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

[firefly-linux-kernel-4.4.55.git] / arch / mips / mips-boards / malta / malta_int.c

diff --git a/arch/mips/mips-boards/malta/malta_int.c b/arch/mips/mips-boards/malta/malta_int.c
index d06dc5ad6c9e55edd2284540ea01e729f2678d55..1da8c18b9c8e8c397907372f5f06b4fe8f597f0f 100644 (file)
--- a/arch/mips/mips-boards/malta/malta_int.c
+++ b/arch/mips/mips-boards/malta/malta_int.c
@@ -40,7 +40,6 @@
 #include <asm/mips-boards/msc01_pci.h>
 #include <asm/msc01_ic.h>
 
-extern asmlinkage void mipsIRQ(void);
 extern void mips_timer_interrupt(void);
 
 static DEFINE_SPINLOCK(mips_irq_lock);
@@ -114,7 +113,7 @@ static inline int get_int(void)
        return irq;
 }
 
-void malta_hw0_irqdispatch(struct pt_regs *regs)
+static void malta_hw0_irqdispatch(struct pt_regs *regs)
 {
        int irq;
 
@@ -182,6 +181,92 @@ void corehi_irqdispatch(struct pt_regs *regs)
         die("CoreHi interrupt", regs);
 }
 
+static inline int clz(unsigned long x)
+{
+       __asm__ (
+       "       .set    push                                    \n"
+       "       .set    mips32                                  \n"
+       "       clz     %0, %1                                  \n"
+       "       .set    pop                                     \n"
+       : "=r" (x)
+       : "r" (x));
+
+       return x;
+}
+
+/*
+ * Version of ffs that only looks at bits 12..15.
+ */
+static inline unsigned int irq_ffs(unsigned int pending)
+{
+#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
+       return -clz(pending) + 31 - CAUSEB_IP;
+#else
+       unsigned int a0 = 7;
+       unsigned int t0;
+
+       t0 = s0 & 0xf000;
+       t0 = t0 < 1;
+       t0 = t0 << 2;
+       a0 = a0 - t0;
+       s0 = s0 << t0;
+
+       t0 = s0 & 0xc000;
+       t0 = t0 < 1;
+       t0 = t0 << 1;
+       a0 = a0 - t0;
+       s0 = s0 << t0;
+
+       t0 = s0 & 0x8000;
+       t0 = t0 < 1;
+       //t0 = t0 << 2;
+       a0 = a0 - t0;
+       //s0 = s0 << t0;
+
+       return a0;
+#endif
+}
+
+/*
+ * IRQs on the Malta board look basically (barring software IRQs which we
+ * don't use at all and all external interrupt sources are combined together
+ * on hardware interrupt 0 (MIPS IRQ 2)) like:
+ *
+ *     MIPS IRQ        Source
+ *      --------        ------
+ *             0       Software (ignored)
+ *             1        Software (ignored)
+ *             2        Combined hardware interrupt (hw0)
+ *             3        Hardware (ignored)
+ *             4        Hardware (ignored)
+ *             5        Hardware (ignored)
+ *             6        Hardware (ignored)
+ *             7        R4k timer (what we use)
+ *
+ * We handle the IRQ according to _our_ priority which is:
+ *
+ * Highest ----     R4k Timer
+ * Lowest  ----     Combined hardware interrupt
+ *
+ * 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() & read_c0_status() & ST0_IM;
+       int irq;
+
+       irq = irq_ffs(pending);
+
+       if (irq == MIPSCPU_INT_I8259A)
+               malta_hw0_irqdispatch(regs);
+       else if (irq > 0)
+               do_IRQ(MIPSCPU_INT_BASE + irq, regs);
+       else
+               spurious_interrupt(regs);
+}
+
 static struct irqaction i8259irq = {
        .handler = no_action,
        .name = "XT-PIC cascade"
@@ -214,7 +299,6 @@ int __initdata msc_nr_eicirqs = sizeof(msc_eicirqmap)/sizeof(msc_irqmap_t);
 
 void __init arch_init_irq(void)
 {
-       set_except_vector(0, mipsIRQ);
        init_i8259_irqs();
 
        if (!cpu_has_veic)
@@ -245,7 +329,6 @@ void __init arch_init_irq(void)
                setup_irq (MIPSCPU_INT_BASE+MIPSCPU_INT_COREHI, &corehi_irqaction);
        }
        else {
-               set_except_vector(0, mipsIRQ);
                setup_irq (MIPSCPU_INT_BASE+MIPSCPU_INT_I8259A, &i8259irq);
                setup_irq (MIPSCPU_INT_BASE+MIPSCPU_INT_COREHI, &corehi_irqaction);
        }