From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17F62C3279B for ; Fri, 6 Jul 2018 12:26:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A264A23D22 for ; Fri, 6 Jul 2018 12:26:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A264A23D22 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-sky.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932836AbeGFM0q (ORCPT ); Fri, 6 Jul 2018 08:26:46 -0400 Received: from smtp2200-217.mail.aliyun.com ([121.197.200.217]:39068 "EHLO smtp2200-217.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932732AbeGFM0o (ORCPT ); Fri, 6 Jul 2018 08:26:44 -0400 X-Alimail-AntiSpam: AC=CONTINUE;BC=0.07793569|-1;CH=green;FP=0|0|0|0|0|-1|-1|-1;HT=e01l01425;MF=ren_guo@c-sky.com;NM=1;PH=DS;RN=12;RT=12;SR=0;TI=SMTPD_---.CN5.Ucd_1530879991; Received: from localhost(mailfrom:ren_guo@c-sky.com fp:SMTPD_---.CN5.Ucd_1530879991) by smtp.aliyun-inc.com(10.147.40.233); Fri, 06 Jul 2018 20:26:31 +0800 Date: Fri, 6 Jul 2018 20:26:31 +0800 From: Guo Ren To: Mark Rutland Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, daniel.lezcano@linaro.org, jason@lakedaemon.net, arnd@arndb.de, c-sky_gcc_upstream@c-sky.com, gnu-csky@mentor.com, thomas.petazzoni@bootlin.com, wbx@uclibc-ng.org, green.hu@gmail.com Subject: Re: [PATCH V2 16/19] csky: SMP support Message-ID: <20180706122631.GA30265@guoren> References: <21d859826fe19aecaa2aefe3103d6d33e6f1b925.1530465326.git.ren_guo@c-sky.com> <20180706052432.q74gql32dtj5gj3b@salmiak> <20180706113200.GA27148@guoren> <20180706114352.6r7zkjunoafqtr3s@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180706114352.6r7zkjunoafqtr3s@lakrids.cambridge.arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 06, 2018 at 12:43:52PM +0100, Mark Rutland wrote: > Please see the devicetree spec [1], section 2.3.4. Valid values are: > > * "okay" // equivalent to no status property present > * "disabled" > * "fail" > * "fail-sss" Nice tip, thx. > I'm a bit confused. You write (1 << cpu) into cv<29, 0>, to enable a > particular CPU, so I assume that bit uniquely identifies a CPU, Yes, you're right and cr<29, 0>'s bit uniquely identifies a cpu. > and > therefore the reg is some unique ID for the CPU. static int csky_of_cpu(struct device_node *node) { const char *status; if (of_property_read_string(node, "status", &status)) status = "okay"; if (strcmp(status, "disabled") == 0) goto error; return 1; error: return 0; } void __init setup_smp(void) { struct device_node *node = NULL; int i = 0; while ((node = of_find_node_by_type(node, "cpu"))) { if (!csky_of_cpu(node)) continue; set_cpu_possible(i, true); set_cpu_present(i, true); i++; } } Hmm? No in next version patch, it's no use. > I see. > > Is this SMP bringup mechanism architectual, or are you likely to need > another mechanism to turn on CPUs on future chips? It's the only SMP bringup mechanism architectual for C-SKY SMP. There is no another way in future and SOC vendor couldn't change it. > You probably want to use an enable-method property to describe this. No, thx. Guo Ren