[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, 5 insertions, 12 deletions

diff --git a/arch/mips/sgi-ip27/ip27-irq.c b/arch/mips/sgi-ip27/ip27-irq.c
index 270ecd3e6b4..824320281a3 100644
--- a/arch/mips/sgi-ip27/ip27-irq.c
+++ b/arch/mips/sgi-ip27/ip27-irq.c
@@ -332,11 +332,6 @@ static inline void disable_bridge_irq(unsigned int irq)
         intr_disconnect_level(cpu, swlevel);
 }
 
-static void mask_and_ack_bridge_irq(unsigned int irq)
-{
-        disable_bridge_irq(irq);
-}
-
 static void end_bridge_irq(unsigned int irq)
 {
         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)) &&
@@ -348,18 +343,16 @@ static struct irq_chip bridge_irq_type = {
         .typename       = "bridge",
         .startup        = startup_bridge_irq,
         .shutdown       = shutdown_bridge_irq,
-        .enable         = enable_bridge_irq,
-        .disable        = disable_bridge_irq,
-        .ack            = mask_and_ack_bridge_irq,
+        .ack            = disable_bridge_irq,
+        .mask           = disable_bridge_irq,
+        .mask_ack       = disable_bridge_irq,
+        .unmask         = enable_bridge_irq,
         .end            = end_bridge_irq,
 };
 
 void __devinit register_bridge_irq(unsigned int irq)
 {
-        irq_desc[irq].status    = IRQ_DISABLED;
-        irq_desc[irq].action    = 0;
-        irq_desc[irq].depth     = 1;
-        irq_desc[irq].chip      = &bridge_irq_type;
+        set_irq_chip(irq, &bridge_irq_type);
 }
 
 int __devinit request_bridge_irq(struct bridge_controller *bc)