Re: [PATCH v2] microblaze: Change NO_IRQ to 0

[Michal Simek]

> > 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@xxxxxxxxxxxx>
> > Signed-off-by: Rob Herring <rob.herring@xxxxxxxxxxx>
> > Signed-off-by: Michal Simek <monstr@xxxxxxxxx>
>
> <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?

yeah, there are some drivers which we share with ppc.
I will look at/fix them and then remove NO_IRQ from arch.

drivers/net/ethernet/xilinx/xilinx_emaclite.c:1132:     if (rc == NO_IRQ) {
drivers/net/ethernet/xilinx/ll_temac_main.c:1080:       if ((lp->rx_irq == NO_IRQ) || (lp->tx_irq == NO_IRQ)) {
drivers/input/serio/xilinx_ps2.c:256:   if (of_irq_to_resource(ofdev->dev.of_node, 0, &r_irq) == NO_IRQ) {
drivers/block/xsysace.c:459:    if (ace->irq == NO_IRQ)
drivers/block/xsysace.c:1037:   if (ace->irq != NO_IRQ) {
drivers/block/xsysace.c:1042:                   ace->irq = NO_IRQ;
drivers/block/xsysace.c:1089:   if (ace->irq != NO_IRQ)
drivers/block/xsysace.c:1159:   int irq = NO_IRQ;

Thanks,
Michal

--
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian
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