From mboxrd@z Thu Jan  1 00:00:00 1970
From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni)
Date: Wed, 22 May 2013 18:57:57 +0200
Subject: [PATCH 0/9] Switch internal registers address to 0xF1 on Armada
 370/XP
In-Reply-To: <20130522164936.GE31290@titan.lakedaemon.net>
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 <20130522163557.GC27348@1wt.eu> <20130522184250.1d5f2f10@skate>
 <20130522164936.GE31290@titan.lakedaemon.net>
Message-ID: <20130522185757.60091a66@skate>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Dear Jason Cooper,

On Wed, 22 May 2013 12:49:36 -0400, Jason Cooper wrote:

> > As far as I know, a DT-capable bootloader doesn't pass any ATAG. The
> > ARM register that was used to pass the pointer to the ATAGS is now used
> > to pass the pointer to the DTB in memory.
> 
> So we could look for the ATAG magic or the dtb magic at that address,
> then we know if we have an old or new bootloader...

No, because you can use an old bootloader, and still do some old-style
appended-DTB booting, in which case you have a new bootloader
(registers mapped at 0xf1), but you see the ATAG magic, which will make
you think you booted from an old bootloader (registers mapped at 0xd0).

For example, I'm currently booting alternatively with an old and a new
bootloader (to test that things work properly), and in both cases I'm
booting old style, DTB-appended, with ATAGs.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com