On Wed, Aug 6, 2008 at 4:28 PM, Benjamin Herrenschmidt <[EMAIL PROTECTED]> wrote: > >> there is a bunch of error checking and difference in semantics that >> you need to fix. I think introduce a new API for this is silly, >> especially since we expect there to only be one actual invocation of >> the API for serial console access. > > Not necessarily.... > > There's another aspect to BAT mappings here. First, they should be > permanent (ie, not unmappable). That way, we have ioremap just use > an existing BAT mapping when asked for a device that is covered > by a BAT. This allows to have platform code do something like setup > a BAT over a bunch of SOC registers or over a device, to automagically > get drivers doing ioremap to that area benefit from it.
Actually, that is exactly what I am in the process of doing right now for all the 5200 platforms. It is a performance win with no apparent downside. Next I want to investigate if it makes sense to do it for PCI IO regions. g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
