Commit c7474d09 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: usb-audio: Add snd_usb_get_endpoint() helper 



Factor out the code to obtain snd_usb_endpoint object matching with
the given endpoint.  It'll be used in the later patch to add the
implicit feedback hw-constraint.

No functional change by this patch itself.

Tested-by: default avatarKeith Milner <kamilner@superlative.org>
Tested-by: default avatarDylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-6-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 2e43aae2

sound/usb/endpoint.c

+27 −9
Original line number Diff line number Diff line
@@ -439,6 +439,26 @@ static void snd_complete_urb(struct urb *urb) 
	clear_bit(ctx->index, &ep->active_mask);

}



/*

 * Get the existing endpoint object corresponding EP, iface and alt numbers

 * Returns NULL if not present.

 * Call inside chip->mutex locking for avoiding the race.

 */

struct snd_usb_endpoint *

snd_usb_get_endpoint(struct snd_usb_audio *chip,

		     int ep_num, int iface, int altsetting)

{

	struct snd_usb_endpoint *ep;



	list_for_each_entry(ep, &chip->ep_list, list) {

		if (ep->ep_num == ep_num &&

		    ep->iface == iface &&

		    ep->altsetting == altsetting)

			return ep;

	}

	return NULL;

}



/**

 * snd_usb_add_endpoint: Add an endpoint to an USB audio chip

 *
@@ -470,16 +490,14 @@ struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip, 


	mutex_lock(&chip->mutex);



	list_for_each_entry(ep, &chip->ep_list, list) {

		if (ep->ep_num == ep_num &&

		    ep->iface == alts->desc.bInterfaceNumber &&

		    ep->altsetting == alts->desc.bAlternateSetting) {

			usb_audio_dbg(ep->chip,

				      "Re-using EP %x in iface %d,%d @%p\n",

	ep = snd_usb_get_endpoint(chip, ep_num,

				  alts->desc.bInterfaceNumber,

				  alts->desc.bAlternateSetting);

	if (ep) {

		usb_audio_dbg(ep->chip, "Re-using EP %x in iface %d,%d @%p\n",

			      ep_num, ep->iface, ep->altsetting, ep);

		goto __exit_unlock;

	}

	}



	usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n",

		    is_playback ? "playback" : "capture",

sound/usb/endpoint.h

+4 −0
Original line number Diff line number Diff line
@@ -5,6 +5,10 @@ 
#define SND_USB_ENDPOINT_TYPE_DATA     0

#define SND_USB_ENDPOINT_TYPE_SYNC     1



struct snd_usb_endpoint *snd_usb_get_endpoint(struct snd_usb_audio *chip,

					      int ep_num, int iface,

					      int altsetting);



struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,

					      struct usb_host_interface *alts,

					      int ep_num, int direction, int type);