cregit-Linux how code gets into the kernel

Release 4.11 sound/core/seq/seq_dummy.c

Directory: sound/core/seq
/*
 * ALSA sequencer MIDI-through client
 * Copyright (c) 1999-2000 by Takashi Iwai <tiwai@suse.de>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/core.h>
#include "seq_clientmgr.h"
#include <sound/initval.h>
#include <sound/asoundef.h>

/*

  Sequencer MIDI-through client

  This gives a simple midi-through client.  All the normal input events
  are redirected to output port immediately.
  The routing can be done via aconnect program in alsa-utils.

  Each client has a static client number 62 (= SNDRV_SEQ_CLIENT_DUMMY).
  If you want to auto-load this module, you may add the following alias
  in your /etc/conf.modules file.

        alias snd-seq-client-62  snd-seq-dummy

  The module is loaded on demand for client 62, or /proc/asound/seq/
  is accessed.  If you don't need this module to be loaded, alias
  snd-seq-client-62 as "off".  This will help modprobe.

  The number of ports to be created can be specified via the module
  parameter "ports".  For example, to create four ports, add the
  following option in a configuration file under /etc/modprobe.d/:

        option snd-seq-dummy ports=4

  The model option "duplex=1" enables duplex operation to the port.
  In duplex mode, a pair of ports are created instead of single port,
  and events are tunneled between pair-ports.  For example, input to
  port A is sent to output port of another port B and vice versa.
  In duplex mode, each port has DUPLEX capability.

 */


MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
MODULE_DESCRIPTION("ALSA sequencer MIDI-through client");
MODULE_LICENSE("GPL");
MODULE_ALIAS("snd-seq-client-" __stringify(SNDRV_SEQ_CLIENT_DUMMY));


static int ports = 1;

static bool duplex;

module_param(ports, int, 0444);
MODULE_PARM_DESC(ports, "number of ports to be created");
module_param(duplex, bool, 0444);
MODULE_PARM_DESC(duplex, "create DUPLEX ports");


struct snd_seq_dummy_port {
	
int client;
	
int port;
	
int duplex;
	
int connect;
};


static int my_client = -1;

/*
 * event input callback - just redirect events to subscribers
 */

static int dummy_input(struct snd_seq_event *ev, int direct, void *private_data, int atomic, int hop) { struct snd_seq_dummy_port *p; struct snd_seq_event tmpev; p = private_data; if (ev->source.client == SNDRV_SEQ_CLIENT_SYSTEM || ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR) return 0; /* ignore system messages */ tmpev = *ev; if (p->duplex) tmpev.source.port = p->connect; else tmpev.source.port = p->port; tmpev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS; return snd_seq_kernel_client_dispatch(p->client, &tmpev, atomic, hop); }

Contributors

PersonTokensPropCommitsCommitProp
Jaroslav Kysela10694.64%375.00%
Takashi Iwai65.36%125.00%
Total112100.00%4100.00%

/* * free_private callback */
static void dummy_free(void *private_data) { kfree(private_data); }

Contributors

PersonTokensPropCommitsCommitProp
Jaroslav Kysela1493.33%266.67%
Jesper Juhl16.67%133.33%
Total15100.00%3100.00%

/* * create a port */
static struct snd_seq_dummy_port __init * create_port(int idx, int type) { struct snd_seq_port_info pinfo; struct snd_seq_port_callback pcb; struct snd_seq_dummy_port *rec; if ((rec = kzalloc(sizeof(*rec), GFP_KERNEL)) == NULL) return NULL; rec->client = my_client; rec->duplex = duplex; rec->connect = 0; memset(&pinfo, 0, sizeof(pinfo)); pinfo.addr.client = my_client; if (duplex) sprintf(pinfo.name, "Midi Through Port-%d:%c", idx, (type ? 'B' : 'A')); else sprintf(pinfo.name, "Midi Through Port-%d", idx); pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ; pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE; if (duplex) pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX; pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC | SNDRV_SEQ_PORT_TYPE_SOFTWARE | SNDRV_SEQ_PORT_TYPE_PORT; memset(&pcb, 0, sizeof(pcb)); pcb.owner = THIS_MODULE; pcb.event_input = dummy_input; pcb.private_free = dummy_free; pcb.private_data = rec; pinfo.kernel = &pcb; if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) { kfree(rec); return NULL; } rec->port = pinfo.addr.port; return rec; }

Contributors

PersonTokensPropCommitsCommitProp
Jaroslav Kysela22894.61%240.00%
Takashi Iwai93.73%240.00%
Clemens Ladisch41.66%120.00%
Total241100.00%5100.00%

/* * register client and create ports */
static int __init register_client(void) { struct snd_seq_dummy_port *rec1, *rec2; int i; if (ports < 1) { pr_err("ALSA: seq_dummy: invalid number of ports %d\n", ports); return -EINVAL; } /* create client */ my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY, "Midi Through"); if (my_client < 0) return my_client; /* create ports */ for (i = 0; i < ports; i++) { rec1 = create_port(i, 0); if (rec1 == NULL) { snd_seq_delete_kernel_client(my_client); return -ENOMEM; } if (duplex) { rec2 = create_port(i, 1); if (rec2 == NULL) { snd_seq_delete_kernel_client(my_client); return -ENOMEM; } rec1->connect = rec2->port; rec2->connect = rec1->port; } } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Jaroslav Kysela14796.08%125.00%
Takashi Iwai42.61%250.00%
Clemens Ladisch21.31%125.00%
Total153100.00%4100.00%

/* * delete client if exists */
static void __exit delete_client(void) { if (my_client >= 0) snd_seq_delete_kernel_client(my_client); }

Contributors

PersonTokensPropCommitsCommitProp
Jaroslav Kysela20100.00%1100.00%
Total20100.00%1100.00%

/* * Init part */
static int __init alsa_seq_dummy_init(void) { return register_client(); }

Contributors

PersonTokensPropCommitsCommitProp
Jaroslav Kysela1292.31%150.00%
Takashi Iwai17.69%150.00%
Total13100.00%2100.00%


static void __exit alsa_seq_dummy_exit(void) { delete_client(); }

Contributors

PersonTokensPropCommitsCommitProp
Jaroslav Kysela12100.00%1100.00%
Total12100.00%1100.00%

module_init(alsa_seq_dummy_init) module_exit(alsa_seq_dummy_exit)

Overall Contributors

PersonTokensPropCommitsCommitProp
Jaroslav Kysela66295.53%637.50%
Takashi Iwai213.03%425.00%
Clemens Ladisch60.87%212.50%
Jesper Juhl10.14%16.25%
Rusty Russell10.14%16.25%
Lucas De Marchi10.14%16.25%
Paul Gortmaker10.14%16.25%
Total693100.00%16100.00%
Directory: sound/core/seq
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