Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab...
[linux-2.6] / 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 (!desc)
95                         continue;
96
97                 if (!i)
98                          continue;
99
100                 if (i == irq)   /* Already tried */
101                         continue;
102
103                 if (try_one_irq(i, desc))
104                         ok = 1;
105         }
106         /* So the caller can adjust the irq error counts */
107         return ok;
108 }
109
110 static void poll_spurious_irqs(unsigned long dummy)
111 {
112         struct irq_desc *desc;
113         int i;
114
115         for_each_irq_desc(i, desc) {
116                 unsigned int status;
117
118                 if (!desc)
119                         continue;
120                 if (!i)
121                          continue;
122
123                 /* Racy but it doesn't matter */
124                 status = desc->status;
125                 barrier();
126                 if (!(status & IRQ_SPURIOUS_DISABLED))
127                         continue;
128
129                 try_one_irq(i, desc);
130         }
131
132         mod_timer(&poll_spurious_irq_timer,
133                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
134 }
135
136 /*
137  * If 99,900 of the previous 100,000 interrupts have not been handled
138  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
139  * and try to turn the IRQ off.
140  *
141  * (The other 100-of-100,000 interrupts may have been a correctly
142  *  functioning device sharing an IRQ with the failing one)
143  *
144  * Called under desc->lock
145  */
146
147 static void
148 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
149                  irqreturn_t action_ret)
150 {
151         struct irqaction *action;
152
153         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
154                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
155                                 irq, action_ret);
156         } else {
157                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
158                                 "the \"irqpoll\" option)\n", irq);
159         }
160         dump_stack();
161         printk(KERN_ERR "handlers:\n");
162
163         action = desc->action;
164         while (action) {
165                 printk(KERN_ERR "[<%p>]", action->handler);
166                 print_symbol(" (%s)",
167                         (unsigned long)action->handler);
168                 printk("\n");
169                 action = action->next;
170         }
171 }
172
173 static void
174 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
175 {
176         static int count = 100;
177
178         if (count > 0) {
179                 count--;
180                 __report_bad_irq(irq, desc, action_ret);
181         }
182 }
183
184 static inline int
185 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
186                   irqreturn_t action_ret)
187 {
188         struct irqaction *action;
189
190         if (!irqfixup)
191                 return 0;
192
193         /* We didn't actually handle the IRQ - see if it was misrouted? */
194         if (action_ret == IRQ_NONE)
195                 return 1;
196
197         /*
198          * But for 'irqfixup == 2' we also do it for handled interrupts if
199          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
200          * traditional PC timer interrupt.. Legacy)
201          */
202         if (irqfixup < 2)
203                 return 0;
204
205         if (!irq)
206                 return 1;
207
208         /*
209          * Since we don't get the descriptor lock, "action" can
210          * change under us.  We don't really care, but we don't
211          * want to follow a NULL pointer. So tell the compiler to
212          * just load it once by using a barrier.
213          */
214         action = desc->action;
215         barrier();
216         return action && (action->flags & IRQF_IRQPOLL);
217 }
218
219 void note_interrupt(unsigned int irq, struct irq_desc *desc,
220                     irqreturn_t action_ret)
221 {
222         if (unlikely(action_ret != IRQ_HANDLED)) {
223                 /*
224                  * If we are seeing only the odd spurious IRQ caused by
225                  * bus asynchronicity then don't eventually trigger an error,
226                  * otherwise the couter becomes a doomsday timer for otherwise
227                  * working systems
228                  */
229                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
230                         desc->irqs_unhandled = 1;
231                 else
232                         desc->irqs_unhandled++;
233                 desc->last_unhandled = jiffies;
234                 if (unlikely(action_ret != IRQ_NONE))
235                         report_bad_irq(irq, desc, action_ret);
236         }
237
238         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
239                 int ok = misrouted_irq(irq);
240                 if (action_ret == IRQ_NONE)
241                         desc->irqs_unhandled -= ok;
242         }
243
244         desc->irq_count++;
245         if (likely(desc->irq_count < 100000))
246                 return;
247
248         desc->irq_count = 0;
249         if (unlikely(desc->irqs_unhandled > 99900)) {
250                 /*
251                  * The interrupt is stuck
252                  */
253                 __report_bad_irq(irq, desc, action_ret);
254                 /*
255                  * Now kill the IRQ
256                  */
257                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
258                 desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
259                 desc->depth++;
260                 desc->chip->disable(irq);
261
262                 mod_timer(&poll_spurious_irq_timer,
263                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
264         }
265         desc->irqs_unhandled = 0;
266 }
267
268 int noirqdebug __read_mostly;
269
270 int noirqdebug_setup(char *str)
271 {
272         noirqdebug = 1;
273         printk(KERN_INFO "IRQ lockup detection disabled\n");
274
275         return 1;
276 }
277
278 __setup("noirqdebug", noirqdebug_setup);
279 module_param(noirqdebug, bool, 0644);
280 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
281
282 static int __init irqfixup_setup(char *str)
283 {
284         irqfixup = 1;
285         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
286         printk(KERN_WARNING "This may impact system performance.\n");
287
288         return 1;
289 }
290
291 __setup("irqfixup", irqfixup_setup);
292 module_param(irqfixup, int, 0644);
293 MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode, 2: irqpoll mode");
294
295 static int __init irqpoll_setup(char *str)
296 {
297         irqfixup = 2;
298         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
299                                 "enabled\n");
300         printk(KERN_WARNING "This may significantly impact system "
301                                 "performance\n");
302         return 1;
303 }
304
305 __setup("irqpoll", irqpoll_setup);