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Date:      Fri, 21 Feb 2014 23:39:41 +0000
From:      =?iso-8859-1?B?V2Vp3ywgSvxyZ2Vu?= <weiss@uni-mainz.de>
To:        'Ian Lepore' <ian@FreeBSD.org>, 'Warner Losh' <wlosh@bsdimp.com>
Cc:        "'freebsd-arm@freebsd.org'" <freebsd-arm@FreeBSD.org>
Subject:   RE: About FreeBSD support one more mini-pc
Message-ID:  <dee411d1b498428a9d1a2b16c8991e03@e15be-03.zdv.Uni-Mainz.DE>
In-Reply-To: <1393010425.1145.143.camel@revolution.hippie.lan>
References:  <210081392741053@web22h.yandex.ru> <1392835264.1145.33.camel@revolution.hippie.lan> <CAB3ij4CKpp5hQWeKk5icq6dgxKX%2BtiFLho1TYKc%2BnTbufGzzFA@mail.gmail.com> <FD2977C2-7F98-4B48-81D6-87D2B81BEA78@bsdimp.com> <1392842988.1145.50.camel@revolution.hippie.lan> <CAB3ij4CHPjAspW%2BjDDOiG2bBsFZ6a5f3P9LbyDAcfxq3BYTLyw@mail.gmail.com> <1392851578.1145.55.camel@revolution.hippie.lan> <1392869044.1145.58.camel@revolution.hippie.lan> <38db362d34174f70a07c0b9ea39a54c4@e15be-03.zdv.Uni-Mainz.DE> <1392925514.1145.68.camel@revolution.hippie.lan> <C9DDC3CB-B801-42CF-8B82-D9E05A0E3AC5@bsdimp.com> <1393010425.1145.143.camel@revolution.hippie.lan>

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>=20
> The problem is that until the MMU is turned on we can't access normal
> data, bss, or even call a named function.  You can only run position-
> independant code, and that doesn't mean PLT and GOT stuff, it means you
> can only get the address of something as an offset from the current PC.
> The FDT code isn't amenable to running like that.
>=20
> However, I think the suggestion offered by Juergen is a good one:  if
> the MMU is on at entry, then our locore.S code needs to treat it as a
> mapping (set ttb) change and do the cache maintenance sequences you
> would do for that, as opposed to the sequences required to turn it on
> for the first time.  Hopefully that's all that's needed and the L2 cache
> isn't involved in the problem.  I'm going to give that a try this
> weekend.
>=20

After some reseach, I at least understand, why I can boot FreeBSD with
ubldr without any problems. I thought that the temperatures in my living
room cannot be responsible for this.

I use mkimage to generate an uImage from ubldr. And the bootm command=20
of u-boot, when booting an uImage disables and flushes all the L1 caches ..=
....=20

Juergen

Juergen Weiss      |Universitaet Mainz, Zentrum fuer Datenverarbeitung,
weiss@uni-mainz.de |55099 Mainz, Tel: +49(6131)39-26361, FAX: +49(6131)39-2=
6407




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