1 /* 2 * ALSA sequencer System services Client 3 * Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl> 4 * 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 * 20 */ 21 22 #include <linux/init.h> 23 #include <linux/export.h> 24 #include <linux/slab.h> 25 #include <sound/core.h> 26 #include "seq_system.h" 27 #include "seq_timer.h" 28 #include "seq_queue.h" 29 30 /* internal client that provide system services, access to timer etc. */ 31 32 /* 33 * Port "Timer" 34 * - send tempo /start/stop etc. events to this port to manipulate the 35 * queue's timer. The queue address is specified in 36 * data.queue.queue. 37 * - this port supports subscription. The received timer events are 38 * broadcasted to all subscribed clients. The modified tempo 39 * value is stored on data.queue.value. 40 * The modifier client/port is not send. 41 * 42 * Port "Announce" 43 * - does not receive message 44 * - supports supscription. For each client or port attaching to or 45 * detaching from the system an announcement is send to the subscribed 46 * clients. 47 * 48 * Idea: the subscription mechanism might also work handy for distributing 49 * synchronisation and timing information. In this case we would ideally have 50 * a list of subscribers for each type of sync (time, tick), for each timing 51 * queue. 52 * 53 * NOTE: the queue to be started, stopped, etc. must be specified 54 * in data.queue.addr.queue field. queue is used only for 55 * scheduling, and no longer referred as affected queue. 56 * They are used only for timer broadcast (see above). 57 * -- iwai 58 */ 59 60 61 /* client id of our system client */ 62 static int sysclient = -1; 63 64 /* port id numbers for this client */ 65 static int announce_port = -1; 66 67 68 69 /* fill standard header data, source port & channel are filled in */ 70 static int setheader(struct snd_seq_event * ev, int client, int port) 71 { 72 if (announce_port < 0) 73 return -ENODEV; 74 75 memset(ev, 0, sizeof(struct snd_seq_event)); 76 77 ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK; 78 ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED; 79 80 ev->source.client = sysclient; 81 ev->source.port = announce_port; 82 ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS; 83 84 /* fill data */ 85 /*ev->data.addr.queue = SNDRV_SEQ_ADDRESS_UNKNOWN;*/ 86 ev->data.addr.client = client; 87 ev->data.addr.port = port; 88 89 return 0; 90 } 91 92 93 /* entry points for broadcasting system events */ 94 void snd_seq_system_broadcast(int client, int port, int type) 95 { 96 struct snd_seq_event ev; 97 98 if (setheader(&ev, client, port) < 0) 99 return; 100 ev.type = type; 101 snd_seq_kernel_client_dispatch(sysclient, &ev, 0, 0); 102 } 103 104 /* entry points for broadcasting system events */ 105 int snd_seq_system_notify(int client, int port, struct snd_seq_event *ev) 106 { 107 ev->flags = SNDRV_SEQ_EVENT_LENGTH_FIXED; 108 ev->source.client = sysclient; 109 ev->source.port = announce_port; 110 ev->dest.client = client; 111 ev->dest.port = port; 112 return snd_seq_kernel_client_dispatch(sysclient, ev, 0, 0); 113 } 114 115 /* call-back handler for timer events */ 116 static int event_input_timer(struct snd_seq_event * ev, int direct, void *private_data, int atomic, int hop) 117 { 118 return snd_seq_control_queue(ev, atomic, hop); 119 } 120 121 /* register our internal client */ 122 int __init snd_seq_system_client_init(void) 123 { 124 struct snd_seq_port_callback pcallbacks; 125 struct snd_seq_port_info *port; 126 int err; 127 128 port = kzalloc(sizeof(*port), GFP_KERNEL); 129 if (!port) 130 return -ENOMEM; 131 132 memset(&pcallbacks, 0, sizeof(pcallbacks)); 133 pcallbacks.owner = THIS_MODULE; 134 pcallbacks.event_input = event_input_timer; 135 136 /* register client */ 137 sysclient = snd_seq_create_kernel_client(NULL, 0, "System"); 138 if (sysclient < 0) { 139 kfree(port); 140 return sysclient; 141 } 142 143 /* register timer */ 144 strcpy(port->name, "Timer"); 145 port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* accept queue control */ 146 port->capability |= SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast */ 147 port->kernel = &pcallbacks; 148 port->type = 0; 149 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT; 150 port->addr.client = sysclient; 151 port->addr.port = SNDRV_SEQ_PORT_SYSTEM_TIMER; 152 err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, 153 port); 154 if (err < 0) 155 goto error_port; 156 157 /* register announcement port */ 158 strcpy(port->name, "Announce"); 159 port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */ 160 port->kernel = NULL; 161 port->type = 0; 162 port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT; 163 port->addr.client = sysclient; 164 port->addr.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE; 165 err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, 166 port); 167 if (err < 0) 168 goto error_port; 169 announce_port = port->addr.port; 170 171 kfree(port); 172 return 0; 173 174 error_port: 175 snd_seq_system_client_done(); 176 kfree(port); 177 return err; 178 } 179 180 181 /* unregister our internal client */ 182 void snd_seq_system_client_done(void) 183 { 184 int oldsysclient = sysclient; 185 186 if (oldsysclient >= 0) { 187 sysclient = -1; 188 announce_port = -1; 189 snd_seq_delete_kernel_client(oldsysclient); 190 } 191 } 192