ALSA: snd-aloop - add pause support

Signed-off-by: Jaroslav Kysela <perex@perex.cz>

sound/drivers/aloop.c

@@ -77,6 +77,7 @@ struct loopback_cable {
 	/* flags */
 	unsigned int valid;
 	unsigned int running;
+	unsigned int pause;
 };
 
 struct loopback_setup {
@@ -254,7 +255,7 @@ static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct loopback_pcm *dpcm = runtime->private_data;
 	struct loopback_cable *cable = dpcm->cable;
-	int err;
+	int err, stream = 1 << substream->stream;
 
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
@@ -264,7 +265,8 @@ static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 		dpcm->last_jiffies = jiffies;
 		dpcm->pcm_rate_shift = 0;
 		spin_lock(&cable->lock);	
-		cable->running |= (1 << substream->stream);
+		cable->running |= stream;
+		cable->pause &= ~stream;
 		spin_unlock(&cable->lock);
 		loopback_timer_start(dpcm);
 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
@@ -272,12 +274,26 @@ static int loopback_trigger(struct snd_pcm_substream *substream, int cmd)
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
 		spin_lock(&cable->lock);	
-		cable->running &= ~(1 << substream->stream);
+		cable->running &= ~stream;
+		cable->pause &= ~stream;
 		spin_unlock(&cable->lock);
 		loopback_timer_stop(dpcm);
 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 			loopback_active_notify(dpcm);
 		break;
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		spin_lock(&cable->lock);	
+		cable->pause |= stream;
+		spin_unlock(&cable->lock);
+		loopback_timer_stop(dpcm);
+		break;
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		spin_lock(&cable->lock);
+		dpcm->last_jiffies = jiffies;
+		cable->pause &= ~stream;
+		spin_unlock(&cable->lock);
+		loopback_timer_start(dpcm);
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -468,7 +484,7 @@ static unsigned int loopback_pos_update(struct loopback_cable *cable)
 	unsigned int running;
 
 	spin_lock(&cable->lock);	
-	running = cable->running;
+	running = cable->running ^ cable->pause;
 	if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) {
 		delta_play = jiffies - dpcm_play->last_jiffies;
 		dpcm_play->last_jiffies += delta_play;
@@ -532,7 +548,7 @@ static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream)
 static struct snd_pcm_hardware loopback_pcm_hardware =
 {
 	.info =		(SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
-			 SNDRV_PCM_INFO_MMAP_VALID),
+			 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE),
 	.formats =	(SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
 			 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |
 			 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE),
@@ -1060,6 +1076,7 @@ static void print_substream_info(struct snd_info_buffer *buffer,
 	}
 	snd_iprintf(buffer, "  valid: %u\n", cable->valid);
 	snd_iprintf(buffer, "  running: %u\n", cable->running);
+	snd_iprintf(buffer, "  pause: %u\n", cable->pause);
 	print_dpcm_info(buffer, cable->streams[0], "Playback");
 	print_dpcm_info(buffer, cable->streams[1], "Capture");
 }