hello,i recently debug an pci device,but when i try to use to syscall to read the config register i got an error bad address from the ioctl.
the code is below:
fd: fd=open("/dev/Plx/Plx9054",O_RDWR|O_NONBLOCK);
this code works well.
unsigned long args=1;
ioctl: i=ioctl(fd,PLX_IOCTL_CHIP_TYPE_GET,args);
the cmd PLX_IOCTL_CHIP_TYPE_GET is used to get the chip type of the pci device.It's defined in the PlxIoctl.h.(I used the PLX SDK to compile my pci driver)The args I don't know how to use it.so here i give it an one.But the syscall ioctl return an error bad address.what's wrong?
i trace the function ioctl defined in the pci drive.here is the code:
PLX_RET_IOCTL
Dispatch_IoControl(
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36))
struct inode *inode,
#endif
struct file *filp,
unsigned int cmd,
unsigned long args
)
{ int status;
VOID *pOwner;
PLX_PARAMS IoBuffer;
PLX_PARAMS *pIoBuffer;
DEVICE_EXTENSION *pdx;


DebugPrintf_Cont(("\n"));

// Get the device extension
if (iminor(filp->f_dentry->d_inode) == PLX_MNGMT_INTERFACE)
{
// Management interface node only supports some IOCTLS
pdx = NULL;
}
else
{
pdx = ((DEVICE_OBJECT*)(filp->private_data))->DeviceExtension;
}

// Copy the I/O Control message from user space
status =
copy_from_user(
&IoBuffer,
(PLX_PARAMS*)args,
sizeof(PLX_PARAMS)
);

if (status != 0)
{
ErrorPrintf((
"ERROR - Unable to copy user I/O message data\n"
));
}

of coure i also has been given an error unable to copy user I/O message data from the debug monitor.
But why? can any body help me ?

You need to create an object of type PLX_PARAMS and send its address as third argument to the ioctl, basically like this;

PLX_PARAMS args;

i=ioctl(fd,PLX_IOCTL_CHIP_TYPE_GET, &args);

Once the ioctl function is returned you will have your data in the args.

1 members found this post helpful.

ok,thanks.i will try it later.

i havd tried it.But it does not work,and returns an kernel panic.can andybody have ideas?