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    SubjectRe: [PATCH] HPET driver
    On Thu, May 13, 2004 at 07:49:22PM -0400, Jeff Garzik wrote:
    > Andrew Morton wrote:
    > >Jeff Garzik <jgarzik@pobox.com> wrote:
    > >
    > >>>+ vma->vm_flags |= (VM_IO | VM_SHM | VM_LOCKED);
    > >>>+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
    > >>>+ addr = __pa(addr);
    > >>
    > >>where did these flags come from? don't you just want VM_RESERVED?
    > >
    > >
    > >VM_IO is the way to mark mmapped I/O devices.
    > >
    > > vma->vm_flags |= VM_IO;
    > >
    > >should be sufficient here.
    > >
    > >hm, I'm trying to decrypt how the driver accesses the hardware. It's
    > >taking copies of kernel virtual addresses based off hpet_virt_address, but
    > >there are no readl's or writel's in there. Is the actual device access
    > >done over in time_hpet.c?
    >
    >
    > HPET writes into RAM at magic addresses, so it's not really a bus address.

    Since it lives in the bridge (either north or south), IMO it is a bus
    address ... at least on AMD machines it's the same space where MMIO
    comes from.

    > Thus I think only VM_RESERVED is needed...
    >
    > Jeff

    --
    Vojtech Pavlik
    SuSE Labs, SuSE CR
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