ASoC: davinci-mcasp: Set rule constraints if implicit BCLK divider is used

Hello Jyri Sarha,

The patch a75a053f1eef: "ASoC: davinci-mcasp: Set rule constraints if implicit BCLK divider is used" from Mar 20, 2015, leads to the following Smatch warning:

	sound/soc/davinci/davinci-mcasp.c:1152 davinci_mcasp_startup()
	error: buffer overflow 'mcasp->ruledata' 2 <= 2

sound/soc/davinci/davinci-mcasp.c
1138
1139 /*

  1140           * Limit the maximum allowed channels for the first stream:
  1141           * number of serializers for the direction * tdm slots per serializer
  1142           */

1143 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
1144 dir = TX_MODE;
1145 else
1146 dir = RX_MODE;

dir is either 1 or 2.

1147
1148 for (i = 0; i < mcasp->num_serializer; i++) {
1149 if (mcasp->serial_dir[i] == dir)
1150 max_channels++;
1151 }

  1152          mcasp->ruledata[dir].serializers = max_channels;
                       ^^^^^^^^^^^^^

->ruledata[] has only two elements so ->ruledata[2] is beyond the end of the array.

  1153          max_channels *= mcasp->tdm_slots;

regards,
dan carpenter

The serializer direction definitions runs from 1 to 2, which does not suite the purpose. The substream->stream is perfect for the purpose and should have been used from the beginning.

---
 sound/soc/davinci/davinci-mcasp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 76156d18..0b6b1b2 100644
@@ -1149,7 +1149,7 @@ static int davinci_mcasp_startup(struct snd_pcm_substream *substream,
 		if (mcasp->serial_dir[i] == dir)
 			max_channels++;
 	}
-	mcasp->ruledata[dir].serializers = max_channels;
+	mcasp->ruledata[substream->stream].serializers = max_channels;
 	max_channels *= mcasp->tdm_slots;
 	/*
 	 * If the already active stream has less channels than the calculated

@@ -1172,7 +1172,7 @@ static int davinci_mcasp_startup(struct snd_pcm_substream *substream,
 	if (mcasp->bclk_master && mcasp->bclk_div == 0 && mcasp->sysclk_freq) {
 		int ret;
 
-		mcasp->ruledata[dir].mcasp = mcasp;
+		mcasp->ruledata[substream->stream].mcasp = mcasp;
 
 		ret = snd_pcm_hw_rule_add(substream->runtime, 0,
 					  SNDRV_PCM_HW_PARAM_RATE,

1.9.1

Applied, thanks.