[系统运维]Linux Alsa声卡驱动（2）：代码分析

一：初始化/注册声卡设备

kernel\sound\core：sound.c

int __init alsa_sound_init(void)
{
    ... ...
	if (register_chrdev(major, "alsa", &snd_fops)) 
    ... ...
}

static const struct file_operations snd_fops =
{
	.owner =	THIS_MODULE,
	.open =		snd_open,
	.llseek =	noop_llseek,
};

static int snd_open(struct inode *inode, struct file *file)
{
	unsigned int minor = iminor(inode);
	struct snd_minor *mptr = NULL;
	const struct file_operations *new_fops;

	mptr = snd_minors[minor];
    ... ...
	new_fops = fops_get(mptr->f_ops);
    ... ...
}

static struct snd_minor *snd_minors[SNDRV_OS_MINORS];

struct snd_minor {
	int type;			/* SNDRV_DEVICE_TYPE_XXX */
	int card;			/* card number */
	int device;			/* device number */
	const struct file_operations *f_ops;	/* file operations */
	void *private_data;		/* private data for f_ops->open */
	struct device *dev;		/* device for sysfs */
	struct snd_card *

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