[MIPS] Make irq number allocator generally available for fixing EV64120.

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

1 files changed, 42 insertions, 0 deletions

diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
index dd24434392b6..9b0e49d63d7b 100644
--- a/arch/mips/kernel/irq.c
+++ b/arch/mips/kernel/irq.c
@@ -26,6 +26,48 @@
 #include <asm/system.h>
 #include <asm/uaccess.h>
 
+static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];
+
+int __devinit allocate_irqno(void)
+{
+        int irq;
+
+again:
+        irq = find_first_zero_bit(irq_map, NR_IRQS);
+
+        if (irq >= NR_IRQS)
+                return -ENOSPC;
+
+        if (test_and_set_bit(irq, irq_map))
+                goto again;
+
+        return irq;
+}
+
+EXPORT_SYMBOL_GPL(allocate_irqno);
+
+/*
+ * Allocate the 16 legacy interrupts for i8259 devices.  This happens early
+ * in the kernel initialization so treating allocation failure as BUG() is
+ * ok.
+ */
+void __init alloc_legacy_irqno(void)
+{
+        int i;
+
+        for (i = 0; i <= 16; i++)
+                BUG_ON(test_and_set_bit(i, irq_map));
+}
+
+void __devinit free_irqno(unsigned int irq)
+{
+        smp_mb__before_clear_bit();
+        clear_bit(irq, irq_map);
+        smp_mb__after_clear_bit();
+}
+
+EXPORT_SYMBOL_GPL(free_irqno);
+
 /*
  * 'what should we do if we get a hw irq event on an illegal vector'.
  * each architecture has to answer this themselves.