[U-Boot] [PATCH V3 3/8] arm: Add savebp implementation for arm

[Andreas Bießmann]

Dear Simon,

Am 26.08.2011 12:10, schrieb Simon Schwarz:
> Dear Andreas,
> 

<snip>

>> BTW while reading this patch I got another idea to solve problem 'how
>> get we saved the boot information to<storage>'.
>> The required information regardless of whether it is ATAGS or FDT is
>> only a blob at some place in ram after the 'bootm x' commands used in
>> 'Add savebp command'. Saving a blob from location X with size Y to
>> location Z is easy and already implemented.
>>
>> So the only required thing is to get the 'blob' prepared in RAM. In my
>> opinion this could be a subcommand of bootm instead of a new command.
>>
>> How about:
>>
>> ---8<---
>> # bootm savebp
>> ...done boot information is @0x80000100 with size 0x100
>> # nandecc hw
>> # nand erase ...
>> # nand write 80000100 ...
>> --->8---
> 
> This was actually my first implementation (although not with a switch):
> http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/102669
> 
> It was criticised because saving the parameter images is not the
> responsibility of bootm - which is true. Although adding a switch would
> be a cleaner solution than my first implementation - would that be
> acceptable?
> 
> How about implementing it as bootm subcommand?

Another question, how often will one change the boot information for SPL
booting?
I guess most people will use the normal u-boot to test different
configurations and start directly into the OS. When one has some
satisfying configuration he will store this for SPL boot into flash
regardless whether it is a separate command or a list of commands.

The current solution (having savebp command utilize do_bootm()) couples
these two commands in a way which may lead to problems in future (but I
don't know what others think about ... Wolfgang?).

I vote for a well documented guide or an example script to gather the
boot information and store it for SPL booting (at least for this patch
set). I know your bachelor thesis filing date is end of September and I
would appreciate to have this functionality in before. The rest of this
series seems quite good to me. Except for some minor changes to the
arm-bootm prep command ... but read my answer to that patch.

best regards

Andreas Bießmann