From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753407AbbGGH2t (ORCPT ); Tue, 7 Jul 2015 03:28:49 -0400 Received: from mail-wg0-f54.google.com ([74.125.82.54]:35317 "EHLO mail-wg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750760AbbGGH2k (ORCPT ); Tue, 7 Jul 2015 03:28:40 -0400 Message-ID: <559B7FA2.4080005@gmail.com> Date: Tue, 07 Jul 2015 09:28:34 +0200 From: Sebastian Hesselbarth User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 To: Jisheng Zhang , linux@arm.linux.org.uk CC: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, antoine.tenart@free-electrons.com Subject: Re: [PATCH 0/2] arm: berlin: add cpu hotplug support References: <1436253035-371-1-git-send-email-jszhang@marvell.com> In-Reply-To: <1436253035-371-1-git-send-email-jszhang@marvell.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/07/2015 09:10 AM, Jisheng Zhang wrote: > These patches try to add cpu hotplug support for Marvell BG2, BG2Q SoCs. > These SoCs can't power off cpu independently, but we still want cpu hotplug > support for them. However, we need to address "CPU still sat on kernel text" > as pointed out by Mark Rutland[1]. We achieved this by putting the dying CPU > in WFI state after the coherency is disabled, then asserting the dying CPU > reset bit to put the CPU in reset state. Jisheng, thanks for the patches! Out of curiosity, did you measure overall SoC power consumption with WFI and with reset respectively? I'd expect a slightly _higher_ power consumption while in reset depending on clock gating applied to the processor hardware. Sebastian > patch1 use non-self-cleared control register to reset cpu. This is to prepare > for the next cpu hotplug commit. > > patch2 adds the cpu hotplug support finally. > > > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-May/342642.html > > Jisheng Zhang (2): > arm: berlin: use non-self-cleared reset register to reset cpu > arm: berlin: add CPU hotplug support > > arch/arm/mach-berlin/platsmp.c | 29 ++++++++++++++++++++++++++++- > 1 file changed, 28 insertions(+), 1 deletion(-) >