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>

diff --git a/board/freescale/mx6ul_14x14_evk/mx6ul_14x14_evk.c b/board/freescale/mx6ul_14x14_evk/mx6ul_14x14_evk.c
index 32953aea2bb4b1ee4f83dfd5b296b00b23a0a5ad..126e499f923d00330dde28b62b003c63b645307e 100644 (file)
--- a/board/freescale/mx6ul_14x14_evk/mx6ul_14x14_evk.c
+++ b/board/freescale/mx6ul_14x14_evk/mx6ul_14x14_evk.c
@@ -804,8 +804,8 @@ struct mx6_ddr_sysinfo ddr_sysinfo = {
        .sde_to_rst = 0x10,     /* 14 cycles, 200us (JEDEC default) */
        .rst_to_cke = 0x23,     /* 33 cycles, 500us (JEDEC default) */
        .ddr_type = DDR_TYPE_DDR3,
-       .refsel = 1,    /* Refresh cycles at 32KHz */
-       .refr = 7,      /* 8 refresh commands per refresh cycle */
+       .refsel = 0,    /* Refresh cycles at 64KHz */
+       .refr = 1,      /* 2 refresh commands per refresh cycle */
 };
 
 static struct mx6_ddr3_cfg mem_ddr = {