interrupt.c revision 0c3bd83b0974238a5808d342663c6407512564d0 
1/*
2 * Carsten Langgaard, carstenl@mips.com
3 * Copyright (C) 1999,2000 MIPS Technologies, Inc.  All rights reserved.
4 *
5 *  This program is free software; you can distribute it and/or modify it
6 *  under the terms of the GNU General Public License (Version 2) as
7 *  published by the Free Software Foundation.
8 *
9 *  This program is distributed in the hope it will be useful, but WITHOUT
10 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 *  for more details.
13 *
14 *  You should have received a copy of the GNU General Public License along
15 *  with this program; if not, write to the Free Software Foundation, Inc.,
16 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
17 *
18 * Routines for generic manipulation of the interrupts found on the
19 * Lasat boards.
20 */
21#include <linux/init.h>
22#include <linux/interrupt.h>
23#include <linux/irq.h>
24
25#include <asm/bootinfo.h>
26#include <asm/irq_cpu.h>
27#include <asm/lasat/lasatint.h>
28
29#include <irq.h>
30
31static volatile int *lasat_int_status;
32static volatile int *lasat_int_mask;
33static volatile int lasat_int_mask_shift;
34
35void disable_lasat_irq(unsigned int irq_nr)
36{
37	irq_nr -= LASAT_IRQ_BASE;
38	*lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
39}
40
41void enable_lasat_irq(unsigned int irq_nr)
42{
43	irq_nr -= LASAT_IRQ_BASE;
44	*lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
45}
46
47static struct irq_chip lasat_irq_type = {
48	.name = "Lasat",
49	.ack = disable_lasat_irq,
50	.mask = disable_lasat_irq,
51	.mask_ack = disable_lasat_irq,
52	.unmask = enable_lasat_irq,
53};
54
55static inline int ls1bit32(unsigned int x)
56{
57	int b = 31, s;
58
59	s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
60	s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
61	s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
62	s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
63	s =  1; if (x <<  1 == 0) s = 0; b -= s;
64
65	return b;
66}
67
68static unsigned long (*get_int_status)(void);
69
70static unsigned long get_int_status_100(void)
71{
72	return *lasat_int_status & *lasat_int_mask;
73}
74
75static unsigned long get_int_status_200(void)
76{
77	unsigned long int_status;
78
79	int_status = *lasat_int_status;
80	int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;
81	return int_status;
82}
83
84asmlinkage void plat_irq_dispatch(void)
85{
86	unsigned long int_status;
87	unsigned int cause = read_c0_cause();
88	int irq;
89
90	if (cause & CAUSEF_IP7) {	/* R4000 count / compare IRQ */
91		do_IRQ(7);
92		return;
93	}
94
95	int_status = get_int_status();
96
97	/* if int_status == 0, then the interrupt has already been cleared */
98	if (int_status) {
99		irq = LASAT_IRQ_BASE + ls1bit32(int_status);
100
101		do_IRQ(irq);
102	}
103}
104
105static struct irqaction cascade = {
106	.handler	= no_action,
107	.mask		= CPU_MASK_NONE,
108	.name		= "cascade",
109};
110
111void __init arch_init_irq(void)
112{
113	int i;
114
115	switch (mips_machtype) {
116	case MACH_LASAT_100:
117		lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
118		lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
119		lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
120		get_int_status = get_int_status_100;
121		*lasat_int_mask = 0;
122		break;
123	case MACH_LASAT_200:
124		lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
125		lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
126		lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
127		get_int_status = get_int_status_200;
128		*lasat_int_mask &= 0xffff;
129		break;
130	default:
131		panic("arch_init_irq: mips_machtype incorrect");
132	}
133
134	mips_cpu_irq_init();
135
136	for (i = LASAT_IRQ_BASE; i <= LASAT_IRQ_END; i++)
137		set_irq_chip_and_handler(i, &lasat_irq_type, handle_level_irq);
138
139	setup_irq(LASAT_CASCADE_IRQ, &cascade);
140}
141