patch-2.4.19 linux-2.4.19/arch/mips/kernel/irq_cpu.c

• Lines: 94
• Date: Fri Aug 2 17:39:43 2002
• Orig file: linux-2.4.18/arch/mips/kernel/irq_cpu.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.18/arch/mips/kernel/irq_cpu.c linux-2.4.19/arch/mips/kernel/irq_cpu.c
@@ -0,0 +1,93 @@
+/*
+ * Copyright 2001 MontaVista Software Inc.
+ * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
+ *
+ * This file define the irq handler for MIPS CPU interrupts.
+ *
+ * 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.
+ */
+
+/*
+ * Almost all MIPS CPUs define 8 interrupt sources.  They are typically
+ * level triggered (i.e., cannot be cleared from CPU; must be cleared from
+ * device).  The first two are software interrupts.  The last one is 
+ * usually the CPU timer interrupt if counter register is present or, for
+ * CPUs with an external FPU, by convention it's the FPU exception interrupt.
+ *
+ * This file exports one global function:
+ *	void mips_cpu_irq_init(int irq_base);
+ */
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+
+#include <asm/irq_cpu.h>
+#include <asm/mipsregs.h>
+
+static int mips_cpu_irq_base = -1;
+
+static void mips_cpu_irq_enable(unsigned int irq)
+{
+	clear_cp0_cause( 1 << (irq - mips_cpu_irq_base + 8));
+	set_cp0_status(1 << (irq - mips_cpu_irq_base + 8));
+}
+
+static void mips_cpu_irq_disable(unsigned int irq)
+{
+	clear_cp0_status(1 << (irq - mips_cpu_irq_base + 8));
+}
+
+static unsigned int mips_cpu_irq_startup(unsigned int irq)
+{
+	mips_cpu_irq_enable(irq);
+
+	return 0;
+}
+
+#define	mips_cpu_irq_shutdown	mips_cpu_irq_disable
+
+static void mips_cpu_irq_ack(unsigned int irq)
+{
+	/* although we attemp to clear the IP bit in cause reigster, I think
+	 * usually it is cleared by device (irq source)
+	 */
+	clear_cp0_cause(1 << (irq - mips_cpu_irq_base + 8));
+
+	/* disable this interrupt - so that we safe proceed to the handler */
+	mips_cpu_irq_disable(irq);
+}
+
+static void mips_cpu_irq_end(unsigned int irq)
+{
+	if(!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS)))
+		mips_cpu_irq_enable(irq);
+}
+
+static hw_irq_controller mips_cpu_irq_controller = {
+	"MIPS",
+	mips_cpu_irq_startup,
+	mips_cpu_irq_shutdown,
+	mips_cpu_irq_enable,
+	mips_cpu_irq_disable,
+	mips_cpu_irq_ack,
+	mips_cpu_irq_end,
+	NULL			/* no affinity stuff for UP */
+};
+
+
+void __init mips_cpu_irq_init(int irq_base)
+{
+	int i;
+
+	for (i = irq_base; i < irq_base + 8; i++) {
+		irq_desc[i].status = IRQ_DISABLED;
+		irq_desc[i].action = NULL;
+		irq_desc[i].depth = 1;
+		irq_desc[i].handler = &mips_cpu_irq_controller;
+	}
+
+	mips_cpu_irq_base = irq_base;
+}