Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754790AbbHNKwu (ORCPT ); Fri, 14 Aug 2015 06:52:50 -0400 Received: from mail-ig0-f181.google.com ([209.85.213.181]:36638 "EHLO mail-ig0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754001AbbHNKws (ORCPT ); Fri, 14 Aug 2015 06:52:48 -0400 MIME-Version: 1.0 X-Originating-IP: [62.219.232.49] In-Reply-To: <20150813152508.GA4627@qualcomm.com> References: <1433867020-7746-1-git-send-email-lina.iyer@linaro.org> <20150627030514.GA893@linaro.org> <20150702203028.GA4711@linaro.org> <20150728215122.GE51847@linaro.org> <20150813152508.GA4627@qualcomm.com> From: Ohad Ben-Cohen Date: Fri, 14 Aug 2015 13:52:28 +0300 Message-ID: Subject: Re: [PATCH RFC v2 0/2] hwspinlock: Introduce raw capability for hwspinlock_device To: Andy Gross Cc: Lina Iyer , Bjorn Andersson , Jeffrey Hugo , "linux-arm-msm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1188 Lines: 25 On Thu, Aug 13, 2015 at 6:25 PM, Andy Gross wrote: > The issue in hardwiring this into the driver itself means forfeiting > extensibility. So on one side (w/ raw support), we get the ability to deal with > the lock number changing. On the other side (w/o raw), we'd have to probably > tie this to chip compat to figure out which lock is the 'special' if it ever > changes. It sounds like the decision "which lock to use" is a separate problem from "can it go raw". If the hardware doesn't prohibit raw mode, then every lock can be used in raw mode. So you just have to pick one and make sure both sides know which lock you use --- which is a classic multi-processor synchronization issue. > It's arbitrary right now. The remote processor selected a number, not the > processor running Linux. Is the number hardcoded right now? and you're using hwspin_lock_request_specific on the Linux side to acquire the lock? -- 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/