+static int fsi_data_pop(struct fsi_priv *fsi)
+{
+ struct snd_pcm_runtime *runtime;
+ struct snd_pcm_substream *substream = NULL;
+ int free;
+ int fifo_fill;
+ int width;
+ u8 *start;
+ int i;
+
+ if (!fsi ||
+ !fsi->substream ||
+ !fsi->substream->runtime)
+ return -EINVAL;
+
+ runtime = fsi->substream->runtime;
+
+ /* FSI FIFO has limit.
+ * So, this driver can not send periods data at a time
+ */
+ if (fsi->byte_offset >=
+ fsi->period_len * (fsi->periods + 1)) {
+
+ substream = fsi->substream;
+ fsi->periods = (fsi->periods + 1) % runtime->periods;
+
+ if (0 == fsi->periods)
+ fsi->byte_offset = 0;
+ }
+
+ /* get 1 channel data width */
+ width = frames_to_bytes(runtime, 1) / fsi->chan;
+
+ /* get free space for alsa */
+ free = (fsi->buffer_len - fsi->byte_offset) / width;
+
+ /* get recv size */
+ fifo_fill = fsi_get_fifo_residue(fsi, 0);
+
+ if (free < fifo_fill)
+ fifo_fill = free;
+
+ start = runtime->dma_area;
+ start += fsi->byte_offset;
+
+ switch (width) {
+ case 2:
+ for (i = 0; i < fifo_fill; i++)
+ *((u16 *)start + i) =
+ (u16)(fsi_reg_read(fsi, DIDT) >> 8);
+ break;
+ case 4:
+ for (i = 0; i < fifo_fill; i++)
+ *((u32 *)start + i) = fsi_reg_read(fsi, DIDT);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ fsi->byte_offset += fifo_fill * width;
+
+ fsi_irq_enable(fsi, 0);
+
+ if (substream)
+ snd_pcm_period_elapsed(substream);
+
+ return 0;
+}
+