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/irq_cpu.h>
26 #include <asm/lasat/lasat.h>
27 #include <asm/lasat/lasatint.h>
28
29 #include <irq.h>
30
31 static volatile int *lasat_int_status;
32 static volatile int *lasat_int_mask;
33 static volatile int lasat_int_mask_shift;
34
disable_lasat_irq(struct irq_data * d)35 void disable_lasat_irq(struct irq_data *d)
36 {
37 unsigned int irq_nr = d->irq - LASAT_IRQ_BASE;
38
39 *lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
40 }
41
enable_lasat_irq(struct irq_data * d)42 void enable_lasat_irq(struct irq_data *d)
43 {
44 unsigned int irq_nr = d->irq - LASAT_IRQ_BASE;
45
46 *lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
47 }
48
49 static struct irq_chip lasat_irq_type = {
50 .name = "Lasat",
51 .irq_mask = disable_lasat_irq,
52 .irq_unmask = enable_lasat_irq,
53 };
54
ls1bit32(unsigned int x)55 static 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
68 static unsigned long (*get_int_status)(void);
69
get_int_status_100(void)70 static unsigned long get_int_status_100(void)
71 {
72 return *lasat_int_status & *lasat_int_mask;
73 }
74
get_int_status_200(void)75 static 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
plat_irq_dispatch(void)84 asmlinkage 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
105 static struct irqaction cascade = {
106 .handler = no_action,
107 .name = "cascade",
108 .flags = IRQF_NO_THREAD,
109 };
110
arch_init_irq(void)111 void __init arch_init_irq(void)
112 {
113 int i;
114
115 if (IS_LASAT_200()) {
116 lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
117 lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
118 lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
119 get_int_status = get_int_status_200;
120 *lasat_int_mask &= 0xffff;
121 } else {
122 lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
123 lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
124 lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
125 get_int_status = get_int_status_100;
126 *lasat_int_mask = 0;
127 }
128
129 mips_cpu_irq_init();
130
131 for (i = LASAT_IRQ_BASE; i <= LASAT_IRQ_END; i++)
132 irq_set_chip_and_handler(i, &lasat_irq_type, handle_level_irq);
133
134 setup_irq(LASAT_CASCADE_IRQ, &cascade);
135 }
136