ALSA: hda - Introduce get_delay codec PCM ops

Add a new codec PCM ops, get_delay(), to obtain the codec/stream-
specific PCM delay count.  When it's NULL, nothing changes.

This new feature was requested for CA0132, which has significant
delays in the path depending on the running DSP code.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_codec.h

@@ -757,6 +757,9 @@ struct hda_pcm_ops {
 		       struct snd_pcm_substream *substream);
 	int (*cleanup)(struct hda_pcm_stream *info, struct hda_codec *codec,
 		       struct snd_pcm_substream *substream);
+	unsigned int (*get_delay)(struct hda_pcm_stream *info,
+				  struct hda_codec *codec,
+				  struct snd_pcm_substream *substream);
 };
 
 /* PCM information for each substream */

sound/pci/hda/hda_intel.c

@@ -2349,8 +2349,11 @@ static unsigned int azx_get_position(struct azx *chip,
 				     struct azx_dev *azx_dev,
 				     bool with_check)
 {
+	struct snd_pcm_substream *substream = azx_dev->substream;
+	struct azx_pcm *apcm = snd_pcm_substream_chip(substream);
 	unsigned int pos;
-	int stream = azx_dev->substream->stream;
+	int stream = substream->stream;
+	struct hda_pcm_stream *hinfo = apcm->hinfo[stream];
 	int delay = 0;
 
 	switch (chip->position_fix[stream]) {
@@ -2381,7 +2384,7 @@ static unsigned int azx_get_position(struct azx *chip,
 		pos = 0;
 
 	/* calculate runtime delay from LPIB */
-	if (azx_dev->substream->runtime &&
+	if (substream->runtime &&
 	    chip->position_fix[stream] == POS_FIX_POSBUF &&
 	    (chip->driver_caps & AZX_DCAPS_COUNT_LPIB_DELAY)) {
 		unsigned int lpib_pos = azx_sd_readl(azx_dev, SD_LPIB);
@@ -2399,9 +2402,16 @@ static unsigned int azx_get_position(struct azx *chip,
 			delay = 0;
 			chip->driver_caps &= ~AZX_DCAPS_COUNT_LPIB_DELAY;
 		}
-		azx_dev->substream->runtime->delay =
-			bytes_to_frames(azx_dev->substream->runtime, delay);
+		delay = bytes_to_frames(substream->runtime, delay);
 	}
+
+	if (substream->runtime) {
+		if (hinfo->ops.get_delay)
+			delay += hinfo->ops.get_delay(hinfo, apcm->codec,
+						      substream);
+		substream->runtime->delay = delay;
+	}
+
 	trace_azx_get_position(chip, azx_dev, pos, delay);
 	return pos;
 }