From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Szyprowski Subject: Re: [PATCH 0/2] Revert support for reserved memory regions defined in device tree Date: Tue, 19 Nov 2013 13:27:53 +0100 Message-ID: <528B5949.20204@samsung.com> References: <1381476448-14548-1-git-send-email-m.szyprowski@samsung.com> <20131030134702.19B57C402A0@trevor.secretlab.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20131030134702.19B57C402A0-WNowdnHR2B42iJbIjFUEsiwD8/FfD2ys@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grant Likely , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Kyungmin Park , Benjamin Herrenschmidt , Arnd Bergmann , Michal Nazarewicz , Tomasz Figa , Sylwester Nawrocki , Sascha Hauer , Laura Abbott , Rob Herring , Olof Johansson , Pawel Moll , Mark Rutland , Stephen Warren , Ian Campbell , Tomasz Figa , Kumar Gala , Nishanth Peethambaran , Marc List-Id: devicetree@vger.kernel.org Hi Grant! On 2013-10-30 14:47, Grant Likely wrote: > On Fri, 11 Oct 2013 09:27:26 +0200, Marek Szyprowski wrote: > > Hi all! > > > > Benjamin Herrenschmidt pointed a few issues in the proposed design of > > device tree bindings for contiguous memory allocator and reserved memory > > regions: > >https://lkml.org/lkml/2013/9/15/151 > >http://www.spinics.net/lists/arm-kernel/msg273548.html > > > > Some time has passed, but there is still no consensus on the bindings > > for the reserved memory and various drawback of this solution has been > > shown, so in my opinion the best I can do now is to revert them > > completely and start from scratch again later. > > Hi Marek, > > At the ARM summit last week in Edinburgh, several of us sat down and > hammered out a new proposal for handling reserved memory regions based > on the work that you started here. Below you will find a new binding > document. I started looking at implementing this, but haven't made much > progress. > > Please take a look and let me know what you think. > > Also, while I'm thinking about it, I took another look at the code and I > think the code supporting reserved regions should go directly into > drivers/of/fdt.c and drivers/of/memory.c. Also, the reserved regions > parsing should be enabled unconditionally insted of filtered by (DMA_CMA > || (HAVE_GENERIC_DMA_COHERENT && HAVE_MEMBLOCK). If the hardware > description says to reserve a region, then the kernel must always do so, > even if it doesn't actually use it for anything. Thanks for discussing this item. I'm really sorry for the late reply, but various 'more_imporant_things(tm)' have eaten me completely last weeks. The proposal look good for me. I'm not convinced that we really need the support for 'reg' property, as the fixed memory region is a special case of generic dynamic allocation specified by the size and alloc-ranges, but I assume that there have been already a long discussion about this, so I accept the common consensus. Grant: have you started working on the code, which implements such binding? If not, I will try to start do it and post the code soon for review. Best regards -- Marek Szyprowski Samsung R&D Institute Poland -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html