[PATCH 0/3] arm: mvebu: Espressobin: Set default env values at runtime

[Stefan Roese]

Hi Pali,
Hi Andre,

On 12.01.21 10:24, Pali Rohár wrote:
> Hello!
> 
> On Tuesday 12 January 2021 09:18:44 Andre Heider wrote:
>> Hi Pali,
>>
>> On 11/01/2021 11:51, Pali Rohár wrote:
>>> Hello Stefan and Andre!
>>>
>>> Could you please look at this patch series and tell me what do you think
>>> about it? If it is fine or needs to take different approach?
>>
>> I like the idea very much, and I bet there're quite some boards which could
>> make good use of "immutable envvars".
>>
>> The obvious review point is the filler thing and its dependency on
>> DEFAULT_ENV_IS_RW, which probably won't win a beauty contest :) Maybe a
>> nicer integration would help in getting it merged?
>>
>> I don't think it would take too much effort, first thing that comes to mind:
>> - board provides list of immutable vars
>> - env_set_default() backs up these vars
>> - env_set_default() imports default_environment
>> - env_set_default() imports backup on top
>>
>> The last step should be easy, see env_set_default_vars().
> 
> This could probably work for $ethNaddr variables.
> 
> But there is still an issue how to handle $fdtfile. There is basically
> default value for this variable, but value itself cannot be determined
> at compile time, only at runtime. And for it variable flags do not help,
> we just need an mechanism how to set default variable values not only at
> compile time but also runtime.
> 
> That is why I chosen for now solution with modifying
> default_environment[] array as it solve issue for both $fdtfile and
> $ethNaddr variables.

So what is the outcome of this discussion? Andre, do you see any
hindering points in this patch series, apart from it not winning a
"beauty contest"? ;)

I tend to pull it in shortly, if nobody objects.

Thanks,
Stefan

>> Maybe the first step can be solved with ENV_FLAGS_VAR, a new immutable flag,
>> and boards just making use of CONFIG_ENV_FLAGS_LIST_DEFAULT to declare
>> those. But I fail to find an example in-tree.
>>
>> Thanks,
>> Andre
>>
>>>
>>> On Wednesday 23 December 2020 12:21:27 Pali Rohár wrote:
>>>> This patch series set default env values of $fdtfile and $ethNaddr for
>>>> Espressobin board at runtime.
>>>>
>>>> It fixes two main issues on Espressobin board that 'env default -a'
>>>> completely erases permanent board MAC addresses and also erase $fdtfile
>>>> variable which is needed for booting Linux kernel via distro boot.
>>>>
>>>> Lot of people were complaining about erasing permanent MAC addresses by
>>>> U-boot on this board and due to this issue some linux distributions
>>>> started using static hardcoded MAC addresses for all Espressobin boards
>>>> to workaround this issue. Apparently erase of MAC addresses or usage of
>>>> static hardcoded value caused more issues on network (e.g. inability to
>>>> connect two of these boards to the same network).
>>>>
>>>> Pali Rohár (3):
>>>>     env: Allow to set default_environment[] from board code via compile
>>>>       option DEFAULT_ENV_IS_RW
>>>>     arm: mvebu: Espressobin: Set default value for $fdtfile env variable
>>>>     arm: mvebu: Espressobin: Set default value for $ethNaddr env variable
>>>>
>>>>    board/Marvell/mvebu_armada-37xx/board.c | 41 ++++++++++++++++++++-----
>>>>    include/configs/mvebu_armada-37xx.h     | 17 +++++++++-
>>>>    include/env_default.h                   |  2 ++
>>>>    include/env_internal.h                  |  4 +++
>>>>    4 files changed, 56 insertions(+), 8 deletions(-)
>>>>
>>>> -- 
>>>> 2.20.1
>>>>
>>


Viele Grüße,
Stefan

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: sr at denx.de