arch/powerpc/kernel/irq.c

   1 /*
   2  *  Derived from arch/i386/kernel/irq.c
   3  *    Copyright (C) 1992 Linus Torvalds
   4  *  Adapted from arch/i386 by Gary Thomas
   5  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   6  *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
   7  *    Copyright (C) 1996-2001 Cort Dougan
   8  *  Adapted for Power Macintosh by Paul Mackerras
   9  *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version
  14  * 2 of the License, or (at your option) any later version.
  15  *
  16  * This file contains the code used by various IRQ handling routines:
  17  * asking for different IRQ's should be done through these routines
  18  * instead of just grabbing them. Thus setups with different IRQ numbers
  19  * shouldn't result in any weird surprises, and installing new handlers
  20  * should be easier.
  21  *
  22  * The MPC8xx has an interrupt mask in the SIU.  If a bit is set, the
  23  * interrupt is _enabled_.  As expected, IRQ0 is bit 0 in the 32-bit
  24  * mask register (of which only 16 are defined), hence the weird shifting
  25  * and complement of the cached_irq_mask.  I want to be able to stuff
  26  * this right into the SIU SMASK register.
  27  * Many of the prep/chrp functions are conditional compiled on CONFIG_8xx
  28  * to reduce code space and undefined function references.
  29  */
  30
  31 #undef DEBUG
  32
  33 #include <linux/module.h>
  34 #include <linux/threads.h>
  35 #include <linux/kernel_stat.h>
  36 #include <linux/signal.h>
  37 #include <linux/sched.h>
  38 #include <linux/ptrace.h>
  39 #include <linux/ioport.h>
  40 #include <linux/interrupt.h>
  41 #include <linux/timex.h>
  42 #include <linux/init.h>
  43 #include <linux/slab.h>
  44 #include <linux/delay.h>
  45 #include <linux/irq.h>
  46 #include <linux/seq_file.h>
  47 #include <linux/cpumask.h>
  48 #include <linux/profile.h>
  49 #include <linux/bitops.h>
  50 #include <linux/list.h>
  51 #include <linux/radix-tree.h>
  52 #include <linux/mutex.h>
  53 #include <linux/bootmem.h>
  54 #include <linux/pci.h>
  55 #include <linux/debugfs.h>
  56
  57 #include <asm/uaccess.h>
  58 #include <asm/system.h>
  59 #include <asm/io.h>
  60 #include <asm/pgtable.h>
  61 #include <asm/irq.h>
  62 #include <asm/cache.h>
  63 #include <asm/prom.h>
  64 #include <asm/ptrace.h>
  65 #include <asm/machdep.h>
  66 #include <asm/udbg.h>
  67 #ifdef CONFIG_PPC64
  68 #include <asm/paca.h>
  69 #include <asm/firmware.h>
  70 #include <asm/lv1call.h>
  71 #endif
  72
  73 int __irq_offset_value;
  74 static int ppc_spurious_interrupts;
  75
  76 #ifdef CONFIG_PPC32
  77 EXPORT_SYMBOL(__irq_offset_value);
  78 atomic_t ppc_n_lost_interrupts;
  79
  80 #ifdef CONFIG_TAU_INT
  81 extern int tau_initialized;
  82 extern int tau_interrupts(int);
  83 #endif
  84 #endif /* CONFIG_PPC32 */
  85
  86 #ifdef CONFIG_PPC64
  87 EXPORT_SYMBOL(irq_desc);
  88
  89 int distribute_irqs = 1;
  90
  91 static inline notrace unsigned long get_hard_enabled(void)
  92 {
  93         unsigned long enabled;
  94
  95         __asm__ __volatile__("lbz %0,%1(13)"
  96         : "=r" (enabled) : "i" (offsetof(struct paca_struct, hard_enabled)));
  97
  98         return enabled;
  99 }
 100
 101 static inline notrace void set_soft_enabled(unsigned long enable)
 102 {
 103         __asm__ __volatile__("stb %0,%1(13)"
 104         : : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
 105 }
 106
 107 notrace void raw_local_irq_restore(unsigned long en)
 108 {
 109         /*
 110          * get_paca()->soft_enabled = en;
 111          * Is it ever valid to use local_irq_restore(0) when soft_enabled is 1?
 112          * That was allowed before, and in such a case we do need to take care
 113          * that gcc will set soft_enabled directly via r13, not choose to use
 114          * an intermediate register, lest we're preempted to a different cpu.
 115          */
 116         set_soft_enabled(en);
 117         if (!en)
 118                 return;
 119
 120         if (firmware_has_feature(FW_FEATURE_ISERIES)) {
 121                 /*
 122                  * Do we need to disable preemption here?  Not really: in the
 123                  * unlikely event that we're preempted to a different cpu in
 124                  * between getting r13, loading its lppaca_ptr, and loading
 125                  * its any_int, we might call iseries_handle_interrupts without
 126                  * an interrupt pending on the new cpu, but that's no disaster,
 127                  * is it?  And the business of preempting us off the old cpu
 128                  * would itself involve a local_irq_restore which handles the
 129                  * interrupt to that cpu.
 130                  *
 131                  * But use "local_paca->lppaca_ptr" instead of "get_lppaca()"
 132                  * to avoid any preemption checking added into get_paca().
 133                  */
 134                 if (local_paca->lppaca_ptr->int_dword.any_int)
 135                         iseries_handle_interrupts();
 136         }
 137
 138         /*
 139          * if (get_paca()->hard_enabled) return;
 140          * But again we need to take care that gcc gets hard_enabled directly
 141          * via r13, not choose to use an intermediate register, lest we're
 142          * preempted to a different cpu in between the two instructions.
 143          */
 144         if (get_hard_enabled())
 145                 return;
 146
 147         /*
 148          * Need to hard-enable interrupts here.  Since currently disabled,
 149          * no need to take further asm precautions against preemption; but
 150          * use local_paca instead of get_paca() to avoid preemption checking.
 151          */
 152         local_paca->hard_enabled = en;
 153         if ((int)mfspr(SPRN_DEC) < 0)
 154                 mtspr(SPRN_DEC, 1);
 155
 156         /*
 157          * Force the delivery of pending soft-disabled interrupts on PS3.
 158          * Any HV call will have this side effect.
 159          */
 160         if (firmware_has_feature(FW_FEATURE_PS3_LV1)) {
 161                 u64 tmp;
 162                 lv1_get_version_info(&tmp);
 163         }
 164
 165         __hard_irq_enable();
 166 }
 167 EXPORT_SYMBOL(raw_local_irq_restore);
 168 #endif /* CONFIG_PPC64 */
 169
 170 int show_interrupts(struct seq_file *p, void *v)
 171 {
 172         int i = *(loff_t *)v, j;
 173         struct irqaction *action;
 174         struct irq_desc *desc;
 175         unsigned long flags;
 176
 177         if (i == 0) {
 178                 seq_puts(p, "           ");
 179                 for_each_online_cpu(j)
 180                         seq_printf(p, "CPU%d       ", j);
 181                 seq_putc(p, '\n');
 182         }
 183
 184         if (i < NR_IRQS) {
 185                 desc = get_irq_desc(i);
 186                 spin_lock_irqsave(&desc->lock, flags);
 187                 action = desc->action;
 188                 if (!action || !action->handler)
 189                         goto skip;
 190                 seq_printf(p, "%3d: ", i);
 191 #ifdef CONFIG_SMP
 192                 for_each_online_cpu(j)
 193                         seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
 194 #else
 195                 seq_printf(p, "%10u ", kstat_irqs(i));
 196 #endif /* CONFIG_SMP */
 197                 if (desc->chip)
 198                         seq_printf(p, " %s ", desc->chip->typename);
 199                 else
 200                         seq_puts(p, "  None      ");
 201                 seq_printf(p, "%s", (desc->status & IRQ_LEVEL) ? "Level " : "Edge  ");
 202                 seq_printf(p, "    %s", action->name);
 203                 for (action = action->next; action; action = action->next)
 204                         seq_printf(p, ", %s", action->name);
 205                 seq_putc(p, '\n');
 206 skip:
 207                 spin_unlock_irqrestore(&desc->lock, flags);
 208         } else if (i == NR_IRQS) {
 209 #if defined(CONFIG_PPC32) && defined(CONFIG_TAU_INT)
 210                 if (tau_initialized){
 211                         seq_puts(p, "TAU: ");
 212                         for_each_online_cpu(j)
 213                                 seq_printf(p, "%10u ", tau_interrupts(j));
 214                         seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
 215                 }
 216 #endif /* CONFIG_PPC32 && CONFIG_TAU_INT*/
 217                 seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
 218         }
 219         return 0;
 220 }
 221
 222 #ifdef CONFIG_HOTPLUG_CPU
 223 void fixup_irqs(cpumask_t map)
 224 {
 225         unsigned int irq;
 226         static int warned;
 227
 228         for_each_irq(irq) {
 229                 cpumask_t mask;
 230
 231                 if (irq_desc[irq].status & IRQ_PER_CPU)
 232                         continue;
 233
 234                 cpumask_and(&mask, irq_desc[irq].affinity, &map);
 235                 if (any_online_cpu(mask) == NR_CPUS) {
 236                         printk("Breaking affinity for irq %i\n", irq);
 237                         mask = map;
 238                 }
 239                 if (irq_desc[irq].chip->set_affinity)
 240                         irq_desc[irq].chip->set_affinity(irq, &mask);
 241                 else if (irq_desc[irq].action && !(warned++))
 242                         printk("Cannot set affinity for irq %i\n", irq);
 243         }
 244
 245         local_irq_enable();
 246         mdelay(1);
 247         local_irq_disable();
 248 }
 249 #endif
 250
 251 void do_IRQ(struct pt_regs *regs)
 252 {
 253         struct pt_regs *old_regs = set_irq_regs(regs);
 254         unsigned int irq;
 255 #ifdef CONFIG_IRQSTACKS
 256         struct thread_info *curtp, *irqtp;
 257 #endif
 258
 259         irq_enter();
 260
 261 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 262         /* Debugging check for stack overflow: is there less than 2KB free? */
 263         {
 264                 long sp;
 265
 266                 sp = __get_SP() & (THREAD_SIZE-1);
 267
 268                 if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
 269                         printk("do_IRQ: stack overflow: %ld\n",
 270                                 sp - sizeof(struct thread_info));
 271                         dump_stack();
 272                 }
 273         }
 274 #endif
 275
 276         /*
 277          * Every platform is required to implement ppc_md.get_irq.
 278          * This function will either return an irq number or NO_IRQ to
 279          * indicate there are no more pending.
 280          * The value NO_IRQ_IGNORE is for buggy hardware and means that this
 281          * IRQ has already been handled. -- Tom
 282          */
 283         irq = ppc_md.get_irq();
 284
 285         if (irq != NO_IRQ && irq != NO_IRQ_IGNORE) {
 286 #ifdef CONFIG_IRQSTACKS
 287                 /* Switch to the irq stack to handle this */
 288                 curtp = current_thread_info();
 289                 irqtp = hardirq_ctx[smp_processor_id()];
 290                 if (curtp != irqtp) {
 291                         struct irq_desc *desc = irq_desc + irq;
 292                         void *handler = desc->handle_irq;
 293                         unsigned long saved_sp_limit = current->thread.ksp_limit;
 294                         if (handler == NULL)
 295                                 handler = &__do_IRQ;
 296                         irqtp->task = curtp->task;
 297                         irqtp->flags = 0;
 298
 299                         /* Copy the softirq bits in preempt_count so that the
 300                          * softirq checks work in the hardirq context.
 301                          */
 302                         irqtp->preempt_count =
 303                                 (irqtp->preempt_count & ~SOFTIRQ_MASK) |
 304                                 (curtp->preempt_count & SOFTIRQ_MASK);
 305
 306                         current->thread.ksp_limit = (unsigned long)irqtp +
 307                                 _ALIGN_UP(sizeof(struct thread_info), 16);
 308                         call_handle_irq(irq, desc, irqtp, handler);
 309                         current->thread.ksp_limit = saved_sp_limit;
 310                         irqtp->task = NULL;
 311
 312
 313                         /* Set any flag that may have been set on the
 314                          * alternate stack
 315                          */
 316                         if (irqtp->flags)
 317                                 set_bits(irqtp->flags, &curtp->flags);
 318                 } else
 319 #endif
 320                         generic_handle_irq(irq);
 321         } else if (irq != NO_IRQ_IGNORE)
 322                 /* That's not SMP safe ... but who cares ? */
 323                 ppc_spurious_interrupts++;
 324
 325         irq_exit();
 326         set_irq_regs(old_regs);
 327
 328 #ifdef CONFIG_PPC_ISERIES
 329         if (firmware_has_feature(FW_FEATURE_ISERIES) &&
 330                         get_lppaca()->int_dword.fields.decr_int) {
 331                 get_lppaca()->int_dword.fields.decr_int = 0;
 332                 /* Signal a fake decrementer interrupt */
 333                 timer_interrupt(regs);
 334         }
 335 #endif
 336 }
 337
 338 void __init init_IRQ(void)
 339 {
 340         if (ppc_md.init_IRQ)
 341                 ppc_md.init_IRQ();
 342
 343         exc_lvl_ctx_init();
 344
 345         irq_ctx_init();
 346 }
 347
 348 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
 349 struct thread_info   *critirq_ctx[NR_CPUS] __read_mostly;
 350 struct thread_info    *dbgirq_ctx[NR_CPUS] __read_mostly;
 351 struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;
 352
 353 void exc_lvl_ctx_init(void)
 354 {
 355         struct thread_info *tp;
 356         int i;
 357
 358         for_each_possible_cpu(i) {
 359                 memset((void *)critirq_ctx[i], 0, THREAD_SIZE);
 360                 tp = critirq_ctx[i];
 361                 tp->cpu = i;
 362                 tp->preempt_count = 0;
 363
 364 #ifdef CONFIG_BOOKE
 365                 memset((void *)dbgirq_ctx[i], 0, THREAD_SIZE);
 366                 tp = dbgirq_ctx[i];
 367                 tp->cpu = i;
 368                 tp->preempt_count = 0;
 369
 370                 memset((void *)mcheckirq_ctx[i], 0, THREAD_SIZE);
 371                 tp = mcheckirq_ctx[i];
 372                 tp->cpu = i;
 373                 tp->preempt_count = HARDIRQ_OFFSET;
 374 #endif
 375         }
 376 }
 377 #endif
 378
 379 #ifdef CONFIG_IRQSTACKS
 380 struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;
 381 struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly;
 382
 383 void irq_ctx_init(void)
 384 {
 385         struct thread_info *tp;
 386         int i;
 387
 388         for_each_possible_cpu(i) {
 389                 memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
 390                 tp = softirq_ctx[i];
 391                 tp->cpu = i;
 392                 tp->preempt_count = 0;
 393
 394                 memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
 395                 tp = hardirq_ctx[i];
 396                 tp->cpu = i;
 397                 tp->preempt_count = HARDIRQ_OFFSET;
 398         }
 399 }
 400
 401 static inline void do_softirq_onstack(void)
 402 {
 403         struct thread_info *curtp, *irqtp;
 404         unsigned long saved_sp_limit = current->thread.ksp_limit;
 405
 406         curtp = current_thread_info();
 407         irqtp = softirq_ctx[smp_processor_id()];
 408         irqtp->task = curtp->task;
 409         current->thread.ksp_limit = (unsigned long)irqtp +
 410                                     _ALIGN_UP(sizeof(struct thread_info), 16);
 411         call_do_softirq(irqtp);
 412         current->thread.ksp_limit = saved_sp_limit;
 413         irqtp->task = NULL;
 414 }
 415
 416 #else
 417 #define do_softirq_onstack()    __do_softirq()
 418 #endif /* CONFIG_IRQSTACKS */
 419
 420 void do_softirq(void)
 421 {
 422         unsigned long flags;
 423
 424         if (in_interrupt())
 425                 return;
 426
 427         local_irq_save(flags);
 428
 429         if (local_softirq_pending())
 430                 do_softirq_onstack();
 431
 432         local_irq_restore(flags);
 433 }
 434
 435
 436 /*
 437  * IRQ controller and virtual interrupts
 438  */
 439
 440 static LIST_HEAD(irq_hosts);
 441 static DEFINE_SPINLOCK(irq_big_lock);
 442 static unsigned int revmap_trees_allocated;
 443 static DEFINE_MUTEX(revmap_trees_mutex);
 444 struct irq_map_entry irq_map[NR_IRQS];
 445 static unsigned int irq_virq_count = NR_IRQS;
 446 static struct irq_host *irq_default_host;
 447
 448 irq_hw_number_t virq_to_hw(unsigned int virq)
 449 {
 450         return irq_map[virq].hwirq;
 451 }
 452 EXPORT_SYMBOL_GPL(virq_to_hw);
 453
 454 static int default_irq_host_match(struct irq_host *h, struct device_node *np)
 455 {
 456         return h->of_node != NULL && h->of_node == np;
 457 }
 458
 459 struct irq_host *irq_alloc_host(struct device_node *of_node,
 460                                 unsigned int revmap_type,
 461                                 unsigned int revmap_arg,
 462                                 struct irq_host_ops *ops,
 463                                 irq_hw_number_t inval_irq)
 464 {
 465         struct irq_host *host;
 466         unsigned int size = sizeof(struct irq_host);
 467         unsigned int i;
 468         unsigned int *rmap;
 469         unsigned long flags;
 470
 471         /* Allocate structure and revmap table if using linear mapping */
 472         if (revmap_type == IRQ_HOST_MAP_LINEAR)
 473                 size += revmap_arg * sizeof(unsigned int);
 474         host = zalloc_maybe_bootmem(size, GFP_KERNEL);
 475         if (host == NULL)
 476                 return NULL;
 477
 478         /* Fill structure */
 479         host->revmap_type = revmap_type;
 480         host->inval_irq = inval_irq;
 481         host->ops = ops;
 482         host->of_node = of_node_get(of_node);
 483
 484         if (host->ops->match == NULL)
 485                 host->ops->match = default_irq_host_match;
 486
 487         spin_lock_irqsave(&irq_big_lock, flags);
 488
 489         /* If it's a legacy controller, check for duplicates and
 490          * mark it as allocated (we use irq 0 host pointer for that
 491          */
 492         if (revmap_type == IRQ_HOST_MAP_LEGACY) {
 493                 if (irq_map[0].host != NULL) {
 494                         spin_unlock_irqrestore(&irq_big_lock, flags);
 495                         /* If we are early boot, we can't free the structure,
 496                          * too bad...
 497                          * this will be fixed once slab is made available early
 498                          * instead of the current cruft
 499                          */
 500                         if (mem_init_done)
 501                                 kfree(host);
 502                         return NULL;
 503                 }
 504                 irq_map[0].host = host;
 505         }
 506
 507         list_add(&host->link, &irq_hosts);
 508         spin_unlock_irqrestore(&irq_big_lock, flags);
 509
 510         /* Additional setups per revmap type */
 511         switch(revmap_type) {
 512         case IRQ_HOST_MAP_LEGACY:
 513                 /* 0 is always the invalid number for legacy */
 514                 host->inval_irq = 0;
 515                 /* setup us as the host for all legacy interrupts */
 516                 for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
 517                         irq_map[i].hwirq = i;
 518                         smp_wmb();
 519                         irq_map[i].host = host;
 520                         smp_wmb();
 521
 522                         /* Clear norequest flags */
 523                         get_irq_desc(i)->status &= ~IRQ_NOREQUEST;
 524
 525                         /* Legacy flags are left to default at this point,
 526                          * one can then use irq_create_mapping() to
 527                          * explicitly change them
 528                          */
 529                         ops->map(host, i, i);
 530                 }
 531                 break;
 532         case IRQ_HOST_MAP_LINEAR:
 533                 rmap = (unsigned int *)(host + 1);
 534                 for (i = 0; i < revmap_arg; i++)
 535                         rmap[i] = NO_IRQ;
 536                 host->revmap_data.linear.size = revmap_arg;
 537                 smp_wmb();
 538                 host->revmap_data.linear.revmap = rmap;
 539                 break;
 540         default:
 541                 break;
 542         }
 543
 544         pr_debug("irq: Allocated host of type %d @0x%p\n", revmap_type, host);
 545
 546         return host;
 547 }
 548
 549 struct irq_host *irq_find_host(struct device_node *node)
 550 {
 551         struct irq_host *h, *found = NULL;
 552         unsigned long flags;
 553
 554         /* We might want to match the legacy controller last since
 555          * it might potentially be set to match all interrupts in
 556          * the absence of a device node. This isn't a problem so far
 557          * yet though...
 558          */
 559         spin_lock_irqsave(&irq_big_lock, flags);
 560         list_for_each_entry(h, &irq_hosts, link)
 561                 if (h->ops->match(h, node)) {
 562                         found = h;
 563                         break;
 564                 }
 565         spin_unlock_irqrestore(&irq_big_lock, flags);
 566         return found;
 567 }
 568 EXPORT_SYMBOL_GPL(irq_find_host);
 569
 570 void irq_set_default_host(struct irq_host *host)
 571 {
 572         pr_debug("irq: Default host set to @0x%p\n", host);
 573
 574         irq_default_host = host;
 575 }
 576
 577 void irq_set_virq_count(unsigned int count)
 578 {
 579         pr_debug("irq: Trying to set virq count to %d\n", count);
 580
 581         BUG_ON(count < NUM_ISA_INTERRUPTS);
 582         if (count < NR_IRQS)
 583                 irq_virq_count = count;
 584 }
 585
 586 static int irq_setup_virq(struct irq_host *host, unsigned int virq,
 587                             irq_hw_number_t hwirq)
 588 {
 589         /* Clear IRQ_NOREQUEST flag */
 590         get_irq_desc(virq)->status &= ~IRQ_NOREQUEST;
 591
 592         /* map it */
 593         smp_wmb();
 594         irq_map[virq].hwirq = hwirq;
 595         smp_mb();
 596
 597         if (host->ops->map(host, virq, hwirq)) {
 598                 pr_debug("irq: -> mapping failed, freeing\n");
 599                 irq_free_virt(virq, 1);
 600                 return -1;
 601         }
 602
 603         return 0;
 604 }
 605
 606 unsigned int irq_create_direct_mapping(struct irq_host *host)
 607 {
 608         unsigned int virq;
 609
 610         if (host == NULL)
 611                 host = irq_default_host;
 612
 613         BUG_ON(host == NULL);
 614         WARN_ON(host->revmap_type != IRQ_HOST_MAP_NOMAP);
 615
 616         virq = irq_alloc_virt(host, 1, 0);
 617         if (virq == NO_IRQ) {
 618                 pr_debug("irq: create_direct virq allocation failed\n");
 619                 return NO_IRQ;
 620         }
 621
 622         pr_debug("irq: create_direct obtained virq %d\n", virq);
 623
 624         if (irq_setup_virq(host, virq, virq))
 625                 return NO_IRQ;
 626
 627         return virq;
 628 }
 629
 630 unsigned int irq_create_mapping(struct irq_host *host,
 631                                 irq_hw_number_t hwirq)
 632 {
 633         unsigned int virq, hint;
 634
 635         pr_debug("irq: irq_create_mapping(0x%p, 0x%lx)\n", host, hwirq);
 636
 637         /* Look for default host if nececssary */
 638         if (host == NULL)
 639                 host = irq_default_host;
 640         if (host == NULL) {
 641                 printk(KERN_WARNING "irq_create_mapping called for"
 642                        " NULL host, hwirq=%lx\n", hwirq);
 643                 WARN_ON(1);
 644                 return NO_IRQ;
 645         }
 646         pr_debug("irq: -> using host @%p\n", host);
 647
 648         /* Check if mapping already exist, if it does, call
 649          * host->ops->map() to update the flags
 650          */
 651         virq = irq_find_mapping(host, hwirq);
 652         if (virq != NO_IRQ) {
 653                 if (host->ops->remap)
 654                         host->ops->remap(host, virq, hwirq);
 655                 pr_debug("irq: -> existing mapping on virq %d\n", virq);
 656                 return virq;
 657         }
 658
 659         /* Get a virtual interrupt number */
 660         if (host->revmap_type == IRQ_HOST_MAP_LEGACY) {
 661                 /* Handle legacy */
 662                 virq = (unsigned int)hwirq;
 663                 if (virq == 0 || virq >= NUM_ISA_INTERRUPTS)
 664                         return NO_IRQ;
 665                 return virq;
 666         } else {
 667                 /* Allocate a virtual interrupt number */
 668                 hint = hwirq % irq_virq_count;
 669                 virq = irq_alloc_virt(host, 1, hint);
 670                 if (virq == NO_IRQ) {
 671                         pr_debug("irq: -> virq allocation failed\n");
 672                         return NO_IRQ;
 673                 }
 674         }
 675         pr_debug("irq: -> obtained virq %d\n", virq);
 676
 677         if (irq_setup_virq(host, virq, hwirq))
 678                 return NO_IRQ;
 679
 680         return virq;
 681 }
 682 EXPORT_SYMBOL_GPL(irq_create_mapping);
 683
 684 unsigned int irq_create_of_mapping(struct device_node *controller,
 685                                    u32 *intspec, unsigned int intsize)
 686 {
 687         struct irq_host *host;
 688         irq_hw_number_t hwirq;
 689         unsigned int type = IRQ_TYPE_NONE;
 690         unsigned int virq;
 691
 692         if (controller == NULL)
 693                 host = irq_default_host;
 694         else
 695                 host = irq_find_host(controller);
 696         if (host == NULL) {
 697                 printk(KERN_WARNING "irq: no irq host found for %s !\n",
 698                        controller->full_name);
 699                 return NO_IRQ;
 700         }
 701
 702         /* If host has no translation, then we assume interrupt line */
 703         if (host->ops->xlate == NULL)
 704                 hwirq = intspec[0];
 705         else {
 706                 if (host->ops->xlate(host, controller, intspec, intsize,
 707                                      &hwirq, &type))
 708                         return NO_IRQ;
 709         }
 710
 711         /* Create mapping */
 712         virq = irq_create_mapping(host, hwirq);
 713         if (virq == NO_IRQ)
 714                 return virq;
 715
 716         /* Set type if specified and different than the current one */
 717         if (type != IRQ_TYPE_NONE &&
 718             type != (get_irq_desc(virq)->status & IRQF_TRIGGER_MASK))
 719                 set_irq_type(virq, type);
 720         return virq;
 721 }
 722 EXPORT_SYMBOL_GPL(irq_create_of_mapping);
 723
 724 unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
 725 {
 726         struct of_irq oirq;
 727
 728         if (of_irq_map_one(dev, index, &oirq))
 729                 return NO_IRQ;
 730
 731         return irq_create_of_mapping(oirq.controller, oirq.specifier,
 732                                      oirq.size);
 733 }
 734 EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
 735
 736 void irq_dispose_mapping(unsigned int virq)
 737 {
 738         struct irq_host *host;
 739         irq_hw_number_t hwirq;
 740
 741         if (virq == NO_IRQ)
 742                 return;
 743
 744         host = irq_map[virq].host;
 745         WARN_ON (host == NULL);
 746         if (host == NULL)
 747                 return;
 748
 749         /* Never unmap legacy interrupts */
 750         if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
 751                 return;
 752
 753         /* remove chip and handler */
 754         set_irq_chip_and_handler(virq, NULL, NULL);
 755
 756         /* Make sure it's completed */
 757         synchronize_irq(virq);
 758
 759         /* Tell the PIC about it */
 760         if (host->ops->unmap)
 761                 host->ops->unmap(host, virq);
 762         smp_mb();
 763
 764         /* Clear reverse map */
 765         hwirq = irq_map[virq].hwirq;
 766         switch(host->revmap_type) {
 767         case IRQ_HOST_MAP_LINEAR:
 768                 if (hwirq < host->revmap_data.linear.size)
 769                         host->revmap_data.linear.revmap[hwirq] = NO_IRQ;
 770                 break;
 771         case IRQ_HOST_MAP_TREE:
 772                 /*
 773                  * Check if radix tree allocated yet, if not then nothing to
 774                  * remove.
 775                  */
 776                 smp_rmb();
 777                 if (revmap_trees_allocated < 1)
 778                         break;
 779                 mutex_lock(&revmap_trees_mutex);
 780                 radix_tree_delete(&host->revmap_data.tree, hwirq);
 781                 mutex_unlock(&revmap_trees_mutex);
 782                 break;
 783         }
 784
 785         /* Destroy map */
 786         smp_mb();
 787         irq_map[virq].hwirq = host->inval_irq;
 788
 789         /* Set some flags */
 790         get_irq_desc(virq)->status |= IRQ_NOREQUEST;
 791
 792         /* Free it */
 793         irq_free_virt(virq, 1);
 794 }
 795 EXPORT_SYMBOL_GPL(irq_dispose_mapping);
 796
 797 unsigned int irq_find_mapping(struct irq_host *host,
 798                               irq_hw_number_t hwirq)
 799 {
 800         unsigned int i;
 801         unsigned int hint = hwirq % irq_virq_count;
 802
 803         /* Look for default host if nececssary */
 804         if (host == NULL)
 805                 host = irq_default_host;
 806         if (host == NULL)
 807                 return NO_IRQ;
 808
 809         /* legacy -> bail early */
 810         if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
 811                 return hwirq;
 812
 813         /* Slow path does a linear search of the map */
 814         if (hint < NUM_ISA_INTERRUPTS)
 815                 hint = NUM_ISA_INTERRUPTS;
 816         i = hint;
 817         do  {
 818                 if (irq_map[i].host == host &&
 819                     irq_map[i].hwirq == hwirq)
 820                         return i;
 821                 i++;
 822                 if (i >= irq_virq_count)
 823                         i = NUM_ISA_INTERRUPTS;
 824         } while(i != hint);
 825         return NO_IRQ;
 826 }
 827 EXPORT_SYMBOL_GPL(irq_find_mapping);
 828
 829
 830 unsigned int irq_radix_revmap_lookup(struct irq_host *host,
 831                                      irq_hw_number_t hwirq)
 832 {
 833         struct irq_map_entry *ptr;
 834         unsigned int virq;
 835
 836         WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);
 837
 838         /*
 839          * Check if the radix tree exists and has bee initialized.
 840          * If not, we fallback to slow mode
 841          */
 842         if (revmap_trees_allocated < 2)
 843                 return irq_find_mapping(host, hwirq);
 844
 845         /* Now try to resolve */
 846         /*
 847          * No rcu_read_lock(ing) needed, the ptr returned can't go under us
 848          * as it's referencing an entry in the static irq_map table.
 849          */
 850         ptr = radix_tree_lookup(&host->revmap_data.tree, hwirq);
 851
 852         /*
 853          * If found in radix tree, then fine.
 854          * Else fallback to linear lookup - this should not happen in practice
 855          * as it means that we failed to insert the node in the radix tree.
 856          */
 857         if (ptr)
 858                 virq = ptr - irq_map;
 859         else
 860                 virq = irq_find_mapping(host, hwirq);
 861
 862         return virq;
 863 }
 864
 865 void irq_radix_revmap_insert(struct irq_host *host, unsigned int virq,
 866                              irq_hw_number_t hwirq)
 867 {
 868
 869         WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);
 870
 871         /*
 872          * Check if the radix tree exists yet.
 873          * If not, then the irq will be inserted into the tree when it gets
 874          * initialized.
 875          */
 876         smp_rmb();
 877         if (revmap_trees_allocated < 1)
 878                 return;
 879
 880         if (virq != NO_IRQ) {
 881                 mutex_lock(&revmap_trees_mutex);
 882                 radix_tree_insert(&host->revmap_data.tree, hwirq,
 883                                   &irq_map[virq]);
 884                 mutex_unlock(&revmap_trees_mutex);
 885         }
 886 }
 887
 888 unsigned int irq_linear_revmap(struct irq_host *host,
 889                                irq_hw_number_t hwirq)
 890 {
 891         unsigned int *revmap;
 892
 893         WARN_ON(host->revmap_type != IRQ_HOST_MAP_LINEAR);
 894
 895         /* Check revmap bounds */
 896         if (unlikely(hwirq >= host->revmap_data.linear.size))
 897                 return irq_find_mapping(host, hwirq);
 898
 899         /* Check if revmap was allocated */
 900         revmap = host->revmap_data.linear.revmap;
 901         if (unlikely(revmap == NULL))
 902                 return irq_find_mapping(host, hwirq);
 903
 904         /* Fill up revmap with slow path if no mapping found */
 905         if (unlikely(revmap[hwirq] == NO_IRQ))
 906                 revmap[hwirq] = irq_find_mapping(host, hwirq);
 907
 908         return revmap[hwirq];
 909 }
 910
 911 unsigned int irq_alloc_virt(struct irq_host *host,
 912                             unsigned int count,
 913                             unsigned int hint)
 914 {
 915         unsigned long flags;
 916         unsigned int i, j, found = NO_IRQ;
 917
 918         if (count == 0 || count > (irq_virq_count - NUM_ISA_INTERRUPTS))
 919                 return NO_IRQ;
 920
 921         spin_lock_irqsave(&irq_big_lock, flags);
 922
 923         /* Use hint for 1 interrupt if any */
 924         if (count == 1 && hint >= NUM_ISA_INTERRUPTS &&
 925             hint < irq_virq_count && irq_map[hint].host == NULL) {
 926                 found = hint;
 927                 goto hint_found;
 928         }
 929
 930         /* Look for count consecutive numbers in the allocatable
 931          * (non-legacy) space
 932          */
 933         for (i = NUM_ISA_INTERRUPTS, j = 0; i < irq_virq_count; i++) {
 934                 if (irq_map[i].host != NULL)
 935                         j = 0;
 936                 else
 937                         j++;
 938
 939                 if (j == count) {
 940                         found = i - count + 1;
 941                         break;
 942                 }
 943         }
 944         if (found == NO_IRQ) {
 945                 spin_unlock_irqrestore(&irq_big_lock, flags);
 946                 return NO_IRQ;
 947         }
 948  hint_found:
 949         for (i = found; i < (found + count); i++) {
 950                 irq_map[i].hwirq = host->inval_irq;
 951                 smp_wmb();
 952                 irq_map[i].host = host;
 953         }
 954         spin_unlock_irqrestore(&irq_big_lock, flags);
 955         return found;
 956 }
 957
 958 void irq_free_virt(unsigned int virq, unsigned int count)
 959 {
 960         unsigned long flags;
 961         unsigned int i;
 962
 963         WARN_ON (virq < NUM_ISA_INTERRUPTS);
 964         WARN_ON (count == 0 || (virq + count) > irq_virq_count);
 965
 966         spin_lock_irqsave(&irq_big_lock, flags);
 967         for (i = virq; i < (virq + count); i++) {
 968                 struct irq_host *host;
 969
 970                 if (i < NUM_ISA_INTERRUPTS ||
 971                     (virq + count) > irq_virq_count)
 972                         continue;
 973
 974                 host = irq_map[i].host;
 975                 irq_map[i].hwirq = host->inval_irq;
 976                 smp_wmb();
 977                 irq_map[i].host = NULL;
 978         }
 979         spin_unlock_irqrestore(&irq_big_lock, flags);
 980 }
 981
 982 void irq_early_init(void)
 983 {
 984         unsigned int i;
 985
 986         for (i = 0; i < NR_IRQS; i++)
 987                 get_irq_desc(i)->status |= IRQ_NOREQUEST;
 988 }
 989
 990 /* We need to create the radix trees late */
 991 static int irq_late_init(void)
 992 {
 993         struct irq_host *h;
 994         unsigned int i;
 995
 996         /*
 997          * No mutual exclusion with respect to accessors of the tree is needed
 998          * here as the synchronization is done via the state variable
 999          * revmap_trees_allocated.
1000          */
1001         list_for_each_entry(h, &irq_hosts, link) {
1002                 if (h->revmap_type == IRQ_HOST_MAP_TREE)
1003                         INIT_RADIX_TREE(&h->revmap_data.tree, GFP_KERNEL);
1004         }
1005
1006         /*
1007          * Make sure the radix trees inits are visible before setting
1008          * the flag
1009          */
1010         smp_wmb();
1011         revmap_trees_allocated = 1;
1012
1013         /*
1014          * Insert the reverse mapping for those interrupts already present
1015          * in irq_map[].
1016          */
1017         mutex_lock(&revmap_trees_mutex);
1018         for (i = 0; i < irq_virq_count; i++) {
1019                 if (irq_map[i].host &&
1020                     (irq_map[i].host->revmap_type == IRQ_HOST_MAP_TREE))
1021                         radix_tree_insert(&irq_map[i].host->revmap_data.tree,
1022                                           irq_map[i].hwirq, &irq_map[i]);
1023         }
1024         mutex_unlock(&revmap_trees_mutex);
1025
1026         /*
1027          * Make sure the radix trees insertions are visible before setting
1028          * the flag
1029          */
1030         smp_wmb();
1031         revmap_trees_allocated = 2;
1032
1033         return 0;
1034 }
1035 arch_initcall(irq_late_init);
1036
1037 #ifdef CONFIG_VIRQ_DEBUG
1038 static int virq_debug_show(struct seq_file *m, void *private)
1039 {
1040         unsigned long flags;
1041         struct irq_desc *desc;
1042         const char *p;
1043         char none[] = "none";
1044         int i;
1045
1046         seq_printf(m, "%-5s  %-7s  %-15s  %s\n", "virq", "hwirq",
1047                       "chip name", "host name");
1048
1049         for (i = 1; i < NR_IRQS; i++) {
1050                 desc = get_irq_desc(i);
1051                 spin_lock_irqsave(&desc->lock, flags);
1052
1053                 if (desc->action && desc->action->handler) {
1054                         seq_printf(m, "%5d  ", i);
1055                         seq_printf(m, "0x%05lx  ", virq_to_hw(i));
1056
1057                         if (desc->chip && desc->chip->typename)
1058                                 p = desc->chip->typename;
1059                         else
1060                                 p = none;
1061                         seq_printf(m, "%-15s  ", p);
1062
1063                         if (irq_map[i].host && irq_map[i].host->of_node)
1064                                 p = irq_map[i].host->of_node->full_name;
1065                         else
1066                                 p = none;
1067                         seq_printf(m, "%s\n", p);
1068                 }
1069
1070                 spin_unlock_irqrestore(&desc->lock, flags);
1071         }
1072
1073         return 0;
1074 }
1075
1076 static int virq_debug_open(struct inode *inode, struct file *file)
1077 {
1078         return single_open(file, virq_debug_show, inode->i_private);
1079 }
1080
1081 static const struct file_operations virq_debug_fops = {
1082         .open = virq_debug_open,
1083         .read = seq_read,
1084         .llseek = seq_lseek,
1085         .release = single_release,
1086 };
1087
1088 static int __init irq_debugfs_init(void)
1089 {
1090         if (debugfs_create_file("virq_mapping", S_IRUGO, powerpc_debugfs_root,
1091                                  NULL, &virq_debug_fops) == NULL)
1092                 return -ENOMEM;
1093
1094         return 0;
1095 }
1096 __initcall(irq_debugfs_init);
1097 #endif /* CONFIG_VIRQ_DEBUG */
1098
1099 #ifdef CONFIG_PPC64
1100 static int __init setup_noirqdistrib(char *str)
1101 {
1102         distribute_irqs = 0;
1103         return 1;
1104 }
1105
1106 __setup("noirqdistrib", setup_noirqdistrib);
1107 #endif /* CONFIG_PPC64 */