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

[Marek Vasut]

On Sunday, January 24, 2016 at 06:03:52 PM, Stefano Babic wrote:
> Hi Marek,
> 
> On 24/01/2016 17:01, Marek Vasut wrote:
> > On Sunday, January 24, 2016 at 11:47:56 AM, Stefano Babic wrote:
> >> 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.
> > 
> > This patch was not applied yet, but the conversion will be
> > straightforward once it is applied.
> 
> Yes, it is - then it is better to this before applying.

It is not clear when the wait_for_bit() will be applied, I am certain there
will be another round for so. I do not want to wait for it and I don't see
a reason why those patches should block this if the conversion can be done
afterward.

> > So, please apply these patches.
> 
> We are not hurry for the release, and I think we have time to make
> things right at once.

The shorter they will be in the tree, the less testing they will have.

Best regards,
Marek Vasut