1 files changed, 93 insertions, 0 deletions
diff --git a/arch/mips/include/asm/i8259.h b/arch/mips/include/asm/i8259.h
new file mode 100644
index 000000000..a54b9649d
--- /dev/null
+++ b/arch/mips/include/asm/i8259.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *	include/asm-mips/i8259.h
+ *
+ *	i8259A interrupt definitions.
+ *
+ *	Copyright (C) 2003  Maciej W. Rozycki
+ *	Copyright (C) 2003  Ralf Baechle <ralf@linux-mips.org>
+ */
+#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 raw_spinlock_t i8259A_lock;
+
+extern void make_8259A_irq(unsigned int irq);
+
+extern void init_i8259_irqs(void);
+extern struct irq_domain *__init_i8259_irqs(struct device_node *node);
+
+/**
+ * i8159_set_poll() - Override the i8259 polling function
+ * @poll: pointer to platform-specific polling function
+ *
+ * Call this to override the generic i8259 polling function, which directly
+ * accesses i8259 registers, with a platform specific one which may be faster
+ * in cases where hardware provides a more optimal means of polling for an
+ * interrupt.
+ */
+extern void i8259_set_poll(int (*poll)(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;
+
+	raw_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;
+	}
+
+	raw_spin_unlock(&i8259A_lock);
+
+	return likely(irq >= 0) ? irq + I8259A_IRQ_BASE : irq;
+}
+
+#endif /* _ASM_I8259_H */