sound/core/seq/seq_system.c

   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/slab.h>
  24 #include <sound/core.h>
  25 #include "seq_system.h"
  26 #include "seq_timer.h"
  27 #include "seq_queue.h"
  28
  29 /* internal client that provide system services, access to timer etc. */
  30
  31 /*
  32  * Port "Timer"
  33  *      - send tempo /start/stop etc. events to this port to manipulate the
  34  *        queue's timer. The queue address is specified in
  35  *        data.queue.queue.
  36  *      - this port supports subscription. The received timer events are
  37  *        broadcasted to all subscribed clients. The modified tempo
  38  *        value is stored on data.queue.value.
  39  *        The modifier client/port is not send.
  40  *
  41  * Port "Announce"
  42  *      - does not receive message
  43  *      - supports supscription. For each client or port attaching to or
  44  *        detaching from the system an announcement is send to the subscribed
  45  *        clients.
  46  *
  47  * Idea: the subscription mechanism might also work handy for distributing
  48  * synchronisation and timing information. In this case we would ideally have
  49  * a list of subscribers for each type of sync (time, tick), for each timing
  50  * queue.
  51  *
  52  * NOTE: the queue to be started, stopped, etc. must be specified
  53  *       in data.queue.addr.queue field.  queue is used only for
  54  *       scheduling, and no longer referred as affected queue.
  55  *       They are used only for timer broadcast (see above).
  56  *                                                      -- iwai
  57  */
  58
  59
  60 /* client id of our system client */
  61 static int sysclient = -1;
  62
  63 /* port id numbers for this client */
  64 static int announce_port = -1;
  65
  66
  67
  68 /* fill standard header data, source port & channel are filled in */
  69 static int setheader(struct snd_seq_event * ev, int client, int port)
  70 {
  71         if (announce_port < 0)
  72                 return -ENODEV;
  73
  74         memset(ev, 0, sizeof(struct snd_seq_event));
  75
  76         ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
  77         ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
  78
  79         ev->source.client = sysclient;
  80         ev->source.port = announce_port;
  81         ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
  82
  83         /* fill data */
  84         /*ev->data.addr.queue = SNDRV_SEQ_ADDRESS_UNKNOWN;*/
  85         ev->data.addr.client = client;
  86         ev->data.addr.port = port;
  87
  88         return 0;
  89 }
  90
  91
  92 /* entry points for broadcasting system events */
  93 void snd_seq_system_broadcast(int client, int port, int type)
  94 {
  95         struct snd_seq_event ev;
  96
  97         if (setheader(&ev, client, port) < 0)
  98                 return;
  99         ev.type = type;
 100         snd_seq_kernel_client_dispatch(sysclient, &ev, 0, 0);
 101 }
 102
 103 /* entry points for broadcasting system events */
 104 int snd_seq_system_notify(int client, int port, struct snd_seq_event *ev)
 105 {
 106         ev->flags = SNDRV_SEQ_EVENT_LENGTH_FIXED;
 107         ev->source.client = sysclient;
 108         ev->source.port = announce_port;
 109         ev->dest.client = client;
 110         ev->dest.port = port;
 111         return snd_seq_kernel_client_dispatch(sysclient, ev, 0, 0);
 112 }
 113
 114 /* call-back handler for timer events */
 115 static int event_input_timer(struct snd_seq_event * ev, int direct, void *private_data, int atomic, int hop)
 116 {
 117         return snd_seq_control_queue(ev, atomic, hop);
 118 }
 119
 120 /* register our internal client */
 121 int __init snd_seq_system_client_init(void)
 122 {
 123         struct snd_seq_port_callback pcallbacks;
 124         struct snd_seq_port_info *port;
 125
 126         port = kzalloc(sizeof(*port), GFP_KERNEL);
 127         if (!port)
 128                 return -ENOMEM;
 129
 130         memset(&pcallbacks, 0, sizeof(pcallbacks));
 131         pcallbacks.owner = THIS_MODULE;
 132         pcallbacks.event_input = event_input_timer;
 133
 134         /* register client */
 135         sysclient = snd_seq_create_kernel_client(NULL, 0, "System");
 136
 137         /* register timer */
 138         strcpy(port->name, "Timer");
 139         port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* accept queue control */
 140         port->capability |= SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast */
 141         port->kernel = &pcallbacks;
 142         port->type = 0;
 143         port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
 144         port->addr.client = sysclient;
 145         port->addr.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
 146         snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, port);
 147
 148         /* register announcement port */
 149         strcpy(port->name, "Announce");
 150         port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */
 151         port->kernel = NULL;
 152         port->type = 0;
 153         port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
 154         port->addr.client = sysclient;
 155         port->addr.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
 156         snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT, port);
 157         announce_port = port->addr.port;
 158
 159         kfree(port);
 160         return 0;
 161 }
 162
 163
 164 /* unregister our internal client */
 165 void __exit snd_seq_system_client_done(void)
 166 {
 167         int oldsysclient = sysclient;
 168
 169         if (oldsysclient >= 0) {
 170                 sysclient = -1;
 171                 announce_port = -1;
 172                 snd_seq_delete_kernel_client(oldsysclient);
 173         }
 174 }