f88efb135b702b2e4e9610dd9df490331df71c5c
[linux-2.6.git] / arch / arm / kernel / irq.c
1 /*
2  *  linux/arch/arm/kernel/irq.c
3  *
4  *  Copyright (C) 1992 Linus Torvalds
5  *  Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
6  *
7  *  Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
8  *  Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
9  *  Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  *
15  *  This file contains the code used by various IRQ handling routines:
16  *  asking for different IRQ's should be done through these routines
17  *  instead of just grabbing them. Thus setups with different IRQ numbers
18  *  shouldn't result in any weird surprises, and installing new handlers
19  *  should be easier.
20  *
21  *  IRQ's are in fact implemented a bit like signal handlers for the kernel.
22  *  Naturally it's not a 1:1 relation, but there are similarities.
23  */
24 #include <linux/kernel_stat.h>
25 #include <linux/module.h>
26 #include <linux/signal.h>
27 #include <linux/ioport.h>
28 #include <linux/interrupt.h>
29 #include <linux/irq.h>
30 #include <linux/slab.h>
31 #include <linux/random.h>
32 #include <linux/smp.h>
33 #include <linux/init.h>
34 #include <linux/seq_file.h>
35 #include <linux/errno.h>
36 #include <linux/list.h>
37 #include <linux/kallsyms.h>
38 #include <linux/proc_fs.h>
39
40 #include <asm/system.h>
41 #include <asm/mach/irq.h>
42 #include <asm/mach/time.h>
43
44 /*
45  * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
46  */
47 #ifndef irq_finish
48 #define irq_finish(irq) do { } while (0)
49 #endif
50
51 void (*init_arch_irq)(void) __initdata = NULL;
52 unsigned long irq_err_count;
53
54 int show_interrupts(struct seq_file *p, void *v)
55 {
56         int i = *(loff_t *) v, cpu;
57         struct irqaction * action;
58         unsigned long flags;
59
60         if (i == 0) {
61                 char cpuname[12];
62
63                 seq_printf(p, "    ");
64                 for_each_present_cpu(cpu) {
65                         sprintf(cpuname, "CPU%d", cpu);
66                         seq_printf(p, " %10s", cpuname);
67                 }
68                 seq_putc(p, '\n');
69         }
70
71         if (i < NR_IRQS) {
72                 spin_lock_irqsave(&irq_desc[i].lock, flags);
73                 action = irq_desc[i].action;
74                 if (!action)
75                         goto unlock;
76
77                 seq_printf(p, "%3d: ", i);
78                 for_each_present_cpu(cpu)
79                         seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
80                 seq_printf(p, " %10s", irq_desc[i].chip->name ? : "-");
81                 seq_printf(p, "  %s", action->name);
82                 for (action = action->next; action; action = action->next)
83                         seq_printf(p, ", %s", action->name);
84
85                 seq_putc(p, '\n');
86 unlock:
87                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
88         } else if (i == NR_IRQS) {
89 #ifdef CONFIG_ARCH_ACORN
90                 show_fiq_list(p, v);
91 #endif
92 #ifdef CONFIG_SMP
93                 show_ipi_list(p);
94                 show_local_irqs(p);
95 #endif
96                 seq_printf(p, "Err: %10lu\n", irq_err_count);
97         }
98         return 0;
99 }
100
101 /* Handle bad interrupts */
102 static struct irq_desc bad_irq_desc = {
103         .handle_irq = handle_bad_irq,
104         .lock = SPIN_LOCK_UNLOCKED
105 };
106
107 /*
108  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
109  * come via this function.  Instead, they should provide their
110  * own 'handler'
111  */
112 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
113 {
114         struct pt_regs *old_regs = set_irq_regs(regs);
115         struct irq_desc *desc = irq_desc + irq;
116
117         /*
118          * Some hardware gives randomly wrong interrupts.  Rather
119          * than crashing, do something sensible.
120          */
121         if (irq >= NR_IRQS)
122                 desc = &bad_irq_desc;
123
124         irq_enter();
125
126         desc_handle_irq(irq, desc);
127
128         /* AT91 specific workaround */
129         irq_finish(irq);
130
131         irq_exit();
132         set_irq_regs(old_regs);
133 }
134
135 void set_irq_flags(unsigned int irq, unsigned int iflags)
136 {
137         struct irq_desc *desc;
138         unsigned long flags;
139
140         if (irq >= NR_IRQS) {
141                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
142                 return;
143         }
144
145         desc = irq_desc + irq;
146         spin_lock_irqsave(&desc->lock, flags);
147         desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
148         if (iflags & IRQF_VALID)
149                 desc->status &= ~IRQ_NOREQUEST;
150         if (iflags & IRQF_PROBE)
151                 desc->status &= ~IRQ_NOPROBE;
152         if (!(iflags & IRQF_NOAUTOEN))
153                 desc->status &= ~IRQ_NOAUTOEN;
154         spin_unlock_irqrestore(&desc->lock, flags);
155 }
156
157 void __init init_IRQ(void)
158 {
159         int irq;
160
161         for (irq = 0; irq < NR_IRQS; irq++)
162                 irq_desc[irq].status |= IRQ_NOREQUEST | IRQ_NOPROBE;
163
164 #ifdef CONFIG_SMP
165         bad_irq_desc.affinity = CPU_MASK_ALL;
166         bad_irq_desc.cpu = smp_processor_id();
167 #endif
168         init_arch_irq();
169 }
170
171 #ifdef CONFIG_HOTPLUG_CPU
172
173 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
174 {
175         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
176
177         spin_lock_irq(&desc->lock);
178         desc->chip->set_affinity(irq, cpumask_of_cpu(cpu));
179         spin_unlock_irq(&desc->lock);
180 }
181
182 /*
183  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
184  * the affinity settings do not allow other CPUs, force them onto any
185  * available CPU.
186  */
187 void migrate_irqs(void)
188 {
189         unsigned int i, cpu = smp_processor_id();
190
191         for (i = 0; i < NR_IRQS; i++) {
192                 struct irq_desc *desc = irq_desc + i;
193
194                 if (desc->cpu == cpu) {
195                         unsigned int newcpu = any_online_cpu(desc->affinity);
196
197                         if (newcpu == NR_CPUS) {
198                                 if (printk_ratelimit())
199                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
200                                                i, cpu);
201
202                                 cpus_setall(desc->affinity);
203                                 newcpu = any_online_cpu(desc->affinity);
204                         }
205
206                         route_irq(desc, i, newcpu);
207                 }
208         }
209 }
210 #endif /* CONFIG_HOTPLUG_CPU */