/*
* Stop circular DMA descriptor list
* We should not stop DMA in a middle of current transaction once we receive
* stop request from ALSA core. This function finds the next DMA descriptor
* and set it up to decrement DMA channel semaphore. So the current transaction
* is the last data transfer.
*/
static void mxs_pcm_stop(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct mxs_runtime_data *prtd = runtime->private_data;
struct mxs_dma_info dma_info;
int desc;
int periods_num = prtd->dma_totsize / prtd->dma_period;
/* Freez DMA channel for a moment */
mxs_dma_freeze(prtd->dma_ch);
mxs_dma_get_info(prtd->dma_ch, &dma_info);
desc = (dma_info.buf_addr - runtime->dma_addr) / prtd->dma_period;
if (desc >= periods_num)
desc = 0;
else if (desc < 0)
desc = 0;
/* Set up the next descriptor to decrement DMA channel sempahore */
prtd->dma_desc_array[(desc + 1)%periods_num]->cmd.cmd.bits.bytes = 0;
prtd->dma_desc_array[(desc + 1)%periods_num]->cmd.cmd.bits.pio_words = \
0;
prtd->dma_desc_array[(desc + 1)%periods_num]->cmd.cmd.bits.dec_sem = 1;
prtd->dma_desc_array[(desc + 1)%periods_num]->cmd.cmd.bits.irq = 0;
prtd->dma_desc_array[(desc + 1)%periods_num]->cmd.cmd.bits.command = \
NO_DMA_XFER;
mxs_dma_unfreeze(prtd->dma_ch);
mxs_dma_disable(prtd->dma_ch);
}
static irqreturn_t mxs_pcm_dma_irq(int irq, void *dev_id)
{
struct snd_pcm_substream *substream = dev_id;
struct snd_pcm_runtime *runtime = substream->runtime;
struct mxs_runtime_data *prtd = substream->runtime->private_data;
struct mxs_dma_info dma_info;
void *pdma;
unsigned long prev_appl_offset, appl_count, cont, appl_ptr_bytes;
mxs_dma_get_info(prtd->dma_ch, &dma_info);
if (dma_info.status) {
printk(KERN_WARNING "%s: DMA audio channel %d (%s) error\n",
__func__, prtd->params->dma_ch, prtd->params->name);
mxs_dma_ack_irq(prtd->dma_ch);
} else {
if ((prtd->params->dma_ch == MXS_DMA_CHANNEL_AHB_APBX_SPDIF) &&
(substream->stream == SNDRV_PCM_STREAM_PLAYBACK) &&
(runtime->access == SNDRV_PCM_ACCESS_MMAP_INTERLEAVED) &&
((prtd->format == SNDRV_PCM_FORMAT_S24_LE)
|| (prtd->format == SNDRV_PCM_FORMAT_S20_3LE))) {
appl_ptr_bytes =
frames_to_bytes(runtime,
runtime->control->appl_ptr);
appl_count = appl_ptr_bytes - prtd->appl_ptr_bytes;
prev_appl_offset =
prtd->appl_ptr_bytes % prtd->dma_totsize;
cont = prtd->dma_totsize - prev_appl_offset;
if (appl_count > cont) {
pdma = runtime->dma_area + prev_appl_offset;
memmove(pdma + 1, pdma, cont - 1);
pdma = runtime->dma_area;
memmove(pdma + 1, pdma, appl_count - cont - 1);
} else {
pdma = runtime->dma_area + prev_appl_offset;
memmove(pdma + 1, pdma, appl_count - 1);
}
prtd->appl_ptr_bytes = appl_ptr_bytes;
}
mxs_dma_ack_irq(prtd->dma_ch);
snd_pcm_period_elapsed(substream);
}
return IRQ_HANDLED;
}
static snd_pcm_uframes_t
mxs_pcm_pointer(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct mxs_runtime_data *prtd = runtime->private_data;
struct mxs_dma_info dma_info;
unsigned int offset;
dma_addr_t pos;
mxs_dma_get_info(prtd->params->dma_ch, &dma_info);
pos = dma_info.buf_addr;
offset = bytes_to_frames(runtime, pos - runtime->dma_addr);
if (offset >= runtime->buffer_size)
offset = 0;
return offset;
}
