From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: Build failure with DMA_OMAP=m and a caller built-in
Date: Tue, 8 Jan 2013 22:56:30 +0000 [thread overview]
Message-ID: <201301082256.30639.arnd@arndb.de> (raw)
In-Reply-To: <20130107203834.GB2637@n2100.arm.linux.org.uk>
On Monday 07 January 2013, Russell King - ARM Linux wrote:
> The problem we have is that the way peripheral devices are connected to
> their DMA engines can involve additional complexity, which if not handled
> correctly results in some platforms being crippled by the API.
>
> I think Vinod was working on something, however I've not heard anything on
> that for a while now.
>
> How we avoid this problem outside of OMAP is that the DMA filter function
> gets passed from platform code, and we only ever allow the DMA engine
> driver to be configured into the kernel (iow, non-modular). This means
> that the DMA users never directly reference the DMA engine driver itself.
> However, as OMAP headed down the DT path, many drivers no longer make use
> of platform data, which makes that approach impractical.
Hmm, it seems the generic DT binding for dmaengine missed the merge window
again, Vinod's pull request came a bit too late for this[1].
Anyway, once the binding and code from Jon Hunter is there, and the omap-dma
converted over to use it, the problem should be gone, unless you see any
other issues with it. Drivers no longer need to reference a filter function
directly, since the dma channel can get described completely in the DT.
Arnd
[1] http://lkml.org/lkml/2012/12/21/466
prev parent reply other threads:[~2013-01-08 22:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1357449969.4324.25.camel@deadeye.wl.decadent.org.uk>
2013-01-07 20:21 ` Build failure with DMA_OMAP=m and a caller built-in Tony Lindgren
2013-01-07 20:36 ` Tony Lindgren
2013-01-07 20:38 ` Russell King - ARM Linux
2013-01-08 9:02 ` Vinod Koul
2013-01-08 22:56 ` Arnd Bergmann [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=201301082256.30639.arnd@arndb.de \
--to=arnd@arndb$(echo .)de \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox