[U-Boot] [PATCH 1/2] arm: imx6: Add DDR3 calibration code for MX6 Q/D/DL

[Stefano Babic <sbabic@denx.de>]

Hi Tim, Marek, Fabio,

On 14/01/2016 15:25, Tim Harvey wrote:

> I was able to test the auto calibration a couple of weeks ago on a set
> of boards. I have a mix of boards with IMX6Q/IMX6DL 16/32/64bit
> 2/4/8Gb density - a pretty broad range. I did find the that a couple
> of my boards hung during mx6_dram_cfg if I skip writing anything to
> the calib registers (I made mx6_dram_cfg able to take a null struct
> mx6_mmc_calibration and call mmdc_do_write_level_calibration() and
> mmdc_do_dqs_calibration() automatically if null after config). I
> haven't had time to troubleshoot yet. Its possible I need some initial
> value for the calib registers or its possible there is a step in the
> init that should differ if we have not yet calibrated.
> 
> I am all for committing what we have (as its opt-in) and we can
> continue to improve/test/troubleshoot.

I was thinking about it and I agree that it is better to get it in and
goes on with tests, as we can achieve much more testers.

However, I have seen that there is a general attempt for a
wait_for_bit() function, posted here:

	http://patchwork.ozlabs.org/patch/572085/

This can help to drop the i.MX6 implementation and reuse a general utility.

Best regards,
Stefano Babic

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