ASoC: soc-pcm: add dpcm_runtime_setup_fe()

dpcm_fe_dai_startup() (= A) calls dpcm_set_fe_runtime() (= B) to setup
DPCM runtime. From *naming point of view*, it sounds like setup function
for FE.

(A)	static int dpcm_fe_dai_startup(...)
	{
		...
(B)		dpcm_set_fe_runtime(...);
		...
	}

But in dpcm_set_fe_runtime() (= B),
It  setups FE by for_each loop (= X),
and setups BE by dpcm_runtime_merge_xxx() (= Y).

(B)	static void dpcm_set_fe_runtime(...)
	{
		...
 ^		for_each_rtd_cpu_dais(...) {
 |			...
(X)			soc_pcm_hw_update_rate(...);
 |			soc_pcm_hw_update_chan(...);
 |			soc_pcm_hw_update_format(...);
 v		}

 ^		dpcm_runtime_merge_format(...);
(Y)		dpcm_runtime_merge_chan(...);
 v		dpcm_runtime_merge_rate(...);
	}

These means that the function which is called as xxx_fe_xxx()
is setups both FE and BE. This is confusable and can be hot bed for bug.

To tidyup it, as 1st step, this patch adds new dpcm_runtime_setup_fe()
for (X).
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87pn0tvsgx.wl-kuninori.morimoto.gx@renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-pcm.c

@@ -1526,6 +1526,36 @@ int dpcm_be_dai_startup(struct snd_soc_pcm_runtime *fe, int stream)
 	return err;
 }
 
+static void dpcm_runtime_setup_fe(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *fe = asoc_substream_to_rtd(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_pcm_hardware *hw = &runtime->hw;
+	struct snd_soc_dai *dai;
+	int stream = substream->stream;
+	int i;
+
+	soc_pcm_hw_init(hw);
+
+	for_each_rtd_cpu_dais(fe, i, dai) {
+		struct snd_soc_pcm_stream *cpu_stream;
+
+		/*
+		 * Skip CPUs which don't support the current stream
+		 * type. See soc_pcm_init_runtime_hw() for more details
+		 */
+		if (!snd_soc_dai_stream_valid(dai, stream))
+			continue;
+
+		cpu_stream = snd_soc_dai_get_pcm_stream(dai, stream);
+
+		soc_pcm_hw_update_rate(hw, cpu_stream);
+		soc_pcm_hw_update_chan(hw, cpu_stream);
+		soc_pcm_hw_update_format(hw, cpu_stream);
+	}
+
+}
+
 static void dpcm_runtime_merge_format(struct snd_pcm_substream *substream,
 				      struct snd_pcm_runtime *runtime)
 {
@@ -1651,29 +1681,8 @@ static void dpcm_runtime_merge_rate(struct snd_pcm_substream *substream,
 static void dpcm_set_fe_runtime(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
-	struct snd_pcm_hardware *hw = &runtime->hw;
-	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
-	struct snd_soc_dai *cpu_dai;
-	int i;
 
-	soc_pcm_hw_init(hw);
-
-	for_each_rtd_cpu_dais(rtd, i, cpu_dai) {
-		struct snd_soc_pcm_stream *stream;
-
-		/*
-		 * Skip CPUs which don't support the current stream
-		 * type. See soc_pcm_init_runtime_hw() for more details
-		 */
-		if (!snd_soc_dai_stream_valid(cpu_dai, substream->stream))
-			continue;
-
-		stream = snd_soc_dai_get_pcm_stream(cpu_dai, substream->stream);
-
-		soc_pcm_hw_update_rate(hw, stream);
-		soc_pcm_hw_update_chan(hw, stream);
-		soc_pcm_hw_update_format(hw, stream);
-	}
+	dpcm_runtime_setup_fe(substream);
 
 	dpcm_runtime_merge_format(substream, runtime);
 	dpcm_runtime_merge_chan(substream, runtime);