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

[Eric Miao]

On Sun, Dec 12, 2010 at 10:33 PM, Eric Miao <eric.y.miao at gmail.com> wrote:
> On Wed, Dec 8, 2010 at 9:41 PM, Russell King - ARM Linux
> <linux at arm.linux.org.uk> wrote:
>> 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
>>
>
> Updated the patch following your suggestions, verified on Marvell Dove
> platform and it worked all right. Do you want me to submit this to the
> patch tracking system?
>

(ignore my last mail with the wrong patch, my brain short circuited today,
here's the updated one):

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index db524e7..0cecffb 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1017,6 +1017,11 @@ config CPU_HAS_PMU
 	default y
 	bool

+config MULTI_IRQ_HANDLER
+	bool
+	help
+	  Allow each machine to specify it's own IRQ handler at run time.
+
 if !MMU
 source "arch/arm/Kconfig-nommu"
 endif
diff --git a/arch/arm/include/asm/mach/arch.h b/arch/arm/include/asm/mach/arch.h
index d97a964..7d55356 100644
--- a/arch/arm/include/asm/mach/arch.h
+++ b/arch/arm/include/asm/mach/arch.h
@@ -40,6 +40,9 @@ struct machine_desc {
 	void			(*init_irq)(void);
 	struct sys_timer	*timer;		/* system tick timer	*/
 	void			(*init_machine)(void);
+#ifdef CONFIG_MULTI_IRQ_HANDLER
+	void			(*handle_irq)(struct pt_regs *);
+#endif
 };

 /*
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..e6c08ac 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	r5, =handle_arch_irq
+	mov	r0, sp
+	ldr	r5, [r5]
+	adr	lr, BSYM(9997f)
+	teq	r5, #0
+	movne	pc, r5
+#endif
 	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:
+	.space	4
+#endif
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 336f14e..b809521 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -875,6 +875,9 @@ void __init setup_arch(char **cmdline_p)
 	init_arch_irq = mdesc->init_irq;
 	system_timer = mdesc->timer;
 	init_machine = mdesc->init_machine;
+#ifdef CONFIG_MULTI_IRQ_HANDLER
+	handle_arch_irq = mdesc->handle_irq;
+#endif

 #ifdef CONFIG_VT
 #if defined(CONFIG_VGA_CONSOLE)