On 2/16/22 14:26, Marek Behún wrote:
On Wed, 16 Feb 2022 09:41:44 +0100 Stefan Roese sr@denx.de wrote:
On 2/15/22 23:21, Chris Packham wrote:
On Fri, Feb 11, 2022 at 5:25 AM Marek Behún kabel@kernel.org wrote:
From: Marek Behún marek.behun@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@nic.cz
Tested-by: Chris Packham judge.packham@gmail.com
Reviewed-by: Stefan Roese sr@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.
Whatever you prefer. Plan is to apply/push some of the pending patches in the next few days.
Thanks, Stefan