static int davinci_pcm_prepare(struct snd_pcm_substream *substream)
{
struct davinci_runtime_data *prtd = substream->runtime->private_data;
davinci_pcm_period_reset(substream);
if (prtd->ram_channel >= 0) {
int ret = ping_pong_dma_setup(substream);
if (ret < 0)
return ret;
edma_write_slot(prtd->ram_channel, &prtd->ram_params);
edma_write_slot(prtd->asp_channel, &prtd->asp_params);
print_buf_info(prtd->ram_channel, "ram_channel");
print_buf_info(prtd->ram_link, "ram_link");
print_buf_info(prtd->ram_link2, "ram_link2");
print_buf_info(prtd->asp_channel, "asp_channel");
print_buf_info(prtd->asp_link[0], "asp_link[0]");
print_buf_info(prtd->asp_link[1], "asp_link[1]");
/*
* There is a phase offset of 2 periods between the position
* used by dma setup and the position reported in the pointer
* function.
*
* The phase offset, when not using ping-pong buffers, is due to
* the two consecutive calls to davinci_pcm_enqueue_dma() below.
*
* Whereas here, with ping-pong buffers, the phase is due to
* there being an entire buffer transfer complete before the
* first dma completion event triggers davinci_pcm_dma_irq().
*/
davinci_pcm_period_elapsed(substream);
davinci_pcm_period_elapsed(substream);
return 0;
}
davinci_pcm_enqueue_dma(substream);
davinci_pcm_period_elapsed(substream);
/* Copy self-linked parameter RAM entry into master channel */
edma_read_slot(prtd->asp_link[0], &prtd->asp_params);
edma_write_slot(prtd->asp_channel, &prtd->asp_params);
davinci_pcm_enqueue_dma(substream);
davinci_pcm_period_elapsed(substream);
return 0;
}
static int davinci_pcm_prepare(struct snd_pcm_substream *substream)
{
struct davinci_runtime_data *prtd = substream->runtime->private_data;
if (prtd->ram_channel >= 0) {
int ret = ping_pong_dma_setup(substream);
if (ret < 0)
return ret;
edma_write_slot(prtd->ram_channel, &prtd->ram_params);
edma_write_slot(prtd->asp_channel, &prtd->asp_params);
print_buf_info(prtd->ram_channel, "ram_channel");
print_buf_info(prtd->ram_link, "ram_link");
print_buf_info(prtd->ram_link2, "ram_link2");
print_buf_info(prtd->asp_channel, "asp_channel");
print_buf_info(prtd->asp_link[0], "asp_link[0]");
print_buf_info(prtd->asp_link[1], "asp_link[1]");
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
/* copy 1st iram buffer */
edma_start(prtd->ram_channel);
}
edma_start(prtd->asp_channel);
return 0;
}
prtd->period = 0;
davinci_pcm_enqueue_dma(substream);
/* Copy self-linked parameter RAM entry into master channel */
edma_read_slot(prtd->asp_link[0], &prtd->asp_params);
edma_write_slot(prtd->asp_channel, &prtd->asp_params);
davinci_pcm_enqueue_dma(substream);
edma_start(prtd->asp_channel);
return 0;
}