ASoC: Fix DMA channel leak in imx-pcm-dma-mx2 driver.

"snd_imx_pcm_hw_params" callback can be called
several times by the user (i.e. OSS emulation)
leading to a DMA channel leak.

Signed-off-by: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/sound/soc/imx/imx-pcm-dma-mx2.c b/sound/soc/imx/imx-pcm-dma-mx2.c
index 1cf2fe889f6a..7d7fbb5d2a91 100644
--- a/sound/soc/imx/imx-pcm-dma-mx2.c
+++ b/sound/soc/imx/imx-pcm-dma-mx2.c
@@ -88,11 +88,13 @@ static int imx_ssi_dma_alloc(struct snd_pcm_substream *substream,
         iprtd->dma_data.dma_request = dma_params->dma;
 
         /* Try to grab a DMA channel */
-        dma_cap_zero(mask);
-        dma_cap_set(DMA_SLAVE, mask);
-        iprtd->dma_chan = dma_request_channel(mask, filter, iprtd);
-        if (!iprtd->dma_chan)
-                return -EINVAL;
+        if (!iprtd->dma_chan) {
+                dma_cap_zero(mask);
+                dma_cap_set(DMA_SLAVE, mask);
+                iprtd->dma_chan = dma_request_channel(mask, filter, iprtd);
+                if (!iprtd->dma_chan)
+                        return -EINVAL;
+        }
 
         switch (params_format(params)) {
         case SNDRV_PCM_FORMAT_S16_LE: