git.oblomov.eu Git - linux-2.6/blob - 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);