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/module.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/kernel_stat.h>
  15 #include <linux/radix-tree.h>
  16 #include <linux/bitmap.h>
  17
  18 #include "internals.h"
  19
  20 /*
  21  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  22  */
  23 static struct lock_class_key irq_desc_lock_class;
  24
  25 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
  26 static void __init init_irq_default_affinity(void)
  27 {
  28         alloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
  29         cpumask_setall(irq_default_affinity);
  30 }
  31 #else
  32 static void __init init_irq_default_affinity(void)
  33 {
  34 }
  35 #endif
  36
  37 #ifdef CONFIG_SMP
  38 static int alloc_masks(struct irq_desc *desc, gfp_t gfp, int node)
  39 {
  40         if (!zalloc_cpumask_var_node(&desc->irq_data.affinity, gfp, node))
  41                 return -ENOMEM;
  42
  43 #ifdef CONFIG_GENERIC_PENDING_IRQ
  44         if (!zalloc_cpumask_var_node(&desc->pending_mask, gfp, node)) {
  45                 free_cpumask_var(desc->irq_data.affinity);
  46                 return -ENOMEM;
  47         }
  48 #endif
  49         return 0;
  50 }
  51
  52 static void desc_smp_init(struct irq_desc *desc, int node)
  53 {
  54         desc->irq_data.node = node;
  55         cpumask_copy(desc->irq_data.affinity, irq_default_affinity);
  56 #ifdef CONFIG_GENERIC_PENDING_IRQ
  57         cpumask_clear(desc->pending_mask);
  58 #endif
  59 }
  60
  61 static inline int desc_node(struct irq_desc *desc)
  62 {
  63         return desc->irq_data.node;
  64 }
  65
  66 #else
  67 static inline int
  68 alloc_masks(struct irq_desc *desc, gfp_t gfp, int node) { return 0; }
  69 static inline void desc_smp_init(struct irq_desc *desc, int node) { }
  70 static inline int desc_node(struct irq_desc *desc) { return 0; }
  71 #endif
  72
  73 static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node)
  74 {
  75         int cpu;
  76
  77         desc->irq_data.irq = irq;
  78         desc->irq_data.chip = &no_irq_chip;
  79         desc->irq_data.chip_data = NULL;
  80         desc->irq_data.handler_data = NULL;
  81         desc->irq_data.msi_desc = NULL;
  82         desc->status = IRQ_DEFAULT_INIT_FLAGS;
  83         desc->handle_irq = handle_bad_irq;
  84         desc->depth = 1;
  85         desc->irq_count = 0;
  86         desc->irqs_unhandled = 0;
  87         desc->name = NULL;
  88         for_each_possible_cpu(cpu)
  89                 *per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
  90         desc_smp_init(desc, node);
  91 }
  92
  93 int nr_irqs = NR_IRQS;
  94 EXPORT_SYMBOL_GPL(nr_irqs);
  95
  96 static DEFINE_MUTEX(sparse_irq_lock);
  97 static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);
  98
  99 #ifdef CONFIG_SPARSE_IRQ
 100
 101 static RADIX_TREE(irq_desc_tree, GFP_KERNEL);
 102
 103 static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
 104 {
 105         radix_tree_insert(&irq_desc_tree, irq, desc);
 106 }
 107
 108 struct irq_desc *irq_to_desc(unsigned int irq)
 109 {
 110         return radix_tree_lookup(&irq_desc_tree, irq);
 111 }
 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 static struct irq_desc *alloc_desc(int irq, int node)
 131 {
 132         struct irq_desc *desc;
 133         gfp_t gfp = GFP_KERNEL;
 134
 135         desc = kzalloc_node(sizeof(*desc), gfp, node);
 136         if (!desc)
 137                 return NULL;
 138         /* allocate based on nr_cpu_ids */
 139         desc->kstat_irqs = alloc_percpu(unsigned int);
 140         if (!desc->kstat_irqs)
 141                 goto err_desc;
 142
 143         if (alloc_masks(desc, gfp, node))
 144                 goto err_kstat;
 145
 146         raw_spin_lock_init(&desc->lock);
 147         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 148
 149         desc_set_defaults(irq, desc, node);
 150
 151         return desc;
 152
 153 err_kstat:
 154         free_percpu(desc->kstat_irqs);
 155 err_desc:
 156         kfree(desc);
 157         return NULL;
 158 }
 159
 160 static void free_desc(unsigned int irq)
 161 {
 162         struct irq_desc *desc = irq_to_desc(irq);
 163
 164         unregister_irq_proc(irq, desc);
 165
 166         mutex_lock(&sparse_irq_lock);
 167         delete_irq_desc(irq);
 168         mutex_unlock(&sparse_irq_lock);
 169
 170         free_masks(desc);
 171         free_percpu(desc->kstat_irqs);
 172         kfree(desc);
 173 }
 174
 175 static int alloc_descs(unsigned int start, unsigned int cnt, int node)
 176 {
 177         struct irq_desc *desc;
 178         int i;
 179
 180         for (i = 0; i < cnt; i++) {
 181                 desc = alloc_desc(start + i, node);
 182                 if (!desc)
 183                         goto err;
 184                 mutex_lock(&sparse_irq_lock);
 185                 irq_insert_desc(start + i, desc);
 186                 mutex_unlock(&sparse_irq_lock);
 187         }
 188         return start;
 189
 190 err:
 191         for (i--; i >= 0; i--)
 192                 free_desc(start + i);
 193
 194         mutex_lock(&sparse_irq_lock);
 195         bitmap_clear(allocated_irqs, start, cnt);
 196         mutex_unlock(&sparse_irq_lock);
 197         return -ENOMEM;
 198 }
 199
 200 struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
 201 {
 202         int res = irq_alloc_descs(irq, irq, 1, node);
 203
 204         if (res == -EEXIST || res == irq)
 205                 return irq_to_desc(irq);
 206         return NULL;
 207 }
 208
 209 int __init early_irq_init(void)
 210 {
 211         int i, initcnt, node = first_online_node;
 212         struct irq_desc *desc;
 213
 214         init_irq_default_affinity();
 215
 216         /* Let arch update nr_irqs and return the nr of preallocated irqs */
 217         initcnt = arch_probe_nr_irqs();
 218         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d %d\n", NR_IRQS, nr_irqs, initcnt);
 219
 220         if (WARN_ON(nr_irqs > IRQ_BITMAP_BITS))
 221                 nr_irqs = IRQ_BITMAP_BITS;
 222
 223         if (WARN_ON(initcnt > IRQ_BITMAP_BITS))
 224                 initcnt = IRQ_BITMAP_BITS;
 225
 226         if (initcnt > nr_irqs)
 227                 nr_irqs = initcnt;
 228
 229         for (i = 0; i < initcnt; i++) {
 230                 desc = alloc_desc(i, node);
 231                 set_bit(i, allocated_irqs);
 232                 irq_insert_desc(i, desc);
 233         }
 234         return arch_early_irq_init();
 235 }
 236
 237 #else /* !CONFIG_SPARSE_IRQ */
 238
 239 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 240         [0 ... NR_IRQS-1] = {
 241                 .status         = IRQ_DEFAULT_INIT_FLAGS,
 242                 .handle_irq     = handle_bad_irq,
 243                 .depth          = 1,
 244                 .lock           = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
 245         }
 246 };
 247
 248 int __init early_irq_init(void)
 249 {
 250         int count, i, node = first_online_node;
 251         struct irq_desc *desc;
 252
 253         init_irq_default_affinity();
 254
 255         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 256
 257         desc = irq_desc;
 258         count = ARRAY_SIZE(irq_desc);
 259
 260         for (i = 0; i < count; i++) {
 261                 desc[i].irq_data.irq = i;
 262                 desc[i].irq_data.chip = &no_irq_chip;
 263                 /* TODO : do this allocation on-demand ... */
 264                 desc[i].kstat_irqs = alloc_percpu(unsigned int);
 265                 alloc_masks(desc + i, GFP_KERNEL, node);
 266                 desc_smp_init(desc + i, node);
 267                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 268         }
 269         return arch_early_irq_init();
 270 }
 271
 272 struct irq_desc *irq_to_desc(unsigned int irq)
 273 {
 274         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 275 }
 276
 277 struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)
 278 {
 279         return irq_to_desc(irq);
 280 }
 281
 282 static void free_desc(unsigned int irq)
 283 {
 284         dynamic_irq_cleanup(irq);
 285 }
 286
 287 static inline int alloc_descs(unsigned int start, unsigned int cnt, int node)
 288 {
 289 #if defined(CONFIG_KSTAT_IRQS_ONDEMAND)
 290         struct irq_desc *desc;
 291         unsigned int i;
 292
 293         for (i = 0; i < cnt; i++) {
 294                 desc = irq_to_desc(start + i);
 295                 if (desc && !desc->kstat_irqs) {
 296                         unsigned int __percpu *stats = alloc_percpu(unsigned int);
 297
 298                         if (!stats)
 299                                 return -1;
 300                         if (cmpxchg(&desc->kstat_irqs, NULL, stats) != NULL)
 301                                 free_percpu(stats);
 302                 }
 303         }
 304 #endif
 305         return start;
 306 }
 307 #endif /* !CONFIG_SPARSE_IRQ */
 308
 309 /* Dynamic interrupt handling */
 310
 311 /**
 312  * irq_free_descs - free irq descriptors
 313  * @from:       Start of descriptor range
 314  * @cnt:        Number of consecutive irqs to free
 315  */
 316 void irq_free_descs(unsigned int from, unsigned int cnt)
 317 {
 318         int i;
 319
 320         if (from >= nr_irqs || (from + cnt) > nr_irqs)
 321                 return;
 322
 323         for (i = 0; i < cnt; i++)
 324                 free_desc(from + i);
 325
 326         mutex_lock(&sparse_irq_lock);
 327         bitmap_clear(allocated_irqs, from, cnt);
 328         mutex_unlock(&sparse_irq_lock);
 329 }
 330
 331 /**
 332  * irq_alloc_descs - allocate and initialize a range of irq descriptors
 333  * @irq:        Allocate for specific irq number if irq >= 0
 334  * @from:       Start the search from this irq number
 335  * @cnt:        Number of consecutive irqs to allocate.
 336  * @node:       Preferred node on which the irq descriptor should be allocated
 337  *
 338  * Returns the first irq number or error code
 339  */
 340 int __ref
 341 irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node)
 342 {
 343         int start, ret;
 344
 345         if (!cnt)
 346                 return -EINVAL;
 347
 348         mutex_lock(&sparse_irq_lock);
 349
 350         start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
 351         ret = -EEXIST;
 352         if (irq >=0 && start != irq)
 353                 goto err;
 354
 355         ret = -ENOMEM;
 356         if (start >= nr_irqs)
 357                 goto err;
 358
 359         bitmap_set(allocated_irqs, start, cnt);
 360         mutex_unlock(&sparse_irq_lock);
 361         return alloc_descs(start, cnt, node);
 362
 363 err:
 364         mutex_unlock(&sparse_irq_lock);
 365         return ret;
 366 }
 367
 368 /**
 369  * irq_reserve_irqs - mark irqs allocated
 370  * @from:       mark from irq number
 371  * @cnt:        number of irqs to mark
 372  *
 373  * Returns 0 on success or an appropriate error code
 374  */
 375 int irq_reserve_irqs(unsigned int from, unsigned int cnt)
 376 {
 377         unsigned int start;
 378         int ret = 0;
 379
 380         if (!cnt || (from + cnt) > nr_irqs)
 381                 return -EINVAL;
 382
 383         mutex_lock(&sparse_irq_lock);
 384         start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
 385         if (start == from)
 386                 bitmap_set(allocated_irqs, start, cnt);
 387         else
 388                 ret = -EEXIST;
 389         mutex_unlock(&sparse_irq_lock);
 390         return ret;
 391 }
 392
 393 /**
 394  * irq_get_next_irq - get next allocated irq number
 395  * @offset:     where to start the search
 396  *
 397  * Returns next irq number after offset or nr_irqs if none is found.
 398  */
 399 unsigned int irq_get_next_irq(unsigned int offset)
 400 {
 401         return find_next_bit(allocated_irqs, nr_irqs, offset);
 402 }
 403
 404 /**
 405  * dynamic_irq_cleanup - cleanup a dynamically allocated irq
 406  * @irq:        irq number to initialize
 407  */
 408 void dynamic_irq_cleanup(unsigned int irq)
 409 {
 410         struct irq_desc *desc = irq_to_desc(irq);
 411         unsigned long flags;
 412
 413         raw_spin_lock_irqsave(&desc->lock, flags);
 414         desc_set_defaults(irq, desc, desc_node(desc));
 415         raw_spin_unlock_irqrestore(&desc->lock, flags);
 416 }
 417
 418 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 419 {
 420         struct irq_desc *desc = irq_to_desc(irq);
 421
 422         return desc && desc->kstat_irqs ?
 423                         *per_cpu_ptr(desc->kstat_irqs, cpu) : 0;
 424 }
 425
 426 #ifdef CONFIG_GENERIC_HARDIRQS
 427 unsigned int kstat_irqs(unsigned int irq)
 428 {
 429         struct irq_desc *desc = irq_to_desc(irq);
 430         int cpu;
 431         int sum = 0;
 432
 433         if (!desc || !desc->kstat_irqs)
 434                 return 0;
 435         for_each_possible_cpu(cpu)
 436                 sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
 437         return sum;
 438 }
 439 #endif /* CONFIG_GENERIC_HARDIRQS */