Date: Tue, 29 Sep 2015 10:05:14 -0600 From: Ian Lepore <ian@freebsd.org> To: Daniel Braniss <danny@cs.huji.ac.il> Cc: freebsd-arm@freebsd.org, Rick Macklem <rmacklem@uoguelph.ca> Subject: Re: netboot configuration [was: Re: NFS Root with Raspberry Pi (nfs_diskless: no interface)] Message-ID: <1443542714.1224.445.camel@freebsd.org> In-Reply-To: <AEE426FD-3BAA-4DFB-BC5D-8CB8ECB0819D@cs.huji.ac.il> References: <20150922052522.GA62140@gmail.com> <00C49FEB-E8EF-4469-85E2-0F901215CD11@cs.huji.ac.il> <20150923050414.GB43653@gmail.com> <91AAC64E-4C38-47AA-8910-48F7654A7524@cs.huji.ac.il> <20150923174445.GE43653@gmail.com> <CFAAFAE2-F0B2-431B-93C6-61D66464B7FD@cs.huji.ac.il> <1443105426.1224.272.camel@freebsd.org> <20150924163658.GC32257@gmail.com> <560438C5.3090404@selasky.org> <1443142468.1224.322.camel@freebsd.org> <FE458AF3-A9EE-46B1-89E3-1FB82E413E17@cs.huji.ac.il> <1443209159.1224.361.camel@freebsd.org> <12C96F79-2D70-408D-AD4C-F06F6B909AD3@cs.huji.ac.il> <1443276119.1224.382.camel@freebsd.org> <33EFE756-B428-4A72-B3C5-0E764FA8ACC6@cs.huji.ac.il> <1443370490.1224.392.camel@freebsd.org> <B7B0FD1E-5AA5-43DB-B494-2F5D594C43D7@cs.huji.ac.il> <1443371712.1224.398.camel@freebsd.org> <AEE426FD-3BAA-4DFB-BC5D-8CB8ECB0819D@cs.huji.ac.il>
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On Tue, 2015-09-29 at 12:24 +0300, Daniel Braniss wrote:
> > On 27 Sep 2015, at 19:35, Ian Lepore <ian@FreeBSD.org> wrote:
> >
> > On Sun, 2015-09-27 at 19:25 +0300, Daniel Braniss wrote:
> >>> On Sep 27, 2015, at 7:14 PM, Ian Lepore <ian@FreeBSD.org> wrote:
> >>>
> >>> On Sun, 2015-09-27 at 14:15 +0300, Daniel Braniss wrote:
> > [...]
> >>>> I compiled the u-boot-rpi from ports,
> >>>> the good news:
> >>>> it understands UserPreboot
> >>>> the bad news:
> >>>> the nfs boot gets stuck after a while.
> >>>>
> >>>> after much trial and error, this is what I do:
> >>>> hit a key to enter U-Boot
> >>>> then type:
> >>>> setenv loaderdev net
> >>>> boot
> >>>>
> >>>> attaching the console:
> >>>
> >>> I was also experiencing intermittant lockups while loader loads the
> >>> kernel. I just wrote it off to failing hardware (I powered my rpi on
> >>> for the first time in 6-8 months to work on this), since I've never had
> >>> a problem with netbooting before (it's the only way I've ever booted the
> >>> rpi). If it's not just my board going bad, then that's a bit of a
> >>> mystery. The only other difference here from what I've always done is
> >>> setting rootpath and other net config in u-boot instead of letting ubldr
> >>> get it from dhcp.
> >>
> >> with the stuff from crochet it works, same setup! I am sniffing the net via
> >> wireshark, and it stops at different positions in the kernel file,
> >> so the settings of rootpath and other configs are irrelevant.
> >> the transfer is being done via udp/nfs/v3 (hence added ric :-) maybe
> >> he can see something we don˙t.
> >
> > Hmmm. What stuff from crochet? The two components that are in play
> > here are u-boot itself (it contains the low-level network drivers that
> > ubldr uses -- it's effectively acting as a bios for ubldr), and ubldr
> > which contains the higher-level network code.
> >
> > In theory ubldr should be the same in both cases; nothing much has
> > changed in the loader code for months. But there are different paths
> > through the code depending on how it gets the network parms, and I could
> > easily have glitched something when I added the feature that lets you
> > set the config with u-boot env vars.
> >
> > The u-boot might be different between a crochet and ports build. They
> > both start with gonzo's u-boot 2013.10 sources, but crochet probably has
> > a slightly different set of patches it applies.
> >
> > -- Ian
> >
>
> with the old uboot it boots ok, with the newer/modified it stops at random
> places reading via udp/nfs/v3 the kernel. it loads correctly all the *.4th files,
> then starts reading the kernel, and hangs after a random time.
>
I have found that if I let u-boot get an ip address via dhcp then the
load of the kernel in ubldr never fails (I've had it reboot-looping for
24 hours now without a hang). But without letting u-boot do the dhcp
thing it hangs pretty much every time. Substituting a ping <serverip>
for the dhcp isn't enough to make it reliable.
I've stopped debugging that whole mess for now to have a quick check
whether the very latest mainline u-boot (2015.10-rc4) is able to
netboot. It sure would be nice to use something modern that has already
been debugged by others. :)
> on another issue, if I type dhcp instead of boot, it loads via TFTP filename,
> which I set to ubldr/ubldr.bin, it loads and now prompts again,
> what should the command be? I tried go 0, go 20000, in which case execs
> the old ubldr :-(
>
The old ubldr had to be launched using 'bootelf', the new ubldr.bin has
to be launched using "go ${loadaddr}". While we transition from old to
new I've been using "dhcp <dhcp parms> && bootelf || go ${loadaddr}" --
if it's ubldr the bootelf command works; if bootelf fails it fails back
to using go.
-- Ian
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