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 <sound/driver.h>
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/moduleparam.h>
25 #include <sound/core.h>
26 #include "seq_clientmgr.h"
27 #include <sound/initval.h>
28 #include <sound/asoundef.h>
29
30 /*
31
32 Sequencer MIDI-through client
33
34 This gives a simple midi-through client. All the normal input events
35 are redirected to output port immediately.
36 The routing can be done via aconnect program in alsa-utils.
37
38 Each client has a static client number 62 (= SNDRV_SEQ_CLIENT_DUMMY).
39 If you want to auto-load this module, you may add the following alias
40 in your /etc/conf.modules file.
41
42 alias snd-seq-client-62 snd-seq-dummy
43
44 The module is loaded on demand for client 62, or /proc/asound/seq/
45 is accessed. If you don't need this module to be loaded, alias
46 snd-seq-client-62 as "off". This will help modprobe.
47
48 The number of ports to be created can be specified via the module
49 parameter "ports". For example, to create four ports, add the
50 following option in /etc/modprobe.conf:
51
52 option snd-seq-dummy ports=4
53
54 The modle option "duplex=1" enables duplex operation to the port.
55 In duplex mode, a pair of ports are created instead of single port,
56 and events are tunneled between pair-ports. For example, input to
57 port A is sent to output port of another port B and vice versa.
58 In duplex mode, each port has DUPLEX capability.
59
60 */
61
62
63 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
64 MODULE_DESCRIPTION("ALSA sequencer MIDI-through client");
65 MODULE_LICENSE("GPL");
66
67 static int ports = 1;
68 static int duplex = 0;
69
70 module_param(ports, int, 0444);
71 MODULE_PARM_DESC(ports, "number of ports to be created");
72 module_param(duplex, bool, 0444);
73 MODULE_PARM_DESC(duplex, "create DUPLEX ports");
74
75 typedef struct snd_seq_dummy_port {
76 int client;
77 int port;
78 int duplex;
79 int connect;
80 } snd_seq_dummy_port_t;
81
82 static 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 */
89 static int
90 dummy_unuse(void *private_data, snd_seq_port_subscribe_t *info)
91 {
92 snd_seq_dummy_port_t *p;
93 int i;
94 snd_seq_event_t 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 */
117 static int
118 dummy_input(snd_seq_event_t *ev, int direct, void *private_data, int atomic, int hop)
119 {
120 snd_seq_dummy_port_t *p;
121 snd_seq_event_t tmpev;
122
123 p = private_data;
124 if (ev->source.client == SNDRV_SEQ_CLIENT_SYSTEM ||
125 ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR)
126 return 0; /* ignore system messages */
127 tmpev = *ev;
128 if (p->duplex)
129 tmpev.source.port = p->connect;
130 else
131 tmpev.source.port = p->port;
132 tmpev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
133 return snd_seq_kernel_client_dispatch(p->client, &tmpev, atomic, hop);
134 }
135
136 /*
137 * free_private callback
138 */
139 static void
140 dummy_free(void *private_data)
141 {
142 snd_seq_dummy_port_t *p;
143
144 p = private_data;
145 kfree(p);
146 }
147
148 /*
149 * create a port
150 */
151 static snd_seq_dummy_port_t __init *
152 create_port(int idx, int type)
153 {
154 snd_seq_port_info_t pinfo;
155 snd_seq_port_callback_t pcb;
156 snd_seq_dummy_port_t *rec;
157
158 if ((rec = kcalloc(1, sizeof(*rec), GFP_KERNEL)) == NULL)
159 return NULL;
160
161 rec->client = my_client;
162 rec->duplex = duplex;
163 rec->connect = 0;
164 memset(&pinfo, 0, sizeof(pinfo));
165 pinfo.addr.client = my_client;
166 if (duplex)
167 sprintf(pinfo.name, "Midi Through Port-%d:%c", idx,
168 (type ? 'B' : 'A'));
169 else
170 sprintf(pinfo.name, "Midi Through Port-%d", idx);
171 pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
172 pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
173 if (duplex)
174 pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
175 pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC;
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 */
194 static int __init
195 register_client(void)
196 {
197 snd_seq_client_callback_t cb;
198 snd_seq_client_info_t cinfo;
199 snd_seq_dummy_port_t *rec1, *rec2;
200 int i;
201
202 if (ports < 1) {
203 snd_printk(KERN_ERR "invalid number of ports %d\n", ports);
204 return -EINVAL;
205 }
206
207 /* create client */
208 memset(&cb, 0, sizeof(cb));
209 cb.allow_input = 1;
210 cb.allow_output = 1;
211 my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY, &cb);
212 if (my_client < 0)
213 return my_client;
214
215 /* set client name */
216 memset(&cinfo, 0, sizeof(cinfo));
217 cinfo.client = my_client;
218 cinfo.type = KERNEL_CLIENT;
219 strcpy(cinfo.name, "Midi Through");
220 snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_SET_CLIENT_INFO, &cinfo);
221
222 /* create ports */
223 for (i = 0; i < ports; i++) {
224 rec1 = create_port(i, 0);
225 if (rec1 == NULL) {
226 snd_seq_delete_kernel_client(my_client);
227 return -ENOMEM;
228 }
229 if (duplex) {
230 rec2 = create_port(i, 1);
231 if (rec2 == NULL) {
232 snd_seq_delete_kernel_client(my_client);
233 return -ENOMEM;
234 }
235 rec1->connect = rec2->port;
236 rec2->connect = rec1->port;
237 }
238 }
239
240 return 0;
241 }
242
243 /*
244 * delete client if exists
245 */
246 static void __exit
247 delete_client(void)
248 {
249 if (my_client >= 0)
250 snd_seq_delete_kernel_client(my_client);
251 }
252
253 /*
254 * Init part
255 */
256
257 static int __init alsa_seq_dummy_init(void)
258 {
259 int err;
260 snd_seq_autoload_lock();
261 err = register_client();
262 snd_seq_autoload_unlock();
263 return err;
264 }
265
266 static void __exit alsa_seq_dummy_exit(void)
267 {
268 delete_client();
269 }
270
271 module_init(alsa_seq_dummy_init)
272 module_exit(alsa_seq_dummy_exit)
273
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