Device driver registration problem

["Ivan Korzakow" <ivan.korzakow@xxxxxxxxx>]

Hi,

I've been unable to solve this problem, so if anyone has an idea, I'll
be really happy to have some hints ! Here is the issue :

I'm writing a device driver which is made of two layers : the
"generic" part containing all the file operations and other
initialization stuff, and a "specific" part (depending on the
hardware) which is a module that register into the generic layer at
init time. Here is a part of that registration function (you can
register several devices at a time) :

int register(struct params *some_params)
{
	int i, result = 0;
	struct device_descr *my_device;

	/* allocate minor numbers for the device */
	result = register_chrdev_region(MKDEV(MY_MAJOR,some_params->from),
					some_params->number, "my_driver");
	if (result) {
		printk(KERN_ERR \
		       "Device number registration failed\n");
		goto out;
	}

	/* Create and initialize the device structures */
	for(i = some_params->from ; i <=  some_params->to; i++) {
		my_device = (struct device_descr *) \
		    kzalloc(sizeof(struct device_descr), GFP_KERNEL);
		if (!my_device) {
			result = -ENOMEM;
			goto out;
		}
		/* Initialize the devices */
		[...]

		init_device(my_device);
	}
out:
	return resutl;
}

and in the init_device function, I'm doing :

static void init_device(struct device_descr *dev)
{
	int err = 0;
	dev_t devno = MKDEV(MY_MAJOR, dev->devnum);

	/* Register cdev */
	cdev_init(&dev->my_cdev, &my_fops);
	err = kobject_set_name(&dev->my_cdev.kobj, dev->name);
	if (err)
		goto err;

	dev->my_cdev.owner = THIS_MODULE;
	dev->my_cdev.ops = &sci_fops;
	err = cdev_add(&dev->myi_cdev, devno, 1);
	if (err)
		goto err;
	else
		return;
	
 err:
	printk(KERN_ERR "Error %d while adding %s", err, dev->name);
}

After this (long) introduction, my problem : when i am registering
several devices, only device 0 is working, that is to say, when
opening /dev/my_device0, the open function of my driver is called. But
for all the other device numbers, I get the error "No such device or
address".

I really don't see where the problem comes from. I checked with the
debugger that the initialization is ok for each device.
Is it problematic that I call register_chrdev_region and cdev_add not
during module_init but after ?

Thanks in advance for any idea,

Ivan

--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive:       http://mail.nl.linux.org/kernelnewbies/
FAQ:           http://kernelnewbies.org/faq/