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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ALSA sequencer MIDI-through client
4 * Copyright (c) 1999-2000 by Takashi Iwai <tiwai@suse.de>
5 */
6
7#include <linux/init.h>
8#include <linux/slab.h>
9#include <linux/module.h>
10#include <sound/core.h>
11#include "seq_clientmgr.h"
12#include <sound/initval.h>
13#include <sound/asoundef.h>
14
15/*
16
17 Sequencer MIDI-through client
18
19 This gives a simple midi-through client. All the normal input events
20 are redirected to output port immediately.
21 The routing can be done via aconnect program in alsa-utils.
22
23 Each client has a static client number 62 (= SNDRV_SEQ_CLIENT_DUMMY).
24 If you want to auto-load this module, you may add the following alias
25 in your /etc/conf.modules file.
26
27 alias snd-seq-client-62 snd-seq-dummy
28
29 The module is loaded on demand for client 62, or /proc/asound/seq/
30 is accessed. If you don't need this module to be loaded, alias
31 snd-seq-client-62 as "off". This will help modprobe.
32
33 The number of ports to be created can be specified via the module
34 parameter "ports". For example, to create four ports, add the
35 following option in a configuration file under /etc/modprobe.d/:
36
37 option snd-seq-dummy ports=4
38
39 The model option "duplex=1" enables duplex operation to the port.
40 In duplex mode, a pair of ports are created instead of single port,
41 and events are tunneled between pair-ports. For example, input to
42 port A is sent to output port of another port B and vice versa.
43 In duplex mode, each port has DUPLEX capability.
44
45 */
46
47
48MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
49MODULE_DESCRIPTION("ALSA sequencer MIDI-through client");
50MODULE_LICENSE("GPL");
51MODULE_ALIAS("snd-seq-client-" __stringify(SNDRV_SEQ_CLIENT_DUMMY));
52
53static int ports = 1;
54static bool duplex;
55
56module_param(ports, int, 0444);
57MODULE_PARM_DESC(ports, "number of ports to be created");
58module_param(duplex, bool, 0444);
59MODULE_PARM_DESC(duplex, "create DUPLEX ports");
60
61struct snd_seq_dummy_port {
62 int client;
63 int port;
64 int duplex;
65 int connect;
66};
67
68static int my_client = -1;
69
70/*
71 * event input callback - just redirect events to subscribers
72 */
73static int
74dummy_input(struct snd_seq_event *ev, int direct, void *private_data,
75 int atomic, int hop)
76{
77 struct snd_seq_dummy_port *p;
78 struct snd_seq_event tmpev;
79
80 p = private_data;
81 if (ev->source.client == SNDRV_SEQ_CLIENT_SYSTEM ||
82 ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR)
83 return 0; /* ignore system messages */
84 tmpev = *ev;
85 if (p->duplex)
86 tmpev.source.port = p->connect;
87 else
88 tmpev.source.port = p->port;
89 tmpev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
90 return snd_seq_kernel_client_dispatch(p->client, &tmpev, atomic, hop);
91}
92
93/*
94 * free_private callback
95 */
96static void
97dummy_free(void *private_data)
98{
99 kfree(private_data);
100}
101
102/*
103 * create a port
104 */
105static struct snd_seq_dummy_port __init *
106create_port(int idx, int type)
107{
108 struct snd_seq_port_info pinfo;
109 struct snd_seq_port_callback pcb;
110 struct snd_seq_dummy_port *rec;
111
112 if ((rec = kzalloc(sizeof(*rec), GFP_KERNEL)) == NULL)
113 return NULL;
114
115 rec->client = my_client;
116 rec->duplex = duplex;
117 rec->connect = 0;
118 memset(&pinfo, 0, sizeof(pinfo));
119 pinfo.addr.client = my_client;
120 if (duplex)
121 sprintf(pinfo.name, "Midi Through Port-%d:%c", idx,
122 (type ? 'B' : 'A'));
123 else
124 sprintf(pinfo.name, "Midi Through Port-%d", idx);
125 pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
126 pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
127 if (duplex)
128 pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
129 pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
130 | SNDRV_SEQ_PORT_TYPE_SOFTWARE
131 | SNDRV_SEQ_PORT_TYPE_PORT;
132 memset(&pcb, 0, sizeof(pcb));
133 pcb.owner = THIS_MODULE;
134 pcb.event_input = dummy_input;
135 pcb.private_free = dummy_free;
136 pcb.private_data = rec;
137 pinfo.kernel = &pcb;
138 if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) {
139 kfree(rec);
140 return NULL;
141 }
142 rec->port = pinfo.addr.port;
143 return rec;
144}
145
146/*
147 * register client and create ports
148 */
149static int __init
150register_client(void)
151{
152 struct snd_seq_dummy_port *rec1, *rec2;
153 int i;
154
155 if (ports < 1) {
156 pr_err("ALSA: seq_dummy: invalid number of ports %d\n", ports);
157 return -EINVAL;
158 }
159
160 /* create client */
161 my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY,
162 "Midi Through");
163 if (my_client < 0)
164 return my_client;
165
166 /* create ports */
167 for (i = 0; i < ports; i++) {
168 rec1 = create_port(i, 0);
169 if (rec1 == NULL) {
170 snd_seq_delete_kernel_client(my_client);
171 return -ENOMEM;
172 }
173 if (duplex) {
174 rec2 = create_port(i, 1);
175 if (rec2 == NULL) {
176 snd_seq_delete_kernel_client(my_client);
177 return -ENOMEM;
178 }
179 rec1->connect = rec2->port;
180 rec2->connect = rec1->port;
181 }
182 }
183
184 return 0;
185}
186
187/*
188 * delete client if exists
189 */
190static void __exit
191delete_client(void)
192{
193 if (my_client >= 0)
194 snd_seq_delete_kernel_client(my_client);
195}
196
197/*
198 * Init part
199 */
200
201static int __init alsa_seq_dummy_init(void)
202{
203 return register_client();
204}
205
206static void __exit alsa_seq_dummy_exit(void)
207{
208 delete_client();
209}
210
211module_init(alsa_seq_dummy_init)
212module_exit(alsa_seq_dummy_exit)
1/*
2 * ALSA sequencer MIDI-through client
3 * Copyright (c) 1999-2000 by Takashi Iwai <tiwai@suse.de>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 */
20
21#include <linux/init.h>
22#include <linux/slab.h>
23#include <linux/module.h>
24#include <sound/core.h>
25#include "seq_clientmgr.h"
26#include <sound/initval.h>
27#include <sound/asoundef.h>
28
29/*
30
31 Sequencer MIDI-through client
32
33 This gives a simple midi-through client. All the normal input events
34 are redirected to output port immediately.
35 The routing can be done via aconnect program in alsa-utils.
36
37 Each client has a static client number 62 (= SNDRV_SEQ_CLIENT_DUMMY).
38 If you want to auto-load this module, you may add the following alias
39 in your /etc/conf.modules file.
40
41 alias snd-seq-client-62 snd-seq-dummy
42
43 The module is loaded on demand for client 62, or /proc/asound/seq/
44 is accessed. If you don't need this module to be loaded, alias
45 snd-seq-client-62 as "off". This will help modprobe.
46
47 The number of ports to be created can be specified via the module
48 parameter "ports". For example, to create four ports, add the
49 following option in a configuration file under /etc/modprobe.d/:
50
51 option snd-seq-dummy ports=4
52
53 The model option "duplex=1" enables duplex operation to the port.
54 In duplex mode, a pair of ports are created instead of single port,
55 and events are tunneled between pair-ports. For example, input to
56 port A is sent to output port of another port B and vice versa.
57 In duplex mode, each port has DUPLEX capability.
58
59 */
60
61
62MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
63MODULE_DESCRIPTION("ALSA sequencer MIDI-through client");
64MODULE_LICENSE("GPL");
65MODULE_ALIAS("snd-seq-client-" __stringify(SNDRV_SEQ_CLIENT_DUMMY));
66
67static int ports = 1;
68static bool duplex;
69
70module_param(ports, int, 0444);
71MODULE_PARM_DESC(ports, "number of ports to be created");
72module_param(duplex, bool, 0444);
73MODULE_PARM_DESC(duplex, "create DUPLEX ports");
74
75struct snd_seq_dummy_port {
76 int client;
77 int port;
78 int duplex;
79 int connect;
80};
81
82static int my_client = -1;
83
84/*
85 * unuse callback - send ALL_SOUNDS_OFF and RESET_CONTROLLERS events
86 * to subscribers.
87 * Note: this callback is called only after all subscribers are removed.
88 */
89static int
90dummy_unuse(void *private_data, struct snd_seq_port_subscribe *info)
91{
92 struct snd_seq_dummy_port *p;
93 int i;
94 struct snd_seq_event ev;
95
96 p = private_data;
97 memset(&ev, 0, sizeof(ev));
98 if (p->duplex)
99 ev.source.port = p->connect;
100 else
101 ev.source.port = p->port;
102 ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
103 ev.type = SNDRV_SEQ_EVENT_CONTROLLER;
104 for (i = 0; i < 16; i++) {
105 ev.data.control.channel = i;
106 ev.data.control.param = MIDI_CTL_ALL_SOUNDS_OFF;
107 snd_seq_kernel_client_dispatch(p->client, &ev, 0, 0);
108 ev.data.control.param = MIDI_CTL_RESET_CONTROLLERS;
109 snd_seq_kernel_client_dispatch(p->client, &ev, 0, 0);
110 }
111 return 0;
112}
113
114/*
115 * event input callback - just redirect events to subscribers
116 */
117static int
118dummy_input(struct snd_seq_event *ev, int direct, void *private_data,
119 int atomic, int hop)
120{
121 struct snd_seq_dummy_port *p;
122 struct snd_seq_event tmpev;
123
124 p = private_data;
125 if (ev->source.client == SNDRV_SEQ_CLIENT_SYSTEM ||
126 ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR)
127 return 0; /* ignore system messages */
128 tmpev = *ev;
129 if (p->duplex)
130 tmpev.source.port = p->connect;
131 else
132 tmpev.source.port = p->port;
133 tmpev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
134 return snd_seq_kernel_client_dispatch(p->client, &tmpev, atomic, hop);
135}
136
137/*
138 * free_private callback
139 */
140static void
141dummy_free(void *private_data)
142{
143 kfree(private_data);
144}
145
146/*
147 * create a port
148 */
149static struct snd_seq_dummy_port __init *
150create_port(int idx, int type)
151{
152 struct snd_seq_port_info pinfo;
153 struct snd_seq_port_callback pcb;
154 struct snd_seq_dummy_port *rec;
155
156 if ((rec = kzalloc(sizeof(*rec), GFP_KERNEL)) == NULL)
157 return NULL;
158
159 rec->client = my_client;
160 rec->duplex = duplex;
161 rec->connect = 0;
162 memset(&pinfo, 0, sizeof(pinfo));
163 pinfo.addr.client = my_client;
164 if (duplex)
165 sprintf(pinfo.name, "Midi Through Port-%d:%c", idx,
166 (type ? 'B' : 'A'));
167 else
168 sprintf(pinfo.name, "Midi Through Port-%d", idx);
169 pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
170 pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
171 if (duplex)
172 pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
173 pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
174 | SNDRV_SEQ_PORT_TYPE_SOFTWARE
175 | SNDRV_SEQ_PORT_TYPE_PORT;
176 memset(&pcb, 0, sizeof(pcb));
177 pcb.owner = THIS_MODULE;
178 pcb.unuse = dummy_unuse;
179 pcb.event_input = dummy_input;
180 pcb.private_free = dummy_free;
181 pcb.private_data = rec;
182 pinfo.kernel = &pcb;
183 if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) {
184 kfree(rec);
185 return NULL;
186 }
187 rec->port = pinfo.addr.port;
188 return rec;
189}
190
191/*
192 * register client and create ports
193 */
194static int __init
195register_client(void)
196{
197 struct snd_seq_dummy_port *rec1, *rec2;
198 int i;
199
200 if (ports < 1) {
201 pr_err("ALSA: seq_dummy: invalid number of ports %d\n", ports);
202 return -EINVAL;
203 }
204
205 /* create client */
206 my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY,
207 "Midi Through");
208 if (my_client < 0)
209 return my_client;
210
211 /* create ports */
212 for (i = 0; i < ports; i++) {
213 rec1 = create_port(i, 0);
214 if (rec1 == NULL) {
215 snd_seq_delete_kernel_client(my_client);
216 return -ENOMEM;
217 }
218 if (duplex) {
219 rec2 = create_port(i, 1);
220 if (rec2 == NULL) {
221 snd_seq_delete_kernel_client(my_client);
222 return -ENOMEM;
223 }
224 rec1->connect = rec2->port;
225 rec2->connect = rec1->port;
226 }
227 }
228
229 return 0;
230}
231
232/*
233 * delete client if exists
234 */
235static void __exit
236delete_client(void)
237{
238 if (my_client >= 0)
239 snd_seq_delete_kernel_client(my_client);
240}
241
242/*
243 * Init part
244 */
245
246static int __init alsa_seq_dummy_init(void)
247{
248 int err;
249 snd_seq_autoload_lock();
250 err = register_client();
251 snd_seq_autoload_unlock();
252 return err;
253}
254
255static void __exit alsa_seq_dummy_exit(void)
256{
257 delete_client();
258}
259
260module_init(alsa_seq_dummy_init)
261module_exit(alsa_seq_dummy_exit)