[U-Boot-Users] [PATCH] Blackfin: implement go/boote wrappers

[Mike Frysinger <vapier@gentoo.org>]

On Monday 21 April 2008, Wolfgang Denk wrote:
> In message <200804210349.27495.vapier@gentoo.org> you wrote:
> > > That makes no sense to me. If you want to boot some OS, use a "boot*"
> > > commands, not "go" or the like.
> >
> > i'm not talking about operating system code, i'm talking about flat
> > binary applications that run bare metal.  something like "u-boot.bin"
> > where it's just a binary blob that gets loaded and u-boot jumps to it and
> > never returns. since "go" isnt appropriate according to you (and seeing
> > as how none of the> boot commands are appropriate), then the only next
> > step is to implement a "jump" command that is exactly like "go" except it
> > doesnt return.
>
> This makes no sense. If it is ``exactly like "go"'' it doesn't matter
> if the code returns or not (and actually this is what I'm  trying  to
> point out all the time).

the obvious implication is that i would add the cache disabling hooks to the 
jump command instead of the go command since you wont allow the hook around 
go.

> It's just that "go" shall retain the standard U-Boot environment for
> application it runs, and that the applications need to take care if
> they need to meddle with interrupts, exception handlers, etc.

U-Boot sets up no interrupts and the only exceptions that occur on the 
Blackfin are for cache handling.  disabling the caches forces a sane 
environment where applications dont have to deal with a chicken/egg of having 
to setup exception handlers before taking an exception.  we've seen it 
already with customers.
-mike
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