LinuxQuestions.org - Kernel driver for 2

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- - Kernel driver for 2 (https://www.linuxquestions.org/questions/linux-kernel-70/kernel-driver-for-2-a-4175631113/)

Kernel driver for 2

Hello,

The following code was copied from:
http://true-random.com/homepage/proj...pci_template.c

Code:



static struct file_operations _template_fops =

{

  .owner = THIS_MODULE,

  .read = _template_read,

  .write = _template_write,

  .open = _template_open,

  .release = _template_close,

};



static struct

pci_driver pci_drv_template =

{

  .name= "pci_drv_template",

  .id_table= pci_drv_ids,

  .probe= device_init,

  .remove= device_deinit,

};



static

int __init pci_drv_init(void)

{

  int i_result=0;



  printk (KERN_CRIT "pci_chrdev_template: initialising\n");

  

  // dynamic major number allocation

  rc = register_chrdev (0, "pci_chrdev_template", &_template_fops);

  if (rc< 0)

  {

      printk (KERN_CRIT "pci_chrdev_template: Cannot register device.\n");

      return (i_result);

  }

  printk ("major=%d

  rc=pci_register_driver (&pci_drv_template);

  if (rc < 0)

    return rc;



  return rc; 

}

Now I ran:
mknod /dev/pci_template0 c 248 0
mknod /dev/pci_template1 c 248 1

After opening "/dev/pci_template0", if I send IOCTL, how the kernel driver knows that I sent to minor=0 ?

Thank you,
Zvika

very generally speaking, the files in /dev/ are not disk files they are sockets in a special file system mounted by the kernel. the drivers read and write from them, and their (file attributes i believe) contain the major minor. the kernel only sends the data you use to a driver who (has opened) the same major minor socket via the kernel's open function.

Dear Members,

The solution I found (hope it's right):

In /dev I created 2 nodes:
mknod my0 c 248 0
mknod my1 c 248 1

In kernel I can extract the minor number with:

static int MyOpen (struct inode *inode, struct file *fl)
{
int Minor = MINOR (inode->i_rdev);
}

static long MyIoctl (strcut file *file, unsigned int IoctlCode, unsigned long IoctlParam)
{
int Minor = MINOR (file->f_inode->i_rdev);
}

In user space I open my? and send IOCTL to the driver.

Thank you,
Zvika