ASoC: remove trigger delay in Freescale MPC8610 sound driver

Remove the delay from the trigger function in the Freescale MPC8610 sound
driver when capture is started.  This delay was used to ensure that the DMA
controller was active when ALSA call the .pointer function to request a
DMA transfer status.  A better approach is for the .pointer function to detect
that DMA has not started, and return zero instead.  This change eliminates
the need for the delay.

Also add some related code to check for a DMA programming error, and report
XRUN if it occurs.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 2 insertions, 18 deletions

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index 169bca295b78..72823a2b33d6 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -466,28 +466,12 @@ static int fsl_ssi_trigger(struct snd_pcm_substream *substream, int cmd,
         case SNDRV_PCM_TRIGGER_START:
                 clrbits32(&ssi->scr, CCSR_SSI_SCR_SSIEN);
         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
-                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                         setbits32(&ssi->scr,
                                 CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_TE);
-                } else {
-                        long timeout = jiffies + 10;
-
+                else
                         setbits32(&ssi->scr,
                                 CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_RE);
-
-                        /* Wait until the SSI has filled its FIFO. Without this
-                         * delay, ALSA complains about overruns.  When the FIFO
-                         * is full, the DMA controller initiates its first
-                         * transfer.  Until then, however, the DMA's DAR
-                         * register is zero, which translates to an
-                         * out-of-bounds pointer.  This makes ALSA think an
-                         * overrun has occurred.
-                         */
-                        while (!(in_be32(&ssi->sisr) & CCSR_SSI_SISR_RFF0) &&
-                               (jiffies < timeout));
-                        if (!(in_be32(&ssi->sisr) & CCSR_SSI_SISR_RFF0))
-                                return -EIO;
-                }
                 break;
 
         case SNDRV_PCM_TRIGGER_STOP: