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FWD: [ECOS] Problem with PowerPC cache init order

Hi Folks

Could somebody who knows about PPC caches take a look at this patch.


----- Forwarded message from "Retallack, Mark (Siemens)" <> -----

From: "Retallack, Mark (Siemens)" <>
Date: Mon, 14 Jun 2004 13:50:04 +0100
Subject: [ECOS] Problem with PowerPC cache init order
X-Spam-Status: No, hits=-4.7 required=5.0 tests=AWL,BAYES_00 autolearn=ham 

I have found a problem with the PowerPC architecture hal. 

The sequence for cache initialisation after reset (in hal_enable_caches)
should be:

unlock all
invalidate all
enable cache

Instead it is:

invalidate all
unlock all
enable cache

This can cause problems if there are sections of the cache that are locked
and contain invalid data. My target crashed with an exception when it needed
to do a copyback after a first time power up (not a pretty sight!!). The
copyback address was an invalid address.

I have attached a patch to fix the problem. This works for the MPC850, but I
do not know if it is correct for the complete PowerPC family.


Mark Retallack
Graduate Engineer
Siemens Traffic Controls 
Sopers Lane, Poole, Dorset. BH17 7ER. UK.
Tel: 01202 782844
Fax: 01202 782545

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