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 typedef struct snd_seq_dummy_port { 77 int client; 78 int port; 79 int duplex; 80 int connect; 81 } snd_seq_dummy_port_t; 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, snd_seq_port_subscribe_t *info) 92 { 93 snd_seq_dummy_port_t *p; 94 int i; 95 snd_seq_event_t 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(snd_seq_event_t *ev, int direct, void *private_data, int atomic, int hop) 120 { 121 snd_seq_dummy_port_t *p; 122 snd_seq_event_t 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 */ 140 static void 141 dummy_free(void *private_data) 142 { 143 snd_seq_dummy_port_t *p; 144 145 p = private_data; 146 kfree(p); 147 } 148 149 /* 150 * create a port 151 */ 152 static snd_seq_dummy_port_t __init * 153 create_port(int idx, int type) 154 { 155 snd_seq_port_info_t pinfo; 156 snd_seq_port_callback_t pcb; 157 snd_seq_dummy_port_t *rec; 158 159 if ((rec = kcalloc(1, sizeof(*rec), GFP_KERNEL)) == NULL) 160 return NULL; 161 162 rec->client = my_client; 163 rec->duplex = duplex; 164 rec->connect = 0; 165 memset(&pinfo, 0, sizeof(pinfo)); 166 pinfo.addr.client = my_client; 167 if (duplex) 168 sprintf(pinfo.name, "Midi Through Port-%d:%c", idx, 169 (type ? 'B' : 'A')); 170 else 171 sprintf(pinfo.name, "Midi Through Port-%d", idx); 172 pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ; 173 pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE; 174 if (duplex) 175 pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX; 176 pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC; 177 memset(&pcb, 0, sizeof(pcb)); 178 pcb.owner = THIS_MODULE; 179 pcb.unuse = dummy_unuse; 180 pcb.event_input = dummy_input; 181 pcb.private_free = dummy_free; 182 pcb.private_data = rec; 183 pinfo.kernel = &pcb; 184 if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) { 185 kfree(rec); 186 return NULL; 187 } 188 rec->port = pinfo.addr.port; 189 return rec; 190 } 191 192 /* 193 * register client and create ports 194 */ 195 static int __init 196 register_client(void) 197 { 198 snd_seq_client_callback_t cb; 199 snd_seq_client_info_t cinfo; 200 snd_seq_dummy_port_t *rec1, *rec2; 201 int i; 202 203 if (ports < 1) { 204 snd_printk(KERN_ERR "invalid number of ports %d\n", ports); 205 return -EINVAL; 206 } 207 208 /* create client */ 209 memset(&cb, 0, sizeof(cb)); 210 cb.allow_input = 1; 211 cb.allow_output = 1; 212 my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY, &cb); 213 if (my_client < 0) 214 return my_client; 215 216 /* set client name */ 217 memset(&cinfo, 0, sizeof(cinfo)); 218 cinfo.client = my_client; 219 cinfo.type = KERNEL_CLIENT; 220 strcpy(cinfo.name, "Midi Through"); 221 snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_SET_CLIENT_INFO, &cinfo); 222 223 /* create ports */ 224 for (i = 0; i < ports; i++) { 225 rec1 = create_port(i, 0); 226 if (rec1 == NULL) { 227 snd_seq_delete_kernel_client(my_client); 228 return -ENOMEM; 229 } 230 if (duplex) { 231 rec2 = create_port(i, 1); 232 if (rec2 == NULL) { 233 snd_seq_delete_kernel_client(my_client); 234 return -ENOMEM; 235 } 236 rec1->connect = rec2->port; 237 rec2->connect = rec1->port; 238 } 239 } 240 241 return 0; 242 } 243 244 /* 245 * delete client if exists 246 */ 247 static void __exit 248 delete_client(void) 249 { 250 if (my_client >= 0) 251 snd_seq_delete_kernel_client(my_client); 252 } 253 254 /* 255 * Init part 256 */ 257 258 static int __init alsa_seq_dummy_init(void) 259 { 260 int err; 261 snd_seq_autoload_lock(); 262 err = register_client(); 263 snd_seq_autoload_unlock(); 264 return err; 265 } 266 267 static void __exit alsa_seq_dummy_exit(void) 268 { 269 delete_client(); 270 } 271 272 module_init(alsa_seq_dummy_init) 273 module_exit(alsa_seq_dummy_exit) 274