ARM: 8227/1: sa1100: switch to MULTI_IRQ_HANDLER

Add sa1100_handle_irq implementating handle_irq for sa1100 platform.
It is more or less a translation of old assembly code from assembler to
plain C. Also install this irq handler from sa1100_init_irq().

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -703,6 +703,7 @@ config ARCH_SA1100
 	select GENERIC_CLOCKEVENTS
 	select HAVE_IDE
 	select ISA
+	select MULTI_IRQ_HANDLER
 	select NEED_MACH_MEMORY_H
 	select SPARSE_IRQ
 	help

arch/arm/mach-sa1100/irq.c

@@ -20,6 +20,7 @@
 #include <mach/hardware.h>
 #include <mach/irqs.h>
 #include <asm/mach/irq.h>
+#include <asm/exception.h>
 
 #include "generic.h"
 
@@ -291,6 +292,23 @@ static int __init sa1100irq_init_devicefs(void)
 
 device_initcall(sa1100irq_init_devicefs);
 
+static asmlinkage void __exception_irq_entry
+sa1100_handle_irq(struct pt_regs *regs)
+{
+	uint32_t icip, icmr, mask;
+
+	do {
+		icip = (ICIP);
+		icmr = (ICMR);
+		mask = icip & icmr;
+
+		if (mask == 0)
+			break;
+
+		handle_IRQ(ffs(mask) - 1 + IRQ_GPIO0, regs);
+	} while (1);
+}
+
 void __init sa1100_init_irq(void)
 {
 	unsigned int irq;
@@ -338,5 +356,7 @@ void __init sa1100_init_irq(void)
 	irq_set_chip(IRQ_GPIO11_27, &sa1100_normal_chip);
 	irq_set_chained_handler(IRQ_GPIO11_27, sa1100_high_gpio_handler);
 
+	set_handle_irq(sa1100_handle_irq);
+
 	sa1100_init_gpio();
 }