[parisc-linux] Astro and 100BT still not working

[Bob Pflederer]

On Tue, Apr 11, 2000 at 11:08:16PM -0700, Grant Grundler wrote:
> 
>     For I/O PDIR fetches themselves, IKE assumes that the I/O PDIR is
>     equivalently mapped. I.e., it assumes that the physical address =
>     virtual address and so it supplies bits 19:12 of the physical address
>     as the virtual index. To ensure coherency of I/O PDIR fetches, the
>     I/O PDIR must be equivalently mapped.
> 
> 
> The second paragraph worries me. It suggests parisc-linux has to flush
> the cachelines which contain I/O Pdir data every time such data is
> changed since it's not equivalently mapped.  Since only bits 31:28
> are different for kernel space (0xc....), does this still apply?
> 
No.  Only bits 19:12 of the virtual address need to match bits 19:12 of the 
physical address.  You may need to use space=0 for your virtual address 
because of the CPU's space hashing feature.