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![Takashi Iwai](/assets/img/avatar_default.png)
There are a few places doing assignments in if condition in ALSA core code, which is a bad coding style that may confuse readers and occasionally lead to bugs. This patch is merely for coding-style fixes, no functional changes. Link: https://lore.kernel.org/r/20210608140540.17885-54-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
427 lines
10 KiB
C
427 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Advanced Linux Sound Architecture
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* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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*/
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/time.h>
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/debugfs.h>
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#include <sound/core.h>
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#include <sound/minors.h>
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#include <sound/info.h>
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#include <sound/control.h>
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#include <sound/initval.h>
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#include <linux/kmod.h>
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#include <linux/mutex.h>
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static int major = CONFIG_SND_MAJOR;
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int snd_major;
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EXPORT_SYMBOL(snd_major);
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static int cards_limit = 1;
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MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
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MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
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MODULE_LICENSE("GPL");
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module_param(major, int, 0444);
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MODULE_PARM_DESC(major, "Major # for sound driver.");
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module_param(cards_limit, int, 0444);
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MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
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MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
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/* this one holds the actual max. card number currently available.
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* as default, it's identical with cards_limit option. when more
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* modules are loaded manually, this limit number increases, too.
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*/
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int snd_ecards_limit;
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EXPORT_SYMBOL(snd_ecards_limit);
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#ifdef CONFIG_SND_DEBUG
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struct dentry *sound_debugfs_root;
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EXPORT_SYMBOL_GPL(sound_debugfs_root);
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#endif
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static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
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static DEFINE_MUTEX(sound_mutex);
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#ifdef CONFIG_MODULES
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/**
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* snd_request_card - try to load the card module
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* @card: the card number
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*
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* Tries to load the module "snd-card-X" for the given card number
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* via request_module. Returns immediately if already loaded.
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*/
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void snd_request_card(int card)
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{
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if (snd_card_locked(card))
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return;
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if (card < 0 || card >= cards_limit)
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return;
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request_module("snd-card-%i", card);
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}
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EXPORT_SYMBOL(snd_request_card);
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static void snd_request_other(int minor)
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{
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char *str;
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switch (minor) {
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case SNDRV_MINOR_SEQUENCER: str = "snd-seq"; break;
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case SNDRV_MINOR_TIMER: str = "snd-timer"; break;
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default: return;
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}
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request_module(str);
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}
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#endif /* modular kernel */
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/**
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* snd_lookup_minor_data - get user data of a registered device
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* @minor: the minor number
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* @type: device type (SNDRV_DEVICE_TYPE_XXX)
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*
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* Checks that a minor device with the specified type is registered, and returns
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* its user data pointer.
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*
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* This function increments the reference counter of the card instance
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* if an associated instance with the given minor number and type is found.
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* The caller must call snd_card_unref() appropriately later.
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*
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* Return: The user data pointer if the specified device is found. %NULL
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* otherwise.
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*/
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void *snd_lookup_minor_data(unsigned int minor, int type)
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{
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struct snd_minor *mreg;
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void *private_data;
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if (minor >= ARRAY_SIZE(snd_minors))
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return NULL;
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mutex_lock(&sound_mutex);
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mreg = snd_minors[minor];
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if (mreg && mreg->type == type) {
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private_data = mreg->private_data;
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if (private_data && mreg->card_ptr)
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get_device(&mreg->card_ptr->card_dev);
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} else
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private_data = NULL;
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mutex_unlock(&sound_mutex);
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return private_data;
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}
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EXPORT_SYMBOL(snd_lookup_minor_data);
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#ifdef CONFIG_MODULES
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static struct snd_minor *autoload_device(unsigned int minor)
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{
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int dev;
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mutex_unlock(&sound_mutex); /* release lock temporarily */
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dev = SNDRV_MINOR_DEVICE(minor);
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if (dev == SNDRV_MINOR_CONTROL) {
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/* /dev/aloadC? */
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int card = SNDRV_MINOR_CARD(minor);
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struct snd_card *ref = snd_card_ref(card);
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if (!ref)
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snd_request_card(card);
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else
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snd_card_unref(ref);
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} else if (dev == SNDRV_MINOR_GLOBAL) {
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/* /dev/aloadSEQ */
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snd_request_other(minor);
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}
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mutex_lock(&sound_mutex); /* reacuire lock */
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return snd_minors[minor];
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}
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#else /* !CONFIG_MODULES */
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#define autoload_device(minor) NULL
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#endif /* CONFIG_MODULES */
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static int snd_open(struct inode *inode, struct file *file)
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{
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unsigned int minor = iminor(inode);
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struct snd_minor *mptr = NULL;
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const struct file_operations *new_fops;
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int err = 0;
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if (minor >= ARRAY_SIZE(snd_minors))
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return -ENODEV;
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mutex_lock(&sound_mutex);
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mptr = snd_minors[minor];
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if (mptr == NULL) {
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mptr = autoload_device(minor);
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if (!mptr) {
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mutex_unlock(&sound_mutex);
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return -ENODEV;
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}
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}
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new_fops = fops_get(mptr->f_ops);
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mutex_unlock(&sound_mutex);
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if (!new_fops)
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return -ENODEV;
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replace_fops(file, new_fops);
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if (file->f_op->open)
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err = file->f_op->open(inode, file);
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return err;
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}
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static const struct file_operations snd_fops =
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{
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.owner = THIS_MODULE,
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.open = snd_open,
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.llseek = noop_llseek,
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};
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#ifdef CONFIG_SND_DYNAMIC_MINORS
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static int snd_find_free_minor(int type, struct snd_card *card, int dev)
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{
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int minor;
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/* static minors for module auto loading */
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if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
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return SNDRV_MINOR_SEQUENCER;
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if (type == SNDRV_DEVICE_TYPE_TIMER)
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return SNDRV_MINOR_TIMER;
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for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
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/* skip static minors still used for module auto loading */
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if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
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continue;
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if (minor == SNDRV_MINOR_SEQUENCER ||
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minor == SNDRV_MINOR_TIMER)
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continue;
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if (!snd_minors[minor])
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return minor;
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}
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return -EBUSY;
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}
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#else
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static int snd_find_free_minor(int type, struct snd_card *card, int dev)
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{
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int minor;
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switch (type) {
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case SNDRV_DEVICE_TYPE_SEQUENCER:
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case SNDRV_DEVICE_TYPE_TIMER:
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minor = type;
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break;
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case SNDRV_DEVICE_TYPE_CONTROL:
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if (snd_BUG_ON(!card))
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return -EINVAL;
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minor = SNDRV_MINOR(card->number, type);
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break;
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case SNDRV_DEVICE_TYPE_HWDEP:
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case SNDRV_DEVICE_TYPE_RAWMIDI:
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case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
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case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
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case SNDRV_DEVICE_TYPE_COMPRESS:
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if (snd_BUG_ON(!card))
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return -EINVAL;
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minor = SNDRV_MINOR(card->number, type + dev);
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break;
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default:
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return -EINVAL;
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}
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if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
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return -EINVAL;
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if (snd_minors[minor])
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return -EBUSY;
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return minor;
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}
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#endif
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/**
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* snd_register_device - Register the ALSA device file for the card
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* @type: the device type, SNDRV_DEVICE_TYPE_XXX
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* @card: the card instance
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* @dev: the device index
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* @f_ops: the file operations
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* @private_data: user pointer for f_ops->open()
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* @device: the device to register
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*
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* Registers an ALSA device file for the given card.
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* The operators have to be set in reg parameter.
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*
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* Return: Zero if successful, or a negative error code on failure.
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*/
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int snd_register_device(int type, struct snd_card *card, int dev,
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const struct file_operations *f_ops,
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void *private_data, struct device *device)
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{
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int minor;
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int err = 0;
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struct snd_minor *preg;
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if (snd_BUG_ON(!device))
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return -EINVAL;
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preg = kmalloc(sizeof *preg, GFP_KERNEL);
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if (preg == NULL)
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return -ENOMEM;
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preg->type = type;
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preg->card = card ? card->number : -1;
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preg->device = dev;
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preg->f_ops = f_ops;
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preg->private_data = private_data;
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preg->card_ptr = card;
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mutex_lock(&sound_mutex);
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minor = snd_find_free_minor(type, card, dev);
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if (minor < 0) {
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err = minor;
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goto error;
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}
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preg->dev = device;
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device->devt = MKDEV(major, minor);
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err = device_add(device);
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if (err < 0)
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goto error;
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snd_minors[minor] = preg;
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error:
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mutex_unlock(&sound_mutex);
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if (err < 0)
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kfree(preg);
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return err;
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}
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EXPORT_SYMBOL(snd_register_device);
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/**
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* snd_unregister_device - unregister the device on the given card
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* @dev: the device instance
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*
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* Unregisters the device file already registered via
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* snd_register_device().
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*
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* Return: Zero if successful, or a negative error code on failure.
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*/
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int snd_unregister_device(struct device *dev)
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{
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int minor;
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struct snd_minor *preg;
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mutex_lock(&sound_mutex);
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for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
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preg = snd_minors[minor];
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if (preg && preg->dev == dev) {
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snd_minors[minor] = NULL;
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device_del(dev);
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kfree(preg);
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break;
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}
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}
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mutex_unlock(&sound_mutex);
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if (minor >= ARRAY_SIZE(snd_minors))
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return -ENOENT;
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return 0;
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}
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EXPORT_SYMBOL(snd_unregister_device);
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#ifdef CONFIG_SND_PROC_FS
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/*
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* INFO PART
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*/
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static const char *snd_device_type_name(int type)
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{
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switch (type) {
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case SNDRV_DEVICE_TYPE_CONTROL:
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return "control";
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case SNDRV_DEVICE_TYPE_HWDEP:
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return "hardware dependent";
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case SNDRV_DEVICE_TYPE_RAWMIDI:
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return "raw midi";
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case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
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return "digital audio playback";
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case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
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return "digital audio capture";
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case SNDRV_DEVICE_TYPE_SEQUENCER:
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return "sequencer";
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case SNDRV_DEVICE_TYPE_TIMER:
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return "timer";
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case SNDRV_DEVICE_TYPE_COMPRESS:
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return "compress";
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default:
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return "?";
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}
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}
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static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
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{
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int minor;
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struct snd_minor *mptr;
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mutex_lock(&sound_mutex);
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for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
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mptr = snd_minors[minor];
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if (!mptr)
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continue;
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if (mptr->card >= 0) {
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if (mptr->device >= 0)
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snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
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minor, mptr->card, mptr->device,
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snd_device_type_name(mptr->type));
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else
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snd_iprintf(buffer, "%3i: [%2i] : %s\n",
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minor, mptr->card,
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snd_device_type_name(mptr->type));
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} else
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snd_iprintf(buffer, "%3i: : %s\n", minor,
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snd_device_type_name(mptr->type));
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}
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mutex_unlock(&sound_mutex);
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}
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int __init snd_minor_info_init(void)
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{
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struct snd_info_entry *entry;
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entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
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if (!entry)
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return -ENOMEM;
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entry->c.text.read = snd_minor_info_read;
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return snd_info_register(entry); /* freed in error path */
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}
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#endif /* CONFIG_SND_PROC_FS */
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/*
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* INIT PART
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*/
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static int __init alsa_sound_init(void)
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{
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snd_major = major;
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snd_ecards_limit = cards_limit;
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if (register_chrdev(major, "alsa", &snd_fops)) {
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pr_err("ALSA core: unable to register native major device number %d\n", major);
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return -EIO;
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}
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if (snd_info_init() < 0) {
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unregister_chrdev(major, "alsa");
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return -ENOMEM;
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}
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#ifdef CONFIG_SND_DEBUG
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sound_debugfs_root = debugfs_create_dir("sound", NULL);
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#endif
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#ifndef MODULE
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pr_info("Advanced Linux Sound Architecture Driver Initialized.\n");
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#endif
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return 0;
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}
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static void __exit alsa_sound_exit(void)
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{
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#ifdef CONFIG_SND_DEBUG
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debugfs_remove(sound_debugfs_root);
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#endif
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snd_info_done();
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unregister_chrdev(major, "alsa");
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}
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subsys_initcall(alsa_sound_init);
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module_exit(alsa_sound_exit);
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