ALSA: emu10k1: refactor PCM playback cache filling

Rename snd_emu10k1_playback_invalidate_cache() to the more apt
snd_emu10k1_playback_fill_cache(), and factor out
snd_emu10k1_playback_prepare_voices(), which calls the former for all
channels.
Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Link: https://lore.kernel.org/r/20230517174256.3657060-8-oswald.buddenhagen@gmx.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/emu10k1/emupcm.c

@@ -511,16 +511,12 @@ static int snd_emu10k1_capture_prepare(struct snd_pcm_substream *substream)
 	return 0;
 }
 
-static void snd_emu10k1_playback_invalidate_cache(struct snd_emu10k1 *emu,
-						  struct snd_emu10k1_voice *evoice,
-						  bool w_16, bool stereo)
+static void snd_emu10k1_playback_fill_cache(struct snd_emu10k1 *emu,
+					    unsigned voice,
+					    u32 sample, bool stereo)
 {
-	unsigned voice, sample;
 	u32 ccr;
 
-	voice = evoice->number;
-	sample = w_16 ? 0 : 0x80808080;
-
 	// We assume that the cache is resting at this point (i.e.,
 	// CCR_CACHEINVALIDSIZE is very small).
 
@@ -539,6 +535,22 @@ static void snd_emu10k1_playback_invalidate_cache(struct snd_emu10k1 *emu,
 	snd_emu10k1_ptr_write(emu, CCR, voice, ccr);
 }
 
+static void snd_emu10k1_playback_prepare_voices(struct snd_emu10k1 *emu,
+						struct snd_emu10k1_pcm *epcm,
+						bool w_16, bool stereo,
+						int channels)
+{
+	u32 sample = w_16 ? 0 : 0x80808080;
+
+	for (int i = 0; i < channels; i++) {
+		unsigned voice = epcm->voices[i]->number;
+		snd_emu10k1_playback_fill_cache(emu, voice, sample, stereo);
+	}
+
+	// It takes a moment until the cache fills complete,
+	// but the unmuting takes long enough for that.
+}
+
 static void snd_emu10k1_playback_commit_volume(struct snd_emu10k1 *emu,
 					       struct snd_emu10k1_voice *evoice,
 					       unsigned int vattn)
@@ -632,7 +644,7 @@ static int snd_emu10k1_playback_trigger(struct snd_pcm_substream *substream,
 	spin_lock(&emu->reg_lock);
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
-		snd_emu10k1_playback_invalidate_cache(emu, epcm->voices[0], w_16, stereo);
+		snd_emu10k1_playback_prepare_voices(emu, epcm, w_16, stereo, 1);
 		fallthrough;
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 	case SNDRV_PCM_TRIGGER_RESUME:
@@ -774,10 +786,7 @@ static int snd_emu10k1_efx_playback_trigger(struct snd_pcm_substream *substream,
 	spin_lock(&emu->reg_lock);
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
-		/* prepare voices */
-		for (i = 0; i < NUM_EFX_PLAYBACK; i++) {	
-			snd_emu10k1_playback_invalidate_cache(emu, epcm->voices[i], true, false);
-		}
+		snd_emu10k1_playback_prepare_voices(emu, epcm, true, false, NUM_EFX_PLAYBACK);
 		fallthrough;
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 	case SNDRV_PCM_TRIGGER_RESUME: