[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, 30 deletions

diff --git a/arch/mips/lasat/interrupt.c b/arch/mips/lasat/interrupt.c
index a144a002dcc4..cac82afe5eb4 100644
--- a/arch/mips/lasat/interrupt.c
+++ b/arch/mips/lasat/interrupt.c
@@ -36,33 +36,14 @@ static volatile int lasat_int_mask_shift;
 
 void disable_lasat_irq(unsigned int irq_nr)
 {
-        unsigned long flags;
-
-        local_irq_save(flags);
         *lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
-        local_irq_restore(flags);
 }
 
 void enable_lasat_irq(unsigned int irq_nr)
 {
-        unsigned long flags;
-
-        local_irq_save(flags);
         *lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
-        local_irq_restore(flags);
 }
 
-static unsigned int startup_lasat_irq(unsigned int irq)
-{
-        enable_lasat_irq(irq);
-
-        return 0; /* never anything pending */
-}
-
-#define shutdown_lasat_irq      disable_lasat_irq
-
-#define mask_and_ack_lasat_irq disable_lasat_irq
-
 static void end_lasat_irq(unsigned int irq)
 {
         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
@@ -71,11 +52,10 @@ static void end_lasat_irq(unsigned int irq)
 
 static struct irq_chip lasat_irq_type = {
         .typename = "Lasat",
-        .startup = startup_lasat_irq,
-        .shutdown = shutdown_lasat_irq,
-        .enable = enable_lasat_irq,
-        .disable = disable_lasat_irq,
-        .ack = mask_and_ack_lasat_irq,
+        .ack = disable_lasat_irq,
+        .mask = disable_lasat_irq,
+        .mask_ack = disable_lasat_irq,
+        .unmask = enable_lasat_irq,
         .end = end_lasat_irq,
 };
 
@@ -152,10 +132,6 @@ void __init arch_init_irq(void)
                 panic("arch_init_irq: mips_machtype incorrect");
         }
 
-        for (i = 0; i <= LASATINT_END; i++) {
-                irq_desc[i].status      = IRQ_DISABLED;
-                irq_desc[i].action      = 0;
-                irq_desc[i].depth       = 1;
-                irq_desc[i].chip        = &lasat_irq_type;
-        }
+        for (i = 0; i <= LASATINT_END; i++)
+                set_irq_chip(i, &lasat_irq_type);
 }