[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>

1 files changed, 72 insertions, 6 deletions

diff --git a/arch/mips/sibyte/sb1250/irq.c b/arch/mips/sibyte/sb1250/irq.c
index 589537bfcc3d..0f6e54db4888 100644
--- a/arch/mips/sibyte/sb1250/irq.c
+++ b/arch/mips/sibyte/sb1250/irq.c
@@ -163,10 +163,6 @@ static void sb1250_set_affinity(unsigned int irq, cpumask_t mask)
 }
 #endif
 
-
-/* Defined in arch/mips/sibyte/sb1250/irq_handler.S */
-extern void sb1250_irq_handler(void);
-
 /*****************************************************************************/
 
 static unsigned int startup_sb1250_irq(unsigned int irq)
@@ -379,7 +375,6 @@ void __init arch_init_irq(void)
 #endif
         /* Enable necessary IPs, disable the rest */
         change_c0_status(ST0_IM, imask);
-        set_except_vector(0, sb1250_irq_handler);
 
 #ifdef CONFIG_KGDB
         if (kgdb_flag) {
@@ -409,7 +404,7 @@ void __init arch_init_irq(void)
 #define duart_out(reg, val)     csr_out32(val, IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
 #define duart_in(reg)           csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
 
-void sb1250_kgdb_interrupt(struct pt_regs *regs)
+static void sb1250_kgdb_interrupt(struct pt_regs *regs)
 {
         /*
          * Clear break-change status (allow some time for the remote
@@ -424,3 +419,74 @@ void sb1250_kgdb_interrupt(struct pt_regs *regs)
 }
 
 #endif  /* CONFIG_KGDB */
+
+static inline int dclz(unsigned long long x)
+{
+        int lz;
+
+        __asm__ (
+        "       .set    push                                            \n"
+        "       .set    mips64                                          \n"
+        "       dclz    %0, %1                                          \n"
+        "       .set    pop                                             \n"
+        : "=r" (lz)
+        : "r" (x));
+
+        return lz;
+}
+
+asmlinkage void plat_irq_dispatch(struct pt_regs *regs)
+{
+        unsigned int pending;
+
+#ifdef CONFIG_SIBYTE_SB1250_PROF
+        /* Set compare to count to silence count/compare timer interrupts */
+        write_c0_count(read_c0_count());
+#endif
+
+        /*
+         * What a pain. We have to be really careful saving the upper 32 bits
+         * of any * register across function calls if we don't want them
+         * trashed--since were running in -o32, the calling routing never saves
+         * the full 64 bits of a register across a function call.  Being the
+         * interrupt handler, we're guaranteed that interrupts are disabled
+         * during this code so we don't have to worry about random interrupts
+         * blasting the high 32 bits.
+         */
+
+        pending = read_c0_cause();
+
+#ifdef CONFIG_SIBYTE_SB1250_PROF
+        if (pending & CAUSEF_IP7) { /* Cpu performance counter interrupt */
+                sbprof_cpu_intr(exception_epc(regs));
+        }
+#endif
+
+        if (pending & CAUSEF_IP4)
+                sb1250_timer_interrupt(regs);
+
+#ifdef CONFIG_SMP
+        if (pending & CAUSEF_IP3)
+                sb1250_mailbox_interrupt(regs);
+#endif
+
+#ifdef CONFIG_KGDB
+        if (pending & CAUSEF_IP6)                       /* KGDB (uart 1) */
+                sb1250_kgdb_interrupt(regs);
+#endif
+
+        if (pending & CAUSEF_IP2) {
+                unsigned long long mask;
+
+                /*
+                 * Default...we've hit an IP[2] interrupt, which means we've
+                 * got to check the 1250 interrupt registers to figure out what
+                 * to do.  Need to detect which CPU we're on, now that
+                 ~ smp_affinity is supported.
+                 */
+                mask = __raw_readq(IOADDR(A_IMR_REGISTER(smp_processor_id(),
+                                              R_IMR_INTERRUPT_STATUS_BASE)));
+                if (mask)
+                        do_IRQ(63 - dclz(mask), regs);
+        }
+}