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