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
  56 #include <asm/uaccess.h>
  57 #include <asm/system.h>
  58 #include <asm/io.h>
  59 #include <asm/pgtable.h>
  60 #include <asm/irq.h>
  61 #include <asm/cache.h>
  62 #include <asm/prom.h>
  63 #include <asm/ptrace.h>
  64 #include <asm/machdep.h>
  65 #include <asm/udbg.h>
  66 #ifdef CONFIG_PPC64
  67 #include <asm/paca.h>
  68 #include <asm/firmware.h>
  69 #include <asm/lv1call.h>
  70 #endif
  71
  72 int __irq_offset_value;
  73 static int ppc_spurious_interrupts;
  74
  75 #ifdef CONFIG_PPC32
  76 EXPORT_SYMBOL(__irq_offset_value);
  77 atomic_t ppc_n_lost_interrupts;
  78
  79 #ifndef CONFIG_PPC_MERGE
  80 #define NR_MASK_WORDS   ((NR_IRQS + 31) / 32)
  81 unsigned long ppc_cached_irq_mask[NR_MASK_WORDS];
  82 #endif
  83
  84 #ifdef CONFIG_TAU_INT
  85 extern int tau_initialized;
  86 extern int tau_interrupts(int);
  87 #endif
  88 #endif /* CONFIG_PPC32 */
  89
  90 #if defined(CONFIG_SMP) && !defined(CONFIG_PPC_MERGE)
  91 extern atomic_t ipi_recv;
  92 extern atomic_t ipi_sent;
  93 #endif
  94
  95 #ifdef CONFIG_PPC64
  96 EXPORT_SYMBOL(irq_desc);
  97
  98 int distribute_irqs = 1;
  99
 100 static inline unsigned long get_hard_enabled(void)
 101 {
 102         unsigned long enabled;
 103
 104         __asm__ __volatile__("lbz %0,%1(13)"
 105         : "=r" (enabled) : "i" (offsetof(struct paca_struct, hard_enabled)));
 106
 107         return enabled;
 108 }
 109
 110 static inline void set_soft_enabled(unsigned long enable)
 111 {
 112         __asm__ __volatile__("stb %0,%1(13)"
 113         : : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
 114 }
 115
 116 void local_irq_restore(unsigned long en)
 117 {
 118         /*
 119          * get_paca()->soft_enabled = en;
 120          * Is it ever valid to use local_irq_restore(0) when soft_enabled is 1?
 121          * That was allowed before, and in such a case we do need to take care
 122          * that gcc will set soft_enabled directly via r13, not choose to use
 123          * an intermediate register, lest we're preempted to a different cpu.
 124          */
 125         set_soft_enabled(en);
 126         if (!en)
 127                 return;
 128
 129         if (firmware_has_feature(FW_FEATURE_ISERIES)) {
 130                 /*
 131                  * Do we need to disable preemption here?  Not really: in the
 132                  * unlikely event that we're preempted to a different cpu in
 133                  * between getting r13, loading its lppaca_ptr, and loading
 134                  * its any_int, we might call iseries_handle_interrupts without
 135                  * an interrupt pending on the new cpu, but that's no disaster,
 136                  * is it?  And the business of preempting us off the old cpu
 137                  * would itself involve a local_irq_restore which handles the
 138                  * interrupt to that cpu.
 139                  *
 140                  * But use "local_paca->lppaca_ptr" instead of "get_lppaca()"
 141                  * to avoid any preemption checking added into get_paca().
 142                  */
 143                 if (local_paca->lppaca_ptr->int_dword.any_int)
 144                         iseries_handle_interrupts();
 145                 return;
 146         }
 147
 148         /*
 149          * if (get_paca()->hard_enabled) return;
 150          * But again we need to take care that gcc gets hard_enabled directly
 151          * via r13, not choose to use an intermediate register, lest we're
 152          * preempted to a different cpu in between the two instructions.
 153          */
 154         if (get_hard_enabled())
 155                 return;
 156
 157         /*
 158          * Need to hard-enable interrupts here.  Since currently disabled,
 159          * no need to take further asm precautions against preemption; but
 160          * use local_paca instead of get_paca() to avoid preemption checking.
 161          */
 162         local_paca->hard_enabled = en;
 163         if ((int)mfspr(SPRN_DEC) < 0)
 164                 mtspr(SPRN_DEC, 1);
 165
 166         /*
 167          * Force the delivery of pending soft-disabled interrupts on PS3.
 168          * Any HV call will have this side effect.
 169          */
 170         if (firmware_has_feature(FW_FEATURE_PS3_LV1)) {
 171                 u64 tmp;
 172                 lv1_get_version_info(&tmp);
 173         }
 174
 175         __hard_irq_enable();
 176 }
 177 #endif /* CONFIG_PPC64 */
 178
 179 int show_interrupts(struct seq_file *p, void *v)
 180 {
 181         int i = *(loff_t *)v, j;
 182         struct irqaction *action;
 183         irq_desc_t *desc;
 184         unsigned long flags;
 185
 186         if (i == 0) {
 187                 seq_puts(p, "           ");
 188                 for_each_online_cpu(j)
 189                         seq_printf(p, "CPU%d       ", j);
 190                 seq_putc(p, '\n');
 191         }
 192
 193         if (i < NR_IRQS) {
 194                 desc = get_irq_desc(i);
 195                 spin_lock_irqsave(&desc->lock, flags);
 196                 action = desc->action;
 197                 if (!action || !action->handler)
 198                         goto skip;
 199                 seq_printf(p, "%3d: ", i);
 200 #ifdef CONFIG_SMP
 201                 for_each_online_cpu(j)
 202                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 203 #else
 204                 seq_printf(p, "%10u ", kstat_irqs(i));
 205 #endif /* CONFIG_SMP */
 206                 if (desc->chip)
 207                         seq_printf(p, " %s ", desc->chip->typename);
 208                 else
 209                         seq_puts(p, "  None      ");
 210                 seq_printf(p, "%s", (desc->status & IRQ_LEVEL) ? "Level " : "Edge  ");
 211                 seq_printf(p, "    %s", action->name);
 212                 for (action = action->next; action; action = action->next)
 213                         seq_printf(p, ", %s", action->name);
 214                 seq_putc(p, '\n');
 215 skip:
 216                 spin_unlock_irqrestore(&desc->lock, flags);
 217         } else if (i == NR_IRQS) {
 218 #ifdef CONFIG_PPC32
 219 #ifdef CONFIG_TAU_INT
 220                 if (tau_initialized){
 221                         seq_puts(p, "TAU: ");
 222                         for_each_online_cpu(j)
 223                                 seq_printf(p, "%10u ", tau_interrupts(j));
 224                         seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
 225                 }
 226 #endif
 227 #if defined(CONFIG_SMP) && !defined(CONFIG_PPC_MERGE)
 228                 /* should this be per processor send/receive? */
 229                 seq_printf(p, "IPI (recv/sent): %10u/%u\n",
 230                                 atomic_read(&ipi_recv), atomic_read(&ipi_sent));
 231 #endif
 232 #endif /* CONFIG_PPC32 */
 233                 seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
 234         }
 235         return 0;
 236 }
 237
 238 #ifdef CONFIG_HOTPLUG_CPU
 239 void fixup_irqs(cpumask_t map)
 240 {
 241         unsigned int irq;
 242         static int warned;
 243
 244         for_each_irq(irq) {
 245                 cpumask_t mask;
 246
 247                 if (irq_desc[irq].status & IRQ_PER_CPU)
 248                         continue;
 249
 250                 cpus_and(mask, irq_desc[irq].affinity, map);
 251                 if (any_online_cpu(mask) == NR_CPUS) {
 252                         printk("Breaking affinity for irq %i\n", irq);
 253                         mask = map;
 254                 }
 255                 if (irq_desc[irq].chip->set_affinity)
 256                         irq_desc[irq].chip->set_affinity(irq, mask);
 257                 else if (irq_desc[irq].action && !(warned++))
 258                         printk("Cannot set affinity for irq %i\n", irq);
 259         }
 260
 261         local_irq_enable();
 262         mdelay(1);
 263         local_irq_disable();
 264 }
 265 #endif
 266
 267 void do_IRQ(struct pt_regs *regs)
 268 {
 269         struct pt_regs *old_regs = set_irq_regs(regs);
 270         unsigned int irq;
 271 #ifdef CONFIG_IRQSTACKS
 272         struct thread_info *curtp, *irqtp;
 273 #endif
 274
 275         irq_enter();
 276
 277 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 278         /* Debugging check for stack overflow: is there less than 2KB free? */
 279         {
 280                 long sp;
 281
 282                 sp = __get_SP() & (THREAD_SIZE-1);
 283
 284                 if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
 285                         printk("do_IRQ: stack overflow: %ld\n",
 286                                 sp - sizeof(struct thread_info));
 287                         dump_stack();
 288                 }
 289         }
 290 #endif
 291
 292         /*
 293          * Every platform is required to implement ppc_md.get_irq.
 294          * This function will either return an irq number or NO_IRQ to
 295          * indicate there are no more pending.
 296          * The value NO_IRQ_IGNORE is for buggy hardware and means that this
 297          * IRQ has already been handled. -- Tom
 298          */
 299         irq = ppc_md.get_irq();
 300
 301         if (irq != NO_IRQ && irq != NO_IRQ_IGNORE) {
 302 #ifdef CONFIG_IRQSTACKS
 303                 /* Switch to the irq stack to handle this */
 304                 curtp = current_thread_info();
 305                 irqtp = hardirq_ctx[smp_processor_id()];
 306                 if (curtp != irqtp) {
 307                         struct irq_desc *desc = irq_desc + irq;
 308                         void *handler = desc->handle_irq;
 309                         if (handler == NULL)
 310                                 handler = &__do_IRQ;
 311                         irqtp->task = curtp->task;
 312                         irqtp->flags = 0;
 313                         call_handle_irq(irq, desc, irqtp, handler);
 314                         irqtp->task = NULL;
 315                         if (irqtp->flags)
 316                                 set_bits(irqtp->flags, &curtp->flags);
 317                 } else
 318 #endif
 319                         generic_handle_irq(irq);
 320         } else if (irq != NO_IRQ_IGNORE)
 321                 /* That's not SMP safe ... but who cares ? */
 322                 ppc_spurious_interrupts++;
 323
 324         irq_exit();
 325         set_irq_regs(old_regs);
 326
 327 #ifdef CONFIG_PPC_ISERIES
 328         if (firmware_has_feature(FW_FEATURE_ISERIES) &&
 329                         get_lppaca()->int_dword.fields.decr_int) {
 330                 get_lppaca()->int_dword.fields.decr_int = 0;
 331                 /* Signal a fake decrementer interrupt */
 332                 timer_interrupt(regs);
 333         }
 334 #endif
 335 }
 336
 337 void __init init_IRQ(void)
 338 {
 339         if (ppc_md.init_IRQ)
 340                 ppc_md.init_IRQ();
 341 #ifdef CONFIG_PPC64
 342         irq_ctx_init();
 343 #endif
 344 }
 345
 346
 347 #ifdef CONFIG_IRQSTACKS
 348 struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;
 349 struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly;
 350
 351 void irq_ctx_init(void)
 352 {
 353         struct thread_info *tp;
 354         int i;
 355
 356         for_each_possible_cpu(i) {
 357                 memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
 358                 tp = softirq_ctx[i];
 359                 tp->cpu = i;
 360                 tp->preempt_count = SOFTIRQ_OFFSET;
 361
 362                 memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
 363                 tp = hardirq_ctx[i];
 364                 tp->cpu = i;
 365                 tp->preempt_count = HARDIRQ_OFFSET;
 366         }
 367 }
 368
 369 static inline void do_softirq_onstack(void)
 370 {
 371         struct thread_info *curtp, *irqtp;
 372
 373         curtp = current_thread_info();
 374         irqtp = softirq_ctx[smp_processor_id()];
 375         irqtp->task = curtp->task;
 376         call_do_softirq(irqtp);
 377         irqtp->task = NULL;
 378 }
 379
 380 #else
 381 #define do_softirq_onstack()    __do_softirq()
 382 #endif /* CONFIG_IRQSTACKS */
 383
 384 void do_softirq(void)
 385 {
 386         unsigned long flags;
 387
 388         if (in_interrupt())
 389                 return;
 390
 391         local_irq_save(flags);
 392
 393         if (local_softirq_pending())
 394                 do_softirq_onstack();
 395
 396         local_irq_restore(flags);
 397 }
 398
 399
 400 /*
 401  * IRQ controller and virtual interrupts
 402  */
 403
 404 #ifdef CONFIG_PPC_MERGE
 405
 406 static LIST_HEAD(irq_hosts);
 407 static DEFINE_SPINLOCK(irq_big_lock);
 408 static DEFINE_PER_CPU(unsigned int, irq_radix_reader);
 409 static unsigned int irq_radix_writer;
 410 struct irq_map_entry irq_map[NR_IRQS];
 411 static unsigned int irq_virq_count = NR_IRQS;
 412 static struct irq_host *irq_default_host;
 413
 414 irq_hw_number_t virq_to_hw(unsigned int virq)
 415 {
 416         return irq_map[virq].hwirq;
 417 }
 418 EXPORT_SYMBOL_GPL(virq_to_hw);
 419
 420 __init_refok struct irq_host *irq_alloc_host(unsigned int revmap_type,
 421                                                 unsigned int revmap_arg,
 422                                                 struct irq_host_ops *ops,
 423                                                 irq_hw_number_t inval_irq)
 424 {
 425         struct irq_host *host;
 426         unsigned int size = sizeof(struct irq_host);
 427         unsigned int i;
 428         unsigned int *rmap;
 429         unsigned long flags;
 430
 431         /* Allocate structure and revmap table if using linear mapping */
 432         if (revmap_type == IRQ_HOST_MAP_LINEAR)
 433                 size += revmap_arg * sizeof(unsigned int);
 434         if (mem_init_done)
 435                 host = kzalloc(size, GFP_KERNEL);
 436         else {
 437                 host = alloc_bootmem(size);
 438                 if (host)
 439                         memset(host, 0, size);
 440         }
 441         if (host == NULL)
 442                 return NULL;
 443
 444         /* Fill structure */
 445         host->revmap_type = revmap_type;
 446         host->inval_irq = inval_irq;
 447         host->ops = ops;
 448
 449         spin_lock_irqsave(&irq_big_lock, flags);
 450
 451         /* If it's a legacy controller, check for duplicates and
 452          * mark it as allocated (we use irq 0 host pointer for that
 453          */
 454         if (revmap_type == IRQ_HOST_MAP_LEGACY) {
 455                 if (irq_map[0].host != NULL) {
 456                         spin_unlock_irqrestore(&irq_big_lock, flags);
 457                         /* If we are early boot, we can't free the structure,
 458                          * too bad...
 459                          * this will be fixed once slab is made available early
 460                          * instead of the current cruft
 461                          */
 462                         if (mem_init_done)
 463                                 kfree(host);
 464                         return NULL;
 465                 }
 466                 irq_map[0].host = host;
 467         }
 468
 469         list_add(&host->link, &irq_hosts);
 470         spin_unlock_irqrestore(&irq_big_lock, flags);
 471
 472         /* Additional setups per revmap type */
 473         switch(revmap_type) {
 474         case IRQ_HOST_MAP_LEGACY:
 475                 /* 0 is always the invalid number for legacy */
 476                 host->inval_irq = 0;
 477                 /* setup us as the host for all legacy interrupts */
 478                 for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
 479                         irq_map[i].hwirq = 0;
 480                         smp_wmb();
 481                         irq_map[i].host = host;
 482                         smp_wmb();
 483
 484                         /* Clear norequest flags */
 485                         get_irq_desc(i)->status &= ~IRQ_NOREQUEST;
 486
 487                         /* Legacy flags are left to default at this point,
 488                          * one can then use irq_create_mapping() to
 489                          * explicitely change them
 490                          */
 491                         ops->map(host, i, i);
 492                 }
 493                 break;
 494         case IRQ_HOST_MAP_LINEAR:
 495                 rmap = (unsigned int *)(host + 1);
 496                 for (i = 0; i < revmap_arg; i++)
 497                         rmap[i] = NO_IRQ;
 498                 host->revmap_data.linear.size = revmap_arg;
 499                 smp_wmb();
 500                 host->revmap_data.linear.revmap = rmap;
 501                 break;
 502         default:
 503                 break;
 504         }
 505
 506         pr_debug("irq: Allocated host of type %d @0x%p\n", revmap_type, host);
 507
 508         return host;
 509 }
 510
 511 struct irq_host *irq_find_host(struct device_node *node)
 512 {
 513         struct irq_host *h, *found = NULL;
 514         unsigned long flags;
 515
 516         /* We might want to match the legacy controller last since
 517          * it might potentially be set to match all interrupts in
 518          * the absence of a device node. This isn't a problem so far
 519          * yet though...
 520          */
 521         spin_lock_irqsave(&irq_big_lock, flags);
 522         list_for_each_entry(h, &irq_hosts, link)
 523                 if (h->ops->match == NULL || h->ops->match(h, node)) {
 524                         found = h;
 525                         break;
 526                 }
 527         spin_unlock_irqrestore(&irq_big_lock, flags);
 528         return found;
 529 }
 530 EXPORT_SYMBOL_GPL(irq_find_host);
 531
 532 void irq_set_default_host(struct irq_host *host)
 533 {
 534         pr_debug("irq: Default host set to @0x%p\n", host);
 535
 536         irq_default_host = host;
 537 }
 538
 539 void irq_set_virq_count(unsigned int count)
 540 {
 541         pr_debug("irq: Trying to set virq count to %d\n", count);
 542
 543         BUG_ON(count < NUM_ISA_INTERRUPTS);
 544         if (count < NR_IRQS)
 545                 irq_virq_count = count;
 546 }
 547
 548 /* radix tree not lockless safe ! we use a brlock-type mecanism
 549  * for now, until we can use a lockless radix tree
 550  */
 551 static void irq_radix_wrlock(unsigned long *flags)
 552 {
 553         unsigned int cpu, ok;
 554
 555         spin_lock_irqsave(&irq_big_lock, *flags);
 556         irq_radix_writer = 1;
 557         smp_mb();
 558         do {
 559                 barrier();
 560                 ok = 1;
 561                 for_each_possible_cpu(cpu) {
 562                         if (per_cpu(irq_radix_reader, cpu)) {
 563                                 ok = 0;
 564                                 break;
 565                         }
 566                 }
 567                 if (!ok)
 568                         cpu_relax();
 569         } while(!ok);
 570 }
 571
 572 static void irq_radix_wrunlock(unsigned long flags)
 573 {
 574         smp_wmb();
 575         irq_radix_writer = 0;
 576         spin_unlock_irqrestore(&irq_big_lock, flags);
 577 }
 578
 579 static void irq_radix_rdlock(unsigned long *flags)
 580 {
 581         local_irq_save(*flags);
 582         __get_cpu_var(irq_radix_reader) = 1;
 583         smp_mb();
 584         if (likely(irq_radix_writer == 0))
 585                 return;
 586         __get_cpu_var(irq_radix_reader) = 0;
 587         smp_wmb();
 588         spin_lock(&irq_big_lock);
 589         __get_cpu_var(irq_radix_reader) = 1;
 590         spin_unlock(&irq_big_lock);
 591 }
 592
 593 static void irq_radix_rdunlock(unsigned long flags)
 594 {
 595         __get_cpu_var(irq_radix_reader) = 0;
 596         local_irq_restore(flags);
 597 }
 598
 599 static int irq_setup_virq(struct irq_host *host, unsigned int virq,
 600                             irq_hw_number_t hwirq)
 601 {
 602         /* Clear IRQ_NOREQUEST flag */
 603         get_irq_desc(virq)->status &= ~IRQ_NOREQUEST;
 604
 605         /* map it */
 606         smp_wmb();
 607         irq_map[virq].hwirq = hwirq;
 608         smp_mb();
 609
 610         if (host->ops->map(host, virq, hwirq)) {
 611                 pr_debug("irq: -> mapping failed, freeing\n");
 612                 irq_free_virt(virq, 1);
 613                 return -1;
 614         }
 615
 616         return 0;
 617 }
 618
 619 unsigned int irq_create_direct_mapping(struct irq_host *host)
 620 {
 621         unsigned int virq;
 622
 623         if (host == NULL)
 624                 host = irq_default_host;
 625
 626         BUG_ON(host == NULL);
 627         WARN_ON(host->revmap_type != IRQ_HOST_MAP_NOMAP);
 628
 629         virq = irq_alloc_virt(host, 1, 0);
 630         if (virq == NO_IRQ) {
 631                 pr_debug("irq: create_direct virq allocation failed\n");
 632                 return NO_IRQ;
 633         }
 634
 635         pr_debug("irq: create_direct obtained virq %d\n", virq);
 636
 637         if (irq_setup_virq(host, virq, virq))
 638                 return NO_IRQ;
 639
 640         return virq;
 641 }
 642
 643 unsigned int irq_create_mapping(struct irq_host *host,
 644                                 irq_hw_number_t hwirq)
 645 {
 646         unsigned int virq, hint;
 647
 648         pr_debug("irq: irq_create_mapping(0x%p, 0x%lx)\n", host, hwirq);
 649
 650         /* Look for default host if nececssary */
 651         if (host == NULL)
 652                 host = irq_default_host;
 653         if (host == NULL) {
 654                 printk(KERN_WARNING "irq_create_mapping called for"
 655                        " NULL host, hwirq=%lx\n", hwirq);
 656                 WARN_ON(1);
 657                 return NO_IRQ;
 658         }
 659         pr_debug("irq: -> using host @%p\n", host);
 660
 661         /* Check if mapping already exist, if it does, call
 662          * host->ops->map() to update the flags
 663          */
 664         virq = irq_find_mapping(host, hwirq);
 665         if (virq != NO_IRQ) {
 666                 if (host->ops->remap)
 667                         host->ops->remap(host, virq, hwirq);
 668                 pr_debug("irq: -> existing mapping on virq %d\n", virq);
 669                 return virq;
 670         }
 671
 672         /* Get a virtual interrupt number */
 673         if (host->revmap_type == IRQ_HOST_MAP_LEGACY) {
 674                 /* Handle legacy */
 675                 virq = (unsigned int)hwirq;
 676                 if (virq == 0 || virq >= NUM_ISA_INTERRUPTS)
 677                         return NO_IRQ;
 678                 return virq;
 679         } else {
 680                 /* Allocate a virtual interrupt number */
 681                 hint = hwirq % irq_virq_count;
 682                 virq = irq_alloc_virt(host, 1, hint);
 683                 if (virq == NO_IRQ) {
 684                         pr_debug("irq: -> virq allocation failed\n");
 685                         return NO_IRQ;
 686                 }
 687         }
 688         pr_debug("irq: -> obtained virq %d\n", virq);
 689
 690         if (irq_setup_virq(host, virq, hwirq))
 691                 return NO_IRQ;
 692
 693         return virq;
 694 }
 695 EXPORT_SYMBOL_GPL(irq_create_mapping);
 696
 697 unsigned int irq_create_of_mapping(struct device_node *controller,
 698                                    u32 *intspec, unsigned int intsize)
 699 {
 700         struct irq_host *host;
 701         irq_hw_number_t hwirq;
 702         unsigned int type = IRQ_TYPE_NONE;
 703         unsigned int virq;
 704
 705         if (controller == NULL)
 706                 host = irq_default_host;
 707         else
 708                 host = irq_find_host(controller);
 709         if (host == NULL) {
 710                 printk(KERN_WARNING "irq: no irq host found for %s !\n",
 711                        controller->full_name);
 712                 return NO_IRQ;
 713         }
 714
 715         /* If host has no translation, then we assume interrupt line */
 716         if (host->ops->xlate == NULL)
 717                 hwirq = intspec[0];
 718         else {
 719                 if (host->ops->xlate(host, controller, intspec, intsize,
 720                                      &hwirq, &type))
 721                         return NO_IRQ;
 722         }
 723
 724         /* Create mapping */
 725         virq = irq_create_mapping(host, hwirq);
 726         if (virq == NO_IRQ)
 727                 return virq;
 728
 729         /* Set type if specified and different than the current one */
 730         if (type != IRQ_TYPE_NONE &&
 731             type != (get_irq_desc(virq)->status & IRQF_TRIGGER_MASK))
 732                 set_irq_type(virq, type);
 733         return virq;
 734 }
 735 EXPORT_SYMBOL_GPL(irq_create_of_mapping);
 736
 737 unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
 738 {
 739         struct of_irq oirq;
 740
 741         if (of_irq_map_one(dev, index, &oirq))
 742                 return NO_IRQ;
 743
 744         return irq_create_of_mapping(oirq.controller, oirq.specifier,
 745                                      oirq.size);
 746 }
 747 EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
 748
 749 void irq_dispose_mapping(unsigned int virq)
 750 {
 751         struct irq_host *host;
 752         irq_hw_number_t hwirq;
 753         unsigned long flags;
 754
 755         if (virq == NO_IRQ)
 756                 return;
 757
 758         host = irq_map[virq].host;
 759         WARN_ON (host == NULL);
 760         if (host == NULL)
 761                 return;
 762
 763         /* Never unmap legacy interrupts */
 764         if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
 765                 return;
 766
 767         /* remove chip and handler */
 768         set_irq_chip_and_handler(virq, NULL, NULL);
 769
 770         /* Make sure it's completed */
 771         synchronize_irq(virq);
 772
 773         /* Tell the PIC about it */
 774         if (host->ops->unmap)
 775                 host->ops->unmap(host, virq);
 776         smp_mb();
 777
 778         /* Clear reverse map */
 779         hwirq = irq_map[virq].hwirq;
 780         switch(host->revmap_type) {
 781         case IRQ_HOST_MAP_LINEAR:
 782                 if (hwirq < host->revmap_data.linear.size)
 783                         host->revmap_data.linear.revmap[hwirq] = NO_IRQ;
 784                 break;
 785         case IRQ_HOST_MAP_TREE:
 786                 /* Check if radix tree allocated yet */
 787                 if (host->revmap_data.tree.gfp_mask == 0)
 788                         break;
 789                 irq_radix_wrlock(&flags);
 790                 radix_tree_delete(&host->revmap_data.tree, hwirq);
 791                 irq_radix_wrunlock(flags);
 792                 break;
 793         }
 794
 795         /* Destroy map */
 796         smp_mb();
 797         irq_map[virq].hwirq = host->inval_irq;
 798
 799         /* Set some flags */
 800         get_irq_desc(virq)->status |= IRQ_NOREQUEST;
 801
 802         /* Free it */
 803         irq_free_virt(virq, 1);
 804 }
 805 EXPORT_SYMBOL_GPL(irq_dispose_mapping);
 806
 807 unsigned int irq_find_mapping(struct irq_host *host,
 808                               irq_hw_number_t hwirq)
 809 {
 810         unsigned int i;
 811         unsigned int hint = hwirq % irq_virq_count;
 812
 813         /* Look for default host if nececssary */
 814         if (host == NULL)
 815                 host = irq_default_host;
 816         if (host == NULL)
 817                 return NO_IRQ;
 818
 819         /* legacy -> bail early */
 820         if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
 821                 return hwirq;
 822
 823         /* Slow path does a linear search of the map */
 824         if (hint < NUM_ISA_INTERRUPTS)
 825                 hint = NUM_ISA_INTERRUPTS;
 826         i = hint;
 827         do  {
 828                 if (irq_map[i].host == host &&
 829                     irq_map[i].hwirq == hwirq)
 830                         return i;
 831                 i++;
 832                 if (i >= irq_virq_count)
 833                         i = NUM_ISA_INTERRUPTS;
 834         } while(i != hint);
 835         return NO_IRQ;
 836 }
 837 EXPORT_SYMBOL_GPL(irq_find_mapping);
 838
 839
 840 unsigned int irq_radix_revmap(struct irq_host *host,
 841                               irq_hw_number_t hwirq)
 842 {
 843         struct radix_tree_root *tree;
 844         struct irq_map_entry *ptr;
 845         unsigned int virq;
 846         unsigned long flags;
 847
 848         WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);
 849
 850         /* Check if the radix tree exist yet. We test the value of
 851          * the gfp_mask for that. Sneaky but saves another int in the
 852          * structure. If not, we fallback to slow mode
 853          */
 854         tree = &host->revmap_data.tree;
 855         if (tree->gfp_mask == 0)
 856                 return irq_find_mapping(host, hwirq);
 857
 858         /* Now try to resolve */
 859         irq_radix_rdlock(&flags);
 860         ptr = radix_tree_lookup(tree, hwirq);
 861         irq_radix_rdunlock(flags);
 862
 863         /* Found it, return */
 864         if (ptr) {
 865                 virq = ptr - irq_map;
 866                 return virq;
 867         }
 868
 869         /* If not there, try to insert it */
 870         virq = irq_find_mapping(host, hwirq);
 871         if (virq != NO_IRQ) {
 872                 irq_radix_wrlock(&flags);
 873                 radix_tree_insert(tree, hwirq, &irq_map[virq]);
 874                 irq_radix_wrunlock(flags);
 875         }
 876         return virq;
 877 }
 878
 879 unsigned int irq_linear_revmap(struct irq_host *host,
 880                                irq_hw_number_t hwirq)
 881 {
 882         unsigned int *revmap;
 883
 884         WARN_ON(host->revmap_type != IRQ_HOST_MAP_LINEAR);
 885
 886         /* Check revmap bounds */
 887         if (unlikely(hwirq >= host->revmap_data.linear.size))
 888                 return irq_find_mapping(host, hwirq);
 889
 890         /* Check if revmap was allocated */
 891         revmap = host->revmap_data.linear.revmap;
 892         if (unlikely(revmap == NULL))
 893                 return irq_find_mapping(host, hwirq);
 894
 895         /* Fill up revmap with slow path if no mapping found */
 896         if (unlikely(revmap[hwirq] == NO_IRQ))
 897                 revmap[hwirq] = irq_find_mapping(host, hwirq);
 898
 899         return revmap[hwirq];
 900 }
 901
 902 unsigned int irq_alloc_virt(struct irq_host *host,
 903                             unsigned int count,
 904                             unsigned int hint)
 905 {
 906         unsigned long flags;
 907         unsigned int i, j, found = NO_IRQ;
 908
 909         if (count == 0 || count > (irq_virq_count - NUM_ISA_INTERRUPTS))
 910                 return NO_IRQ;
 911
 912         spin_lock_irqsave(&irq_big_lock, flags);
 913
 914         /* Use hint for 1 interrupt if any */
 915         if (count == 1 && hint >= NUM_ISA_INTERRUPTS &&
 916             hint < irq_virq_count && irq_map[hint].host == NULL) {
 917                 found = hint;
 918                 goto hint_found;
 919         }
 920
 921         /* Look for count consecutive numbers in the allocatable
 922          * (non-legacy) space
 923          */
 924         for (i = NUM_ISA_INTERRUPTS, j = 0; i < irq_virq_count; i++) {
 925                 if (irq_map[i].host != NULL)
 926                         j = 0;
 927                 else
 928                         j++;
 929
 930                 if (j == count) {
 931                         found = i - count + 1;
 932                         break;
 933                 }
 934         }
 935         if (found == NO_IRQ) {
 936                 spin_unlock_irqrestore(&irq_big_lock, flags);
 937                 return NO_IRQ;
 938         }
 939  hint_found:
 940         for (i = found; i < (found + count); i++) {
 941                 irq_map[i].hwirq = host->inval_irq;
 942                 smp_wmb();
 943                 irq_map[i].host = host;
 944         }
 945         spin_unlock_irqrestore(&irq_big_lock, flags);
 946         return found;
 947 }
 948
 949 void irq_free_virt(unsigned int virq, unsigned int count)
 950 {
 951         unsigned long flags;
 952         unsigned int i;
 953
 954         WARN_ON (virq < NUM_ISA_INTERRUPTS);
 955         WARN_ON (count == 0 || (virq + count) > irq_virq_count);
 956
 957         spin_lock_irqsave(&irq_big_lock, flags);
 958         for (i = virq; i < (virq + count); i++) {
 959                 struct irq_host *host;
 960
 961                 if (i < NUM_ISA_INTERRUPTS ||
 962                     (virq + count) > irq_virq_count)
 963                         continue;
 964
 965                 host = irq_map[i].host;
 966                 irq_map[i].hwirq = host->inval_irq;
 967                 smp_wmb();
 968                 irq_map[i].host = NULL;
 969         }
 970         spin_unlock_irqrestore(&irq_big_lock, flags);
 971 }
 972
 973 void irq_early_init(void)
 974 {
 975         unsigned int i;
 976
 977         for (i = 0; i < NR_IRQS; i++)
 978                 get_irq_desc(i)->status |= IRQ_NOREQUEST;
 979 }
 980
 981 /* We need to create the radix trees late */
 982 static int irq_late_init(void)
 983 {
 984         struct irq_host *h;
 985         unsigned long flags;
 986
 987         irq_radix_wrlock(&flags);
 988         list_for_each_entry(h, &irq_hosts, link) {
 989                 if (h->revmap_type == IRQ_HOST_MAP_TREE)
 990                         INIT_RADIX_TREE(&h->revmap_data.tree, GFP_ATOMIC);
 991         }
 992         irq_radix_wrunlock(flags);
 993
 994         return 0;
 995 }
 996 arch_initcall(irq_late_init);
 997
 998 #endif /* CONFIG_PPC_MERGE */
 999
1000 #ifdef CONFIG_PPC64
1001 static int __init setup_noirqdistrib(char *str)
1002 {
1003         distribute_irqs = 0;
1004         return 1;
1005 }
1006
1007 __setup("noirqdistrib", setup_noirqdistrib);
1008 #endif /* CONFIG_PPC64 */