[ECOS] ROMRAM startup in arm arch

Gary D. Thomas gary.thomas@mind.be
Fri Jan 31 18:07:00 GMT 2003

On Fri, 2003-01-31 at 10:53, Mark Salter wrote:
> >>>>> Jonathan Larmour writes:
> > Are there any ARM platforms with ROMRAM startup that _don't_ copy it in 
> > the platform HAL?
> > The AT91 seems to only relocate 0x10000 bytes (64K) no matter what which 
> > looks quite odd indeed.
> > The aaed2000, excalibur, ebsa285, as well as edb7xxx and integrator as we 
> > know all seem to copy all ROM.
> > So any reasons for me not to tweak vectors.S to relocate from ROM to RAM 
> > only for ROM startup? And fix the at91 to be consistent with the other 
> > platforms?
> Is there any reason to copy all ROM? Ideally, just copy that part of ROM
> which actually contains something useful.

The code currently (except for the AT91 does so - it just copies
TEXT + RODATA + DATA from ROM/FLASH to RAM.  The problem is that
the initialized DATA stuff is lumped with the RODATA (by the
linking process - at least with the way we've traditionally
laid out the labels) and so it gets copied by the ROM->RAM
relocation and then again by the ROM "initialize DATA from
RODATA" in vectors.S).  It's this "extra" latter copy which
is under consideration.

|       Mind: Embedded Linux and eCos Development        |
| Gary Thomas              email:  gary.thomas@mind.be   |
| Mind ( http://mind.be )  tel:    +1 (970) 229-1963     |
| gpg: http://www.chez-thomas.org/gary/gpg_key.asc       |

Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss

More information about the Ecos-discuss mailing list