ACPI: create /sys/firmware/acpi/interrupts

See Documentation/ABI/testing/sysfs-firmware-acpi

Based-on-original-patch-by: Luming Yu <luming.yu@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/osl.c

@@ -332,7 +332,15 @@ acpi_os_table_override(struct acpi_table_header * existing_table,
 
 static irqreturn_t acpi_irq(int irq, void *dev_id)
 {
-	return (*acpi_irq_handler) (acpi_irq_context) ? IRQ_HANDLED : IRQ_NONE;
+	u32 handled;
+
+	handled = (*acpi_irq_handler) (acpi_irq_context);
+
+	if (handled) {
+		acpi_irq_handled++;
+		return IRQ_HANDLED;
+	} else
+		return IRQ_NONE;
 }
 
 acpi_status
@@ -341,6 +349,8 @@ acpi_os_install_interrupt_handler(u32 gsi, acpi_osd_handler handler,
 {
 	unsigned int irq;
 
+	acpi_irq_stats_init();
+
 	/*
 	 * Ignore the GSI from the core, and use the value in our copy of the
 	 * FADT. It may not be the same if an interrupt source override exists