mx6ul_14x14_evk: Pass refsel and refr fields to avoid hang
authorFabio Estevam <fabio.estevam@nxp.com>
Mon, 29 Aug 2016 23:37:16 +0000 (20:37 -0300)
committerStefano Babic <sbabic@denx.de>
Tue, 6 Sep 2016 16:22:48 +0000 (18:22 +0200)
commit7dbda25ecd6d7cba13d29161675309ca43e3ba12
treed4b74d4f5163b2a6d30d67314e32f56c113dfdd7
parentedf0093732225c2fd0791c3864e9a3eef1f92f19
mx6ul_14x14_evk: Pass refsel and refr fields to avoid hang

When running a NXP 4.1 kernel with U-Boot mainline on a mx6ul-evk,
we observe a hang when going into the lowest operational point of cpufreq.

This hang issue does not happen on the NXP U-Boot version.

After comparing the SPL DDR initialization against the DCD table
from NXP U-Boot, the key difference that causes the hang is the
MDREF register setting:

DATA 4 0x021B0020 0x00000800

,which means:

REF_SEL = 0 --> Periodic refresh cycle: 64kHz
REFR = 1 ---> Refresh Rate - 2 refreshes

So adjust the MDREF initialization for mx6ul_evk accordingly
to fix the kernel hang issue at low bus frequency.

Reported-by: Eric Nelson <eric@nelint.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Eric Nelson <eric@nelint.com>
board/freescale/mx6ul_14x14_evk/mx6ul_14x14_evk.c