Messages in this thread | | | Date | Mon, 14 Mar 2005 11:13:44 +1100 | From | Peter Chubb <> | Subject | Re: User mode drivers: part 2: PCI device handling (patch 1/2 for 2.6.11) |
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>>>>> "Greg" == Greg KH <greg@kroah.com> writes:
Greg> On Fri, Mar 11, 2005 at 07:34:46PM +1100, Peter Chubb wrote: >> >>>>> "Greg" == Greg KH <greg@kroah.com> writes: >> Greg> On Fri, Mar 11, 2005 at 02:37:17PM +1100, Peter Chubb wrote: >> >> +/* + * The PCI subsystem is implemented as yet-another pseudo >> >> filesystem, + * albeit one that is never mounted. + * This is >> its >> magic number. + */ +#define USR_PCI_MAGIC (0x12345678) >> Greg> If you make it a real, mountable filesystem, then you don't need Greg> to have any of your new syscalls, right? Why not just do that Greg> instead? >> >> >> The only call that would go is usr_pci_open() -- you'd still need >> usr_pci_map()
Greg> see mmap(2)
mmap maps a file's contents into your own virtual memory. usr_pci_map maps part of your own virtual memory into pci bus space for a particular device (using the IOMMU if your machine has one), and returns a scatterlist of bus addresses to hand to the device.
Different semantics entirely.
Greg> In fact, both of the above can be done today from /proc/bus/pci/ Greg> right?
Nope.
-- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au The technical we do immediately, the political takes *forever* - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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