ASoC: pcm: Add delay_blk feature

Add delay_blk() to pcm, platform and DAI ops.
The pcm delay_blk() op collects the audio DSP path
delays from the low-level drivers and sets the
runtime->delay field to their aggregate.

Change-Id: Ib7e10f44ab8ccb46dc2f5825081d0afef662d827
Signed-off-by: Kenneth Westfield <kwestfie@codeaurora.org>

include/sound/pcm.h

@@ -80,6 +80,9 @@ struct snd_pcm_ops {
 			struct timespec *system_ts, struct timespec *audio_ts,
 			struct snd_pcm_audio_tstamp_config *audio_tstamp_config,
 			struct snd_pcm_audio_tstamp_report *audio_tstamp_report);
+	int (*delay_blk)(struct snd_pcm_substream *substream);
+	int (*wall_clock)(struct snd_pcm_substream *substream,
+			  struct timespec *audio_ts);
 	int (*copy)(struct snd_pcm_substream *substream, int channel,
 		    snd_pcm_uframes_t pos,
 		    void __user *buf, snd_pcm_uframes_t count);

include/sound/soc.h

@@ -941,6 +941,16 @@ struct snd_soc_platform_driver {
 	snd_pcm_sframes_t (*delay)(struct snd_pcm_substream *,
 		struct snd_soc_dai *);
 
+	/*
+	 * For platform-caused delay reporting, where the thread blocks waiting
+	 * for the delay amount to be determined.  Defining this will cause the
+	 * ASoC core to skip calling the delay callbacks for all components in
+	 * the runtime.
+	 * Optional.
+	 */
+	snd_pcm_sframes_t (*delay_blk)(struct snd_pcm_substream *,
+		struct snd_soc_dai *);
+
 	/* platform stream pcm ops */
 	const struct snd_pcm_ops *ops;
 

sound/soc/soc-pcm.c

@@ -1167,6 +1167,9 @@ static snd_pcm_uframes_t soc_pcm_pointer(struct snd_pcm_substream *substream)
 	if (platform->driver->ops && platform->driver->ops->pointer)
 		offset = platform->driver->ops->pointer(substream);
 
+	if (platform->driver->delay_blk)
+		return offset;
+
 	if (cpu_dai->driver->ops && cpu_dai->driver->ops->delay)
 		delay += cpu_dai->driver->ops->delay(substream, cpu_dai);
 
@@ -1191,6 +1194,22 @@ static snd_pcm_uframes_t soc_pcm_pointer(struct snd_pcm_substream *substream)
 	return offset;
 }
 
+static int soc_pcm_delay_blk(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_platform *platform = rtd->platform;
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_sframes_t delay = 0;
+
+	if (platform->driver->delay_blk)
+		delay = platform->driver->delay_blk(substream,
+				rtd->codec_dais[0]);
+
+	runtime->delay = delay;
+
+	return 0;
+}
+
 /* connect a FE and BE */
 static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 		struct snd_soc_pcm_runtime *be, int stream)
@@ -2722,6 +2741,7 @@ int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num)
 		rtd->ops.hw_free	= dpcm_fe_dai_hw_free;
 		rtd->ops.close		= dpcm_fe_dai_close;
 		rtd->ops.pointer	= soc_pcm_pointer;
+		rtd->ops.delay_blk	= soc_pcm_delay_blk;
 		rtd->ops.ioctl		= soc_pcm_ioctl;
 		rtd->ops.compat_ioctl   = soc_pcm_compat_ioctl;
 	} else {
@@ -2732,6 +2752,7 @@ int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num)
 		rtd->ops.hw_free	= soc_pcm_hw_free;
 		rtd->ops.close		= soc_pcm_close;
 		rtd->ops.pointer	= soc_pcm_pointer;
+		rtd->ops.delay_blk	= soc_pcm_delay_blk;
 		rtd->ops.ioctl		= soc_pcm_ioctl;
 		rtd->ops.compat_ioctl   = soc_pcm_compat_ioctl;
 	}