On Thu, 2009-11-26 at 22:38 +0100, Albert Herranz wrote: > Yup. The idea is to map the first 16MB of MEM1 with a BAT. > Mapping the whole 24MB with BATs may not be possible because we want the > framebuffer > in MEM1 for performance reasons.
How big is the fb ? We have plenty of BATs on these things... so one 16M for the low mem and one 64M for the "high" mem, that leaves something like 6 to manage as much as possible up to the fb :-) Let's keep 1 or 2 for debug and maybe even BAT map the fb itself, we still are quite comfortable :-) That reminds me we still need to re-introduce a clean version of io_block_mapping (or ioremap flag that does the same) so the platform code can establish a BAT mapping for a whole bunch of IOs and ioremap transparenty picks addresses in there. We used to do it, dropped it mostly because it was done badly (virtual address was hard coded which caused all sorts of issues) but it shouldn't be hard to do it right and it would improve perfs a little bit more. Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
