Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755784AbcJZQRr (ORCPT ); Wed, 26 Oct 2016 12:17:47 -0400 Received: from smtprelay.synopsys.com ([198.182.47.9]:35944 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755004AbcJZQRp (ORCPT ); Wed, 26 Oct 2016 12:17:45 -0400 Subject: Re: [PATCH v2 4/5] ARC: MCIP: Set an initial affinity value in idu_irq_map To: Marc Zyngier , Yuriy Kolerov , References: <1477313194-2310-1-git-send-email-yuriy.kolerov@synopsys.com> <1477313194-2310-4-git-send-email-yuriy.kolerov@synopsys.com> <39eae1ef-85d1-6dfb-b9fc-a052012c1fbf@synopsys.com> <127dbe3b-c9a9-3718-a711-128505ee363f@arm.com> CC: , , Newsgroups: gmane.linux.kernel,gmane.linux.kernel.arc From: Vineet Gupta Message-ID: Date: Wed, 26 Oct 2016 09:17:34 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <127dbe3b-c9a9-3718-a711-128505ee363f@arm.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.10.161.43] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 611 Lines: 13 On 10/26/2016 07:05 AM, Marc Zyngier wrote: > It definitely feels weird to encode the interrupt affinity in the DT > (the kernel and possible userspace usually know much better than the > firmware). What is the actual reason for storing the affinity there? The IDU intc supports various interrupt distribution modes (Round Robin, send to one cpu only etc) whcih in turn map to affinity setting. When doing the DT binding, we decided to add that this to DT to get the "seed" value for affinity - which user could optionally changed after boot. This seemed like a benign design choice at the time. Thx, -Vineet