diff options
Diffstat (limited to 'sound/core/seq/seq_device.c')
| -rw-r--r-- | sound/core/seq/seq_device.c | 575 |
1 files changed, 575 insertions, 0 deletions
diff --git a/sound/core/seq/seq_device.c b/sound/core/seq/seq_device.c new file mode 100644 index 000000000000..4d80f39612e8 --- /dev/null +++ b/sound/core/seq/seq_device.c @@ -0,0 +1,575 @@ +/* + * ALSA sequencer device management + * Copyright (c) 1999 by Takashi Iwai <tiwai@suse.de> + * + * 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 + * + * + *---------------------------------------------------------------- + * + * This device handler separates the card driver module from sequencer + * stuff (sequencer core, synth drivers, etc), so that user can avoid + * to spend unnecessary resources e.g. if he needs only listening to + * MP3s. + * + * The card (or lowlevel) driver creates a sequencer device entry + * via snd_seq_device_new(). This is an entry pointer to communicate + * with the sequencer device "driver", which is involved with the + * actual part to communicate with the sequencer core. + * Each sequencer device entry has an id string and the corresponding + * driver with the same id is loaded when required. For example, + * lowlevel codes to access emu8000 chip on sbawe card are included in + * emu8000-synth module. To activate this module, the hardware + * resources like i/o port are passed via snd_seq_device argument. + * + */ + +#include <sound/driver.h> +#include <linux/init.h> +#include <sound/core.h> +#include <sound/info.h> +#include <sound/seq_device.h> +#include <sound/seq_kernel.h> +#include <sound/initval.h> +#include <linux/kmod.h> +#include <linux/slab.h> + +MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>"); +MODULE_DESCRIPTION("ALSA sequencer device management"); +MODULE_LICENSE("GPL"); + +/* + * driver list + */ +typedef struct ops_list ops_list_t; + +/* driver state */ +#define DRIVER_EMPTY 0 +#define DRIVER_LOADED (1<<0) +#define DRIVER_REQUESTED (1<<1) +#define DRIVER_LOCKED (1<<2) + +struct ops_list { + char id[ID_LEN]; /* driver id */ + int driver; /* driver state */ + int used; /* reference counter */ + int argsize; /* argument size */ + + /* operators */ + snd_seq_dev_ops_t ops; + + /* registred devices */ + struct list_head dev_list; /* list of devices */ + int num_devices; /* number of associated devices */ + int num_init_devices; /* number of initialized devices */ + struct semaphore reg_mutex; + + struct list_head list; /* next driver */ +}; + + +static LIST_HEAD(opslist); +static int num_ops; +static DECLARE_MUTEX(ops_mutex); +static snd_info_entry_t *info_entry = NULL; + +/* + * prototypes + */ +static int snd_seq_device_free(snd_seq_device_t *dev); +static int snd_seq_device_dev_free(snd_device_t *device); +static int snd_seq_device_dev_register(snd_device_t *device); +static int snd_seq_device_dev_disconnect(snd_device_t *device); +static int snd_seq_device_dev_unregister(snd_device_t *device); + +static int init_device(snd_seq_device_t *dev, ops_list_t *ops); +static int free_device(snd_seq_device_t *dev, ops_list_t *ops); +static ops_list_t *find_driver(char *id, int create_if_empty); +static ops_list_t *create_driver(char *id); +static void unlock_driver(ops_list_t *ops); +static void remove_drivers(void); + +/* + * show all drivers and their status + */ + +static void snd_seq_device_info(snd_info_entry_t *entry, snd_info_buffer_t * buffer) +{ + struct list_head *head; + + down(&ops_mutex); + list_for_each(head, &opslist) { + ops_list_t *ops = list_entry(head, ops_list_t, list); + snd_iprintf(buffer, "snd-%s%s%s%s,%d\n", + ops->id, + ops->driver & DRIVER_LOADED ? ",loaded" : (ops->driver == DRIVER_EMPTY ? ",empty" : ""), + ops->driver & DRIVER_REQUESTED ? ",requested" : "", + ops->driver & DRIVER_LOCKED ? ",locked" : "", + ops->num_devices); + } + up(&ops_mutex); +} + +/* + * load all registered drivers (called from seq_clientmgr.c) + */ + +#ifdef CONFIG_KMOD +/* avoid auto-loading during module_init() */ +static int snd_seq_in_init; +void snd_seq_autoload_lock(void) +{ + snd_seq_in_init++; +} + +void snd_seq_autoload_unlock(void) +{ + snd_seq_in_init--; +} +#endif + +void snd_seq_device_load_drivers(void) +{ +#ifdef CONFIG_KMOD + struct list_head *head; + + /* Calling request_module during module_init() + * may cause blocking. + */ + if (snd_seq_in_init) + return; + + if (! current->fs->root) + return; + + down(&ops_mutex); + list_for_each(head, &opslist) { + ops_list_t *ops = list_entry(head, ops_list_t, list); + if (! (ops->driver & DRIVER_LOADED) && + ! (ops->driver & DRIVER_REQUESTED)) { + ops->used++; + up(&ops_mutex); + ops->driver |= DRIVER_REQUESTED; + request_module("snd-%s", ops->id); + down(&ops_mutex); + ops->used--; + } + } + up(&ops_mutex); +#endif +} + +/* + * register a sequencer device + * card = card info (NULL allowed) + * device = device number (if any) + * id = id of driver + * result = return pointer (NULL allowed if unnecessary) + */ +int snd_seq_device_new(snd_card_t *card, int device, char *id, int argsize, + snd_seq_device_t **result) +{ + snd_seq_device_t *dev; + ops_list_t *ops; + int err; + static snd_device_ops_t dops = { + .dev_free = snd_seq_device_dev_free, + .dev_register = snd_seq_device_dev_register, + .dev_disconnect = snd_seq_device_dev_disconnect, + .dev_unregister = snd_seq_device_dev_unregister + }; + + if (result) + *result = NULL; + + snd_assert(id != NULL, return -EINVAL); + + ops = find_driver(id, 1); + if (ops == NULL) + return -ENOMEM; + + dev = kcalloc(1, sizeof(*dev)*2 + argsize, GFP_KERNEL); + if (dev == NULL) { + unlock_driver(ops); + return -ENOMEM; + } + + /* set up device info */ + dev->card = card; + dev->device = device; + strlcpy(dev->id, id, sizeof(dev->id)); + dev->argsize = argsize; + dev->status = SNDRV_SEQ_DEVICE_FREE; + + /* add this device to the list */ + down(&ops->reg_mutex); + list_add_tail(&dev->list, &ops->dev_list); + ops->num_devices++; + up(&ops->reg_mutex); + + unlock_driver(ops); + + if ((err = snd_device_new(card, SNDRV_DEV_SEQUENCER, dev, &dops)) < 0) { + snd_seq_device_free(dev); + return err; + } + + if (result) + *result = dev; + + return 0; +} + +/* + * free the existing device + */ +static int snd_seq_device_free(snd_seq_device_t *dev) +{ + ops_list_t *ops; + + snd_assert(dev != NULL, return -EINVAL); + + ops = find_driver(dev->id, 0); + if (ops == NULL) + return -ENXIO; + + /* remove the device from the list */ + down(&ops->reg_mutex); + list_del(&dev->list); + ops->num_devices--; + up(&ops->reg_mutex); + + free_device(dev, ops); + if (dev->private_free) + dev->private_free(dev); + kfree(dev); + + unlock_driver(ops); + + return 0; +} + +static int snd_seq_device_dev_free(snd_device_t *device) +{ + snd_seq_device_t *dev = device->device_data; + return snd_seq_device_free(dev); +} + +/* + * register the device + */ +static int snd_seq_device_dev_register(snd_device_t *device) +{ + snd_seq_device_t *dev = device->device_data; + ops_list_t *ops; + + ops = find_driver(dev->id, 0); + if (ops == NULL) + return -ENOENT; + + /* initialize this device if the corresponding driver was + * already loaded + */ + if (ops->driver & DRIVER_LOADED) + init_device(dev, ops); + + unlock_driver(ops); + return 0; +} + +/* + * disconnect the device + */ +static int snd_seq_device_dev_disconnect(snd_device_t *device) +{ + snd_seq_device_t *dev = device->device_data; + ops_list_t *ops; + + ops = find_driver(dev->id, 0); + if (ops == NULL) + return -ENOENT; + + free_device(dev, ops); + + unlock_driver(ops); + return 0; +} + +/* + * unregister the existing device + */ +static int snd_seq_device_dev_unregister(snd_device_t *device) +{ + snd_seq_device_t *dev = device->device_data; + return snd_seq_device_free(dev); +} + +/* + * register device driver + * id = driver id + * entry = driver operators - duplicated to each instance + */ +int snd_seq_device_register_driver(char *id, snd_seq_dev_ops_t *entry, int argsize) +{ + struct list_head *head; + ops_list_t *ops; + + if (id == NULL || entry == NULL || + entry->init_device == NULL || entry->free_device == NULL) + return -EINVAL; + + snd_seq_autoload_lock(); + ops = find_driver(id, 1); + if (ops == NULL) { + snd_seq_autoload_unlock(); + return -ENOMEM; + } + if (ops->driver & DRIVER_LOADED) { + snd_printk(KERN_WARNING "driver_register: driver '%s' already exists\n", id); + unlock_driver(ops); + snd_seq_autoload_unlock(); + return -EBUSY; + } + + down(&ops->reg_mutex); + /* copy driver operators */ + ops->ops = *entry; + ops->driver |= DRIVER_LOADED; + ops->argsize = argsize; + + /* initialize existing devices if necessary */ + list_for_each(head, &ops->dev_list) { + snd_seq_device_t *dev = list_entry(head, snd_seq_device_t, list); + init_device(dev, ops); + } + up(&ops->reg_mutex); + + unlock_driver(ops); + snd_seq_autoload_unlock(); + + return 0; +} + + +/* + * create driver record + */ +static ops_list_t * create_driver(char *id) +{ + ops_list_t *ops; + + ops = kmalloc(sizeof(*ops), GFP_KERNEL); + if (ops == NULL) + return ops; + memset(ops, 0, sizeof(*ops)); + + /* set up driver entry */ + strlcpy(ops->id, id, sizeof(ops->id)); + init_MUTEX(&ops->reg_mutex); + ops->driver = DRIVER_EMPTY; + INIT_LIST_HEAD(&ops->dev_list); + /* lock this instance */ + ops->used = 1; + + /* register driver entry */ + down(&ops_mutex); + list_add_tail(&ops->list, &opslist); + num_ops++; + up(&ops_mutex); + + return ops; +} + + +/* + * unregister the specified driver + */ +int snd_seq_device_unregister_driver(char *id) +{ + struct list_head *head; + ops_list_t *ops; + + ops = find_driver(id, 0); + if (ops == NULL) + return -ENXIO; + if (! (ops->driver & DRIVER_LOADED) || + (ops->driver & DRIVER_LOCKED)) { + snd_printk(KERN_ERR "driver_unregister: cannot unload driver '%s': status=%x\n", id, ops->driver); + unlock_driver(ops); + return -EBUSY; + } + + /* close and release all devices associated with this driver */ + down(&ops->reg_mutex); + ops->driver |= DRIVER_LOCKED; /* do not remove this driver recursively */ + list_for_each(head, &ops->dev_list) { + snd_seq_device_t *dev = list_entry(head, snd_seq_device_t, list); + free_device(dev, ops); + } + + ops->driver = 0; + if (ops->num_init_devices > 0) + snd_printk(KERN_ERR "free_driver: init_devices > 0!! (%d)\n", ops->num_init_devices); + up(&ops->reg_mutex); + + unlock_driver(ops); + + /* remove empty driver entries */ + remove_drivers(); + + return 0; +} + + +/* + * remove empty driver entries + */ +static void remove_drivers(void) +{ + struct list_head *head; + + down(&ops_mutex); + head = opslist.next; + while (head != &opslist) { + ops_list_t *ops = list_entry(head, ops_list_t, list); + if (! (ops->driver & DRIVER_LOADED) && + ops->used == 0 && ops->num_devices == 0) { + head = head->next; + list_del(&ops->list); + kfree(ops); + num_ops--; + } else + head = head->next; + } + up(&ops_mutex); +} + +/* + * initialize the device - call init_device operator + */ +static int init_device(snd_seq_device_t *dev, ops_list_t *ops) +{ + if (! (ops->driver & DRIVER_LOADED)) + return 0; /* driver is not loaded yet */ + if (dev->status != SNDRV_SEQ_DEVICE_FREE) + return 0; /* already initialized */ + if (ops->argsize != dev->argsize) { + snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n", dev->name, ops->id, ops->argsize, dev->argsize); + return -EINVAL; + } + if (ops->ops.init_device(dev) >= 0) { + dev->status = SNDRV_SEQ_DEVICE_REGISTERED; + ops->num_init_devices++; + } else { + snd_printk(KERN_ERR "init_device failed: %s: %s\n", dev->name, dev->id); + } + + return 0; +} + +/* + * release the device - call free_device operator + */ +static int free_device(snd_seq_device_t *dev, ops_list_t *ops) +{ + int result; + + if (! (ops->driver & DRIVER_LOADED)) + return 0; /* driver is not loaded yet */ + if (dev->status != SNDRV_SEQ_DEVICE_REGISTERED) + return 0; /* not registered */ + if (ops->argsize != dev->argsize) { + snd_printk(KERN_ERR "incompatible device '%s' for plug-in '%s' (%d %d)\n", dev->name, ops->id, ops->argsize, dev->argsize); + return -EINVAL; + } + if ((result = ops->ops.free_device(dev)) >= 0 || result == -ENXIO) { + dev->status = SNDRV_SEQ_DEVICE_FREE; + dev->driver_data = NULL; + ops->num_init_devices--; + } else { + snd_printk(KERN_ERR "free_device failed: %s: %s\n", dev->name, dev->id); + } + + return 0; +} + +/* + * find the matching driver with given id + */ +static ops_list_t * find_driver(char *id, int create_if_empty) +{ + struct list_head *head; + + down(&ops_mutex); + list_for_each(head, &opslist) { + ops_list_t *ops = list_entry(head, ops_list_t, list); + if (strcmp(ops->id, id) == 0) { + ops->used++; + up(&ops_mutex); + return ops; + } + } + up(&ops_mutex); + if (create_if_empty) + return create_driver(id); + return NULL; +} + +static void unlock_driver(ops_list_t *ops) +{ + down(&ops_mutex); + ops->used--; + up(&ops_mutex); +} + + +/* + * module part + */ + +static int __init alsa_seq_device_init(void) +{ + 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_size = 2048; + info_entry->c.text.read = snd_seq_device_info; + if (snd_info_register(info_entry) < 0) { + snd_info_free_entry(info_entry); + return -ENOMEM; + } + return 0; +} + +static void __exit alsa_seq_device_exit(void) +{ + remove_drivers(); + snd_info_unregister(info_entry); + 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 |