[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, 47 deletions

diff --git a/arch/mips/kernel/irq-rm7000.c b/arch/mips/kernel/irq-rm7000.c
index 6b54c7109e2e..6a297e3b8899 100644
--- a/arch/mips/kernel/irq-rm7000.c
+++ b/arch/mips/kernel/irq-rm7000.c
@@ -29,42 +29,6 @@ static inline void mask_rm7k_irq(unsigned int irq)
         clear_c0_intcontrol(0x100 << (irq - irq_base));
 }
 
-static inline void rm7k_cpu_irq_enable(unsigned int irq)
-{
-        unsigned long flags;
-
-        local_irq_save(flags);
-        unmask_rm7k_irq(irq);
-        local_irq_restore(flags);
-}
-
-static void rm7k_cpu_irq_disable(unsigned int irq)
-{
-        unsigned long flags;
-
-        local_irq_save(flags);
-        mask_rm7k_irq(irq);
-        local_irq_restore(flags);
-}
-
-static unsigned int rm7k_cpu_irq_startup(unsigned int irq)
-{
-        rm7k_cpu_irq_enable(irq);
-
-        return 0;
-}
-
-#define rm7k_cpu_irq_shutdown   rm7k_cpu_irq_disable
-
-/*
- * While we ack the interrupt interrupts are disabled and thus we don't need
- * to deal with concurrency issues.  Same for rm7k_cpu_irq_end.
- */
-static void rm7k_cpu_irq_ack(unsigned int irq)
-{
-        mask_rm7k_irq(irq);
-}
-
 static void rm7k_cpu_irq_end(unsigned int irq)
 {
         if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS)))
@@ -73,11 +37,10 @@ static void rm7k_cpu_irq_end(unsigned int irq)
 
 static struct irq_chip rm7k_irq_controller = {
         .typename = "RM7000",
-        .startup = rm7k_cpu_irq_startup,
-        .shutdown = rm7k_cpu_irq_shutdown,
-        .enable = rm7k_cpu_irq_enable,
-        .disable = rm7k_cpu_irq_disable,
-        .ack = rm7k_cpu_irq_ack,
+        .ack = mask_rm7k_irq,
+        .mask = mask_rm7k_irq,
+        .mask_ack = mask_rm7k_irq,
+        .unmask = unmask_rm7k_irq,
         .end = rm7k_cpu_irq_end,
 };
 
@@ -87,12 +50,8 @@ void __init rm7k_cpu_irq_init(int base)
 
         clear_c0_intcontrol(0x00000f00);                /* Mask all */
 
-        for (i = base; i < base + 4; i++) {
-                irq_desc[i].status = IRQ_DISABLED;
-                irq_desc[i].action = NULL;
-                irq_desc[i].depth = 1;
-                irq_desc[i].chip = &rm7k_irq_controller;
-        }
+        for (i = base; i < base + 4; i++)
+                set_irq_chip(i, &rm7k_irq_controller);
 
         irq_base = base;
 }