[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, 16 deletions

diff --git a/arch/mips/vr41xx/nec-cmbvr4133/irq.c b/arch/mips/vr41xx/nec-cmbvr4133/irq.c
index 2483487344c2..a039bb7251ff 100644
--- a/arch/mips/vr41xx/nec-cmbvr4133/irq.c
+++ b/arch/mips/vr41xx/nec-cmbvr4133/irq.c
@@ -30,17 +30,6 @@ extern void init_8259A(int hoge);
 
 extern int vr4133_rockhopper;
 
-static unsigned int startup_i8259_irq(unsigned int irq)
-{
-        enable_8259A_irq(irq - I8259_IRQ_BASE);
-        return 0;
-}
-
-static void shutdown_i8259_irq(unsigned int irq)
-{
-        disable_8259A_irq(irq - I8259_IRQ_BASE);
-}
-
 static void enable_i8259_irq(unsigned int irq)
 {
         enable_8259A_irq(irq - I8259_IRQ_BASE);
@@ -64,11 +53,10 @@ static void end_i8259_irq(unsigned int irq)
 
 static struct irq_chip i8259_irq_type = {
         .typename       = "XT-PIC",
-        .startup        = startup_i8259_irq,
-        .shutdown       = shutdown_i8259_irq,
-        .enable         = enable_i8259_irq,
-        .disable        = disable_i8259_irq,
         .ack            = ack_i8259_irq,
+        .mask           = disable_i8259_irq,
+        .mask_ack       = ack_i8259_irq,
+        .unmask         = enable_i8259_irq,
         .end            = end_i8259_irq,
 };
 
@@ -104,7 +92,7 @@ void __init rockhopper_init_irq(void)
         }
 
         for (i = I8259_IRQ_BASE; i <= I8259_IRQ_LAST; i++)
-                irq_desc[i].chip = &i8259_irq_type;
+                set_irq_chip(i, &i8259_irq_type);
 
         setup_irq(I8259_SLAVE_IRQ, &i8259_slave_cascade);