From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v5 2/3] drivers: of: add initialization code for dma reserved memory
Date: Fri, 16 Aug 2013 10:06:46 -0600 [thread overview]
Message-ID: <520E4E16.3040408@wwwdotorg.org> (raw)
In-Reply-To: <20130816052520.GA7035@quad.lixom.net>
On 08/15/2013 11:25 PM, Olof Johansson wrote:
> On Tue, Aug 13, 2013 at 02:08:44PM -0600, Stephen Warren wrote:
>> On 08/09/2013 05:51 AM, Marek Szyprowski wrote:
>>> Add device tree support for contiguous and reserved memory regions
>>> defined in device tree. Initialization is done in 2 steps. First, the
>>> memory is reserved, what happens very early when only flattened device
>>> tree is available. Then on device initialization the corresponding cma
>>> and reserved regions are assigned to each device structure.
>>
>> Hmmm. This seems an awful lot like putting SW configuration/policy
>> information into DT rather than HW description. This feels like a
>> slippery slope... Isn't this kind of thing better handled by a kernel
>> command-line option to set up the CMA size?
>
> Sorry, you were not part of the in-person discussion since it happened
> at Linaro Connect in Dublin. The concern is that we really need a way
> to describe some of these _system_ properties. They're not necessarily
> hardware properties, but they are well-known and likely properties of
> the system that is running.
OK, that seems reasonable enough. It's just the first I heard of this.
I rather suspect that similar arguments will be applied to a bunch of
other data people want to put into DT. I guess we'll just have to wait
and see what gets proposed, and what really is "system data" rather than
policy:-)
next prev parent reply other threads:[~2013-08-16 16:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-09 11:51 [PATCH v5 0/3] Device Tree support for CMA (Contiguous Memory Allocator) Marek Szyprowski
2013-08-09 11:51 ` [PATCH v5 1/3] drivers: dma-contiguous: clean source code and prepare for device tree Marek Szyprowski
2013-08-09 11:51 ` [PATCH v5 2/3] drivers: of: add initialization code for dma reserved memory Marek Szyprowski
2013-08-10 17:33 ` Rob Herring
2013-08-12 8:34 ` Marek Szyprowski
2013-08-13 13:00 ` Rob Herring
2013-08-19 14:47 ` Marek Szyprowski
2013-08-19 19:36 ` Rob Herring
2013-08-13 20:08 ` Stephen Warren
2013-08-16 5:25 ` Olof Johansson
2013-08-16 16:06 ` Stephen Warren [this message]
2013-08-16 5:32 ` Olof Johansson
2013-08-09 11:51 ` [PATCH v5 3/3] ARM: init: add support for reserved memory defined by device tree Marek Szyprowski
2013-08-09 13:19 ` [PATCH v5 0/3] Device Tree support for CMA (Contiguous Memory Allocator) Tomasz Figa
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