Porting device drivers to the 2.6 kernel

For what it's worth, I did consider keeping this material non-free for longer than the usual period. It is different from the usual news, and it has a slightly longer useful life. In the end, I decided against such a move; I would like these articles to be generally useful, and to serve as a contribution to the kernel project. Maintaining the same access policy also lets me fold some of the articles into the Kernel Page, which could use it - development news tends to slow down a lot during feature freezes.

So the driver porting articles go free after a week. We may yet do things differently for similar material in the future.

jon

One minor gripe is that the articles don't default to a printable page format (yes, I do promise to buy the next book of yours regardless ;-)

***parse error before dev_t;

i also added the <linux/fs.h> .
please any one help me .

prcdd.c:6:1: warning: "__KERNEL__" redefined
prcdd.c:1:1: warning: this is the location of the previous definition
prcdd.c:7:1: warning: "MODULE" redefined
prcdd.c:1:1: warning: this is the location of the previous definition
In file included from /usr/include/linux/fs.h:23,
from prcdd.c:11:
/usr/include/linux/string.h:8:2: warning: #warning Using kernel header in userland!
prcdd.c:12:25: asm/uaccess.h: No such file or directory
prcdd.c:17: warning: `struct file' declared inside parameter list
prcdd.c:17: warning: its scope is only this definition or declaration, which is probably not what you want
prcdd.c:17: warning: `struct inode' declared inside parameter list
prcdd.c:18: warning: `struct file' declared inside parameter list
prcdd.c:18: warning: `struct inode' declared inside parameter list
prcdd.c:26: variable `fops' has initializer but incomplete type
prcdd.c:27: unknown field `owner' specified in initializer
prcdd.c:27: warning: excess elements in struct initializer
prcdd.c:27: warning: (near initialization for `fops')
prcdd.c:28: unknown field `open' specified in initializer
prcdd.c:28: warning: excess elements in struct initializer
prcdd.c:28: warning: (near initialization for `fops')
prcdd.c:29: unknown field `release' specified in initializer
prcdd.c:29: warning: excess elements in struct initializer
prcdd.c:29: warning: (near initialization for `fops')
prcdd.c: In function `prcdd_init':
prcdd.c:34: warning: implicit declaration of function `register_chrdev'
prcdd.c:38: warning: implicit declaration of function `printk'
prcdd.c: In function `prcdd_exit':
prcdd.c:48: warning: implicit declaration of function `unregister_chrdev'
prcdd.c: At top level:
prcdd.c:55: warning: `struct file' declared inside parameter list
prcdd.c:55: warning: `struct inode' declared inside parameter list
prcdd.c:56: conflicting types for `prcdd_open'
prcdd.c:17: previous declaration of `prcdd_open'
prcdd.c: In function `prcdd_open':
prcdd.c:59: `EBUSY' undeclared (first use in this function)
prcdd.c:59: (Each undeclared identifier is reported only once
prcdd.c:59: for each function it appears in.)
prcdd.c:63: warning: implicit declaration of function `atomic_inc'
prcdd.c:63: union has no member named `usecount'
prcdd.c: At top level:
prcdd.c:67: warning: `struct file' declared inside parameter list
prcdd.c:67: warning: `struct inode' declared inside parameter list
prcdd.c:68: conflicting types for `prcdd_release'
prcdd.c:18: previous declaration of `prcdd_release'
prcdd.c: In function `prcdd_release':
prcdd.c:71: warning: implicit declaration of function `atomic_dec'
prcdd.c:71: union has no member named `usecount'
prcdd.c: At top level:
prcdd.c:26: storage size of `fops' isn't known

This is the source code,

#if defined(CONFIG_MODVERSIONS) && ! defined(MODVERSIONS)
#include <linux/modversions.h>
#define MODVERSIONS
#endif

#define _KERNEL_
#define MODULE

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <asm/uaccess.h>

//static int module_init(void);
//static void module_exit(void);
static int prcdd_open(struct inode *,struct file *);
static int prcdd_release(struct inode *,struct file *);

#define SUCCESS 0
#define DEVICE_NAME "prcdd"

static int Major;
static int Device_open = 0;

static struct file_operations fops = {
.owner = THIS_MODULE,
.open = prcdd_open,
.release = prcdd_release,
};

static int prcdd_init(void)
{
Major = register_chrdev(0,DEVICE_NAME,&fops);
if (Major < 0)
{
printk("Registering the character device failed with %d \n",Major);
return Major;
}

printk("<1>The assigned major number is %d \n",Major);
return 0;
}

static void prcdd_exit(void)
{
int ret = unregister_chrdev(Major,DEVICE_NAME);
if (ret < 0)
{
printk("Error in unregister_chrdev: %d \n",ret);
}
}

static int prcdd_open(struct inode *inode, struct file *file)
{
if (Device_open)
{
return -EBUSY;
}
Device_open++;

MOD_INC_USE_COUNT;
return SUCCESS;
}

static int prcdd_release(struct inode *inode, struct file *file)
{
Device_open--;

MOD_DEC_USE_COUNT;
return 0;
}

module_init(prcdd_init);
module_exit(prcdd_exit);

Any pointers on how to proceed from here?

Our company has something like 5000 of these modems on our devices in the field, and we need to support our customers.

Thanks - Phil Brooks, Philip.Brooks@DMXMusic.com

I got a problem proting device driver from 2.4 to 2.6, i.e. the asm/smplocak.h seems not in 2.6 kernel/include/asm, so could anyone help ?

Thanks

John

Thank you!

i am new to device driver can any body tell me how to access the device file...exactly i need to access the harddisk inforamation at block level..or else can u tell where i can get the information about this plz

Some random comments...

• Have you thought of updating the articles (perhaps letting others do the (re)writing)? Some have comments indicating that updates are in order.
• What about a cleanup of the comments? Most ones I see here aren't really about the subject matter, and are definitely useless for "longer term reference"...

Many thanks!