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 #include <linux/of.h>
  57 #include <linux/of_irq.h>
  58
  59 #include <asm/uaccess.h>
  60 #include <asm/system.h>
  61 #include <asm/io.h>
  62 #include <asm/pgtable.h>
  63 #include <asm/irq.h>
  64 #include <asm/cache.h>
  65 #include <asm/prom.h>
  66 #include <asm/ptrace.h>
  67 #include <asm/machdep.h>
  68 #include <asm/udbg.h>
  69 #include <asm/dbell.h>
  70 #include <asm/smp.h>
  71
  72 #ifdef CONFIG_PPC64
  73 #include <asm/paca.h>
  74 #include <asm/firmware.h>
  75 #include <asm/lv1call.h>
  76 #endif
  77 #define CREATE_TRACE_POINTS
  78 #include <asm/trace.h>
  79
  80 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
  81 EXPORT_PER_CPU_SYMBOL(irq_stat);
  82
  83 int __irq_offset_value;
  84
  85 #ifdef CONFIG_PPC32
  86 EXPORT_SYMBOL(__irq_offset_value);
  87 atomic_t ppc_n_lost_interrupts;
  88
  89 #ifdef CONFIG_TAU_INT
  90 extern int tau_initialized;
  91 extern int tau_interrupts(int);
  92 #endif
  93 #endif /* CONFIG_PPC32 */
  94
  95 #ifdef CONFIG_PPC64
  96
  97 #ifndef CONFIG_SPARSE_IRQ
  98 EXPORT_SYMBOL(irq_desc);
  99 #endif
 100
 101 int distribute_irqs = 1;
 102
 103 static inline notrace unsigned long get_hard_enabled(void)
 104 {
 105         unsigned long enabled;
 106
 107         __asm__ __volatile__("lbz %0,%1(13)"
 108         : "=r" (enabled) : "i" (offsetof(struct paca_struct, hard_enabled)));
 109
 110         return enabled;
 111 }
 112
 113 static inline notrace void set_soft_enabled(unsigned long enable)
 114 {
 115         __asm__ __volatile__("stb %0,%1(13)"
 116         : : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
 117 }
 118
 119 notrace void arch_local_irq_restore(unsigned long en)
 120 {
 121         /*
 122          * get_paca()->soft_enabled = en;
 123          * Is it ever valid to use local_irq_restore(0) when soft_enabled is 1?
 124          * That was allowed before, and in such a case we do need to take care
 125          * that gcc will set soft_enabled directly via r13, not choose to use
 126          * an intermediate register, lest we're preempted to a different cpu.
 127          */
 128         set_soft_enabled(en);
 129         if (!en)
 130                 return;
 131
 132 #ifdef CONFIG_PPC_STD_MMU_64
 133         if (firmware_has_feature(FW_FEATURE_ISERIES)) {
 134                 /*
 135                  * Do we need to disable preemption here?  Not really: in the
 136                  * unlikely event that we're preempted to a different cpu in
 137                  * between getting r13, loading its lppaca_ptr, and loading
 138                  * its any_int, we might call iseries_handle_interrupts without
 139                  * an interrupt pending on the new cpu, but that's no disaster,
 140                  * is it?  And the business of preempting us off the old cpu
 141                  * would itself involve a local_irq_restore which handles the
 142                  * interrupt to that cpu.
 143                  *
 144                  * But use "local_paca->lppaca_ptr" instead of "get_lppaca()"
 145                  * to avoid any preemption checking added into get_paca().
 146                  */
 147                 if (local_paca->lppaca_ptr->int_dword.any_int)
 148                         iseries_handle_interrupts();
 149         }
 150 #endif /* CONFIG_PPC_STD_MMU_64 */
 151
 152         /*
 153          * if (get_paca()->hard_enabled) return;
 154          * But again we need to take care that gcc gets hard_enabled directly
 155          * via r13, not choose to use an intermediate register, lest we're
 156          * preempted to a different cpu in between the two instructions.
 157          */
 158         if (get_hard_enabled())
 159                 return;
 160
 161 #if defined(CONFIG_BOOKE) && defined(CONFIG_SMP)
 162         /* Check for pending doorbell interrupts and resend to ourself */
 163         doorbell_check_self();
 164 #endif
 165
 166         /*
 167          * Need to hard-enable interrupts here.  Since currently disabled,
 168          * no need to take further asm precautions against preemption; but
 169          * use local_paca instead of get_paca() to avoid preemption checking.
 170          */
 171         local_paca->hard_enabled = en;
 172
 173 #ifndef CONFIG_BOOKE
 174         /* On server, re-trigger the decrementer if it went negative since
 175          * some processors only trigger on edge transitions of the sign bit.
 176          *
 177          * BookE has a level sensitive decrementer (latches in TSR) so we
 178          * don't need that
 179          */
 180         if ((int)mfspr(SPRN_DEC) < 0)
 181                 mtspr(SPRN_DEC, 1);
 182 #endif /* CONFIG_BOOKE */
 183
 184         /*
 185          * Force the delivery of pending soft-disabled interrupts on PS3.
 186          * Any HV call will have this side effect.
 187          */
 188         if (firmware_has_feature(FW_FEATURE_PS3_LV1)) {
 189                 u64 tmp;
 190                 lv1_get_version_info(&tmp);
 191         }
 192
 193         __hard_irq_enable();
 194 }
 195 EXPORT_SYMBOL(arch_local_irq_restore);
 196 #endif /* CONFIG_PPC64 */
 197
 198 static int show_other_interrupts(struct seq_file *p, int prec)
 199 {
 200         int j;
 201
 202 #if defined(CONFIG_PPC32) && defined(CONFIG_TAU_INT)
 203         if (tau_initialized) {
 204                 seq_printf(p, "%*s: ", prec, "TAU");
 205                 for_each_online_cpu(j)
 206                         seq_printf(p, "%10u ", tau_interrupts(j));
 207                 seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
 208         }
 209 #endif /* CONFIG_PPC32 && CONFIG_TAU_INT */
 210
 211         seq_printf(p, "%*s: ", prec, "LOC");
 212         for_each_online_cpu(j)
 213                 seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs);
 214         seq_printf(p, "  Local timer interrupts\n");
 215
 216         seq_printf(p, "%*s: ", prec, "SPU");
 217         for_each_online_cpu(j)
 218                 seq_printf(p, "%10u ", per_cpu(irq_stat, j).spurious_irqs);
 219         seq_printf(p, "  Spurious interrupts\n");
 220
 221         seq_printf(p, "%*s: ", prec, "CNT");
 222         for_each_online_cpu(j)
 223                 seq_printf(p, "%10u ", per_cpu(irq_stat, j).pmu_irqs);
 224         seq_printf(p, "  Performance monitoring interrupts\n");
 225
 226         seq_printf(p, "%*s: ", prec, "MCE");
 227         for_each_online_cpu(j)
 228                 seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions);
 229         seq_printf(p, "  Machine check exceptions\n");
 230
 231         return 0;
 232 }
 233
 234 int show_interrupts(struct seq_file *p, void *v)
 235 {
 236         unsigned long flags, any_count = 0;
 237         int i = *(loff_t *) v, j, prec;
 238         struct irqaction *action;
 239         struct irq_desc *desc;
 240
 241         if (i > nr_irqs)
 242                 return 0;
 243
 244         for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
 245                 j *= 10;
 246
 247         if (i == nr_irqs)
 248                 return show_other_interrupts(p, prec);
 249
 250         /* print header */
 251         if (i == 0) {
 252                 seq_printf(p, "%*s", prec + 8, "");
 253                 for_each_online_cpu(j)
 254                         seq_printf(p, "CPU%-8d", j);
 255                 seq_putc(p, '\n');
 256         }
 257
 258         desc = irq_to_desc(i);
 259         if (!desc)
 260                 return 0;
 261
 262         raw_spin_lock_irqsave(&desc->lock, flags);
 263         for_each_online_cpu(j)
 264                 any_count |= kstat_irqs_cpu(i, j);
 265         action = desc->action;
 266         if (!action && !any_count)
 267                 goto out;
 268
 269         seq_printf(p, "%*d: ", prec, i);
 270         for_each_online_cpu(j)
 271                 seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
 272
 273         if (desc->chip)
 274                 seq_printf(p, "  %-16s", desc->chip->name);
 275         else
 276                 seq_printf(p, "  %-16s", "None");
 277         seq_printf(p, " %-8s", (desc->status & IRQ_LEVEL) ? "Level" : "Edge");
 278
 279         if (action) {
 280                 seq_printf(p, "     %s", action->name);
 281                 while ((action = action->next) != NULL)
 282                         seq_printf(p, ", %s", action->name);
 283         }
 284
 285         seq_putc(p, '\n');
 286 out:
 287         raw_spin_unlock_irqrestore(&desc->lock, flags);
 288         return 0;
 289 }
 290
 291 /*
 292  * /proc/stat helpers
 293  */
 294 u64 arch_irq_stat_cpu(unsigned int cpu)
 295 {
 296         u64 sum = per_cpu(irq_stat, cpu).timer_irqs;
 297
 298         sum += per_cpu(irq_stat, cpu).pmu_irqs;
 299         sum += per_cpu(irq_stat, cpu).mce_exceptions;
 300         sum += per_cpu(irq_stat, cpu).spurious_irqs;
 301
 302         return sum;
 303 }
 304
 305 #ifdef CONFIG_HOTPLUG_CPU
 306 void fixup_irqs(const struct cpumask *map)
 307 {
 308         struct irq_desc *desc;
 309         unsigned int irq;
 310         static int warned;
 311         cpumask_var_t mask;
 312
 313         alloc_cpumask_var(&mask, GFP_KERNEL);
 314
 315         for_each_irq(irq) {
 316                 desc = irq_to_desc(irq);
 317                 if (!desc)
 318                         continue;
 319
 320                 if (desc->status & IRQ_PER_CPU)
 321                         continue;
 322
 323                 cpumask_and(mask, desc->affinity, map);
 324                 if (cpumask_any(mask) >= nr_cpu_ids) {
 325                         printk("Breaking affinity for irq %i\n", irq);
 326                         cpumask_copy(mask, map);
 327                 }
 328                 if (desc->chip->set_affinity)
 329                         desc->chip->set_affinity(irq, mask);
 330                 else if (desc->action && !(warned++))
 331                         printk("Cannot set affinity for irq %i\n", irq);
 332         }
 333
 334         free_cpumask_var(mask);
 335
 336         local_irq_enable();
 337         mdelay(1);
 338         local_irq_disable();
 339 }
 340 #endif
 341
 342 static inline void handle_one_irq(unsigned int irq)
 343 {
 344         struct thread_info *curtp, *irqtp;
 345         unsigned long saved_sp_limit;
 346         struct irq_desc *desc;
 347
 348         /* Switch to the irq stack to handle this */
 349         curtp = current_thread_info();
 350         irqtp = hardirq_ctx[smp_processor_id()];
 351
 352         if (curtp == irqtp) {
 353                 /* We're already on the irq stack, just handle it */
 354                 generic_handle_irq(irq);
 355                 return;
 356         }
 357
 358         desc = irq_to_desc(irq);
 359         saved_sp_limit = current->thread.ksp_limit;
 360
 361         irqtp->task = curtp->task;
 362         irqtp->flags = 0;
 363
 364         /* Copy the softirq bits in preempt_count so that the
 365          * softirq checks work in the hardirq context. */
 366         irqtp->preempt_count = (irqtp->preempt_count & ~SOFTIRQ_MASK) |
 367                                (curtp->preempt_count & SOFTIRQ_MASK);
 368
 369         current->thread.ksp_limit = (unsigned long)irqtp +
 370                 _ALIGN_UP(sizeof(struct thread_info), 16);
 371
 372         call_handle_irq(irq, desc, irqtp, desc->handle_irq);
 373         current->thread.ksp_limit = saved_sp_limit;
 374         irqtp->task = NULL;
 375
 376         /* Set any flag that may have been set on the
 377          * alternate stack
 378          */
 379         if (irqtp->flags)
 380                 set_bits(irqtp->flags, &curtp->flags);
 381 }
 382
 383 static inline void check_stack_overflow(void)
 384 {
 385 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 386         long sp;
 387
 388         sp = __get_SP() & (THREAD_SIZE-1);
 389
 390         /* check for stack overflow: is there less than 2KB free? */
 391         if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
 392                 printk("do_IRQ: stack overflow: %ld\n",
 393                         sp - sizeof(struct thread_info));
 394                 dump_stack();
 395         }
 396 #endif
 397 }
 398
 399 void do_IRQ(struct pt_regs *regs)
 400 {
 401         struct pt_regs *old_regs = set_irq_regs(regs);
 402         unsigned int irq;
 403
 404         trace_irq_entry(regs);
 405
 406         irq_enter();
 407
 408         check_stack_overflow();
 409
 410         irq = ppc_md.get_irq();
 411
 412         if (irq != NO_IRQ && irq != NO_IRQ_IGNORE)
 413                 handle_one_irq(irq);
 414         else if (irq != NO_IRQ_IGNORE)
 415                 __get_cpu_var(irq_stat).spurious_irqs++;
 416
 417         irq_exit();
 418         set_irq_regs(old_regs);
 419
 420 #ifdef CONFIG_PPC_ISERIES
 421         if (firmware_has_feature(FW_FEATURE_ISERIES) &&
 422                         get_lppaca()->int_dword.fields.decr_int) {
 423                 get_lppaca()->int_dword.fields.decr_int = 0;
 424                 /* Signal a fake decrementer interrupt */
 425                 timer_interrupt(regs);
 426         }
 427 #endif
 428
 429         trace_irq_exit(regs);
 430 }
 431
 432 void __init init_IRQ(void)
 433 {
 434         if (ppc_md.init_IRQ)
 435                 ppc_md.init_IRQ();
 436
 437         exc_lvl_ctx_init();
 438
 439         irq_ctx_init();
 440 }
 441
 442 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
 443 struct thread_info   *critirq_ctx[NR_CPUS] __read_mostly;
 444 struct thread_info    *dbgirq_ctx[NR_CPUS] __read_mostly;
 445 struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;
 446
 447 void exc_lvl_ctx_init(void)
 448 {
 449         struct thread_info *tp;
 450         int i, hw_cpu;
 451
 452         for_each_possible_cpu(i) {
 453                 hw_cpu = get_hard_smp_processor_id(i);
 454                 memset((void *)critirq_ctx[hw_cpu], 0, THREAD_SIZE);
 455                 tp = critirq_ctx[hw_cpu];
 456                 tp->cpu = i;
 457                 tp->preempt_count = 0;
 458
 459 #ifdef CONFIG_BOOKE
 460                 memset((void *)dbgirq_ctx[hw_cpu], 0, THREAD_SIZE);
 461                 tp = dbgirq_ctx[hw_cpu];
 462                 tp->cpu = i;
 463                 tp->preempt_count = 0;
 464
 465                 memset((void *)mcheckirq_ctx[hw_cpu], 0, THREAD_SIZE);
 466                 tp = mcheckirq_ctx[hw_cpu];
 467                 tp->cpu = i;
 468                 tp->preempt_count = HARDIRQ_OFFSET;
 469 #endif
 470         }
 471 }
 472 #endif
 473
 474 struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;
 475 struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly;
 476
 477 void irq_ctx_init(void)
 478 {
 479         struct thread_info *tp;
 480         int i;
 481
 482         for_each_possible_cpu(i) {
 483                 memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
 484                 tp = softirq_ctx[i];
 485                 tp->cpu = i;
 486                 tp->preempt_count = 0;
 487
 488                 memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
 489                 tp = hardirq_ctx[i];
 490                 tp->cpu = i;
 491                 tp->preempt_count = HARDIRQ_OFFSET;
 492         }
 493 }
 494
 495 static inline void do_softirq_onstack(void)
 496 {
 497         struct thread_info *curtp, *irqtp;
 498         unsigned long saved_sp_limit = current->thread.ksp_limit;
 499
 500         curtp = current_thread_info();
 501         irqtp = softirq_ctx[smp_processor_id()];
 502         irqtp->task = curtp->task;
 503         current->thread.ksp_limit = (unsigned long)irqtp +
 504                                     _ALIGN_UP(sizeof(struct thread_info), 16);
 505         call_do_softirq(irqtp);
 506         current->thread.ksp_limit = saved_sp_limit;
 507         irqtp->task = NULL;
 508 }
 509
 510 void do_softirq(void)
 511 {
 512         unsigned long flags;
 513
 514         if (in_interrupt())
 515                 return;
 516
 517         local_irq_save(flags);
 518
 519         if (local_softirq_pending())
 520                 do_softirq_onstack();
 521
 522         local_irq_restore(flags);
 523 }
 524
 525
 526 /*
 527  * IRQ controller and virtual interrupts
 528  */
 529
 530 static LIST_HEAD(irq_hosts);
 531 static DEFINE_RAW_SPINLOCK(irq_big_lock);
 532 static unsigned int revmap_trees_allocated;
 533 static DEFINE_MUTEX(revmap_trees_mutex);
 534 struct irq_map_entry irq_map[NR_IRQS];
 535 static unsigned int irq_virq_count = NR_IRQS;
 536 static struct irq_host *irq_default_host;
 537
 538 irq_hw_number_t virq_to_hw(unsigned int virq)
 539 {
 540         return irq_map[virq].hwirq;
 541 }
 542 EXPORT_SYMBOL_GPL(virq_to_hw);
 543
 544 static int default_irq_host_match(struct irq_host *h, struct device_node *np)
 545 {
 546         return h->of_node != NULL && h->of_node == np;
 547 }
 548
 549 struct irq_host *irq_alloc_host(struct device_node *of_node,
 550                                 unsigned int revmap_type,
 551                                 unsigned int revmap_arg,
 552                                 struct irq_host_ops *ops,
 553                                 irq_hw_number_t inval_irq)
 554 {
 555         struct irq_host *host;
 556         unsigned int size = sizeof(struct irq_host);
 557         unsigned int i;
 558         unsigned int *rmap;
 559         unsigned long flags;
 560
 561         /* Allocate structure and revmap table if using linear mapping */
 562         if (revmap_type == IRQ_HOST_MAP_LINEAR)
 563                 size += revmap_arg * sizeof(unsigned int);
 564         host = zalloc_maybe_bootmem(size, GFP_KERNEL);
 565         if (host == NULL)
 566                 return NULL;
 567
 568         /* Fill structure */
 569         host->revmap_type = revmap_type;
 570         host->inval_irq = inval_irq;
 571         host->ops = ops;
 572         host->of_node = of_node_get(of_node);
 573
 574         if (host->ops->match == NULL)
 575                 host->ops->match = default_irq_host_match;
 576
 577         raw_spin_lock_irqsave(&irq_big_lock, flags);
 578
 579         /* If it's a legacy controller, check for duplicates and
 580          * mark it as allocated (we use irq 0 host pointer for that
 581          */
 582         if (revmap_type == IRQ_HOST_MAP_LEGACY) {
 583                 if (irq_map[0].host != NULL) {
 584                         raw_spin_unlock_irqrestore(&irq_big_lock, flags);
 585                         /* If we are early boot, we can't free the structure,
 586                          * too bad...
 587                          * this will be fixed once slab is made available early
 588                          * instead of the current cruft
 589                          */
 590                         if (mem_init_done) {
 591                                 of_node_put(host->of_node);
 592                                 kfree(host);
 593                         }
 594                         return NULL;
 595                 }
 596                 irq_map[0].host = host;
 597         }
 598
 599         list_add(&host->link, &irq_hosts);
 600         raw_spin_unlock_irqrestore(&irq_big_lock, flags);
 601
 602         /* Additional setups per revmap type */
 603         switch(revmap_type) {
 604         case IRQ_HOST_MAP_LEGACY:
 605                 /* 0 is always the invalid number for legacy */
 606                 host->inval_irq = 0;
 607                 /* setup us as the host for all legacy interrupts */
 608                 for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
 609                         irq_map[i].hwirq = i;
 610                         smp_wmb();
 611                         irq_map[i].host = host;
 612                         smp_wmb();
 613
 614                         /* Clear norequest flags */
 615                         irq_to_desc(i)->status &= ~IRQ_NOREQUEST;
 616
 617                         /* Legacy flags are left to default at this point,
 618                          * one can then use irq_create_mapping() to
 619                          * explicitly change them
 620                          */
 621                         ops->map(host, i, i);
 622                 }
 623                 break;
 624         case IRQ_HOST_MAP_LINEAR:
 625                 rmap = (unsigned int *)(host + 1);
 626                 for (i = 0; i < revmap_arg; i++)
 627                         rmap[i] = NO_IRQ;
 628                 host->revmap_data.linear.size = revmap_arg;
 629                 smp_wmb();
 630                 host->revmap_data.linear.revmap = rmap;
 631                 break;
 632         default:
 633                 break;
 634         }
 635
 636         pr_debug("irq: Allocated host of type %d @0x%p\n", revmap_type, host);
 637
 638         return host;
 639 }
 640
 641 struct irq_host *irq_find_host(struct device_node *node)
 642 {
 643         struct irq_host *h, *found = NULL;
 644         unsigned long flags;
 645
 646         /* We might want to match the legacy controller last since
 647          * it might potentially be set to match all interrupts in
 648          * the absence of a device node. This isn't a problem so far
 649          * yet though...
 650          */
 651         raw_spin_lock_irqsave(&irq_big_lock, flags);
 652         list_for_each_entry(h, &irq_hosts, link)
 653                 if (h->ops->match(h, node)) {
 654                         found = h;
 655                         break;
 656                 }
 657         raw_spin_unlock_irqrestore(&irq_big_lock, flags);
 658         return found;
 659 }
 660 EXPORT_SYMBOL_GPL(irq_find_host);
 661
 662 void irq_set_default_host(struct irq_host *host)
 663 {
 664         pr_debug("irq: Default host set to @0x%p\n", host);
 665
 666         irq_default_host = host;
 667 }
 668
 669 void irq_set_virq_count(unsigned int count)
 670 {
 671         pr_debug("irq: Trying to set virq count to %d\n", count);
 672
 673         BUG_ON(count < NUM_ISA_INTERRUPTS);
 674         if (count < NR_IRQS)
 675                 irq_virq_count = count;
 676 }
 677
 678 static int irq_setup_virq(struct irq_host *host, unsigned int virq,
 679                             irq_hw_number_t hwirq)
 680 {
 681         struct irq_desc *desc;
 682
 683         desc = irq_to_desc_alloc_node(virq, 0);
 684         if (!desc) {
 685                 pr_debug("irq: -> allocating desc failed\n");
 686                 goto error;
 687         }
 688
 689         /* Clear IRQ_NOREQUEST flag */
 690         desc->status &= ~IRQ_NOREQUEST;
 691
 692         /* map it */
 693         smp_wmb();
 694         irq_map[virq].hwirq = hwirq;
 695         smp_mb();
 696
 697         if (host->ops->map(host, virq, hwirq)) {
 698                 pr_debug("irq: -> mapping failed, freeing\n");
 699                 goto error;
 700         }
 701
 702         return 0;
 703
 704 error:
 705         irq_free_virt(virq, 1);
 706         return -1;
 707 }
 708
 709 unsigned int irq_create_direct_mapping(struct irq_host *host)
 710 {
 711         unsigned int virq;
 712
 713         if (host == NULL)
 714                 host = irq_default_host;
 715
 716         BUG_ON(host == NULL);
 717         WARN_ON(host->revmap_type != IRQ_HOST_MAP_NOMAP);
 718
 719         virq = irq_alloc_virt(host, 1, 0);
 720         if (virq == NO_IRQ) {
 721                 pr_debug("irq: create_direct virq allocation failed\n");
 722                 return NO_IRQ;
 723         }
 724
 725         pr_debug("irq: create_direct obtained virq %d\n", virq);
 726
 727         if (irq_setup_virq(host, virq, virq))
 728                 return NO_IRQ;
 729
 730         return virq;
 731 }
 732
 733 unsigned int irq_create_mapping(struct irq_host *host,
 734                                 irq_hw_number_t hwirq)
 735 {
 736         unsigned int virq, hint;
 737
 738         pr_debug("irq: irq_create_mapping(0x%p, 0x%lx)\n", host, hwirq);
 739
 740         /* Look for default host if nececssary */
 741         if (host == NULL)
 742                 host = irq_default_host;
 743         if (host == NULL) {
 744                 printk(KERN_WARNING "irq_create_mapping called for"
 745                        " NULL host, hwirq=%lx\n", hwirq);
 746                 WARN_ON(1);
 747                 return NO_IRQ;
 748         }
 749         pr_debug("irq: -> using host @%p\n", host);
 750
 751         /* Check if mapping already exist, if it does, call
 752          * host->ops->map() to update the flags
 753          */
 754         virq = irq_find_mapping(host, hwirq);
 755         if (virq != NO_IRQ) {
 756                 if (host->ops->remap)
 757                         host->ops->remap(host, virq, hwirq);
 758                 pr_debug("irq: -> existing mapping on virq %d\n", virq);
 759                 return virq;
 760         }
 761
 762         /* Get a virtual interrupt number */
 763         if (host->revmap_type == IRQ_HOST_MAP_LEGACY) {
 764                 /* Handle legacy */
 765                 virq = (unsigned int)hwirq;
 766                 if (virq == 0 || virq >= NUM_ISA_INTERRUPTS)
 767                         return NO_IRQ;
 768                 return virq;
 769         } else {
 770                 /* Allocate a virtual interrupt number */
 771                 hint = hwirq % irq_virq_count;
 772                 virq = irq_alloc_virt(host, 1, hint);
 773                 if (virq == NO_IRQ) {
 774                         pr_debug("irq: -> virq allocation failed\n");
 775                         return NO_IRQ;
 776                 }
 777         }
 778
 779         if (irq_setup_virq(host, virq, hwirq))
 780                 return NO_IRQ;
 781
 782         printk(KERN_DEBUG "irq: irq %lu on host %s mapped to virtual irq %u\n",
 783                 hwirq, host->of_node ? host->of_node->full_name : "null", virq);
 784
 785         return virq;
 786 }
 787 EXPORT_SYMBOL_GPL(irq_create_mapping);
 788
 789 unsigned int irq_create_of_mapping(struct device_node *controller,
 790                                    const u32 *intspec, unsigned int intsize)
 791 {
 792         struct irq_host *host;
 793         irq_hw_number_t hwirq;
 794         unsigned int type = IRQ_TYPE_NONE;
 795         unsigned int virq;
 796
 797         if (controller == NULL)
 798                 host = irq_default_host;
 799         else
 800                 host = irq_find_host(controller);
 801         if (host == NULL) {
 802                 printk(KERN_WARNING "irq: no irq host found for %s !\n",
 803                        controller->full_name);
 804                 return NO_IRQ;
 805         }
 806
 807         /* If host has no translation, then we assume interrupt line */
 808         if (host->ops->xlate == NULL)
 809                 hwirq = intspec[0];
 810         else {
 811                 if (host->ops->xlate(host, controller, intspec, intsize,
 812                                      &hwirq, &type))
 813                         return NO_IRQ;
 814         }
 815
 816         /* Create mapping */
 817         virq = irq_create_mapping(host, hwirq);
 818         if (virq == NO_IRQ)
 819                 return virq;
 820
 821         /* Set type if specified and different than the current one */
 822         if (type != IRQ_TYPE_NONE &&
 823             type != (irq_to_desc(virq)->status & IRQF_TRIGGER_MASK))
 824                 set_irq_type(virq, type);
 825         return virq;
 826 }
 827 EXPORT_SYMBOL_GPL(irq_create_of_mapping);
 828
 829 void irq_dispose_mapping(unsigned int virq)
 830 {
 831         struct irq_host *host;
 832         irq_hw_number_t hwirq;
 833
 834         if (virq == NO_IRQ)
 835                 return;
 836
 837         host = irq_map[virq].host;
 838         WARN_ON (host == NULL);
 839         if (host == NULL)
 840                 return;
 841
 842         /* Never unmap legacy interrupts */
 843         if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
 844                 return;
 845
 846         /* remove chip and handler */
 847         set_irq_chip_and_handler(virq, NULL, NULL);
 848
 849         /* Make sure it's completed */
 850         synchronize_irq(virq);
 851
 852         /* Tell the PIC about it */
 853         if (host->ops->unmap)
 854                 host->ops->unmap(host, virq);
 855         smp_mb();
 856
 857         /* Clear reverse map */
 858         hwirq = irq_map[virq].hwirq;
 859         switch(host->revmap_type) {
 860         case IRQ_HOST_MAP_LINEAR:
 861                 if (hwirq < host->revmap_data.linear.size)
 862                         host->revmap_data.linear.revmap[hwirq] = NO_IRQ;
 863                 break;
 864         case IRQ_HOST_MAP_TREE:
 865                 /*
 866                  * Check if radix tree allocated yet, if not then nothing to
 867                  * remove.
 868                  */
 869                 smp_rmb();
 870                 if (revmap_trees_allocated < 1)
 871                         break;
 872                 mutex_lock(&revmap_trees_mutex);
 873                 radix_tree_delete(&host->revmap_data.tree, hwirq);
 874                 mutex_unlock(&revmap_trees_mutex);
 875                 break;
 876         }
 877
 878         /* Destroy map */
 879         smp_mb();
 880         irq_map[virq].hwirq = host->inval_irq;
 881
 882         /* Set some flags */
 883         irq_to_desc(virq)->status |= IRQ_NOREQUEST;
 884
 885         /* Free it */
 886         irq_free_virt(virq, 1);
 887 }
 888 EXPORT_SYMBOL_GPL(irq_dispose_mapping);
 889
 890 unsigned int irq_find_mapping(struct irq_host *host,
 891                               irq_hw_number_t hwirq)
 892 {
 893         unsigned int i;
 894         unsigned int hint = hwirq % irq_virq_count;
 895
 896         /* Look for default host if nececssary */
 897         if (host == NULL)
 898                 host = irq_default_host;
 899         if (host == NULL)
 900                 return NO_IRQ;
 901
 902         /* legacy -> bail early */
 903         if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
 904                 return hwirq;
 905
 906         /* Slow path does a linear search of the map */
 907         if (hint < NUM_ISA_INTERRUPTS)
 908                 hint = NUM_ISA_INTERRUPTS;
 909         i = hint;
 910         do  {
 911                 if (irq_map[i].host == host &&
 912                     irq_map[i].hwirq == hwirq)
 913                         return i;
 914                 i++;
 915                 if (i >= irq_virq_count)
 916                         i = NUM_ISA_INTERRUPTS;
 917         } while(i != hint);
 918         return NO_IRQ;
 919 }
 920 EXPORT_SYMBOL_GPL(irq_find_mapping);
 921
 922
 923 unsigned int irq_radix_revmap_lookup(struct irq_host *host,
 924                                      irq_hw_number_t hwirq)
 925 {
 926         struct irq_map_entry *ptr;
 927         unsigned int virq;
 928
 929         WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);
 930
 931         /*
 932          * Check if the radix tree exists and has bee initialized.
 933          * If not, we fallback to slow mode
 934          */
 935         if (revmap_trees_allocated < 2)
 936                 return irq_find_mapping(host, hwirq);
 937
 938         /* Now try to resolve */
 939         /*
 940          * No rcu_read_lock(ing) needed, the ptr returned can't go under us
 941          * as it's referencing an entry in the static irq_map table.
 942          */
 943         ptr = radix_tree_lookup(&host->revmap_data.tree, hwirq);
 944
 945         /*
 946          * If found in radix tree, then fine.
 947          * Else fallback to linear lookup - this should not happen in practice
 948          * as it means that we failed to insert the node in the radix tree.
 949          */
 950         if (ptr)
 951                 virq = ptr - irq_map;
 952         else
 953                 virq = irq_find_mapping(host, hwirq);
 954
 955         return virq;
 956 }
 957
 958 void irq_radix_revmap_insert(struct irq_host *host, unsigned int virq,
 959                              irq_hw_number_t hwirq)
 960 {
 961
 962         WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);
 963
 964         /*
 965          * Check if the radix tree exists yet.
 966          * If not, then the irq will be inserted into the tree when it gets
 967          * initialized.
 968          */
 969         smp_rmb();
 970         if (revmap_trees_allocated < 1)
 971                 return;
 972
 973         if (virq != NO_IRQ) {
 974                 mutex_lock(&revmap_trees_mutex);
 975                 radix_tree_insert(&host->revmap_data.tree, hwirq,
 976                                   &irq_map[virq]);
 977                 mutex_unlock(&revmap_trees_mutex);
 978         }
 979 }
 980
 981 unsigned int irq_linear_revmap(struct irq_host *host,
 982                                irq_hw_number_t hwirq)
 983 {
 984         unsigned int *revmap;
 985
 986         WARN_ON(host->revmap_type != IRQ_HOST_MAP_LINEAR);
 987
 988         /* Check revmap bounds */
 989         if (unlikely(hwirq >= host->revmap_data.linear.size))
 990                 return irq_find_mapping(host, hwirq);
 991
 992         /* Check if revmap was allocated */
 993         revmap = host->revmap_data.linear.revmap;
 994         if (unlikely(revmap == NULL))
 995                 return irq_find_mapping(host, hwirq);
 996
 997         /* Fill up revmap with slow path if no mapping found */
 998         if (unlikely(revmap[hwirq] == NO_IRQ))
 999                 revmap[hwirq] = irq_find_mapping(host, hwirq);
1000
1001         return revmap[hwirq];
1002 }
1003
1004 unsigned int irq_alloc_virt(struct irq_host *host,
1005                             unsigned int count,
1006                             unsigned int hint)
1007 {
1008         unsigned long flags;
1009         unsigned int i, j, found = NO_IRQ;
1010
1011         if (count == 0 || count > (irq_virq_count - NUM_ISA_INTERRUPTS))
1012                 return NO_IRQ;
1013
1014         raw_spin_lock_irqsave(&irq_big_lock, flags);
1015
1016         /* Use hint for 1 interrupt if any */
1017         if (count == 1 && hint >= NUM_ISA_INTERRUPTS &&
1018             hint < irq_virq_count && irq_map[hint].host == NULL) {
1019                 found = hint;
1020                 goto hint_found;
1021         }
1022
1023         /* Look for count consecutive numbers in the allocatable
1024          * (non-legacy) space
1025          */
1026         for (i = NUM_ISA_INTERRUPTS, j = 0; i < irq_virq_count; i++) {
1027                 if (irq_map[i].host != NULL)
1028                         j = 0;
1029                 else
1030                         j++;
1031
1032                 if (j == count) {
1033                         found = i - count + 1;
1034                         break;
1035                 }
1036         }
1037         if (found == NO_IRQ) {
1038                 raw_spin_unlock_irqrestore(&irq_big_lock, flags);
1039                 return NO_IRQ;
1040         }
1041  hint_found:
1042         for (i = found; i < (found + count); i++) {
1043                 irq_map[i].hwirq = host->inval_irq;
1044                 smp_wmb();
1045                 irq_map[i].host = host;
1046         }
1047         raw_spin_unlock_irqrestore(&irq_big_lock, flags);
1048         return found;
1049 }
1050
1051 void irq_free_virt(unsigned int virq, unsigned int count)
1052 {
1053         unsigned long flags;
1054         unsigned int i;
1055
1056         WARN_ON (virq < NUM_ISA_INTERRUPTS);
1057         WARN_ON (count == 0 || (virq + count) > irq_virq_count);
1058
1059         raw_spin_lock_irqsave(&irq_big_lock, flags);
1060         for (i = virq; i < (virq + count); i++) {
1061                 struct irq_host *host;
1062
1063                 if (i < NUM_ISA_INTERRUPTS ||
1064                     (virq + count) > irq_virq_count)
1065                         continue;
1066
1067                 host = irq_map[i].host;
1068                 irq_map[i].hwirq = host->inval_irq;
1069                 smp_wmb();
1070                 irq_map[i].host = NULL;
1071         }
1072         raw_spin_unlock_irqrestore(&irq_big_lock, flags);
1073 }
1074
1075 int arch_early_irq_init(void)
1076 {
1077         struct irq_desc *desc;
1078         int i;
1079
1080         for (i = 0; i < NR_IRQS; i++) {
1081                 desc = irq_to_desc(i);
1082                 if (desc)
1083                         desc->status |= IRQ_NOREQUEST;
1084         }
1085
1086         return 0;
1087 }
1088
1089 int arch_init_chip_data(struct irq_desc *desc, int node)
1090 {
1091         desc->status |= IRQ_NOREQUEST;
1092         return 0;
1093 }
1094
1095 /* We need to create the radix trees late */
1096 static int irq_late_init(void)
1097 {
1098         struct irq_host *h;
1099         unsigned int i;
1100
1101         /*
1102          * No mutual exclusion with respect to accessors of the tree is needed
1103          * here as the synchronization is done via the state variable
1104          * revmap_trees_allocated.
1105          */
1106         list_for_each_entry(h, &irq_hosts, link) {
1107                 if (h->revmap_type == IRQ_HOST_MAP_TREE)
1108                         INIT_RADIX_TREE(&h->revmap_data.tree, GFP_KERNEL);
1109         }
1110
1111         /*
1112          * Make sure the radix trees inits are visible before setting
1113          * the flag
1114          */
1115         smp_wmb();
1116         revmap_trees_allocated = 1;
1117
1118         /*
1119          * Insert the reverse mapping for those interrupts already present
1120          * in irq_map[].
1121          */
1122         mutex_lock(&revmap_trees_mutex);
1123         for (i = 0; i < irq_virq_count; i++) {
1124                 if (irq_map[i].host &&
1125                     (irq_map[i].host->revmap_type == IRQ_HOST_MAP_TREE))
1126                         radix_tree_insert(&irq_map[i].host->revmap_data.tree,
1127                                           irq_map[i].hwirq, &irq_map[i]);
1128         }
1129         mutex_unlock(&revmap_trees_mutex);
1130
1131         /*
1132          * Make sure the radix trees insertions are visible before setting
1133          * the flag
1134          */
1135         smp_wmb();
1136         revmap_trees_allocated = 2;
1137
1138         return 0;
1139 }
1140 arch_initcall(irq_late_init);
1141
1142 #ifdef CONFIG_VIRQ_DEBUG
1143 static int virq_debug_show(struct seq_file *m, void *private)
1144 {
1145         unsigned long flags;
1146         struct irq_desc *desc;
1147         const char *p;
1148         static const char none[] = "none";
1149         int i;
1150
1151         seq_printf(m, "%-5s  %-7s  %-15s  %s\n", "virq", "hwirq",
1152                       "chip name", "host name");
1153
1154         for (i = 1; i < nr_irqs; i++) {
1155                 desc = irq_to_desc(i);
1156                 if (!desc)
1157                         continue;
1158
1159                 raw_spin_lock_irqsave(&desc->lock, flags);
1160
1161                 if (desc->action && desc->action->handler) {
1162                         seq_printf(m, "%5d  ", i);
1163                         seq_printf(m, "0x%05lx  ", virq_to_hw(i));
1164
1165                         if (desc->chip && desc->chip->name)
1166                                 p = desc->chip->name;
1167                         else
1168                                 p = none;
1169                         seq_printf(m, "%-15s  ", p);
1170
1171                         if (irq_map[i].host && irq_map[i].host->of_node)
1172                                 p = irq_map[i].host->of_node->full_name;
1173                         else
1174                                 p = none;
1175                         seq_printf(m, "%s\n", p);
1176                 }
1177
1178                 raw_spin_unlock_irqrestore(&desc->lock, flags);
1179         }
1180
1181         return 0;
1182 }
1183
1184 static int virq_debug_open(struct inode *inode, struct file *file)
1185 {
1186         return single_open(file, virq_debug_show, inode->i_private);
1187 }
1188
1189 static const struct file_operations virq_debug_fops = {
1190         .open = virq_debug_open,
1191         .read = seq_read,
1192         .llseek = seq_lseek,
1193         .release = single_release,
1194 };
1195
1196 static int __init irq_debugfs_init(void)
1197 {
1198         if (debugfs_create_file("virq_mapping", S_IRUGO, powerpc_debugfs_root,
1199                                  NULL, &virq_debug_fops) == NULL)
1200                 return -ENOMEM;
1201
1202         return 0;
1203 }
1204 __initcall(irq_debugfs_init);
1205 #endif /* CONFIG_VIRQ_DEBUG */
1206
1207 #ifdef CONFIG_PPC64
1208 static int __init setup_noirqdistrib(char *str)
1209 {
1210         distribute_irqs = 0;
1211         return 1;
1212 }
1213
1214 __setup("noirqdistrib", setup_noirqdistrib);
1215 #endif /* CONFIG_PPC64 */