These boards were meaning to deploy this value:
#define LCRR_DBYP 0x80000000
but were missing a zero, and hence toggling a bit that
lands in an area marked as reserved in the 8548 reference
manual.
According to the documentation, LCRR_DBYP should be used as:
PLL bypass. This bit should be set when using low bus
clock frequencies if the PLL is unable to lock. When in
PLL bypass mode, incoming data is captured in the middle
of the bus clock cycle. It is recommended that PLL bypass
mode be used at frequencies of 83 MHz or less.
So the impact would most likely be undefined behaviour for
LBC peripherals on boards that were running below 83MHz LBC.
Looking at the actual u-boot code, the missing DBYP bit was
meant to be deployed as follows:
Between 66 and 133, the DLL is enabled with an
override workaround.
In the future, we'll convert all boards to use the symbolic
DBYP constant to avoid these "count the zeros" problems, but
for now, just fix the impacted boards.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Paul Gortmaker
1667013ddf