Re: [PATCH] HPET driver

[Jeff Garzik <jgarzik@pobox.com>]

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.

Thus I think only VM_RESERVED is needed...

	Jeff