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From: Daniel Mack <zonque@gmail.com>
To: Nicolas Pitre <nico@fluxnic.net>
Cc: stigge@antcom.de, Stephen Warren <swarren@nvidia.com>,
	"devicetree-discuss@lists.ozlabs.org"
	<devicetree-discuss@lists.ozlabs.org>,
	Sven Neumann <s.neumann@raumfeld.com>,
	Mark Brown <broonie@kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: Appended DTB files for multi-machine kernels
Date: Fri, 26 Jul 2013 18:13:08 +0200	[thread overview]
Message-ID: <51F2A014.7000209@gmail.com> (raw)
In-Reply-To: <alpine.LFD.2.03.1307041322070.18597@syhkavp.arg>

On 04.07.2013 19:28, Nicolas Pitre wrote:
> On Thu, 4 Jul 2013, Daniel Mack wrote:
>> In short, devices that have been deployed in quantities come in three
>> hardware variants, which all boot with a unique machine-id. We ship
>> kernel images that have board support for all three machine types, and
>> do minor fixups to platform data of some drivers at runtime, depending
>> on the board revision number (passed in via ATAGs).
>>

> What you describe above more or less fits the definition of what I 
> called the "impedance matcher".  However it doesn't need to be part of 
> the kernel at all.  But you should make it into a separate binary.
> 
> Please have a look at the bottom of this post for a more comprehensive 
> description: http://article.gmane.org/gmane.linux.ports.arm.kernel/242929

FWIW, I gave that approach a try today for a PXA based hardware
platform, and in fact it seems to work very well. Thanks again for
sharing the idea.

In case anyone is interested, the repository is here:

  https://github.com/zonque/pxa-impedance-matcher

As the README says, it's completely specific to my use case, but maybe
anyone can use the code base to spin a different version for a different
board.


Daniel

  parent reply	other threads:[~2013-07-26 16:13 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-04 16:56 Appended DTB files for multi-machine kernels Daniel Mack
2013-07-04 17:28 ` Nicolas Pitre
     [not found]   ` <alpine.LFD.2.03.1307041322070.18597-hIgblCxmbi8OMTOF05IoTw@public.gmane.org>
2013-07-04 17:57     ` Daniel Mack
     [not found]       ` <51D5B7A1.60609-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-07-04 18:27         ` Nicolas Pitre
2013-07-26 16:13   ` Daniel Mack [this message]
2013-07-26 16:44     ` Nicolas Pitre
2013-07-29 21:23     ` [RFC PATCH 0/2] impedance-matcher generic improvements Jason Cooper
2013-07-30  7:48       ` Daniel Mack
2013-07-30 13:17         ` Jason Cooper
2013-07-30 13:37           ` Daniel Mack
2013-07-30 14:42             ` Jason Cooper
2013-07-29 21:24     ` [PATCH 1/2] add cscope Makefile target Jason Cooper
2013-07-29 21:24     ` [RFC PATCH 2/2] WIP: Get kernel and dtb addresses from command line Jason Cooper
2013-07-04 18:36 ` Appended DTB files for multi-machine kernels Dirk Behme
     [not found] ` <51D5A938.30607-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-07-04 17:11   ` Mark Brown
2013-07-04 21:34     ` Arnd Bergmann
     [not found]       ` <201307042334.37161.arnd-r2nGTMty4D4@public.gmane.org>
2013-07-04 23:02         ` Daniel Mack
2013-07-05  8:32         ` Magnus Damm
2013-07-05 18:36   ` Stephen Warren

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