powerpc: Remove all usages of NO_IRQ

NO_IRQ has been == 0 on powerpc for just over ten years (since commit
0ebfff1491ef ("[POWERPC] Add new interrupt mapping core and change
platforms to use it")). It's also 0 on most other arches.

Although it's fairly harmless, every now and then it causes confusion
when a driver is built on powerpc and another arch which doesn't define
NO_IRQ. There's at least 6 definitions of NO_IRQ in drivers/, at least
some of which are to work around that problem.

So we'd like to remove it. This is fairly trivial in the arch code, we
just convert:

    if (irq == NO_IRQ)	to	if (!irq)
    if (irq != NO_IRQ)	to	if (irq)
    irq = NO_IRQ;	to	irq = 0;
    return NO_IRQ;	to	return 0;

And a few other odd cases as well.

At least for now we keep the #define NO_IRQ, because there is driver
code that uses NO_IRQ and the fixes to remove those will go via other
trees.

Note we also change some occurrences in PPC sound drivers, drivers/ps3,
and drivers/macintosh.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/powerpc/sysdev/fsl_mpic_err.c b/arch/powerpc/sysdev/fsl_mpic_err.c
index b83f32562a37..488ec453038a 100644
--- a/arch/powerpc/sysdev/fsl_mpic_err.c
+++ b/arch/powerpc/sysdev/fsl_mpic_err.c
@@ -115,8 +115,8 @@ static irqreturn_t fsl_error_int_handler(int irq, void *data)
 		errint = __builtin_clz(eisr);
 		cascade_irq = irq_linear_revmap(mpic->irqhost,
 				 mpic->err_int_vecs[errint]);
-		WARN_ON(cascade_irq == NO_IRQ);
-		if (cascade_irq != NO_IRQ) {
+		WARN_ON(!cascade_irq);
+		if (cascade_irq) {
 			generic_handle_irq(cascade_irq);
 		} else {
 			eimr |=  1 << (31 - errint);
@@ -134,7 +134,7 @@ void mpic_err_int_init(struct mpic *mpic, irq_hw_number_t irqnum)
 	int ret;
 
 	virq = irq_create_mapping(mpic->irqhost, irqnum);
-	if (virq == NO_IRQ) {
+	if (!virq) {
 		pr_err("Error interrupt setup failed\n");
 		return;
 	}