linux/sound/usb/implicit.c

// SPDX-License-Identifier: GPL-2.0-or-later
//
// Special handling for implicit feedback mode
//

#include <linux/init.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>

#include "usbaudio.h"
#include "card.h"
#include "helper.h"
#include "pcm.h"
#include "implicit.h"

enum { … };

struct snd_usb_implicit_fb_match { … };

#define IMPLICIT_FB_GENERIC_DEV(vend, prod) …
#define IMPLICIT_FB_FIXED_DEV(vend, prod, ep, ifnum) …
#define IMPLICIT_FB_BOTH_DEV(vend, prod, ep, ifnum) …
#define IMPLICIT_FB_SKIP_DEV(vend, prod) …

/* Implicit feedback quirk table for playback */
static const struct snd_usb_implicit_fb_match playback_implicit_fb_quirks[] = …;

/* Implicit feedback quirk table for capture: only FIXED type */
static const struct snd_usb_implicit_fb_match capture_implicit_fb_quirks[] = …;

/* set up sync EP information on the audioformat */
static int add_implicit_fb_sync_ep(struct snd_usb_audio *chip,
				   struct audioformat *fmt,
				   int ep, int ep_idx, int ifnum,
				   const struct usb_host_interface *alts)
{ … }

/* Check whether the given UAC2 iface:altset points to an implicit fb source */
static int add_generic_uac2_implicit_fb(struct snd_usb_audio *chip,
					struct audioformat *fmt,
					unsigned int ifnum,
					unsigned int altsetting)
{ … }

static bool roland_sanity_check_iface(struct usb_host_interface *alts)
{ … }

/* Like the UAC2 case above, but specific to Roland with vendor class and hack */
static int add_roland_implicit_fb(struct snd_usb_audio *chip,
				  struct audioformat *fmt,
				  struct usb_host_interface *alts)
{ … }

/* capture quirk for Roland device; always full-duplex */
static int add_roland_capture_quirk(struct snd_usb_audio *chip,
				    struct audioformat *fmt,
				    struct usb_host_interface *alts)
{ … }

/* Playback and capture EPs on Pioneer devices share the same iface/altset
 * for the implicit feedback operation
 */
static bool is_pioneer_implicit_fb(struct snd_usb_audio *chip,
				   struct usb_host_interface *alts)

{ … }

static int __add_generic_implicit_fb(struct snd_usb_audio *chip,
				     struct audioformat *fmt,
				     int iface, int altset)
{ … }

/* More generic quirk: look for the sync EP next to the data EP */
static int add_generic_implicit_fb(struct snd_usb_audio *chip,
				   struct audioformat *fmt,
				   struct usb_host_interface *alts)
{ … }

static const struct snd_usb_implicit_fb_match *
find_implicit_fb_entry(struct snd_usb_audio *chip,
		       const struct snd_usb_implicit_fb_match *match,
		       const struct usb_host_interface *alts)
{ … }

/* Setup an implicit feedback endpoint from a quirk. Returns 0 if no quirk
 * applies. Returns 1 if a quirk was found.
 */
static int audioformat_implicit_fb_quirk(struct snd_usb_audio *chip,
					 struct audioformat *fmt,
					 struct usb_host_interface *alts)
{ … }

/* same for capture, but only handling FIXED entry */
static int audioformat_capture_quirk(struct snd_usb_audio *chip,
				     struct audioformat *fmt,
				     struct usb_host_interface *alts)
{ … }

/*
 * Parse altset and set up implicit feedback endpoint on the audioformat
 */
int snd_usb_parse_implicit_fb_quirk(struct snd_usb_audio *chip,
				    struct audioformat *fmt,
				    struct usb_host_interface *alts)
{ … }

/*
 * Return the score of matching two audioformats.
 * Veto the audioformat if:
 * - It has no channels for some reason.
 * - Requested PCM format is not supported.
 * - Requested sample rate is not supported.
 */
static int match_endpoint_audioformats(struct snd_usb_substream *subs,
				       const struct audioformat *fp,
				       int rate, int channels,
				       snd_pcm_format_t pcm_format)
{ … }

static struct snd_usb_substream *
find_matching_substream(struct snd_usb_audio *chip, int stream, int ep_num,
			int fmt_type)
{ … }

/*
 * Return the audioformat that is suitable for the implicit fb
 */
const struct audioformat *
snd_usb_find_implicit_fb_sync_format(struct snd_usb_audio *chip,
				     const struct audioformat *target,
				     const struct snd_pcm_hw_params *params,
				     int stream,
				     bool *fixed_rate)
{ … }