[U-Boot] [PATCH v3] powerpc: Restore core of mpc8xx

[Heiko Schocher]

Hello Christophe,

Am 22.06.2017 um 13:20 schrieb Christophe LEROY:
>
>
> Le 22/06/2017 à 11:59, Wolfgang Denk a écrit :
>> Dear Christophe,
>>
>> In message <0784ad6e-86ab-9c1d-1b81-a5cacaf2b01f at c-s.fr> you wrote:
>>>
>>>> Please see my previous comments to Tom's message.  At least, please
>>>> clean up the directory structure and get rid of unrelated (4xx) and
>>>> untested/broken code (bedbug, probably kgdb, pcmcia, usb).
>>>
>>> I got 4xx unrelated stuff out in v3, as mentioned above.
>>
>> I still see these files in your patch:
>>
>>     drivers/net/4xx_enet.c
>>     include/configs/CPCI4052.h
>>     include/configs/MIP405.h
>>     include/configs/PIP405.h
>>     include/configs/PLU405.h
>
> Those are
>
> #undef    CONFIG_IDE_8xx_DIRECT
>
> My patch brings back CONFIG_IDE_8xx_DIRECT, so if somebody has decided that this CONFIG_ shall
> explicitly be undefined for 4xx targets, I believe there is a reason and I cannot decide by myself
> to remove that.

That;s exactly a part of crap ... now, as this symbol is gone, no need
for it to undef it in some none 8xx configs ...

>> To me these look very much like PPC4xx related.  In addition, it
>> makes zero sense to keep PPC405 board config files without any
>> related board code.
>
> Why do you say that ? There is a lot of code in arch/powerpc/ppc4xx/ and in configs/ you find the
> following defconfigs:
> -rw-r--r--. 1 root root 641 Jun 22 01:34 CPCI4052_defconfig
> -rw-r--r--. 1 root root 871 Jun 22 01:34 MIP405_defconfig
> -rw-r--r--. 1 root root 799 Jun 22 01:34 MIP405T_defconfig
> -rw-r--r--. 1 root root 869 Jun 22 01:34 PIP405_defconfig
> -rw-r--r--. 1 root root 675 Jun 22 01:34 PLU405_defconfig
> -rw-r--r--. 1 root root 588 Jun 22 01:34 PMC405DE_defconfig
> -rw-r--r--. 1 root root 449 Jun 22 01:34 VOM405_defconfig
> -rw-r--r--. 1 root root 747 Jun 22 01:34 xilinx-ppc405-generic_defconfig

Actually I have the 4xx removal patches on my todo list, but did not
find time yet to submit these.  I hope I will find time for this
next week.  As far as the MPC8xx discussion is related, please
consider 4xx as removed, too.

>> On the other hand I do not see a single board configuration for 8xx,
>> so you cannot even compile the code for a MPC8xx board, or am I
>> missing something?
>
> Yes you are right, Tom asked me to bring back only the core part for the time being, until I have
> cleaned up the code for our two boards.

Ok... but should we not have at least one (minimal) board configuration
so you can at least build the code and see if it compiles?  Whithout
such test, the risk of broken, non-compiling code is huge!

>>>> Also, are you going to support the whole family, including MPC823(E)?
>>>> If not, we should also omit stuff like the 823 video support.
>>>
>>> I agree, but please no big-bang now. It is already complicated enough.
>>
>> I try to get used to the idea of doing code level cleanup later,
>> even though my personal feeling for re-adding known-to-be-broken
>> code is not exactly positive.
>>
>>
>> But at least at file level we should perform the needed cleanup now:
>> - omit unrelated stuff
>> - omit known to be unsupported/untested/broken code
>> - move drivers to the correct places according to today's file
>>    system hierarchy.
>>
>> As I explained before, I doubt that you will be able to test things
>> like  drivers/video/mpc8xx_lcd.c  on your boards, and I strongly
>> doubt that you are willing to invest efforts in adapting and testing
>> things like PCMCIA, bedbug, SIL680 support, or USB on your hardware.
>
> Yes I agree, that's probably the first things I will remove (except USB probably).

I am here in line with Wolfgang. Why bringing in code, you do not know
about, if you need it?

Make a list of features you need for your board and only add
this code. Or do you not know what you need?

>> [In which way is the sil680 driver related to mpx8xx, btw?]
>>
>>
>> So when we know in advance that this old, crappy code will never be
>> tested, why should we spend effforts even in adding it?
>
> Just because it was there 2 weeks ago. I prefer starting from a known situation.

???

The current (also known) situation is that we have no 8xx code in
mainline, and we are free to re-add the necessary things to their
correct locations - and omit everything where we do not know for
sure that it will really be needed in the future.  If later we lear
that something is still missing, this is more easy to add then,
instead of cleaning up again and removing unneeded parts.

>>> We have something that fits and that was unexpectedly removed entirely
>>> last week. Lets come back first to a well known - working situation and
>>> do the removal of unnecessary parts step by step as if we were 3 weeks
>>> ago. The more we wait to get 8xx back in, the more difficult it will be.
>>
>> To be frank: you don't have a very extensive track record of working
>> with the U-Boot community.  At the moment all we have is your claim
>> that you will care about 8xx in the furture.  In the past, we have
>> seen many precedents of "please add this code now, I know it is not
>> really good, but I will fix it later, promised" - and then the code
>> was in mainline, until somebody else digged into cleaning it up.
>
> Well, I don't know what to answer to that, I understand your reluctance but you probably also
> understand mine, I try crawling in one direction to get my boards in while others are removing more
> and more stuff (51xx, 82xx, 5xx ...) which makes the come back of 8xx more difficult each day.

And your solution is reverting none 8xx patches? Come on! Why is this a
problem for bringing 8xx back?

I do not understand you here ... you have the old core 8xx files, and you only
have to add them to the current base, and bring them up again to compile ...

yes it is work, here and there, because mpc82xx and mpc8xx code wasn't cleanly
separated, unexplainable undef of 8xx defines in 4xx related configs ...

Time to clean it up!

U-Boot code changes from day to day ... do you mean, we should stop
adding patches until you have your patches in?

If you are working on this right now in a private repository branched
from the current mainline tree, then it is really little effort to
rebase your work tree every few hours against the then current
mainline tree. The 8xx code is not used anywhere else, so you
should see only a few merge conflicts in Makefiles or Kconfig files
while you go, and all these would be trivial to fix.

Actually cleaning up before submitting should be less work for you
than re-adding the old cod now and cleaning it up in mainline later.
Not to mention that you can squash unneeded intermediate results in
your tree before the submission, so the patch series would even be
smaller and easier to review.

>> I've been using MPC8xx for 18 years, and I know all too well in how
>> many places the code is in urgent need of a cleanup (heck, I'm even
>> responsible for major parts of that mess - but those were the times
>> way back then).  I'm not sure if you already anticipate the size of
>> job you have taken.  Just looking at the POST code - are you aware
>> how much effort it will be to adapt it to your board and to test it?
>> And this is mandatory requirement if you want to have it added. It
>> must be maintained, i. e. tested.
>
> We have it running on our boards and it works, it is just not in a clean submittable (doesn't
> respect the Codying Style, has several hard coded stuff in core parts, etc ...), so I cannot submit

Ah! Now we came closer to the root of your problem!

I exactly feared such a statement as "several hard coded stuff in core parts" !!

Which changes in core parts?
Why do you need them?

And you do not want to adapt them at the moment, correct?

> it just now, and I fear that by end august/early septembre, when I come with my cleaned board code,
> so much modification have been done to uboot core that 8xx cannot be back without tones of reverts.

No, if you bring in with your patchset also the core 8xx support, you have
a clean base for your patchset! And as I mentioned, yes code is in
flow, but you can use git for rebasing with current mainline and
fix merge problems ...

>> It would be very sad if we add this code now, and in a few
>> weeks/months you say: oh, we don't need this, and I don't find time
>> to care about it, let's remove it again.  And this is what's bound
>> to happen - I bet a beer or two that you have never used most of
>> this code before, nor had a look at the code.
>>
>>
>> I think it is much, much better to perform at least the file level
>> cleanup in a sngle step right at the beginning, starting with the
>> minimum set of needed files for your system.  Adding needed things
>> later is a much better guaranteee for good code than removing
>> unmaintained crap when it starts hurting.
>>
>
> Ok but please stop removing or deapply modifying additional stuff that impacts the 8xx.

Heh ... 8xx is removed. What should impact now 8xx support?

I cannot follow here your argumentation!

>> So please check your own board configuration and come up with a list
>> of needed features, and re-add only those, cleaning up file
>> hierarchy while you go.  See .sig below (non-random today).
>
> Yes but that's not something that is doable in a few hours. So be compassionate and don't jeopardise
> it.

Yes, exactly, not work for a few hours ... that has nothing to do
with being compassionate or jeopardise! Please do the necessary
changes, send a cleaner patchset and we are happy about having
mpc8xx back in a maintained state!

bye,
Heiko
>
> Thanks
> Christophe
>
>>
>> Thanks.
>>
>> Best regards,
>>
>> Wolfgang Denk
>>
>

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