[U-Boot-Users] RFC: new bootm syntax

Wolfgang Denk wd at denx.de
Tue Jan 8 15:52:05 CET 2008


Dear Bartek,

in message <47837703.6030206 at semihalf.com> you wrote:
>
> > What do you mean by "+load_addr" ? Looks bogus to me.
> 
> Let's consider the following example:
> 
> bootm 200000 10000
> 
> If the image at address 200000 is of type IH_TYPE_STANDALONE, then the
> current code will use 10000 as the load address, no matter what is
> specified in header->ih_load. Then the control will be passed to
> header->ih_ep (entry point).

I see. Guess someone should update / extend the documentation...

Any volunteers?

> > This makes no sense to me. The whole purpose of the new image  format
> >  is  to  make  the image self-describing; I don't see how 8, 9, or 10
> >  would be different.
> 
> They are different syntactically:
> 
> 8. bootm 400000
> 9. bootm 400000:kernel at 1
> 10. bootm 400000#cfg at 1
> 
> But this will become clearer when A-F notation is dropped.

Yes, please.

> > Note: the officially documented method to start a standalone program 
> > is "go".
> 
> Well, there's quite a bit of support for standalone applications outside
> of the "go" command. For example current image format has provisions for

I know, but as mentioned above, this is not really documented (which
means a deficiency on the decoumentation).

> it; from include/image.h:
> dress of new uImage D new
>  >> uImage sub-image specification E new uImag
> /*
> * Image Types
> *
> * "Standalone Programs" are directly runnable in the environment
> * provided by U-Boot; it is expected that (if they behave
> * well) you can continue to work in U-Boot after return from
> * the Standalone Program.

I guess there was a problem with what you intended to quote?

> Also, do_bootm (as indicated already) knows how to handle and run
> standalone applications.

Yes, I remember.

> The question now is: what to do with support for standalone apps that is
> outside of "go"? Should the code be changed to match the documentation?

...or vice versa.

> I'll be more than happy to remove standalone apps support from both
> bootm and old/new image format, as it does not logically belong there,
> and unnecessarily complicates the code. What is your opinion on such a
> change?

If I remember correctly, the main reason to add it there was to  take
a  shortcut  instead of implementing a "gunzip" command, or something
like that.

IMO it could be removed there. I agree that it doesn;t logically
belong there.

What do others think?

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
When a woman marries again it is because she detested her first  hus-
band.  When  a  man  marries again, it is because he adored his first
wife.                                                  -- Oscar Wilde




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