[linux-block.git] / sound / core / seq / seq_fifo.c

/*
 *   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) {
		pr_debug("ALSA: seq: 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;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* ALSA sequencer FIFO
	3	* Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
	4	*
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	19	*
	20	*/
	21
1da177e4 LT	22	#include <sound/core.h>
	23	#include <linux/slab.h>
	24	#include "seq_fifo.h"
	25	#include "seq_lock.h"
	26
	27
	28	/* FIFO */
	29
	30	/* create new fifo */
c7e0b5bf	31	struct snd_seq_fifo *snd_seq_fifo_new(int poolsize)
1da177e4	32	{
c7e0b5bf	33	struct snd_seq_fifo *f;
1da177e4	34
ecca82b4	35	f = kzalloc(sizeof(*f), GFP_KERNEL);
1da177e4	36	if (f == NULL) {
04cc79a0	37	pr_debug("ALSA: seq: malloc failed for snd_seq_fifo_new() \n");
1da177e4 LT	38	return NULL;
	39	}
	40
	41	f->pool = snd_seq_pool_new(poolsize);
	42	if (f->pool == NULL) {
	43	kfree(f);
	44	return NULL;
	45	}
	46	if (snd_seq_pool_init(f->pool) < 0) {
	47	snd_seq_pool_delete(&f->pool);
	48	kfree(f);
	49	return NULL;
	50	}
	51
	52	spin_lock_init(&f->lock);
	53	snd_use_lock_init(&f->use_lock);
	54	init_waitqueue_head(&f->input_sleep);
	55	atomic_set(&f->overflow, 0);
	56
	57	f->head = NULL;
	58	f->tail = NULL;
	59	f->cells = 0;
	60
	61	return f;
	62	}
	63
c7e0b5bf	64	void snd_seq_fifo_delete(struct snd_seq_fifo **fifo)
1da177e4	65	{
c7e0b5bf	66	struct snd_seq_fifo *f;
1da177e4	67
7eaa943c TI	68	if (snd_BUG_ON(!fifo))
7eaa943c TI	69	return;
1da177e4	70	f = *fifo;
7eaa943c TI	71	if (snd_BUG_ON(!f))
7eaa943c TI	72	return;
1da177e4 LT	73	*fifo = NULL;
	74
	75	snd_seq_fifo_clear(f);
	76
	77	/* wake up clients if any */
	78	if (waitqueue_active(&f->input_sleep))
	79	wake_up(&f->input_sleep);
	80
	81	/* release resources...*/
	82	/..................../
	83
	84	if (f->pool) {
	85	snd_seq_pool_done(f->pool);
	86	snd_seq_pool_delete(&f->pool);
	87	}
	88
	89	kfree(f);
	90	}
	91
c7e0b5bf	92	static struct snd_seq_event_cell fifo_cell_out(struct snd_seq_fifo f);
1da177e4 LT	93
1da177e4 LT	94	/* clear queue */
c7e0b5bf	95	void snd_seq_fifo_clear(struct snd_seq_fifo *f)
1da177e4	96	{
c7e0b5bf	97	struct snd_seq_event_cell *cell;
1da177e4 LT	98	unsigned long flags;
	99
	100	/* clear overflow flag */
	101	atomic_set(&f->overflow, 0);
	102
	103	snd_use_lock_sync(&f->use_lock);
	104	spin_lock_irqsave(&f->lock, flags);
	105	/* drain the fifo */
	106	while ((cell = fifo_cell_out(f)) != NULL) {
	107	snd_seq_cell_free(cell);
	108	}
	109	spin_unlock_irqrestore(&f->lock, flags);
	110	}
	111
	112
	113	/* enqueue event to fifo */
c7e0b5bf TI	114	int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
c7e0b5bf TI	115	struct snd_seq_event *event)
1da177e4	116	{
c7e0b5bf	117	struct snd_seq_event_cell *cell;
1da177e4 LT	118	unsigned long flags;
	119	int err;
	120
7eaa943c TI	121	if (snd_BUG_ON(!f))
7eaa943c TI	122	return -EINVAL;
1da177e4 LT	123
	124	snd_use_lock_use(&f->use_lock);
	125	err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL); /* always non-blocking */
	126	if (err < 0) {
	127	if (err == -ENOMEM)
	128	atomic_inc(&f->overflow);
	129	snd_use_lock_free(&f->use_lock);
	130	return err;
	131	}
	132
	133	/* append new cells to fifo */
	134	spin_lock_irqsave(&f->lock, flags);
	135	if (f->tail != NULL)
	136	f->tail->next = cell;
	137	f->tail = cell;
	138	if (f->head == NULL)
	139	f->head = cell;
	140	f->cells++;
	141	spin_unlock_irqrestore(&f->lock, flags);
	142
	143	/* wakeup client */
	144	if (waitqueue_active(&f->input_sleep))
	145	wake_up(&f->input_sleep);
	146
	147	snd_use_lock_free(&f->use_lock);
	148
	149	return 0; /* success */
	150
	151	}
	152
	153	/* dequeue cell from fifo */
c7e0b5bf	154	static struct snd_seq_event_cell fifo_cell_out(struct snd_seq_fifo f)
1da177e4	155	{
c7e0b5bf	156	struct snd_seq_event_cell *cell;
1da177e4 LT	157
	158	if ((cell = f->head) != NULL) {
	159	f->head = cell->next;
	160
	161	/* reset tail if this was the last element */
	162	if (f->tail == cell)
	163	f->tail = NULL;
	164
	165	cell->next = NULL;
	166	f->cells--;
	167	}
	168
	169	return cell;
	170	}
	171
	172	/* dequeue cell from fifo and copy on user space */
c7e0b5bf TI	173	int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
c7e0b5bf TI	174	struct snd_seq_event_cell **cellp, int nonblock)
1da177e4	175	{
c7e0b5bf	176	struct snd_seq_event_cell *cell;
1da177e4 LT	177	unsigned long flags;
	178	wait_queue_t wait;
	179
7eaa943c TI	180	if (snd_BUG_ON(!f))
7eaa943c TI	181	return -EINVAL;
1da177e4 LT	182
	183	*cellp = NULL;
	184	init_waitqueue_entry(&wait, current);
	185	spin_lock_irqsave(&f->lock, flags);
	186	while ((cell = fifo_cell_out(f)) == NULL) {
	187	if (nonblock) {
	188	/* non-blocking - return immediately */
	189	spin_unlock_irqrestore(&f->lock, flags);
	190	return -EAGAIN;
	191	}
	192	set_current_state(TASK_INTERRUPTIBLE);
	193	add_wait_queue(&f->input_sleep, &wait);
	194	spin_unlock_irq(&f->lock);
	195	schedule();
	196	spin_lock_irq(&f->lock);
	197	remove_wait_queue(&f->input_sleep, &wait);
	198	if (signal_pending(current)) {
	199	spin_unlock_irqrestore(&f->lock, flags);
	200	return -ERESTARTSYS;
	201	}
	202	}
	203	spin_unlock_irqrestore(&f->lock, flags);
	204	*cellp = cell;
	205
	206	return 0;
	207	}
	208
	209
c7e0b5bf TI	210	void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
c7e0b5bf TI	211	struct snd_seq_event_cell *cell)
1da177e4 LT	212	{
	213	unsigned long flags;
	214
	215	if (cell) {
	216	spin_lock_irqsave(&f->lock, flags);
	217	cell->next = f->head;
	218	f->head = cell;
	219	f->cells++;
	220	spin_unlock_irqrestore(&f->lock, flags);
	221	}
	222	}
	223
	224
	225	/* polling; return non-zero if queue is available */
c7e0b5bf TI	226	int snd_seq_fifo_poll_wait(struct snd_seq_fifo f, struct file file,
c7e0b5bf TI	227	poll_table *wait)
1da177e4 LT	228	{
	229	poll_wait(file, &f->input_sleep, wait);
	230	return (f->cells > 0);
	231	}
	232
	233	/* change the size of pool; all old events are removed */
c7e0b5bf	234	int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
1da177e4 LT	235	{
1da177e4 LT	236	unsigned long flags;
c7e0b5bf TI	237	struct snd_seq_pool newpool, oldpool;
c7e0b5bf TI	238	struct snd_seq_event_cell cell, next, *oldhead;
1da177e4	239
7eaa943c TI	240	if (snd_BUG_ON(!f \|\| !f->pool))
7eaa943c TI	241	return -EINVAL;
1da177e4 LT	242
	243	/* allocate new pool */
	244	newpool = snd_seq_pool_new(poolsize);
	245	if (newpool == NULL)
	246	return -ENOMEM;
	247	if (snd_seq_pool_init(newpool) < 0) {
	248	snd_seq_pool_delete(&newpool);
	249	return -ENOMEM;
	250	}
	251
	252	spin_lock_irqsave(&f->lock, flags);
	253	/* remember old pool */
	254	oldpool = f->pool;
	255	oldhead = f->head;
	256	/* exchange pools */
	257	f->pool = newpool;
	258	f->head = NULL;
	259	f->tail = NULL;
	260	f->cells = 0;
	261	/* NOTE: overflow flag is not cleared */
	262	spin_unlock_irqrestore(&f->lock, flags);
	263
	264	/* release cells in old pool */
	265	for (cell = oldhead; cell; cell = next) {
	266	next = cell->next;
	267	snd_seq_cell_free(cell);
	268	}
	269	snd_seq_pool_delete(&oldpool);
	270
	271	return 0;
	272	}