->queue = -1;

      q->tickq = snd_seq_prioq_new();
      q->timeq = snd_seq_prioq_new();
      q->timer = snd_seq_timer_new();
      if (q->tickq == NULL || q->timeq == NULL || q->timer == NULL) {
            snd_seq_prioq_delete(&q->tickq);
            snd_seq_prioq_delete(&q->timeq);
            snd_seq_timer_delete(&q->timer);
            kfree(q);
            return NULL;
      }

      q->owner = owner;
      q->locked = locked;
      q->klocked = 0;

      return q;
}

/* delete queue (destructor) */
static void queue_delete(queue_t *q)
{
      /* stop and release the timer */
      snd_seq_timer_stop(q->timer);
      snd_seq_timer_close(q);
      /* wait until access free */
      snd_use_lock_sync(&q->use_lock);
      /* release resources... */
      snd_seq_prioq_delete(&q->tickq);
      snd_seq_prioq_delete(&q->timeq);
      snd_seq_timer_delete(&q->timer);

      kfree(q);
}


/*----------------------------------------------------------------*/

/* setup queues */
int __init snd_seq_queues_init(void)
{
      /*
      memset(queue_list, 0, sizeof(queue_list));
      num_queues = 0;
      */
      return 0;
}

/* delete all existing queues */
void __exit snd_seq_queues_delete(void)
{
      int i;

      /* clear list */
      for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
            if (queue_list[i])
                  queue_delete(queue_list[i]);
      }
}

/* allocate a new queue -
 * return queue index value or negative value for error
 */
int snd_seq_queue_alloc(int client, int locked, unsigned int info_flags)
{
      queue_t *q;

      q = queue_new(client, locked);
      if (q == NULL)
            return -ENOMEM;
      q->info_flags = info_flags;
      if (queue_list_add(q) < 0) {
            queue_delete(q);
            return -ENOMEM;
      }
      snd_seq_queue_use(q->queue, client, 1); /* use this queue */
      return q->queue;
}

/* delete a queue - queue must be owned by the client */
int snd_seq_queue_delete(int client, int queueid)
{
      queue_t *q;

      if (queueid < 0 || queueid >= SNDRV_SEQ_MAX_QUEUES)
            return -EINVAL;
      q = queue_list_remove(queueid, client);
      if (q == NULL)
            return -EINVAL;
      queue_delete(q);

      return 0;
}


/* return pointer to queue structure for specified id */
queue_t *queueptr(int queueid)
{
      queue_t *q;
      unsigned long flags;

      if (queueid < 0 || queueid >= SNDRV_SEQ_MAX_QUEUES)
            return NULL;
      spin_lock_irqsave(&queue_list_lock, flags);
      q = queue_list[queueid];
      if (q)
            snd_use_lock_use(&q->use_lock);
      spin_unlock_irqrestore(&queue_list_lock, flags);
      return q;
}

/* return the (first) queue matching with the specified name */
queue_t *snd_seq_queue_find_name(char *name)
{
      int i;
      queue_t *q;

      for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
            if ((q = queueptr(i)) != NULL) {
                  if (strncmp(q->name, name, sizeof(q->name)) == 0)
                        return q;
                  queuefree(q);
            }
      }
      return NULL;
}


/* -------------------------------------------------------- */

void snd_seq_check_queue(queue_t *q, int atomic, int hop)
{
      unsigned long flags;
      snd_seq_event_cell_t *cell;

      if (q == NULL)
            return;

      /* make this function non-reentrant */
      spin_lock_irqsave(&q->check_lock, flags);
      if (q->check_blocked) {
            q->check_again = 1;
            spin_unlock_irqrestore(&q->check_lock, flags);
            return;           /* other thread is already checking queues */
      }
      q->check_blocked = 1;
      spin_unlock_irqrestore(&q->check_lock, flags);

      __again:
      /* Process tick queue... */
      while ((cell = snd_seq_prioq_cell_peek(q->tickq)) != NULL) {
            if (snd_seq_compare_tick_time(&q->timer->tick.cur_tick, &cell->event.time.tick)) {
                  cell = snd_seq_prioq_cell_out(q->tickq);
                  if (cell)
                        snd_seq_dispatch_event(cell, atomic, hop);
            } else {
                  /* event remains in the queue */
                  break;
            }
      }


      /* Process time queue... */
      while ((cell = snd_seq_prioq_cell_peek(q->timeq)) != NULL) {
            if (snd_seq_compare_real_time(&q->timer->cur_time, &cell->event.time.time)) {
                  cell = snd_seq_prioq_cell_out(q->timeq);
                  if (cell)
                        snd_seq_dispatch_event(cell, atomic, hop);
            } else {
                  /* event remains in the queue */
                  break;
            }
      }

      /* free lock */
      spin_lock_irqsave(&q->check_lock, flags);
      if (q->check_again) {
            q->check_again = 0;
            spin_unlock_irqrestore(&q->check_lock, flags);
            goto __again;
      }
      q->check_blocked = 0;
      spin_unlock_irqrestore(&q->check_lock, flags);
}


/* enqueue a event to singe queue */
int snd_seq_enqueue_event(snd_seq_event_cell_t *cell, int atomic, int hop)
{
      int dest, err;
      queue_t *q;

      snd_assert(cell != NULL, return -EINVAL);
      dest = cell->event.queue;     /* destination queue */
      q = queueptr(dest);
      if (q == NULL)
            return -EINVAL;
      /* handle relative time stamps, convert them into absolute */
      if ((cell->event.flags & SNDRV_SEQ_TIME_MODE_MASK) == SNDRV_SEQ_TIME_MODE_REL) {
            switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {
            case SNDRV_SEQ_TIME_STAMP_TICK:
                  cell->event.time.tick += q->timer->tick.cur_tick;
                  break;

            case SNDRV_SEQ_TIME_STAMP_REAL:
                  snd_seq_inc_real_time(&cell->event.time.time, &q->timer->cur_time);
                  break;
            }
            cell->event.flags &= ~SNDRV_SEQ_TIME_MODE_MASK;
            cell->event.flags |= SNDRV_SEQ_TIME_MODE_ABS;
      }
      /* enqueue event in the real-time or midi queue */
      switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {
      case SNDRV_SEQ_TIME_STAMP_TICK:
            err = snd_seq_prioq_cell_in(q->tickq, cell);
            break;

      case SNDRV_SEQ_TIME_STAMP_REAL:
      default:
            err = snd_seq_prioq_cell_in(q->timeq, cell);
            break;
      }

      if (err < 0) {
            queuefree(q); /* unlock */
            return err;
      }

      /* trigger dispatching */
      snd_seq_check_queue(q, atomic, hop);

      queuefree(q); /* unlock */

      return 0;
}


/*----------------------------------------------------------------*/

static inline int check_access(queue_t *q, int client)
{
      return (q->owner == client) || (!q->locked && !q->klocked);
}

/* check if the client has permission to modify queue parameters.
 * if it does, lock the queue
 */
static int queue_access_lock(queue_t *q, int client)
{
      unsigned long flags;
      int access_ok;
      
      spin_lock_irqsave(&q->owner_lock, flags);
      access_ok = check_access(q, client);
      if (access_ok)
            q->klocked = 1;
      spin_unlock_irqrestore(&q->owner_lock, flags);
      return access_ok;
}

/* unlock the queue */
static inline void queue_access_unlock(queue_t *q)
{
      unsigned long flags;

      spin_lock_irqsave(&q->owner_lock, flags);
      q->klocked = 0;
      spin_unlock_irqrestore(&q->owner_lock, flags);
}

/* exported - only checking permission */
int snd_seq_queue_check_access(int queueid, int client)
{
      queue_t *q = queueptr(queueid);
      int access_ok;
      unsigned long flags;

      if (! q)
            return 0;
      spin_lock_irqsave(&q->owner_lock, flags);
      access_ok = check_access(q, client);
      spin_unlock_irqrestore(&q->owner_lock, flags);
      queuefree(q);
      return access_ok;
}

/*----------------------------------------------------------------*/

/*
 * change queue's owner and permission
 */
int snd_seq_queue_set_owner(int queueid, int client, int locked)
{
      queue_t *q = queueptr(queueid);

      if (q == NULL)
            return -EINVAL;

      if (! queue_access_lock(q, client)) {
            queuefree(q);
            return -EPERM;
      }

      q->locked = locked ? 1 : 0;
      q->owner = client;
      queue_access_unlock(q);
      queuefree(q);

      return 0;
}


/*----------------------------------------------------------------*/

/* open timer -
 * q->use mutex should be down before calling this function to avoid
 * confliction with snd_seq_queue_use()
 */
int snd_seq_queue_timer_open(int queueid)
{
      int result = 0;
      queue_t *queue;
      seq_timer_t *tmr;

      queue = queueptr(queueid);
      if (queue == NULL)
            return -EINVAL;
      tmr = queue->timer;
      if ((result = snd_seq_timer_open(queue)) < 0) {
            snd_seq_timer_defaults(tmr);
            result = snd_seq_timer_open(queue);
      }
      queuefree(queue);
      return result;
}

/* close timer -
 * q->use mutex should be down before calling this function
 */
int snd_seq_queue_timer_close(int queueid)
{
      queue_t *queue;
      seq_timer_t *tmr;
      int result = 0;

      queue = queueptr(queueid);
      if (queue == NULL)
            return -EINVAL;
      tmr = queue->timer;
      snd_seq_timer_close(queue);
      queuefree(queue);
      return result;
}

/* change queue tempo and ppq */
int snd_seq_queue_timer_set_tempo(int queueid, int client, snd_seq_queue_tempo_t *info)
{
      queue_t *q = queueptr(queueid);
      int result;

      if (q == NULL)
            return -EINVAL;
      if (! queue_access_lock(q, client)) {
            queuefree(q);
            return -EPERM;
      }

      result = snd_seq_timer_set_tempo(q->timer, info->tempo);
      if (result >= 0)
            result = snd_seq_timer_set_ppq(q->timer, info->ppq);
      if (result >= 0 && info->skew_base > 0)
            result = snd_seq_timer_set_skew(q->timer, info->skew_value, info->skew_base);
      queue_access_unlock(q);
      queuefree(q);
      return result;
}


/* use or unuse this queue -
 * if it is the first client, starts the timer.
 * if it is not longer used by any clients, stop the timer.
 */
int snd_seq_queue_use(int queueid, int client, int use)
{
      queue_t *queue;

      queue = queueptr(queueid);
      if (queue == NULL)
            return -EINVAL;
      down(&queue->timer_mutex);
      if (use) {
            if (!test_and_set_bit(client, queue->clients_bitmap))
                  queue->clients++;
      } else {
            if (test_and_clear_bit(client, queue->clients_bitmap))
                  queue->clients--;
      }
      if (queue->clients) {
            if (use && queue->clients == 1)
                  snd_seq_timer_defaults(queue->timer);
            snd_seq_timer_open(queue);
      } else {
            snd_seq_timer_close(queue);
      }
      up(&queue->timer_mutex);
      queuefree(queue);
      return 0;
}

/*
 * check if queue is used by the client
 * return negative value if the queue is invalid.
 * return 0 if not used, 1 if used.
 */
int snd_seq_queue_is_used(int queueid, int client)
{
      queue_t *q;
      int result;

      q = queueptr(queueid);
      if (q == NULL)
            return -EINVAL; /* invalid queue */
      result = test_bit(client, q->clients_bitmap) ? 1 : 0;
      queuefree(q);
      return result;
}


/*----------------------------------------------------------------*/

/* notification that client has left the system -
 * stop the timer on all queues owned by this client
 */
void snd_seq_queue_client_termination(int client)
{
      unsigned long flags;
      int i;
      queue_t *q;

      for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
            if ((q = queueptr(i)) == NULL)
                  continue;
            spin_lock_irqsave(&q->owner_lock, flags);
            if (q->owner == client)
                  q->klocked = 1;
            spin_unlock_irqrestore(&q->owner_lock, flags);
            if (q->owner == client) {
                  if (q->timer->running)
                        snd_seq_timer_stop(q->timer);
                  snd_seq_timer_reset(q->timer);
            }
            queuefree(q);
      }
}

/* final stage notification -
 * remove cells for no longer exist client (for non-owned queue)
 * or delete this queue (for owned queue)
 */
void snd_seq_queue_client_leave(int client)
{
      int i;
      queue_t *q;

      /* delete own queues from queue list */
      for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
            if ((q = queue_list_remove(i, client)) != NULL)
                  queue_delete(q);
      }

      /* remove cells from existing queues -
       * they are not owned by this client
       */
      for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
            if ((q = queueptr(i)) == NULL)
                  continue;
            if (test_bit(client, q->clients_bitmap)) {
                  snd_seq_prioq_leave(q->tickq, client, 0);
                  snd_seq_prioq_leave(q->timeq, client, 0);
                  snd_seq_queue_use(q->queue, client, 0);
            }
            queuefree(q);
      }
}



/*----------------------------------------------------------------*/

/* remove cells from all queues */
void snd_seq_queue_client_leave_cells(int client)
{
      int i;
      queue_t *q;

      for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
            if ((q = queueptr(i)) == NULL)
                  continue;
            snd_seq_prioq_leave(q->tickq, client, 0);
            snd_seq_prioq_leave(q->timeq, client, 0);
            queuefree(q);
      }
}

/* remove cells based on flush criteria */
void snd_seq_queue_remove_cells(int client, snd_seq_remove_events_t *info)
{
      int i;
      queue_t *q;

      for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
            if ((q = queueptr(i)) == NULL)
                  continue;
            if (test_bit(client, q->clients_bitmap) &&
                (! (info->remove_mode & SNDRV_SEQ_REMOVE_DEST) ||
                 q->queue == info->queue)) {
                  snd_seq_prioq_remove_events(q->tickq, client, info);
                  snd_seq_prioq_remove_events(q->timeq, client, info);
            }
            queuefree(q);
      }
}

/*----------------------------------------------------------------*/

/*
 * send events to all subscribed ports
 */
static void queue_broadcast_event(queue_t *q, snd_seq_event_t *ev, int from_timer_port, int atomic, int hop)
{
      snd_seq_event_t sev;

      sev = *ev;
      
      sev.flags = SNDRV_SEQ_TIME_STAMP_TICK|SNDRV_SEQ_TIME_MODE_ABS;
      sev.time.tick = q->timer->tick.cur_tick;
      sev.queue = q->queue;
      sev.data.queue.queue = q->queue;

      if (from_timer_port) {
            /* broadcast events from Timer port */
            sev.source.client = SNDRV_SEQ_CLIENT_SYSTEM;
            sev.source.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
            sev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
            snd_seq_kernel_client_dispatch(SNDRV_SEQ_CLIENT_SYSTEM, &sev, atomic, hop);
      }
}

/*
 * process a received queue-control event.
 * this function is exported for seq_sync.c.
 */
void snd_seq_queue_process_event(queue_t *q, snd_seq_event_t *ev, int from_timer_port, int atomic, int hop)
{
      switch (ev->type) {
      case SNDRV_SEQ_EVENT_START:
            snd_seq_prioq_leave(q->tickq, ev->source.client, 1);
            snd_seq_prioq_leave(q->timeq, ev->source.client, 1);
            if (! snd_seq_timer_start(q->timer))
                  queue_broadcast_event(q, ev, from_timer_port, atomic, hop);
            break;

      case SNDRV_SEQ_EVENT_CONTINUE:
            if (! snd_seq_timer_continue(q->timer))
                  queue_broadcast_event(q, ev, from_timer_port, atomic, hop);
            break;

      case SNDRV_SEQ_EVENT_STOP:
            snd_seq_timer_stop(q->timer);
            queue_broadcast_event(q, ev, from_timer_port, atomic, hop);
            break;

      case SNDRV_SEQ_EVENT_TEMPO:
            snd_seq_timer_set_tempo(q->timer, ev->data.queue.param.value);
            queue_broadcast_event(q, ev, from_timer_port, atomic, hop);
            break;

      case SNDRV_SEQ_EVENT_SETPOS_TICK:
            if (snd_seq_timer_set_position_tick(q->timer, ev->data.queue.param.time.tick) == 0) {
                  queue_broadcast_event(q, ev, from_timer_port, atomic, hop);
            }
            break;

      case SNDRV_SEQ_EVENT_SETPOS_TIME:
            if (snd_seq_timer_set_position_time(q->timer, ev->data.queue.param.time.time) == 0) {
                  queue_broadcast_event(q, ev, from_timer_port, atomic, hop);
            }
            break;
      case SNDRV_SEQ_EVENT_QUEUE_SKEW:
            if (snd_seq_timer_set_skew(q->timer,
                                 ev->data.queue.param.skew.value,
                                 ev->data.queue.param.skew.base) == 0) {
                  queue_broadcast_event(q, ev, from_timer_port, atomic, hop);
            }
            break;
      }
}


/*
 * Queue control via timer control port:
 * this function is exported as a callback of timer port.
 */
int snd_seq_control_queue(snd_seq_event_t *ev, int atomic, int hop)
{
      queue_t *q;

      snd_assert(ev != NULL, return -EINVAL);
      q = queueptr(ev->data.queue.queue);

      if (q == NULL)
            return -EINVAL;

      if (! queue_access_lock(q, ev->source.client)) {
            queuefree(q);
            return -EPERM;
      }

      snd_seq_queue_process_event(q, ev, 1, atomic, hop);

      queue_access_unlock(q);
      queuefree(q);
      return 0;
}


/*----------------------------------------------------------------*/

/* exported to seq_info.c */
void snd_seq_info_queues_read(snd_info_entry_t *entry, 
                        snd_info_buffer_t * buffer)
{
      int i, bpm;
      queue_t *q;
      seq_timer_t *tmr;

      for (i = 0; i < SNDRV_SEQ_MAX_QUEUES; i++) {
            if ((q = queueptr(i)) == NULL)
                  continue;

            tmr = q->timer;
            if (tmr->tempo)
                  bpm = 60000000 / tmr->tempo;
            else
                  bpm = 0;

            snd_iprintf(buffer, "queue %d: [%s]\n", q->queue, q->name);
            snd_iprintf(buffer, "owned by client    : %d\n", q->owner);
            snd_iprintf(buffer, "lock status        : %s\n", q->locked ? "Locked" : "Free");
            snd_iprintf(buffer, "queued time events : %d\n", snd_seq_prioq_avail(q->timeq));
            snd_iprintf(buffer, "queued tick events : %d\n", snd_seq_prioq_avail(q->tickq));
            snd_iprintf(buffer, "timer state        : %s\n", tmr->running ? "Running" : "Stopped");
            snd_iprintf(buffer, "timer PPQ          : %d\n", tmr->ppq);
            snd_iprintf(buffer, "current tempo      : %d\n", tmr->tempo);
            snd_iprintf(buffer, "current BPM        : %d\n", bpm);
            snd_iprintf(buffer, "current time       : %d.%09d s\n", tmr->cur_time.tv_sec, tmr->cur_time.tv_nsec);
            snd_iprintf(buffer, "current tick       : %d\n", tmr->tick.cur_tick);
            snd_iprintf(buffer, "\n");
            queuefree(q);
      }
}

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