[MIPS] Rewrite all the assembler interrupt handlers to C.

Saves like 1,600 lines of code, is way easier to debug, compilers
frequently do a better job than the cut and paste type of handlers many
boards had.  And finally having all the stuff done in a single place
also means alot of bug potencial for the MT ASE is gone.

The only surviving handler in assembler is the DECstation one; I hope
Maciej will rewrite it.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

3 files changed, 54 insertions, 125 deletions

diff --git a/arch/mips/sgi-ip22/Makefile b/arch/mips/sgi-ip22/Makefile
index eb0820fe50b..6aa4c0cd169 100644
--- a/arch/mips/sgi-ip22/Makefile
+++ b/arch/mips/sgi-ip22/Makefile
@@ -3,7 +3,7 @@
 # under Linux.
 #
 
-obj-y	+= ip22-mc.o ip22-hpc.o ip22-int.o ip22-irq.o ip22-berr.o \
+obj-y	+= ip22-mc.o ip22-hpc.o ip22-int.o ip22-berr.o \
 	   ip22-time.o ip22-nvram.o ip22-reset.o ip22-setup.o
 
 obj-$(CONFIG_EISA)	+= ip22-eisa.o
diff --git a/arch/mips/sgi-ip22/ip22-int.c b/arch/mips/sgi-ip22/ip22-int.c
index d16fb43b1a9..fc6a7e2b189 100644
--- a/arch/mips/sgi-ip22/ip22-int.c
+++ b/arch/mips/sgi-ip22/ip22-int.c
@@ -37,7 +37,6 @@ static char lc1msk_to_irqnr[256];
 static char lc2msk_to_irqnr[256];
 static char lc3msk_to_irqnr[256];
 
-extern asmlinkage void indyIRQ(void);
 extern int ip22_eisa_init(void);
 
 static void enable_local0_irq(unsigned int irq)
@@ -224,7 +223,7 @@ static struct hw_interrupt_type ip22_local3_irq_type = {
 	.end		= end_local3_irq,
 };
 
-void indy_local0_irqdispatch(struct pt_regs *regs)
+static void indy_local0_irqdispatch(struct pt_regs *regs)
 {
 	u8 mask = sgint->istat0 & sgint->imask0;
 	u8 mask2;
@@ -242,7 +241,7 @@ void indy_local0_irqdispatch(struct pt_regs *regs)
 	return;
 }
 
-void indy_local1_irqdispatch(struct pt_regs *regs)
+static void indy_local1_irqdispatch(struct pt_regs *regs)
 {
 	u8 mask = sgint->istat1 & sgint->imask1;
 	u8 mask2;
@@ -262,7 +261,7 @@ void indy_local1_irqdispatch(struct pt_regs *regs)
 
 extern void ip22_be_interrupt(int irq, struct pt_regs *regs);
 
-void indy_buserror_irq(struct pt_regs *regs)
+static void indy_buserror_irq(struct pt_regs *regs)
 {
 	int irq = SGI_BUSERR_IRQ;
 
@@ -307,6 +306,56 @@ static struct irqaction map1_cascade = {
 #define SGI_INTERRUPTS	SGINT_LOCAL3
 #endif
 
+extern void indy_r4k_timer_interrupt(struct pt_regs *regs);
+extern void indy_8254timer_irq(struct pt_regs *regs);
+
+/*
+ * IRQs on the INDY look basically (barring software IRQs which we don't use
+ * at all) like:
+ *
+ *	MIPS IRQ	Source
+ *      --------        ------
+ *             0	Software (ignored)
+ *             1        Software (ignored)
+ *             2        Local IRQ level zero
+ *             3        Local IRQ level one
+ *             4        8254 Timer zero
+ *             5        8254 Timer one
+ *             6        Bus Error
+ *             7        R4k timer (what we use)
+ *
+ * We handle the IRQ according to _our_ priority which is:
+ *
+ * Highest ----     R4k Timer
+ *                  Local IRQ zero
+ *                  Local IRQ one
+ *                  Bus Error
+ *                  8254 Timer zero
+ * Lowest  ----     8254 Timer one
+ *
+ * then we just return, if multiple IRQs are pending then we will just take
+ * another exception, big deal.
+ */
+
+asmlinkage void plat_irq_dispatch(struct pt_regs *regs)
+{
+	unsigned int pending = read_c0_cause();
+
+	/*
+	 * First we check for r4k counter/timer IRQ.
+	 */
+	if (pending & CAUSEF_IP7)
+		indy_r4k_timer_interrupt(regs);
+	else if (pending & CAUSEF_IP2)
+		indy_local0_irqdispatch(regs);
+	else if (pending & CAUSEF_IP3)
+		indy_local1_irqdispatch(regs);
+	else if (pending & CAUSEF_IP6)
+		indy_buserror_irq(regs);
+	else if (pending & (CAUSEF_IP4 | CAUSEF_IP5))
+		indy_8254timer_irq(regs);
+}
+
 extern void mips_cpu_irq_init(unsigned int irq_base);
 
 void __init arch_init_irq(void)
@@ -369,8 +418,6 @@ void __init arch_init_irq(void)
 	sgint->cmeimask0 = 0;
 	sgint->cmeimask1 = 0;
 
-	set_except_vector(0, indyIRQ);
-
 	/* init CPU irqs */
 	mips_cpu_irq_init(SGINT_CPU);
 
diff --git a/arch/mips/sgi-ip22/ip22-irq.S b/arch/mips/sgi-ip22/ip22-irq.S
deleted file mode 100644
index 6ccbd9e1d96..00000000000
--- a/arch/mips/sgi-ip22/ip22-irq.S
+++ /dev/null
@@ -1,118 +0,0 @@
-/*
- * ip22-irq.S: Interrupt exception dispatch code for FullHouse and
- *             Guiness.
- *
- * Copyright (C) 1996 David S. Miller (dm@engr.sgi.com)
- */
-
-#include <asm/asm.h>
-#include <asm/mipsregs.h>
-#include <asm/regdef.h>
-#include <asm/stackframe.h>
-
-/* A lot of complication here is taken away because:
- *
- * 1) We handle one interrupt and return, sitting in a loop and moving across
- *    all the pending IRQ bits in the cause register is _NOT_ the answer, the
- *    common case is one pending IRQ so optimize in that direction.
- *
- * 2) We need not check against bits in the status register IRQ mask, that
- *    would make this routine slow as hell.
- *
- * 3) Linux only thinks in terms of all IRQs on or all IRQs off, nothing in
- *    between like BSD spl() brain-damage.
- *
- * Furthermore, the IRQs on the INDY look basically (barring software IRQs
- * which we don't use at all) like:
- *
- *	MIPS IRQ	Source
- *      --------        ------
- *             0	Software (ignored)
- *             1        Software (ignored)
- *             2        Local IRQ level zero
- *             3        Local IRQ level one
- *             4        8254 Timer zero
- *             5        8254 Timer one
- *             6        Bus Error
- *             7        R4k timer (what we use)
- *
- * We handle the IRQ according to _our_ priority which is:
- *
- * Highest ----     R4k Timer
- *                  Local IRQ zero
- *                  Local IRQ one
- *                  Bus Error
- *                  8254 Timer zero
- * Lowest  ----     8254 Timer one
- *
- * then we just return, if multiple IRQs are pending then we will just take
- * another exception, big deal.
- */
-
-	.text
-	.set	noreorder
-	.set	noat
-	.align	5
-	NESTED(indyIRQ, PT_SIZE, sp)
-	SAVE_ALL
-	CLI
-	.set	at
-	mfc0	s0, CP0_CAUSE		# get irq mask
-
-	/* First we check for r4k counter/timer IRQ. */
-	andi	a0, s0, CAUSEF_IP7
-	beq	a0, zero, 1f
-	 andi	a0, s0, CAUSEF_IP2	# delay slot, check local level zero
-
-	/* Wheee, a timer interrupt. */
-	jal	indy_r4k_timer_interrupt
-	 move	a0, sp			# delay slot
-	j	ret_from_irq
-	 nop				# delay slot
-
-1:
-	beq	a0, zero, 1f
-	 andi	a0, s0, CAUSEF_IP3	# delay slot, check local level one
-
-	/* Wheee, local level zero interrupt. */
-	jal	indy_local0_irqdispatch
-	 move	a0, sp			# delay slot
-
-	j	ret_from_irq
-	 nop				# delay slot
-
-1:
-	beq	a0, zero, 1f
-	 andi	a0, s0, CAUSEF_IP6	# delay slot, check bus error
-
-	/* Wheee, local level one interrupt. */
-	jal	indy_local1_irqdispatch
-	 move	a0, sp			# delay slot
-	j	ret_from_irq
-	 nop				# delay slot
-
-1:
-	beq	a0, zero, 1f
-	 andi	a0, s0, (CAUSEF_IP4 | CAUSEF_IP5)	# delay slot
-
-	/* Wheee, an asynchronous bus error... */
-	jal	indy_buserror_irq
-	 move	a0, sp			# delay slot
-	j	ret_from_irq
-	 nop				# delay slot
-
-1:
-	/* Here by mistake? It is possible, that by the time we take
-	 * the exception the IRQ pin goes low, so just leave if this
-	 * is the case.
-	 */
-	beq	a0, zero, 1f
-	 nop			  	# delay slot
-
-	/* Must be one of the 8254 timers... */
-	jal	indy_8254timer_irq
-	 move	a0, sp			# delay slot
-1:
-	j	ret_from_irq
-	 nop				# delay slot
-	END(indyIRQ)