1 files changed, 299 insertions, 0 deletions
diff --git a/sound/core/seq/seq_fifo.c b/sound/core/seq/seq_fifo.c
new file mode 100644
index 000000000..6a2473270
--- /dev/null
+++ b/sound/core/seq/seq_fifo.c
@@ -0,0 +1,299 @@
+/*
+ *   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 <linux/sched/signal.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)
+		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;
+
+	if (f->pool)
+		snd_seq_pool_mark_closing(f->pool);
+
+	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, NULL); /* always non-blocking */
+	if (err < 0) {
+		if ((err == -ENOMEM) || (err == -EAGAIN))
+			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;
+	cell->next = NULL;
+	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_entry_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;
+		if (!f->tail)
+			f->tail = 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);
+
+	/* close the old pool and wait until all users are gone */
+	snd_seq_pool_mark_closing(oldpool);
+	snd_use_lock_sync(&f->use_lock);
+
+	/* 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;
+}
+
+/* get the number of unused cells safely */
+int snd_seq_fifo_unused_cells(struct snd_seq_fifo *f)
+{
+	unsigned long flags;
+	int cells;
+
+	if (!f)
+		return 0;
+
+	snd_use_lock_use(&f->use_lock);
+	spin_lock_irqsave(&f->lock, flags);
+	cells = snd_seq_unused_cells(f->pool);
+	spin_unlock_irqrestore(&f->lock, flags);
+	snd_use_lock_free(&f->use_lock);
+	return cells;
+}