entry-macro.s

LINUX 2.6.17.4的源码

/*
 * include/asm-arm/arch-s3c2410/entry-macro.S
 *
 * Low-level IRQ helper macros for S3C2410-based platforms
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
*/

/* We have a problem that the INTOFFSET register does not always
 * show one interrupt. Occasionally we get two interrupts through
 * the prioritiser, and this causes the INTOFFSET register to show
 * what looks like the logical-or of the two interrupt numbers.
 *
 * Thanks to Klaus, Shannon, et al for helping to debug this problem
*/

#define INTPND		(0x10)
#define INTOFFSET	(0x14)
#define EXTINTPEND	(0xa8)
#define EXTINTMASK	(0xa4)

#include <asm/hardware.h>
#include <asm/arch/irqs.h>

	.macro	get_irqnr_and_base, irqnr, irqstat, base, tmp

		mov	\base, #S3C24XX_VA_IRQ

		ldr	\irqstat, [ \base, #INTPND]
		bics	\irqnr, \irqstat, #3<<4		@@ only an GPIO IRQ
		beq	2000f

		@@ try the interrupt offset register, since it is there

		ldr	\irqnr, [ \base, #INTOFFSET ]
		mov	\tmp, #1
		tst	\irqstat, \tmp, lsl \irqnr
		addne	\irqnr, \irqnr, #IRQ_EINT0
		bne	1001f

		@@ the number specified is not a valid irq, so try
		@@ and work it out for ourselves

		mov	\irqnr, #IRQ_EINT0		@@ start here
		b	3000f

2000:
		@@ load the GPIO interrupt register, and check it

		add	\tmp, \base, #S3C24XX_VA_GPIO - S3C24XX_VA_IRQ
		ldr	\irqstat, [ \tmp, # EXTINTPEND ]
		ldr	\irqnr,   [ \tmp, # EXTINTMASK ]
		bics	\irqstat, \irqstat, \irqnr
		beq	1001f

		mov	\irqnr, #(IRQ_EINT4 - 4)

		@@ work out which irq (if any) we got
3000:
		movs	\tmp, \irqstat, lsl#16
		addeq	\irqnr, \irqnr, #16
		moveq	\irqstat, \irqstat, lsr#16
		tst	\irqstat, #0xff
		addeq	\irqnr, \irqnr, #8
		moveq	\irqstat, \irqstat, lsr#8
		tst	\irqstat, #0xf
		addeq	\irqnr, \irqnr, #4
		moveq	\irqstat, \irqstat, lsr#4
		tst	\irqstat, #0x3
		addeq	\irqnr, \irqnr, #2
		moveq	\irqstat, \irqstat, lsr#2
		tst	\irqstat, #0x1
		addeq	\irqnr, \irqnr, #1

		@@ we have the value
		movs	\irqnr, \irqnr

1001:
		@@ exit here, Z flag unset if IRQ

	.endm

		/* currently don't need an disable_fiq macro */

		.macro	disable_fiq
		.endm