From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryan Mallon Subject: Re: [PATCH v2] microblaze: Change NO_IRQ to 0 Date: Tue, 20 Dec 2011 10:06:52 +1100 Message-ID: <4EEFC38C.4010201@gmail.com> References: <1324304394-5655-1-git-send-email-monstr@monstr.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1324304394-5655-1-git-send-email-monstr@monstr.eu> Sender: linux-kernel-owner@vger.kernel.org To: Michal Simek Cc: linux-kernel@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, Grant Likely , Rob Herring List-Id: devicetree@vger.kernel.org On 20/12/11 01:19, Michal Simek wrote: > As has been discussed many times[1], Using NO_IRQ set to anything other > than 0 is bug waiting to happen since many drivers follow the pattern > "if (!irq)" for testing whether or not an irq has been set. > > This patch changes the Microblaze NO_IRQ setting from -1 to 0 to bring > it in line with most of the rest of the kernel. It also prepares for > Microblaze eventually supporting multiple interrupt controllers by > breaking the assumption that hwirq# == Linux IRQ#. The Linux IRQ > number is just a cookie with no guarantee of a direct relationship > with the hardware irq arrangement. > > At this point, Microblaze interrupt handling only supports only one > instance of one kind of interrupt controller (xilinx_intc). This change > shouldn't affect any architecture code outside of the interrupt > controller driver and the irq_of mapping. > > Updated to 3.2 and to use irq_data.hwirq by Rob Herring. > Tested and fixed by Michal Simek. > > [1] http://lkml.org/lkml/2005/11/21/221 > > Signed-off-by: Grant Likely > Signed-off-by: Rob Herring > Signed-off-by: Michal Simek > extern unsigned int nr_irq; > > -#define NO_IRQ (-1) > +#define NO_IRQ 0 IIUC, NO_IRQ should actually be removed in favour of testing against zero explictly. On Linus' latest tree there are three appearances of NO_IRQ in arch/microblaze: this definition and two uses and arch/microblaze/pci/pci-common.c. The latter should be removed by this patch. I assume there are still uses of NO_IRQ in drivers used by microblaze which prevent removal of NO_IRQ completely? ~Ryan