[MIPS] Make irq number allocator generally available for fixing EV64120.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
index dd24434..9b0e49d 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.