1/*
2 *	linux/arch/alpha/kernel/irq.c
3 *
4 *	Copyright (C) 1995 Linus Torvalds
5 *
6 * This file contains the code used by various IRQ handling routines:
7 * asking for different IRQ's should be done through these routines
8 * instead of just grabbing them. Thus setups with different IRQ numbers
9 * shouldn't result in any weird surprises, and installing new handlers
10 * should be easier.
11 */
12
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/errno.h>
16#include <linux/kernel_stat.h>
17#include <linux/signal.h>
18#include <linux/sched.h>
19#include <linux/ptrace.h>
20#include <linux/interrupt.h>
21#include <linux/slab.h>
22#include <linux/random.h>
23#include <linux/init.h>
24#include <linux/irq.h>
25#include <linux/proc_fs.h>
26#include <linux/seq_file.h>
27#include <linux/profile.h>
28#include <linux/bitops.h>
29
30#include <asm/system.h>
31#include <asm/io.h>
32#include <asm/uaccess.h>
33
34volatile unsigned long irq_err_count;
35
36void ack_bad_irq(unsigned int irq)
37{
38	irq_err_count++;
39	printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
40}
41
42#ifdef CONFIG_SMP
43static char irq_user_affinity[NR_IRQS];
44
45int
46select_smp_affinity(unsigned int irq)
47{
48	static int last_cpu;
49	int cpu = last_cpu + 1;
50
51	if (!irq_desc[irq].chip->set_affinity || irq_user_affinity[irq])
52		return 1;
53
54	while (!cpu_possible(cpu))
55		cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
56	last_cpu = cpu;
57
58	irq_desc[irq].affinity = cpumask_of_cpu(cpu);
59	irq_desc[irq].chip->set_affinity(irq, cpumask_of_cpu(cpu));
60	return 0;
61}
62#endif /* CONFIG_SMP */
63
64int
65show_interrupts(struct seq_file *p, void *v)
66{
67#ifdef CONFIG_SMP
68	int j;
69#endif
70	int irq = *(loff_t *) v;
71	struct irqaction * action;
72	unsigned long flags;
73
74#ifdef CONFIG_SMP
75	if (irq == 0) {
76		seq_puts(p, "           ");
77		for_each_online_cpu(j)
78			seq_printf(p, "CPU%d       ", j);
79		seq_putc(p, '\n');
80	}
81#endif
82
83	if (irq < ACTUAL_NR_IRQS) {
84		spin_lock_irqsave(&irq_desc[irq].lock, flags);
85		action = irq_desc[irq].action;
86		if (!action)
87			goto unlock;
88		seq_printf(p, "%3d: ", irq);
89#ifndef CONFIG_SMP
90		seq_printf(p, "%10u ", kstat_irqs(irq));
91#else
92		for_each_online_cpu(j)
93			seq_printf(p, "%10u ", kstat_cpu(j).irqs[irq]);
94#endif
95		seq_printf(p, " %14s", irq_desc[irq].chip->typename);
96		seq_printf(p, "  %c%s",
97			(action->flags & IRQF_DISABLED)?'+':' ',
98			action->name);
99
100		for (action=action->next; action; action = action->next) {
101			seq_printf(p, ", %c%s",
102				  (action->flags & IRQF_DISABLED)?'+':' ',
103				   action->name);
104		}
105
106		seq_putc(p, '\n');
107unlock:
108		spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
109	} else if (irq == ACTUAL_NR_IRQS) {
110#ifdef CONFIG_SMP
111		seq_puts(p, "IPI: ");
112		for_each_online_cpu(j)
113			seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
114		seq_putc(p, '\n');
115#endif
116		seq_printf(p, "ERR: %10lu\n", irq_err_count);
117	}
118	return 0;
119}
120
121/*
122 * handle_irq handles all normal device IRQ's (the special
123 * SMP cross-CPU interrupts have their own specific
124 * handlers).
125 */
126
127#define MAX_ILLEGAL_IRQS 16
128
129void
130handle_irq(int irq)
131{
132	/*
133	 * We ack quickly, we don't want the irq controller
134	 * thinking we're snobs just because some other CPU has
135	 * disabled global interrupts (we have already done the
136	 * INT_ACK cycles, it's too late to try to pretend to the
137	 * controller that we aren't taking the interrupt).
138	 *
139	 * 0 return value means that this irq is already being
140	 * handled by some other CPU. (or is disabled)
141	 */
142	static unsigned int illegal_count=0;
143
144	if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
145		irq_err_count++;
146		illegal_count++;
147		printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
148		       irq);
149		return;
150	}
151
152	irq_enter();
153	/*
154	 * __do_IRQ() must be called with IPL_MAX. Note that we do not
155	 * explicitly enable interrupts afterwards - some MILO PALcode
156	 * (namely LX164 one) seems to have severe problems with RTI
157	 * at IPL 0.
158	 */
159	local_irq_disable();
160	__do_IRQ(irq);
161	irq_exit();
162}
163