the following patch was just integrated into master: commit aee444f453f38e53f3e2ac54b560707616767869 Author: David Hendricks dhendrix@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For historical reference, the original U-Boot code seems to have worked basically by accident here.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@chromium.org Signed-off-by: David Hendricks dhendrix@chromium.org Reviewed-on: http://review.coreboot.org/3121 Reviewed-by: Ronald G. Minnich rminnich@gmail.com Reviewed-by: Stefan Reinauer stefan.reinauer@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@coreboot.org at Tue Apr 23 02:05:50 2013, giving +2 See http://review.coreboot.org/3121 for details.
-gerrit