/*
* PCM Interface - mmap
* Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include "config.h"
#include <stdio.h>
#include <malloc.h>
#include <string.h>
#include <poll.h>
#include <sys/mman.h>
#ifdef HAVE_SYS_SHM_H
#include <sys/shm.h>
#endif
#include "pcm_local.h"
void snd_pcm_mmap_appl_backward(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
{
snd_pcm_sframes_t appl_ptr = *pcm->appl.ptr;
appl_ptr -= frames;
if (appl_ptr < 0)
appl_ptr += pcm->boundary;
*pcm->appl.ptr = appl_ptr;
}
void snd_pcm_mmap_appl_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
{
snd_pcm_uframes_t appl_ptr = *pcm->appl.ptr;
appl_ptr += frames;
if (appl_ptr >= pcm->boundary)
appl_ptr -= pcm->boundary;
*pcm->appl.ptr = appl_ptr;
}
void snd_pcm_mmap_hw_backward(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
{
snd_pcm_sframes_t hw_ptr = *pcm->hw.ptr;
hw_ptr -= frames;
if (hw_ptr < 0)
hw_ptr += pcm->boundary;
*pcm->hw.ptr = hw_ptr;
}
void snd_pcm_mmap_hw_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
{
snd_pcm_uframes_t hw_ptr = *pcm->hw.ptr;
hw_ptr += frames;
if (hw_ptr >= pcm->boundary)
hw_ptr -= pcm->boundary;
*pcm->hw.ptr = hw_ptr;
}
static snd_pcm_sframes_t snd_pcm_mmap_write_areas(snd_pcm_t *pcm,
const snd_pcm_channel_area_t *areas,
snd_pcm_uframes_t offset,
snd_pcm_uframes_t size)
{
snd_pcm_uframes_t xfer = 0;
if (snd_pcm_mmap_playback_avail(pcm) < size) {
SNDMSG("too short avail %ld to size %ld", snd_pcm_mmap_playback_avail(pcm), size);
return -EPIPE;
}
while (size > 0) {
const snd_pcm_channel_area_t *pcm_areas;
snd_pcm_uframes_t pcm_offset;
snd_pcm_uframes_t frames = size;
snd_pcm_sframes_t result;
__snd_pcm_mmap_begin(pcm, &pcm_areas, &pcm_offset, &frames);
snd_pcm_areas_copy(pcm_areas, pcm_offset,
areas, offset,
pcm->channels,
frames, pcm->format);
result = __snd_pcm_mmap_commit(pcm, pcm_offset, frames);
if (result < 0)
return xfer > 0 ? (snd_pcm_sframes_t)xfer : result;
offset += result;
xfer += result;
size -= result;
}
return (snd_pcm_sframes_t)xfer;
}
static snd_pcm_sframes_t snd_pcm_mmap_read_areas(snd_pcm_t *pcm,
const snd_pcm_channel_area_t *areas,
snd_pcm_uframes_t offset,
snd_pcm_uframes_t size)
{
snd_pcm_uframes_t xfer = 0;
if (snd_pcm_mmap_capture_avail(pcm) < size) {
SNDMSG("too short avail %ld to size %ld", snd_pcm_mmap_capture_avail(pcm), size);
return -EPIPE;
}
while (size > 0) {
const snd_pcm_channel_area_t *pcm_areas;
snd_pcm_uframes_t pcm_offset;
snd_pcm_uframes_t frames = size;
snd_pcm_sframes_t result;
__snd_pcm_mmap_begin(pcm, &pcm_areas, &pcm_offset, &frames);
snd_pcm_areas_copy(areas, offset,
pcm_areas, pcm_offset,
pcm->channels,
frames, pcm->format);
result = __snd_pcm_mmap_commit(pcm, pcm_offset, frames);
if (result < 0)
return xfer > 0 ? (snd_pcm_sframes_t)xfer : result;
offset += result;
xfer += result;
size -= result;
}
return (snd_pcm_sframes_t)xfer;
}
/**
* \brief Write interleaved frames to a PCM using direct buffer (mmap)
* \param pcm PCM handle
* \param buffer frames containing buffer
* \param size frames to be written
* \return a positive number of frames actually written otherwise a
* negative error code
* \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_PREPARED or #SND_PCM_STATE_RUNNING)
* \retval -EPIPE an underrun occurred
* \retval -ESTRPIPE a suspend event occurred (stream is suspended and waiting for an application recovery)
*
* If the blocking behaviour is selected, then routine waits until
* all requested bytes are played or put to the playback ring buffer.
* The count of bytes can be less only if a signal or underrun occurred.
*
* If the non-blocking behaviour is selected, then routine doesn't wait at all.
*/
snd_pcm_sframes_t snd_pcm_mmap_writei(snd_pcm_t *pcm, const void *buffer, snd_pcm_uframes_t size)
{
snd_pcm_channel_area_t areas[pcm->channels];
snd_pcm_areas_from_buf(pcm, areas, (void*)buffer);
return snd_pcm_write_areas(pcm, areas, 0, size,
snd_pcm_mmap_write_areas);
}
/**
* \brief Write non interleaved frames to a PCM using direct buffer (mmap)
* \param pcm PCM handle
* \param bufs frames containing buffers (one for each channel)
* \param size frames to be written
* \return a positive number of frames actually written otherwise a
* negative error code
* \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_PREPARED or #SND_PCM_STATE_RUNNING)
* \retval -EPIPE an underrun occurred
* \retval -ESTRPIPE a suspend event occurred (stream is suspended and waiting for an application recovery)
*
* If the blocking behaviour is selected, then routine waits until
* all requested bytes are played or put to the playback ring buffer.
* The count of bytes can be less only if a signal or underrun occurred.
*
* If the non-blocking behaviour is selected, then routine doesn't wait at all.
*/
snd_pcm_sframes_t snd_pcm_mmap_writen(snd_pcm_t *pcm, void **bufs, snd_pcm_uframes_t size)
{
snd_pcm_channel_area_t areas[pcm->channels];
snd_pcm_areas_from_bufs(pcm, areas, bufs);
return snd_pcm_write_areas(pcm, areas, 0, size,
snd_pcm_mmap_write_areas);
}
/**
* \brief Read interleaved frames from a PCM using direct buffer (mmap)
* \param pcm PCM handle
* \param buffer frames containing buffer
* \param size frames to be written
* \return a positive number of frames actually read otherwise a
* negative error code
* \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_PREPARED or #SND_PCM_STATE_RUNNING)
* \retval -EPIPE an overrun occurred
* \retval -ESTRPIPE a suspend event occurred (stream is suspended and waiting for an application recovery)
*
* If the blocking behaviour was selected, then routine waits until
* all requested bytes are filled. The count of bytes can be less only
* if a signal or underrun occurred.
*
* If the non-blocking behaviour is selected, then routine doesn't wait at all.
*/
snd_pcm_sframes_t snd_pcm_mmap_readi(snd_pcm_t *pcm, void *buffer, snd_pcm_uframes_t size)
{
snd_pcm_channel_area_t areas[pcm->channels];
snd_pcm_areas_from_buf(pcm, areas, buffer);
return snd_pcm_read_areas(pcm, areas, 0, size,
snd_pcm_mmap_read_areas);
}
/**
* \brief Read non interleaved frames to a PCM using direct buffer (mmap)
* \param pcm PCM handle
* \param bufs frames containing buffers (one for each channel)
* \param size frames to be written
* \return a positive number of frames actually read otherwise a
* negative error code
* \retval -EBADFD PCM is not in the right state (#SND_PCM_STATE_PREPARED or #SND_PCM_STATE_RUNNING)
* \retval -EPIPE an overrun occurred
* \retval -ESTRPIPE a suspend event occurred (stream is suspended and waiting for an application recovery)
*
* If the blocking behaviour was selected, then routine waits until
* all requested bytes are filled. The count of bytes can be less only
* if a signal or underrun occurred.
*
* If the non-blocking behaviour is selected, then routine doesn't wait at all.
*/
snd_pcm_sframes_t snd_pcm_mmap_readn(snd_pcm_t *pcm, void **bufs, snd_pcm_uframes_t size)
{
snd_pcm_channel_area_t areas[pcm->channels];
snd_pcm_areas_from_bufs(pcm, areas, bufs);
return snd_pcm_read_areas(pcm, areas, 0, size,
snd_pcm_mmap_read_areas);
}
int snd_pcm_channel_info_shm(snd_pcm_t *pcm, snd_pcm_channel_info_t *info, int shmid)
{
switch (pcm->access) {
case SND_PCM_ACCESS_MMAP_INTERLEAVED:
case SND_PCM_ACCESS_RW_INTERLEAVED:
info->first = info->channel * pcm->sample_bits;
info->step = pcm->frame_bits;
break;
case SND_PCM_ACCESS_MMAP_NONINTERLEAVED:
case SND_PCM_ACCESS_RW_NONINTERLEAVED:
info->first = 0;
info->step = pcm->sample_bits;
break;
default:
SNDMSG("invalid access type %d", pcm->access);
return -EINVAL;
}
info->addr = 0;
if (pcm->hw_flags & SND_PCM_HW_PARAMS_EXPORT_BUFFER) {
info->type = SND_PCM_AREA_SHM;
info->u.shm.shmid = shmid;
info->u.shm.area = NULL;
} else
info->type = SND_PCM_AREA_LOCAL;
return 0;
}
int snd_pcm_mmap(snd_pcm_t *pcm)
{
int err;
unsigned int c;
assert(pcm);
if (CHECK_SANITY(! pcm->setup)) {
SNDMSG("PCM not set up");
return -EIO;
}
if (CHECK_SANITY(pcm->mmap_channels || pcm->running_areas)) {
SNDMSG("Already mmapped");
return -EBUSY;
}
if (pcm->ops->mmap)
err = pcm->ops->mmap(pcm);
else
err = -ENOSYS;
if (err < 0)
return err;
if (pcm->mmap_shadow)
return 0;
pcm->mmap_channels = calloc(pcm->channels, sizeof(pcm->mmap_channels[0]));
if (!pcm->mmap_channels)
return -ENOMEM;
pcm->running_areas = calloc(pcm->channels, sizeof(pcm->running_areas[0]));
if (!pcm->running_areas) {
free(pcm->mmap_channels);
pcm->mmap_channels = NULL;
return -ENOMEM;
}
for (c = 0; c < pcm->channels; ++c) {
snd_pcm_channel_info_t *i = &pcm->mmap_channels[c];
i->channel = c;
err = snd_pcm_channel_info(pcm, i);
if (err < 0) {
free(pcm->mmap_channels);
free(pcm->running_areas);
pcm->mmap_channels = NULL;
pcm->running_areas = NULL;
return err;
}
}
for (c = 0; c < pcm->channels; ++c) {
snd_pcm_channel_info_t *i = &pcm->mmap_channels[c];
snd_pcm_channel_area_t *a = &pcm->running_areas[c];
char *ptr;
size_t size;
unsigned int c1;
if (i->addr) {
a->addr = i->addr;
a->first = i->first;
a->step = i->step;
continue;
}
size = i->first + i->step * (pcm->buffer_size - 1) + pcm->sample_bits;
for (c1 = c + 1; c1 < pcm->channels; ++c1) {
snd_pcm_channel_info_t *i1 = &pcm->mmap_channels[c1];
size_t s;
if (i1->type != i->type)
continue;
switch (i1->type) {
case SND_PCM_AREA_MMAP:
if (i1->u.mmap.fd != i->u.mmap.fd ||
i1->u.mmap.offset != i->u.mmap.offset)
continue;
break;
case SND_PCM_AREA_SHM:
if (i1->u.shm.shmid != i->u.shm.shmid)
continue;
break;
case SND_PCM_AREA_LOCAL:
break;
default:
assert(0);
}
s = i1->first + i1->step * (pcm->buffer_size - 1) + pcm->sample_bits;
if (s > size)
size = s;
}
size = (size + 7) / 8;
size = page_align(size);
switch (i->type) {
case SND_PCM_AREA_MMAP:
ptr = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED, i->u.mmap.fd, i->u.mmap.offset);
if (ptr == MAP_FAILED) {
SYSERR("mmap failed");
return -errno;
}
i->addr = ptr;
break;
case SND_PCM_AREA_SHM:
#ifdef HAVE_SYS_SHM_H
if (i->u.shm.shmid < 0) {
int id;
/* FIXME: safer permission? */
id = shmget(IPC_PRIVATE, size, 0666);
if (id < 0) {
SYSERR("shmget failed");
return -errno;
}
i->u.shm.shmid = id;
ptr = shmat(i->u.shm.shmid, 0, 0);
if (ptr == (void *) -1) {
SYSERR("shmat failed");
return -errno;
}
/* automatically remove segment if not used */
if (shmctl(id, IPC_RMID, NULL) < 0){
SYSERR("shmctl mark remove failed");
return -errno;
}
i->u.shm.area = snd_shm_area_create(id, ptr);
if (i->u.shm.area == NULL) {
SYSERR("snd_shm_area_create failed");
return -ENOMEM;
}
if (pcm->access == SND_PCM_ACCESS_MMAP_INTERLEAVED ||
pcm->access == SND_PCM_ACCESS_RW_INTERLEAVED) {
unsigned int c1;
for (c1 = c + 1; c1 < pcm->channels; c1++) {
snd_pcm_channel_info_t *i1 = &pcm->mmap_channels[c1];
if (i1->u.shm.shmid < 0) {
i1->u.shm.shmid = id;
i1->u.shm.area = snd_shm_area_share(i->u.shm.area);
}
}
}
} else {
ptr = shmat(i->u.shm.shmid, 0, 0);
if (ptr == (void*) -1) {
SYSERR("shmat failed");
return -errno;
}
}
i->addr = ptr;
break;
#else
SYSERR("shm support not available");
return -ENOSYS;
#endif
case SND_PCM_AREA_LOCAL:
ptr = malloc(size);
if (ptr == NULL) {
SYSERR("malloc failed");
return -errno;
}
i->addr = ptr;
break;
default:
assert(0);
}
for (c1 = c + 1; c1 < pcm->channels; ++c1) {
snd_pcm_channel_info_t *i1 = &pcm->mmap_channels[c1];
if (i1->type != i->type)
continue;
switch (i1->type) {
case SND_PCM_AREA_MMAP:
if (i1->u.mmap.fd != i->u.mmap.fd ||
i1->u.mmap.offset != i->u.mmap.offset)
continue;
break;
case SND_PCM_AREA_SHM:
if (i1->u.shm.shmid != i->u.shm.shmid)
continue;
/* fall through */
case SND_PCM_AREA_LOCAL:
if (pcm->access != SND_PCM_ACCESS_MMAP_INTERLEAVED &&
pcm->access != SND_PCM_ACCESS_RW_INTERLEAVED)
continue;
break;
default:
assert(0);
}
i1->addr = i->addr;
}
a->addr = i->addr;
a->first = i->first;
a->step = i->step;
}
return 0;
}
int snd_pcm_munmap(snd_pcm_t *pcm)
{
int err;
unsigned int c;
assert(pcm);
if (CHECK_SANITY(! pcm->mmap_channels)) {
SNDMSG("Not mmapped");
return -ENXIO;
}
if (pcm->mmap_shadow) {
if (pcm->ops->munmap)
return pcm->ops->munmap(pcm);
else
return -ENOSYS;
}
for (c = 0; c < pcm->channels; ++c) {
snd_pcm_channel_info_t *i = &pcm->mmap_channels[c];
unsigned int c1;
size_t size = i->first + i->step * (pcm->buffer_size - 1) + pcm->sample_bits;
if (!i->addr)
continue;
for (c1 = c + 1; c1 < pcm->channels; ++c1) {
snd_pcm_channel_info_t *i1 = &pcm->mmap_channels[c1];
size_t s;
if (i1->addr != i->addr)
continue;
i1->addr = NULL;
s = i1->first + i1->step * (pcm->buffer_size - 1) + pcm->sample_bits;
if (s > size)
size = s;
}
size = (size + 7) / 8;
size = page_align(size);
switch (i->type) {
case SND_PCM_AREA_MMAP:
err = munmap(i->addr, size);
if (err < 0) {
SYSERR("mmap failed");
return -errno;
}
errno = 0;
break;
case SND_PCM_AREA_SHM:
#ifdef HAVE_SYS_SHM_H
if (i->u.shm.area) {
snd_shm_area_destroy(i->u.shm.area);
i->u.shm.area = NULL;
if (pcm->access == SND_PCM_ACCESS_MMAP_INTERLEAVED ||
pcm->access == SND_PCM_ACCESS_RW_INTERLEAVED) {
unsigned int c1;
for (c1 = c + 1; c1 < pcm->channels; c1++) {
snd_pcm_channel_info_t *i1 = &pcm->mmap_channels[c1];
if (i1->u.shm.area) {
snd_shm_area_destroy(i1->u.shm.area);
i1->u.shm.area = NULL;
}
}
}
}
break;
#else
SYSERR("shm support not available");
return -ENOSYS;
#endif
case SND_PCM_AREA_LOCAL:
free(i->addr);
break;
default:
assert(0);
}
i->addr = NULL;
}
if (pcm->ops->munmap)
err = pcm->ops->munmap(pcm);
else
err = -ENOSYS;
if (err < 0)
return err;
free(pcm->mmap_channels);
free(pcm->running_areas);
pcm->mmap_channels = NULL;
pcm->running_areas = NULL;
return 0;
}
/* called in pcm lock */
snd_pcm_sframes_t snd_pcm_write_mmap(snd_pcm_t *pcm, snd_pcm_uframes_t offset,
snd_pcm_uframes_t size)
{
snd_pcm_uframes_t xfer = 0;
snd_pcm_sframes_t err = 0;
if (! size)
return 0;
while (xfer < size) {
snd_pcm_uframes_t frames = size - xfer;
snd_pcm_uframes_t cont = pcm->buffer_size - offset;
if (cont < frames)
frames = cont;
switch (pcm->access) {
case SND_PCM_ACCESS_MMAP_INTERLEAVED:
{
const snd_pcm_channel_area_t *a = snd_pcm_mmap_areas(pcm);
const char *buf = snd_pcm_channel_area_addr(a, offset);
snd_pcm_unlock(pcm); /* to avoid deadlock */
err = _snd_pcm_writei(pcm, buf, frames);
snd_pcm_lock(pcm);
if (err >= 0)
frames = err;
break;
}
case SND_PCM_ACCESS_MMAP_NONINTERLEAVED:
{
unsigned int channels = pcm->channels;
unsigned int c;
void *bufs[channels];
const snd_pcm_channel_area_t *areas = snd_pcm_mmap_areas(pcm);
for (c = 0; c < channels; ++c) {
const snd_pcm_channel_area_t *a = &areas[c];
bufs[c] = snd_pcm_channel_area_addr(a, offset);
}
snd_pcm_unlock(pcm); /* to avoid deadlock */
err = _snd_pcm_writen(pcm, bufs, frames);
snd_pcm_lock(pcm);
if (err >= 0)
frames = err;
break;
}
default:
SNDMSG("invalid access type %d", pcm->access);
return -EINVAL;
}
if (err < 0)
break;
xfer += frames;
offset = (offset + frames) % pcm->buffer_size;
}
if (xfer > 0)
return xfer;
return err;
}
/* called in pcm lock */
snd_pcm_sframes_t snd_pcm_read_mmap(snd_pcm_t *pcm, snd_pcm_uframes_t offset,
snd_pcm_uframes_t size)
{
snd_pcm_uframes_t xfer = 0;
snd_pcm_sframes_t err = 0;
if (! size)
return 0;
while (xfer < size) {
snd_pcm_uframes_t frames = size - xfer;
snd_pcm_uframes_t cont = pcm->buffer_size - offset;
if (cont < frames)
frames = cont;
switch (pcm->access) {
case SND_PCM_ACCESS_MMAP_INTERLEAVED:
{
const snd_pcm_channel_area_t *a = snd_pcm_mmap_areas(pcm);
char *buf = snd_pcm_channel_area_addr(a, offset);
snd_pcm_unlock(pcm); /* to avoid deadlock */
err = _snd_pcm_readi(pcm, buf, frames);
snd_pcm_lock(pcm);
if (err >= 0)
frames = err;
break;
}
case SND_PCM_ACCESS_MMAP_NONINTERLEAVED:
{
snd_pcm_uframes_t channels = pcm->channels;
unsigned int c;
void *bufs[channels];
const snd_pcm_channel_area_t *areas = snd_pcm_mmap_areas(pcm);
for (c = 0; c < channels; ++c) {
const snd_pcm_channel_area_t *a = &areas[c];
bufs[c] = snd_pcm_channel_area_addr(a, offset);
}
snd_pcm_unlock(pcm); /* to avoid deadlock */
err = _snd_pcm_readn(pcm->fast_op_arg, bufs, frames);
snd_pcm_lock(pcm);
if (err >= 0)
frames = err;
break;
}
default:
SNDMSG("invalid access type %d", pcm->access);
return -EINVAL;
}
if (err < 0)
break;
xfer += frames;
offset = (offset + frames) % pcm->buffer_size;
}
if (xfer > 0)
return xfer;
return err;
}