ASoC: DaVinci: pcm, constrain buffer size to multiple of period

The dma setup code assumes that the buffer size is a multiple
of the period size.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/davinci/davinci-pcm.c

@@ -244,6 +244,11 @@ static int davinci_pcm_open(struct snd_pcm_substream *substream)
 	int ret = 0;
 
 	snd_soc_set_runtime_hwparams(substream, &davinci_pcm_hardware);
+	/* ensure that buffer size is a multiple of period size */
+	ret = snd_pcm_hw_constraint_integer(runtime,
+						SNDRV_PCM_HW_PARAM_PERIODS);
+	if (ret < 0)
+		return ret;
 
 	prtd = kzalloc(sizeof(struct davinci_runtime_data), GFP_KERNEL);
 	if (prtd == NULL)