LXR linux/sound/core/seq/seq

   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 */
  60static int sysclient = -1;
  61
  62/* port id numbers for this client */
  63static int announce_port = -1;
  64
  65
  66
  67/* fill standard header data, source port & channel are filled in */
  68static 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 */
  92void 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 */
 103int 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 */
 114static 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 */
 120int __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 */
 164void __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}
 174