ASoC: component: Add generic PCM copy ops

For following the ALSA PCM core change, a new PCM copy ops is added
toe ASoC component framework: snd_soc_component_driver receives the
copy ops, and snd_soc_pcm_component_copy() helper is provided.

This also fixes a long-standing potential bug where the ASoC driver
covers only copy_user PCM callback and misses the copy from kernel
pointers (such as OSS PCM layer), too.

As of this patch, the old copy_user is still kept, but it'll be
dropped later after all drivers are converted.
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230815190136.8987-19-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/soc-component.h

@@ -141,6 +141,10 @@ struct snd_soc_component_driver {
 			 struct snd_pcm_substream *substream, int channel,
 			 unsigned long pos, void __user *buf,
 			 unsigned long bytes);
+	int (*copy)(struct snd_soc_component *component,
+		    struct snd_pcm_substream *substream, int channel,
+		    unsigned long pos, struct iov_iter *buf,
+		    unsigned long bytes);
 	struct page *(*page)(struct snd_soc_component *component,
 			     struct snd_pcm_substream *substream,
 			     unsigned long offset);
@@ -512,6 +516,9 @@ int snd_soc_pcm_component_sync_stop(struct snd_pcm_substream *substream);
 int snd_soc_pcm_component_copy_user(struct snd_pcm_substream *substream,
 				    int channel, unsigned long pos,
 				    void __user *buf, unsigned long bytes);
+int snd_soc_pcm_component_copy(struct snd_pcm_substream *substream,
+			       int channel, unsigned long pos,
+			       struct iov_iter *buf, unsigned long bytes);
 struct page *snd_soc_pcm_component_page(struct snd_pcm_substream *substream,
 					unsigned long offset);
 int snd_soc_pcm_component_mmap(struct snd_pcm_substream *substream,

sound/soc/soc-component.c

@@ -1052,6 +1052,24 @@ int snd_soc_pcm_component_sync_stop(struct snd_pcm_substream *substream)
 	return 0;
 }
 
+int snd_soc_pcm_component_copy(struct snd_pcm_substream *substream,
+			       int channel, unsigned long pos,
+			       struct iov_iter *buf, unsigned long bytes)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	struct snd_soc_component *component;
+	int i;
+
+	/* FIXME. it returns 1st copy now */
+	for_each_rtd_components(rtd, i, component)
+		if (component->driver->copy)
+			return soc_component_ret(component,
+				component->driver->copy(component, substream,
+					channel, pos, buf, bytes));
+
+	return -EINVAL;
+}
+
 int snd_soc_pcm_component_copy_user(struct snd_pcm_substream *substream,
 				    int channel, unsigned long pos,
 				    void __user *buf, unsigned long bytes)

sound/soc/soc-pcm.c

@@ -2973,7 +2973,9 @@ int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num)
 			rtd->ops.ioctl		= snd_soc_pcm_component_ioctl;
 		if (drv->sync_stop)
 			rtd->ops.sync_stop	= snd_soc_pcm_component_sync_stop;
-		if (drv->copy_user)
+		if (drv->copy)
+			rtd->ops.copy		= snd_soc_pcm_component_copy;
+		else if (drv->copy_user)
 			rtd->ops.copy_user	= snd_soc_pcm_component_copy_user;
 		if (drv->page)
 			rtd->ops.page		= snd_soc_pcm_component_page;