[PATCH u-boot-marvell RFC] PLEASE TEST: ddr: marvell: a38x: fix BYTE_HOMOGENEOUS_SPLIT_OUT decision

[Marek Behún]

On Wed, 16 Feb 2022 09:41:44 +0100
Stefan Roese <sr at denx.de> wrote:

> On 2/15/22 23:21, Chris Packham wrote:
> > On Fri, Feb 11, 2022 at 5:25 AM Marek Behún <kabel at kernel.org> wrote:  
> >>
> >> From: Marek Behún <marek.behun at nic.cz>
> >>
> >> In commit 3fc92a215b69 ("ddr: marvell: a38x: fix SPLIT_OUT_MIX state
> >> decision") I ported a cleaned up and changed version of patch
> >>    mv_ddr: a380: fix SPLIT_OUT_MIX state decision
> >>
> >> In the port we removed checking for BYTE_HOMOGENEOUS_SPLIT_OUT bit,
> >> because:
> >> - the fix seemed to work without it
> >> - the bit was checked for only at one place out of two, while the second
> >>    bit, BYTE_SPLIT_OUT_MIX, was checked for in both cases
> >> - without the removal it didn't work on Allied Telesis' x530 board
> >>
> >> We recently had a chance to test on more boards, and it seems that the
> >> change needs to be opposite: instead of removing the check for
> >> BYTE_HOMOGENEOUS_SPLIT_OUT from the first if() statement, the check
> >> needs to be added also to the second one - it needs to be at both
> >> places.
> >>
> >> With this change all the Turris Omnia boards I have had available to
> >> test seem to work, I didn't encounter not even one failed DDR training.
> >>
> >> As last time, I am noting that I do not understand what this code is
> >> actually doing, I haven't studied the DDR training algorithm and
> >> I suspect that no one will be able to explain it to U-Boot contributors,
> >> so we are left with this blind poking in the code with testing whether
> >> it works on several boards and hoping it doesn't break anything for
> >> anyone :-(.
> >>
> >> Signed-off-by: Marek Behún <marek.behun at nic.cz>  
> > 
> > Tested-by: Chris Packham <judge.packham at gmail.com>  
> 
> Reviewed-by: Stefan Roese <sr at denx.de>

Dear Stefan,

will you apply this (removing the PLEASE TEST: prefix) or should I send
it again without it?

I am going to send another patch which will reset the board immediately
if DDR training fails, so I can send with that one.

Marek