From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751321AbcABK2M (ORCPT ); Sat, 2 Jan 2016 05:28:12 -0500 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:35516 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750923AbcABK2K (ORCPT ); Sat, 2 Jan 2016 05:28:10 -0500 Date: Sat, 2 Jan 2016 10:27:47 +0000 From: Russell King - ARM Linux To: Eric Anholt Cc: linux-rpi-kernel@lists.infradead.org, Florian Fainelli , Jason Cooper , Stephen Warren , Marc Zyngier , Lee Jones , linux-kernel@vger.kernel.org, Andrea Merello , Thomas Gleixner , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/4] irqchip: bcm2836: Add SMP support for the 2836 Message-ID: <20160102102747.GO8644@n2100.arm.linux.org.uk> References: <1451166444-11044-1-git-send-email-eric@anholt.net> <1451166444-11044-3-git-send-email-eric@anholt.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1451166444-11044-3-git-send-email-eric@anholt.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Dec 26, 2015 at 01:47:22PM -0800, Eric Anholt wrote: > +int __init bcm2836_smp_boot_secondary(unsigned int cpu, > + struct task_struct *idle) > +{ > + unsigned long secondary_startup_phys = > + (unsigned long)virt_to_phys((void *)secondary_startup); > + > + dsb(); > + writel(secondary_startup_phys, > + intc.base + LOCAL_MAILBOX3_SET0 + 16 * cpu); Please explain why you need this dsb() - I can't see a reason for it. writel() has a barrier internally prior to writing the register, and therefore I think the above dsb() is entirely redundant. -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.