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 MODULE_ALIAS("snd-seq-client-" __stringify(SNDRV_SEQ_CLIENT_DUMMY)); 67 68 static int ports = 1; 69 static int duplex = 0; 70 71 module_param(ports, int, 0444); 72 MODULE_PARM_DESC(ports, "number of ports to be created"); 73 module_param(duplex, bool, 0444); 74 MODULE_PARM_DESC(duplex, "create DUPLEX ports"); 75 76 struct snd_seq_dummy_port { 77 int client; 78 int port; 79 int duplex; 80 int connect; 81 }; 82 83 static int my_client = -1; 84 85 /* 86 * unuse callback - send ALL_SOUNDS_OFF and RESET_CONTROLLERS events 87 * to subscribers. 88 * Note: this callback is called only after all subscribers are removed. 89 */ 90 static int 91 dummy_unuse(void *private_data, struct snd_seq_port_subscribe *info) 92 { 93 struct snd_seq_dummy_port *p; 94 int i; 95 struct snd_seq_event ev; 96 97 p = private_data; 98 memset(&ev, 0, sizeof(ev)); 99 if (p->duplex) 100 ev.source.port = p->connect; 101 else 102 ev.source.port = p->port; 103 ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS; 104 ev.type = SNDRV_SEQ_EVENT_CONTROLLER; 105 for (i = 0; i < 16; i++) { 106 ev.data.control.channel = i; 107 ev.data.control.param = MIDI_CTL_ALL_SOUNDS_OFF; 108 snd_seq_kernel_client_dispatch(p->client, &ev, 0, 0); 109 ev.data.control.param = MIDI_CTL_RESET_CONTROLLERS; 110 snd_seq_kernel_client_dispatch(p->client, &ev, 0, 0); 111 } 112 return 0; 113 } 114 115 /* 116 * event input callback - just redirect events to subscribers 117 */ 118 static int 119 dummy_input(struct snd_seq_event *ev, int direct, void *private_data, 120 int atomic, int hop) 121 { 122 struct snd_seq_dummy_port *p; 123 struct snd_seq_event tmpev; 124 125 p = private_data; 126 if (ev->source.client == SNDRV_SEQ_CLIENT_SYSTEM || 127 ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR) 128 return 0; /* ignore system messages */ 129 tmpev = *ev; 130 if (p->duplex) 131 tmpev.source.port = p->connect; 132 else 133 tmpev.source.port = p->port; 134 tmpev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS; 135 return snd_seq_kernel_client_dispatch(p->client, &tmpev, atomic, hop); 136 } 137 138 /* 139 * free_private callback 140 */ 141 static void 142 dummy_free(void *private_data) 143 { 144 kfree(private_data); 145 } 146 147 /* 148 * create a port 149 */ 150 static struct snd_seq_dummy_port __init * 151 create_port(int idx, int type) 152 { 153 struct snd_seq_port_info pinfo; 154 struct snd_seq_port_callback pcb; 155 struct snd_seq_dummy_port *rec; 156 157 if ((rec = kzalloc(sizeof(*rec), GFP_KERNEL)) == NULL) 158 return NULL; 159 160 rec->client = my_client; 161 rec->duplex = duplex; 162 rec->connect = 0; 163 memset(&pinfo, 0, sizeof(pinfo)); 164 pinfo.addr.client = my_client; 165 if (duplex) 166 sprintf(pinfo.name, "Midi Through Port-%d:%c", idx, 167 (type ? 'B' : 'A')); 168 else 169 sprintf(pinfo.name, "Midi Through Port-%d", idx); 170 pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ; 171 pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE; 172 if (duplex) 173 pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX; 174 pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC; 175 memset(&pcb, 0, sizeof(pcb)); 176 pcb.owner = THIS_MODULE; 177 pcb.unuse = dummy_unuse; 178 pcb.event_input = dummy_input; 179 pcb.private_free = dummy_free; 180 pcb.private_data = rec; 181 pinfo.kernel = &pcb; 182 if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) { 183 kfree(rec); 184 return NULL; 185 } 186 rec->port = pinfo.addr.port; 187 return rec; 188 } 189 190 /* 191 * register client and create ports 192 */ 193 static int __init 194 register_client(void) 195 { 196 struct snd_seq_dummy_port *rec1, *rec2; 197 int i; 198 199 if (ports < 1) { 200 snd_printk(KERN_ERR "invalid number of ports %d\n", ports); 201 return -EINVAL; 202 } 203 204 /* create client */ 205 my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY, 206 "Midi Through"); 207 if (my_client < 0) 208 return my_client; 209 210 /* create ports */ 211 for (i = 0; i < ports; i++) { 212 rec1 = create_port(i, 0); 213 if (rec1 == NULL) { 214 snd_seq_delete_kernel_client(my_client); 215 return -ENOMEM; 216 } 217 if (duplex) { 218 rec2 = create_port(i, 1); 219 if (rec2 == NULL) { 220 snd_seq_delete_kernel_client(my_client); 221 return -ENOMEM; 222 } 223 rec1->connect = rec2->port; 224 rec2->connect = rec1->port; 225 } 226 } 227 228 return 0; 229 } 230 231 /* 232 * delete client if exists 233 */ 234 static void __exit 235 delete_client(void) 236 { 237 if (my_client >= 0) 238 snd_seq_delete_kernel_client(my_client); 239 } 240 241 /* 242 * Init part 243 */ 244 245 static int __init alsa_seq_dummy_init(void) 246 { 247 int err; 248 snd_seq_autoload_lock(); 249 err = register_client(); 250 snd_seq_autoload_unlock(); 251 return err; 252 } 253 254 static void __exit alsa_seq_dummy_exit(void) 255 { 256 delete_client(); 257 } 258 259 module_init(alsa_seq_dummy_init) 260 module_exit(alsa_seq_dummy_exit) 261