[U-Boot] [PATCH] bin_dep.sh Support

Mike Frysinger vapier at gentoo.org
Tue Apr 7 01:01:19 CEST 2009


On Monday 06 April 2009 15:49:43 Wolfgang Denk wrote:
> In message Scott Wood wrote:
> > > There are tons of standards for image formats, and even more commonly
> > > used formats I would not dare to call standard; but this processor
> > > has to invent yet another one?
> >
> > The same could be said about u-boot requiring its own image format (ELF
> > and raw binary images can't be passed a device tree or bd_t, AFAICT).
>
> When the U-Boot (or rather PPCBoot at that time) development was
> starte, there was a very important reason for not using ELF: wasting
> a full 64 kB for the standard ELF file header was unthinkable on most
> embedded devices of that time.
>
> Now, on fat systems with ample resource on one side, and on the other
> side with the infrastructure more or less in place to compose a bootm
> command from small,  separate  building  blocks,  it  should  be  not
> difficult to add such a feature, too.
>
> On the other hand, ELF images are missing a few key points  available
> in  U-Boot  images  so  I would not recommend using plain ELF for any
> system where reliability or just ease of use are important (which was
> the other part of the rationale that led to that format).

which are the same reasons processors do not implement support for ELF as a 
booting source ...

lets say i was to design a brand new part today with an on-chip rom that 
supports booting from a variety of sources (UART, SPI/I2C/NAND flashes, 
directly addressable NOR flashes, as a slave device to SPI/I2C, etc...), what 
format would you recommend that could satisfy all of these requirements ?  i'm 
not aware of any which is why the Blackfin processor has its own stripped down 
LDR format.
-mike


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