[U-Boot-Users] MMU setup in u-boot

[Chris Hallinan]

> 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.