[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    For historical reference, the original U-Boot code seems to have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.


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