ASoC: soc-pcm: dpcm: fix playback/capture checks

Recent changes in the ASoC core prevent multi-cpu BE dailinks from
being used. DPCM does support multi-cpu DAIs for BE Dailinks, but not
for FE.

Handle the FE checks first, and make sure all DAIs support the same
capabilities within the same dailink.

BugLink: #2031
Fixes: 9b5db05 ("ASoC: soc-pcm: dpcm: Only allow playback/capture if supported")
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

Author: plbossart

sound/soc/soc-pcm.c

@@ -2908,20 +2908,42 @@ int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num)
 	struct snd_pcm *pcm;
 	char new_name[64];
 	int ret = 0, playback = 0, capture = 0;
+	int stream;
 	int i;
 
+	if (rtd->dai_link->dynamic && rtd->num_cpus > 1) {
+		dev_err(rtd->dev,
+			"DPCM doesn't support Multi CPU for Front-Ends yet\n");
+		return -EINVAL;
+	}
+
 	if (rtd->dai_link->dynamic || rtd->dai_link->no_pcm) {
-		cpu_dai = asoc_rtd_to_cpu(rtd, 0);
-		if (rtd->num_cpus > 1) {
-			dev_err(rtd->dev,
-				"DPCM doesn't support Multi CPU yet\n");
-			return -EINVAL;
-		}
+		for_each_rtd_cpu_dais(rtd, i, cpu_dai) {
+
+			if (rtd->dai_link->dpcm_playback) {
+				stream = SNDRV_PCM_STREAM_PLAYBACK;
+				if (snd_soc_dai_stream_valid(cpu_dai, stream)) {
+					playback = 1;
+				} else if (playback != 0) {
+					dev_err(rtd->card->dev,
+						"CPU Dai %s does not support playback\n",
+						cpu_dai->name);
+					return -EINVAL;
+				}
+			}
 
-		playback = rtd->dai_link->dpcm_playback &&
-			   snd_soc_dai_stream_valid(cpu_dai, SNDRV_PCM_STREAM_PLAYBACK);
-		capture = rtd->dai_link->dpcm_capture &&
-			  snd_soc_dai_stream_valid(cpu_dai, SNDRV_PCM_STREAM_CAPTURE);
+			if (rtd->dai_link->dpcm_capture) {
+				stream = SNDRV_PCM_STREAM_CAPTURE;
+				if (snd_soc_dai_stream_valid(cpu_dai, stream)) {
+					capture = 1;
+				} else if (capture != 0) {
+					dev_err(rtd->card->dev,
+						"CPU Dai %s does not support capture\n",
+						cpu_dai->name);
+					return -EINVAL;
+				}
+			}
+		}
 	} else {
 		/* Adapt stream for codec2codec links */
 		int cpu_capture = rtd->dai_link->params ?