[ARM] pxa: generalize the muxed gpio IRQ handling code with loop and ffs()

1. As David Brownell suggests, using ffs() is going to make the loop
   a bit faster (by avoiding unnecessary shift and iteration)

2. Russell suggested find_{first,next}_bit() being used with the
   gedr[] array

Signed-off-by: eric miao <eric.miao@marvell.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 16 insertions, 58 deletions

diff --git a/arch/arm/mach-pxa/irq.c b/arch/arm/mach-pxa/irq.c
index 36c6a68beca2..381fde66aeeb 100644
--- a/arch/arm/mach-pxa/irq.c
+++ b/arch/arm/mach-pxa/irq.c
@@ -178,73 +178,31 @@ static struct irq_chip pxa_low_gpio_chip = {
  * Demux handler for GPIO>=2 edge detect interrupts
  */
 
+#define GEDR_BITS       (sizeof(gedr) * BITS_PER_BYTE)
+
 static void pxa_gpio_demux_handler(unsigned int irq, struct irq_desc *desc)
 {
-        unsigned int mask;
-        int loop;
+        int loop, bit, n;
+        unsigned long gedr[4];
 
         do {
-                loop = 0;
+                gedr[0] = GEDR0 & GPIO_IRQ_mask[0] & ~3;
+                gedr[1] = GEDR1 & GPIO_IRQ_mask[1];
+                gedr[2] = GEDR2 & GPIO_IRQ_mask[2];
+                gedr[3] = GEDR3 & GPIO_IRQ_mask[3];
 
-                mask = GEDR0 & GPIO_IRQ_mask[0] & ~3;
-                if (mask) {
-                        GEDR0 = mask;
-                        irq = IRQ_GPIO(2);
-                        desc = irq_desc + irq;
-                        mask >>= 2;
-                        do {
-                                if (mask & 1)
-                                        desc_handle_irq(irq, desc);
-                                irq++;
-                                desc++;
-                                mask >>= 1;
-                        } while (mask);
-                        loop = 1;
-                }
+                GEDR0 = gedr[0]; GEDR1 = gedr[1];
+                GEDR2 = gedr[2]; GEDR3 = gedr[3];
 
-                mask = GEDR1 & GPIO_IRQ_mask[1];
-                if (mask) {
-                        GEDR1 = mask;
-                        irq = IRQ_GPIO(32);
-                        desc = irq_desc + irq;
-                        do {
-                                if (mask & 1)
-                                        desc_handle_irq(irq, desc);
-                                irq++;
-                                desc++;
-                                mask >>= 1;
-                        } while (mask);
+                loop = 0;
+                bit = find_first_bit(gedr, GEDR_BITS);
+                while (bit < GEDR_BITS) {
                         loop = 1;
-                }
 
-                mask = GEDR2 & GPIO_IRQ_mask[2];
-                if (mask) {
-                        GEDR2 = mask;
-                        irq = IRQ_GPIO(64);
-                        desc = irq_desc + irq;
-                        do {
-                                if (mask & 1)
-                                        desc_handle_irq(irq, desc);
-                                irq++;
-                                desc++;
-                                mask >>= 1;
-                        } while (mask);
-                        loop = 1;
-                }
+                        n = PXA_GPIO_IRQ_BASE + bit;
+                        desc_handle_irq(n, irq_desc + n);
 
-                mask = GEDR3 & GPIO_IRQ_mask[3];
-                if (mask) {
-                        GEDR3 = mask;
-                        irq = IRQ_GPIO(96);
-                        desc = irq_desc + irq;
-                        do {
-                                if (mask & 1)
-                                        desc_handle_irq(irq, desc);
-                                irq++;
-                                desc++;
-                                mask >>= 1;
-                        } while (mask);
-                        loop = 1;
+                        bit = find_next_bit(gedr, GEDR_BITS, bit + 1);
                 }
         } while (loop);
 }