diff --git a/arch/arm/plat-s3c64xx/include/plat/irqs.h b/arch/arm/plat-s3c64xx/include/plat/irqs.h
index 5ab41ad..bc25689 100644
--- a/arch/arm/plat-s3c64xx/include/plat/irqs.h
+++ b/arch/arm/plat-s3c64xx/include/plat/irqs.h
@@ -153,10 +153,44 @@
 #define S3C_EINT(x)		((x) + S3C_IRQ_EINT_BASE)
 #define IRQ_EINT(x)		S3C_EINT(x)
 
-/* Define NR_IRQs here, machine specific can always re-define.
- * Currently the IRQ_EINT27 is the last one we can have. */
+/* Next the external interrupt groups. These are similar to the IRQ_EINT(x)
+ * that they are sourced from the GPIO pins but with a different scheme for
+ * priority and source indication.
+ *
+ * The IRQ_EINT(x) can be thought of as 'group 0' of the available GPIO
+ * interrupts, but for historical reasons they are kept apart from these
+ * next interrupts.
+ *
+ * Use IRQ_EINT_GROUP(group, offset) to get the number for use in the
+ * machine specific support files.
+ */
 
-#define NR_IRQS	(S3C_EINT(27) + 1)
+#define IRQ_EINT_GROUP1_NR	(15)
+#define IRQ_EINT_GROUP2_NR	(8)
+#define IRQ_EINT_GROUP3_NR	(5)
+#define IRQ_EINT_GROUP4_NR	(14)
+#define IRQ_EINT_GROUP5_NR	(7)
+#define IRQ_EINT_GROUP6_NR	(10)
+#define IRQ_EINT_GROUP7_NR	(16)
+#define IRQ_EINT_GROUP8_NR	(15)
+#define IRQ_EINT_GROUP9_NR	(9)
+
+#define IRQ_EINT_GROUP_BASE	S3C_EINT(28)
+#define IRQ_EINT_GROUP1_BASE	(IRQ_EINT_GROUP_BASE + 0x00)
+#define IRQ_EINT_GROUP2_BASE	(IRQ_EINT_GROUP1_BASE + IRQ_EINT_GROUP1_NR)
+#define IRQ_EINT_GROUP3_BASE	(IRQ_EINT_GROUP2_BASE + IRQ_EINT_GROUP2_NR)
+#define IRQ_EINT_GROUP4_BASE	(IRQ_EINT_GROUP3_BASE + IRQ_EINT_GROUP3_NR)
+#define IRQ_EINT_GROUP5_BASE	(IRQ_EINT_GROUP4_BASE + IRQ_EINT_GROUP4_NR)
+#define IRQ_EINT_GROUP6_BASE	(IRQ_EINT_GROUP5_BASE + IRQ_EINT_GROUP5_NR)
+#define IRQ_EINT_GROUP7_BASE	(IRQ_EINT_GROUP6_BASE + IRQ_EINT_GROUP6_NR)
+#define IRQ_EINT_GROUP8_BASE	(IRQ_EINT_GROUP7_BASE + IRQ_EINT_GROUP7_NR)
+#define IRQ_EINT_GROUP9_BASE	(IRQ_EINT_GROUP8_BASE + IRQ_EINT_GROUP8_NR)
+
+#define IRQ_EINT_GROUP(group, no)	(IRQ_EINT_GROUP##group##__BASE + (x))
+
+/* Set the default NR_IRQS */
+
+#define NR_IRQS	(IRQ_EINT_GROUP9_BASE + IRQ_EINT_GROUP9_NR + 1)
 
 #endif /* __ASM_PLAT_S3C64XX_IRQS_H */