Linux 如何管理设备驱动,linux设备驱动——一个驱动怎么管理多个设备

た入场券 2023-01-21 08:26 31阅读 0赞

linux设备驱动——一个驱动如何管理多个设备

/\*

\* 说明：用于演示一个驱动如何管理多个设备。

\*/

\#include

\#include "ioctl.h"

\#define FSDEV\_MAJOR250

\#defineFSDEV\_MINOR0

\#define FSDEV\_NR2

\#define FSDEV\_NAME"fsdev"

struct fsdev \{

struct cdev cdev;

unsigned char buf\[256\];

\};

static struct fsdev \*fsdev\[FSDEV\_NR\];

static int fschr\_open(struct inode \*inode, struct file \*filp)

struct fsdev \*fsdev;

/\* 根据保存在inode节点中的cdev指针，反向查询到包含该cdev的结构体，

\* 将该结构体指针保存在打开的文件结构体的私有数据中，可以在之后

\* 的read、write以及ioctl当中通过file结构体指针顺利获得反查得到的

\* 结构体指针，这是实现一个驱动管理多个设备的关键

\*/

fsdev = container\_of(inode->i\_cdev, struct fsdev, cdev);

filp->private\_data = fsdev;

return 0;

static int fschr\_close(struct inode \*inode, struct file \*filp)

return 0;

static ssize\_t fschr\_read(struct file \*filp, char \_\_user \*buf, size\_t count, loff\_t \*fops)

int len;

int ret;

struct fsdev \*fsdev = filp->private\_data;//通过filp的private\_data得到是哪一个设备的操作

len = count > 256 ? 256 : count;

ret = copy\_to\_user(buf, fsdev->buf, len);

return len - ret;

static ssize\_t fschr\_write(struct file \*filp, const char \_\_user \*buf, size\_t count, loff\_t \*fops)

int len;

int ret;

struct fsdev \*fsdev = filp->private\_data;

len = count > 256 ? 256 : count;

ret = copy\_from\_user(fsdev->buf, buf, len);

return len - ret;

static int fschr\_ioctl(struct inode \*inode, struct file \*filp, unsigned int cmd, unsigned long arg)

int ret = 0;

struct fsdev \*fsdev = filp->private\_data;

if (\_IOC\_TYPE(cmd) != FS\_IOC\_MAGIC)

return -ENOTTY;

if (\_IOC\_NR(cmd) > FS\_IOC\_MAXNR)

return -ENOTTY;

if (\_IOC\_DIR(cmd) & \_IOC\_READ)

ret = !access\_ok(VERIFY\_WRITE, (void \_\_user \*)arg, \_IOC\_SIZE(cmd));

else if (\_IOC\_DIR(cmd) & \_IOC\_WRITE)

ret = !access\_ok(VERIFY\_READ, (void \_\_user \*)arg, \_IOC\_SIZE(cmd));

if (ret)

return -EFAULT;

switch (cmd) \{

case FS\_IOC\_SET\_BUF:

memset(fsdev->buf, \*(char \*)arg, sizeof(fsdev->buf));

break;

return 0;

static struct file\_operations fsfops = \{

.owner = THIS\_MODULE,

.open = fschr\_open,

.release = fschr\_close,

.read = fschr\_read,

.write = fschr\_write,

.ioctl = fschr\_ioctl

\};

static int \_\_init fschr\_init(void)

int i;

int ret;

int alloc\_num = 0;

int add\_num = 0;

dev\_t devno;

devno = MKDEV(FSDEV\_MAJOR, FSDEV\_MINOR);

ret = register\_chrdev\_region(devno, FSDEV\_NR, FSDEV\_NAME);

if (ret) \{

printk(KERN\_ERR "fschr: register chrdev region failed\\n");

goto reg\_err;

for (i = 0; i < FSDEV\_NR; i++)

fsdev\[i\] = (struct fsdev \*)kzalloc(sizeof(struct fsdev), GFP\_KERNEL);

if (!fsdev\[i\]) \{

printk(KERN\_ERR "fschr: kzalloc failure\\n");

alloc\_num = i;

ret = -ENOMEM;

goto alloc\_err;

alloc\_num = FSDEV\_NR;

for (i = 0; i < FSDEV\_NR; i++) \{

cdev\_init(&fsdev\[i\]->cdev, &fsfops);

fsdev\[i\]->cdev.owner = THIS\_MODULE;

ret = cdev\_add(&fsdev\[i\]->cdev, devno + i, 1);

if (ret) \{

printk(KERN\_ERR "fschr: add cdev failed");

add\_num = i;

goto add\_err;

return 0;

add\_err:

for (i = 0; i < add\_num; i++)

cdev\_del(&fsdev\[i\]->cdev);

alloc\_err:

for (i = 0; i < alloc\_num; i++)

kfree(fsdev\[i\]);

unregister\_chrdev\_region(devno, FSDEV\_NR);

reg\_err:

return ret;

static void \_\_exit fschr\_exit(void)

int i;

dev\_t devno;

devno = MKDEV(FSDEV\_MAJOR, FSDEV\_MINOR);

for (i = 0; i < FSDEV\_NR; i++)

cdev\_del(&fsdev\[i\]->cdev);

for (i = 0; i < FSDEV\_NR; i++)

kfree(fsdev\[i\]);

unregister\_chrdev\_region(devno, FSDEV\_NR);

module\_init(fschr\_init);

module\_exit(fschr\_exit);

MODULE\_LICENSE("Dual BSD/GPL");

MODULE\_AUTHOR("xxxx");

MODULE\_DESCRIPTION("Character device driver example for FSC100 development board");

ioctl.h

\#ifndef \_\_IOCTL\_\_

\#define \_\_IOCTL\_\_

\#define FS\_IOC\_MAGIC'f'

\#define FS\_IOC\_MAXNR1

\#defineFS\_IOC\_SET\_BUF\_IOW(FS\_IOC\_MAGIC, 1, char)

\#endif

Linux 如何管理设备驱动,linux设备驱动——一个驱动怎么管理多个设备

发表评论取消回复

还没有评论，来说两句吧...

相关阅读

相关 Linux 如何管理设备驱动,linux设备驱动——一个驱动怎么管理多个设备

相关 linux phy驱动和设备匹配,linux Phy 设备驱动

相关 Linux设备驱动12

相关 Linux终端设备驱动

相关 Linux终端设备驱动

相关 Linux设备驱动学习(3) 设备sleepy

相关 Linux设备驱动程序——字符设备驱动编程

相关 Linux设备驱动程序——设备驱动编程基础

相关 Linux设备模型－－驱动

相关 Linux字符设备驱动——杂项设备驱动模型