Messages in this thread | | | Date | Tue, 20 Dec 2011 10:06:52 +1100 | From | Ryan Mallon <> | Subject | Re: [PATCH v2] microblaze: Change NO_IRQ to 0 |
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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 <grant.likely@secretlab.ca> > Signed-off-by: Rob Herring <rob.herring@calxeda.com> > Signed-off-by: Michal Simek <monstr@monstr.eu>
<snip>
> 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
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