[U-Boot] [PATCH] arm: Add option to disable code relocation

[Graeme Russ]

Hi Mike,

On Tue, Feb 7, 2012 at 6:27 AM, Mike Frysinger <vapier at gentoo.org> wrote:
> On Monday 06 February 2012 09:49:27 Tom Rini wrote:
>> On Mon, Feb 6, 2012 at 1:43 AM, Graeme Russ wrote:
>> > On 02/06/2012 06:51 PM, Wolfgang Denk wrote:
>> >> Graeme Russ wrote:
>> >>> I think the immediate focus should be on centralising the init sequence
>> >>> processing into /common/init.c and then bringing the new'initcall'
>> >>> architecture online
>> >>
>> >> Agreed.
>> >>
>> >>> Once these have been done, any board can just specific:
>> >>>
>> >>> SKIP_INIT(RELOC)
>> >>
>> >> I will probably object to his, too - for the same reasons.
>> >
>> > Considering this is a 'free' artefact of how the init sequence functions,
>> > and that it is board specific and totally non-invasive for anyone else
>> > (i.e. no ugly ifdef's anywhere else in the code) I'm surprised you would
>> > object...
>>
>> To pick up Wolfgang's argument, but why do we want to skip relocation?
>>  You can debug through it, it's documented (official wiki has GDB,
>> over in TI-land, the wiki page for CCS has the bits for doing it in
>> that Eclipse-based env, other debuggers I'm sure have a similar "now
>> add symbols at this offset from link" option) and the end result makes
>> it very easy for end-users to break their world (default kernel load
>> addrs being where U-Boot would be).
>
> if you have a static platform which never changes, isn't the relocation a
> waste of time ?  i can understand wanting relocation by default for platforms
> where memory sizes are unknown, but it's not uncommon for people to have fixed
> hardware when they deploy.

Also, if SPL can determine total SDRAM, copy U-Boot to the final location
and perform the relocations, there is no need for relocation to be done by
U-Boot. As I understand it, SPL loads U-Boot into a fixed address and then
U-Boot copies itself to top-of-RAM. We can save one copy

Regards,

Graeme