[Info-vax] Device Driver Kernel-User Buffer Mapping

[Luigi Thirty]

Hi,

I’m a hobbyist with an AlphaServer DS10 running 8.4. I have a certain PCI card that I’m writing a driver for as a project.

The card uses 16MB of linear address space in the PCI segment and no I/O space. I’ve used IOC$MAP_IO to map it into virtual memory and can access the card’s memory space from the kernel context no problem. I have read and write QIO commands hooked up as well which a user process can call.

What I would like to do, though, is make the PCI memory buffer directly accessible from a user process that’s opened a channel to the device and made a request for it. In Linux this would be mmap() with a shared buffer, in NT this would be IOCTL_MAPMEM_USER_PHYSICAL_MEMORY but I can’t find the equivalent in the VMS documentation.

Any ideas?

Katherine