On 26/06/2010, at 3:01, Christopher Bowman wrote: > I have a Xilinx PCI Express board that has an on board PCIe interface > macro. I intend to have an address space with memory and another with my > devices control registers. I wish to program this board under FreeBSD. It > would seem to me that the way to do this would be to write a driver that > would allow me to map these two address spaces into a user process which > could then directly interact with the device. In my case my board doesn't > really support multiple users, and it doesn't really seem to make sense to > me to put a lot of code in the kernel to create some sort of interface to > allow multiple processes to interact with my device via some sort of syscall > which would impose a lot of overhead in any case. By mapping the address > ranges into a user process I can write user programs to drive the board > without having to recompile and reboot the kernel each time I make a change, > plus if I do something stupid and crash my user space process it shouldn't > bring down the whole kernel. Am I thinking about this wrong? Is there some > place I can go to read up on what I should be doing? If I am thinking about > this correctly, then how does one map device memory into a user space > process? How does one make sure that only one process has such a mapping?
You could use mmap() I think, For a driver I maintain I did the following -> /* Magic sauce stolen from src/sys/pci/xrpu.c via phk * http://www.mail-archive.com/freebsd-hackers%40freebsd.org/msg11729.html */ *paddr = rman_get_start(sc->g_membase.reshandle) + offset; g_membase is.. struct resource *reshandle; /* Resource handle */ bus_space_tag_t sc_st; /* bus space tag */ bus_space_handle_t sc_sh; /* bus space handle */ PS what board are you using? :) -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
