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
......@@ -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
*
......@@ -470,15 +490,13 @@ 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_num, ep->iface, ep->altsetting, ep);
goto __exit_unlock;
}
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",
......
......@@ -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);
......
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