[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, 34 deletions

diff --git a/arch/mips/sni/irq.c b/arch/mips/sni/irq.c
index 48fb74a7aaec..8511bcc6d99d 100644
--- a/arch/mips/sni/irq.c
+++ b/arch/mips/sni/irq.c
@@ -11,44 +11,25 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
-#include <linux/spinlock.h>
 
 #include <asm/i8259.h>
 #include <asm/io.h>
 #include <asm/sni.h>
 
-DEFINE_SPINLOCK(pciasic_lock);
-
 static void enable_pciasic_irq(unsigned int irq)
 {
         unsigned int mask = 1 << (irq - PCIMT_IRQ_INT2);
-        unsigned long flags;
 
-        spin_lock_irqsave(&pciasic_lock, flags);
         *(volatile u8 *) PCIMT_IRQSEL |= mask;
-        spin_unlock_irqrestore(&pciasic_lock, flags);
-}
-
-static unsigned int startup_pciasic_irq(unsigned int irq)
-{
-        enable_pciasic_irq(irq);
-        return 0; /* never anything pending */
 }
 
-#define shutdown_pciasic_irq    disable_pciasic_irq
-
 void disable_pciasic_irq(unsigned int irq)
 {
         unsigned int mask = ~(1 << (irq - PCIMT_IRQ_INT2));
-        unsigned long flags;
 
-        spin_lock_irqsave(&pciasic_lock, flags);
         *(volatile u8 *) PCIMT_IRQSEL &= mask;
-        spin_unlock_irqrestore(&pciasic_lock, flags);
 }
 
-#define mask_and_ack_pciasic_irq disable_pciasic_irq
-
 static void end_pciasic_irq(unsigned int irq)
 {
         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
@@ -57,11 +38,10 @@ static void end_pciasic_irq(unsigned int irq)
 
 static struct irq_chip pciasic_irq_type = {
         .typename = "ASIC-PCI",
-        .startup = startup_pciasic_irq,
-        .shutdown = shutdown_pciasic_irq,
-        .enable = enable_pciasic_irq,
-        .disable = disable_pciasic_irq,
-        .ack = mask_and_ack_pciasic_irq,
+        .ack = disable_pciasic_irq,
+        .mask = disable_pciasic_irq,
+        .mask_ack = disable_pciasic_irq,
+        .unmask = enable_pciasic_irq,
         .end = end_pciasic_irq,
 };
 
@@ -178,12 +158,8 @@ asmlinkage void plat_irq_dispatch(void)
 
 void __init init_pciasic(void)
 {
-        unsigned long flags;
-
-        spin_lock_irqsave(&pciasic_lock, flags);
         * (volatile u8 *) PCIMT_IRQSEL =
                 IT_EISA | IT_INTA | IT_INTB | IT_INTC | IT_INTD;
-        spin_unlock_irqrestore(&pciasic_lock, flags);
 }
 
 /*
@@ -199,12 +175,8 @@ void __init arch_init_irq(void)
         init_pciasic();
 
         /* Actually we've got more interrupts to handle ...  */
-        for (i = PCIMT_IRQ_INT2; i <= PCIMT_IRQ_ETHERNET; i++) {
-                irq_desc[i].status     = IRQ_DISABLED;
-                irq_desc[i].action     = 0;
-                irq_desc[i].depth      = 1;
-                irq_desc[i].chip    = &pciasic_irq_type;
-        }
+        for (i = PCIMT_IRQ_INT2; i <= PCIMT_IRQ_ETHERNET; i++)
+                set_irq_chip(i, &pciasic_irq_type);
 
         change_c0_status(ST0_IM, IE_IRQ1|IE_IRQ2|IE_IRQ3|IE_IRQ4);
 }