xref: /openbmc/linux/arch/mips/kernel/irq.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Code to handle x86 style IRQs plus some generic interrupt stuff.
7  *
8  * Copyright (C) 1992 Linus Torvalds
9  * Copyright (C) 1994 - 2000 Ralf Baechle
10  */
11 #include <linux/kernel.h>
12 #include <linux/delay.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/kernel_stat.h>
16 #include <linux/module.h>
17 #include <linux/proc_fs.h>
18 #include <linux/slab.h>
19 #include <linux/mm.h>
20 #include <linux/random.h>
21 #include <linux/sched.h>
22 #include <linux/seq_file.h>
23 #include <linux/kallsyms.h>
24 
25 #include <asm/atomic.h>
26 #include <asm/system.h>
27 #include <asm/uaccess.h>
28 
29 static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];
30 
31 int allocate_irqno(void)
32 {
33 	int irq;
34 
35 again:
36 	irq = find_first_zero_bit(irq_map, NR_IRQS);
37 
38 	if (irq >= NR_IRQS)
39 		return -ENOSPC;
40 
41 	if (test_and_set_bit(irq, irq_map))
42 		goto again;
43 
44 	return irq;
45 }
46 
47 EXPORT_SYMBOL_GPL(allocate_irqno);
48 
49 /*
50  * Allocate the 16 legacy interrupts for i8259 devices.  This happens early
51  * in the kernel initialization so treating allocation failure as BUG() is
52  * ok.
53  */
54 void __init alloc_legacy_irqno(void)
55 {
56 	int i;
57 
58 	for (i = 0; i <= 16; i++)
59 		BUG_ON(test_and_set_bit(i, irq_map));
60 }
61 
62 void free_irqno(unsigned int irq)
63 {
64 	smp_mb__before_clear_bit();
65 	clear_bit(irq, irq_map);
66 	smp_mb__after_clear_bit();
67 }
68 
69 EXPORT_SYMBOL_GPL(free_irqno);
70 
71 /*
72  * 'what should we do if we get a hw irq event on an illegal vector'.
73  * each architecture has to answer this themselves.
74  */
75 void ack_bad_irq(unsigned int irq)
76 {
77 	printk("unexpected IRQ # %d\n", irq);
78 }
79 
80 atomic_t irq_err_count;
81 
82 #ifdef CONFIG_MIPS_MT_SMTC
83 /*
84  * SMTC Kernel needs to manipulate low-level CPU interrupt mask
85  * in do_IRQ. These are passed in setup_irq_smtc() and stored
86  * in this table.
87  */
88 unsigned long irq_hwmask[NR_IRQS];
89 #endif /* CONFIG_MIPS_MT_SMTC */
90 
91 /*
92  * Generic, controller-independent functions:
93  */
94 
95 int show_interrupts(struct seq_file *p, void *v)
96 {
97 	int i = *(loff_t *) v, j;
98 	struct irqaction * action;
99 	unsigned long flags;
100 
101 	if (i == 0) {
102 		seq_printf(p, "           ");
103 		for_each_online_cpu(j)
104 			seq_printf(p, "CPU%d       ",j);
105 		seq_putc(p, '\n');
106 	}
107 
108 	if (i < NR_IRQS) {
109 		spin_lock_irqsave(&irq_desc[i].lock, flags);
110 		action = irq_desc[i].action;
111 		if (!action)
112 			goto skip;
113 		seq_printf(p, "%3d: ",i);
114 #ifndef CONFIG_SMP
115 		seq_printf(p, "%10u ", kstat_irqs(i));
116 #else
117 		for_each_online_cpu(j)
118 			seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
119 #endif
120 		seq_printf(p, " %14s", irq_desc[i].chip->name);
121 		seq_printf(p, "  %s", action->name);
122 
123 		for (action=action->next; action; action = action->next)
124 			seq_printf(p, ", %s", action->name);
125 
126 		seq_putc(p, '\n');
127 skip:
128 		spin_unlock_irqrestore(&irq_desc[i].lock, flags);
129 	} else if (i == NR_IRQS) {
130 		seq_putc(p, '\n');
131 		seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
132 	}
133 	return 0;
134 }
135 
136 asmlinkage void spurious_interrupt(void)
137 {
138 	atomic_inc(&irq_err_count);
139 }
140 
141 #ifdef CONFIG_KGDB
142 extern void breakpoint(void);
143 extern void set_debug_traps(void);
144 
145 static int kgdb_flag = 1;
146 static int __init nokgdb(char *str)
147 {
148 	kgdb_flag = 0;
149 	return 1;
150 }
151 __setup("nokgdb", nokgdb);
152 #endif
153 
154 void __init init_IRQ(void)
155 {
156 	arch_init_irq();
157 
158 #ifdef CONFIG_KGDB
159 	if (kgdb_flag) {
160 		printk("Wait for gdb client connection ...\n");
161 		set_debug_traps();
162 		breakpoint();
163 	}
164 #endif
165 }
166