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Date:      Wed, 30 Sep 2015 10:39:23 +0300
From:      Daniel Braniss <danny@cs.huji.ac.il>
To:        Ian Lepore <ian@FreeBSD.org>
Cc:        freebsd-arm@freebsd.org
Subject:   Re: netboot configuration [was: Re: NFS Root with Raspberry Pi (nfs_diskless: no interface)]
Message-ID:  <7DBAE39E-55B2-4685-9C5E-2933B1DDFEF4@cs.huji.ac.il>
In-Reply-To: <1443542714.1224.445.camel@freebsd.org>
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> <1443542714.1224.445.camel@freebsd.org>

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> On 29 Sep 2015, at 19:05, Ian Lepore <ian@FreeBSD.org> wrote:
>=20
> 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:
>>>=20
>>> 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:
>>>>>=20
>>>>> 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.
>>>>>>=20
>>>>>> after much trial and error, this is what I do:
>>>>>> 	hit a key to enter U-Boot
>>>>>> then type:
>>>>>> 	setenv loaderdev net
>>>>>> 	boot
>>>>>>=20
>>>>>> attaching the console:
>>>>>=20
>>>>> 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.
>>>>=20
>>>> 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=C2=B4t.
>>>=20
>>> 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.
>>>=20
>>> 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.
>>>=20
>>> 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.
>>>=20
>>> -- Ian
>>>=20
>>=20
>> 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.
>>=20
>=20
> 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.
>=20
> 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. :)

there is definitely an issue with the net driver in the newer/ports =
u-boot.
	- tftpboot sometimes works :-)
	- same with nfs
=09
via dhcp:
	it should not try tftp load filename if none is supplied, i.e. =
defaulting to
	<mac-address>.img is wrong!

	i got ubldr loaded via tftp and then bootelf got it running.
	the loaded kernel complained:
		No valid device tree blob found!
	I guess some of the environmet variables got lost

my network is quiet busy, may be thats a factor?
=09
>=20
>> 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 :-(
>>=20
>=20
> 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.
>=20
> -- Ian




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