Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753418AbaFCGWi (ORCPT ); Tue, 3 Jun 2014 02:22:38 -0400 Received: from mx0a-0016f401.pphosted.com ([67.231.148.174]:46513 "EHLO mx0a-0016f401.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751740AbaFCGWg convert rfc822-to-8bit (ORCPT ); Tue, 3 Jun 2014 02:22:36 -0400 Date: Tue, 3 Jun 2014 14:19:13 +0800 From: Jisheng Zhang To: Antoine =?UTF-8?B?VMOpbmFydA==?= CC: Andrew Lunn , "sebastian.hesselbarth@gmail.com" , "thomas.petazzoni@free-electrons.com" , Jimmy Xu , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "alexandre.belloni@free-electrons.com" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 1/5] ARM: berlin: add SMP support Message-ID: <20140603141913.710a1f7e@xhacker> In-Reply-To: <20140602102750.GB13681@kwain> References: <1401700866-24804-1-git-send-email-antoine.tenart@free-electrons.com> <1401700866-24804-2-git-send-email-antoine.tenart@free-electrons.com> <20140602094715.GG28090@lunn.ch> <20140602100048.GA12162@kwain> <20140602100332.GH28090@lunn.ch> <20140602102750.GB13681@kwain> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.23; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.12.52,1.0.14,0.0.0000 definitions=2014-06-02_02:2014-06-02,2014-06-02,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1402240000 definitions=main-1406030087 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrew, Antoine, On Mon, 2 Jun 2014 03:27:50 -0700 Antoine Ténart wrote: > On Mon, Jun 02, 2014 at 12:03:32PM +0200, Andrew Lunn wrote: > > On Mon, Jun 02, 2014 at 12:00:48PM +0200, Antoine Ténart wrote: > > > Hi Andrew, > > > > > > On Mon, Jun 02, 2014 at 11:47:15AM +0200, Andrew Lunn wrote: > > > > On Mon, Jun 02, 2014 at 11:21:02AM +0200, Antoine Ténart wrote: > > > > > + > > > > > +static inline void berlin_reset_cpu(unsigned int cpu) > > > > > +{ > > > > > + u32 val; > > > > > + > > > > > + val = readl(cpu_ctrl + CPU_RESET); > > > > > + val |= BIT(cpu_logical_map(cpu)); > > > > > + writel(val, cpu_ctrl + CPU_RESET); > > > > > +} > > > > > > > > Is this performing a reset on the CPU, or is it taking it out of > > > > reset? > > > > > > > > If you are going to implement CPU hotplug at some point, you are going > > > > to want to be able to put the CPU into reset, i.e. power it off, and > > > > take it out of reset, i.e. power it on and getting it running. So it > > > > might help if we get these function names clear now. > > > > > > It is performing a reset on the CPU. berlin_perform_reset_cpu() then? > > > > What happens if the CPU is powered off? Will a reset power it on? Or > > are you assuming the boot loader has powered it on? > > I actually don't have information about this. For now let's assume the > boot loader has powered on the CPUs. > We don't support independently power off cpu on BG2 and BG2Q in linux kernel. So we can assume that bootloader has powered on the CPUs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/