[MIPS] IRQ cleanups

This is a big irq cleanup patch.

* Use set_irq_chip() to register irq_chip.
* Initialize .mask, .unmask, .mask_ack field.  Functions for these
  method are already exist in most case.
* Do not initialize .startup, .shutdown, .enable, .disable fields if
  default routines provided by irq_chip_set_defaults() were suitable.
* Remove redundant irq_desc initializations.
* Remove unnecessary local_irq_save/local_irq_restore, spin_lock.

With this cleanup, it would be easy to switch to slightly lightwait
irq flow handlers (handle_level_irq(), etc.) instead of __do_IRQ().

Though whole this patch is quite large, changes in each irq_chip are
not quite simple.  Please review and test on your platform.  Thanks.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 6 insertions, 24 deletions

diff --git a/arch/mips/sibyte/sb1250/irq.c b/arch/mips/sibyte/sb1250/irq.c
index d5d26770daf6..82ce7533053f 100644
--- a/arch/mips/sibyte/sb1250/irq.c
+++ b/arch/mips/sibyte/sb1250/irq.c
@@ -44,11 +44,9 @@
  */
 
 
-#define shutdown_sb1250_irq     disable_sb1250_irq
 static void end_sb1250_irq(unsigned int irq);
 static void enable_sb1250_irq(unsigned int irq);
 static void disable_sb1250_irq(unsigned int irq);
-static unsigned int startup_sb1250_irq(unsigned int irq);
 static void ack_sb1250_irq(unsigned int irq);
 #ifdef CONFIG_SMP
 static void sb1250_set_affinity(unsigned int irq, cpumask_t mask);
@@ -70,11 +68,10 @@ extern char sb1250_duart_present[];
 
 static struct irq_chip sb1250_irq_type = {
         .typename = "SB1250-IMR",
-        .startup = startup_sb1250_irq,
-        .shutdown = shutdown_sb1250_irq,
-        .enable = enable_sb1250_irq,
-        .disable = disable_sb1250_irq,
         .ack = ack_sb1250_irq,
+        .mask = disable_sb1250_irq,
+        .mask_ack = ack_sb1250_irq,
+        .unmask = enable_sb1250_irq,
         .end = end_sb1250_irq,
 #ifdef CONFIG_SMP
         .set_affinity = sb1250_set_affinity
@@ -163,14 +160,6 @@ static void sb1250_set_affinity(unsigned int irq, cpumask_t mask)
 
 /*****************************************************************************/
 
-static unsigned int startup_sb1250_irq(unsigned int irq)
-{
-        sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
-
-        return 0;               /* never anything pending */
-}
-
-
 static void disable_sb1250_irq(unsigned int irq)
 {
         sb1250_mask_irq(sb1250_irq_owner[irq], irq);
@@ -239,16 +228,9 @@ void __init init_sb1250_irqs(void)
 {
         int i;
 
-        for (i = 0; i < NR_IRQS; i++) {
-                irq_desc[i].status = IRQ_DISABLED;
-                irq_desc[i].action = 0;
-                irq_desc[i].depth = 1;
-                if (i < SB1250_NR_IRQS) {
-                        irq_desc[i].chip = &sb1250_irq_type;
-                        sb1250_irq_owner[i] = 0;
-                } else {
-                        irq_desc[i].chip = &no_irq_chip;
-                }
+        for (i = 0; i < SB1250_NR_IRQS; i++) {
+                set_irq_chip(i, &sb1250_irq_type);
+                sb1250_irq_owner[i] = 0;
         }
 }