From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751454AbdAOPo0 (ORCPT ); Sun, 15 Jan 2017 10:44:26 -0500 Received: from mx2.suse.de ([195.135.220.15]:47156 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751098AbdAOPoX (ORCPT ); Sun, 15 Jan 2017 10:44:23 -0500 Subject: Re: [RFT PATCH] ARM64: dts: meson-gxbb: Add reserved memory zone and usable memory range To: Heinrich Schuchardt References: <20161212101801.28491-1-narmstrong@baylibre.com> <09bb78ed-c8ec-d21f-d464-16e55c481d4e@gmx.de> <56869b90-6bee-f6ae-a7b1-884b4c0d72c0@baylibre.com> <2ac01237-a7f8-5b3b-0f97-dd49ce6623fb@gmx.de> <90d5b5a3-6dd8-aab2-8701-112a10e3364c@gmx.de> Cc: Neil Armstrong , khilman@baylibre.com, carlo@caione.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org From: =?UTF-8?Q?Andreas_F=c3=a4rber?= Organization: SUSE Linux GmbH Message-ID: <612bc7bc-4ee4-51c0-d7ac-06151854ac03@suse.de> Date: Sun, 15 Jan 2017 16:44:20 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: <90d5b5a3-6dd8-aab2-8701-112a10e3364c@gmx.de> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 23.12.2016 um 10:42 schrieb Heinrich Schuchardt: > it really makes a difference if we write > > memory@0 { > device_type = "memory"; > linux,usable-memory = <0x0 0x1000000 0x0 0x7f000000>; > }; > > or > > memory@0 { > device_type = "memory"; > reg = <0x0 0x1000000 0x0 0x7f000000>; > }; > > The second version leads to failure of the Odroid C2. > > When I looked at /sys/firmware/fdt I saw this difference: > > --- fails > +++ works > > memory@0 { > - device_type = "memory"; > reg = <0x0 0x0 0x0 0x78000000>; > + device_type = "memory"; > + linux,usable-memory = <0x0 0x1000000 0x0 0x7f000000>; > }; > > I found the following sentence in the NXP forum: > In case you want to overwrite the memory usage passed from u-boot, you > can use "linux,usable-memory". > https://community.nxp.com/thread/382284 The Odroid-C2 is in mainline U-Boot. Please submit a patch to U-Boot instead of forcing the creation of unnecessary new .dts files onto everyone due to hardcoded linux,usable-memory properties. In fact, it already reserves 0x1000000, so it seems you are merely using an older U-Boot. http://git.denx.de/?p=u-boot.git;a=blob;f=arch/arm/mach-meson/board.c;h=f159cbf849f75ab046e6f3a025bbc97c0bcfd59d;hb=HEAD#l39 I would bet that the upper limit is unrelated here. Regards, Andreas -- SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg)