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ARM: 6532/1: Allow machine to specify it's own IRQ handlers at run-time

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Normally different ARM platform has different way to decode the IRQ
hardware status and demultiplex to the corresponding IRQ handler.
This is highly optimized by macro irq_handler in entry-armv.S, and
each machine defines their own macro to decode the IRQ number.
However, this prevents multiple machine classes to be built into a
single kernel.

By allowing each machine to specify thier own handler, and making
function pointer 'handle_arch_irq' to point to it at run time, this
can be solved. And introduce CONFIG_MULTI_IRQ_HANDLER to allow both
solutions to work.

Comparing with the highly optimized macro of irq_handler, the new
function must be written with care not to lose too much performance.
And the IPI stuff on SMP is expected to move to the provided arch
IRQ handler as well.

The assembly code to invoke handle_arch_irq is optimized by Russell
King.

Signed-off-by: Eric Miao <eric.miao@canonical.com>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
eric miao 2010-12-13 09:42:34 +01:00 committed by Russell King
parent 4a50bfe365
commit 521086412e
5 changed files with 30 additions and 2 deletions
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5
arch/arm/Kconfig
View File

@ -1022,6 +1022,11 @@ 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

3
arch/arm/include/asm/mach/arch.h
View File

@ -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
};
/*

4
arch/arm/include/asm/mach/irq.h
View File

@ -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
*/

17
arch/arm/kernel/entry-armv.S
View File

@ -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

3
arch/arm/kernel/setup.c
View File

@ -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)