Date: Tue, 19 Feb 2013 10:58:56 -0700 From: Ian Lepore <ian@FreeBSD.org> To: Tim Kientzle <kientzle@FreeBSD.org> Cc: freebsd-arm@FreeBSD.org Subject: Re: RPi hangs in bootloader Message-ID: <1361296736.1164.75.camel@revolution.hippie.lan> In-Reply-To: <AAC6DACE-6E21-4311-AE1D-9BFB02263550@FreeBSD.org> References: <51227033.3070304@thieprojects.ch> <A63BA7A1-50C7-4C17-A3F2-D7ADDBCA3001@freebsd.org> <1361235912.1164.55.camel@revolution.hippie.lan> <AAC6DACE-6E21-4311-AE1D-9BFB02263550@FreeBSD.org>
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On Tue, 2013-02-19 at 09:35 -0800, Tim Kientzle wrote: > On Feb 18, 2013, at 5:05 PM, Ian Lepore wrote: > > On Mon, 2013-02-18 at 11:47 -0800, Tim Kientzle wrote: > >>> I do not understand the FDT_ERR_BADMAGIC, the page http://www.denx.de/wiki/DULG/UBootCmdFDT has a lot of those errors listed in an example session but does not explain what the message conveys? > >> > >> To help me clarify my own understanding, I wrote a brief > >> explanation of where we are with FDT handling that > >> digs into how RPi boot handles FDT today and points > >> out some of the work that still remains. > >> > > > > While you're digging around in that area of the code... is there any way > > ubldr can find out from u-boot how it was loaded? I would love it if > > ubldr could automatically set currdev=net0: if it was loaded via dhcp or > > tftp, and automatically use net0:/boot/loader.rc in that case as well. > > I believe this is possible, but it would require some C-level > work on ubldr. (And I'm not using netbooting in my current > dev environment, so I don't have a good way to test this > right now.) > > The U-Boot API does provide a way to access the U-Boot > environment variables. My work on ubldr right now is > using this to get the FDT information from U-Boot. > > If I stumble across the specific hooks needed for this, > I'll let you know. > > > The general thing I'm up to today is learning enough about ubldr to use > > it effectively, and ultimately to see if it can be used to load a > > (semi-)generic kernel plus a set of modules you configure in loader.rc. > > I've just managed to do that by hand, now to see if loader.rc will > > cooperate. > > Modulo bugs, this should all work. ubldr is just loader(8) with > U-Boot API grafted underneath instead of a PC BIOS. > So module loading and all the boot-time configuration > hooks that people are used to on x86 should Just Work. > > A couple of folks have talked about turning on FICL > in ubldr, that would open even more automation > possibilities. That's what I'm testing at this very moment. So far it seems to be working fine, except that I notice "fdt addr 0x0100" has to be in the loader.rc file, it doesn't work if it's in the loader.conf file. So I'm off to see what's up with that... -- Ian
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