[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, 4 insertions, 36 deletions

diff --git a/arch/mips/gt64120/ev64120/irq.c b/arch/mips/gt64120/ev64120/irq.c
index ed4d82b9a24a..b3e5796c81d7 100644
--- a/arch/mips/gt64120/ev64120/irq.c
+++ b/arch/mips/gt64120/ev64120/irq.c
@@ -66,38 +66,21 @@ asmlinkage void plat_irq_dispatch(void)
 
 static void disable_ev64120_irq(unsigned int irq_nr)
 {
-        unsigned long flags;
-
-        local_irq_save(flags);
         if (irq_nr >= 8) {      // All PCI interrupts are on line 5 or 2
                 clear_c0_status(9 << 10);
         } else {
                 clear_c0_status(1 << (irq_nr + 8));
         }
-        local_irq_restore(flags);
 }
 
 static void enable_ev64120_irq(unsigned int irq_nr)
 {
-        unsigned long flags;
-
-        local_irq_save(flags);
         if (irq_nr >= 8)        // All PCI interrupts are on line 5 or 2
                 set_c0_status(9 << 10);
         else
                 set_c0_status(1 << (irq_nr + 8));
-        local_irq_restore(flags);
-}
-
-static unsigned int startup_ev64120_irq(unsigned int irq)
-{
-        enable_ev64120_irq(irq);
-        return 0;               /* Never anything pending  */
 }
 
-#define shutdown_ev64120_irq     disable_ev64120_irq
-#define mask_and_ack_ev64120_irq disable_ev64120_irq
-
 static void end_ev64120_irq(unsigned int irq)
 {
         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
@@ -106,13 +89,11 @@ static void end_ev64120_irq(unsigned int irq)
 
 static struct irq_chip ev64120_irq_type = {
         .typename       = "EV64120",
-        .startup        = startup_ev64120_irq,
-        .shutdown       = shutdown_ev64120_irq,
-        .enable         = enable_ev64120_irq,
-        .disable        = disable_ev64120_irq,
-        .ack            = mask_and_ack_ev64120_irq,
+        .ack            = disable_ev64120_irq,
+        .mask           = disable_ev64120_irq,
+        .mask_ack       = disable_ev64120_irq,
+        .unmask         = enable_ev64120_irq,
         .end            = end_ev64120_irq,
-        .set_affinity   = NULL
 };
 
 void gt64120_irq_setup(void)
@@ -122,8 +103,6 @@ void gt64120_irq_setup(void)
          */
         clear_c0_status(ST0_IM);
 
-        local_irq_disable();
-
         /*
          * Enable timer.  Other interrupts will be enabled as they are
          * registered.
@@ -133,16 +112,5 @@ void gt64120_irq_setup(void)
 
 void __init arch_init_irq(void)
 {
-        int i;
-
-        /*  Let's initialize our IRQ descriptors  */
-        for (i = 0; i < NR_IRQS; i++) {
-                irq_desc[i].status = 0;
-                irq_desc[i].chip = &no_irq_chip;
-                irq_desc[i].action = NULL;
-                irq_desc[i].depth = 0;
-                spin_lock_init(&irq_desc[i].lock);
-        }
-
         gt64120_irq_setup();
 }