summaryrefslogtreecommitdiffstats
path: root/sound/sound_core.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--sound/sound_core.c625
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 */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 07:25:26 +0000