diff options
Diffstat (limited to 'sound/sound_core.c')
| -rw-r--r-- | sound/sound_core.c | 625 |
1 files changed, 625 insertions, 0 deletions
diff --git a/sound/sound_core.c b/sound/sound_core.c new file mode 100644 index 000000000..dd64c4b19 --- /dev/null +++ b/sound/sound_core.c @@ -0,0 +1,625 @@ +/* + * Sound core. This file is composed of two parts. sound_class + * which is common to both OSS and ALSA and OSS sound core which + * is used OSS or emulation of it. + */ + +/* + * First, the common part. + */ +#include <linux/module.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/kdev_t.h> +#include <linux/major.h> +#include <sound/core.h> + +#ifdef CONFIG_SOUND_OSS_CORE +static int __init init_oss_soundcore(void); +static void cleanup_oss_soundcore(void); +#else +static inline int init_oss_soundcore(void) { return 0; } +static inline void cleanup_oss_soundcore(void) { } +#endif + +struct class *sound_class; +EXPORT_SYMBOL(sound_class); + +MODULE_DESCRIPTION("Core sound module"); +MODULE_AUTHOR("Alan Cox"); +MODULE_LICENSE("GPL"); + +static char *sound_devnode(struct device *dev, umode_t *mode) +{ + if (MAJOR(dev->devt) == SOUND_MAJOR) + return NULL; + return kasprintf(GFP_KERNEL, "snd/%s", dev_name(dev)); +} + +static int __init init_soundcore(void) +{ + int rc; + + rc = init_oss_soundcore(); + if (rc) + return rc; + + sound_class = class_create(THIS_MODULE, "sound"); + if (IS_ERR(sound_class)) { + cleanup_oss_soundcore(); + return PTR_ERR(sound_class); + } + + sound_class->devnode = sound_devnode; + + return 0; +} + +static void __exit cleanup_soundcore(void) +{ + cleanup_oss_soundcore(); + class_destroy(sound_class); +} + +subsys_initcall(init_soundcore); +module_exit(cleanup_soundcore); + + +#ifdef CONFIG_SOUND_OSS_CORE +/* + * OSS sound core handling. Breaks out sound functions to submodules + * + * Author: Alan Cox <alan@lxorguk.ukuu.org.uk> + * + * Fixes: + * + * + * 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. + * + * -------------------- + * + * Top level handler for the sound subsystem. Various devices can + * plug into this. The fact they don't all go via OSS doesn't mean + * they don't have to implement the OSS API. There is a lot of logic + * to keeping much of the OSS weight out of the code in a compatibility + * module, but it's up to the driver to rember to load it... + * + * The code provides a set of functions for registration of devices + * by type. This is done rather than providing a single call so that + * we can hide any future changes in the internals (eg when we go to + * 32bit dev_t) from the modules and their interface. + * + * Secondly we need to allocate the dsp, dsp16 and audio devices as + * one. Thus we misuse the chains a bit to simplify this. + * + * Thirdly to make it more fun and for 2.3.x and above we do all + * of this using fine grained locking. + * + * FIXME: we have to resolve modules and fine grained load/unload + * locking at some point in 2.3.x. + */ + +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/sound.h> +#include <linux/kmod.h> + +#define SOUND_STEP 16 + +struct sound_unit +{ + int unit_minor; + const struct file_operations *unit_fops; + struct sound_unit *next; + char name[32]; +}; + +/* + * By default, OSS sound_core claims full legacy minor range (0-255) + * of SOUND_MAJOR to trap open attempts to any sound minor and + * requests modules using custom sound-slot/service-* module aliases. + * The only benefit of doing this is allowing use of custom module + * aliases instead of the standard char-major-* ones. This behavior + * prevents alternative OSS implementation and is scheduled to be + * removed. + * + * CONFIG_SOUND_OSS_CORE_PRECLAIM and soundcore.preclaim_oss kernel + * parameter are added to allow distros and developers to try and + * switch to alternative implementations without needing to rebuild + * the kernel in the meantime. If preclaim_oss is non-zero, the + * kernel will behave the same as before. All SOUND_MAJOR minors are + * preclaimed and the custom module aliases along with standard chrdev + * ones are emitted if a missing device is opened. If preclaim_oss is + * zero, sound_core only grabs what's actually in use and for missing + * devices only the standard chrdev aliases are requested. + * + * All these clutters are scheduled to be removed along with + * sound-slot/service-* module aliases. + */ +#ifdef CONFIG_SOUND_OSS_CORE_PRECLAIM +static int preclaim_oss = 1; +#else +static int preclaim_oss = 0; +#endif + +module_param(preclaim_oss, int, 0444); + +static int soundcore_open(struct inode *, struct file *); + +static const struct file_operations soundcore_fops = +{ + /* We must have an owner or the module locking fails */ + .owner = THIS_MODULE, + .open = soundcore_open, + .llseek = noop_llseek, +}; + +/* + * Low level list operator. Scan the ordered list, find a hole and + * join into it. Called with the lock asserted + */ + +static int __sound_insert_unit(struct sound_unit * s, struct sound_unit **list, const struct file_operations *fops, int index, int low, int top) +{ + int n=low; + + if (index < 0) { /* first free */ + + while (*list && (*list)->unit_minor<n) + list=&((*list)->next); + + while(n<top) + { + /* Found a hole ? */ + if(*list==NULL || (*list)->unit_minor>n) + break; + list=&((*list)->next); + n+=SOUND_STEP; + } + + if(n>=top) + return -ENOENT; + } else { + n = low+(index*16); + while (*list) { + if ((*list)->unit_minor==n) + return -EBUSY; + if ((*list)->unit_minor>n) + break; + list=&((*list)->next); + } + } + + /* + * Fill it in + */ + + s->unit_minor=n; + s->unit_fops=fops; + + /* + * Link it + */ + + s->next=*list; + *list=s; + + + return n; +} + +/* + * Remove a node from the chain. Called with the lock asserted + */ + +static struct sound_unit *__sound_remove_unit(struct sound_unit **list, int unit) +{ + while(*list) + { + struct sound_unit *p=*list; + if(p->unit_minor==unit) + { + *list=p->next; + return p; + } + list=&(p->next); + } + printk(KERN_ERR "Sound device %d went missing!\n", unit); + return NULL; +} + +/* + * This lock guards the sound loader list. + */ + +static DEFINE_SPINLOCK(sound_loader_lock); + +/* + * Allocate the controlling structure and add it to the sound driver + * list. Acquires locks as needed + */ + +static int sound_insert_unit(struct sound_unit **list, const struct file_operations *fops, int index, int low, int top, const char *name, umode_t mode, struct device *dev) +{ + struct sound_unit *s = kmalloc(sizeof(*s), GFP_KERNEL); + int r; + + if (!s) + return -ENOMEM; + + spin_lock(&sound_loader_lock); +retry: + r = __sound_insert_unit(s, list, fops, index, low, top); + spin_unlock(&sound_loader_lock); + + if (r < 0) + goto fail; + else if (r < SOUND_STEP) + sprintf(s->name, "sound/%s", name); + else + sprintf(s->name, "sound/%s%d", name, r / SOUND_STEP); + + if (!preclaim_oss) { + /* + * Something else might have grabbed the minor. If + * first free slot is requested, rescan with @low set + * to the next unit; otherwise, -EBUSY. + */ + r = __register_chrdev(SOUND_MAJOR, s->unit_minor, 1, s->name, + &soundcore_fops); + if (r < 0) { + spin_lock(&sound_loader_lock); + __sound_remove_unit(list, s->unit_minor); + if (index < 0) { + low = s->unit_minor + SOUND_STEP; + goto retry; + } + spin_unlock(&sound_loader_lock); + r = -EBUSY; + goto fail; + } + } + + device_create(sound_class, dev, MKDEV(SOUND_MAJOR, s->unit_minor), + NULL, "%s", s->name+6); + return s->unit_minor; + +fail: + kfree(s); + return r; +} + +/* + * Remove a unit. Acquires locks as needed. The drivers MUST have + * completed the removal before their file operations become + * invalid. + */ + +static void sound_remove_unit(struct sound_unit **list, int unit) +{ + struct sound_unit *p; + + spin_lock(&sound_loader_lock); + p = __sound_remove_unit(list, unit); + spin_unlock(&sound_loader_lock); + if (p) { + if (!preclaim_oss) + __unregister_chrdev(SOUND_MAJOR, p->unit_minor, 1, + p->name); + device_destroy(sound_class, MKDEV(SOUND_MAJOR, p->unit_minor)); + kfree(p); + } +} + +/* + * Allocations + * + * 0 *16 Mixers + * 1 *8 Sequencers + * 2 *16 Midi + * 3 *16 DSP + * 4 *16 SunDSP + * 5 *16 DSP16 + * 6 -- sndstat (obsolete) + * 7 *16 unused + * 8 -- alternate sequencer (see above) + * 9 *16 raw synthesizer access + * 10 *16 unused + * 11 *16 unused + * 12 *16 unused + * 13 *16 unused + * 14 *16 unused + * 15 *16 unused + */ + +static struct sound_unit *chains[SOUND_STEP]; + +/** + * register_sound_special_device - register a special sound node + * @fops: File operations for the driver + * @unit: Unit number to allocate + * @dev: device pointer + * + * Allocate a special sound device by minor number from the sound + * subsystem. + * + * Return: The allocated number is returned on success. On failure, + * a negative error code is returned. + */ + +int register_sound_special_device(const struct file_operations *fops, int unit, + struct device *dev) +{ + const int chain = unit % SOUND_STEP; + int max_unit = 256; + const char *name; + char _name[16]; + + switch (chain) { + case 0: + name = "mixer"; + break; + case 1: + name = "sequencer"; + if (unit >= SOUND_STEP) + goto __unknown; + max_unit = unit + 1; + break; + case 2: + name = "midi"; + break; + case 3: + name = "dsp"; + break; + case 4: + name = "audio"; + break; + case 5: + name = "dspW"; + break; + case 8: + name = "sequencer2"; + if (unit >= SOUND_STEP) + goto __unknown; + max_unit = unit + 1; + break; + case 9: + name = "dmmidi"; + break; + case 10: + name = "dmfm"; + break; + case 12: + name = "adsp"; + break; + case 13: + name = "amidi"; + break; + case 14: + name = "admmidi"; + break; + default: + { + __unknown: + sprintf(_name, "unknown%d", chain); + if (unit >= SOUND_STEP) + strcat(_name, "-"); + name = _name; + } + break; + } + return sound_insert_unit(&chains[chain], fops, -1, unit, max_unit, + name, 0600, dev); +} + +EXPORT_SYMBOL(register_sound_special_device); + +int register_sound_special(const struct file_operations *fops, int unit) +{ + return register_sound_special_device(fops, unit, NULL); +} + +EXPORT_SYMBOL(register_sound_special); + +/** + * register_sound_mixer - register a mixer device + * @fops: File operations for the driver + * @dev: Unit number to allocate + * + * Allocate a mixer device. Unit is the number of the mixer requested. + * Pass -1 to request the next free mixer unit. + * + * Return: On success, the allocated number is returned. On failure, + * a negative error code is returned. + */ + +int register_sound_mixer(const struct file_operations *fops, int dev) +{ + return sound_insert_unit(&chains[0], fops, dev, 0, 128, + "mixer", 0600, NULL); +} + +EXPORT_SYMBOL(register_sound_mixer); + +/* + * DSP's are registered as a triple. Register only one and cheat + * in open - see below. + */ + +/** + * register_sound_dsp - register a DSP device + * @fops: File operations for the driver + * @dev: Unit number to allocate + * + * Allocate a DSP device. Unit is the number of the DSP requested. + * Pass -1 to request the next free DSP unit. + * + * This function allocates both the audio and dsp device entries together + * and will always allocate them as a matching pair - eg dsp3/audio3 + * + * Return: On success, the allocated number is returned. On failure, + * a negative error code is returned. + */ + +int register_sound_dsp(const struct file_operations *fops, int dev) +{ + return sound_insert_unit(&chains[3], fops, dev, 3, 131, + "dsp", 0600, NULL); +} + +EXPORT_SYMBOL(register_sound_dsp); + +/** + * unregister_sound_special - unregister a special sound device + * @unit: unit number to allocate + * + * Release a sound device that was allocated with + * register_sound_special(). The unit passed is the return value from + * the register function. + */ + + +void unregister_sound_special(int unit) +{ + sound_remove_unit(&chains[unit % SOUND_STEP], unit); +} + +EXPORT_SYMBOL(unregister_sound_special); + +/** + * unregister_sound_mixer - unregister a mixer + * @unit: unit number to allocate + * + * Release a sound device that was allocated with register_sound_mixer(). + * The unit passed is the return value from the register function. + */ + +void unregister_sound_mixer(int unit) +{ + sound_remove_unit(&chains[0], unit); +} + +EXPORT_SYMBOL(unregister_sound_mixer); + +/** + * unregister_sound_dsp - unregister a DSP device + * @unit: unit number to allocate + * + * Release a sound device that was allocated with register_sound_dsp(). + * The unit passed is the return value from the register function. + * + * Both of the allocated units are released together automatically. + */ + +void unregister_sound_dsp(int unit) +{ + sound_remove_unit(&chains[3], unit); +} + + +EXPORT_SYMBOL(unregister_sound_dsp); + +static struct sound_unit *__look_for_unit(int chain, int unit) +{ + struct sound_unit *s; + + s=chains[chain]; + while(s && s->unit_minor <= unit) + { + if(s->unit_minor==unit) + return s; + s=s->next; + } + return NULL; +} + +static int soundcore_open(struct inode *inode, struct file *file) +{ + int chain; + int unit = iminor(inode); + struct sound_unit *s; + const struct file_operations *new_fops = NULL; + + chain=unit&0x0F; + if(chain==4 || chain==5) /* dsp/audio/dsp16 */ + { + unit&=0xF0; + unit|=3; + chain=3; + } + + spin_lock(&sound_loader_lock); + s = __look_for_unit(chain, unit); + if (s) + new_fops = fops_get(s->unit_fops); + if (preclaim_oss && !new_fops) { + spin_unlock(&sound_loader_lock); + + /* + * Please, don't change this order or code. + * For ALSA slot means soundcard and OSS emulation code + * comes as add-on modules which aren't depend on + * ALSA toplevel modules for soundcards, thus we need + * load them at first. [Jaroslav Kysela <perex@jcu.cz>] + */ + request_module("sound-slot-%i", unit>>4); + request_module("sound-service-%i-%i", unit>>4, chain); + + /* + * sound-slot/service-* module aliases are scheduled + * for removal in favor of the standard char-major-* + * module aliases. For the time being, generate both + * the legacy and standard module aliases to ease + * transition. + */ + if (request_module("char-major-%d-%d", SOUND_MAJOR, unit) > 0) + request_module("char-major-%d", SOUND_MAJOR); + + spin_lock(&sound_loader_lock); + s = __look_for_unit(chain, unit); + if (s) + new_fops = fops_get(s->unit_fops); + } + spin_unlock(&sound_loader_lock); + if (new_fops) { + /* + * We rely upon the fact that we can't be unloaded while the + * subdriver is there. + */ + int err = 0; + replace_fops(file, new_fops); + + if (file->f_op->open) + err = file->f_op->open(inode,file); + + return err; + } + return -ENODEV; +} + +MODULE_ALIAS_CHARDEV_MAJOR(SOUND_MAJOR); + +static void cleanup_oss_soundcore(void) +{ + /* We have nothing to really do here - we know the lists must be + empty */ + unregister_chrdev(SOUND_MAJOR, "sound"); +} + +static int __init init_oss_soundcore(void) +{ + if (preclaim_oss && + register_chrdev(SOUND_MAJOR, "sound", &soundcore_fops) < 0) { + printk(KERN_ERR "soundcore: sound device already in use.\n"); + return -EBUSY; + } + + return 0; +} + +#endif /* CONFIG_SOUND_OSS_CORE */ |