arch/sh/kernel/irq.c

   1 /* $Id: irq.c,v 1.20 2004/01/13 05:52:11 kkojima Exp $
   2  *
   3  * linux/arch/sh/kernel/irq.c
   4  *
   5  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   6  *
   7  *
   8  * SuperH version:  Copyright (C) 1999  Niibe Yutaka
   9  */
  10
  11 /*
  12  * IRQs are in fact implemented a bit like signal handlers for the kernel.
  13  * Naturally it's not a 1:1 relation, but there are similarities.
  14  */
  15
  16 #include <linux/config.h>
  17 #include <linux/module.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/errno.h>
  20 #include <linux/kernel_stat.h>
  21 #include <linux/signal.h>
  22 #include <linux/sched.h>
  23 #include <linux/ioport.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/timex.h>
  26 #include <linux/mm.h>
  27 #include <linux/slab.h>
  28 #include <linux/random.h>
  29 #include <linux/smp.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/init.h>
  32 #include <linux/seq_file.h>
  33 #include <linux/kallsyms.h>
  34
  35 #include <asm/system.h>
  36 #include <asm/io.h>
  37 #include <asm/bitops.h>
  38 #include <asm/pgalloc.h>
  39 #include <asm/delay.h>
  40 #include <asm/irq.h>
  41 #include <linux/irq.h>
  42
  43 /*
  44  * Controller mappings for all interrupt sources:
  45  */
  46 irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
  47         [0 ... NR_IRQS-1] = {
  48                 .handler = &no_irq_type,
  49                 .lock = SPIN_LOCK_UNLOCKED
  50         }
  51 };
  52
  53 /*
  54  * Special irq handlers.
  55  */
  56
  57 irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
  58 { return IRQ_NONE; }
  59
  60 /*
  61  * Generic no controller code
  62  */
  63
  64 static void enable_none(unsigned int irq) { }
  65 static unsigned int startup_none(unsigned int irq) { return 0; }
  66 static void disable_none(unsigned int irq) { }
  67 static void ack_none(unsigned int irq)
  68 {
  69 /*
  70  * 'what should we do if we get a hw irq event on an illegal vector'.
  71  * each architecture has to answer this themselves, it doesn't deserve
  72  * a generic callback i think.
  73  */
  74         printk("unexpected IRQ trap at vector %02x\n", irq);
  75 }
  76
  77 /* startup is the same as "enable", shutdown is same as "disable" */
  78 #define shutdown_none   disable_none
  79 #define end_none        enable_none
  80
  81 struct hw_interrupt_type no_irq_type = {
  82         "none",
  83         startup_none,
  84         shutdown_none,
  85         enable_none,
  86         disable_none,
  87         ack_none,
  88         end_none
  89 };
  90
  91 /*
  92  * Generic, controller-independent functions:
  93  */
  94
  95 #if defined(CONFIG_PROC_FS)
  96 int show_interrupts(struct seq_file *p, void *v)
  97 {
  98         int i = *(loff_t *) v, j;
  99         struct irqaction * action;
 100         unsigned long flags;
 101
 102         if (i == 0) {
 103                 seq_puts(p, "           ");
 104                 for (j=0; j<NR_CPUS; j++)
 105                         if (cpu_online(j))
 106                                 seq_printf(p, "CPU%d       ",j);
 107                 seq_putc(p, '\n');
 108         }
 109
 110         if (i < ACTUAL_NR_IRQS) {
 111                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 112                 action = irq_desc[i].action;
 113                 if (!action)
 114                         goto unlock;
 115                 seq_printf(p, "%3d: ",i);
 116                 seq_printf(p, "%10u ", kstat_irqs(i));
 117                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
 118                 seq_printf(p, "  %s", action->name);
 119
 120                 for (action=action->next; action; action = action->next)
 121                         seq_printf(p, ", %s", action->name);
 122                 seq_putc(p, '\n');
 123 unlock:
 124                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 125         }
 126         return 0;
 127 }
 128 #endif
 129
 130 /*
 131  * This should really return information about whether
 132  * we should do bottom half handling etc. Right now we
 133  * end up _always_ checking the bottom half, which is a
 134  * waste of time and is not what some drivers would
 135  * prefer.
 136  */
 137 int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action)
 138 {
 139         int status = 1; /* Force the "do bottom halves" bit */
 140         int retval = 0;
 141
 142         if (!(action->flags & SA_INTERRUPT))
 143                 local_irq_enable();
 144
 145         do {
 146                 status |= action->flags;
 147                 retval |= action->handler(irq, action->dev_id, regs);
 148                 action = action->next;
 149         } while (action);
 150
 151         if (status & SA_SAMPLE_RANDOM)
 152                 add_interrupt_randomness(irq);
 153
 154         local_irq_disable();
 155         return retval;
 156 }
 157
 158 static void __report_bad_irq(int irq, irq_desc_t *desc, irqreturn_t action_ret)
 159 {
 160         struct irqaction *action;
 161
 162         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 163                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 164                                 irq, action_ret);
 165         } else {
 166                 printk(KERN_ERR "irq %d: nobody cared!\n", irq);
 167         }
 168         dump_stack();
 169         printk(KERN_ERR "handlers:\n");
 170         action = desc->action;
 171         do {
 172                 printk(KERN_ERR "[<%p>]", action->handler);
 173                 print_symbol(" (%s)",
 174                         (unsigned long)action->handler);
 175                 printk("\n");
 176                 action = action->next;
 177         } while (action);
 178 }
 179
 180 static void report_bad_irq(int irq, irq_desc_t *desc, irqreturn_t action_ret)
 181 {
 182         static int count = 100;
 183
 184         if (count) {
 185                 count--;
 186                 __report_bad_irq(irq, desc, action_ret);
 187         }
 188 }
 189
 190 static int noirqdebug;
 191
 192 static int __init noirqdebug_setup(char *str)
 193 {
 194         noirqdebug = 1;
 195         printk("IRQ lockup detection disabled\n");
 196         return 1;
 197 }
 198
 199 __setup("noirqdebug", noirqdebug_setup);
 200
 201 /*
 202  * If 99,900 of the previous 100,000 interrupts have not been handled then
 203  * assume that the IRQ is stuck in some manner.  Drop a diagnostic and try to
 204  * turn the IRQ off.
 205  *
 206  * (The other 100-of-100,000 interrupts may have been a correctly-functioning
 207  *  device sharing an IRQ with the failing one)
 208  *
 209  * Called under desc->lock
 210  */
 211 static void note_interrupt(int irq, irq_desc_t *desc, irqreturn_t action_ret)
 212 {
 213         if (action_ret != IRQ_HANDLED) {
 214                 desc->irqs_unhandled++;
 215                 if (action_ret != IRQ_NONE)
 216                         report_bad_irq(irq, desc, action_ret);
 217         }
 218
 219         desc->irq_count++;
 220         if (desc->irq_count < 100000)
 221                 return;
 222
 223         desc->irq_count = 0;
 224         if (desc->irqs_unhandled > 99900) {
 225                 /*
 226                  * The interrupt is stuck
 227                  */
 228                 __report_bad_irq(irq, desc, action_ret);
 229                 /*
 230                  * Now kill the IRQ
 231                  */
 232                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 233                 desc->status |= IRQ_DISABLED;
 234                 desc->handler->disable(irq);
 235         }
 236         desc->irqs_unhandled = 0;
 237 }
 238
 239 /*
 240  * Generic enable/disable code: this just calls
 241  * down into the PIC-specific version for the actual
 242  * hardware disable after having gotten the irq
 243  * controller lock.
 244  */
 245 inline void disable_irq_nosync(unsigned int irq)
 246 {
 247         irq_desc_t *desc = irq_desc + irq;
 248         unsigned long flags;
 249
 250         spin_lock_irqsave(&desc->lock, flags);
 251         if (!desc->depth++) {
 252                 desc->status |= IRQ_DISABLED;
 253                 desc->handler->disable(irq);
 254         }
 255         spin_unlock_irqrestore(&desc->lock, flags);
 256 }
 257
 258 /*
 259  * Synchronous version of the above, making sure the IRQ is
 260  * no longer running on any other IRQ..
 261  */
 262 void disable_irq(unsigned int irq)
 263 {
 264         irq_desc_t *desc = irq_desc + irq;
 265         disable_irq_nosync(irq);
 266         if (desc->action)
 267                 synchronize_irq(irq);
 268 }
 269
 270 void enable_irq(unsigned int irq)
 271 {
 272         irq_desc_t *desc = irq_desc + irq;
 273         unsigned long flags;
 274
 275         spin_lock_irqsave(&desc->lock, flags);
 276         switch (desc->depth) {
 277         case 1: {
 278                 unsigned int status = desc->status & ~(IRQ_DISABLED | IRQ_INPROGRESS);
 279                 desc->status = status;
 280                 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
 281                         desc->status = status | IRQ_REPLAY;
 282                         hw_resend_irq(desc->handler,irq);
 283                 }
 284                 desc->handler->enable(irq);
 285                 /* fall-through */
 286         }
 287         default:
 288                 desc->depth--;
 289                 break;
 290         case 0:
 291                 printk("enable_irq() unbalanced from %p\n",
 292                        __builtin_return_address(0));
 293         }
 294         spin_unlock_irqrestore(&desc->lock, flags);
 295 }
 296
 297 /*
 298  * do_IRQ handles all normal device IRQ's.
 299  */
 300 asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
 301                       unsigned long r6, unsigned long r7,
 302                       struct pt_regs regs)
 303 {
 304         /*
 305          * We ack quickly, we don't want the irq controller
 306          * thinking we're snobs just because some other CPU has
 307          * disabled global interrupts (we have already done the
 308          * INT_ACK cycles, it's too late to try to pretend to the
 309          * controller that we aren't taking the interrupt).
 310          *
 311          * 0 return value means that this irq is already being
 312          * handled by some other CPU. (or is disabled)
 313          */
 314         int irq;
 315         irq_desc_t *desc;
 316         struct irqaction * action;
 317         unsigned int status;
 318
 319         irq_enter();
 320
 321 #ifdef CONFIG_PREEMPT
 322         /*
 323          * At this point we're now about to actually call handlers,
 324          * and interrupts might get reenabled during them... bump
 325          * preempt_count to prevent any preemption while the handler
 326          * called here is pending...
 327          */
 328         preempt_disable();
 329 #endif
 330
 331         /* Get IRQ number */
 332         asm volatile("stc       r2_bank, %0\n\t"
 333                      "shlr2     %0\n\t"
 334                      "shlr2     %0\n\t"
 335                      "shlr      %0\n\t"
 336                      "add       #-16, %0\n\t"
 337                      :"=z" (irq));
 338         irq = irq_demux(irq);
 339
 340         kstat_this_cpu.irqs[irq]++;
 341         desc = irq_desc + irq;
 342         spin_lock(&desc->lock);
 343         desc->handler->ack(irq);
 344         /*
 345            REPLAY is when Linux resends an IRQ that was dropped earlier
 346            WAITING is used by probe to mark irqs that are being tested
 347            */
 348         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 349         status |= IRQ_PENDING; /* we _want_ to handle it */
 350
 351         /*
 352          * If the IRQ is disabled for whatever reason, we cannot
 353          * use the action we have.
 354          */
 355         action = NULL;
 356         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 357                 action = desc->action;
 358                 status &= ~IRQ_PENDING; /* we commit to handling */
 359                 status |= IRQ_INPROGRESS; /* we are handling it */
 360         }
 361         desc->status = status;
 362
 363         /*
 364          * If there is no IRQ handler or it was disabled, exit early.
 365            Since we set PENDING, if another processor is handling
 366            a different instance of this same irq, the other processor
 367            will take care of it.
 368          */
 369         if (unlikely(!action))
 370                 goto out;
 371
 372         /*
 373          * Edge triggered interrupts need to remember
 374          * pending events.
 375          * This applies to any hw interrupts that allow a second
 376          * instance of the same irq to arrive while we are in do_IRQ
 377          * or in the handler. But the code here only handles the _second_
 378          * instance of the irq, not the third or fourth. So it is mostly
 379          * useful for irq hardware that does not mask cleanly in an
 380          * SMP environment.
 381          */
 382         for (;;) {
 383                 irqreturn_t action_ret;
 384
 385                 spin_unlock(&desc->lock);
 386                 action_ret = handle_IRQ_event(irq, &regs, action);
 387                 spin_lock(&desc->lock);
 388                 if (!noirqdebug)
 389                         note_interrupt(irq, desc, action_ret);
 390                 if (likely(!(desc->status & IRQ_PENDING)))
 391                         break;
 392                 desc->status &= ~IRQ_PENDING;
 393         }
 394         desc->status &= ~IRQ_INPROGRESS;
 395
 396 out:
 397         /*
 398          * The ->end() handler has to deal with interrupts which got
 399          * disabled while the handler was running.
 400          */
 401         desc->handler->end(irq);
 402         spin_unlock(&desc->lock);
 403
 404         irq_exit();
 405
 406 #ifdef CONFIG_PREEMPT
 407         /*
 408          * We're done with the handlers, interrupts should be
 409          * currently disabled; decrement preempt_count now so
 410          * as we return preemption may be allowed...
 411          */
 412         preempt_enable_no_resched();
 413 #endif
 414
 415         return 1;
 416 }
 417
 418 int request_irq(unsigned int irq,
 419                 irqreturn_t (*handler)(int, void *, struct pt_regs *),
 420                 unsigned long irqflags,
 421                 const char * devname,
 422                 void *dev_id)
 423 {
 424         int retval;
 425         struct irqaction * action;
 426
 427         if (irq >= ACTUAL_NR_IRQS)
 428                 return -EINVAL;
 429         if (!handler)
 430                 return -EINVAL;
 431
 432         action = (struct irqaction *)
 433                         kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
 434         if (!action)
 435                 return -ENOMEM;
 436
 437         action->handler = handler;
 438         action->flags = irqflags;
 439         action->mask = 0;
 440         action->name = devname;
 441         action->next = NULL;
 442         action->dev_id = dev_id;
 443
 444         retval = setup_irq(irq, action);
 445         if (retval)
 446                 kfree(action);
 447         return retval;
 448 }
 449
 450 EXPORT_SYMBOL(request_irq);
 451
 452 void free_irq(unsigned int irq, void *dev_id)
 453 {
 454         irq_desc_t *desc;
 455         struct irqaction **p;
 456         unsigned long flags;
 457
 458         if (irq >= ACTUAL_NR_IRQS)
 459                 return;
 460
 461         desc = irq_desc + irq;
 462         spin_lock_irqsave(&desc->lock,flags);
 463         p = &desc->action;
 464         for (;;) {
 465                 struct irqaction * action = *p;
 466                 if (action) {
 467                         struct irqaction **pp = p;
 468                         p = &action->next;
 469                         if (action->dev_id != dev_id)
 470                                 continue;
 471
 472                         /* Found it - now remove it from the list of entries */
 473                         *pp = action->next;
 474                         if (!desc->action) {
 475                                 desc->status |= IRQ_DISABLED;
 476                                 desc->handler->shutdown(irq);
 477                         }
 478                         spin_unlock_irqrestore(&desc->lock,flags);
 479                         synchronize_irq(irq);
 480                         kfree(action);
 481                         return;
 482                 }
 483                 printk("Trying to free free IRQ%d\n",irq);
 484                 spin_unlock_irqrestore(&desc->lock,flags);
 485                 return;
 486         }
 487 }
 488
 489 EXPORT_SYMBOL(free_irq);
 490
 491 static DECLARE_MUTEX(probe_sem);
 492
 493 /*
 494  * IRQ autodetection code..
 495  *
 496  * This depends on the fact that any interrupt that
 497  * comes in on to an unassigned handler will get stuck
 498  * with "IRQ_WAITING" cleared and the interrupt
 499  * disabled.
 500  */
 501 unsigned long probe_irq_on(void)
 502 {
 503         unsigned int i;
 504         irq_desc_t *desc;
 505         unsigned long val;
 506         unsigned long delay;
 507
 508         down(&probe_sem);
 509         /*
 510          * something may have generated an irq long ago and we want to
 511          * flush such a longstanding irq before considering it as spurious.
 512          */
 513         for (i = NR_IRQS-1; i > 0; i--) {
 514                 desc = irq_desc + i;
 515
 516                 spin_lock_irq(&desc->lock);
 517                 if (!desc->action)
 518                         desc->handler->startup(i);
 519                 spin_unlock_irq(&desc->lock);
 520         }
 521
 522         /* Wait for longstanding interrupts to trigger. */
 523         for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
 524                 /* about 20ms delay */ barrier();
 525
 526         /*
 527          * enable any unassigned irqs
 528          * (we must startup again here because if a longstanding irq
 529          * happened in the previous stage, it may have masked itself)
 530          */
 531         for (i = NR_IRQS-1; i > 0; i--) {
 532                 desc = irq_desc + i;
 533
 534                 spin_lock_irq(&desc->lock);
 535                 if (!desc->action) {
 536                         desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
 537                         if (desc->handler->startup(i))
 538                                 desc->status |= IRQ_PENDING;
 539                 }
 540                 spin_unlock_irq(&desc->lock);
 541         }
 542
 543         /*
 544          * Wait for spurious interrupts to trigger
 545          */
 546         for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
 547                 /* about 100ms delay */ barrier();
 548
 549         /*
 550          * Now filter out any obviously spurious interrupts
 551          */
 552         val = 0;
 553         for (i=0; i<NR_IRQS; i++) {
 554                 unsigned int status;
 555
 556                 desc = irq_desc + i;
 557
 558                 spin_lock_irq(&desc->lock);
 559                 status = desc->status;
 560
 561                 if (status & IRQ_AUTODETECT) {
 562                         /* It triggered already - consider it spurious. */
 563                         if (!(status & IRQ_WAITING)) {
 564                                 desc->status = status & ~IRQ_AUTODETECT;
 565                                 desc->handler->shutdown(i);
 566                         } else
 567                                 if (i < 32)
 568                                         val |= 1 << i;
 569                 }
 570                 spin_unlock_irq(&desc->lock);
 571         }
 572
 573         return val;
 574 }
 575
 576 EXPORT_SYMBOL(probe_irq_on);
 577
 578 int probe_irq_off(unsigned long val)
 579 {
 580         int i, irq_found, nr_irqs;
 581
 582         nr_irqs = 0;
 583         irq_found = 0;
 584         for (i=0; i<NR_IRQS; i++) {
 585                 irq_desc_t *desc = irq_desc + i;
 586                 unsigned int status;
 587
 588                 spin_lock_irq(&desc->lock);
 589                 status = desc->status;
 590
 591                 if (status & IRQ_AUTODETECT) {
 592                         if (!(status & IRQ_WAITING)) {
 593                                 if (!nr_irqs)
 594                                         irq_found = i;
 595                                 nr_irqs++;
 596                         }
 597                         desc->status = status & ~IRQ_AUTODETECT;
 598                         desc->handler->shutdown(i);
 599                 }
 600                 spin_unlock_irq(&desc->lock);
 601         }
 602         up(&probe_sem);
 603
 604         if (nr_irqs > 1)
 605                 irq_found = -irq_found;
 606         return irq_found;
 607 }
 608
 609 EXPORT_SYMBOL(probe_irq_off);
 610
 611 int setup_irq(unsigned int irq, struct irqaction * new)
 612 {
 613         int shared = 0;
 614         struct irqaction *old, **p;
 615         unsigned long flags;
 616         irq_desc_t *desc = irq_desc + irq;
 617
 618         if (desc->handler == &no_irq_type)
 619                 return -ENOSYS;
 620         /*
 621          * Some drivers like serial.c use request_irq() heavily,
 622          * so we have to be careful not to interfere with a
 623          * running system.
 624          */
 625         if (new->flags & SA_SAMPLE_RANDOM) {
 626                 /*
 627                  * This function might sleep, we want to call it first,
 628                  * outside of the atomic block.
 629                  * Yes, this might clear the entropy pool if the wrong
 630                  * driver is attempted to be loaded, without actually
 631                  * installing a new handler, but is this really a problem,
 632                  * only the sysadmin is able to do this.
 633                  */
 634                 rand_initialize_irq(irq);
 635         }
 636
 637         /*
 638          * The following block of code has to be executed atomically
 639          */
 640         spin_lock_irqsave(&desc->lock,flags);
 641         p = &desc->action;
 642         if ((old = *p) != NULL) {
 643                 /* Can't share interrupts unless both agree to */
 644                 if (!(old->flags & new->flags & SA_SHIRQ)) {
 645                         spin_unlock_irqrestore(&desc->lock,flags);
 646                         return -EBUSY;
 647                 }
 648
 649                 /* add new interrupt at end of irq queue */
 650                 do {
 651                         p = &old->next;
 652                         old = *p;
 653                 } while (old);
 654                 shared = 1;
 655         }
 656
 657         *p = new;
 658
 659         if (!shared) {
 660                 desc->depth = 0;
 661                 desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | IRQ_WAITING | IRQ_INPROGRESS);
 662                 desc->handler->startup(irq);
 663         }
 664         spin_unlock_irqrestore(&desc->lock,flags);
 665         return 0;
 666 }
 667
 668 #if defined(CONFIG_PROC_FS) && defined(CONFIG_SYSCTL)
 669
 670 void init_irq_proc(void)
 671 {
 672 }
 673 #endif
 674
 675 /* Taken from the 2.5 alpha port */
 676 #ifdef CONFIG_SMP
 677 void synchronize_irq(unsigned int irq)
 678 {
 679         /* is there anything to synchronize with? */
 680         if (!irq_desc[irq].action)
 681                 return;
 682
 683         while (irq_desc[irq].status & IRQ_INPROGRESS)
 684                 barrier();
 685 }
 686 #endif