| Message ID | 20110318.150435.241941372.davem@davemloft.net |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
On Fri, Mar 18, 2011 at 03:04:35PM -0700, David Miller wrote: > > Signed-off-by: David S. Miller <davem@davemloft.net> > --- > arch/sparc/include/asm/irq_32.h | 3 +++ > arch/sparc/include/asm/irq_64.h | 2 ++ > 2 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/arch/sparc/include/asm/irq_32.h b/arch/sparc/include/asm/irq_32.h > index cbf4801..eced3e3 100644 > --- a/arch/sparc/include/asm/irq_32.h > +++ b/arch/sparc/include/asm/irq_32.h > @@ -13,4 +13,7 @@ > #define irq_canonicalize(irq) (irq) > > extern void __init init_IRQ(void); > + > +#define NO_IRQ 0xffffffff > + > #endif > diff --git a/arch/sparc/include/asm/irq_64.h b/arch/sparc/include/asm/irq_64.h > index 4f09666f..16dcae6d 100644 > --- a/arch/sparc/include/asm/irq_64.h > +++ b/arch/sparc/include/asm/irq_64.h > @@ -97,4 +97,6 @@ extern void *softirq_stack[NR_CPUS]; > #define __ARCH_HAS_DO_SOFTIRQ > #define ARCH_HAS_NMI_WATCHDOG > > +#define NO_IRQ 0xffffffff > + > #endif Why -1 (0xffffffff)? drivers/of/irq.c default to 0 - like this: /* For archs that don't support NO_IRQ (such as x86), provide a dummy value */ #ifndef NO_IRQ #define NO_IRQ 0 #endif I can see that the actual value differs from arch to arch. I recalled a discussion about this topic some years ago. Do not ask how I managed to do so?!? Anyway the input from Linus was to use 0 for NO_IRQ because as he said: ==== But the point is that most drivers will do something like if (!dev->irq) return; (whatever, made up). And that having NO_IRQ be anything but 0 is thus fundamentally broken. ==== See the full mail here: http://lkml.org/lkml/2005/11/21/211 I do not know of any places that would break - I just wanted to bring this to your attention. Sam -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Sam Ravnborg <sam@ravnborg.org> Date: Fri, 18 Mar 2011 23:48:10 +0100 > Why -1 (0xffffffff)? Because that is what the OF device object creation layer treats as no-IRQ. See for example the test in of_device_64.c:build_one_device_irq() where we go: if (irq == 0xffffffff) return irq; -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Mar 18, 2011 at 03:50:12PM -0700, David Miller wrote: > From: Sam Ravnborg <sam@ravnborg.org> > Date: Fri, 18 Mar 2011 23:48:10 +0100 > > > Why -1 (0xffffffff)? > > Because that is what the OF device object creation layer > treats as no-IRQ. > > See for example the test in of_device_64.c:build_one_device_irq() > where we go: > > if (irq == 0xffffffff) > return irq; Understood - thanks. Sam -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/sparc/include/asm/irq_32.h b/arch/sparc/include/asm/irq_32.h index cbf4801..eced3e3 100644 --- a/arch/sparc/include/asm/irq_32.h +++ b/arch/sparc/include/asm/irq_32.h @@ -13,4 +13,7 @@ #define irq_canonicalize(irq) (irq) extern void __init init_IRQ(void); + +#define NO_IRQ 0xffffffff + #endif diff --git a/arch/sparc/include/asm/irq_64.h b/arch/sparc/include/asm/irq_64.h index 4f09666f..16dcae6d 100644 --- a/arch/sparc/include/asm/irq_64.h +++ b/arch/sparc/include/asm/irq_64.h @@ -97,4 +97,6 @@ extern void *softirq_stack[NR_CPUS]; #define __ARCH_HAS_DO_SOFTIRQ #define ARCH_HAS_NMI_WATCHDOG +#define NO_IRQ 0xffffffff + #endif
Signed-off-by: David S. Miller <davem@davemloft.net> --- arch/sparc/include/asm/irq_32.h | 3 +++ arch/sparc/include/asm/irq_64.h | 2 ++ 2 files changed, 5 insertions(+), 0 deletions(-)