[PATCH 22/26] imx8m: ddr: Disable CA VREF Training for LPDDR4

[Peng Fan (OSS)]

On 2021/3/25 16:14, Stefano Babic wrote:
> Hi Tim,
> 
> On 24.03.21 22:25, Tim Harvey wrote:
>> On Fri, Mar 19, 2021 at 12:31 AM Peng Fan (OSS) <peng.fan at oss.nxp.com> 
>> wrote:
>>>
>>> From: Ye Li <ye.li at nxp.com>
>>>
>>> Users reported LPDDR4 MR12 value is set to 0 during PHY training,
>>> not the value from FSP timing structure, which cause compliance test 
>>> failed.
>>> The root cause is the CATrainOpt[0] is set to 1 in 2D FSP timing
>>> but not set in 1D.  According to PHY training application node,
>>> to enable the feature both 1D and 2D need set this field to 1,
>>> otherwise the training result will be incorrect.
>>> The PHY training doc also recommends to set CATrainOpt[0] to 0 to use
>>> MR12 value from message block (FSP structure). So update the LPDDR4
>>> scripts of all mscale to clear CATrainOpt[0].
>>
>> Peng,
>>
>> Is this issue being addressed by an update of the NXP i.MX 8M Family
>> DDR Tools app that generates this code? Is there a reference to this
>> issue online anywhere?
>>
>> A bit unrelated but I would love to see NXP step up and replace the
>> silly NXP i.MX 8M Family DDR Tools windows app with code that could be
>> enabled in the SPL to do the same thing. Personally it's a bit of a
>> joke to require having a Windows PC around to bring up an ARM
>> processor board and I would hope there are folks at NXP that are
>> utterly ashamed at this as well. One could easily use the opensource
>> imx-usb-loader to load an SPL that performed this calibration and
>> training code.
> 
> You find a lot of friends here....most of us will frankly be glad if 
> there will be such as tool, or at least if some code is published to 
> help to port to Linux. NXP story did not show a big interest in the past 
> with the Windows-based MFGTools, but I hoped this was changed with 
> "uuu". Such as tool will really help to improve i.MX support and enlarge 
> NXP community (just a couple of notes: I do not expect Peng can decide 
> this, but he can report our thought internally to NXP).

I have forwarded Tim's to NXP internal. And will also add yours' 
comments about this DDR tool.

I am not the DDR guy, it is out of my power to do the convert, but I'll
try to sell your ideas.

Thanks,
Peng.

> 
> Best regards,
> Stefano
>