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