[coreboot-gerrit] Patch merged into coreboot/master: 83d1ba7 tegra: i2c: Add a timeout to I2C bit clear recovery mechanism

[gerrit at coreboot.org]

the following patch was just integrated into master:
commit 83d1ba7e3da62a7860f7884a30212bd2a2bc8ab6
Author: Julius Werner <jwerner at chromium.org>
Date:   Fri May 16 11:27:46 2014 -0700

    tegra: i2c: Add a timeout to I2C bit clear recovery mechanism
    
    Our tests with the I2C bit clear mechanism (recovering from "lost
    arbitration" errors) show that the bit clear hardware does not work
    correctly in some situations. When a wedged slave device tries to send
    more than one 0-to-1-to-0 transition to the host (e.g. leftover bits
    from an aborted read), the controller never transitions the BC_ENABLE
    bit back to zero.
    
    This patch adds a long timeout to the bit clear code that waits for
    register transitions as a safeguard. This way, We will still eventually
    exit the function (probably followed by a reboot). Our tests show that
    this will recover from all conditions after at most a few reboots.
    
    BRANCH=nyan
    BUG=chrome-os-partner:28323
    TEST=Ran wedge_ack and wedge_read tests with software_i2c patch, system
    recovered as expected in all cases.
    
    Original-Change-Id: I6c37119130e1240e1ef3a5944582abbcd2e39ff0
    Original-Signed-off-by: Julius Werner <jwerner at chromium.org>
    Original-Reviewed-on: https://chromium-review.googlesource.com/200265
    Original-Reviewed-by: Tom Warren <twarren at nvidia.com>
    Original-Reviewed-by: Gabe Black <gabeblack at chromium.org>
    (cherry picked from commit 4c8d0af25cf107a38c856b38067b8f2f74384f22)
    Signed-off-by: Marc Jones <marc.jones at se-eng.com>
    
    Change-Id: I600d5c9a8e68719cf8795c083c5fac63f626f5bf
    Reviewed-on: http://review.coreboot.org/7948
    Tested-by: build bot (Jenkins)
    Reviewed-by: David Hendricks <dhendrix at chromium.org>


See http://review.coreboot.org/7948 for details.

-gerrit