Re: [PATCH v5 12/32] sound: usb: Export USB SND APIs for modules

On 8/29/2023 11:06 PM, Wesley Cheng wrote:

Some vendor modules will utilize useful parsing and endpoint management APIs to start audio playback/capture.

Signed-off-by: Wesley Cheng quic_wcheng@quicinc.com

sound/usb/card.c | 4 +++ sound/usb/endpoint.c | 1 + sound/usb/helper.c | 1 + sound/usb/pcm.c | 67 +++++++++++++++++++++++++++++++++----------- sound/usb/pcm.h | 11 ++++++++ 5 files changed, 67 insertions(+), 17 deletions(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c index 067a1e82f4bf..b45b6daee7b7 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -1053,6 +1053,7 @@ int snd_usb_lock_shutdown(struct snd_usb_audio *chip) wake_up(&chip->shutdown_wait); return err; } +EXPORT_SYMBOL_GPL(snd_usb_lock_shutdown);

/* autosuspend and unlock the shutdown */ void snd_usb_unlock_shutdown(struct snd_usb_audio *chip) @@ -1061,6 +1062,7 @@ void snd_usb_unlock_shutdown(struct snd_usb_audio *chip) if (atomic_dec_and_test(&chip->usage_count)) wake_up(&chip->shutdown_wait); } +EXPORT_SYMBOL_GPL(snd_usb_unlock_shutdown);

int snd_usb_autoresume(struct snd_usb_audio *chip) { @@ -1083,6 +1085,7 @@ int snd_usb_autoresume(struct snd_usb_audio *chip) } return 0; } +EXPORT_SYMBOL_GPL(snd_usb_autoresume);

void snd_usb_autosuspend(struct snd_usb_audio *chip) { @@ -1096,6 +1099,7 @@ void snd_usb_autosuspend(struct snd_usb_audio *chip) for (i = 0; i < chip->num_interfaces; i++) usb_autopm_put_interface(chip->intf[i]); } +EXPORT_SYMBOL_GPL(snd_usb_autosuspend);

static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message) { diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index a385e85c4650..aac92e0b8aa2 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -1503,6 +1503,7 @@ int snd_usb_endpoint_prepare(struct snd_usb_audio *chip, mutex_unlock(&chip->mutex); return err; } +EXPORT_SYMBOL_GPL(snd_usb_endpoint_prepare);

/* get the current rate set to the given clock by any endpoint */ int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock) diff --git a/sound/usb/helper.c b/sound/usb/helper.c index bf80e55d013a..4322ae3738e6 100644 --- a/sound/usb/helper.c +++ b/sound/usb/helper.c @@ -62,6 +62,7 @@ void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype } return NULL; } +EXPORT_SYMBOL_GPL(snd_usb_find_csint_desc);

/*

• Wrapper for usb_control_msg().

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index 08bf535ed163..999f66080649 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -148,6 +148,16 @@ find_format(struct list_head *fmt_list_head, snd_pcm_format_t format, return found; }

+const struct audioformat * +snd_usb_find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,

•    unsigned int rate, unsigned int channels, bool strict_match,
  

•    struct snd_usb_substream *subs)
  

+{

• return find_format(fmt_list_head, format, rate, channels, strict_match,

• 	subs);
  

+} +EXPORT_SYMBOL_GPL(snd_usb_find_format);

• static const struct audioformat * find_substream_format(struct snd_usb_substream *subs, const struct snd_pcm_hw_params *params)

@@ -157,6 +167,14 @@ find_substream_format(struct snd_usb_substream *subs, true, subs); }

+const struct audioformat * +snd_usb_find_substream_format(struct snd_usb_substream *subs,

•       const struct snd_pcm_hw_params *params)
  

+{

• return find_substream_format(subs, params);

+} +EXPORT_SYMBOL_GPL(snd_usb_find_substream_format);

• bool snd_usb_pcm_has_fixed_rate(struct snd_usb_substream *subs) { const struct audioformat *fp;

@@ -461,20 +479,9 @@ static void close_endpoints(struct snd_usb_audio *chip, } }

-/*

• • hw_params callback
• • allocate a buffer and set the given audio format.
• • so far we use a physically linear buffer although packetize transfer
• • doesn't need a continuous area.
• • if sg buffer is supported on the later version of alsa, we'll follow
• • that.
• */

-static int snd_usb_hw_params(struct snd_pcm_substream *substream,

• 	     struct snd_pcm_hw_params *hw_params)
  

+int snd_usb_attach_endpoints(struct snd_usb_substream *subs,

• 		struct snd_pcm_hw_params *hw_params)
  

  {

• struct snd_usb_substream *subs = substream->runtime->private_data; struct snd_usb_audio *chip = subs->stream->chip; const struct audioformat *fmt; const struct audioformat *sync_fmt;

@@ -499,7 +506,7 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream, if (fmt->implicit_fb) { sync_fmt = snd_usb_find_implicit_fb_sync_format(chip, fmt, hw_params,

• 						!substream->stream,
  

• 						!subs->direction,
  					&sync_fixed_rate);
  

  if (!sync_fmt) { usb_audio_dbg(chip,

@@ -579,15 +586,28 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,

return ret; } +EXPORT_SYMBOL_GPL(snd_usb_attach_endpoints);

/*

• • hw_free callback

• • hw_params callback

• • reset the audio format and release the buffer

• • allocate a buffer and set the given audio format.
• • so far we use a physically linear buffer although packetize transfer
• • doesn't need a continuous area.
• • if sg buffer is supported on the later version of alsa, we'll follow
• • that.
  */

-static int snd_usb_hw_free(struct snd_pcm_substream *substream) +static int snd_usb_hw_params(struct snd_pcm_substream *substream,

• 	     struct snd_pcm_hw_params *hw_params)
  

  { struct snd_usb_substream *subs = substream->runtime->private_data;
• return snd_usb_attach_endpoints(subs, hw_params);

+}

+int snd_usb_detach_endpoint(struct snd_usb_substream *subs) +{ struct snd_usb_audio *chip = subs->stream->chip;

snd_media_stop_pipeline(subs); @@ -603,6 +623,19 @@ static int snd_usb_hw_free(struct snd_pcm_substream *substream)

return 0; } +EXPORT_SYMBOL_GPL(snd_usb_detach_endpoint);

+/*

• • hw_free callback
• • reset the audio format and release the buffer
• */

+static int snd_usb_hw_free(struct snd_pcm_substream *substream) +{

• struct snd_usb_substream *subs = substream->runtime->private_data;
• return snd_usb_detach_endpoint(subs);

+}

/* free-wheeling mode? (e.g. dmix) */ static int in_free_wheeling_mode(struct snd_pcm_runtime *runtime) diff --git a/sound/usb/pcm.h b/sound/usb/pcm.h index 388fe2ba346d..e36df3611a05 100644 --- a/sound/usb/pcm.h +++ b/sound/usb/pcm.h @@ -15,4 +15,15 @@ void snd_usb_preallocate_buffer(struct snd_usb_substream *subs); int snd_usb_audioformat_set_sync_ep(struct snd_usb_audio *chip, struct audioformat *fmt);

+const struct audioformat * +snd_usb_find_format(struct list_head *fmt_list_head, snd_pcm_format_t format,

•    unsigned int rate, unsigned int channels, bool strict_match,
  

•    struct snd_usb_substream *subs);
  

+const struct audioformat * +snd_usb_find_substream_format(struct snd_usb_substream *subs,

•       const struct snd_pcm_hw_params *params);
  

+int snd_usb_attach_endpoints(struct snd_usb_substream *subs,

• 		struct snd_pcm_hw_params *hw_params);
  

+int snd_usb_detach_endpoint(struct snd_usb_substream *subs); #endif /* __USBAUDIO_PCM_H */

Why is it multiple "endpoints" when attaching, but only one "endpoint" when detaching? Both seem to be getting similar arguments.