933a2efc59
The ops structure has complex locking rules, where not all ops are equal, some are subordinate on others for some complex sound cards. This requires for lockdep checking that each individual reg_mutex is considered in separation for its locking rules. Has no effect on non-lockdep kernels. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Takashi Iwai <tiwai@suse.de> Cc: Jaroslav Kysela <perex@suse.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
594 lines
14 KiB
C
594 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 <sound/driver.h>
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#include <linux/init.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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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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/* registred 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 snd_seq_device_dev_unregister(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 list_head *head;
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mutex_lock(&ops_mutex);
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list_for_each(head, &opslist) {
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struct ops_list *ops = list_entry(head, struct ops_list, 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_KMOD
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/* avoid auto-loading during module_init() */
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static int snd_seq_in_init;
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void snd_seq_autoload_lock(void)
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{
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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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snd_seq_in_init--;
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}
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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_KMOD
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struct list_head *head;
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/* Calling request_module during module_init()
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* may cause blocking.
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*/
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if (snd_seq_in_init)
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return;
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if (! current->fs->root)
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return;
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mutex_lock(&ops_mutex);
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list_for_each(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->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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#endif
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}
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/*
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* register a sequencer device
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* card = card info (NULL allowed)
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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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.dev_unregister = snd_seq_device_dev_unregister
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};
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if (result)
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*result = NULL;
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snd_assert(id != NULL, 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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unlock_driver(ops);
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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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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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snd_assert(dev != NULL, 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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* unregister the existing device
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*/
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static int snd_seq_device_dev_unregister(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 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 list_head *head;
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struct ops_list *ops;
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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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snd_seq_autoload_lock();
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ops = find_driver(id, 1);
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if (ops == NULL) {
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snd_seq_autoload_unlock();
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return -ENOMEM;
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}
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if (ops->driver & DRIVER_LOADED) {
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snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id);
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unlock_driver(ops);
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snd_seq_autoload_unlock();
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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(head, &ops->dev_list) {
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struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, 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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snd_seq_autoload_unlock();
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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 = kmalloc(sizeof(*ops), GFP_KERNEL);
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if (ops == NULL)
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return ops;
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memset(ops, 0, sizeof(*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 list_head *head;
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struct ops_list *ops;
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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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snd_printk(KERN_ERR "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(head, &ops->dev_list) {
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struct snd_seq_device *dev = list_entry(head, struct snd_seq_device, 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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snd_printk(KERN_ERR "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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snd_printk(KERN_ERR "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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snd_printk(KERN_ERR "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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snd_printk(KERN_ERR "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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snd_printk(KERN_ERR "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 list_head *head;
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mutex_lock(&ops_mutex);
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list_for_each(head, &opslist) {
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struct ops_list *ops = list_entry(head, struct ops_list, 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;
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}
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}
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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)
|
|
{
|
|
remove_drivers();
|
|
#ifdef CONFIG_PROC_FS
|
|
snd_info_unregister(info_entry);
|
|
#endif
|
|
if (num_ops)
|
|
snd_printk(KERN_ERR "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_KMOD
|
|
EXPORT_SYMBOL(snd_seq_autoload_lock);
|
|
EXPORT_SYMBOL(snd_seq_autoload_unlock);
|
|
#endif
|