tree-wide: fix typos "couter" -> "counter"
[linux-2.6.git] / kernel / irq / spurious.c
1 /*
2  * linux/kernel/irq/spurious.c
3  *
4  * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5  *
6  * This file contains spurious interrupt handling.
7  */
8
9 #include <linux/jiffies.h>
10 #include <linux/irq.h>
11 #include <linux/module.h>
12 #include <linux/kallsyms.h>
13 #include <linux/interrupt.h>
14 #include <linux/moduleparam.h>
15 #include <linux/timer.h>
16
17 static int irqfixup __read_mostly;
18
19 #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
20 static void poll_spurious_irqs(unsigned long dummy);
21 static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
22
23 /*
24  * Recovery handler for misrouted interrupts.
25  */
26 static int try_one_irq(int irq, struct irq_desc *desc)
27 {
28         struct irqaction *action;
29         int ok = 0, work = 0;
30
31         spin_lock(&desc->lock);
32         /* Already running on another processor */
33         if (desc->status & IRQ_INPROGRESS) {
34                 /*
35                  * Already running: If it is shared get the other
36                  * CPU to go looking for our mystery interrupt too
37                  */
38                 if (desc->action && (desc->action->flags & IRQF_SHARED))
39                         desc->status |= IRQ_PENDING;
40                 spin_unlock(&desc->lock);
41                 return ok;
42         }
43         /* Honour the normal IRQ locking */
44         desc->status |= IRQ_INPROGRESS;
45         action = desc->action;
46         spin_unlock(&desc->lock);
47
48         while (action) {
49                 /* Only shared IRQ handlers are safe to call */
50                 if (action->flags & IRQF_SHARED) {
51                         if (action->handler(irq, action->dev_id) ==
52                                 IRQ_HANDLED)
53                                 ok = 1;
54                 }
55                 action = action->next;
56         }
57         local_irq_disable();
58         /* Now clean up the flags */
59         spin_lock(&desc->lock);
60         action = desc->action;
61
62         /*
63          * While we were looking for a fixup someone queued a real
64          * IRQ clashing with our walk:
65          */
66         while ((desc->status & IRQ_PENDING) && action) {
67                 /*
68                  * Perform real IRQ processing for the IRQ we deferred
69                  */
70                 work = 1;
71                 spin_unlock(&desc->lock);
72                 handle_IRQ_event(irq, action);
73                 spin_lock(&desc->lock);
74                 desc->status &= ~IRQ_PENDING;
75         }
76         desc->status &= ~IRQ_INPROGRESS;
77         /*
78          * If we did actual work for the real IRQ line we must let the
79          * IRQ controller clean up too
80          */
81         if (work && desc->chip && desc->chip->end)
82                 desc->chip->end(irq);
83         spin_unlock(&desc->lock);
84
85         return ok;
86 }
87
88 static int misrouted_irq(int irq)
89 {
90         struct irq_desc *desc;
91         int i, ok = 0;
92
93         for_each_irq_desc(i, desc) {
94                 if (!i)
95                          continue;
96
97                 if (i == irq)   /* Already tried */
98                         continue;
99
100                 if (try_one_irq(i, desc))
101                         ok = 1;
102         }
103         /* So the caller can adjust the irq error counts */
104         return ok;
105 }
106
107 static void poll_all_shared_irqs(void)
108 {
109         struct irq_desc *desc;
110         int i;
111
112         for_each_irq_desc(i, desc) {
113                 unsigned int status;
114
115                 if (!i)
116                          continue;
117
118                 /* Racy but it doesn't matter */
119                 status = desc->status;
120                 barrier();
121                 if (!(status & IRQ_SPURIOUS_DISABLED))
122                         continue;
123
124                 try_one_irq(i, desc);
125         }
126 }
127
128 static void poll_spurious_irqs(unsigned long dummy)
129 {
130         poll_all_shared_irqs();
131
132         mod_timer(&poll_spurious_irq_timer,
133                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
134 }
135
136 #ifdef CONFIG_DEBUG_SHIRQ
137 void debug_poll_all_shared_irqs(void)
138 {
139         poll_all_shared_irqs();
140 }
141 #endif
142
143 /*
144  * If 99,900 of the previous 100,000 interrupts have not been handled
145  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
146  * and try to turn the IRQ off.
147  *
148  * (The other 100-of-100,000 interrupts may have been a correctly
149  *  functioning device sharing an IRQ with the failing one)
150  *
151  * Called under desc->lock
152  */
153
154 static void
155 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
156                  irqreturn_t action_ret)
157 {
158         struct irqaction *action;
159
160         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
161                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
162                                 irq, action_ret);
163         } else {
164                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
165                                 "the \"irqpoll\" option)\n", irq);
166         }
167         dump_stack();
168         printk(KERN_ERR "handlers:\n");
169
170         action = desc->action;
171         while (action) {
172                 printk(KERN_ERR "[<%p>]", action->handler);
173                 print_symbol(" (%s)",
174                         (unsigned long)action->handler);
175                 printk("\n");
176                 action = action->next;
177         }
178 }
179
180 static void
181 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
182 {
183         static int count = 100;
184
185         if (count > 0) {
186                 count--;
187                 __report_bad_irq(irq, desc, action_ret);
188         }
189 }
190
191 static inline int
192 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
193                   irqreturn_t action_ret)
194 {
195         struct irqaction *action;
196
197         if (!irqfixup)
198                 return 0;
199
200         /* We didn't actually handle the IRQ - see if it was misrouted? */
201         if (action_ret == IRQ_NONE)
202                 return 1;
203
204         /*
205          * But for 'irqfixup == 2' we also do it for handled interrupts if
206          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
207          * traditional PC timer interrupt.. Legacy)
208          */
209         if (irqfixup < 2)
210                 return 0;
211
212         if (!irq)
213                 return 1;
214
215         /*
216          * Since we don't get the descriptor lock, "action" can
217          * change under us.  We don't really care, but we don't
218          * want to follow a NULL pointer. So tell the compiler to
219          * just load it once by using a barrier.
220          */
221         action = desc->action;
222         barrier();
223         return action && (action->flags & IRQF_IRQPOLL);
224 }
225
226 void note_interrupt(unsigned int irq, struct irq_desc *desc,
227                     irqreturn_t action_ret)
228 {
229         if (unlikely(action_ret != IRQ_HANDLED)) {
230                 /*
231                  * If we are seeing only the odd spurious IRQ caused by
232                  * bus asynchronicity then don't eventually trigger an error,
233                  * otherwise the counter becomes a doomsday timer for otherwise
234                  * working systems
235                  */
236                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
237                         desc->irqs_unhandled = 1;
238                 else
239                         desc->irqs_unhandled++;
240                 desc->last_unhandled = jiffies;
241                 if (unlikely(action_ret != IRQ_NONE))
242                         report_bad_irq(irq, desc, action_ret);
243         }
244
245         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
246                 int ok = misrouted_irq(irq);
247                 if (action_ret == IRQ_NONE)
248                         desc->irqs_unhandled -= ok;
249         }
250
251         desc->irq_count++;
252         if (likely(desc->irq_count < 100000))
253                 return;
254
255         desc->irq_count = 0;
256         if (unlikely(desc->irqs_unhandled > 99900)) {
257                 /*
258                  * The interrupt is stuck
259                  */
260                 __report_bad_irq(irq, desc, action_ret);
261                 /*
262                  * Now kill the IRQ
263                  */
264                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
265                 desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
266                 desc->depth++;
267                 desc->chip->disable(irq);
268
269                 mod_timer(&poll_spurious_irq_timer,
270                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
271         }
272         desc->irqs_unhandled = 0;
273 }
274
275 int noirqdebug __read_mostly;
276
277 int noirqdebug_setup(char *str)
278 {
279         noirqdebug = 1;
280         printk(KERN_INFO "IRQ lockup detection disabled\n");
281
282         return 1;
283 }
284
285 __setup("noirqdebug", noirqdebug_setup);
286 module_param(noirqdebug, bool, 0644);
287 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
288
289 static int __init irqfixup_setup(char *str)
290 {
291         irqfixup = 1;
292         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
293         printk(KERN_WARNING "This may impact system performance.\n");
294
295         return 1;
296 }
297
298 __setup("irqfixup", irqfixup_setup);
299 module_param(irqfixup, int, 0644);
300
301 static int __init irqpoll_setup(char *str)
302 {
303         irqfixup = 2;
304         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
305                                 "enabled\n");
306         printk(KERN_WARNING "This may significantly impact system "
307                                 "performance\n");
308         return 1;
309 }
310
311 __setup("irqpoll", irqpoll_setup);