Merge series "simple-audio-card codec2codec support" from Samuel Holland <samuel@sholland.org>:

We are currently using simple-audio-card on the Allwinner A64 SoC.
The digital audio codec there (sun8i-codec) has 3 AIFs, one each for the
CPU, the modem, and Bluetooth. Adding support for the secondary AIFs
requires adding codec2codec DAI links.

Since the modem and bt-sco codec DAI drivers only have one set of
possible PCM parameters (namely, 8kHz mono S16LE), there's no real
need for a machine driver to specify the DAI link configuration. The
parameters for these "simple" DAI links can be chosen automatically.

This series adds codec2codec DAI link support to simple-audio-card.
Codec to codec links are automatically detected when all DAIs in the
link belong to codec components.

I tried to reuse as much code as possible, so the first two patches
refactor a couple of helper functions to be more generic.

The last patch adds the new feature and its documentation.

Changes in v4:
  - Rebased on top of asoc/for-next, several changes to patch 2
  - Removed unused variable from patch 3
Changes in v3:
  - Update use of for_each_rtd_components for v5.6
Changes in v2:
  - Drop patch 1 as it was merged
  - Automatically detect codec2codec links instead of using a DT property

Samuel Holland (3):
  ALSA: pcm: Add a standalone version of snd_pcm_limit_hw_rates
  ASoC: pcm: Export parameter intersection logic
  ASoC: simple-card: Add support for codec2codec DAI links

 Documentation/sound/soc/codec-to-codec.rst |  9 +++-
 include/sound/pcm.h                        |  9 +++-
 include/sound/soc.h                        |  3 ++
 sound/core/pcm_misc.c                      | 18 +++----
 sound/soc/generic/simple-card-utils.c      | 48 ++++++++++++++++++
 sound/soc/soc-pcm.c                        | 59 ++++++++++++++--------
 6 files changed, 114 insertions(+), 32 deletions(-)

--
2.24.1

3 files changed, 95 insertions, 27 deletions

diff --git a/sound/core/pcm_misc.c b/sound/core/pcm_misc.c
index a6a541511534..5dd2e5335900 100644
--- a/sound/core/pcm_misc.c
+++ b/sound/core/pcm_misc.c
@@ -474,32 +474,32 @@ int snd_pcm_format_set_silence(snd_pcm_format_t format, void *data, unsigned int
 EXPORT_SYMBOL(snd_pcm_format_set_silence);
 
 /**
- * snd_pcm_limit_hw_rates - determine rate_min/rate_max fields
- * @runtime: the runtime instance
+ * snd_pcm_hw_limit_rates - determine rate_min/rate_max fields
+ * @hw: the pcm hw instance
  *
  * Determines the rate_min and rate_max fields from the rates bits of
- * the given runtime->hw.
+ * the given hw.
  *
  * Return: Zero if successful.
  */
-int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime)
+int snd_pcm_hw_limit_rates(struct snd_pcm_hardware *hw)
 {
 	int i;
 	for (i = 0; i < (int)snd_pcm_known_rates.count; i++) {
-		if (runtime->hw.rates & (1 << i)) {
-			runtime->hw.rate_min = snd_pcm_known_rates.list[i];
+		if (hw->rates & (1 << i)) {
+			hw->rate_min = snd_pcm_known_rates.list[i];
 			break;
 		}
 	}
 	for (i = (int)snd_pcm_known_rates.count - 1; i >= 0; i--) {
-		if (runtime->hw.rates & (1 << i)) {
-			runtime->hw.rate_max = snd_pcm_known_rates.list[i];
+		if (hw->rates & (1 << i)) {
+			hw->rate_max = snd_pcm_known_rates.list[i];
 			break;
 		}
 	}
 	return 0;
 }
-EXPORT_SYMBOL(snd_pcm_limit_hw_rates);
+EXPORT_SYMBOL(snd_pcm_hw_limit_rates);
 
 /**
  * snd_pcm_rate_to_rate_bit - converts sample rate to SNDRV_PCM_RATE_xxx bit
diff --git a/sound/soc/generic/simple-card-utils.c b/sound/soc/generic/simple-card-utils.c
index 9b794775df53..320e648f7499 100644
--- a/sound/soc/generic/simple-card-utils.c
+++ b/sound/soc/generic/simple-card-utils.c
@@ -331,6 +331,50 @@ static int asoc_simple_init_dai(struct snd_soc_dai *dai,
 	return 0;
 }
 
+static int asoc_simple_init_dai_link_params(struct snd_soc_pcm_runtime *rtd,
+					    struct simple_dai_props *dai_props)
+{
+	struct snd_soc_dai_link *dai_link = rtd->dai_link;
+	struct snd_soc_component *component;
+	struct snd_soc_pcm_stream *params;
+	struct snd_pcm_hardware hw;
+	int i, ret, stream;
+
+	/* Only codecs should have non_legacy_dai_naming set. */
+	for_each_rtd_components(rtd, i, component) {
+		if (!component->driver->non_legacy_dai_naming)
+			return 0;
+	}
+
+	/* Assumes the capabilities are the same for all supported streams */
+	for (stream = 0; stream < 2; stream++) {
+		ret = snd_soc_runtime_calc_hw(rtd, &hw, stream);
+		if (ret == 0)
+			break;
+	}
+
+	if (ret < 0) {
+		dev_err(rtd->dev, "simple-card: no valid dai_link params\n");
+		return ret;
+	}
+
+	params = devm_kzalloc(rtd->dev, sizeof(*params), GFP_KERNEL);
+	if (!params)
+		return -ENOMEM;
+
+	params->formats = hw.formats;
+	params->rates = hw.rates;
+	params->rate_min = hw.rate_min;
+	params->rate_max = hw.rate_max;
+	params->channels_min = hw.channels_min;
+	params->channels_max = hw.channels_max;
+
+	dai_link->params = params;
+	dai_link->num_params = 1;
+
+	return 0;
+}
+
 int asoc_simple_dai_init(struct snd_soc_pcm_runtime *rtd)
 {
 	struct asoc_simple_priv *priv = snd_soc_card_get_drvdata(rtd->card);
@@ -347,6 +391,10 @@ int asoc_simple_dai_init(struct snd_soc_pcm_runtime *rtd)
 	if (ret < 0)
 		return ret;
 
+	ret = asoc_simple_init_dai_link_params(rtd, dai_props);
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(asoc_simple_dai_init);
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index e3a2c4f7757b..de4226357e2b 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -587,11 +587,18 @@ static void soc_pcm_apply_msb(struct snd_pcm_substream *substream)
 	soc_pcm_set_msb(substream, cpu_bits);
 }
 
-static void soc_pcm_init_runtime_hw(struct snd_pcm_substream *substream)
+/**
+ * snd_soc_runtime_calc_hw() - Calculate hw limits for a PCM stream
+ * @rtd: ASoC PCM runtime
+ * @hw: PCM hardware parameters (output)
+ * @stream: Direction of the PCM stream
+ *
+ * Calculates the subset of stream parameters supported by all DAIs
+ * associated with the PCM stream.
+ */
+int snd_soc_runtime_calc_hw(struct snd_soc_pcm_runtime *rtd,
+			    struct snd_pcm_hardware *hw, int stream)
 {
-	struct snd_pcm_runtime *runtime = substream->runtime;
-	struct snd_pcm_hardware *hw = &runtime->hw;
-	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct snd_soc_dai *codec_dai;
 	struct snd_soc_dai *cpu_dai;
 	struct snd_soc_pcm_stream *codec_stream;
@@ -602,7 +609,6 @@ static void soc_pcm_init_runtime_hw(struct snd_pcm_substream *substream)
 	unsigned int cpu_rate_min = 0, cpu_rate_max = UINT_MAX;
 	unsigned int rates = UINT_MAX, cpu_rates = UINT_MAX;
 	u64 formats = ULLONG_MAX;
-	int stream = substream->stream;
 	int i;
 
 	/* first calculate min/max only for CPUs in the DAI link */
@@ -613,12 +619,8 @@ static void soc_pcm_init_runtime_hw(struct snd_pcm_substream *substream)
 		 * Otherwise, since the rate, channel, and format values will
 		 * zero in that case, we would have no usable settings left,
 		 * causing the resulting setup to fail.
-		 * At least one CPU should match, otherwise we should have
-		 * bailed out on a higher level, since there would be no
-		 * CPU to support the transfer direction in that case.
 		 */
-		if (!snd_soc_dai_stream_valid(cpu_dai,
-					      substream->stream))
+		if (!snd_soc_dai_stream_valid(cpu_dai, stream))
 			continue;
 
 		cpu_stream = snd_soc_dai_get_pcm_stream(cpu_dai, stream);
@@ -640,9 +642,6 @@ static void soc_pcm_init_runtime_hw(struct snd_pcm_substream *substream)
 		 * Otherwise, since the rate, channel, and format values will
 		 * zero in that case, we would have no usable settings left,
 		 * causing the resulting setup to fail.
-		 * At least one CODEC should match, otherwise we should have
-		 * bailed out on a higher level, since there would be no
-		 * CODEC to support the transfer direction in that case.
 		 */
 		if (!snd_soc_dai_stream_valid(codec_dai, stream))
 			continue;
@@ -657,6 +656,10 @@ static void soc_pcm_init_runtime_hw(struct snd_pcm_substream *substream)
 		rates = snd_pcm_rate_mask_intersect(codec_stream->rates, rates);
 	}
 
+	/* Verify both a valid CPU DAI and a valid CODEC DAI were found */
+	if (!chan_min || !cpu_chan_min)
+		return -EINVAL;
+
 	/*
 	 * chan min/max cannot be enforced if there are multiple CODEC DAIs
 	 * connected to CPU DAI(s), use CPU DAI's directly and let
@@ -670,18 +673,35 @@ static void soc_pcm_init_runtime_hw(struct snd_pcm_substream *substream)
 	/* finally find a intersection between CODECs and CPUs */
 	hw->channels_min = max(chan_min, cpu_chan_min);
 	hw->channels_max = min(chan_max, cpu_chan_max);
-	if (hw->formats)
-		hw->formats &= formats;
-	else
-		hw->formats = formats;
+	hw->formats = formats;
 	hw->rates = snd_pcm_rate_mask_intersect(rates, cpu_rates);
 
-	snd_pcm_limit_hw_rates(runtime);
+	snd_pcm_hw_limit_rates(hw);
 
 	hw->rate_min = max(hw->rate_min, cpu_rate_min);
 	hw->rate_min = max(hw->rate_min, rate_min);
 	hw->rate_max = min_not_zero(hw->rate_max, cpu_rate_max);
 	hw->rate_max = min_not_zero(hw->rate_max, rate_max);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_runtime_calc_hw);
+
+static void soc_pcm_init_runtime_hw(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_hardware *hw = &substream->runtime->hw;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	u64 formats = hw->formats;
+
+	/*
+	 * At least one CPU and one CODEC should match. Otherwise, we should
+	 * have bailed out on a higher level, since there would be no CPU or
+	 * CODEC to support the transfer direction in that case.
+	 */
+	snd_soc_runtime_calc_hw(rtd, hw, substream->stream);
+
+	if (formats)
+		hw->formats &= formats;
 }
 
 static int soc_pcm_components_open(struct snd_pcm_substream *substream)