Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 | // SPDX-License-Identifier: GPL-2.0-or-later /* * ALSA sequencer MIDI-through client * Copyright (c) 1999-2000 by Takashi Iwai <tiwai@suse.de> */ #include <linux/init.h> #include <linux/slab.h> #include <linux/module.h> #include <sound/core.h> #include "seq_clientmgr.h" #include <sound/initval.h> #include <sound/asoundef.h> /* Sequencer MIDI-through client This gives a simple midi-through client. All the normal input events are redirected to output port immediately. The routing can be done via aconnect program in alsa-utils. Each client has a static client number 14 (= SNDRV_SEQ_CLIENT_DUMMY). If you want to auto-load this module, you may add the following alias in your /etc/conf.modules file. alias snd-seq-client-14 snd-seq-dummy The module is loaded on demand for client 14, or /proc/asound/seq/ is accessed. If you don't need this module to be loaded, alias snd-seq-client-14 as "off". This will help modprobe. The number of ports to be created can be specified via the module parameter "ports". For example, to create four ports, add the following option in a configuration file under /etc/modprobe.d/: option snd-seq-dummy ports=4 The model option "duplex=1" enables duplex operation to the port. In duplex mode, a pair of ports are created instead of single port, and events are tunneled between pair-ports. For example, input to port A is sent to output port of another port B and vice versa. In duplex mode, each port has DUPLEX capability. */ MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>"); MODULE_DESCRIPTION("ALSA sequencer MIDI-through client"); MODULE_LICENSE("GPL"); MODULE_ALIAS("snd-seq-client-" __stringify(SNDRV_SEQ_CLIENT_DUMMY)); static int ports = 1; static bool duplex; module_param(ports, int, 0444); MODULE_PARM_DESC(ports, "number of ports to be created"); module_param(duplex, bool, 0444); MODULE_PARM_DESC(duplex, "create DUPLEX ports"); struct snd_seq_dummy_port { int client; int port; int duplex; int connect; }; static int my_client = -1; /* * event input callback - just redirect events to subscribers */ static int dummy_input(struct snd_seq_event *ev, int direct, void *private_data, int atomic, int hop) { struct snd_seq_dummy_port *p; struct snd_seq_event tmpev; p = private_data; if (ev->source.client == SNDRV_SEQ_CLIENT_SYSTEM || ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR) return 0; /* ignore system messages */ tmpev = *ev; if (p->duplex) tmpev.source.port = p->connect; else tmpev.source.port = p->port; tmpev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS; return snd_seq_kernel_client_dispatch(p->client, &tmpev, atomic, hop); } /* * free_private callback */ static void dummy_free(void *private_data) { kfree(private_data); } /* * create a port */ static struct snd_seq_dummy_port __init * create_port(int idx, int type) { struct snd_seq_port_info pinfo; struct snd_seq_port_callback pcb; struct snd_seq_dummy_port *rec; rec = kzalloc(sizeof(*rec), GFP_KERNEL); if (!rec) return NULL; rec->client = my_client; rec->duplex = duplex; rec->connect = 0; memset(&pinfo, 0, sizeof(pinfo)); pinfo.addr.client = my_client; if (duplex) sprintf(pinfo.name, "Midi Through Port-%d:%c", idx, (type ? 'B' : 'A')); else sprintf(pinfo.name, "Midi Through Port-%d", idx); pinfo.capability = SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ; pinfo.capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE; if (duplex) pinfo.capability |= SNDRV_SEQ_PORT_CAP_DUPLEX; pinfo.type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC | SNDRV_SEQ_PORT_TYPE_SOFTWARE | SNDRV_SEQ_PORT_TYPE_PORT; memset(&pcb, 0, sizeof(pcb)); pcb.owner = THIS_MODULE; pcb.event_input = dummy_input; pcb.private_free = dummy_free; pcb.private_data = rec; pinfo.kernel = &pcb; if (snd_seq_kernel_client_ctl(my_client, SNDRV_SEQ_IOCTL_CREATE_PORT, &pinfo) < 0) { kfree(rec); return NULL; } rec->port = pinfo.addr.port; return rec; } /* * register client and create ports */ static int __init register_client(void) { struct snd_seq_dummy_port *rec1, *rec2; int i; if (ports < 1) { pr_err("ALSA: seq_dummy: invalid number of ports %d\n", ports); return -EINVAL; } /* create client */ my_client = snd_seq_create_kernel_client(NULL, SNDRV_SEQ_CLIENT_DUMMY, "Midi Through"); if (my_client < 0) return my_client; /* create ports */ for (i = 0; i < ports; i++) { rec1 = create_port(i, 0); if (rec1 == NULL) { snd_seq_delete_kernel_client(my_client); return -ENOMEM; } if (duplex) { rec2 = create_port(i, 1); if (rec2 == NULL) { snd_seq_delete_kernel_client(my_client); return -ENOMEM; } rec1->connect = rec2->port; rec2->connect = rec1->port; } } return 0; } /* * delete client if exists */ static void __exit delete_client(void) { if (my_client >= 0) snd_seq_delete_kernel_client(my_client); } /* * Init part */ static int __init alsa_seq_dummy_init(void) { return register_client(); } static void __exit alsa_seq_dummy_exit(void) { delete_client(); } module_init(alsa_seq_dummy_init) module_exit(alsa_seq_dummy_exit) |