ASoC: dwc: Use managed buffer allocation

Clean up the drivers with the new managed buffer allocation API.
The superfluous snd_pcm_lib_malloc_pages() and
snd_pcm_lib_free_pages() calls are dropped, as well as the superfluous
snd_pcm_lib_preallocate_free_for_all() call.  As of the result,
hw_free and pcm_destruct ops became empty and got removed.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20191210142614.19405-4-tiwai@suse.deSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/dwc/dwc-pcm.c

@@ -162,7 +162,6 @@ static int dw_pcm_hw_params(struct snd_soc_component *component,
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct dw_i2s_dev *dev = runtime->private_data;
-	int ret;
 
 	switch (params_channels(hw_params)) {
 	case 2:
@@ -187,18 +186,7 @@ static int dw_pcm_hw_params(struct snd_soc_component *component,
 		return -EINVAL;
 	}
 
-	ret = snd_pcm_lib_malloc_pages(substream,
-			params_buffer_bytes(hw_params));
-	if (ret < 0)
-		return ret;
-	else
-		return 0;
-}
-
-static int dw_pcm_hw_free(struct snd_soc_component *component,
-			  struct snd_pcm_substream *substream)
-{
-	return snd_pcm_lib_free_pages(substream);
+	return 0;
 }
 
 static int dw_pcm_trigger(struct snd_soc_component *component,
@@ -256,27 +244,19 @@ static int dw_pcm_new(struct snd_soc_component *component,
 {
 	size_t size = dw_pcm_hardware.buffer_bytes_max;
 
-	snd_pcm_lib_preallocate_pages_for_all(rtd->pcm,
+	snd_pcm_set_managed_buffer_all(rtd->pcm,
 			SNDRV_DMA_TYPE_CONTINUOUS,
 			NULL, size, size);
 	return 0;
 }
 
-static void dw_pcm_free(struct snd_soc_component *component,
-			struct snd_pcm *pcm)
-{
-	snd_pcm_lib_preallocate_free_for_all(pcm);
-}
-
 static const struct snd_soc_component_driver dw_pcm_component = {
 	.open		= dw_pcm_open,
 	.close		= dw_pcm_close,
 	.hw_params	= dw_pcm_hw_params,
-	.hw_free	= dw_pcm_hw_free,
 	.trigger	= dw_pcm_trigger,
 	.pointer	= dw_pcm_pointer,
 	.pcm_construct	= dw_pcm_new,
-	.pcm_destruct	= dw_pcm_free,
 };
 
 int dw_pcm_register(struct platform_device *pdev)