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