[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, 22 deletions

diff --git a/arch/mips/mips-boards/atlas/atlas_int.c b/arch/mips/mips-boards/atlas/atlas_int.c
index be624b8c3b0e..7c710040d3f1 100644
--- a/arch/mips/mips-boards/atlas/atlas_int.c
+++ b/arch/mips/mips-boards/atlas/atlas_int.c
@@ -62,16 +62,6 @@ void enable_atlas_irq(unsigned int irq_nr)
         iob();
 }
 
-static unsigned int startup_atlas_irq(unsigned int irq)
-{
-        enable_atlas_irq(irq);
-        return 0; /* never anything pending */
-}
-
-#define shutdown_atlas_irq      disable_atlas_irq
-
-#define mask_and_ack_atlas_irq disable_atlas_irq
-
 static void end_atlas_irq(unsigned int irq)
 {
         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
@@ -80,11 +70,10 @@ static void end_atlas_irq(unsigned int irq)
 
 static struct irq_chip atlas_irq_type = {
         .typename = "Atlas",
-        .startup = startup_atlas_irq,
-        .shutdown = shutdown_atlas_irq,
-        .enable = enable_atlas_irq,
-        .disable = disable_atlas_irq,
-        .ack = mask_and_ack_atlas_irq,
+        .ack = disable_atlas_irq,
+        .mask = disable_atlas_irq,
+        .mask_ack = disable_atlas_irq,
+        .unmask = enable_atlas_irq,
         .end = end_atlas_irq,
 };
 
@@ -217,13 +206,8 @@ static inline void init_atlas_irqs (int base)
          */
         atlas_hw0_icregs->intrsten = 0xffffffff;
 
-        for (i = ATLAS_INT_BASE; i <= ATLAS_INT_END; i++) {
-                irq_desc[i].status      = IRQ_DISABLED;
-                irq_desc[i].action      = 0;
-                irq_desc[i].depth       = 1;
-                irq_desc[i].chip        = &atlas_irq_type;
-                spin_lock_init(&irq_desc[i].lock);
-        }
+        for (i = ATLAS_INT_BASE; i <= ATLAS_INT_END; i++)
+                set_irq_chip(i, &atlas_irq_type);
 }
 
 static struct irqaction atlasirq = {