Re: [PATCH] HPET driver

[Jeff Garzik]

Andrew Morton wrote:
> Jeff Garzik <jgarzik@xxxxxxxxx> 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.

Thus I think only VM_RESERVED is needed...

	Jeff



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