From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754618Ab2BEAB4 (ORCPT ); Sat, 4 Feb 2012 19:01:56 -0500 Received: from gate.crashing.org ([63.228.1.57]:50126 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754497Ab2BEABz (ORCPT ); Sat, 4 Feb 2012 19:01:55 -0500 Message-ID: <1328400065.30631.9.camel@pasglop> Subject: Re: [PATCH v3 00/25] irq_domain generalization and refinement From: Benjamin Herrenschmidt To: Russell King - ARM Linux Cc: Grant Likely , linux-kernel@vger.kernel.org, Thomas Gleixner , Milton Miller , Rob Herring , Stephen Rothwell , devicetree-discuss@lists.ozlabs.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Date: Sun, 05 Feb 2012 11:01:05 +1100 In-Reply-To: <20120204221748.GN14129@n2100.arm.linux.org.uk> References: <1327700179-17454-1-git-send-email-grant.likely@secretlab.ca> <20120204221748.GN14129@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.2- Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2012-02-04 at 22:17 +0000, Russell King - ARM Linux wrote: > On Fri, Jan 27, 2012 at 02:35:54PM -0700, Grant Likely wrote: > > Hey everyone, > > > > This patch series is ready for much wider consumption now. I'd like > > to get it into linux-next ASAP because there will be ARM board support > > depending on it. I'll wait a few days before I ask Stephen to pull > > this in. > > Grant, > > Can you answer me this: does this irqdomain support require DT? The original powerpc code this is based on didn't require it. It was an explicit design decision and I remember insisting that Grant follows it, but I haven't yet reviewed his last batch. DT is orthogonal. You have "helpers" that use the DT to resolve the domain of an interrupt source and do the mapping for you, but I made sure that you call always still create domains and map interrupts using explicit domain pointers & hw numbers. (And I need them to deal with ancient broken device-tree's on some platforms such as oldworld PowerMacs). > The question comes up because OMAP has converted some of their support > to require irq domain support for their PMICs, and it seems irq domain > support requires DT. This seems to have made the whole of OMAP > essentially become a DT-only platform. .../... > Now, here's the thing: I believe that IRQ domains - at least as far as > the hwirq stuff - should be available irrespective of whether we have > the rest of the IRQ domain support code in place, so that IRQ support > code doesn't have to keep playing games to decode from the global > space to the per-controller number space. > > I believe that would certainly help the current OMAP problems, where > the current lack of CONFIG_IRQ_DOMAIN basically makes the kernel oops > on boot. > > How we fix this regression for 3.4 I've no idea at present, I'm trying > to work out what the real dependencies are for OMAP on this stuff. > > Finally, do we need asm/irq.h in our asm/prom.h ? That's causing > fragility between DT and non-DT builds, because people are finding > that their DT builds work without their mach/irqs.h includes but > fail when built with non-DT. The only thing which DT might need - > at the most - is NR_IRQS, but I'd hope with things like irq domains > it doesn't actually require it. Cheers, Ben.