kernel/irq/irqdesc.c

   1 /*
   2  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   3  * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
   4  *
   5  * This file contains the interrupt descriptor management code
   6  *
   7  * Detailed information is available in Documentation/DocBook/genericirq
   8  *
   9  */
  10 #include <linux/irq.h>
  11 #include <linux/slab.h>
  12 #include <linux/export.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/kernel_stat.h>
  15 #include <linux/radix-tree.h>
  16 #include <linux/bitmap.h>
  17 #include <linux/irqdomain.h>
  18
  19 #include "internals.h"
  20
  21 /*
  22  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  23  */
  24 static struct lock_class_key irq_desc_lock_class;
  25
  26 #if defined(CONFIG_SMP)
  27 static void __init init_irq_default_affinity(void)
  28 {
  29         alloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
  30         cpumask_setall(irq_default_affinity);
  31 }
  32 #else
  33 static void __init init_irq_default_affinity(void)
  34 {
  35 }
  36 #endif
  37
  38 #ifdef CONFIG_SMP
  39 static int alloc_masks(struct irq_desc *desc, gfp_t gfp, int node)
  40 {
  41         if (!zalloc_cpumask_var_node(&desc->irq_data.affinity, gfp, node))
  42                 return -ENOMEM;
  43
  44 #ifdef CONFIG_GENERIC_PENDING_IRQ
  45         if (!zalloc_cpumask_var_node(&desc->pending_mask, gfp, node)) {
  46                 free_cpumask_var(desc->irq_data.affinity);
  47                 return -ENOMEM;
  48         }
  49 #endif
  50         return 0;
  51 }
  52
  53 static void desc_smp_init(struct irq_desc *desc, int node)
  54 {
  55         desc->irq_data.node = node;
  56         cpumask_copy(desc->irq_data.affinity, irq_default_affinity);
  57 #ifdef CONFIG_GENERIC_PENDING_IRQ
  58         cpumask_clear(desc->pending_mask);
  59 #endif
  60 }
  61
  62 static inline int desc_node(struct irq_desc *desc)
  63 {
  64         return desc->irq_data.node;
  65 }
  66
  67 #else
  68 static inline int
  69 alloc_masks(struct irq_desc *desc, gfp_t gfp, int node) { return 0; }
  70 static inline void desc_smp_init(struct irq_desc *desc, int node) { }
  71 static inline int desc_node(struct irq_desc *desc) { return 0; }
  72 #endif
  73
  74 static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
  75                 struct module *owner)
  76 {
  77         int cpu;
  78
  79         desc->irq_data.irq = irq;
  80         desc->irq_data.chip = &no_irq_chip;
  81         desc->irq_data.chip_data = NULL;
  82         desc->irq_data.handler_data = NULL;
  83         desc->irq_data.msi_desc = NULL;
  84         irq_settings_clr_and_set(desc, ~0, _IRQ_DEFAULT_INIT_FLAGS);
  85         irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
  86         desc->handle_irq = handle_bad_irq;
  87         desc->depth = 1;
  88         desc->irq_count = 0;
  89         desc->irqs_unhandled = 0;
  90         desc->name = NULL;
  91         desc->owner = owner;
  92         for_each_possible_cpu(cpu)
  93                 *per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
  94         desc_smp_init(desc, node);
  95 }
  96
  97 int nr_irqs = NR_IRQS;
  98 EXPORT_SYMBOL_GPL(nr_irqs);
  99
 100 static DEFINE_MUTEX(sparse_irq_lock);
 101 static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);
 102
 103 #ifdef CONFIG_SPARSE_IRQ
 104
 105 static RADIX_TREE(irq_desc_tree, GFP_KERNEL);
 106
 107 static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
 108 {
 109         radix_tree_insert(&irq_desc_tree, irq, desc);
 110 }
 111
 112 struct irq_desc *irq_to_desc(unsigned int irq)
 113 {
 114         return radix_tree_lookup(&irq_desc_tree, irq);
 115 }
 116 EXPORT_SYMBOL(irq_to_desc);
 117
 118 static void delete_irq_desc(unsigned int irq)
 119 {
 120         radix_tree_delete(&irq_desc_tree, irq);
 121 }
 122
 123 #ifdef CONFIG_SMP
 124 static void free_masks(struct irq_desc *desc)
 125 {
 126 #ifdef CONFIG_GENERIC_PENDING_IRQ
 127         free_cpumask_var(desc->pending_mask);
 128 #endif
 129         free_cpumask_var(desc->irq_data.affinity);
 130 }
 131 #else
 132 static inline void free_masks(struct irq_desc *desc) { }
 133 #endif
 134
 135 void irq_lock_sparse(void)
 136 {
 137         mutex_lock(&sparse_irq_lock);
 138 }
 139
 140 void irq_unlock_sparse(void)
 141 {
 142         mutex_unlock(&sparse_irq_lock);
 143 }
 144
 145 static struct irq_desc *alloc_desc(int irq, int node, struct module *owner)
 146 {
 147         struct irq_desc *desc;
 148         gfp_t gfp = GFP_KERNEL;
 149
 150         desc = kzalloc_node(sizeof(*desc), gfp, node);
 151         if (!desc)
 152                 return NULL;
 153         /* allocate based on nr_cpu_ids */
 154         desc->kstat_irqs = alloc_percpu(unsigned int);
 155         if (!desc->kstat_irqs)
 156                 goto err_desc;
 157
 158         if (alloc_masks(desc, gfp, node))
 159                 goto err_kstat;
 160
 161         raw_spin_lock_init(&desc->lock);
 162         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 163
 164         desc_set_defaults(irq, desc, node, owner);
 165
 166         return desc;
 167
 168 err_kstat:
 169         free_percpu(desc->kstat_irqs);
 170 err_desc:
 171         kfree(desc);
 172         return NULL;
 173 }
 174
 175 static void free_desc(unsigned int irq)
 176 {
 177         struct irq_desc *desc = irq_to_desc(irq);
 178
 179         unregister_irq_proc(irq, desc);
 180
 181         /*
 182          * sparse_irq_lock protects also show_interrupts() and
 183          * kstat_irq_usr(). Once we deleted the descriptor from the
 184          * sparse tree we can free it. Access in proc will fail to
 185          * lookup the descriptor.
 186          */
 187         mutex_lock(&sparse_irq_lock);
 188         delete_irq_desc(irq);
 189         mutex_unlock(&sparse_irq_lock);
 190
 191         free_masks(desc);
 192         free_percpu(desc->kstat_irqs);
 193         kfree(desc);
 194 }
 195
 196 static int alloc_descs(unsigned int start, unsigned int cnt, int node,
 197                        struct module *owner)
 198 {
 199         struct irq_desc *desc;
 200         int i;
 201
 202         for (i = 0; i < cnt; i++) {
 203                 desc = alloc_desc(start + i, node, owner);
 204                 if (!desc)
 205                         goto err;
 206                 mutex_lock(&sparse_irq_lock);
 207                 irq_insert_desc(start + i, desc);
 208                 mutex_unlock(&sparse_irq_lock);
 209         }
 210         return start;
 211
 212 err:
 213         for (i--; i >= 0; i--)
 214                 free_desc(start + i);
 215
 216         mutex_lock(&sparse_irq_lock);
 217         bitmap_clear(allocated_irqs, start, cnt);
 218         mutex_unlock(&sparse_irq_lock);
 219         return -ENOMEM;
 220 }
 221
 222 static int irq_expand_nr_irqs(unsigned int nr)
 223 {
 224         if (nr > IRQ_BITMAP_BITS)
 225                 return -ENOMEM;
 226         nr_irqs = nr;
 227         return 0;
 228 }
 229
 230 int __init early_irq_init(void)
 231 {
 232         int i, initcnt, node = first_online_node;
 233         struct irq_desc *desc;
 234
 235         init_irq_default_affinity();
 236
 237         /* Let arch update nr_irqs and return the nr of preallocated irqs */
 238         initcnt = arch_probe_nr_irqs();
 239         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d %d\n", NR_IRQS, nr_irqs, initcnt);
 240
 241         if (WARN_ON(nr_irqs > IRQ_BITMAP_BITS))
 242                 nr_irqs = IRQ_BITMAP_BITS;
 243
 244         if (WARN_ON(initcnt > IRQ_BITMAP_BITS))
 245                 initcnt = IRQ_BITMAP_BITS;
 246
 247         if (initcnt > nr_irqs)
 248                 nr_irqs = initcnt;
 249
 250         for (i = 0; i < initcnt; i++) {
 251                 desc = alloc_desc(i, node, NULL);
 252                 set_bit(i, allocated_irqs);
 253                 irq_insert_desc(i, desc);
 254         }
 255         return arch_early_irq_init();
 256 }
 257
 258 #else /* !CONFIG_SPARSE_IRQ */
 259
 260 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 261         [0 ... NR_IRQS-1] = {
 262                 .handle_irq     = handle_bad_irq,
 263                 .depth          = 1,
 264                 .lock           = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
 265         }
 266 };
 267
 268 int __init early_irq_init(void)
 269 {
 270         int count, i, node = first_online_node;
 271         struct irq_desc *desc;
 272
 273         init_irq_default_affinity();
 274
 275         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 276
 277         desc = irq_desc;
 278         count = ARRAY_SIZE(irq_desc);
 279
 280         for (i = 0; i < count; i++) {
 281                 desc[i].kstat_irqs = alloc_percpu(unsigned int);
 282                 alloc_masks(&desc[i], GFP_KERNEL, node);
 283                 raw_spin_lock_init(&desc[i].lock);
 284                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 285                 desc_set_defaults(i, &desc[i], node, NULL);
 286         }
 287         return arch_early_irq_init();
 288 }
 289
 290 struct irq_desc *irq_to_desc(unsigned int irq)
 291 {
 292         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 293 }
 294 EXPORT_SYMBOL(irq_to_desc);
 295
 296 static void free_desc(unsigned int irq)
 297 {
 298         struct irq_desc *desc = irq_to_desc(irq);
 299         unsigned long flags;
 300
 301         raw_spin_lock_irqsave(&desc->lock, flags);
 302         desc_set_defaults(irq, desc, desc_node(desc), NULL);
 303         raw_spin_unlock_irqrestore(&desc->lock, flags);
 304 }
 305
 306 static inline int alloc_descs(unsigned int start, unsigned int cnt, int node,
 307                               struct module *owner)
 308 {
 309         u32 i;
 310
 311         for (i = 0; i < cnt; i++) {
 312                 struct irq_desc *desc = irq_to_desc(start + i);
 313
 314                 desc->owner = owner;
 315         }
 316         return start;
 317 }
 318
 319 static int irq_expand_nr_irqs(unsigned int nr)
 320 {
 321         return -ENOMEM;
 322 }
 323
 324 void irq_mark_irq(unsigned int irq)
 325 {
 326         mutex_lock(&sparse_irq_lock);
 327         bitmap_set(allocated_irqs, irq, 1);
 328         mutex_unlock(&sparse_irq_lock);
 329 }
 330
 331 #ifdef CONFIG_GENERIC_IRQ_LEGACY
 332 void irq_init_desc(unsigned int irq)
 333 {
 334         free_desc(irq);
 335 }
 336 #endif
 337
 338 #endif /* !CONFIG_SPARSE_IRQ */
 339
 340 /**
 341  * generic_handle_irq - Invoke the handler for a particular irq
 342  * @irq:        The irq number to handle
 343  *
 344  */
 345 int generic_handle_irq(unsigned int irq)
 346 {
 347         struct irq_desc *desc = irq_to_desc(irq);
 348
 349         if (!desc)
 350                 return -EINVAL;
 351         generic_handle_irq_desc(irq, desc);
 352         return 0;
 353 }
 354 EXPORT_SYMBOL_GPL(generic_handle_irq);
 355
 356 #ifdef CONFIG_HANDLE_DOMAIN_IRQ
 357 /**
 358  * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain
 359  * @domain:     The domain where to perform the lookup
 360  * @hwirq:      The HW irq number to convert to a logical one
 361  * @lookup:     Whether to perform the domain lookup or not
 362  * @regs:       Register file coming from the low-level handling code
 363  *
 364  * Returns:     0 on success, or -EINVAL if conversion has failed
 365  */
 366 int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
 367                         bool lookup, struct pt_regs *regs)
 368 {
 369         struct pt_regs *old_regs = set_irq_regs(regs);
 370         unsigned int irq = hwirq;
 371         int ret = 0;
 372
 373         irq_enter();
 374
 375 #ifdef CONFIG_IRQ_DOMAIN
 376         if (lookup)
 377                 irq = irq_find_mapping(domain, hwirq);
 378 #endif
 379
 380         /*
 381          * Some hardware gives randomly wrong interrupts.  Rather
 382          * than crashing, do something sensible.
 383          */
 384         if (unlikely(!irq || irq >= nr_irqs)) {
 385                 ack_bad_irq(irq);
 386                 ret = -EINVAL;
 387         } else {
 388                 generic_handle_irq(irq);
 389         }
 390
 391         irq_exit();
 392         set_irq_regs(old_regs);
 393         return ret;
 394 }
 395 #endif
 396
 397 /* Dynamic interrupt handling */
 398
 399 /**
 400  * irq_free_descs - free irq descriptors
 401  * @from:       Start of descriptor range
 402  * @cnt:        Number of consecutive irqs to free
 403  */
 404 void irq_free_descs(unsigned int from, unsigned int cnt)
 405 {
 406         int i;
 407
 408         if (from >= nr_irqs || (from + cnt) > nr_irqs)
 409                 return;
 410
 411         for (i = 0; i < cnt; i++)
 412                 free_desc(from + i);
 413
 414         mutex_lock(&sparse_irq_lock);
 415         bitmap_clear(allocated_irqs, from, cnt);
 416         mutex_unlock(&sparse_irq_lock);
 417 }
 418 EXPORT_SYMBOL_GPL(irq_free_descs);
 419
 420 /**
 421  * irq_alloc_descs - allocate and initialize a range of irq descriptors
 422  * @irq:        Allocate for specific irq number if irq >= 0
 423  * @from:       Start the search from this irq number
 424  * @cnt:        Number of consecutive irqs to allocate.
 425  * @node:       Preferred node on which the irq descriptor should be allocated
 426  * @owner:      Owning module (can be NULL)
 427  *
 428  * Returns the first irq number or error code
 429  */
 430 int __ref
 431 __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
 432                   struct module *owner)
 433 {
 434         int start, ret;
 435
 436         if (!cnt)
 437                 return -EINVAL;
 438
 439         if (irq >= 0) {
 440                 if (from > irq)
 441                         return -EINVAL;
 442                 from = irq;
 443         } else {
 444                 /*
 445                  * For interrupts which are freely allocated the
 446                  * architecture can force a lower bound to the @from
 447                  * argument. x86 uses this to exclude the GSI space.
 448                  */
 449                 from = arch_dynirq_lower_bound(from);
 450         }
 451
 452         mutex_lock(&sparse_irq_lock);
 453
 454         start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS,
 455                                            from, cnt, 0);
 456         ret = -EEXIST;
 457         if (irq >=0 && start != irq)
 458                 goto err;
 459
 460         if (start + cnt > nr_irqs) {
 461                 ret = irq_expand_nr_irqs(start + cnt);
 462                 if (ret)
 463                         goto err;
 464         }
 465
 466         bitmap_set(allocated_irqs, start, cnt);
 467         mutex_unlock(&sparse_irq_lock);
 468         return alloc_descs(start, cnt, node, owner);
 469
 470 err:
 471         mutex_unlock(&sparse_irq_lock);
 472         return ret;
 473 }
 474 EXPORT_SYMBOL_GPL(__irq_alloc_descs);
 475
 476 #ifdef CONFIG_GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
 477 /**
 478  * irq_alloc_hwirqs - Allocate an irq descriptor and initialize the hardware
 479  * @cnt:        number of interrupts to allocate
 480  * @node:       node on which to allocate
 481  *
 482  * Returns an interrupt number > 0 or 0, if the allocation fails.
 483  */
 484 unsigned int irq_alloc_hwirqs(int cnt, int node)
 485 {
 486         int i, irq = __irq_alloc_descs(-1, 0, cnt, node, NULL);
 487
 488         if (irq < 0)
 489                 return 0;
 490
 491         for (i = irq; cnt > 0; i++, cnt--) {
 492                 if (arch_setup_hwirq(i, node))
 493                         goto err;
 494                 irq_clear_status_flags(i, _IRQ_NOREQUEST);
 495         }
 496         return irq;
 497
 498 err:
 499         for (i--; i >= irq; i--) {
 500                 irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE);
 501                 arch_teardown_hwirq(i);
 502         }
 503         irq_free_descs(irq, cnt);
 504         return 0;
 505 }
 506 EXPORT_SYMBOL_GPL(irq_alloc_hwirqs);
 507
 508 /**
 509  * irq_free_hwirqs - Free irq descriptor and cleanup the hardware
 510  * @from:       Free from irq number
 511  * @cnt:        number of interrupts to free
 512  *
 513  */
 514 void irq_free_hwirqs(unsigned int from, int cnt)
 515 {
 516         int i, j;
 517
 518         for (i = from, j = cnt; j > 0; i++, j--) {
 519                 irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE);
 520                 arch_teardown_hwirq(i);
 521         }
 522         irq_free_descs(from, cnt);
 523 }
 524 EXPORT_SYMBOL_GPL(irq_free_hwirqs);
 525 #endif
 526
 527 /**
 528  * irq_get_next_irq - get next allocated irq number
 529  * @offset:     where to start the search
 530  *
 531  * Returns next irq number after offset or nr_irqs if none is found.
 532  */
 533 unsigned int irq_get_next_irq(unsigned int offset)
 534 {
 535         return find_next_bit(allocated_irqs, nr_irqs, offset);
 536 }
 537
 538 struct irq_desc *
 539 __irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
 540                     unsigned int check)
 541 {
 542         struct irq_desc *desc = irq_to_desc(irq);
 543
 544         if (desc) {
 545                 if (check & _IRQ_DESC_CHECK) {
 546                         if ((check & _IRQ_DESC_PERCPU) &&
 547                             !irq_settings_is_per_cpu_devid(desc))
 548                                 return NULL;
 549
 550                         if (!(check & _IRQ_DESC_PERCPU) &&
 551                             irq_settings_is_per_cpu_devid(desc))
 552                                 return NULL;
 553                 }
 554
 555                 if (bus)
 556                         chip_bus_lock(desc);
 557                 raw_spin_lock_irqsave(&desc->lock, *flags);
 558         }
 559         return desc;
 560 }
 561
 562 void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus)
 563 {
 564         raw_spin_unlock_irqrestore(&desc->lock, flags);
 565         if (bus)
 566                 chip_bus_sync_unlock(desc);
 567 }
 568
 569 int irq_set_percpu_devid(unsigned int irq)
 570 {
 571         struct irq_desc *desc = irq_to_desc(irq);
 572
 573         if (!desc)
 574                 return -EINVAL;
 575
 576         if (desc->percpu_enabled)
 577                 return -EINVAL;
 578
 579         desc->percpu_enabled = kzalloc(sizeof(*desc->percpu_enabled), GFP_KERNEL);
 580
 581         if (!desc->percpu_enabled)
 582                 return -ENOMEM;
 583
 584         irq_set_percpu_devid_flags(irq);
 585         return 0;
 586 }
 587
 588 void kstat_incr_irq_this_cpu(unsigned int irq)
 589 {
 590         kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
 591 }
 592
 593 /**
 594  * kstat_irqs_cpu - Get the statistics for an interrupt on a cpu
 595  * @irq:        The interrupt number
 596  * @cpu:        The cpu number
 597  *
 598  * Returns the sum of interrupt counts on @cpu since boot for
 599  * @irq. The caller must ensure that the interrupt is not removed
 600  * concurrently.
 601  */
 602 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 603 {
 604         struct irq_desc *desc = irq_to_desc(irq);
 605
 606         return desc && desc->kstat_irqs ?
 607                         *per_cpu_ptr(desc->kstat_irqs, cpu) : 0;
 608 }
 609
 610 /**
 611  * kstat_irqs - Get the statistics for an interrupt
 612  * @irq:        The interrupt number
 613  *
 614  * Returns the sum of interrupt counts on all cpus since boot for
 615  * @irq. The caller must ensure that the interrupt is not removed
 616  * concurrently.
 617  */
 618 unsigned int kstat_irqs(unsigned int irq)
 619 {
 620         struct irq_desc *desc = irq_to_desc(irq);
 621         int cpu;
 622         int sum = 0;
 623
 624         if (!desc || !desc->kstat_irqs)
 625                 return 0;
 626         for_each_possible_cpu(cpu)
 627                 sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
 628         return sum;
 629 }
 630
 631 /**
 632  * kstat_irqs_usr - Get the statistics for an interrupt
 633  * @irq:        The interrupt number
 634  *
 635  * Returns the sum of interrupt counts on all cpus since boot for
 636  * @irq. Contrary to kstat_irqs() this can be called from any
 637  * preemptible context. It's protected against concurrent removal of
 638  * an interrupt descriptor when sparse irqs are enabled.
 639  */
 640 unsigned int kstat_irqs_usr(unsigned int irq)
 641 {
 642         int sum;
 643
 644         irq_lock_sparse();
 645         sum = kstat_irqs(irq);
 646         irq_unlock_sparse();
 647         return sum;
 648 }