Merge branch 'for_paulus' of master.kernel.org:/pub/scm/linux/kernel/git/galak/powerpc

[pandora-kernel.git] / arch / mips / mips-boards / atlas / atlas_int.c

diff --git a/arch/mips/mips-boards/atlas/atlas_int.c b/arch/mips/mips-boards/atlas/atlas_int.c
index bc0ebc6..db53950 100644 (file)
--- a/arch/mips/mips-boards/atlas/atlas_int.c
+++ b/arch/mips/mips-boards/atlas/atlas_int.c
@@ -39,8 +39,6 @@
 
 static struct atlas_ictrl_regs *atlas_hw0_icregs;
 
-extern asmlinkage void mipsIRQ(void);
-
 #if 0
 #define DEBUG_INT(x...) printk(x)
 #else
@@ -98,7 +96,7 @@ static inline int ls1bit32(unsigned int x)
        return b;
 }
 
-void atlas_hw0_irqdispatch(struct pt_regs *regs)
+static inline void atlas_hw0_irqdispatch(struct pt_regs *regs)
 {
        unsigned long int_status;
        int irq;
@@ -116,6 +114,91 @@ void atlas_hw0_irqdispatch(struct pt_regs *regs)
        do_IRQ(irq, 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 Atlas 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_ATLAS)
+               atlas_hw0_irqdispatch(regs);
+       else if (irq > 0)
+               do_IRQ(MIPSCPU_INT_BASE + irq, regs);
+       else
+               spurious_interrupt(regs);
+}
+
 void __init arch_init_irq(void)
 {
        int i;
@@ -128,9 +211,6 @@ void __init arch_init_irq(void)
         */
        atlas_hw0_icregs->intrsten = 0xffffffff;
 
-       /* Now safe to set the exception vector. */
-       set_except_vector(0, mipsIRQ);
-
        for (i = ATLASINT_BASE; i <= ATLASINT_END; i++) {
                irq_desc[i].status      = IRQ_DISABLED;
                irq_desc[i].action      = 0;