sh: irq: Rework the SR.IMASK bitmap handling.

This tidies up how the SR.IMASK bitmap is managed, using the bitmap API
directly instead. At the same time, tidy up the irq_chip conversion a
bit.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/cpu/irq/imask.c

@@ -18,38 +18,17 @@
 #include <linux/spinlock.h>
 #include <linux/cache.h>
 #include <linux/irq.h>
+#include <linux/bitmap.h>
 #include <asm/system.h>
 #include <asm/irq.h>
 
 /* Bitmap of IRQ masked */
-static unsigned long imask_mask = 0x7fff;
-static int interrupt_priority = 0;
-
-static void enable_imask_irq(unsigned int irq);
-static void disable_imask_irq(unsigned int irq);
-static void shutdown_imask_irq(unsigned int irq);
-static void mask_and_ack_imask(unsigned int);
-static void end_imask_irq(unsigned int irq);
-
 #define IMASK_PRIORITY	15
 
-static unsigned int startup_imask_irq(unsigned int irq)
-{
-	/* Nothing to do */
-	return 0; /* never anything pending */
-}
+static DECLARE_BITMAP(imask_mask, IMASK_PRIORITY);
+static int interrupt_priority;
 
-static struct irq_chip imask_irq_type = {
-	.typename = "SR.IMASK",
-	.startup = startup_imask_irq,
-	.shutdown = shutdown_imask_irq,
-	.enable = enable_imask_irq,
-	.disable = disable_imask_irq,
-	.ack = mask_and_ack_imask,
-	.end = end_imask_irq
-};
-
-void static inline set_interrupt_registers(int ip)
+static inline void set_interrupt_registers(int ip)
 {
 	unsigned long __dummy;
 
@@ -72,42 +51,31 @@ void static inline set_interrupt_registers(int ip)
 		     : "t");
 }
 
-static void disable_imask_irq(unsigned int irq)
+static void mask_imask_irq(unsigned int irq)
 {
 	clear_bit(irq, &imask_mask);
 	if (interrupt_priority < IMASK_PRIORITY - irq)
 		interrupt_priority = IMASK_PRIORITY - irq;
-
 	set_interrupt_registers(interrupt_priority);
 }
 
-static void enable_imask_irq(unsigned int irq)
+static void unmask_imask_irq(unsigned int irq)
 {
 	set_bit(irq, &imask_mask);
-	interrupt_priority = IMASK_PRIORITY - ffz(imask_mask);
-
+	interrupt_priority = IMASK_PRIORITY -
+		find_first_zero_bit(imask_mask, IMASK_PRIORITY);
 	set_interrupt_registers(interrupt_priority);
 }
 
-static void mask_and_ack_imask(unsigned int irq)
-{
-	disable_imask_irq(irq);
-}
-
-static void end_imask_irq(unsigned int irq)
-{
-	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
-		enable_imask_irq(irq);
-}
-
-static void shutdown_imask_irq(unsigned int irq)
-{
-	/* Nothing to do */
-}
+static struct irq_chip imask_irq_chip = {
+	.typename	= "SR.IMASK",
+	.mask		= mask_imask_irq,
+	.unmask		= unmask_imask_irq,
+	.mask_ack	= mask_imask_irq,
+};
 
 void make_imask_irq(unsigned int irq)
 {
-	disable_irq_nosync(irq);
-	irq_desc[irq].chip = &imask_irq_type;
-	enable_irq(irq);
+	set_irq_chip_and_handler_name(irq, &imask_irq_chip,
+				      handle_level_irq, "level");
 }