From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751308AbeDYHHf (ORCPT ); Wed, 25 Apr 2018 03:07:35 -0400 Received: from foss.arm.com ([217.140.101.70]:34790 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750929AbeDYHHe (ORCPT ); Wed, 25 Apr 2018 03:07:34 -0400 Subject: Re: Affinity for GIC irq line To: valmiki , linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, jason@lakedaemon.net, Catalin Marinas References: <2880aee6-704c-a5aa-e193-75bba1bce43d@gmail.com> From: Marc Zyngier Organization: ARM Ltd Message-ID: <2d9f0678-ec5c-2b09-7ddd-407dd37c55a1@arm.com> Date: Wed, 25 Apr 2018 08:07:31 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <2880aee6-704c-a5aa-e193-75bba1bce43d@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/04/18 04:23, valmiki wrote: > Hi all, > > When an IRQ line is set affinity using irq_set_affinity, which calls > irq_do_set_affinity, this API copies affinity mask to affinity variable > in irq_common_data of this irq descriptor. It does a wee bit more. Crucially, it contains the line: ret = chip->irq_set_affinity(data, mask, force); > But as per ARM GICv2 document in order to drive a interrupt to a > specific CPU we need to program GICD_ITARGETSRn register. > > But irq_set_affinity isn't writing to this register.Please correct me if > I'm wrong i did not find code for this register being updated in > irq_set_affinity flow. > So how affinity is being set for an IRQ line ? I would have though that a function name such as "gic_set_affinity" was clear enough? > If affinity was set successfully on what CPU does asm_do_IRQ run ? It runs on the CPU that the interrupt targets, I'd say. M. -- Jazz is not dead. It just smells funny...