From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752511AbeBZPyJ (ORCPT ); Mon, 26 Feb 2018 10:54:09 -0500 Received: from out2-smtp.messagingengine.com ([66.111.4.26]:42033 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752168AbeBZPyG (ORCPT ); Mon, 26 Feb 2018 10:54:06 -0500 X-ME-Sender: Subject: Re: [PATCH v3 6/7] arm64: allwinner: h6: add the basical Allwinner H6 DTSI file To: Maxime Ripard , Icenowy Zheng Cc: Chen-Yu Tsai , Linus Walleij , linux-clk@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-sunxi@googlegroups.com References: <20180223123555.64009-6-icenowy@aosc.io> <20180223123555.64009-7-icenowy@aosc.io> <20180223152038.2bflylwa6vj4gzfj@flea.lan> <81D53DC5-7622-430E-A530-ED0DE5397DC3@aosc.io> <20180226092645.xghkmfowenzlbm42@flea.lan> From: Samuel Holland Message-ID: Date: Mon, 26 Feb 2018 09:54:01 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <20180226092645.xghkmfowenzlbm42@flea.lan> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/26/18 03:26, Maxime Ripard wrote: > On Fri, Feb 23, 2018 at 11:22:06PM +0800, Icenowy Zheng wrote: >>>> + psci { >>>> + compatible = "arm,psci-0.2"; >>>> + method = "smc"; >>>> + }; >>> >>> Is it needed? The bootloader should fill it with whatever version it >>> has, shouldn't it? >> >> But we now use ATF rather than U-Boot PSCI. U-Boot will not fill ATF >> info. >> >> See A64/H5 device trees. > > So if the PSCI version implemented in ATF ever changes, we would have > to update all the DT everywhere, but only if you're running the new > version? Yes but no. PSCI 1.0 is generally backward compatible with PSCI 0.2. In fact, the Linux driver treats them exactly the same: { .compatible = "arm,psci-0.2", .data = psci_0_2_init}, { .compatible = "arm,psci-1.0", .data = psci_0_2_init}, For the H6, however, the oldest ATF source available (which I believe was the one in use during bringup) is based on mainline 1.4, and is already at PSCI version 1.1: [ 0.000000] psci: probing for conduit method from DT. [ 0.000000] psci: PSCIv1.1 detected in firmware. [ 0.000000] psci: Using standard PSCI v0.2 function IDs [ 0.000000] psci: MIGRATE_INFO_TYPE not supported. So we could go ahead and bump the compatible to "arm,psci-1.0". Thanks, Samuel