Merge branch 'for-davem' of ssh://master.kernel.org/pub/scm/linux/kernel/git/linville...
[linux-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 DEFINE_PER_CPU(unsigned long, irq_pmi_count);
35
36 void 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 
43 static char irq_user_affinity[NR_IRQS];
44
45 int irq_select_affinity(unsigned int irq)
46 {
47         struct irq_data *data = irq_get_irq_data(irq);
48         struct irq_chip *chip;
49         static int last_cpu;
50         int cpu = last_cpu + 1;
51
52         if (!data)
53                 return 1;
54         chip = irq_data_get_irq_chip(data);
55
56         if (!chip->irq_set_affinity || irq_user_affinity[irq])
57                 return 1;
58
59         while (!cpu_possible(cpu) ||
60                !cpumask_test_cpu(cpu, irq_default_affinity))
61                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
62         last_cpu = cpu;
63
64         cpumask_copy(data->affinity, cpumask_of(cpu));
65         chip->irq_set_affinity(data, cpumask_of(cpu), false);
66         return 0;
67 }
68 #endif /* CONFIG_SMP */
69
70 int
71 show_interrupts(struct seq_file *p, void *v)
72 {
73         int j;
74         int irq = *(loff_t *) v;
75         struct irqaction * action;
76         struct irq_desc *desc;
77         unsigned long flags;
78
79 #ifdef CONFIG_SMP
80         if (irq == 0) {
81                 seq_puts(p, "           ");
82                 for_each_online_cpu(j)
83                         seq_printf(p, "CPU%d       ", j);
84                 seq_putc(p, '\n');
85         }
86 #endif
87
88         if (irq < ACTUAL_NR_IRQS) {
89                 desc = irq_to_desc(irq);
90
91                 if (!desc)
92                         return 0;
93
94                 raw_spin_lock_irqsave(&desc->lock, flags);
95                 action = desc->action;
96                 if (!action) 
97                         goto unlock;
98                 seq_printf(p, "%3d: ", irq);
99 #ifndef CONFIG_SMP
100                 seq_printf(p, "%10u ", kstat_irqs(irq));
101 #else
102                 for_each_online_cpu(j)
103                         seq_printf(p, "%10u ", kstat_irqs_cpu(irq, j));
104 #endif
105                 seq_printf(p, " %14s", get_irq_desc_chip(desc)->name);
106                 seq_printf(p, "  %c%s",
107                         (action->flags & IRQF_DISABLED)?'+':' ',
108                         action->name);
109
110                 for (action=action->next; action; action = action->next) {
111                         seq_printf(p, ", %c%s",
112                                   (action->flags & IRQF_DISABLED)?'+':' ',
113                                    action->name);
114                 }
115
116                 seq_putc(p, '\n');
117 unlock:
118                 raw_spin_unlock_irqrestore(&desc->lock, flags);
119         } else if (irq == ACTUAL_NR_IRQS) {
120 #ifdef CONFIG_SMP
121                 seq_puts(p, "IPI: ");
122                 for_each_online_cpu(j)
123                         seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
124                 seq_putc(p, '\n');
125 #endif
126                 seq_puts(p, "PMI: ");
127                 for_each_online_cpu(j)
128                         seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
129                 seq_puts(p, "          Performance Monitoring\n");
130                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
131         }
132         return 0;
133 }
134
135 /*
136  * handle_irq handles all normal device IRQ's (the special
137  * SMP cross-CPU interrupts have their own specific
138  * handlers).
139  */
140
141 #define MAX_ILLEGAL_IRQS 16
142
143 void
144 handle_irq(int irq)
145 {       
146         /* 
147          * We ack quickly, we don't want the irq controller
148          * thinking we're snobs just because some other CPU has
149          * disabled global interrupts (we have already done the
150          * INT_ACK cycles, it's too late to try to pretend to the
151          * controller that we aren't taking the interrupt).
152          *
153          * 0 return value means that this irq is already being
154          * handled by some other CPU. (or is disabled)
155          */
156         static unsigned int illegal_count=0;
157         struct irq_desc *desc = irq_to_desc(irq);
158         
159         if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
160             illegal_count < MAX_ILLEGAL_IRQS)) {
161                 irq_err_count++;
162                 illegal_count++;
163                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
164                        irq);
165                 return;
166         }
167
168         /*
169          * From here we must proceed with IPL_MAX. Note that we do not
170          * explicitly enable interrupts afterwards - some MILO PALcode
171          * (namely LX164 one) seems to have severe problems with RTI
172          * at IPL 0.
173          */
174         local_irq_disable();
175         irq_enter();
176         generic_handle_irq_desc(irq, desc);
177         irq_exit();
178 }