[PATCH] ARM: Allow machine to specify it's own IRQ handlers at run-time

[Russell King - ARM Linux]

On Tue, Dec 07, 2010 at 09:31:11PM +0800, Eric Miao wrote:
> Ah silly me, the patch below fixed this, and tested on Marvell Dove:
...
> diff --git a/arch/arm/include/asm/mach/irq.h b/arch/arm/include/asm/mach/irq.h
> index ce3eee9..6ecdad9 100644
> --- a/arch/arm/include/asm/mach/irq.h
> +++ b/arch/arm/include/asm/mach/irq.h
> @@ -22,6 +22,10 @@ extern void (*init_arch_irq)(void);
>  extern void init_FIQ(void);
>  extern int show_fiq_list(struct seq_file *, void *);
> 
> +#ifdef CONFIG_MULTI_IRQ_HANDLER
> +extern void (*handle_arch_irq)(struct pt_regs *);
> +#endif
> +
>  /*
>   * This is for easy migration, but should be changed in the source
>   */
> diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
> index c09e357..d29e31b 100644
> --- a/arch/arm/kernel/entry-armv.S
> +++ b/arch/arm/kernel/entry-armv.S
> @@ -30,6 +30,14 @@
>   * Interrupt handling.  Preserves r7, r8, r9
>   */
>  	.macro	irq_handler
> +#ifdef CONFIG_MULTI_IRQ_HANDLER
> +	ldr	r1, =handle_arch_irq
> +	ldr	r0, [r1]
> +	cmp	r0, #0
> +	movne	r0, sp
> +	adrne	lr, BSYM(9997f)
> +	ldrne	pc, [r1]
> +#endif

You might as well do this:

	ldr	r5, =handle_arch_irq
	mov	r0, sp
	ldr	r5, [r5]
	adr	lr, BSYM(9997f)
	teq	r5, #0
	movne	pc, r5

which also helps to fill the load delay slots with useful work.

>  	get_irqnr_preamble r5, lr
>  1:	get_irqnr_and_base r0, r6, r5, lr
>  	movne	r1, sp
> @@ -58,9 +66,8 @@
>  	adrne	lr, BSYM(1b)
>  	bne	do_local_timer
>  #endif
> -9997:
>  #endif
> -
> +9997:
>  	.endm
> 
>  #ifdef CONFIG_KPROBES
> @@ -1245,3 +1252,9 @@ cr_alignment:
>  	.space	4
>  cr_no_alignment:
>  	.space	4
> +
> +#ifdef CONFIG_MULTI_IRQ_HANDLER
> +	.globl	handle_arch_irq
> +handle_arch_irq:
> +	.long	0

	.space 4

as above please