interrupt.c revision a5ccfe5c1a48bff1e47788d470ee50974f7dd33d 
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/irq.h>
23#include <linux/sched.h>
24#include <linux/slab.h>
25#include <linux/interrupt.h>
26#include <linux/kernel_stat.h>
27
28#include <asm/bootinfo.h>
29#include <asm/irq_cpu.h>
30#include <asm/lasat/lasatint.h>
31#include <asm/time.h>
32#include <asm/gdb-stub.h>
33
34static volatile int *lasat_int_status;
35static volatile int *lasat_int_mask;
36static volatile int lasat_int_mask_shift;
37
38void disable_lasat_irq(unsigned int irq_nr)
39{
40	*lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
41}
42
43void enable_lasat_irq(unsigned int irq_nr)
44{
45	*lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
46}
47
48static struct irq_chip lasat_irq_type = {
49	.name = "Lasat",
50	.ack = disable_lasat_irq,
51	.mask = disable_lasat_irq,
52	.mask_ack = disable_lasat_irq,
53	.unmask = enable_lasat_irq,
54};
55
56static inline int ls1bit32(unsigned int x)
57{
58	int b = 31, s;
59
60	s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
61	s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
62	s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
63	s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
64	s =  1; if (x <<  1 == 0) s = 0; b -= s;
65
66	return b;
67}
68
69static unsigned long (*get_int_status)(void);
70
71static unsigned long get_int_status_100(void)
72{
73	return *lasat_int_status & *lasat_int_mask;
74}
75
76static unsigned long get_int_status_200(void)
77{
78	unsigned long int_status;
79
80	int_status = *lasat_int_status;
81	int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;
82	return int_status;
83}
84
85asmlinkage void plat_irq_dispatch(void)
86{
87	unsigned long int_status;
88	unsigned int cause = read_c0_cause();
89	int irq;
90
91	if (cause & CAUSEF_IP7) {	/* R4000 count / compare IRQ */
92		do_IRQ(7);
93		return;
94	}
95
96	int_status = get_int_status();
97
98	/* if int_status == 0, then the interrupt has already been cleared */
99	if (int_status) {
100		irq = LASATINT_BASE + ls1bit32(int_status);
101
102		do_IRQ(irq);
103	}
104}
105
106void __init arch_init_irq(void)
107{
108	int i;
109
110	switch (mips_machtype) {
111	case MACH_LASAT_100:
112		lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
113		lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
114		lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
115		get_int_status = get_int_status_100;
116		*lasat_int_mask = 0;
117		break;
118	case MACH_LASAT_200:
119		lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
120		lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
121		lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
122		get_int_status = get_int_status_200;
123		*lasat_int_mask &= 0xffff;
124		break;
125	default:
126		panic("arch_init_irq: mips_machtype incorrect");
127	}
128
129	mips_cpu_irq_init();
130	for (i = LASATINT_BASE; i <= LASATINT_END; i++)
131		set_irq_chip_and_handler(i, &lasat_irq_type, handle_level_irq);
132}
133