On Thu, 27 May 2010, David Young wrote: > On Thu, May 27, 2010 at 05:20:03PM +0000, Eduardo Horvath wrote: > > On Thu, 27 May 2010, David Young wrote: > > > > > On Thu, May 27, 2010 at 04:28:19PM +0000, Eduardo Horvath wrote: > > > > On Thu, 27 May 2010, David Young wrote: > > > > > You would not use flags, you would install an override function to be > > > > > used instead of bus_space_read_4(). > > > > > > > > Uh, no you wouldn't. Endianness is set by MMU mappings when the > > > > registers > > > > are mapped in. Using the bswap routines on sparc64 is extremely > > > > inefficient since they result in 4-8 dependent instructions vs 0 cycles > > > > using the mux in the load/store path. > > > > > > You could also override bus_space_map() or whichever routine is most > > > suitable. (Did I mention that I've split bus-space reservations and > > > mappings? :-) > > > > > > Maybe you should have a look at stp4020.c to see if the le32toh() call > > > in stp4020_read_4() can be avoided. > > > > So... funky_bus.c calls bus_space_tag_create() then bus_space_map() to map > > in its regsiters. At what point do you override the but_space_map() > > routine? I'm still trying to understand how this is supposed to work for > > anything other than x86. > > Eduardo, > > Does this problem arise in any MI code that you are aware of?
No. But no MI code I'm aware of fiddles with bus_space_tags. Those are set up by MD code and passed in to MI routines which only use them. I'm a bit concerned about what could happen once MI code starts messing around with what was carefully crafted by MD code without the MD code being aware of it. Eduardo
