4bb723eadad13c73dc5da7ba61ef2e2367fbc9ba
[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 #ifdef CONFIG_CPUMASK_OFFSTACK
108 /* We are not allocating bad_irq_desc.affinity or .pending_mask */
109 #error "ARM architecture does not support CONFIG_CPUMASK_OFFSTACK."
110 #endif
111
112 /*
113  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
114  * come via this function.  Instead, they should provide their
115  * own 'handler'
116  */
117 asmlinkage void __exception asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
118 {
119         struct pt_regs *old_regs = set_irq_regs(regs);
120
121         irq_enter();
122
123         /*
124          * Some hardware gives randomly wrong interrupts.  Rather
125          * than crashing, do something sensible.
126          */
127         if (irq >= NR_IRQS)
128                 handle_bad_irq(irq, &bad_irq_desc);
129         else
130                 generic_handle_irq(irq);
131
132         /* AT91 specific workaround */
133         irq_finish(irq);
134
135         irq_exit();
136         set_irq_regs(old_regs);
137 }
138
139 void set_irq_flags(unsigned int irq, unsigned int iflags)
140 {
141         struct irq_desc *desc;
142         unsigned long flags;
143
144         if (irq >= NR_IRQS) {
145                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
146                 return;
147         }
148
149         desc = irq_desc + irq;
150         spin_lock_irqsave(&desc->lock, flags);
151         desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
152         if (iflags & IRQF_VALID)
153                 desc->status &= ~IRQ_NOREQUEST;
154         if (iflags & IRQF_PROBE)
155                 desc->status &= ~IRQ_NOPROBE;
156         if (!(iflags & IRQF_NOAUTOEN))
157                 desc->status &= ~IRQ_NOAUTOEN;
158         spin_unlock_irqrestore(&desc->lock, flags);
159 }
160
161 void __init init_IRQ(void)
162 {
163         int irq;
164
165         for (irq = 0; irq < NR_IRQS; irq++)
166                 irq_desc[irq].status |= IRQ_NOREQUEST | IRQ_NOPROBE;
167
168 #ifdef CONFIG_SMP
169         cpumask_setall(bad_irq_desc.affinity);
170         bad_irq_desc.cpu = smp_processor_id();
171 #endif
172         init_arch_irq();
173 }
174
175 #ifdef CONFIG_HOTPLUG_CPU
176
177 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
178 {
179         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
180
181         spin_lock_irq(&desc->lock);
182         desc->chip->set_affinity(irq, cpumask_of(cpu));
183         spin_unlock_irq(&desc->lock);
184 }
185
186 /*
187  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
188  * the affinity settings do not allow other CPUs, force them onto any
189  * available CPU.
190  */
191 void migrate_irqs(void)
192 {
193         unsigned int i, cpu = smp_processor_id();
194
195         for (i = 0; i < NR_IRQS; i++) {
196                 struct irq_desc *desc = irq_desc + i;
197
198                 if (desc->cpu == cpu) {
199                         unsigned int newcpu = cpumask_any_and(desc->affinity,
200                                                               cpu_online_mask);
201                         if (newcpu >= nr_cpu_ids) {
202                                 if (printk_ratelimit())
203                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
204                                                i, cpu);
205
206                                 cpumask_setall(desc->affinity);
207                                 newcpu = cpumask_any_and(desc->affinity,
208                                                          cpu_online_mask);
209                         }
210
211                         route_irq(desc, i, newcpu);
212                 }
213         }
214 }
215 #endif /* CONFIG_HOTPLUG_CPU */