From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] dma: of-dma: return error when 'dma-cells' not found
Date: Tue, 05 Mar 2013 11:15:41 +0100 [thread overview]
Message-ID: <1859273.NY466Orvuh@wuerfel> (raw)
In-Reply-To: <5135BE58.4040105@gmail.com>
On Tuesday 05 March 2013 03:43:52 Rob Herring wrote:
> On 03/05/2013 03:25 AM, Padmavathi Venna wrote:
> > This patch returns error when 'dma-cells' property not found
> > in the corresponding device node. With out this change there
> > is a crash in the generic dma incompatible platforms.
> >
> > Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
>
> NAK.
>
> #dma-cells should be optional. It is not needed for platforms supporting
> memory to memory transfers only and should therefore be optional. You
> cannot assume the dtb can be updated and kernel changes need to work
> with old dtbs. I've submitted patches to address this and fix the crash:
>
> https://lists.ozlabs.org/pipermail/devicetree-discuss/2013-February/028769.html
Why would you call of_dma_controller_register() for a dma
engine that does not support slave channels, when that is the
only purpose of that interface?
Note that the binding defines #dma-cells as required, and it
does not make any sense otherwise.
Arnd
next prev parent reply other threads:[~2013-03-05 10:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-05 9:25 [PATCH] dma: of-dma: return error when 'dma-cells' not found Padmavathi Venna
2013-03-05 9:25 ` [PATCH V2] DMA: PL330: Add check if device tree compatible Padmavathi Venna
2013-03-13 5:36 ` Padma Venkat
2013-03-21 9:39 ` Vinod Koul
2013-04-01 13:13 ` Rob Herring
2013-04-01 18:21 ` Vinod Koul
2013-04-02 2:58 ` Padma Venkat
2013-03-05 9:43 ` [PATCH] dma: of-dma: return error when 'dma-cells' not found Rob Herring
2013-03-05 10:04 ` Padma Venkat
2013-03-05 10:15 ` Arnd Bergmann [this message]
2013-03-05 14:56 ` Rob Herring
2013-03-05 19:48 ` Arnd Bergmann
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