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305 lines
7.9 KiB
C
305 lines
7.9 KiB
C
/*
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* PCM MMAP Plug-In Interface
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* Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>
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*
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Library General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <sys/poll.h>
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#include "../pcm_local.h"
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/*
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* Basic mmap plugin
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*/
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struct mmap_private_data {
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snd_pcm_t *pcm;
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int channel;
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snd_pcm_mmap_control_t *control;
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char *buffer;
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int frag;
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};
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static int poll_playback(snd_pcm_t *pcm)
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{
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int err;
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struct pollfd pfd;
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if (pcm->mode & SND_PCM_OPEN_NONBLOCK)
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return -EAGAIN;
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pfd.fd = pcm->fd[SND_PCM_CHANNEL_PLAYBACK];
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pfd.events = POLLOUT;
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pfd.revents = 0;
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err = poll(&pfd, 1, 1000);
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return err < 0 ? err : 0;
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}
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static int query_playback(struct mmap_private_data *data,
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snd_pcm_mmap_control_t *control,
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int not_use_poll)
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{
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int err;
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switch (control->status.status) {
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case SND_PCM_STATUS_PREPARED:
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err = snd_pcm_channel_go(data->pcm, data->channel);
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if (err < 0)
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return err;
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break;
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case SND_PCM_STATUS_RUNNING:
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if (!not_use_poll) {
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control->status.expblock = control->status.block + 1;
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err = poll_playback(data->pcm);
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if (err < 0)
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return err;
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}
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break;
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case SND_PCM_STATUS_UNDERRUN:
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return -EPIPE;
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default:
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return -EIO;
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}
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return 0;
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}
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static int poll_capture(snd_pcm_t *pcm)
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{
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int err;
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struct pollfd pfd;
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if (pcm->mode & SND_PCM_OPEN_NONBLOCK)
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return -EAGAIN;
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pfd.fd = pcm->fd[SND_PCM_CHANNEL_CAPTURE];
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pfd.events = POLLIN;
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pfd.revents = 0;
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err = poll(&pfd, 1, 1000);
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return err < 0 ? err : 0;
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}
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static int query_capture(struct mmap_private_data *data,
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snd_pcm_mmap_control_t *control,
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int not_use_poll)
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{
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int err;
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switch (control->status.status) {
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case SND_PCM_STATUS_PREPARED:
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err = snd_pcm_channel_go(data->pcm, data->channel);
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if (err < 0)
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return err;
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break;
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case SND_PCM_STATUS_RUNNING:
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if (!not_use_poll) {
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control->status.expblock = control->status.block + 1;
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err = poll_capture(data->pcm);
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if (err < 0)
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return err;
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}
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break;
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case SND_PCM_STATUS_OVERRUN:
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return -EPIPE;
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default:
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return -EIO;
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}
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return 0;
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}
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static int mmap_transfer_src_ptr(snd_pcm_plugin_t *plugin, char **buffer, size_t *size)
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{
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struct mmap_private_data *data;
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snd_pcm_mmap_control_t *control;
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int interleave, err;
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if (plugin == NULL || buffer == NULL || size == NULL)
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return -EINVAL;
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data = (struct mmap_private_data *)snd_pcm_plugin_extra_data(plugin);
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if (data == NULL)
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return -EINVAL;
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control = data->control;
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if (control == NULL)
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return -EINVAL;
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interleave = control->status.voices < 0;
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if (interleave) {
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*buffer = data->buffer + control->fragments[data->frag].addr;
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if (data->channel == SND_PCM_CHANNEL_PLAYBACK) {
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/* wait until the block is not free */
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while (control->fragments[data->frag].data) {
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err = query_playback(data, control, 0);
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if (err < 0)
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return err;
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}
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}
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*size = control->status.frag_size;
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} else {
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*buffer = NULL; /* use another buffer */
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}
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return 0;
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}
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static ssize_t mmap_transfer(snd_pcm_plugin_t *plugin,
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char *src_ptr, size_t src_size,
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char *dst_ptr, size_t dst_size)
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{
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struct mmap_private_data *data;
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snd_pcm_mmap_control_t *control;
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int interleave, voice, err;
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char *addr;
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if (plugin == NULL || dst_ptr == NULL || dst_size <= 0)
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return -EINVAL;
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data = (struct mmap_private_data *)snd_pcm_plugin_extra_data(plugin);
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if (data == NULL)
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return -EINVAL;
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control = data->control;
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if (control == NULL)
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return -EINVAL;
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interleave = control->status.voices < 0;
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if (interleave) {
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if (dst_size != control->status.frag_size)
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return -EINVAL;
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} else {
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if (dst_size != control->status.frag_size * control->status.voices)
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return -EINVAL;
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}
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if (data->channel == SND_PCM_CHANNEL_PLAYBACK) {
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while (control->fragments[data->frag].data) {
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err = query_playback(data, control, 0);
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if (err < 0)
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return err;
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}
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if (interleave) {
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addr = data->buffer + control->fragments[data->frag].addr;
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if (dst_ptr != addr)
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memcpy(addr, dst_ptr, dst_size);
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control->fragments[data->frag++].data = 1;
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data->frag %= control->status.frags;
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} else {
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int frag;
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for (voice = 0; voice < control->status.voices; voice++) {
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frag = data->frag + (voice * (control->status.frags / control->status.voices));
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while (control->fragments[frag].data) {
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err = query_playback(data, control, 1);
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if (err < 0)
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return err;
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}
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addr = data->buffer + control->fragments[frag].addr;
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if (dst_ptr != addr)
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memcpy(addr, dst_ptr, control->status.frag_size);
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control->fragments[frag].data = 1;
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dst_ptr += control->status.frag_size;
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}
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data->frag++;
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data->frag %= control->status.frags;
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}
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return dst_size;
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} else if (data->channel == SND_PCM_CHANNEL_CAPTURE) {
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while (!control->fragments[data->frag].data) {
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err = query_capture(data, control, 0);
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if (err < 0)
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return err;
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}
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if (interleave) {
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addr = data->buffer + control->fragments[data->frag].addr;
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if (dst_ptr != addr)
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memcpy(dst_ptr, addr, dst_size);
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control->fragments[data->frag++].data = 0;
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data->frag %= control->status.frags;
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} else {
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for (voice = 0; voice < control->status.voices; voice++) {
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while (!control->fragments[data->frag].data) {
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err = query_capture(data, control, 1);
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if (err < 0)
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return err;
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}
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addr = data->buffer + control->fragments[data->frag].addr;
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if (dst_ptr != addr)
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memcpy(dst_ptr, addr, control->status.frag_size);
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control->fragments[data->frag++].data = 0;
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data->frag %= control->status.frags;
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dst_ptr += control->status.frag_size;
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}
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}
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return dst_size;
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} else {
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return -EINVAL;
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}
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}
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static int mmap_action(snd_pcm_plugin_t *plugin, snd_pcm_plugin_action_t action)
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{
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struct mmap_private_data *data;
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if (plugin == NULL)
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return -EINVAL;
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data = (struct mmap_private_data *)snd_pcm_plugin_extra_data(plugin);
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if (action == INIT) {
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if (data->control)
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snd_pcm_munmap(data->pcm, data->channel);
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return snd_pcm_mmap(data->pcm, data->channel, &data->control, (void **)&data->buffer);
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} else if (action == PREPARE) {
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data->frag = 0;
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} else if (action == DRAIN && data->channel == SND_PCM_CHANNEL_PLAYBACK) {
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data->frag = 0;
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} else if (action == FLUSH) {
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data->frag = 0;
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}
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return 0; /* silenty ignore other actions */
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}
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static void mmap_free(snd_pcm_plugin_t *plugin, void *private_data)
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{
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struct mmap_private_data *data;
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if (plugin == NULL)
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return;
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data = (struct mmap_private_data *)snd_pcm_plugin_extra_data(plugin);
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if (data->control)
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snd_pcm_munmap(data->pcm, data->channel);
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}
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int snd_pcm_plugin_build_mmap(snd_pcm_t *pcm, int channel, snd_pcm_plugin_t **r_plugin)
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{
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struct mmap_private_data *data;
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snd_pcm_plugin_t *plugin;
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if (r_plugin == NULL)
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return -EINVAL;
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*r_plugin = NULL;
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if (!pcm || channel < 0 || channel > 1)
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return -EINVAL;
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plugin = snd_pcm_plugin_build(channel == SND_PCM_CHANNEL_PLAYBACK ?
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"I/O mmap playback" :
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"I/O mmap capture",
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sizeof(struct mmap_private_data));
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if (plugin == NULL)
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return -ENOMEM;
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data = (struct mmap_private_data *)snd_pcm_plugin_extra_data(plugin);
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data->pcm = pcm;
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data->channel = channel;
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plugin->transfer_src_ptr = mmap_transfer_src_ptr;
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plugin->transfer = mmap_transfer;
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plugin->action = mmap_action;
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plugin->private_free = mmap_free;
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*r_plugin = plugin;
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return 0;
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}
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