cmfai...@rockwellcollins.com wrote: > Hi, > I am wondering what the ramifications of not using the MMU in U-Boot are? > I have an MPC8360 (e300 core) where it is capable of disabling the MMU via > the MSR[IR] and MSR[DR] bits. > > Before disabling the MMU, I'm just wondering why U-Boot bothers to set up > the MMU on CPU's that providing disabling of the MMU.
A big one is that you can't have certain regions be cached (memory) and others uncached (I/O) -- you'll need to turn the D-cache off altogether. And even then I'm not sure what happens to the guarded bit when the MMU is off. > I'm not disabling the MMU just for kicks, there are/may be some > program-specific scenarios where I may need to use the option of disabling > the MMU. Such as? One should generally lead with the reason they want to do something, and only afterwards ask "why not". :-) -Scott _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
