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DEFINITIONS
This source file includes following definitions.
- snd_seq_fifo_new
- snd_seq_fifo_delete
- snd_seq_fifo_clear
- snd_seq_fifo_event_in
- fifo_cell_out
- snd_seq_fifo_cell_out
- snd_seq_fifo_cell_putback
- snd_seq_fifo_poll_wait
- snd_seq_fifo_resize
/*
* ALSA sequencer FIFO
* Copyright (c) 1998 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
*
*/
#include <sound/core.h>
#include <linux/slab.h>
#include "seq_fifo.h"
#include "seq_lock.h"
/* FIFO */
/* create new fifo */
struct snd_seq_fifo *snd_seq_fifo_new(int poolsize)
{
struct snd_seq_fifo *f;
f = kzalloc(sizeof(*f), GFP_KERNEL);
if (f == NULL) {
snd_printd("malloc failed for snd_seq_fifo_new() \n");
return NULL;
}
f->pool = snd_seq_pool_new(poolsize);
if (f->pool == NULL) {
kfree(f);
return NULL;
}
if (snd_seq_pool_init(f->pool) < 0) {
snd_seq_pool_delete(&f->pool);
kfree(f);
return NULL;
}
spin_lock_init(&f->lock);
snd_use_lock_init(&f->use_lock);
init_waitqueue_head(&f->input_sleep);
atomic_set(&f->overflow, 0);
f->head = NULL;
f->tail = NULL;
f->cells = 0;
return f;
}
void snd_seq_fifo_delete(struct snd_seq_fifo **fifo)
{
struct snd_seq_fifo *f;
if (snd_BUG_ON(!fifo))
return;
f = *fifo;
if (snd_BUG_ON(!f))
return;
*fifo = NULL;
snd_seq_fifo_clear(f);
/* wake up clients if any */
if (waitqueue_active(&f->input_sleep))
wake_up(&f->input_sleep);
/* release resources...*/
/*....................*/
if (f->pool) {
snd_seq_pool_done(f->pool);
snd_seq_pool_delete(&f->pool);
}
kfree(f);
}
static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f);
/* clear queue */
void snd_seq_fifo_clear(struct snd_seq_fifo *f)
{
struct snd_seq_event_cell *cell;
unsigned long flags;
/* clear overflow flag */
atomic_set(&f->overflow, 0);
snd_use_lock_sync(&f->use_lock);
spin_lock_irqsave(&f->lock, flags);
/* drain the fifo */
while ((cell = fifo_cell_out(f)) != NULL) {
snd_seq_cell_free(cell);
}
spin_unlock_irqrestore(&f->lock, flags);
}
/* enqueue event to fifo */
int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
struct snd_seq_event *event)
{
struct snd_seq_event_cell *cell;
unsigned long flags;
int err;
if (snd_BUG_ON(!f))
return -EINVAL;
snd_use_lock_use(&f->use_lock);
err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL); /* always non-blocking */
if (err < 0) {
if (err == -ENOMEM)
atomic_inc(&f->overflow);
snd_use_lock_free(&f->use_lock);
return err;
}
/* append new cells to fifo */
spin_lock_irqsave(&f->lock, flags);
if (f->tail != NULL)
f->tail->next = cell;
f->tail = cell;
if (f->head == NULL)
f->head = cell;
f->cells++;
spin_unlock_irqrestore(&f->lock, flags);
/* wakeup client */
if (waitqueue_active(&f->input_sleep))
wake_up(&f->input_sleep);
snd_use_lock_free(&f->use_lock);
return 0; /* success */
}
/* dequeue cell from fifo */
static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f)
{
struct snd_seq_event_cell *cell;
if ((cell = f->head) != NULL) {
f->head = cell->next;
/* reset tail if this was the last element */
if (f->tail == cell)
f->tail = NULL;
cell->next = NULL;
f->cells--;
}
return cell;
}
/* dequeue cell from fifo and copy on user space */
int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
struct snd_seq_event_cell **cellp, int nonblock)
{
struct snd_seq_event_cell *cell;
unsigned long flags;
wait_queue_t wait;
if (snd_BUG_ON(!f))
return -EINVAL;
*cellp = NULL;
init_waitqueue_entry(&wait, current);
spin_lock_irqsave(&f->lock, flags);
while ((cell = fifo_cell_out(f)) == NULL) {
if (nonblock) {
/* non-blocking - return immediately */
spin_unlock_irqrestore(&f->lock, flags);
return -EAGAIN;
}
set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&f->input_sleep, &wait);
spin_unlock_irq(&f->lock);
schedule();
spin_lock_irq(&f->lock);
remove_wait_queue(&f->input_sleep, &wait);
if (signal_pending(current)) {
spin_unlock_irqrestore(&f->lock, flags);
return -ERESTARTSYS;
}
}
spin_unlock_irqrestore(&f->lock, flags);
*cellp = cell;
return 0;
}
void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
struct snd_seq_event_cell *cell)
{
unsigned long flags;
if (cell) {
spin_lock_irqsave(&f->lock, flags);
cell->next = f->head;
f->head = cell;
f->cells++;
spin_unlock_irqrestore(&f->lock, flags);
}
}
/* polling; return non-zero if queue is available */
int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file,
poll_table *wait)
{
poll_wait(file, &f->input_sleep, wait);
return (f->cells > 0);
}
/* change the size of pool; all old events are removed */
int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
{
unsigned long flags;
struct snd_seq_pool *newpool, *oldpool;
struct snd_seq_event_cell *cell, *next, *oldhead;
if (snd_BUG_ON(!f || !f->pool))
return -EINVAL;
/* allocate new pool */
newpool = snd_seq_pool_new(poolsize);
if (newpool == NULL)
return -ENOMEM;
if (snd_seq_pool_init(newpool) < 0) {
snd_seq_pool_delete(&newpool);
return -ENOMEM;
}
spin_lock_irqsave(&f->lock, flags);
/* remember old pool */
oldpool = f->pool;
oldhead = f->head;
/* exchange pools */
f->pool = newpool;
f->head = NULL;
f->tail = NULL;
f->cells = 0;
/* NOTE: overflow flag is not cleared */
spin_unlock_irqrestore(&f->lock, flags);
/* release cells in old pool */
for (cell = oldhead; cell; cell = next) {
next = cell->next;
snd_seq_cell_free(cell);
}
snd_seq_pool_delete(&oldpool);
return 0;
}