[RFC PATCH 3/3] [ARM] Allow boards to specify the exact number of IRQs needed

[ben-linux@fluff.org (Ben Dooks)]

On Thu, Feb 04, 2010 at 11:12:37AM -0800, Eric Miao wrote:
> commit 988a6a2bd322d83eba42c05cb6cb77a74cba056b
> Author: Eric Miao <eric.y.miao@gmail.com>
> Date:   Thu Feb 4 11:06:35 2010 -0800
> 
>     [ARM] Allow boards to specify the exact number of IRQs needed
> 
>     This will only take effect if SPARSE_IRQ is enabled, any board that
>     depends on this _only_ has to explicitly select SPARSE_IRQ.
> 
>     Signed-off-by: Eric Miao <eric.y.miao@gmail.com>

Is this going to cause errors when the core support tries to register
irq chips over the number that the board itself supports?
 
> diff --git a/arch/arm/include/asm/irq.h b/arch/arm/include/asm/irq.h
> index a1ea728..825ee34 100644
> --- a/arch/arm/include/asm/irq.h
> +++ b/arch/arm/include/asm/irq.h
> @@ -19,6 +19,7 @@
> 
>  #ifndef __ASSEMBLY__
>  struct irqaction;
> +extern int arch_nr_irqs;
>  extern void migrate_irqs(void);
> 
>  extern void asm_do_IRQ(unsigned int, struct pt_regs *);
> diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h
> index c59842d..a9128b4 100644
> --- a/arch/arm/include/asm/mach/arch.h
> +++ b/arch/arm/include/asm/mach/arch.h
> @@ -20,6 +20,7 @@ struct machine_desc {
>  	 * by assembler code in head.S, head-common.S
>  	 */
>  	unsigned int		nr;		/* architecture number	*/
> +	unsigned int		num_irqs;	/* number of IRQs */
>  	unsigned int		phys_io;	/* start of physical io	*/
>  	unsigned int		io_pg_offst;	/* byte offset for io
>  						 * page tabe entry	*/
> diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
> index e62f39b..e23d248 100644
> --- a/arch/arm/kernel/irq.c
> +++ b/arch/arm/kernel/irq.c
> @@ -168,7 +168,7 @@ void __init init_IRQ(void)
>  #ifdef CONFIG_SPARSE_IRQ
>  int __init arch_probe_nr_irqs(void)
>  {
> -	nr_irqs = NR_IRQS;
> +	nr_irqs = arch_nr_irqs ? arch_nr_irqs : NR_IRQS;
>  	return 0;
>  }
>  #endif
> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> index c6c57b6..803ed95 100644
> --- a/arch/arm/kernel/setup.c
> +++ b/arch/arm/kernel/setup.c
> @@ -755,6 +755,7 @@ void __init setup_arch(char **cmdline_p)
>  	/*
>  	 * Set up various architecture-specific pointers
>  	 */
> +	arch_nr_irqs = mdesc->num_irqs;
>  	init_arch_irq = mdesc->init_irq;
>  	system_timer = mdesc->timer;
>  	init_machine = mdesc->init_machine;
> 
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-- 
-- 
Ben

Q:      What's a light-year?
A:      One-third less calories than a regular year.