ASoC: soc-pcm: Get all BEs along DAPM path

dpcm_end_walk_at_be() stops the graph walk when first BE is found for
the given FE component. In a component model we may want to connect
multiple DAIs from different components. A new flag is introduced in
'snd_soc_card', which when set allows DAI/component chaining. Later
PCM operations can be called for all these listed components for a
valid DAPM path.
Signed-off-by: Sameer Pujar <spujar@nvidia.com>
Link: https://lore.kernel.org/r/1604329814-24779-3-git-send-email-spujar@nvidia.comSigned-off-by: Mark Brown <broonie@kernel.org>

include/sound/soc.h

@@ -1084,6 +1084,7 @@ struct snd_soc_card {
 	unsigned int fully_routed:1;
 	unsigned int disable_route_checks:1;
 	unsigned int probed:1;
+	unsigned int component_chaining:1;
 
 	void *drvdata;
 };

sound/soc/soc-pcm.c

@@ -1259,7 +1259,8 @@ int dpcm_path_get(struct snd_soc_pcm_runtime *fe,
 
 	/* get number of valid DAI paths and their widgets */
 	paths = snd_soc_dapm_dai_get_connected_widgets(cpu_dai, stream, list,
-			dpcm_end_walk_at_be);
+			fe->card->component_chaining ?
+				NULL : dpcm_end_walk_at_be);
 
 	dev_dbg(fe->dev, "ASoC: found %d audio %s paths\n", paths,
 			stream ? "capture" : "playback");