86 lines
2 KiB
C
86 lines
2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* u_audio.h -- interface to USB gadget "ALSA sound card" utilities
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*
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* Copyright (C) 2016
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* Author: Ruslan Bilovol <ruslan.bilovol@gmail.com>
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*/
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#ifndef __U_AUDIO_H
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#define __U_AUDIO_H
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#include <linux/usb/composite.h>
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struct uac_params {
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/* playback */
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int p_chmask; /* channel mask */
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int p_srate; /* rate in Hz */
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int p_ssize; /* sample size */
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/* capture */
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int c_chmask; /* channel mask */
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int c_srate; /* rate in Hz */
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int c_ssize; /* sample size */
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int req_number; /* number of preallocated requests */
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};
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struct g_audio {
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struct usb_function func;
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struct usb_gadget *gadget;
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struct usb_ep *in_ep;
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struct usb_ep *out_ep;
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/* Max packet size for all in_ep possible speeds */
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unsigned int in_ep_maxpsize;
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/* Max packet size for all out_ep possible speeds */
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unsigned int out_ep_maxpsize;
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/* The ALSA Sound Card it represents on the USB-Client side */
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struct snd_uac_chip *uac;
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struct uac_params params;
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};
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static inline struct g_audio *func_to_g_audio(struct usb_function *f)
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{
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return container_of(f, struct g_audio, func);
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}
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static inline uint num_channels(uint chanmask)
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{
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uint num = 0;
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while (chanmask) {
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num += (chanmask & 1);
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chanmask >>= 1;
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}
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return num;
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}
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/*
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* g_audio_setup - initialize one virtual ALSA sound card
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* @g_audio: struct with filled params, in_ep_maxpsize, out_ep_maxpsize
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* @pcm_name: the id string for a PCM instance of this sound card
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* @card_name: name of this soundcard
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*
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* This sets up the single virtual ALSA sound card that may be exported by a
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* gadget driver using this framework.
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*
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* Context: may sleep
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*
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* Returns zero on success, or a negative error on failure.
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*/
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int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
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const char *card_name);
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void g_audio_cleanup(struct g_audio *g_audio);
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int u_audio_start_capture(struct g_audio *g_audio);
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void u_audio_stop_capture(struct g_audio *g_audio);
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int u_audio_start_playback(struct g_audio *g_audio);
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void u_audio_stop_playback(struct g_audio *g_audio);
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#endif /* __U_AUDIO_H */
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