/* hw_params callback */
static int snd_bcm2835_pcm_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
int err;
struct snd_pcm_runtime *runtime = substream->runtime;
bcm2835_alsa_stream_t *alsa_stream =
(bcm2835_alsa_stream_t *) runtime->private_data;
audio_info(" .. IN\n");
err = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
if (err < 0) {
audio_error
(" pcm_lib_malloc failed to allocated pages for buffers\n");
return err;
}
err = bcm2835_audio_set_params(alsa_stream, params_channels(params),
params_rate(params),
snd_pcm_format_width(params_format
(params)));
if (err < 0) {
audio_error(" error setting hw params\n");
}
bcm2835_audio_setup(alsa_stream);
audio_info(" .. OUT\n");
return err;
}
/* prepare callback */
static int snd_bcm2835_pcm_prepare(struct snd_pcm_substream *substream)
{
struct bcm2835_chip *chip = snd_pcm_substream_chip(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
struct bcm2835_alsa_stream *alsa_stream = runtime->private_data;
int channels;
int err;
audio_info(" .. IN\n");
if (mutex_lock_interruptible(&chip->audio_mutex))
return -EINTR;
/* notify the vchiq that it should enter spdif passthrough mode by
* setting channels=0 (see
* https://github.com/raspberrypi/linux/issues/528) */
if (chip->spdif_status & IEC958_AES0_NONAUDIO)
channels = 0;
else
channels = alsa_stream->channels;
err = bcm2835_audio_set_params(alsa_stream, channels,
alsa_stream->params_rate,
alsa_stream->pcm_format_width);
if (err < 0) {
audio_error(" error setting hw params\n");
}
bcm2835_audio_setup(alsa_stream);
/* in preparation of the stream, set the controls (volume level) of the stream */
bcm2835_audio_set_ctls(alsa_stream->chip);
memset(&alsa_stream->pcm_indirect, 0, sizeof(alsa_stream->pcm_indirect));
alsa_stream->pcm_indirect.hw_buffer_size =
alsa_stream->pcm_indirect.sw_buffer_size =
snd_pcm_lib_buffer_bytes(substream);
alsa_stream->buffer_size = snd_pcm_lib_buffer_bytes(substream);
alsa_stream->period_size = snd_pcm_lib_period_bytes(substream);
alsa_stream->pos = 0;
audio_debug("buffer_size=%d, period_size=%d pos=%d frame_bits=%d\n",
alsa_stream->buffer_size, alsa_stream->period_size,
alsa_stream->pos, runtime->frame_bits);
mutex_unlock(&chip->audio_mutex);
audio_info(" .. OUT\n");
return 0;
}
