Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756704AbbHZNUT (ORCPT ); Wed, 26 Aug 2015 09:20:19 -0400 Received: from www.linutronix.de ([62.245.132.108]:55619 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752553AbbHZNUS (ORCPT ); Wed, 26 Aug 2015 09:20:18 -0400 Date: Wed, 26 Aug 2015 15:19:44 +0200 (CEST) From: Thomas Gleixner To: Qais Yousef cc: Marc Zyngier , "alsa-devel@alsa-project.org" , Jason Cooper , "linux-kernel@vger.kernel.org" , "linux-mips@linux-mips.org" , Mark Rutland Subject: Re: [PATCH 01/10] irqchip: irq-mips-gic: export gic_send_ipi In-Reply-To: <55DDA1C4.4070301@imgtec.com> Message-ID: References: <1440419959-14315-1-git-send-email-qais.yousef@imgtec.com> <1440419959-14315-2-git-send-email-qais.yousef@imgtec.com> <55DB15EB.3090109@imgtec.com> <55DB1CD2.5030300@arm.com> <55DB29B5.3010202@imgtec.com> <55DB48C9.7010508@imgtec.com> <55DB519D.2090203@arm.com> <55DDA1C4.4070301@imgtec.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2209 Lines: 55 On Wed, 26 Aug 2015, Qais Yousef wrote: > Can we replace 'something' in interrupt-source and interrupt-sink definitions > to 'host' or 'CPU' or do we really care about creating IPI between any 2 > 'things'? > > Changing the definition will also make interrupt-sink a synonym/alias to > interrupts property. So the description will become > > axd: axd { > interrupt-source = <&gic GIC_SHARED 36 IRQ_TYPE_EDGE_RISING>; /* > interrupt from CPU to AXD */ > interrupt-sink = <&gic GIC_SHARED 37 IRQ_TYPE_EDGE_RISING>; /* > interrupt from AXD to CPU */ > } > > But this assume Linux won't take care of the routing. If we want Linux to take > care of the routing, maybe something like this then? > > axd: axd { > interrupt-source = <&gic GIC_SHARED 36 IRQ_TYPE_EDGE_RISING > HWAFFINITY1>; /* interrupt from CPU to > AXD@HWAFFINITY1*/ > interrupt-sink = <&gic GIC_SHARED 37 IRQ_TYPE_EDGE_RISING > HWAFFINITY2>; /* interrupt from AXD to CPU@HWAFFINITY2 */ > } > > I don't think it's necessary to specify the HWAFFINITY2 for interrupt-sink as > linux can use SMP affinity to move it around but we can make it optional in > case there's a need to hardcode it to a specific Linux core. Or maybe the > driver can use affinity hint.. Wrong. You cannot move an IPI around with set_affinity. It's possible to send an IPI to more than one target CPU, but that has nothing to do with affinities. Are you talking about IPIs or about general interrupts which have an affinity setting? > Any pointers on the best way to tie gic_send_ipi() with the driver/core code? > The way it's currently tied to the core code is through SMP IPI functions > which I don't think we can use. I'm thinking adding a pointer function in > struct irq_chip would be the easiest approach maybe? That's the least of our worries. We need to get the high level interfaces and the devicetree mechanism straight before we talk about this kind of details. Thanks, tglx -- 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/