The Allwinner A64 SoCs suffers from an arch timer implementation erratum,
where sometimes the lower 11 bits of the counter value erroneously
become all 0's or all 1's [1]. This leads to sudden jumps, both forwards and
backwards, with the latter one often showing weird behaviour.
Port the workaround proposed for Linux to U-Boot and activate it for all
A64 boards.
This fixes crashes when accessing MMC devices (SD cards), caused by a
recent change to actually use the counter value for timeout checks.
Fixes: 5ff8e54888 ("sunxi: improve throughput
in the sunxi_mmc driver")
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-May/576886.html
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Andreas Färber <afaerber@suse.de>
Tested-by: Guillaume Gardet <guillaume.gardet@free.fr>
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