[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 eb0820fe50bd..6aa4c0cd169c 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 d16fb43b1a93..fc6a7e2b189c 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 6ccbd9e1d967..000000000000
--- 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)