[coreboot-gerrit] Patch merged into coreboot/master: aee444f exynos5250: ungate the product ID register
gerrit at coreboot.org
gerrit at coreboot.org
Tue Apr 23 03:20:49 CEST 2013
the following patch was just integrated into master:
commit aee444f453f38e53f3e2ac54b560707616767869
Author: David Hendricks <dhendrix at chromium.org>
Date: Mon Apr 22 16:03:11 2013 -0700
exynos5250: ungate the product ID register
This makes sure that the product ID (PRO_ID) register can be read
when the OS kernel is figuring out what kind of CPU it's running on.
For historical reference, the original U-Boot code seems to have
worked basically by accident here. The hardware has a quirk where by
reading the value before gating the IP block keeps the value
persistent. U-Boot reads the chip ID early on to distinguish between
chip family, but we do not mix code the same way so we do not read
the chip ID. Since the value has been read before the clock gating
happens, the value remains available for the kernel to use during the
decompression stage. We don't want to rely on that behavior when using
coreboot. Instead the kernel should gate unused IPs.
(credit to Gabe for finding symptom in the kernel)
Change-Id: Iaa21e6e718b9000b5558f568020f393779fd208e
Signed-off-by: Gabe Black <gabeblack at chromium.org>
Signed-off-by: David Hendricks <dhendrix at chromium.org>
Reviewed-on: http://review.coreboot.org/3121
Reviewed-by: Ronald G. Minnich <rminnich at gmail.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer at coreboot.org>
Tested-by: build bot (Jenkins)
Build-Tested: build bot (Jenkins) at Tue Apr 23 03:06:56 2013, giving +1
Reviewed-By: Stefan Reinauer <stefan.reinauer at coreboot.org> at Tue Apr 23 02:05:50 2013, giving +2
See http://review.coreboot.org/3121 for details.
-gerrit
More information about the coreboot-gerrit
mailing list