microblaze: Add irq_create_{of_,}mapping functions

Support function for PCI. We don't use any advance mapping mechanism
that's why implementation is simple.
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/include/asm/irq.h

@@ -14,6 +14,12 @@
 
 #include <linux/interrupt.h>
 
+/* This type is the placeholder for a hardware interrupt number. It has to
+ * be big enough to enclose whatever representation is used by a given
+ * platform.
+ */
+typedef unsigned long irq_hw_number_t;
+
 extern unsigned int nr_irq;
 
 #define NO_IRQ (-1)
@@ -21,7 +27,8 @@ extern unsigned int nr_irq;
 struct pt_regs;
 extern void do_IRQ(struct pt_regs *regs);
 
-/* irq_of_parse_and_map - Parse and Map an interrupt into linux virq space
+/**
+ * irq_of_parse_and_map - Parse and Map an interrupt into linux virq space
  * @device: Device node of the device whose interrupt is to be mapped
  * @index: Index of the interrupt to map
  *
@@ -40,4 +47,32 @@ static inline void irq_dispose_mapping(unsigned int virq)
 	return;
 }
 
+struct irq_host;
+
+/**
+ * irq_create_mapping - Map a hardware interrupt into linux virq space
+ * @host: host owning this hardware interrupt or NULL for default host
+ * @hwirq: hardware irq number in that host space
+ *
+ * Only one mapping per hardware interrupt is permitted. Returns a linux
+ * virq number.
+ * If the sense/trigger is to be specified, set_irq_type() should be called
+ * on the number returned from that call.
+ */
+extern unsigned int irq_create_mapping(struct irq_host *host,
+					irq_hw_number_t hwirq);
+
+/**
+ * irq_create_of_mapping - Map a hardware interrupt into linux virq space
+ * @controller: Device node of the interrupt controller
+ * @inspec: Interrupt specifier from the device-tree
+ * @intsize: Size of the interrupt specifier from the device-tree
+ *
+ * This function is identical to irq_create_mapping except that it takes
+ * as input informations straight from the device-tree (typically the results
+ * of the of_irq_map_*() functions.
+ */
+extern unsigned int irq_create_of_mapping(struct device_node *controller,
+					u32 *intspec, unsigned int intsize);
+
 #endif /* _ASM_MICROBLAZE_IRQ_H */

arch/microblaze/kernel/irq.c

@@ -93,3 +93,18 @@ skip:
 	}
 	return 0;
 }
+
+/* MS: There is no any advance mapping mechanism. We are using simple 32bit
+  intc without any cascades or any connection that's why mapping is 1:1 */
+unsigned int irq_create_mapping(struct irq_host *host, irq_hw_number_t hwirq)
+{
+	return hwirq;
+}
+EXPORT_SYMBOL_GPL(irq_create_mapping);
+
+unsigned int irq_create_of_mapping(struct device_node *controller,
+					u32 *intspec, unsigned int intsize)
+{
+	return intspec[0];
+}
+EXPORT_SYMBOL_GPL(irq_create_of_mapping);