From: Matt Porter <mporter@kernel.crashing.org>
To: Ralph Siemsen <rsiemsen@rossvideo.com>
Cc: linuxppc-dev@lists.linuxppc.org
Subject: Re: early UART mapping in head_44x.S
Date: Thu, 22 Jul 2004 16:55:36 -0700 [thread overview]
Message-ID: <20040722165536.B20296@home.com> (raw)
In-Reply-To: <40F452D6.9020806@rossvideo.com>; from rsiemsen@rossvideo.com on Tue, Jul 13, 2004 at 05:23:34PM -0400
On Tue, Jul 13, 2004 at 05:23:34PM -0400, Ralph Siemsen wrote:
>
> I've been trying to boot a vanilla 2.6.7 kernel on a board similar to
> Ocotea (the board boots 2.4.x okay). I wasn't getting any serial
> output, despite setting CONFIG_SERIAL_TEXT_DEBUG and doing early
> registration of a console (as per David Woodhouse's posts on this list).
That's a separate issue. I need to go through and early register
the console on 4xx when I get a moment.
> After much tracing and a lucky suggestion on IRC, I seem to have
> stumbled on the cause, although I don't fully understand what is going
> on. In arch/ppc/kernel/head_44x.S (from 2.6.7 mainline) there is a
> block of code that sets up the "early UART mapping". It does three
> tlbwe instructions, and then repeats the same a second time but in
> "Translation state 1". This second set seems to cause my problems.
> When I comment out the 5 instructions before the isync, I magically
> start getting printk outputs.
Yeah, I fat-fingered the last patch to head_44x.S and left the
duplicate code fragment there. There's a patch submitted to fix
this in mainline.
-Matt
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2004-07-22 23:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-13 21:23 early UART mapping in head_44x.S Ralph Siemsen
2004-07-13 21:51 ` Ralph Siemsen
2004-07-13 22:28 ` James Perkins
2004-07-13 22:48 ` Ralph Siemsen
2004-07-22 23:55 ` Matt Porter [this message]
-- strict thread matches above, loose matches on Subject: below --
2004-08-02 12:30 Daren Hayward
2004-08-02 13:57 ` Matt Porter
2004-08-03 17:58 ` Ralph Siemsen
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