x86, irq: Add data structure to keep AMD specific irq remapping information

Add a data structure to store information the IOMMU driver
can use to get from a 'struct irq_cfg' to the remapping
entry.
Signed-off-by: Joerg Roedel <joro@8bytes.org>
Acked-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/include/asm/hw_irq.h

@@ -101,6 +101,7 @@ static inline void set_io_apic_irq_attr(struct io_apic_irq_attr *irq_attr,
 	irq_attr->polarity	= polarity;
 }
 
+/* Intel specific interrupt remapping information */
 struct irq_2_iommu {
 	struct intel_iommu *iommu;
 	u16 irte_index;
@@ -108,6 +109,12 @@ struct irq_2_iommu {
 	u8  irte_mask;
 };
 
+/* AMD specific interrupt remapping information */
+struct irq_2_irte {
+	u16 devid; /* Device ID for IRTE table */
+	u16 index; /* Index into IRTE table*/
+};
+
 /*
  * This is performance-critical, we want to do it O(1)
  *
@@ -120,7 +127,10 @@ struct irq_cfg {
 	u8			vector;
 	u8			move_in_progress : 1;
 #ifdef CONFIG_IRQ_REMAP
-	struct irq_2_iommu	irq_2_iommu;
+	union {
+		struct irq_2_iommu irq_2_iommu;
+		struct irq_2_irte  irq_2_irte;
+	};
 #endif
 };