[U-Boot] iMX6 DDR Calibration Value

[John Tobias]

Hi Fabio,

I think I got it and here's what I did:

When the DDR stress tester generated those calibration settings, run
the stress test. Once the board (with micron) passed the stress test,
copy those settings and overwrite the value of those registers in the
.inc file.
Then, run the (ONLY) stress test again on different board (with
different DDR). Once it passed, the value that the stress tester
generated could use as a default value of those registers.

Regards,

John Tobias

On Fri, Nov 14, 2014 at 10:44 AM, Fabio Estevam <festevam at gmail.com> wrote:
> On Thu, Nov 13, 2014 at 11:19 PM, John Tobias <john.tobias.ph at gmail.com> wrote:
>> Hi Fabio / Stefano,
>>
>> May be you could help me to get some answer regarding with
>> calibrations value for DDR.
>>
>> I have a 4 custom boards based on iMX6SL (2) Micron DDR and (2) Samsung DDR.
>>
>> The boards has exact DDR footprints (like density, bus width and so
>> on). In fact the uboot that I am using works on both DDR chips.
>>
>> I re-ran the DDR tools twice for each boards, entered the same
>> information. The tools returned different calibration values for each
>> boards but, the two results for each boards were the same.
>>
>>
>> e.g: board1
>>
>> Read DQS Gating calibration
>> MPDGCTRL0 PHY0 (0x021b083c) = 0x412C0130
>> MPDGCTRL1 PHY0 (0x021b0840) = 0x01140118
>>
>> Read calibration
>> MPRDDLCTL PHY0 (0x021b0848) = 0x3E404244
>>
>> Write calibration
>> MPWRDLCTL PHY0 (0x021b0850) = 0x383C3E36
>>
>> board2:
>>
>>  Read DQS Gating calibration
>>  MPDGCTRL0 PHY0 (0x021b083c) = 0x412C0130
>>  MPDGCTRL1 PHY0 (0x021b0840) = 0x01140118
>>
>>  Read calibration
>>  MPRDDLCTL PHY0 (0x021b0848) = 0x3E3E4244
>>
>>  Write calibration
>>  MPWRDLCTL PHY0 (0x021b0850) = 0x383C3E36
>>
>> Is there any procedures or rules of thumb you follow dealing with the
>> calibration settings?.
>
> Then you need to provide a mx6_mmdc_calibration structure for each board, right?
>
> Take a look at gw_ventana_spl.c for an example on how this is done.
>
> Regards,
>
> Fabio Estevam