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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: Keith Milner <kamilner@superlative.org>
Tested-by: Dylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-6-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2020-11-23 09:53:11 +01:00
parent 2e43aae2bf
commit c7474d0977
2 changed files with 31 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
sound/usb/endpoint.c
View File

@ -439,6 +439,26 @@ static void snd_complete_urb(struct urb *urb)
clear_bit(ctx->index, &ep->active_mask); 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 * 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); mutex_lock(&chip->mutex);
list_for_each_entry(ep, &chip->ep_list, list) { ep = snd_usb_get_endpoint(chip, ep_num,
if (ep->ep_num == ep_num && alts->desc.bInterfaceNumber,
ep->iface == alts->desc.bInterfaceNumber && alts->desc.bAlternateSetting);
ep->altsetting == alts->desc.bAlternateSetting) { if (ep) {
usb_audio_dbg(ep->chip, usb_audio_dbg(ep->chip, "Re-using EP %x in iface %d,%d @%p\n",
"Re-using EP %x in iface %d,%d @%p\n", ep_num, ep->iface, ep->altsetting, ep);
ep_num, ep->iface, ep->altsetting, ep); goto __exit_unlock;
goto __exit_unlock;
}
} }
usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n", usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n",

4
sound/usb/endpoint.h
View File

@ -5,6 +5,10 @@
#define SND_USB_ENDPOINT_TYPE_DATA 0 #define SND_USB_ENDPOINT_TYPE_DATA 0
#define SND_USB_ENDPOINT_TYPE_SYNC 1 #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 snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
struct usb_host_interface *alts, struct usb_host_interface *alts,
int ep_num, int direction, int type); int ep_num, int direction, int type);