Call to ioctl() on a usb device using usbfs does not work - linux

Question

I am trying to create my own driver for my Gamepad right now, I found out the original reason why I wanted to create it does not exist but I still want to do it for the experience. So please don't tell me there is a better way to do this than writing my own driver.
The part in kernelspace with the ioctl function that should be called is:
static int xpad_ioctl (struct usb_interface *intf, unsigned int code,void *buf) {
//struct usb_xpad *xpad = usb_get_intfdata(intf);
printk(KERN_INFO"(Ongy)IOCTL called\n");
//if (_IOC_TYPE(code) != XPAD_IOMAGIC) return -ENOTTY;
//if (_IOC_NR(code) > XPAD_IOMAX) return -ENOTTY;
switch(code){
case XPAD_IORMAP:
printk(KERN_INFO"(Ongy)IORMAP called\n");
break;
default:
return -EINVAL;
}
return 0;
}
static struct usb_driver xpad_driver =
{
.name = "Cyborg-V5-driver",
.probe = xpad_probe,
.disconnect = xpad_disconnect,
.unlocked_ioctl = xpad_ioctl,
.id_table = xpad_table,
};
The part in userspace to call it is (this is part of a Qt-application):
int openfile() {
char *device = "/dev/bus/usb/005/009";
printf("Opening device %s\n", device);
return open(device, /*O_RDONLY*/O_WRONLY | O_NONBLOCK );
}
[...] the closefile(int file_desc) is missing here, this and the openfile functions exist because of me not knowing one can call "::open()" when Qt overrides function calls.
void MainContainer::callioctl() {
int file_desc, ret_val;
errno = 0;
file_desc = openfile();
if (file_desc==-1){
printf("Ioctl notcalled because of: error %s\n", strerror(errno));
}
else
{
errno = 0;
//struct usbdevfs_getdriver* driver = (usbdevfs_getdriver*)malloc(sizeof(struct usbdevfs_getdriver));
struct mappingpair* pair = (mappingpair*)malloc(sizeof(struct mappingpair));
ret_val = ioctl(file_desc, XPAD_IORMAP, pair);
//printf("Drivername %s\n", driver->driver);
closefile(file_desc);
if (ret_val==-1) printf("Ioctl failed with error %s\n", strerror(errno));
else printf("Ioctl call successfull\n");
}
}
ok, the string to the file I open I get with a call to lsusb and change it by hand in the code, this is only for debugging and until I get the ioctl calls working
When I call the callioctl() it prints:
Ioctl failed with error Unpassender IOCTL (I/O-Control) für das Gerät
The German part means "wrong ioctl (I/O-Control) for the device" and nothing appears in dmesg, that is why I think my ioctl function in the driver is not called.

Answer 1

If you look at http://www.hep.by/gnu/kernel/usb/usbfs.html it says that to send an ioctl to the usb_driver device you need to do:
struct usbdevfs_ioctl {
int ifno;
int ioctl_code;
void *data;
};
/* user mode call looks like this.
* 'request' becomes the driver->ioctl() 'code' parameter.
* the size of 'param' is encoded in 'request', and that data
* is copied to or from the driver->ioctl() 'buf' parameter.
*/
static int
usbdev_ioctl (int fd, int ifno, unsigned request, void *param)
{
struct usbdevfs_ioctl wrapper;
wrapper.ifno = ifno;
wrapper.ioctl_code = request;
wrapper.data = param;
return ioctl (fd, USBDEVFS_IOCTL, &wrapper);
}
The documentation is listing usb device under /proc/bus so admittedly this may have changed.