Disable cache on 74xx

Gary Thomas gary at mlbassoc.com
Thu Feb 20 09:48:50 EST 2003

On Wed, 2003-02-19 at 14:07, Benjamin Herrenschmidt wrote:
> On Wed, 2003-02-19 at 21:52, Brian Waite wrote:
> > Hi all,
> > 	I am trying to hunt down a memory controller configuration problem and I have
> > been asked to disable all caching so as to remove it from the equation. I can
> > easl disable L2 but when I start ucking with the WIMG bits to set cache
> > inhibit, The kernel panics with stack overflows. Does anyone know where or
> > what I have to set to disable caching?
> Hrm... set L2 and L3 off, then hack HID0 to disable L1 ?

There are other problems with this.  With the caches disabled
(via HID0) all data cache instructions (like DCBF) will fail.
There are some of these in the kernel itself, but beware that
GLIBC has it's own set.

... totally disabling the data CACHE with Linux is non-trivial.

Gary Thomas                 |
MLB Associates              |  Consulting for the
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