diff --git a/arch/mips/dec/ioasic-irq.c b/arch/mips/dec/ioasic-irq.c
index 41cd2a9..d0af08b 100644
--- a/arch/mips/dec/ioasic-irq.c
+++ b/arch/mips/dec/ioasic-irq.c
@@ -13,7 +13,6 @@
 
 #include <linux/init.h>
 #include <linux/irq.h>
-#include <linux/spinlock.h>
 #include <linux/types.h>
 
 #include <asm/dec/ioasic.h>
@@ -21,8 +20,6 @@
 #include <asm/dec/ioasic_ints.h>
 
 
-static DEFINE_SPINLOCK(ioasic_lock);
-
 static int ioasic_irq_base;
 
 
@@ -52,65 +49,31 @@
 	ioasic_write(IO_REG_SIR, sir);
 }
 
-static inline void enable_ioasic_irq(unsigned int irq)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&ioasic_lock, flags);
-	unmask_ioasic_irq(irq);
-	spin_unlock_irqrestore(&ioasic_lock, flags);
-}
-
-static inline void disable_ioasic_irq(unsigned int irq)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&ioasic_lock, flags);
-	mask_ioasic_irq(irq);
-	spin_unlock_irqrestore(&ioasic_lock, flags);
-}
-
-
-static inline unsigned int startup_ioasic_irq(unsigned int irq)
-{
-	enable_ioasic_irq(irq);
-	return 0;
-}
-
-#define shutdown_ioasic_irq disable_ioasic_irq
-
 static inline void ack_ioasic_irq(unsigned int irq)
 {
-	spin_lock(&ioasic_lock);
 	mask_ioasic_irq(irq);
-	spin_unlock(&ioasic_lock);
 	fast_iob();
 }
 
 static inline void end_ioasic_irq(unsigned int irq)
 {
 	if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS)))
-		enable_ioasic_irq(irq);
+		unmask_ioasic_irq(irq);
 }
 
 static struct irq_chip ioasic_irq_type = {
 	.typename = "IO-ASIC",
-	.startup = startup_ioasic_irq,
-	.shutdown = shutdown_ioasic_irq,
-	.enable = enable_ioasic_irq,
-	.disable = disable_ioasic_irq,
 	.ack = ack_ioasic_irq,
+	.mask = mask_ioasic_irq,
+	.mask_ack = ack_ioasic_irq,
+	.unmask = unmask_ioasic_irq,
 	.end = end_ioasic_irq,
 };
 
 
-#define startup_ioasic_dma_irq startup_ioasic_irq
+#define unmask_ioasic_dma_irq unmask_ioasic_irq
 
-#define shutdown_ioasic_dma_irq shutdown_ioasic_irq
-
-#define enable_ioasic_dma_irq enable_ioasic_irq
-
-#define disable_ioasic_dma_irq disable_ioasic_irq
+#define mask_ioasic_dma_irq mask_ioasic_irq
 
 #define ack_ioasic_dma_irq ack_ioasic_irq
 
@@ -123,11 +86,10 @@
 
 static struct irq_chip ioasic_dma_irq_type = {
 	.typename = "IO-ASIC-DMA",
-	.startup = startup_ioasic_dma_irq,
-	.shutdown = shutdown_ioasic_dma_irq,
-	.enable = enable_ioasic_dma_irq,
-	.disable = disable_ioasic_dma_irq,
 	.ack = ack_ioasic_dma_irq,
+	.mask = mask_ioasic_dma_irq,
+	.mask_ack = ack_ioasic_dma_irq,
+	.unmask = unmask_ioasic_dma_irq,
 	.end = end_ioasic_dma_irq,
 };
 
@@ -140,18 +102,10 @@
 	ioasic_write(IO_REG_SIMR, 0);
 	fast_iob();
 
-	for (i = base; i < base + IO_INR_DMA; i++) {
-		irq_desc[i].status = IRQ_DISABLED;
-		irq_desc[i].action = 0;
-		irq_desc[i].depth = 1;
-		irq_desc[i].chip = &ioasic_irq_type;
-	}
-	for (; i < base + IO_IRQ_LINES; i++) {
-		irq_desc[i].status = IRQ_DISABLED;
-		irq_desc[i].action = 0;
-		irq_desc[i].depth = 1;
-		irq_desc[i].chip = &ioasic_dma_irq_type;
-	}
+	for (i = base; i < base + IO_INR_DMA; i++)
+		set_irq_chip(i, &ioasic_irq_type);
+	for (; i < base + IO_IRQ_LINES; i++)
+		set_irq_chip(i, &ioasic_dma_irq_type);
 
 	ioasic_irq_base = base;
 }