acpi/gsi: Always perform an irq domain lookup

Instead of directly passing NULL to the various irq_domain functions,
start by looking up the domain with a domain identifier..

As this identifier is permanently set to NULL, the lookup function will
return the same value (no domain found) and the default will be used,
preserving the current behaviour.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-and-tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: Tomasz Nowicki <tomasz.nowicki@linaro.org>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: Graeme Gregory <graeme@xora.org.uk>
Cc: Jake Oshins <jakeo@microsoft.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Link: http://lkml.kernel.org/r/1444737105-31573-10-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/acpi/gsi.c

@@ -11,9 +11,12 @@
 #include <linux/acpi.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
+#include <linux/of.h>
 
 enum acpi_irq_model_id acpi_irq_model;
 
+static struct fwnode_handle *acpi_gsi_domain_id;
+
 static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
 {
 	switch (polarity) {
@@ -45,12 +48,10 @@ static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
  */
 int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
 {
-	/*
-	 * Only default domain is supported at present, always find
-	 * the mapping corresponding to default domain by passing NULL
-	 * as irq_domain parameter
-	 */
-	*irq = irq_find_mapping(NULL, gsi);
+	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
+							DOMAIN_BUS_ANY);
+
+	*irq = irq_find_mapping(d, gsi);
 	/*
 	 * *irq == 0 means no mapping, that should
 	 * be reported as a failure
@@ -74,13 +75,10 @@ int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
 {
 	unsigned int irq;
 	unsigned int irq_type = acpi_gsi_get_irq_type(trigger, polarity);
+	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
+							DOMAIN_BUS_ANY);
 
-	/*
-	 * There is no way at present to look-up the IRQ domain on ACPI,
-	 * hence always create mapping referring to the default domain
-	 * by passing NULL as irq_domain parameter
-	 */
-	irq = irq_create_mapping(NULL, gsi);
+	irq = irq_create_mapping(d, gsi);
 	if (!irq)
 		return -EINVAL;
 
@@ -98,7 +96,9 @@ EXPORT_SYMBOL_GPL(acpi_register_gsi);
  */
 void acpi_unregister_gsi(u32 gsi)
 {
-	int irq = irq_find_mapping(NULL, gsi);
+	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
+							DOMAIN_BUS_ANY);
+	int irq = irq_find_mapping(d, gsi);
 
 	irq_dispose_mapping(irq);
 }