[U-Boot-Users] MMU setup in u-boot
Chris Hallinan
clh at net1plus.com
Mon May 12 17:13:30 CEST 2003
> On Mon, May 12, 2003 at 11:23:55AM -0230, john ashfield wrote:
> > u-boot setups MMU for maximum of 256M memory using Block Address
> > Translation. Do you have any idea how to setup MMU for
> more than 256M
> > (for example 1G of memory)?
>
> Hmm, normally the MMU is not used in U-Boot at all! This
> should be the
> task of the kernel (or whatever you boot).
>
Actually, I/DBATS *are* part of the MMU. :) They are simply *one*
of the translation mechanisms provided by the PPC architecture!!
The MMU is enabled in start.S for 824x like this:
/*
* Setup BATs - cannot be done in C since we don't have a stack yet
*/
bl setup_bats
/* Enable MMU.
*/
mfmsr r3
ori r3, r3, (MSR_IR | MSR_DR)
mtmsr r3
Regards,
Chris Hallinan
DS4.COM, Inc.
More information about the U-Boot
mailing list