1/*
  2 * Copyright 2001 MontaVista Software Inc.
  3 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
  4 *
  5 * Copyright (C) 2001 Ralf Baechle
  6 * Copyright (C) 2005  MIPS Technologies, Inc.  All rights reserved.
  7 *      Author: Maciej W. Rozycki <macro@mips.com>
  8 *
  9 * This file define the irq handler for MIPS CPU interrupts.
 10 *
 11 * This program is free software; you can redistribute  it and/or modify it
 12 * under  the terms of  the GNU General  Public License as published by the
 13 * Free Software Foundation;  either version 2 of the  License, or (at your
 14 * option) any later version.
 15 */
 16
 17/*
 18 * Almost all MIPS CPUs define 8 interrupt sources.  They are typically
 19 * level triggered (i.e., cannot be cleared from CPU; must be cleared from
 20 * device).  The first two are software interrupts which we don't really
 21 * use or support.  The last one is usually the CPU timer interrupt if
 22 * counter register is present or, for CPUs with an external FPU, by
 23 * convention it's the FPU exception interrupt.
 24 *
 25 * Don't even think about using this on SMP.  You have been warned.
 26 *
 27 * This file exports one global function:
 28 *	void mips_cpu_irq_init(void);
 29 */
 30#include <linux/init.h>
 31#include <linux/interrupt.h>
 32#include <linux/kernel.h>
 33#include <linux/irq.h>
 34
 35#include <asm/irq_cpu.h>
 36#include <asm/mipsregs.h>
 37#include <asm/mipsmtregs.h>
 38#include <asm/system.h>
 39
 40static inline void unmask_mips_irq(struct irq_data *d)
 41{
 42	set_c0_status(0x100 << (d->irq - MIPS_CPU_IRQ_BASE));
 43	irq_enable_hazard();
 44}
 45
 46static inline void mask_mips_irq(struct irq_data *d)
 47{
 48	clear_c0_status(0x100 << (d->irq - MIPS_CPU_IRQ_BASE));
 49	irq_disable_hazard();
 50}
 51
 52static struct irq_chip mips_cpu_irq_controller = {
 53	.name		= "MIPS",
 54	.irq_ack	= mask_mips_irq,
 55	.irq_mask	= mask_mips_irq,
 56	.irq_mask_ack	= mask_mips_irq,
 57	.irq_unmask	= unmask_mips_irq,
 58	.irq_eoi	= unmask_mips_irq,
 59};
 60
 61/*
 62 * Basically the same as above but taking care of all the MT stuff
 63 */
 64
 65static unsigned int mips_mt_cpu_irq_startup(struct irq_data *d)
 66{
 67	unsigned int vpflags = dvpe();
 68
 69	clear_c0_cause(0x100 << (d->irq - MIPS_CPU_IRQ_BASE));
 70	evpe(vpflags);
 71	unmask_mips_irq(d);
 72	return 0;
 73}
 74
 75/*
 76 * While we ack the interrupt interrupts are disabled and thus we don't need
 77 * to deal with concurrency issues.  Same for mips_cpu_irq_end.
 78 */
 79static void mips_mt_cpu_irq_ack(struct irq_data *d)
 80{
 81	unsigned int vpflags = dvpe();
 82	clear_c0_cause(0x100 << (d->irq - MIPS_CPU_IRQ_BASE));
 83	evpe(vpflags);
 84	mask_mips_irq(d);
 85}
 86
 87static struct irq_chip mips_mt_cpu_irq_controller = {
 88	.name		= "MIPS",
 89	.irq_startup	= mips_mt_cpu_irq_startup,
 90	.irq_ack	= mips_mt_cpu_irq_ack,
 91	.irq_mask	= mask_mips_irq,
 92	.irq_mask_ack	= mips_mt_cpu_irq_ack,
 93	.irq_unmask	= unmask_mips_irq,
 94	.irq_eoi	= unmask_mips_irq,
 95};
 96
 97void __init mips_cpu_irq_init(void)
 98{
 99	int irq_base = MIPS_CPU_IRQ_BASE;
100	int i;
101
102	/* Mask interrupts. */
103	clear_c0_status(ST0_IM);
104	clear_c0_cause(CAUSEF_IP);
105
106	/* Software interrupts are used for MT/CMT IPI */
107	for (i = irq_base; i < irq_base + 2; i++)
108		irq_set_chip_and_handler(i, cpu_has_mipsmt ?
109					 &mips_mt_cpu_irq_controller :
110					 &mips_cpu_irq_controller,
111					 handle_percpu_irq);
112
113	for (i = irq_base + 2; i < irq_base + 8; i++)
114		irq_set_chip_and_handler(i, &mips_cpu_irq_controller,
115					 handle_percpu_irq);
116}