From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH v3 2/2] drivers: dma-contiguous: add initialization from device tree Date: Mon, 16 Sep 2013 12:58:26 +1000 Message-ID: <1379300306.4098.79.camel@pasglop> References: <1372254009-25307-1-git-send-email-m.szyprowski@samsung.com> <1372254009-25307-3-git-send-email-m.szyprowski@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Grant Likely Cc: devicetree@vger.kernel.org, Sascha Hauer , Kyungmin Park , Michal Nazarewicz , linaro-mm-sig@lists.linaro.org, Marc , Nishanth Peethambaran , Sylwester Nawrocki , "linux-arm-kernel@lists.infradead.org" , Marek Szyprowski List-Id: devicetree@vger.kernel.org [resent to the right list this time around] On Thu, 2013-07-11 at 15:56 +0100, Grant Likely wrote: > > +contiguous-memory { > > + > > + (name): region@(base-address) { > > + reg = <(baseaddr) (size)>; > > + (linux,default-contiguous-region); > > + device = <&device_0 &device_1 ...> > > + }; > > +}; > > Okay, I've gone and read all of the backlog on the 3 versions of the > patch series, and I think I understand the issues. I actually think it > was better off to have the regions specified as children of the memory > node. I understand the argument about how would firmware know what > size the kernel wants and that it would be better to have a kernel > parameter to override the default. However, it is also reasonable for > the kernel to be provided with a default amount of CMA based on the > usage profile of the device. In that regard it is absolutely > appropriate to put the CMA region data into the memory node. I don't > think /chosen is the right place for that. Picking up on that old thread after the rant I just posted ... Grant, your proposal is all wrong. First we already had a proposal for reserved memory, which due to the complete lack of comment, we actually merged support for in powerpc in 3.11, second, do NOT make that a child of "memory". See the email I just posted today for more details about the breakage in that proposal. I'm advocating a revert at this stage. Ben.