ASoC: core: Add card mutex locking subclasses

This is the first part of a change that is intended to improve
ASoC locking protection for DAPM and PCM operations.

This part of the series adds a mutex class for the soc_card mutex. The
SND_SOC_CARD_CLASS_INIT class is used for card initialisation only whilst the
SND_SOC_CARD_CLASS_PCM class is used for the forth coming Dynamic
PCM operations. The new mutex classes are required otherwise we will see a false
positive mutex deadlock warning between the card initialisation and the PCM
operations (something that would never deadlock in real life).

Signed-off-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

include/sound/soc.h

@@ -288,6 +288,11 @@ enum snd_soc_pcm_subclass {
 	SND_SOC_PCM_CLASS_BE	= 1,
 };
 
+enum snd_soc_card_subclass {
+	SND_SOC_CARD_CLASS_INIT	= 0,
+	SND_SOC_CARD_CLASS_PCM	= 1,
+};
+
 int snd_soc_codec_set_sysclk(struct snd_soc_codec *codec, int clk_id,
 			     int source, unsigned int freq, int dir);
 int snd_soc_codec_set_pll(struct snd_soc_codec *codec, int pll_id, int source,

sound/soc/soc-core.c

@@ -1416,7 +1416,7 @@ static void snd_soc_instantiate_card(struct snd_soc_card *card)
 	struct snd_soc_dai_link *dai_link;
 	int ret, i, order;
 
-	mutex_lock(&card->mutex);
+	mutex_lock_nested(&card->mutex, SND_SOC_CARD_CLASS_INIT);
 
 	if (card->instantiated) {
 		mutex_unlock(&card->mutex);