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 kfree(private_data); 144 } 145 146 /* 147 * create a port 148 */ 149 static snd_seq_dummy_port_t __init * 150 create_port(int idx, int type) 151 { 152 snd_seq_port_info_t pinfo; 153 snd_seq_port_callback_t pcb; 154 snd_seq_dummy_port_t *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 memset(&pcb, 0, sizeof(pcb)); 175 pcb.owner = THIS_MODULE; 176 pcb.unuse = dummy_unuse; 177 pcb.event_input = dummy_input; 178 pcb.private_free = dummy_free; 179 pcb.private_data = rec; 180 pinfo.kernel = &pcb; 181 if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) { 182 kfree(rec); 183 return NULL; 184 } 185 rec->port = pinfo.addr.port; 186 return rec; 187 } 188 189 /* 190 * register client and create ports 191 */ 192 static int __init 193 register_client(void) 194 { 195 snd_seq_client_callback_t cb; 196 snd_seq_client_info_t cinfo; 197 snd_seq_dummy_port_t *rec1, *rec2; 198 int i; 199 200 if (ports < 1) { 201 snd_printk(KERN_ERR "invalid number of ports %d\n", ports); 202 return -EINVAL; 203 } 204 205 /* create client */ 206 memset(&cb, 0, sizeof(cb)); 207 cb.allow_input = 1; 208 cb.allow_output = 1; 209 my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY, &cb); 210 if (my_client < 0) 211 return my_client; 212 213 /* set client name */ 214 memset(&cinfo, 0, sizeof(cinfo)); 215 cinfo.client = my_client; 216 cinfo.type = KERNEL_CLIENT; 217 strcpy(cinfo.name, "Midi Through"); 218 snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_SET_CLIENT_INFO, &cinfo); 219 220 /* create ports */ 221 for (i = 0; i < ports; i++) { 222 rec1 = create_port(i, 0); 223 if (rec1 == NULL) { 224 snd_seq_delete_kernel_client(my_client); 225 return -ENOMEM; 226 } 227 if (duplex) { 228 rec2 = create_port(i, 1); 229 if (rec2 == NULL) { 230 snd_seq_delete_kernel_client(my_client); 231 return -ENOMEM; 232 } 233 rec1->connect = rec2->port; 234 rec2->connect = rec1->port; 235 } 236 } 237 238 return 0; 239 } 240 241 /* 242 * delete client if exists 243 */ 244 static void __exit 245 delete_client(void) 246 { 247 if (my_client >= 0) 248 snd_seq_delete_kernel_client(my_client); 249 } 250 251 /* 252 * Init part 253 */ 254 255 static int __init alsa_seq_dummy_init(void) 256 { 257 int err; 258 snd_seq_autoload_lock(); 259 err = register_client(); 260 snd_seq_autoload_unlock(); 261 return err; 262 } 263 264 static void __exit alsa_seq_dummy_exit(void) 265 { 266 delete_client(); 267 } 268 269 module_init(alsa_seq_dummy_init) 270 module_exit(alsa_seq_dummy_exit) 271