index 300def59e7b3a6e1db8d8a8700ba57a0b58ef95b..04d4396a1acfb5eda9bd32473a0db26ea3d1ae14 100644 (file)
--- a/pcm.c
+++ b/pcm.c
#include <string.h>
#include <errno.h>
#include <unistd.h>
+#include <poll.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/time.h>
+#include <limits.h>
#include <linux/ioctl.h>
#define __force
#include <tinyalsa/asoundlib.h>
#define PARAM_MAX SNDRV_PCM_HW_PARAM_LAST_INTERVAL
+#define SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP (1<<2)
static inline int param_is_mask(int p)
{
@@ -108,6 +111,16 @@ static void param_set_int(struct snd_pcm_hw_params *p, int n, unsigned int val)
}
}
+static unsigned int param_get_int(struct snd_pcm_hw_params *p, int n)
+{
+ if (param_is_interval(n)) {
+ struct snd_interval *i = param_to_interval(p, n);
+ if (i->integer)
+ return i->max;
+ }
+ return 0;
+}
+
static void param_init(struct snd_pcm_hw_params *p)
{
int n;
int running:1;
int underruns;
unsigned int buffer_size;
+ unsigned int boundary;
char error[PCM_ERROR_MAX];
struct pcm_config config;
struct snd_pcm_mmap_status *mmap_status;
struct snd_pcm_mmap_control *mmap_control;
struct snd_pcm_sync_ptr *sync_ptr;
+ void *mmap_buffer;
+ unsigned int noirq_frames_per_msec;
+ int wait_for_avail_min;
};
unsigned int pcm_get_buffer_size(struct pcm *pcm)
};
}
+unsigned int pcm_bytes_to_frames(struct pcm *pcm, unsigned int bytes)
+{
+ return bytes / (pcm->config.channels *
+ (pcm_format_to_bits(pcm->config.format) >> 3));
+}
+
+unsigned int pcm_frames_to_bytes(struct pcm *pcm, unsigned int frames)
+{
+ return frames * pcm->config.channels *
+ (pcm_format_to_bits(pcm->config.format) >> 3);
+}
+
static int pcm_sync_ptr(struct pcm *pcm, int flags) {
if (pcm->sync_ptr) {
pcm->sync_ptr->flags = flags;
pcm->mmap_status = NULL;
goto mmap_error;
}
- pcm->mmap_control->avail_min = 1;
+ if (pcm->flags & PCM_MMAP)
+ pcm->mmap_control->avail_min = pcm->config.avail_min;
+ else
+ pcm->mmap_control->avail_min = 1;
return 0;
return -ENOMEM;
pcm->mmap_status = &pcm->sync_ptr->s.status;
pcm->mmap_control = &pcm->sync_ptr->c.control;
- pcm->mmap_control->avail_min = 1;
+ if (pcm->flags & PCM_MMAP)
+ pcm->mmap_control->avail_min = pcm->config.avail_min;
+ else
+ pcm->mmap_control->avail_min = 1;
+
pcm_sync_ptr(pcm, 0);
return 0;
pcm->mmap_control = NULL;
}
+static int pcm_areas_copy(struct pcm *pcm, unsigned int pcm_offset,
+ const char *src, unsigned int src_offset,
+ unsigned int frames)
+{
+ int size_bytes = pcm_frames_to_bytes(pcm, frames);
+ int pcm_offset_bytes = pcm_frames_to_bytes(pcm, pcm_offset);
+ int src_offset_bytes = pcm_frames_to_bytes(pcm, src_offset);
+
+ /* interleaved only atm */
+ memcpy((char*)pcm->mmap_buffer + pcm_offset_bytes,
+ src + src_offset_bytes, size_bytes);
+ return 0;
+}
+
+static int pcm_mmap_write_areas(struct pcm *pcm, char *src,
+ unsigned int offset, unsigned int size)
+{
+ void *pcm_areas;
+ int commit;
+ unsigned int pcm_offset, frames, count = 0;
+
+ while (size > 0) {
+ frames = size;
+ pcm_mmap_begin(pcm, &pcm_areas, &pcm_offset, &frames);
+ pcm_areas_copy(pcm, pcm_offset, src, offset, frames);
+ commit = pcm_mmap_commit(pcm, pcm_offset, frames);
+ if (commit < 0) {
+ oops(pcm, commit, "failed to commit %d frames\n", frames);
+ return commit;
+ }
+
+ offset += commit;
+ count += commit;
+ size -= commit;
+ }
+ return count;
+}
+
int pcm_get_htimestamp(struct pcm *pcm, unsigned int *avail,
struct timespec *tstamp)
{
if (rc < 0)
return -1;
+ if ((pcm->mmap_status->state != PCM_STATE_RUNNING) &&
+ (pcm->mmap_status->state != PCM_STATE_DRAINING))
+ return -1;
+
*tstamp = pcm->mmap_status->tstamp;
if (tstamp->tv_sec == 0 && tstamp->tv_nsec == 0)
return -1;
frames = hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr;
if (frames < 0)
- return -1;
+ frames += pcm->boundary;
+ else if (frames > (int)pcm->boundary)
+ frames -= pcm->boundary;
*avail = (unsigned int)frames;
pcm_hw_munmap_status(pcm);
+ if (pcm->flags & PCM_MMAP) {
+ pcm_stop(pcm);
+ munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size));
+ }
+
if (pcm->fd >= 0)
close(pcm->fd);
pcm->running = 0;
if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_INFO, &info)) {
oops(pcm, errno, "cannot get info");
- goto fail;
+ goto fail_close;
}
param_init(¶ms);
- param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_ACCESS,
- SNDRV_PCM_ACCESS_RW_INTERLEAVED);
param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_FORMAT,
pcm_format_to_alsa(config->format));
param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_SUBFORMAT,
param_set_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count);
param_set_int(¶ms, SNDRV_PCM_HW_PARAM_RATE, config->rate);
+ if (flags & PCM_NOIRQ) {
+
+ if (!(flags & PCM_MMAP)) {
+ oops(pcm, -EINVAL, "noirq only currently supported with mmap().");
+ goto fail;
+ }
+
+ params.flags |= SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP;
+ pcm->noirq_frames_per_msec = config->rate / 1000;
+ }
+
+ if (flags & PCM_MMAP)
+ param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_ACCESS,
+ SNDRV_PCM_ACCESS_MMAP_INTERLEAVED);
+ else
+ param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_ACCESS,
+ SNDRV_PCM_ACCESS_RW_INTERLEAVED);
+
if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, ¶ms)) {
oops(pcm, errno, "cannot set hw params");
- goto fail;
+ goto fail_close;
+ }
+
+ /* get our refined hw_params */
+ config->period_size = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
+ config->period_count = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS);
+ pcm->buffer_size = config->period_count * config->period_size;
+
+ if (flags & PCM_MMAP) {
+ pcm->mmap_buffer = mmap(NULL, pcm_frames_to_bytes(pcm, pcm->buffer_size),
+ PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, pcm->fd, 0);
+ if (pcm->mmap_buffer == MAP_FAILED) {
+ oops(pcm, -errno, "failed to mmap buffer %d bytes\n",
+ pcm_frames_to_bytes(pcm, pcm->buffer_size));
+ goto fail_close;
+ }
}
+
memset(&sparams, 0, sizeof(sparams));
sparams.tstamp_mode = SNDRV_PCM_TSTAMP_ENABLE;
sparams.period_step = 1;
- sparams.avail_min = 1;
if (!config->start_threshold)
- sparams.start_threshold = config->period_count * config->period_size;
+ pcm->config.start_threshold = sparams.start_threshold =
+ config->period_count * config->period_size / 2;
else
sparams.start_threshold = config->start_threshold;
+ /* pick a high stop threshold - todo: does this need further tuning */
if (!config->stop_threshold)
- sparams.stop_threshold = config->period_count * config->period_size;
+ pcm->config.stop_threshold = sparams.stop_threshold =
+ config->period_count * config->period_size;
else
sparams.stop_threshold = config->stop_threshold;
+ if (!pcm->config.avail_min) {
+ if (pcm->flags & PCM_MMAP)
+ pcm->config.avail_min = sparams.avail_min = pcm->config.period_size;
+ else
+ pcm->config.avail_min = sparams.avail_min = 1;
+ } else
+ sparams.avail_min = config->avail_min;
+
sparams.xfer_align = config->period_size / 2; /* needed for old kernels */
sparams.silence_size = 0;
sparams.silence_threshold = config->silence_threshold;
+ pcm->boundary = sparams.boundary = pcm->buffer_size;
+ while (pcm->boundary * 2 <= LONG_MAX - pcm->buffer_size)
+ pcm->boundary *= 2;
if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SW_PARAMS, &sparams)) {
oops(pcm, errno, "cannot set sw params");
goto fail;
}
- pcm->buffer_size = config->period_count * config->period_size;
pcm->underruns = 0;
return pcm;
fail:
+ if (flags & PCM_MMAP)
+ munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size));
+fail_close:
close(pcm->fd);
pcm->fd = -1;
return pcm;
{
if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_PREPARE) < 0)
return oops(pcm, errno, "cannot prepare channel");
+
+ if (pcm->flags & PCM_MMAP)
+ pcm_sync_ptr(pcm, 0);
+
if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_START) < 0)
return oops(pcm, errno, "cannot start channel");
+ pcm->running = 1;
return 0;
}
if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_DROP) < 0)
return oops(pcm, errno, "cannot stop channel");
+ pcm->running = 0;
return 0;
}
+static inline int pcm_mmap_playback_avail(struct pcm *pcm)
+{
+ int avail;
+
+ avail = pcm->mmap_status->hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr;
+
+ if (avail < 0)
+ avail += pcm->boundary;
+ else if (avail > (int)pcm->boundary)
+ avail -= pcm->boundary;
+
+ return avail;
+}
+
+static inline int pcm_mmap_capture_avail(struct pcm *pcm)
+{
+ int avail = pcm->mmap_status->hw_ptr - pcm->mmap_control->appl_ptr;
+ if (avail < 0)
+ avail += pcm->boundary;
+ return avail;
+}
+
+static inline int pcm_mmap_avail(struct pcm *pcm)
+{
+ pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_HWSYNC);
+ if (pcm->flags & PCM_IN)
+ return pcm_mmap_capture_avail(pcm);
+ else
+ return pcm_mmap_playback_avail(pcm);
+}
+
+static void pcm_mmap_appl_forward(struct pcm *pcm, int frames)
+{
+ unsigned int appl_ptr = pcm->mmap_control->appl_ptr;
+ appl_ptr += frames;
+
+ /* check for boundary wrap */
+ if (appl_ptr > pcm->boundary)
+ appl_ptr -= pcm->boundary;
+ pcm->mmap_control->appl_ptr = appl_ptr;
+}
+
+int pcm_mmap_begin(struct pcm *pcm, void **areas, unsigned int *offset,
+ unsigned int *frames)
+{
+ unsigned int continuous, copy_frames, avail;
+
+ /* return the mmap buffer */
+ *areas = pcm->mmap_buffer;
+
+ /* and the application offset in frames */
+ *offset = pcm->mmap_control->appl_ptr % pcm->buffer_size;
+
+ avail = pcm_mmap_avail(pcm);
+ if (avail > pcm->buffer_size)
+ avail = pcm->buffer_size;
+ continuous = pcm->buffer_size - *offset;
+
+ /* we can only copy frames if the are availabale and continuos */
+ copy_frames = *frames;
+ if (copy_frames > avail)
+ copy_frames = avail;
+ if (copy_frames > continuous)
+ copy_frames = continuous;
+ *frames = copy_frames;
+
+ return 0;
+}
+
+int pcm_mmap_commit(struct pcm *pcm, unsigned int offset, unsigned int frames)
+{
+ /* update the application pointer in userspace and kernel */
+ pcm_mmap_appl_forward(pcm, frames);
+ pcm_sync_ptr(pcm, 0);
+
+ return frames;
+}
+
+int pcm_avail_update(struct pcm *pcm)
+{
+ pcm_sync_ptr(pcm, 0);
+ return pcm_mmap_avail(pcm);
+}
+
+int pcm_state(struct pcm *pcm)
+{
+ int err = pcm_sync_ptr(pcm, 0);
+ if (err < 0)
+ return err;
+
+ return pcm->mmap_status->state;
+}
+
+int pcm_set_avail_min(struct pcm *pcm, int avail_min)
+{
+ if ((~pcm->flags) & (PCM_MMAP | PCM_NOIRQ))
+ return -ENOSYS;
+
+ pcm->config.avail_min = avail_min;
+ return 0;
+}
+
+int pcm_wait(struct pcm *pcm, int timeout)
+{
+ struct pollfd pfd;
+ unsigned short revents = 0;
+ int err;
+
+ pfd.fd = pcm->fd;
+ pfd.events = POLLOUT | POLLERR | POLLNVAL;
+
+ do {
+ /* let's wait for avail or timeout */
+ err = poll(&pfd, 1, timeout);
+ if (err < 0)
+ return -errno;
+
+ /* timeout ? */
+ if (err == 0)
+ return 0;
+
+ /* have we been interrupted ? */
+ if (errno == -EINTR)
+ continue;
+
+ /* check for any errors */
+ if (pfd.revents & (POLLERR | POLLNVAL)) {
+ switch (pcm_state(pcm)) {
+ case PCM_STATE_XRUN:
+ return -EPIPE;
+ case PCM_STATE_SUSPENDED:
+ return -ESTRPIPE;
+ case PCM_STATE_DISCONNECTED:
+ return -ENODEV;
+ default:
+ return -EIO;
+ }
+ }
+ /* poll again if fd not ready for IO */
+ } while (!(pfd.revents & (POLLIN | POLLOUT)));
+
+ return 1;
+}
+
+int pcm_mmap_write(struct pcm *pcm, void *buffer, unsigned int bytes)
+{
+ int err = 0, frames, avail;
+ unsigned int offset = 0, count;
+
+ if (bytes == 0)
+ return 0;
+
+ count = pcm_bytes_to_frames(pcm, bytes);
+
+ while (count > 0) {
+
+ /* get the available space for writing new frames */
+ avail = pcm_avail_update(pcm);
+ if (avail < 0) {
+ fprintf(stderr, "cannot determine available mmap frames");
+ return err;
+ }
+
+ /* start the audio if we reach the threshold */
+ if (!pcm->running &&
+ (pcm->buffer_size - avail) >= pcm->config.start_threshold) {
+ if (pcm_start(pcm) < 0) {
+ fprintf(stderr, "start error: hw 0x%x app 0x%x avail 0x%x\n",
+ (unsigned int)pcm->mmap_status->hw_ptr,
+ (unsigned int)pcm->mmap_control->appl_ptr,
+ avail);
+ return -errno;
+ }
+ pcm->wait_for_avail_min = 0;
+ }
+
+ /* sleep until we have space to write new frames */
+ if (pcm->running) {
+ /* enable waiting for avail_min threshold when less frames than we have to write
+ * are available. */
+ if (!pcm->wait_for_avail_min && (count > (unsigned int)avail))
+ pcm->wait_for_avail_min = 1;
+
+ if (pcm->wait_for_avail_min && (avail < pcm->config.avail_min)) {
+ int time = -1;
+
+ /* disable waiting for avail_min threshold to allow small amounts of data to be
+ * written without waiting as long as there is enough room in buffer. */
+ pcm->wait_for_avail_min = 0;
+
+ if (pcm->flags & PCM_NOIRQ)
+ time = (pcm->config.avail_min - avail) / pcm->noirq_frames_per_msec;
+
+ err = pcm_wait(pcm, time);
+ if (err < 0) {
+ pcm->running = 0;
+ oops(pcm, err, "wait error: hw 0x%x app 0x%x avail 0x%x\n",
+ (unsigned int)pcm->mmap_status->hw_ptr,
+ (unsigned int)pcm->mmap_control->appl_ptr,
+ avail);
+ pcm->mmap_control->appl_ptr = 0;
+ return err;
+ }
+ continue;
+ }
+ }
+
+ frames = count;
+ if (frames > avail)
+ frames = avail;
+
+ if (!frames)
+ break;
+
+ /* copy frames from buffer */
+ frames = pcm_mmap_write_areas(pcm, buffer, offset, frames);
+ if (frames < 0) {
+ fprintf(stderr, "write error: hw 0x%x app 0x%x avail 0x%x\n",
+ (unsigned int)pcm->mmap_status->hw_ptr,
+ (unsigned int)pcm->mmap_control->appl_ptr,
+ avail);
+ return frames;
+ }
+
+ offset += frames;
+ count -= frames;
+ }
+
+_end:
+ return 0;
+}