linux/sound/core/seq/seq_virmidi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Virtual Raw MIDI client on Sequencer
 *
 *  Copyright (c) 2000 by Takashi Iwai <[email protected]>,
 *                        Jaroslav Kysela <[email protected]>
 */

/*
 * Virtual Raw MIDI client
 *
 * The virtual rawmidi client is a sequencer client which associate
 * a rawmidi device file.  The created rawmidi device file can be
 * accessed as a normal raw midi, but its MIDI source and destination
 * are arbitrary.  For example, a user-client software synth connected
 * to this port can be used as a normal midi device as well.
 *
 * The virtual rawmidi device accepts also multiple opens.  Each file
 * has its own input buffer, so that no conflict would occur.  The drain
 * of input/output buffer acts only to the local buffer.
 *
 */

#include <linux/init.h>
#include <linux/wait.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/rawmidi.h>
#include <sound/info.h>
#include <sound/control.h>
#include <sound/minors.h>
#include <sound/seq_kernel.h>
#include <sound/seq_midi_event.h>
#include <sound/seq_virmidi.h>

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;

/*
 * initialize an event record
 */
static void snd_virmidi_init_event(struct snd_virmidi *vmidi,
				   struct snd_seq_event *ev)
{ … }

/*
 * decode input event and put to read buffer of each opened file
 */

/* callback for snd_seq_dump_var_event(), bridging to snd_rawmidi_receive() */
static int dump_to_rawmidi(void *ptr, void *buf, int count)
{ … }

static int snd_virmidi_dev_receive_event(struct snd_virmidi_dev *rdev,
					 struct snd_seq_event *ev,
					 bool atomic)
{ … }

/*
 * event handler of virmidi port
 */
static int snd_virmidi_event_input(struct snd_seq_event *ev, int direct,
				   void *private_data, int atomic, int hop)
{ … }

/*
 * trigger rawmidi stream for input
 */
static void snd_virmidi_input_trigger(struct snd_rawmidi_substream *substream, int up)
{ … }

/* process rawmidi bytes and send events;
 * we need no lock here for vmidi->event since it's handled only in this work
 */
static void snd_vmidi_output_work(struct work_struct *work)
{ … }

/*
 * trigger rawmidi stream for output
 */
static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up)
{ … }

/*
 * open rawmidi handle for input
 */
static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream)
{ … }

/*
 * open rawmidi handle for output
 */
static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream)
{ … }

/*
 * close rawmidi handle for input
 */
static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream)
{ … }

/*
 * close rawmidi handle for output
 */
static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream)
{ … }

/*
 * drain output work queue
 */
static void snd_virmidi_output_drain(struct snd_rawmidi_substream *substream)
{ … }

/*
 * subscribe callback - allow output to rawmidi device
 */
static int snd_virmidi_subscribe(void *private_data,
				 struct snd_seq_port_subscribe *info)
{ … }

/*
 * unsubscribe callback - disallow output to rawmidi device
 */
static int snd_virmidi_unsubscribe(void *private_data,
				   struct snd_seq_port_subscribe *info)
{ … }


/*
 * use callback - allow input to rawmidi device
 */
static int snd_virmidi_use(void *private_data,
			   struct snd_seq_port_subscribe *info)
{ … }

/*
 * unuse callback - disallow input to rawmidi device
 */
static int snd_virmidi_unuse(void *private_data,
			     struct snd_seq_port_subscribe *info)
{ … }


/*
 *  Register functions
 */

static const struct snd_rawmidi_ops snd_virmidi_input_ops = …;

static const struct snd_rawmidi_ops snd_virmidi_output_ops = …;

/*
 * create a sequencer client and a port
 */
static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev)
{ … }


/*
 * release the sequencer client
 */
static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev)
{ … }

/*
 * register the device
 */
static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi)
{ … }


/*
 * unregister the device
 */
static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi)
{ … }

/*
 *
 */
static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = …;

/*
 * free device
 */
static void snd_virmidi_free(struct snd_rawmidi *rmidi)
{ … }

/*
 * create a new device
 *
 */
/* exported */
int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi)
{ … }
EXPORT_SYMBOL(…);