Code review request: boards on AT91
stas at FreeBSD.org
Tue Nov 25 11:21:34 PST 2008
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On Tue, 25 Nov 2008 12:05:23 -0700 (MST)
"M. Warner Losh" <imp at bsdimp.com> mentioned:
> In message: <20081125220040.c8996e0b.stas at FreeBSD.org>
> Stanislav Sedov <stas at FreeBSD.org> writes:
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> : On Tue, 25 Nov 2008 11:36:47 -0700 (MST)
> : "M. Warner Losh" <imp at bsdimp.com> mentioned:
> : > :
> : > : I think we could pass the board type via a special kenv variable
> : > : for now. I think it will work fine and applicable to all supported
> : > : architectures. We could probably reuse board type constants that Linux
> : > : kernel uses.
> : >
> : > Right now that's passed in from uboot and other loaders in I think r3,
> : > but I'd have to go look at some other code to be sure.
> : >
> : Well, I don't think we want to follow The Linux kernel argument passing
> : paradigm... But using a simple kenv variable would be just fine.
> : We have a patch ready for kenv/hints support in u-boot and in
> : our arm port, and our loader could be used on arm with Rafal's
> : u-boot API.
> You are assuming that /boot/loader is always used. In the cases where
> it isn't, we need that value from r3. when it is, a kenv could be
> used. This switching likely also needs to be configurable more easily
> than it is now.
We can't support all bootloaders on the Earth, and I think it's the job
of bootloader to support the kernel it booting. Linux also mandates it's
own argument passing mechanism method should be used, and doesn't support
anything else. As we're using kenv for this task, and no well-accepted
generic multiplatform method yet available, I think we could stick with
kenv for now. I don't see the reason to complicate our kernel code more
to support several argument passing methods.
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