From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751599AbdAPKj6 (ORCPT ); Mon, 16 Jan 2017 05:39:58 -0500 Received: from mail-wm0-f48.google.com ([74.125.82.48]:34145 "EHLO mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751386AbdAPKj4 (ORCPT ); Mon, 16 Jan 2017 05:39:56 -0500 Subject: Re: [PATCH v4] ARM64: dts: meson-gx: Add reserved memory zone and usable memory range To: =?UTF-8?Q?Andreas_F=c3=a4rber?= , Kevin Hilman References: <1484129414-23325-1-git-send-email-narmstrong@baylibre.com> Cc: devicetree@vger.kernel.org, xypron.glpk@gmx.de, linux-kernel@vger.kernel.org, carlo@caione.org, linux-amlogic@lists.infradead.org, linux-arm-kernel@lists.infradead.org From: Neil Armstrong Organization: Baylibre Message-ID: <7fcb8d94-840a-de2c-f43b-9123ccc65514@baylibre.com> Date: Mon, 16 Jan 2017 11:39:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: 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 On 01/15/2017 03:43 PM, Andreas Färber wrote: > Am 13.01.2017 um 21:03 schrieb Kevin Hilman: >> Neil Armstrong writes: >> >>> The Amlogic Meson GXBB/GXL/GXM secure monitor uses part of the memory space, >>> this patch adds this reserved zone and redefines the usable memory range. >>> >>> The memory node is also moved from the dtsi files into the proper dts files >>> to handle variants memory sizes. >>> >>> This patch also fixes the memory sizes for the following platforms : >>> - gxl-s905x-p212 : 1GiB instead of 2GiB, a proper 2GiB dts should be pushed >>> - gxm-s912-q201 : 1GiB instead of 2GiB, a proper 2GiB dts should be pushed >>> - gxl-s905d-p231 : 1GiB instead of 2GiB, a proper 2GiB dts should be pushed >>> - gxl-nexbox-a95x : 1GiB instead of 2GiB, a proper 2GiB dts should be pushed >>> >>> Signed-off-by: Neil Armstrong >> >> Queued for v4.10-rc. > > What is the motivation for this change? I have a local U-Boot patch to > detect the amount of memory available as done downstream, but U-Boot > only updates the reg property that you seem to be abandoning here... > > So for devices that come in multiple RAM configurations - like R-Box Pro > - this would require separate .dts files now! This looks very wrong to > me, especially since I am not aware of other platforms doing the same. > Instead, there's memory reservations for top and bottom done in U-Boot > for reg, plus reserved-memory nodes for anything in the middle. > > Another thing to consider is that uEFI boot (bootefi) handles memory > reservation differently yet again, on the bootloader level. I have had > that working fine on Odroid-C2 and Vega S95. > > So if there's no bug this is fixing (none mentioned in commit message) I > strongly object to this patch. > > Regards, > Andreas > Hi Andreas, Like I replied of my RFT patch : I really disagree about relying on any work or properties added by any bootloader here, Amlogic SoCs has a lot of u-boot versions in the field, and the Odroid-C2 is part of this. Even if Odroid-c2 is in mainline U-Boot or not, the mainline Linux kernel should work using any U-boot version even with the one provided by Amlogic on their openlinux distribution channel. Handling multiple RAM configuration is another story, and the Arm-Soc and DT maintainers should give us their advices. Actually there is a severe bug fixed here that cause a huge crash if such memory is not reserved while running stock u-boot version on various shipped products and Amlogic's own development boards. The bug is easily triggered by running : # stress --vm 4 --vm-bytes 128M --timeout 10s & [ 46.937975] Bad mode in Error handler detected on CPU1, code 0xbf000000 -- SError ... [ 47.058536] Internal error: Attempting to execute userspace memory: 8600000f [#3] PREEMPT SMP ... Note this is a fix targeted for 4.10 to make the system stable and various users reported some severe crash now the system has more drivers and read-world use-cases are running on Amlogic SoCs. Please feel free to push whatever changes that makes this memory reservation more coherent for 4.11, and respect the behavior of already shipped u-boot version and mainline U-Boot, UEFI, whatever... Neil