7f912ba3d9ad79ee9f333f14dfcd0f3dc7bb59c5
[sfrench/cifs-2.6.git] / arch / alpha / kernel / irq.c
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/random.h>
22 #include <linux/init.h>
23 #include <linux/irq.h>
24 #include <linux/proc_fs.h>
25 #include <linux/seq_file.h>
26 #include <linux/profile.h>
27 #include <linux/bitops.h>
28
29 #include <asm/system.h>
30 #include <asm/io.h>
31 #include <asm/uaccess.h>
32
33 volatile unsigned long irq_err_count;
34
35 void ack_bad_irq(unsigned int irq)
36 {
37         irq_err_count++;
38         printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
39 }
40
41 #ifdef CONFIG_SMP 
42 static char irq_user_affinity[NR_IRQS];
43
44 int irq_select_affinity(unsigned int irq)
45 {
46         static int last_cpu;
47         int cpu = last_cpu + 1;
48
49         if (!irq_desc[irq].chip->set_affinity || irq_user_affinity[irq])
50                 return 1;
51
52         while (!cpu_possible(cpu) ||
53                !cpumask_test_cpu(cpu, irq_default_affinity))
54                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
55         last_cpu = cpu;
56
57         cpumask_copy(irq_desc[irq].affinity, cpumask_of(cpu));
58         irq_desc[irq].chip->set_affinity(irq, cpumask_of(cpu));
59         return 0;
60 }
61 #endif /* CONFIG_SMP */
62
63 int
64 show_interrupts(struct seq_file *p, void *v)
65 {
66 #ifdef CONFIG_SMP
67         int j;
68 #endif
69         int irq = *(loff_t *) v;
70         struct irqaction * action;
71         unsigned long flags;
72
73 #ifdef CONFIG_SMP
74         if (irq == 0) {
75                 seq_puts(p, "           ");
76                 for_each_online_cpu(j)
77                         seq_printf(p, "CPU%d       ", j);
78                 seq_putc(p, '\n');
79         }
80 #endif
81
82         if (irq < ACTUAL_NR_IRQS) {
83                 raw_spin_lock_irqsave(&irq_desc[irq].lock, flags);
84                 action = irq_desc[irq].action;
85                 if (!action) 
86                         goto unlock;
87                 seq_printf(p, "%3d: ", irq);
88 #ifndef CONFIG_SMP
89                 seq_printf(p, "%10u ", kstat_irqs(irq));
90 #else
91                 for_each_online_cpu(j)
92                         seq_printf(p, "%10u ", kstat_irqs_cpu(irq, j));
93 #endif
94                 seq_printf(p, " %14s", irq_desc[irq].chip->name);
95                 seq_printf(p, "  %c%s",
96                         (action->flags & IRQF_DISABLED)?'+':' ',
97                         action->name);
98
99                 for (action=action->next; action; action = action->next) {
100                         seq_printf(p, ", %c%s",
101                                   (action->flags & IRQF_DISABLED)?'+':' ',
102                                    action->name);
103                 }
104
105                 seq_putc(p, '\n');
106 unlock:
107                 raw_spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
108         } else if (irq == ACTUAL_NR_IRQS) {
109 #ifdef CONFIG_SMP
110                 seq_puts(p, "IPI: ");
111                 for_each_online_cpu(j)
112                         seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
113                 seq_putc(p, '\n');
114 #endif
115                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
116         }
117         return 0;
118 }
119
120 /*
121  * handle_irq handles all normal device IRQ's (the special
122  * SMP cross-CPU interrupts have their own specific
123  * handlers).
124  */
125
126 #define MAX_ILLEGAL_IRQS 16
127
128 void
129 handle_irq(int irq)
130 {       
131         /* 
132          * We ack quickly, we don't want the irq controller
133          * thinking we're snobs just because some other CPU has
134          * disabled global interrupts (we have already done the
135          * INT_ACK cycles, it's too late to try to pretend to the
136          * controller that we aren't taking the interrupt).
137          *
138          * 0 return value means that this irq is already being
139          * handled by some other CPU. (or is disabled)
140          */
141         static unsigned int illegal_count=0;
142         
143         if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
144                 irq_err_count++;
145                 illegal_count++;
146                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
147                        irq);
148                 return;
149         }
150
151         irq_enter();
152         /*
153          * __do_IRQ() must be called with IPL_MAX. Note that we do not
154          * explicitly enable interrupts afterwards - some MILO PALcode
155          * (namely LX164 one) seems to have severe problems with RTI
156          * at IPL 0.
157          */
158         local_irq_disable();
159         __do_IRQ(irq);
160         irq_exit();
161 }