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// SPDX-License-Identifier: GPL-2.0
/*
 * AVIRT - ALSA Virtual Soundcard
 *
 * Copyright (c) 2010-2018 Fiberdyne Systems Pty Ltd
 *
 * avirt.h - AVIRT system-level header
 */

#ifndef __SOUND_AVIRT_H
#define __SOUND_AVIRT_H

#include <sound/core.h>
#include <sound/pcm.h>
#include <linux/configfs.h>

#define MAX_STREAMS 16
#define MAX_NAME_LEN 80

#define DINFO(logname, fmt, args...)                                           \
	snd_printk(KERN_INFO "AVIRT: %s: " fmt "\n", logname, ##args)

#define DERROR(logname, fmt, args...)                                          \
	snd_printk(KERN_ERR "AVIRT: %s: " fmt "\n", logname, ##args)

#define DDEBUG(logname, fmt, args...)                                          \
	snd_printk(KERN_DEBUG "AVIRT: %s: " fmt "\n", logname, ##args)

struct snd_avirt_stream_array; /* Forward declaration */

/**
 * AVIRT Audio Path configure function type
 * Each Audio Path registers this at snd_avirt_audiopath_register time.
 * It is then called by the core once AVIRT has been configured
 */
typedef int (*snd_avirt_audiopath_configure)(
	struct snd_card *card, struct snd_avirt_stream_array *stream_array);

typedef void (*snd_avirt_pcm_exttrigger)(void);

/**
 * ALSA copy_kernel function type
 * A standard PCM operation from ALSA. This is used in AVIRT to copy PCM data
 * between Audio Paths, along given routes.
 */
typedef int (*snd_pcm_copy_kernel)(struct snd_pcm_substream *substream,
				   int channel, unsigned long pos, void *buf,
				   unsigned long bytes);

/*
 * AVIRT route source/sink enumeration types
 */
typedef enum snd_avirt_route_endpoint_t {
	SND_AVIRT_ROUTE_SOURCE,
	SND_AVIRT_ROUTE_SINK,
} snd_avirt_route_endpoint;

/**
 * Audio routing
 */
struct snd_avirt_route {
	char uid[MAX_NAME_LEN]; /* Unique identifier */
	unsigned int channels; /* Route stream channel count */
	unsigned int direction; /* Route stream direction */
	struct snd_avirt_audiopath *endpoint_ap[2]; /* Source/sink */
	struct snd_avirt_stream *endpoint_stream[2]; /* Router PCM */
	struct config_item item; /* configfs item reference */
};

/**
 * AVIRT Audio Path info
 */
typedef struct snd_avirt_audiopath snd_avirt_audiopath;
struct snd_avirt_audiopath {
	const char *uid; /* Unique identifier */
	const char *name; /* Pretty name */
	unsigned int version[3]; /* Version - Major.Minor.Ext */
	const struct snd_pcm_hardware *hw; /* ALSA PCM HW conf */
	const struct snd_pcm_ops *pcm_playback_ops; /* ALSA PCM playback ops */
	const struct snd_pcm_ops *pcm_capture_ops; /* ALSA PCM capture ops */
	snd_avirt_audiopath_configure configure; /* Config callback function */
	snd_avirt_pcm_exttrigger pcm_exttrigger; /* External trigger callback */
	void *context;
};

/**
 * Audio stream configuration
 */
struct snd_avirt_stream {
	char name[MAX_NAME_LEN]; /* Stream name */
	char map[MAX_NAME_LEN]; /* Stream Audio Path mapping */
	unsigned int channels; /* Stream channel count */
	unsigned int device; /* Stream PCM device no. */
	unsigned int direction; /* Stream direction */
	bool internal; /* Stream is internal only? */
	struct snd_pcm *pcm; /* ALSA PCM  */
	struct snd_pcm_ops *pcm_ops; /* ALSA PCM ops */
	struct snd_avirt_route *route; /* Associated route, if any */
	struct config_item item; /* configfs item reference */
};

/**
 * Audio stream group
 */
struct snd_avirt_stream_array {
	struct snd_avirt_stream *streams[MAX_STREAMS];
	int count;
};

/**
 * snd_avirt_private_free - free Audio Path private data from function prototype
 * @pcm: The PCM object
 */
typedef void (*snd_avirt_ap_private_free)(struct snd_pcm *pcm);
/**
 * Private Data Expansion
 */
struct snd_avirt_private_data {
	/* Initial Audio Path in the route */
	struct snd_avirt_audiopath *audiopath;
	/* Private data for source/sink Audio Paths */
	void *ap_private_data[2];
	snd_avirt_ap_private_free ap_private_free;
};

/**
 * snd_avirt_audiopath_register - register Audio Path with AVIRT
 * @audiopath: Audio Path to be registered
 * @return: 0 on success or error code otherwise
 */
int snd_avirt_audiopath_register(struct snd_avirt_audiopath *audiopath);

/**
 * snd_avirt_audiopath_deregister - deregister Audio Path with AVIRT
 * @audiopath: Audio Path to be deregistered
 * @return: 0 on success or error code otherwise
 */
int snd_avirt_audiopath_deregister(struct snd_avirt_audiopath *audiopath);

/**
 * snd_avirt_audiopath_get - get Audio Path by it's UID
 * @uid: The Audio Path UID to get
 * @return: The Audio Path if it exists, NULL otherwise.
 */
struct snd_avirt_audiopath *snd_avirt_audiopath_get(const char *uid);

/*
 * snd_avirt_audiopath_set_private_data - set PCM private data for an Audio Path
 * @ap: The Audio Path whose private data to set.
 * @pcm: The PCM where the private data is stored.
 * @ap_private_data: The value to set to the private data.
 * @return: 0 on success, -1 on failure.
 */
int snd_avirt_audiopath_set_private_data(struct snd_avirt_audiopath *ap,
					 struct snd_pcm *pcm,
					 void *ap_private_data);

/*
 * snd_avirt_audiopath_get_private_data - get PCM private data for an Audio Path
 * @ap: The Audio Path whose private data to get.
 * @pcm: The PCM where the private data is stored.
 * @return: The value assigned to the private data.
 */
void *snd_avirt_audiopath_get_private_data(struct snd_avirt_audiopath *ap,
					   struct snd_pcm *pcm);

/**
 * snd_avirt_route_endpoint_copy - get endpoint copy function for a given
 *                                 Audio Path's source/sink.
 * @ap: The Audio Path whose endpoint copy function to find.
 * @endpoint: The endpoint (SND_AVIRT_ROUTE_SOURCE or SND_AVIRT_ROUTE_SINK).
 * @return: A snd_pcm_copy_kernel function pointer that can be used to either:
 *          1. Source PCM data into the Audio Path, or,
 *          2. Sink PCM data out of the Audio Path.
 *          If no Audio Path endpoint is routed for 'endpoint', NULL is returned.
 */
snd_pcm_copy_kernel
snd_avirt_route_endpoint_copy(struct snd_pcm_substream *substream,
			      snd_avirt_route_endpoint endpoint);

/**
 * snd_avirt_route_endpoint_trigger - Trigger an Audio Path's endpoint
 *                                    (sink/source).
 * @uid: The Audio Path whose endpoint trigger function to call.
 * @endpoint: The endpoint (SND_AVIRT_ROUTE_SOURCE or SND_AVIRT_ROUTE_SINK).
 * @return: 0 on success or -1 on failure.
 */
int snd_avirt_route_endpoint_trigger(struct snd_pcm_substream *substream,
				     snd_avirt_route_endpoint endpoint);

#endif // __SOUND_AVIRT_H