ASoC: audio-graph: Identify 'no_pcm' DAI links for DPCM

PCM devices are created for FE dai links with 'no-pcm' flag as '0'.
Such DAI links have CPU component which implement either pcm_construct()
or pcm_new() at component or dai level respectively. Based on this,
current patch exposes a helper function to identify such components
and populate 'no_pcm' flag for DPCM DAI link.

This helps to have BE<->BE component links where PCM devices need
not be created for CPU component involved in such links.

Signed-off-by: Sameer Pujar <spujar@nvidia.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/1604329814-24779-5-git-send-email-spujar@nvidia.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
index 1e205629e89a24bab113c9d8cf5773f82be9182e..9b0684173a357099c0a5e1c9ac529967645ce139 100644 (file)
--- a/sound/soc/generic/audio-graph-card.c
+++ b/sound/soc/generic/audio-graph-card.c
@@ -111,6 +111,17 @@ static int graph_get_dai_id(struct device_node *ep)
        return id;
 }
 
+static bool soc_component_is_pcm(struct snd_soc_dai_link_component *dlc)
+{
+       struct snd_soc_dai *dai = snd_soc_find_dai_with_mutex(dlc);
+
+       if (dai && (dai->component->driver->pcm_construct ||
+                   dai->driver->pcm_new))
+               return true;
+
+       return false;
+}
+
 static int asoc_simple_parse_dai(struct device_node *ep,
                                 struct snd_soc_dai_link_component *dlc,
                                 int *is_single_link)
@@ -205,6 +216,7 @@ static int graph_dai_link_of_dpcm(struct asoc_simple_priv *priv,
                                  int dup_codec)
 {
        struct device *dev = simple_priv_to_dev(priv);
+       struct snd_soc_card *card = simple_priv_to_card(priv);
        struct snd_soc_dai_link *dai_link = simple_priv_to_link(priv, li->link);
        struct simple_dai_props *dai_props = simple_priv_to_props(priv, li->link);
        struct device_node *top = dev->of_node;
@@ -259,6 +271,19 @@ static int graph_dai_link_of_dpcm(struct asoc_simple_priv *priv,
                if (ret < 0)
                        goto out_put_node;
 
+               /*
+                * In BE<->BE connections it is not required to create
+                * PCM devices at CPU end of the dai link and thus 'no_pcm'
+                * flag needs to be set. It is useful when there are many
+                * BE components and some of these have to be connected to
+                * form a valid audio path.
+                *
+                * For example: FE <-> BE1 <-> BE2 <-> ... <-> BEn where
+                * there are 'n' BE components in the path.
+                */
+               if (card->component_chaining && !soc_component_is_pcm(cpus))
+                       dai_link->no_pcm = 1;
+
                /* card->num_links includes Codec */
                asoc_simple_canonicalize_cpu(dai_link, is_single_links);
        } else {