/* * 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) 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) || (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; 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; }