Re: [QUESTION] I have a question about making device driver

[Jiri Slaby]

On 02/05/2008 10:39 AM, ohyama_sec@xxxxxxxxxxxxxxxxxx wrote:
> > > --- check program ---
> > > #include <linux/types.h>
> > > #include <asm/io.h>
> > > #include <stdio.h>
> > A userspace program? I thought this was about kernel device drivers.
>
>
> Yes, It is a userspace program to see what I can write parallel port device controller or not.
>
> And, I'm sorry , I should not have explained my device driver in text, but should have written source code.
> So that, the following is source code of the device driver. It works only to obtain I/O resource (I/O address and IRQ).
>
>
> > > int main(void){
> > >    int base = 0x378;
> > >    char read, write;
> > >
> > >    ioperm(base, 1, 1);

if (ioperm(...)) {
	perror("ioperm");
	return 1;
}

and retest.

> > >    write = 0xa;
> > >    outb(write, base);
> > >    read = inb(base);
> > >    if((read & 0xf) == write){
[...]
> --- kernel module (device driver) ---
[...]
> #define SHORT_NR_PORTS	8	
>
> static int major = 0;	
>
> unsigned long short_base = 0x378;
>
> volatile int short_irq = 7;
> static struct cdev *obj_cdev;
>
> MODULE_AUTHOR ("hiroyasu ohyama");
> MODULE_LICENSE("GPL2");
>
> struct file_operations my_fops = {
> 	.owner	 = THIS_MODULE,
> };
>
> irqreturn_t short_sh_interrupt(int irq, void *dev_id, struct pt_regs *regs)
> {
> 	printk(KERN_INFO "interrupt\n");
>
> 	return 0;
> }
>
> int short_init(void)
> {
> 	int result;
> 	int err;
> 	int dev_num;
> 	dev_t dev;
>
> 	if (! request_region(short_base, SHORT_NR_PORTS, "hiro_test")) {
> 		printk(KERN_INFO "can't get I/O port address 0x%lx\n",
> 				short_base);
> 		return -ENODEV;
> 	}
>
> 	alloc_chrdev_region(&dev, 0, 1, "hiro_test");

why do you register chrdev?

> 	major = MAJOR(dev);
> 	
> 	dev_num = MKDEV(major, 0);
>
> 	obj_cdev = cdev_alloc();
> 	cdev_init(obj_cdev, &my_fops);
> 	obj_cdev->owner = THIS_MODULE;
> 	obj_cdev->ops = &my_fops;
> 	err = cdev_add(obj_cdev, dev_num, 1);
> 	if(err){
> 		printk(KERN_INFO "err_num : %d", err);	
> 	}
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