Messages in this thread | | | From | "David S. Miller" <> | Date | Fri, 2 Mar 2001 17:08:48 -0800 (PST) | Subject | Re: The IO problem on multiple PCI busses |
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Benjamin Herrenschmidt writes: > There is still the need, in the ioctl we use the "select" what need to be > mapped by the next mmap, to ask for the "legacy IO range of the bus where > the card reside" (if it exist of course). That would be the 0-64k (or less, > actually a couple of pages would probably be enough) that generates IO cycles > in the "low" addresses used for VGA registers on the card.
As I've stated in another email, this is perfectly fine and is precisely the kind of thing implied by my original proposal in this thread.
You can even have arch-specific "next mmap is" ioctl values to do "special things".
The generic part of the ioctl()/mmap() bits the PCI driver will have added won't care about these ioctl's all that much, the include/asm/pcimmap.h header will deal with all such details. This header is also where the physical address and the actual creation of the page table mappings will occur. The generic PCI code will only provide the skeletal parts of the mmap() method and call into the arch-specific hooks coded in asm/pcimmap.h
Later, David S. Miller davem@redhat.com - 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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