try using alloc_chrdev_region,,
-Vamsi
-----Original Message-----
From: kernelnewbies-bounce@xxxxxxxxxxxx on behalf of Ivan Korzakow
Sent: Mon 4/3/2006 2:40 PM
To: kernelnewbies@xxxxxxxxxxxx
Subject: Device driver registration problem
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
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