From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: [PATCH 0/2] Device Tree support for CMA (Contiguous Memory Allocator) Date: Thu, 14 Feb 2013 22:30:13 +0100 Message-ID: <20130214213013.GG1906@pengutronix.de> References: <1360845928-8107-1-git-send-email-m.szyprowski@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1360845928-8107-1-git-send-email-m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Marek Szyprowski Cc: linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org, Kyungmin Park , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Michal Nazarewicz , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org Hi Marek, On Thu, Feb 14, 2013 at 01:45:26PM +0100, Marek Szyprowski wrote: > Hello, > > Here is my initial proposal for device tree integration for Contiguous > Memory Allocator. The code is quite straightforward, however I expect > that the memory bindings require some discussion. > > The proposed bindings allows to define contiguous memory regions of > specified base address and size. Then, the defined regions can be > assigned to the given device(s) by adding a property with a phanle to > the defined contiguous memory region. From the device tree perspective > that's all. Once the bindings are added, all the memory allocations from > dma-mapping subsystem will be served from the defined contiguous memory > regions. > I think CMA regions should not be described in the devicetre at all. The devicetree is about hardware description and it should be OS agnostic, but CMA is only a Linux specific implementation detail. It's not even specific to a particular board, it's specific to a particular usecase of a board. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | From mboxrd@z Thu Jan 1 00:00:00 1970 From: s.hauer@pengutronix.de (Sascha Hauer) Date: Thu, 14 Feb 2013 22:30:13 +0100 Subject: [PATCH 0/2] Device Tree support for CMA (Contiguous Memory Allocator) In-Reply-To: <1360845928-8107-1-git-send-email-m.szyprowski@samsung.com> References: <1360845928-8107-1-git-send-email-m.szyprowski@samsung.com> Message-ID: <20130214213013.GG1906@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Marek, On Thu, Feb 14, 2013 at 01:45:26PM +0100, Marek Szyprowski wrote: > Hello, > > Here is my initial proposal for device tree integration for Contiguous > Memory Allocator. The code is quite straightforward, however I expect > that the memory bindings require some discussion. > > The proposed bindings allows to define contiguous memory regions of > specified base address and size. Then, the defined regions can be > assigned to the given device(s) by adding a property with a phanle to > the defined contiguous memory region. From the device tree perspective > that's all. Once the bindings are added, all the memory allocations from > dma-mapping subsystem will be served from the defined contiguous memory > regions. > I think CMA regions should not be described in the devicetre at all. The devicetree is about hardware description and it should be OS agnostic, but CMA is only a Linux specific implementation detail. It's not even specific to a particular board, it's specific to a particular usecase of a board. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |