1 files changed, 86 insertions, 0 deletions

diff --git a/arch/mips/include/asm/i8259.h b/arch/mips/include/asm/i8259.h
new file mode 100644
index 000000000000..8572a2d90484
--- /dev/null
+++ b/arch/mips/include/asm/i8259.h
@@ -0,0 +1,86 @@
+/*
+ *      include/asm-mips/i8259.h
+ *
+ *      i8259A interrupt definitions.
+ *
+ *      Copyright (C) 2003  Maciej W. Rozycki
+ *      Copyright (C) 2003  Ralf Baechle <ralf@linux-mips.org>
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+#ifndef _ASM_I8259_H
+#define _ASM_I8259_H
+
+#include <linux/compiler.h>
+#include <linux/spinlock.h>
+
+#include <asm/io.h>
+#include <irq.h>
+
+/* i8259A PIC registers */
+#define PIC_MASTER_CMD          0x20
+#define PIC_MASTER_IMR          0x21
+#define PIC_MASTER_ISR          PIC_MASTER_CMD
+#define PIC_MASTER_POLL         PIC_MASTER_ISR
+#define PIC_MASTER_OCW3         PIC_MASTER_ISR
+#define PIC_SLAVE_CMD           0xa0
+#define PIC_SLAVE_IMR           0xa1
+
+/* i8259A PIC related value */
+#define PIC_CASCADE_IR          2
+#define MASTER_ICW4_DEFAULT     0x01
+#define SLAVE_ICW4_DEFAULT      0x01
+#define PIC_ICW4_AEOI           2
+
+extern spinlock_t i8259A_lock;
+
+extern int i8259A_irq_pending(unsigned int irq);
+extern void make_8259A_irq(unsigned int irq);
+
+extern void init_i8259_irqs(void);
+
+/*
+ * Do the traditional i8259 interrupt polling thing.  This is for the few
+ * cases where no better interrupt acknowledge method is available and we
+ * absolutely must touch the i8259.
+ */
+static inline int i8259_irq(void)
+{
+        int irq;
+
+        spin_lock(&i8259A_lock);
+
+        /* Perform an interrupt acknowledge cycle on controller 1. */
+        outb(0x0C, PIC_MASTER_CMD);             /* prepare for poll */
+        irq = inb(PIC_MASTER_CMD) & 7;
+        if (irq == PIC_CASCADE_IR) {
+                /*
+                 * Interrupt is cascaded so perform interrupt
+                 * acknowledge on controller 2.
+                 */
+                outb(0x0C, PIC_SLAVE_CMD);              /* prepare for poll */
+                irq = (inb(PIC_SLAVE_CMD) & 7) + 8;
+        }
+
+        if (unlikely(irq == 7)) {
+                /*
+                 * This may be a spurious interrupt.
+                 *
+                 * Read the interrupt status register (ISR). If the most
+                 * significant bit is not set then there is no valid
+                 * interrupt.
+                 */
+                outb(0x0B, PIC_MASTER_ISR);             /* ISR register */
+                if(~inb(PIC_MASTER_ISR) & 0x80)
+                        irq = -1;
+        }
+
+        spin_unlock(&i8259A_lock);
+
+        return likely(irq >= 0) ? irq + I8259A_IRQ_BASE : irq;
+}
+
+#endif /* _ASM_I8259_H */