[U-Boot] zImage on ARM

[Wolfgang Denk]

Dear Scott Wood,

In message <20100909112816.7bd37645 at schlenkerla.am.freescale.net> you wrote:
>
> Then why does u-boot only support certain calling conventions with
> certain image formats?

The "bootm" command supports only images it understands.

> So in other words, for booting an OS, U-Boot insists on particular
> image formats.

No, it does not. You can provide the OS in a  U-Boot specific
standard way (FIT or legacy image format), you can provide it in a
system independent format (ELF), or you can provide it in a "simple
binary" format (to be used with "go").

> > The go command takes arguments, which get passed to the started
> > application in the standard C calling convention. It is up to the
> > image to interpret these, then.
> 
> It passes *text* arguments supplied by the command line, in argc/argv
> format.  Which seems like it's not intended to be an arbitrary image
> loading command, but rather a facility to execute things that look and
> feel like shell commands.

It's the standard C calling convention, i. e. pretty common standard.

> Yes.  "simple" refers to the image format, not the calling convention.

As I explained before: feel free to craft your own specific boot
command from the building blocks provided.

There is a standard way of doing this; if you don't want to use it
it's fine with me. Define a "bootz" command or whatever you like.

Don't expect me to scratch your itches, though. In all the past 10
years when I've been working with PPCBoot and U-Boot I never felt the
need to boot a zImage.

Best regards,

Wolfgang Denk

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