ASoC: TWL4030: Fix for the constraint handling

The original implementation of the constraints were good against sane
applications.
If the opening sequence is:
stream1_open, stream1_hw_params, stream2_open, stream2_hw_params -> the
constraints are set correctly for stream2.

But if the sequence is:
stream1_open, stream2_open, stream2_hw_params, stream1_hw_params -> than stream2
would receive constraint rate = 0, sample_bits = 0, since the stream1 has not
yet called hw_params...

The command to trigger this event:
gst-launch-0.10 alsasrc device=hw:0 ! alsasink device=hw:0 sync=false

This patch does some 'black magic' in order to always set the correct
constraints and sets it only when it is needed for the other stream.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 66 insertions, 19 deletions

diff --git a/sound/soc/codecs/twl4030.c b/sound/soc/codecs/twl4030.c
index 921b205de28a..a1b76d7fd130 100644
--- a/sound/soc/codecs/twl4030.c
+++ b/sound/soc/codecs/twl4030.c
@@ -125,6 +125,11 @@ struct twl4030_priv {
 
         struct snd_pcm_substream *master_substream;
         struct snd_pcm_substream *slave_substream;
+
+        unsigned int configured;
+        unsigned int rate;
+        unsigned int sample_bits;
+        unsigned int channels;
 };
 
 /*
@@ -1220,6 +1225,36 @@ static int twl4030_set_bias_level(struct snd_soc_codec *codec,
         return 0;
 }
 
+static void twl4030_constraints(struct twl4030_priv *twl4030,
+                                struct snd_pcm_substream *mst_substream)
+{
+        struct snd_pcm_substream *slv_substream;
+
+        /* Pick the stream, which need to be constrained */
+        if (mst_substream == twl4030->master_substream)
+                slv_substream = twl4030->slave_substream;
+        else if (mst_substream == twl4030->slave_substream)
+                slv_substream = twl4030->master_substream;
+        else /* This should not happen.. */
+                return;
+
+        /* Set the constraints according to the already configured stream */
+        snd_pcm_hw_constraint_minmax(slv_substream->runtime,
+                                SNDRV_PCM_HW_PARAM_RATE,
+                                twl4030->rate,
+                                twl4030->rate);
+
+        snd_pcm_hw_constraint_minmax(slv_substream->runtime,
+                                SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
+                                twl4030->sample_bits,
+                                twl4030->sample_bits);
+
+        snd_pcm_hw_constraint_minmax(slv_substream->runtime,
+                                SNDRV_PCM_HW_PARAM_CHANNELS,
+                                twl4030->channels,
+                                twl4030->channels);
+}
+
 static int twl4030_startup(struct snd_pcm_substream *substream,
                            struct snd_soc_dai *dai)
 {
@@ -1228,26 +1263,16 @@ static int twl4030_startup(struct snd_pcm_substream *substream,
         struct snd_soc_codec *codec = socdev->card->codec;
         struct twl4030_priv *twl4030 = codec->private_data;
 
-        /* If we already have a playback or capture going then constrain
-         * this substream to match it.
-         */
         if (twl4030->master_substream) {
-                struct snd_pcm_runtime *master_runtime;
-                master_runtime = twl4030->master_substream->runtime;
-
-                snd_pcm_hw_constraint_minmax(substream->runtime,
-                                             SNDRV_PCM_HW_PARAM_RATE,
-                                             master_runtime->rate,
-                                             master_runtime->rate);
-
-                snd_pcm_hw_constraint_minmax(substream->runtime,
-                                             SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
-                                             master_runtime->sample_bits,
-                                             master_runtime->sample_bits);
-
                 twl4030->slave_substream = substream;
-        } else
+                /* The DAI has one configuration for playback and capture, so
+                 * if the DAI has been already configured then constrain this
+                 * substream to match it. */
+                if (twl4030->configured)
+                        twl4030_constraints(twl4030, twl4030->master_substream);
+        } else {
                 twl4030->master_substream = substream;
+        }
 
         return 0;
 }
@@ -1264,6 +1289,13 @@ static void twl4030_shutdown(struct snd_pcm_substream *substream,
                 twl4030->master_substream = twl4030->slave_substream;
 
         twl4030->slave_substream = NULL;
+
+        /* If all streams are closed, or the remaining stream has not yet
+         * been configured than set the DAI as not configured. */
+        if (!twl4030->master_substream)
+                twl4030->configured = 0;
+         else if (!twl4030->master_substream->runtime->channels)
+                twl4030->configured = 0;
 }
 
 static int twl4030_hw_params(struct snd_pcm_substream *substream,
@@ -1276,8 +1308,8 @@ static int twl4030_hw_params(struct snd_pcm_substream *substream,
         struct twl4030_priv *twl4030 = codec->private_data;
         u8 mode, old_mode, format, old_format;
 
-        if (substream == twl4030->slave_substream)
-                /* Ignoring hw_params for slave substream */
+        if (twl4030->configured)
+                /* Ignoring hw_params for already configured DAI */
                 return 0;
 
         /* bit rate */
@@ -1357,6 +1389,21 @@ static int twl4030_hw_params(struct snd_pcm_substream *substream,
                 /* set CODECPDZ afterwards */
                 twl4030_codec_enable(codec, 1);
         }
+
+        /* Store the important parameters for the DAI configuration and set
+         * the DAI as configured */
+        twl4030->configured = 1;
+        twl4030->rate = params_rate(params);
+        twl4030->sample_bits = hw_param_interval(params,
+                                        SNDRV_PCM_HW_PARAM_SAMPLE_BITS)->min;
+        twl4030->channels = params_channels(params);
+
+        /* If both playback and capture streams are open, and one of them
+         * is setting the hw parameters right now (since we are here), set
+         * constraints to the other stream to match the current one. */
+        if (twl4030->slave_substream)
+                twl4030_constraints(twl4030, substream);
+
         return 0;
 }