[PATCH v3 2/2] ASoC: dpcm: play nice with CODEC<->CODEC links

[PATCH v3 2/2] ASoC: dpcm: play nice with CODEC<->CODEC links

[Piotr Stankiewicz]

Currently in situations where a normal CODEC to CODEC link follows a
DPCM DAI, an error in the following form will be logged:

ASoC: can't get [playback|capture] BE for <widget name>
ASoC: no BE found for <widget name>

This happens because all widgets in a path containing a DPCM DAI will
be passed to dpcm_add_paths, which will try to interpret the CODEC<->CODEC
as if it were a DPCM DAI, in turn causing the error.

This patch aims to resolve the described issue by stopping the DPCM graph
walk, initiated from dpcm_path_get, at the first widget associated with
a DPCM BE.

Signed-off-by: Piotr Stankiewicz <piotrs@opensource.wolfsonmicro.com>
---
 sound/soc/soc-pcm.c |   42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index c2b0aa8..60d702f 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1287,6 +1287,46 @@ static int widget_in_list(struct snd_soc_dapm_widget_list *list,
 	return 0;
 }
 
+static bool dpcm_end_walk_at_be(struct snd_soc_dapm_widget *widget,
+		enum snd_soc_dapm_direction dir)
+{
+	struct snd_soc_card *card = widget->dapm->card;
+	struct snd_soc_pcm_runtime *rtd;
+	int i;
+
+	if (dir == SND_SOC_DAPM_DIR_OUT) {
+		list_for_each_entry(rtd, &card->rtd_list, list) {
+			if (!rtd->dai_link->no_pcm)
+				continue;
+
+			if (rtd->cpu_dai->playback_widget == widget)
+				return true;
+
+			for (i = 0; i < rtd->num_codecs; ++i) {
+				struct snd_soc_dai *dai = rtd->codec_dais[i];
+				if (dai->playback_widget == widget)
+					return true;
+			}
+		}
+	} else { /* SND_SOC_DAPM_DIR_IN */
+		list_for_each_entry(rtd, &card->rtd_list, list) {
+			if (!rtd->dai_link->no_pcm)
+				continue;
+
+			if (rtd->cpu_dai->capture_widget == widget)
+				return true;
+
+			for (i = 0; i < rtd->num_codecs; ++i) {
+				struct snd_soc_dai *dai = rtd->codec_dais[i];
+				if (dai->capture_widget == widget)
+					return true;
+			}
+		}
+	}
+
+	return false;
+}
+
 int dpcm_path_get(struct snd_soc_pcm_runtime *fe,
 	int stream, struct snd_soc_dapm_widget_list **list)
 {
@@ -1295,7 +1335,7 @@ int dpcm_path_get(struct snd_soc_pcm_runtime *fe,
 
 	/* get number of valid DAI paths and their widgets */
 	paths = snd_soc_dapm_dai_get_connected_widgets(cpu_dai, stream, list,
-			NULL);
+			dpcm_end_walk_at_be);
 
 	dev_dbg(fe->dev, "ASoC: found %d audio %s paths\n", paths,
 			stream ? "capture" : "playback");
-- 
1.7.10.4

[PATCH v3 1/2] ASoC: dapm: support user-defined stop condition in dai_get_connected_widgets

[Piotr Stankiewicz]

Certain situations may warrant examining DAPM paths only to a certain
arbitrary point, as opposed to always following them to the end. For
instance, when establishing a connection between a front-end DAI link
and a back-end DAI link in a DPCM path, it does not make sense to walk
the DAPM graph beyond the first widget associated with a back-end link.

This patch introduces a mechanism which lets a user of
dai_get_connected_widgets supply a function which will be called for
every node during the graph walk. When invoked, this function can
execute arbitrary logic to decide whether the walk, given a DAPM widget
and walk direction, should be terminated at that point or continued
as normal.

Signed-off-by: Piotr Stankiewicz <piotrs@opensource.wolfsonmicro.com>
---
 include/sound/soc-dapm.h |    5 +++-
 sound/soc/soc-dapm.c     |   58 +++++++++++++++++++++++++++++++++++-----------
 sound/soc/soc-pcm.c      |    3 ++-
 3 files changed, 51 insertions(+), 15 deletions(-)

diff --git a/include/sound/soc-dapm.h b/include/sound/soc-dapm.h
index 9706946..8eed5c4 100644
--- a/include/sound/soc-dapm.h
+++ b/include/sound/soc-dapm.h
@@ -357,6 +357,7 @@ struct snd_soc_dapm_context;
 struct regulator;
 struct snd_soc_dapm_widget_list;
 struct snd_soc_dapm_update;
+enum snd_soc_dapm_direction;
 
 int dapm_regulator_event(struct snd_soc_dapm_widget *w,
 			 struct snd_kcontrol *kcontrol, int event);
@@ -450,7 +451,9 @@ void dapm_mark_endpoints_dirty(struct snd_soc_card *card);
 
 /* dapm path query */
 int snd_soc_dapm_dai_get_connected_widgets(struct snd_soc_dai *dai, int stream,
-	struct snd_soc_dapm_widget_list **list);
+	struct snd_soc_dapm_widget_list **list,
+	bool (*custom_stop_condition)(struct snd_soc_dapm_widget *,
+				      enum snd_soc_dapm_direction));
 
 struct snd_soc_dapm_context *snd_soc_dapm_kcontrol_dapm(
 	struct snd_kcontrol *kcontrol);
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 801ae1a..a6976d5 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -1073,7 +1073,11 @@ static int dapm_widget_list_create(struct snd_soc_dapm_widget_list **list,
  */
 static __always_inline int is_connected_ep(struct snd_soc_dapm_widget *widget,
 	struct list_head *list, enum snd_soc_dapm_direction dir,
-	int (*fn)(struct snd_soc_dapm_widget *, struct list_head *))
+	int (*fn)(struct snd_soc_dapm_widget *, struct list_head *,
+		  bool (*custom_stop_condition)(struct snd_soc_dapm_widget *,
+						enum snd_soc_dapm_direction)),
+	bool (*custom_stop_condition)(struct snd_soc_dapm_widget *,
+				      enum snd_soc_dapm_direction))
 {
 	enum snd_soc_dapm_direction rdir = SND_SOC_DAPM_DIR_REVERSE(dir);
 	struct snd_soc_dapm_path *path;
@@ -1088,6 +1092,9 @@ static __always_inline int is_connected_ep(struct snd_soc_dapm_widget *widget,
 	if (list)
 		list_add_tail(&widget->work_list, list);
 
+	if (custom_stop_condition && custom_stop_condition(widget, dir))
+		return con;
+
 	if ((widget->is_ep & SND_SOC_DAPM_DIR_TO_EP(dir)) && widget->connected) {
 		widget->endpoints[dir] = snd_soc_dapm_suspend_check(widget);
 		return widget->endpoints[dir];
@@ -1106,7 +1113,7 @@ static __always_inline int is_connected_ep(struct snd_soc_dapm_widget *widget,
 
 		if (path->connect) {
 			path->walking = 1;
-			con += fn(path->node[dir], list);
+			con += fn(path->node[dir], list, custom_stop_condition);
 			path->walking = 0;
 		}
 	}
@@ -1119,23 +1126,37 @@ static __always_inline int is_connected_ep(struct snd_soc_dapm_widget *widget,
 /*
  * Recursively check for a completed path to an active or physically connected
  * output widget. Returns number of complete paths.
+ *
+ * Optionally, can be supplied with a function acting as a stopping condition.
+ * This function takes the dapm widget currently being examined and the walk
+ * direction as an arguments, it should return true if the walk should be
+ * stopped and false otherwise.
  */
 static int is_connected_output_ep(struct snd_soc_dapm_widget *widget,
-	struct list_head *list)
+	struct list_head *list,
+	bool (*custom_stop_condition)(struct snd_soc_dapm_widget *i,
+				      enum snd_soc_dapm_direction))
 {
 	return is_connected_ep(widget, list, SND_SOC_DAPM_DIR_OUT,
-			is_connected_output_ep);
+			is_connected_output_ep, custom_stop_condition);
 }
 
 /*
  * Recursively check for a completed path to an active or physically connected
  * input widget. Returns number of complete paths.
+ *
+ * Optionally, can be supplied with a function acting as a stopping condition.
+ * This function takes the dapm widget currently being examined and the walk
+ * direction as an arguments, it should return true if the walk should be
+ * stopped and false otherwise.
  */
 static int is_connected_input_ep(struct snd_soc_dapm_widget *widget,
-	struct list_head *list)
+	struct list_head *list,
+	bool (*custom_stop_condition)(struct snd_soc_dapm_widget *i,
+				      enum snd_soc_dapm_direction))
 {
 	return is_connected_ep(widget, list, SND_SOC_DAPM_DIR_IN,
-			is_connected_input_ep);
+			is_connected_input_ep, custom_stop_condition);
 }
 
 /**
@@ -1143,15 +1164,24 @@ static int is_connected_input_ep(struct snd_soc_dapm_widget *widget,
  * @dai: the soc DAI.
  * @stream: stream direction.
  * @list: list of active widgets for this stream.
+ * @custom_stop_condition: (optional) a function meant to stop the widget graph
+ *                         walk based on custom logic.
  *
  * Queries DAPM graph as to whether an valid audio stream path exists for
  * the initial stream specified by name. This takes into account
  * current mixer and mux kcontrol settings. Creates list of valid widgets.
  *
+ * Optionally, can be supplied with a function acting as a stopping condition.
+ * This function takes the dapm widget currently being examined and the walk
+ * direction as an arguments, it should return true if the walk should be
+ * stopped and false otherwise.
+ *
  * Returns the number of valid paths or negative error.
  */
 int snd_soc_dapm_dai_get_connected_widgets(struct snd_soc_dai *dai, int stream,
-	struct snd_soc_dapm_widget_list **list)
+	struct snd_soc_dapm_widget_list **list,
+	bool (*custom_stop_condition)(struct snd_soc_dapm_widget *,
+				      enum snd_soc_dapm_direction))
 {
 	struct snd_soc_card *card = dai->component->card;
 	struct snd_soc_dapm_widget *w;
@@ -1171,9 +1201,11 @@ int snd_soc_dapm_dai_get_connected_widgets(struct snd_soc_dai *dai, int stream,
 	}
 
 	if (stream == SNDRV_PCM_STREAM_PLAYBACK)
-		paths = is_connected_output_ep(dai->playback_widget, &widgets);
+		paths = is_connected_output_ep(dai->playback_widget, &widgets,
+				custom_stop_condition);
 	else
-		paths = is_connected_input_ep(dai->capture_widget, &widgets);
+		paths = is_connected_input_ep(dai->capture_widget, &widgets,
+				custom_stop_condition);
 
 	/* Drop starting point */
 	list_del(widgets.next);
@@ -1268,8 +1300,8 @@ static int dapm_generic_check_power(struct snd_soc_dapm_widget *w)
 
 	DAPM_UPDATE_STAT(w, power_checks);
 
-	in = is_connected_input_ep(w, NULL);
-	out = is_connected_output_ep(w, NULL);
+	in = is_connected_input_ep(w, NULL, NULL);
+	out = is_connected_output_ep(w, NULL, NULL);
 	return out != 0 && in != 0;
 }
 
@@ -1928,8 +1960,8 @@ static ssize_t dapm_widget_power_read_file(struct file *file,
 		in = 0;
 		out = 0;
 	} else {
-		in = is_connected_input_ep(w, NULL);
-		out = is_connected_output_ep(w, NULL);
+		in = is_connected_input_ep(w, NULL, NULL);
+		out = is_connected_output_ep(w, NULL, NULL);
 	}
 
 	ret = snprintf(buf, PAGE_SIZE, "%s: %s%s  in %d out %d",
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index aa99dac..c2b0aa8 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1294,7 +1294,8 @@ int dpcm_path_get(struct snd_soc_pcm_runtime *fe,
 	int paths;
 
 	/* get number of valid DAI paths and their widgets */
-	paths = snd_soc_dapm_dai_get_connected_widgets(cpu_dai, stream, list);
+	paths = snd_soc_dapm_dai_get_connected_widgets(cpu_dai, stream, list,
+			NULL);
 
 	dev_dbg(fe->dev, "ASoC: found %d audio %s paths\n", paths,
 			stream ? "capture" : "playback");
-- 
1.7.10.4

[PATCH v3 2/2] ASoC: dpcm: play nice with CODEC<->CODEC links

[Piotr Stankiewicz]

Currently in situations where a normal CODEC to CODEC link follows a
DPCM DAI, an error in the following form will be logged:

ASoC: can't get [playback|capture] BE for <widget name>
ASoC: no BE found for <widget name>

This happens because all widgets in a path containing a DPCM DAI will
be passed to dpcm_add_paths, which will try to interpret the CODEC<->CODEC
as if it were a DPCM DAI, in turn causing the error.

This patch aims to resolve the described issue by stopping the DPCM graph
walk, initiated from dpcm_path_get, at the first widget associated with
a DPCM BE.

Signed-off-by: Piotr Stankiewicz <piotrs@opensource.wolfsonmicro.com>
---
 sound/soc/soc-pcm.c |   42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index c2b0aa8..60d702f 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1287,6 +1287,46 @@ static int widget_in_list(struct snd_soc_dapm_widget_list *list,
 	return 0;
 }
 
+static bool dpcm_end_walk_at_be(struct snd_soc_dapm_widget *widget,
+		enum snd_soc_dapm_direction dir)
+{
+	struct snd_soc_card *card = widget->dapm->card;
+	struct snd_soc_pcm_runtime *rtd;
+	int i;
+
+	if (dir == SND_SOC_DAPM_DIR_OUT) {
+		list_for_each_entry(rtd, &card->rtd_list, list) {
+			if (!rtd->dai_link->no_pcm)
+				continue;
+
+			if (rtd->cpu_dai->playback_widget == widget)
+				return true;
+
+			for (i = 0; i < rtd->num_codecs; ++i) {
+				struct snd_soc_dai *dai = rtd->codec_dais[i];
+				if (dai->playback_widget == widget)
+					return true;
+			}
+		}
+	} else { /* SND_SOC_DAPM_DIR_IN */
+		list_for_each_entry(rtd, &card->rtd_list, list) {
+			if (!rtd->dai_link->no_pcm)
+				continue;
+
+			if (rtd->cpu_dai->capture_widget == widget)
+				return true;
+
+			for (i = 0; i < rtd->num_codecs; ++i) {
+				struct snd_soc_dai *dai = rtd->codec_dais[i];
+				if (dai->capture_widget == widget)
+					return true;
+			}
+		}
+	}
+
+	return false;
+}
+
 int dpcm_path_get(struct snd_soc_pcm_runtime *fe,
 	int stream, struct snd_soc_dapm_widget_list **list)
 {
@@ -1295,7 +1335,7 @@ int dpcm_path_get(struct snd_soc_pcm_runtime *fe,
 
 	/* get number of valid DAI paths and their widgets */
 	paths = snd_soc_dapm_dai_get_connected_widgets(cpu_dai, stream, list,
-			NULL);
+			dpcm_end_walk_at_be);
 
 	dev_dbg(fe->dev, "ASoC: found %d audio %s paths\n", paths,
 			stream ? "capture" : "playback");
-- 
1.7.10.4

Re: [PATCH v3 1/2] ASoC: dapm: support user-defined stop condition in dai_get_connected_widgets

[Mark Brown]

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On Wed, Jun 29, 2016 at 01:32:38PM +0100, Piotr Stankiewicz wrote:
> Certain situations may warrant examining DAPM paths only to a certain
> arbitrary point, as opposed to always following them to the end. For
> instance, when establishing a connection between a front-end DAI link

Please do not submit new versions of already applied patches, please
submit incremental updates to the existing code.  Modifying existing
commits creates problems for other users building on top of those
commits so it's best practice to only change pubished git commits if
absolutely essential.

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