linux/sound/core/seq/seq_system.c
Thomas Gleixner 1a59d1b8e0 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:35 -07:00

177 lines
4.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ALSA sequencer System services Client
* Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
*/
#include <linux/init.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <sound/core.h>
#include "seq_system.h"
#include "seq_timer.h"
#include "seq_queue.h"
/* internal client that provide system services, access to timer etc. */
/*
* Port "Timer"
* - send tempo /start/stop etc. events to this port to manipulate the
* queue's timer. The queue address is specified in
* data.queue.queue.
* - this port supports subscription. The received timer events are
* broadcasted to all subscribed clients. The modified tempo
* value is stored on data.queue.value.
* The modifier client/port is not send.
*
* Port "Announce"
* - does not receive message
* - supports supscription. For each client or port attaching to or
* detaching from the system an announcement is send to the subscribed
* clients.
*
* Idea: the subscription mechanism might also work handy for distributing
* synchronisation and timing information. In this case we would ideally have
* a list of subscribers for each type of sync (time, tick), for each timing
* queue.
*
* NOTE: the queue to be started, stopped, etc. must be specified
* in data.queue.addr.queue field. queue is used only for
* scheduling, and no longer referred as affected queue.
* They are used only for timer broadcast (see above).
* -- iwai
*/
/* client id of our system client */
static int sysclient = -1;
/* port id numbers for this client */
static int announce_port = -1;
/* fill standard header data, source port & channel are filled in */
static int setheader(struct snd_seq_event * ev, int client, int port)
{
if (announce_port < 0)
return -ENODEV;
memset(ev, 0, sizeof(struct snd_seq_event));
ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
ev->source.client = sysclient;
ev->source.port = announce_port;
ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
/* fill data */
/*ev->data.addr.queue = SNDRV_SEQ_ADDRESS_UNKNOWN;*/
ev->data.addr.client = client;
ev->data.addr.port = port;
return 0;
}
/* entry points for broadcasting system events */
void snd_seq_system_broadcast(int client, int port, int type)
{
struct snd_seq_event ev;
if (setheader(&ev, client, port) < 0)
return;
ev.type = type;
snd_seq_kernel_client_dispatch(sysclient, &ev, 0, 0);
}
/* entry points for broadcasting system events */
int snd_seq_system_notify(int client, int port, struct snd_seq_event *ev)
{
ev->flags = SNDRV_SEQ_EVENT_LENGTH_FIXED;
ev->source.client = sysclient;
ev->source.port = announce_port;
ev->dest.client = client;
ev->dest.port = port;
return snd_seq_kernel_client_dispatch(sysclient, ev, 0, 0);
}
/* call-back handler for timer events */
static int event_input_timer(struct snd_seq_event * ev, int direct, void *private_data, int atomic, int hop)
{
return snd_seq_control_queue(ev, atomic, hop);
}
/* register our internal client */
int __init snd_seq_system_client_init(void)
{
struct snd_seq_port_callback pcallbacks;
struct snd_seq_port_info *port;
int err;
port = kzalloc(sizeof(*port), GFP_KERNEL);
if (!port)
return -ENOMEM;
memset(&pcallbacks, 0, sizeof(pcallbacks));
pcallbacks.owner = THIS_MODULE;
pcallbacks.event_input = event_input_timer;
/* register client */
sysclient = snd_seq_create_kernel_client(NULL, 0, "System");
if (sysclient < 0) {
kfree(port);
return sysclient;
}
/* register timer */
strcpy(port->name, "Timer");
port->capability = SNDRV_SEQ_PORT_CAP_WRITE; /* accept queue control */
port->capability |= SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast */
port->kernel = &pcallbacks;
port->type = 0;
port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
port->addr.client = sysclient;
port->addr.port = SNDRV_SEQ_PORT_SYSTEM_TIMER;
err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT,
port);
if (err < 0)
goto error_port;
/* register announcement port */
strcpy(port->name, "Announce");
port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */
port->kernel = NULL;
port->type = 0;
port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
port->addr.client = sysclient;
port->addr.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
err = snd_seq_kernel_client_ctl(sysclient, SNDRV_SEQ_IOCTL_CREATE_PORT,
port);
if (err < 0)
goto error_port;
announce_port = port->addr.port;
kfree(port);
return 0;
error_port:
snd_seq_system_client_done();
kfree(port);
return err;
}
/* unregister our internal client */
void snd_seq_system_client_done(void)
{
int oldsysclient = sysclient;
if (oldsysclient >= 0) {
sysclient = -1;
announce_port = -1;
snd_seq_delete_kernel_client(oldsysclient);
}
}