[RFC PATCH 18/24] arm: irq: do not assume NR_IRQS to be defined

[Nicolas Pitre]

On Tue, 23 Aug 2011, Venkatraman S wrote:

> From: Venkatraman S <venkat at linaro.org>
> 
> If SPARSE_IRQ is defined, NR_IRQS will not necessarily be
> relevant. Use the number populated in machine descriptor.
> 
> Note: HARDIRQ_BITS is defined as a constant independent of NR_IRQS.
> Needs review if this assumption makes sense.
> 
> Signed-off-by: Venkatraman S <venkat at linaro.org>

This could be posted to LAK for further comments too.



> ---
>  arch/arm/common/gic.c          |    8 ++++----
>  arch/arm/include/asm/hardirq.h |    6 ++++++
>  arch/arm/kernel/irq.c          |    8 +++++++-
>  3 files changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
> index 4ddd0a6..6fb5fa4 100644
> --- a/arch/arm/common/gic.c
> +++ b/arch/arm/common/gic.c
> @@ -28,7 +28,7 @@
>  #include <linux/smp.h>
>  #include <linux/cpumask.h>
>  #include <linux/io.h>
> -
> +#include <linux/irqnr.h>
>  #include <asm/irq.h>
>  #include <asm/mach/irq.h>
>  #include <asm/hardware/gic.h>
> @@ -231,7 +231,7 @@ static void gic_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
>  		goto out;
>  
>  	cascade_irq = gic_irq + chip_data->irq_offset;
> -	if (unlikely(gic_irq < 32 || gic_irq > 1020 || cascade_irq >= NR_IRQS))
> +	if (unlikely(gic_irq < 32 || gic_irq > 1020 || cascade_irq >= nr_irqs))
>  		do_bad_IRQ(cascade_irq, desc);
>  	else
>  		generic_handle_irq(cascade_irq);
> @@ -312,8 +312,8 @@ static void __init gic_dist_init(struct gic_chip_data *gic,
>  	 * Limit number of interrupts registered to the platform maximum
>  	 */
>  	irq_limit = gic->irq_offset + gic_irqs;
> -	if (WARN_ON(irq_limit > NR_IRQS))
> -		irq_limit = NR_IRQS;
> +	if (WARN_ON(irq_limit > nr_irqs))
> +		irq_limit = nr_irqs;
>  
>  	/*
>  	 * Setup the Linux IRQ subsystem.
> diff --git a/arch/arm/include/asm/hardirq.h b/arch/arm/include/asm/hardirq.h
> index 89ad180..4bea5c0 100644
> --- a/arch/arm/include/asm/hardirq.h
> +++ b/arch/arm/include/asm/hardirq.h
> @@ -30,6 +30,10 @@ u64 smp_irq_stat_cpu(unsigned int cpu);
>  
>  #define arch_irq_stat_cpu	smp_irq_stat_cpu
>  
> +#ifndef NR_IRQS
> +/* FIXME: Need a better way to derive HARDIRQ_BITS */
> +#define HARDIRQ_BITS 10
> +#else
>  #if NR_IRQS > 512
>  #define HARDIRQ_BITS	10
>  #elif NR_IRQS > 256
> @@ -47,6 +51,8 @@ u64 smp_irq_stat_cpu(unsigned int cpu);
>  # error HARDIRQ_BITS is too low!
>  #endif
>  
> +#endif
> +
>  #define __ARCH_IRQ_EXIT_IRQS_DISABLED	1
>  
>  #endif /* __ASM_HARDIRQ_H */
> diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
> index 83bbad0..12ffa9d 100644
> --- a/arch/arm/kernel/irq.c
> +++ b/arch/arm/kernel/irq.c
> @@ -124,7 +124,13 @@ void __init init_IRQ(void)
>  #ifdef CONFIG_SPARSE_IRQ
>  int __init arch_probe_nr_irqs(void)
>  {
> -	nr_irqs = machine_desc->nr_irqs ? machine_desc->nr_irqs : NR_IRQS;
> +	if (machine_desc->nr_irqs)
> +		nr_irqs = machine_desc->nr_irqs;
> +	#ifdef NR_IRQS
> +	else
> +		nr_irqs = NR_IRQS;
> +	#endif
> +	WARN_ON(nr_irqs);
>  	return nr_irqs;
>  }
>  #endif
> -- 
> 1.7.1
>