617 lines
14 KiB
C
617 lines
14 KiB
C
/*
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* ALSA sequencer device management
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* Copyright (c) 1999 by Takashi Iwai <tiwai@suse.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*
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*----------------------------------------------------------------
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*
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* This device handler separates the card driver module from sequencer
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* stuff (sequencer core, synth drivers, etc), so that user can avoid
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* to spend unnecessary resources e.g. if he needs only listening to
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* MP3s.
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*
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* The card (or lowlevel) driver creates a sequencer device entry
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* via snd_seq_device_new(). This is an entry pointer to communicate
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* with the sequencer device "driver", which is involved with the
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* actual part to communicate with the sequencer core.
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* Each sequencer device entry has an id string and the corresponding
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* driver with the same id is loaded when required. For example,
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* lowlevel codes to access emu8000 chip on sbawe card are included in
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* emu8000-synth module. To activate this module, the hardware
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* resources like i/o port are passed via snd_seq_device argument.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <sound/core.h>
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#include <sound/info.h>
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#include <sound/seq_device.h>
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#include <sound/seq_kernel.h>
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#include <sound/initval.h>
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#include <linux/kmod.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
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MODULE_DESCRIPTION("ALSA sequencer device management");
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MODULE_LICENSE("GPL");
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/* driver state */
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#define DRIVER_EMPTY 0
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#define DRIVER_LOADED (1<<0)
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#define DRIVER_REQUESTED (1<<1)
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#define DRIVER_LOCKED (1<<2)
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#define DRIVER_REQUESTING (1<<3)
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struct ops_list {
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char id[ID_LEN]; /* driver id */
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int driver; /* driver state */
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int used; /* reference counter */
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int argsize; /* argument size */
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/* operators */
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struct snd_seq_dev_ops ops;
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/* registered devices */
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struct list_head dev_list; /* list of devices */
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int num_devices; /* number of associated devices */
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int num_init_devices; /* number of initialized devices */
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struct mutex reg_mutex;
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struct list_head list; /* next driver */
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};
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static LIST_HEAD(opslist);
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static int num_ops;
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static DEFINE_MUTEX(ops_mutex);
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#ifdef CONFIG_PROC_FS
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static struct snd_info_entry *info_entry;
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#endif
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/*
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* prototypes
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*/
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static int snd_seq_device_free(struct snd_seq_device *dev);
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static int snd_seq_device_dev_free(struct snd_device *device);
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static int snd_seq_device_dev_register(struct snd_device *device);
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static int snd_seq_device_dev_disconnect(struct snd_device *device);
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static int init_device(struct snd_seq_device *dev, struct ops_list *ops);
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static int free_device(struct snd_seq_device *dev, struct ops_list *ops);
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static struct ops_list *find_driver(char *id, int create_if_empty);
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static struct ops_list *create_driver(char *id);
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static void unlock_driver(struct ops_list *ops);
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static void remove_drivers(void);
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/*
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* show all drivers and their status
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*/
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#ifdef CONFIG_PROC_FS
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static void snd_seq_device_info(struct snd_info_entry *entry,
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struct snd_info_buffer *buffer)
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{
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struct ops_list *ops;
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mutex_lock(&ops_mutex);
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list_for_each_entry(ops, &opslist, list) {
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snd_iprintf(buffer, "snd-%s%s%s%s,%d\n",
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ops->id,
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ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""),
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ops->driver & DRIVER_REQUESTED ? ",requested" : "",
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ops->driver & DRIVER_LOCKED ? ",locked" : "",
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ops->num_devices);
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}
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mutex_unlock(&ops_mutex);
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}
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#endif
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/*
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* load all registered drivers (called from seq_clientmgr.c)
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*/
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#ifdef CONFIG_MODULES
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/* avoid auto-loading during module_init() */
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static atomic_t snd_seq_in_init = ATOMIC_INIT(1); /* blocked as default */
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void snd_seq_autoload_lock(void)
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{
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atomic_inc(&snd_seq_in_init);
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}
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void snd_seq_autoload_unlock(void)
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{
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atomic_dec(&snd_seq_in_init);
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}
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static void autoload_drivers(void)
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{
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/* avoid reentrance */
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if (atomic_inc_return(&snd_seq_in_init) == 1) {
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struct ops_list *ops;
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mutex_lock(&ops_mutex);
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list_for_each_entry(ops, &opslist, list) {
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if ((ops->driver & DRIVER_REQUESTING) &&
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!(ops->driver & DRIVER_REQUESTED)) {
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ops->used++;
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mutex_unlock(&ops_mutex);
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ops->driver |= DRIVER_REQUESTED;
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request_module("snd-%s", ops->id);
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mutex_lock(&ops_mutex);
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ops->used--;
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}
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}
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mutex_unlock(&ops_mutex);
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}
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atomic_dec(&snd_seq_in_init);
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}
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static void call_autoload(struct work_struct *work)
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{
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autoload_drivers();
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}
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static DECLARE_WORK(autoload_work, call_autoload);
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static void try_autoload(struct ops_list *ops)
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{
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if (!ops->driver) {
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ops->driver |= DRIVER_REQUESTING;
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schedule_work(&autoload_work);
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}
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}
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static void queue_autoload_drivers(void)
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{
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struct ops_list *ops;
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mutex_lock(&ops_mutex);
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list_for_each_entry(ops, &opslist, list)
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try_autoload(ops);
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mutex_unlock(&ops_mutex);
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}
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void snd_seq_autoload_init(void)
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{
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atomic_dec(&snd_seq_in_init);
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#ifdef CONFIG_SND_SEQUENCER_MODULE
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/* initial autoload only when snd-seq is a module */
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queue_autoload_drivers();
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#endif
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}
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#else
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#define try_autoload(ops) /* NOP */
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#endif
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void snd_seq_device_load_drivers(void)
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{
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#ifdef CONFIG_MODULES
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queue_autoload_drivers();
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flush_work(&autoload_work);
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#endif
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}
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/*
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* register a sequencer device
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* card = card info
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* device = device number (if any)
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* id = id of driver
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* result = return pointer (NULL allowed if unnecessary)
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*/
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int snd_seq_device_new(struct snd_card *card, int device, char *id, int argsize,
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struct snd_seq_device **result)
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{
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struct snd_seq_device *dev;
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struct ops_list *ops;
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int err;
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static struct snd_device_ops dops = {
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.dev_free = snd_seq_device_dev_free,
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.dev_register = snd_seq_device_dev_register,
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.dev_disconnect = snd_seq_device_dev_disconnect,
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};
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if (result)
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*result = NULL;
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if (snd_BUG_ON(!id))
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return -EINVAL;
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ops = find_driver(id, 1);
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if (ops == NULL)
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return -ENOMEM;
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dev = kzalloc(sizeof(*dev)*2 + argsize, GFP_KERNEL);
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if (dev == NULL) {
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unlock_driver(ops);
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return -ENOMEM;
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}
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/* set up device info */
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dev->card = card;
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dev->device = device;
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strlcpy(dev->id, id, sizeof(dev->id));
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dev->argsize = argsize;
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dev->status = SNDRV_SEQ_DEVICE_FREE;
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/* add this device to the list */
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mutex_lock(&ops->reg_mutex);
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list_add_tail(&dev->list, &ops->dev_list);
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ops->num_devices++;
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mutex_unlock(&ops->reg_mutex);
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if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) {
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snd_seq_device_free(dev);
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return err;
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}
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try_autoload(ops);
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unlock_driver(ops);
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if (result)
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*result = dev;
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return 0;
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}
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/*
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* free the existing device
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*/
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static int snd_seq_device_free(struct snd_seq_device *dev)
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{
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struct ops_list *ops;
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if (snd_BUG_ON(!dev))
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return -EINVAL;
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ops = find_driver(dev->id, 0);
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if (ops == NULL)
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return -ENXIO;
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/* remove the device from the list */
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mutex_lock(&ops->reg_mutex);
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list_del(&dev->list);
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ops->num_devices--;
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mutex_unlock(&ops->reg_mutex);
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free_device(dev, ops);
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if (dev->private_free)
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dev->private_free(dev);
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kfree(dev);
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unlock_driver(ops);
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return 0;
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}
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static int snd_seq_device_dev_free(struct snd_device *device)
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{
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struct snd_seq_device *dev = device->device_data;
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return snd_seq_device_free(dev);
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}
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/*
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* register the device
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*/
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static int snd_seq_device_dev_register(struct snd_device *device)
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{
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struct snd_seq_device *dev = device->device_data;
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struct ops_list *ops;
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ops = find_driver(dev->id, 0);
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if (ops == NULL)
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return -ENOENT;
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/* initialize this device if the corresponding driver was
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* already loaded
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*/
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if (ops->driver & DRIVER_LOADED)
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init_device(dev, ops);
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unlock_driver(ops);
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return 0;
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}
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/*
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* disconnect the device
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*/
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static int snd_seq_device_dev_disconnect(struct snd_device *device)
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{
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struct snd_seq_device *dev = device->device_data;
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struct ops_list *ops;
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ops = find_driver(dev->id, 0);
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if (ops == NULL)
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return -ENOENT;
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free_device(dev, ops);
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unlock_driver(ops);
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return 0;
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}
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/*
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* register device driver
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* id = driver id
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* entry = driver operators - duplicated to each instance
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*/
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int snd_seq_device_register_driver(char *id, struct snd_seq_dev_ops *entry,
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int argsize)
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{
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struct ops_list *ops;
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struct snd_seq_device *dev;
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if (id == NULL || entry == NULL ||
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entry->init_device == NULL || entry->free_device == NULL)
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return -EINVAL;
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ops = find_driver(id, 1);
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if (ops == NULL)
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return -ENOMEM;
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if (ops->driver & DRIVER_LOADED) {
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pr_warn("ALSA: seq: driver_register: driver '%s' already exists\n", id);
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unlock_driver(ops);
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return -EBUSY;
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}
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mutex_lock(&ops->reg_mutex);
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/* copy driver operators */
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ops->ops = *entry;
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ops->driver |= DRIVER_LOADED;
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ops->argsize = argsize;
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/* initialize existing devices if necessary */
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list_for_each_entry(dev, &ops->dev_list, list) {
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init_device(dev, ops);
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}
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mutex_unlock(&ops->reg_mutex);
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unlock_driver(ops);
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return 0;
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}
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/*
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* create driver record
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*/
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static struct ops_list * create_driver(char *id)
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{
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struct ops_list *ops;
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ops = kzalloc(sizeof(*ops), GFP_KERNEL);
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if (ops == NULL)
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return ops;
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/* set up driver entry */
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strlcpy(ops->id, id, sizeof(ops->id));
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mutex_init(&ops->reg_mutex);
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/*
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* The ->reg_mutex locking rules are per-driver, so we create
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* separate per-driver lock classes:
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*/
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lockdep_set_class(&ops->reg_mutex, (struct lock_class_key *)id);
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ops->driver = DRIVER_EMPTY;
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INIT_LIST_HEAD(&ops->dev_list);
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/* lock this instance */
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ops->used = 1;
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/* register driver entry */
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mutex_lock(&ops_mutex);
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list_add_tail(&ops->list, &opslist);
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num_ops++;
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mutex_unlock(&ops_mutex);
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return ops;
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}
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/*
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* unregister the specified driver
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*/
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int snd_seq_device_unregister_driver(char *id)
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{
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struct ops_list *ops;
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struct snd_seq_device *dev;
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ops = find_driver(id, 0);
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if (ops == NULL)
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return -ENXIO;
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if (! (ops->driver & DRIVER_LOADED) ||
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(ops->driver & DRIVER_LOCKED)) {
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pr_err("ALSA: seq: driver_unregister: cannot unload driver '%s': status=%x\n",
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id, ops->driver);
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unlock_driver(ops);
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return -EBUSY;
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}
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/* close and release all devices associated with this driver */
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mutex_lock(&ops->reg_mutex);
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ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */
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list_for_each_entry(dev, &ops->dev_list, list) {
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free_device(dev, ops);
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}
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ops->driver = 0;
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if (ops->num_init_devices > 0)
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pr_err("ALSA: seq: free_driver: init_devices > 0!! (%d)\n",
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ops->num_init_devices);
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mutex_unlock(&ops->reg_mutex);
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unlock_driver(ops);
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/* remove empty driver entries */
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remove_drivers();
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return 0;
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}
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/*
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* remove empty driver entries
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*/
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static void remove_drivers(void)
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{
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struct list_head *head;
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mutex_lock(&ops_mutex);
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head = opslist.next;
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while (head != &opslist) {
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struct ops_list *ops = list_entry(head, struct ops_list, list);
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if (! (ops->driver & DRIVER_LOADED) &&
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ops->used == 0 && ops->num_devices == 0) {
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head = head->next;
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list_del(&ops->list);
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kfree(ops);
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num_ops--;
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} else
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head = head->next;
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}
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mutex_unlock(&ops_mutex);
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}
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/*
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* initialize the device - call init_device operator
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*/
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static int init_device(struct snd_seq_device *dev, struct ops_list *ops)
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{
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if (! (ops->driver & DRIVER_LOADED))
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return 0; /* driver is not loaded yet */
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if (dev->status != SNDRV_SEQ_DEVICE_FREE)
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return 0; /* already initialized */
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if (ops->argsize != dev->argsize) {
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pr_err("ALSA: seq: incompatible device '%s' for plug-in '%s' (%d %d)\n",
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dev->name, ops->id, ops->argsize, dev->argsize);
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return -EINVAL;
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}
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if (ops->ops.init_device(dev) >= 0) {
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dev->status = SNDRV_SEQ_DEVICE_REGISTERED;
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ops->num_init_devices++;
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} else {
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pr_err("ALSA: seq: init_device failed: %s: %s\n",
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dev->name, dev->id);
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}
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return 0;
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}
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/*
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* release the device - call free_device operator
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*/
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static int free_device(struct snd_seq_device *dev, struct ops_list *ops)
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{
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int result;
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if (! (ops->driver & DRIVER_LOADED))
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return 0; /* driver is not loaded yet */
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if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED)
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return 0; /* not registered */
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if (ops->argsize != dev->argsize) {
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pr_err("ALSA: seq: incompatible device '%s' for plug-in '%s' (%d %d)\n",
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dev->name, ops->id, ops->argsize, dev->argsize);
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return -EINVAL;
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}
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if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) {
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dev->status = SNDRV_SEQ_DEVICE_FREE;
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dev->driver_data = NULL;
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ops->num_init_devices--;
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} else {
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pr_err("ALSA: seq: free_device failed: %s: %s\n",
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dev->name, dev->id);
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}
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return 0;
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}
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/*
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* find the matching driver with given id
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*/
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static struct ops_list * find_driver(char *id, int create_if_empty)
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{
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struct ops_list *ops;
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mutex_lock(&ops_mutex);
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list_for_each_entry(ops, &opslist, list) {
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if (strcmp(ops->id, id) == 0) {
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ops->used++;
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mutex_unlock(&ops_mutex);
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|
return ops;
|
|
}
|
|
}
|
|
mutex_unlock(&ops_mutex);
|
|
if (create_if_empty)
|
|
return create_driver(id);
|
|
return NULL;
|
|
}
|
|
|
|
static void unlock_driver(struct ops_list *ops)
|
|
{
|
|
mutex_lock(&ops_mutex);
|
|
ops->used--;
|
|
mutex_unlock(&ops_mutex);
|
|
}
|
|
|
|
|
|
/*
|
|
* module part
|
|
*/
|
|
|
|
static int __init alsa_seq_device_init(void)
|
|
{
|
|
#ifdef CONFIG_PROC_FS
|
|
info_entry = snd_info_create_module_entry(THIS_MODULE, "drivers",
|
|
snd_seq_root);
|
|
if (info_entry == NULL)
|
|
return -ENOMEM;
|
|
info_entry->content = SNDRV_INFO_CONTENT_TEXT;
|
|
info_entry->c.text.read = snd_seq_device_info;
|
|
if (snd_info_register(info_entry) < 0) {
|
|
snd_info_free_entry(info_entry);
|
|
return -ENOMEM;
|
|
}
|
|
#endif
|
|
return 0;
|
|
}
|
|
|
|
static void __exit alsa_seq_device_exit(void)
|
|
{
|
|
#ifdef CONFIG_MODULES
|
|
cancel_work_sync(&autoload_work);
|
|
#endif
|
|
remove_drivers();
|
|
#ifdef CONFIG_PROC_FS
|
|
snd_info_free_entry(info_entry);
|
|
#endif
|
|
if (num_ops)
|
|
pr_err("ALSA: seq: drivers not released (%d)\n", num_ops);
|
|
}
|
|
|
|
module_init(alsa_seq_device_init)
|
|
module_exit(alsa_seq_device_exit)
|
|
|
|
EXPORT_SYMBOL(snd_seq_device_load_drivers);
|
|
EXPORT_SYMBOL(snd_seq_device_new);
|
|
EXPORT_SYMBOL(snd_seq_device_register_driver);
|
|
EXPORT_SYMBOL(snd_seq_device_unregister_driver);
|
|
#ifdef CONFIG_MODULES
|
|
EXPORT_SYMBOL(snd_seq_autoload_init);
|
|
EXPORT_SYMBOL(snd_seq_autoload_lock);
|
|
EXPORT_SYMBOL(snd_seq_autoload_unlock);
|
|
#endif
|