[U-Boot] environment access before relocation does not work on (some) arm

[U-Boot] environment access before relocation does not work on (some) arm

[Matthias Fuchs]

Hi,

I just noticed that using getenv (and friends)
does not work on ARM (namely i.MX28) from board_init_f()
after running through the init_sequence.

So getenv_ulong() always returns the given default.
So the baudrate on affected boards is always set by CONFIG_BAUDRATE
and cannot be adjusted by the baudrate env variable and so on.
Environment access before relocation is required for some functions:
pram, fdtcontroladdr, baudrate, ...

Env access does not work before env_relocate() in board_init_r().

Didn't this behave different sometimes before? Even after the big
env rework?

Matthias

[U-Boot] environment access before relocation does not work on (some) arm

[Wolfgang Denk]

Dear Matthias Fuchs,

In message <4FED7877.2020505@esd.eu> you wrote:
> 
> I just noticed that using getenv (and friends)
> does not work on ARM (namely i.MX28) from board_init_f()
> after running through the init_sequence.

This is normal, and documented.  Before relocation, you must not use
getenv().  

> Env access does not work before env_relocate() in board_init_r().

It does, but you have to play by the rules, i. e. use getenv_f()
instead.

> Didn't this behave different sometimes before? Even after the big
> env rework?

No. The use of getenv() before relocation has never been supported.
It may have worked (by pure chance) on some systems, but that's all.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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[U-Boot] environment access before relocation does not work on (some) arm

[Matthias Fuchs]

Hi,

On 29.06.2012 13:26, Wolfgang Denk wrote:
> Dear Matthias Fuchs,
> 
> In message <4FED7877.2020505@esd.eu> you wrote:
>>
>> I just noticed that using getenv (and friends)
>> does not work on ARM (namely i.MX28) from board_init_f()
>> after running through the init_sequence.
> 
> This is normal, and documented.  Before relocation, you must not use
> getenv().  
Yes, I am aware of this. I even think that the getenv() implementation
falls back to getenv_f() before relocation.
> 
>> Env access does not work before env_relocate() in board_init_r().
> 
> It does, but you have to play by the rules, i. e. use getenv_f()
> instead.
Yes, I did not care about where my env comes from :-) So env_sf.c does
not support an early env at all. Running on an i.MX28 with env in a SPI
flash I probably need SPI support in my SPL and an improved env_sf.c.

... and all this to get CONFIG_PRAM working in arch/arm/lib/board.c.
So I will stuck at using a constant pram value for the moment. This works.
> 
>> Didn't this behave different sometimes before? Even after the big
>> env rework?
> 
> No. The use of getenv() before relocation has never been supported.
> It may have worked (by pure chance) on some systems, but that's all.
Of course. My question was not very precise.

Matthias

> 
> Best regards,
> 
> Wolfgang Denk
> 

[U-Boot] environment access before relocation does not work on (some) arm

[Wolfgang Denk]

Dear Matthias Fuchs,

In message <4FF306FC.9040305@esd.eu> you wrote:
> 
> > This is normal, and documented.  Before relocation, you must not use
> > getenv().  
> Yes, I am aware of this. I even think that the getenv() implementation
> falls back to getenv_f() before relocation.

This is not guaranteed to work.

> Yes, I did not care about where my env comes from :-) So env_sf.c does
> not support an early env at all. Running on an i.MX28 with env in a SPI
> flash I probably need SPI support in my SPL and an improved env_sf.c.

This is a bigger topic.  We all wait anxiously for Mareks group to
implement a clean device driver model, so we can clean up and unify
all this code.  I am aware that it needs it.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"Remember, Information is not knowledge;  Knowledge  is  not  Wisdom;
Wisdom is not truth; Truth is not beauty; Beauty is not love; Love is
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