[U-Boot] [PATCH] ARM: imx6: Disable DDR DRAM calibration DHCOM i.MX6 PDK

[Marek Vasut]

On 12/11/2017 04:23 PM, Fabio Estevam wrote:
> Hi Marek,

Hi!

> On Mon, Dec 11, 2017 at 1:19 PM, Marek Vasut <marex at denx.de> wrote:
>> The DDR DRAM calibration doesn't work on T-topology sometimes, so disable it.
>>
>> Signed-off-by: Marek Vasut <marex at denx.de>
>> Cc: Stefano Babic <sbabic at denx.de>
>> ---
>>  board/dhelectronics/dh_imx6/dh_imx6_spl.c | 4 ----
>>  1 file changed, 4 deletions(-)
>>
>> diff --git a/board/dhelectronics/dh_imx6/dh_imx6_spl.c b/board/dhelectronics/dh_imx6/dh_imx6_spl.c
>> index bb98f39f02..57ae7f15ce 100644
>> --- a/board/dhelectronics/dh_imx6/dh_imx6_spl.c
>> +++ b/board/dhelectronics/dh_imx6/dh_imx6_spl.c
>> @@ -387,10 +387,6 @@ void board_init_f(ulong dummy)
>>                                   &dhcom6sdl_grp_ioregs);
>>         mx6_dram_cfg(&dhcom_ddr_info, &dhcom_mmdc_calib, &dhcom_mem_ddr);
>>
>> -       /* Perform DDR DRAM calibration */
>> -       udelay(100);
>> -       mmdc_do_dqs_calibration(&dhcom_ddr_info);
> 
> I also observed mmdc_do_dqs_calibration() failures and after applying
> this patch from Eric they were gone:
> https://lists.denx.de/pipermail/u-boot/2016-November/271596.html
> 
> Does this help to solve the mmdc_do_dqs_calibration() on your case too?

Nope, I'm not getting calibration failures, I'm getting bitflips at
runtime IFF I use the calibration. The calibration itself passes just fine.

-- 
Best regards,
Marek Vasut