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         irq_settings_clr_and_set(desc, ~0, _IRQ_DEFAULT_INIT_FLAGS);
  83         irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
  84         desc->handle_irq = handle_bad_irq;
  85         desc->depth = 1;
  86         desc->irq_count = 0;
  87         desc->irqs_unhandled = 0;
  88         desc->name = NULL;
  89         for_each_possible_cpu(cpu)
  90                 *per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
  91         desc_smp_init(desc, node);
  92 }
  93
  94 int nr_irqs = NR_IRQS;
  95 EXPORT_SYMBOL_GPL(nr_irqs);
  96
  97 static DEFINE_MUTEX(sparse_irq_lock);
  98 static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);
  99
 100 #ifdef CONFIG_SPARSE_IRQ
 101
 102 static RADIX_TREE(irq_desc_tree, GFP_KERNEL);
 103
 104 static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
 105 {
 106         radix_tree_insert(&irq_desc_tree, irq, desc);
 107 }
 108
 109 struct irq_desc *irq_to_desc(unsigned int irq)
 110 {
 111         return radix_tree_lookup(&irq_desc_tree, irq);
 112 }
 113
 114 static void delete_irq_desc(unsigned int irq)
 115 {
 116         radix_tree_delete(&irq_desc_tree, irq);
 117 }
 118
 119 #ifdef CONFIG_SMP
 120 static void free_masks(struct irq_desc *desc)
 121 {
 122 #ifdef CONFIG_GENERIC_PENDING_IRQ
 123         free_cpumask_var(desc->pending_mask);
 124 #endif
 125         free_cpumask_var(desc->irq_data.affinity);
 126 }
 127 #else
 128 static inline void free_masks(struct irq_desc *desc) { }
 129 #endif
 130
 131 static struct irq_desc *alloc_desc(int irq, int node)
 132 {
 133         struct irq_desc *desc;
 134         gfp_t gfp = GFP_KERNEL;
 135
 136         desc = kzalloc_node(sizeof(*desc), gfp, node);
 137         if (!desc)
 138                 return NULL;
 139         /* allocate based on nr_cpu_ids */
 140         desc->kstat_irqs = alloc_percpu(unsigned int);
 141         if (!desc->kstat_irqs)
 142                 goto err_desc;
 143
 144         if (alloc_masks(desc, gfp, node))
 145                 goto err_kstat;
 146
 147         raw_spin_lock_init(&desc->lock);
 148         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 149
 150         desc_set_defaults(irq, desc, node);
 151
 152         return desc;
 153
 154 err_kstat:
 155         free_percpu(desc->kstat_irqs);
 156 err_desc:
 157         kfree(desc);
 158         return NULL;
 159 }
 160
 161 static void free_desc(unsigned int irq)
 162 {
 163         struct irq_desc *desc = irq_to_desc(irq);
 164
 165         unregister_irq_proc(irq, desc);
 166
 167         mutex_lock(&sparse_irq_lock);
 168         delete_irq_desc(irq);
 169         mutex_unlock(&sparse_irq_lock);
 170
 171         free_masks(desc);
 172         free_percpu(desc->kstat_irqs);
 173         kfree(desc);
 174 }
 175
 176 static int alloc_descs(unsigned int start, unsigned int cnt, int node)
 177 {
 178         struct irq_desc *desc;
 179         int i;
 180
 181         for (i = 0; i < cnt; i++) {
 182                 desc = alloc_desc(start + i, node);
 183                 if (!desc)
 184                         goto err;
 185                 mutex_lock(&sparse_irq_lock);
 186                 irq_insert_desc(start + i, desc);
 187                 mutex_unlock(&sparse_irq_lock);
 188         }
 189         return start;
 190
 191 err:
 192         for (i--; i >= 0; i--)
 193                 free_desc(start + i);
 194
 195         mutex_lock(&sparse_irq_lock);
 196         bitmap_clear(allocated_irqs, start, cnt);
 197         mutex_unlock(&sparse_irq_lock);
 198         return -ENOMEM;
 199 }
 200
 201 static int irq_expand_nr_irqs(unsigned int nr)
 202 {
 203         if (nr > IRQ_BITMAP_BITS)
 204                 return -ENOMEM;
 205         nr_irqs = nr;
 206         return 0;
 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                 .handle_irq     = handle_bad_irq,
 242                 .depth          = 1,
 243                 .lock           = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
 244         }
 245 };
 246
 247 int __init early_irq_init(void)
 248 {
 249         int count, i, node = first_online_node;
 250         struct irq_desc *desc;
 251
 252         init_irq_default_affinity();
 253
 254         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 255
 256         desc = irq_desc;
 257         count = ARRAY_SIZE(irq_desc);
 258
 259         for (i = 0; i < count; i++) {
 260                 desc[i].irq_data.irq = i;
 261                 desc[i].irq_data.chip = &no_irq_chip;
 262                 desc[i].kstat_irqs = alloc_percpu(unsigned int);
 263                 irq_settings_clr_and_set(desc, ~0, _IRQ_DEFAULT_INIT_FLAGS);
 264                 alloc_masks(desc + i, GFP_KERNEL, node);
 265                 desc_smp_init(desc + i, node);
 266                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 267         }
 268         return arch_early_irq_init();
 269 }
 270
 271 struct irq_desc *irq_to_desc(unsigned int irq)
 272 {
 273         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 274 }
 275
 276 static void free_desc(unsigned int irq)
 277 {
 278         dynamic_irq_cleanup(irq);
 279 }
 280
 281 static inline int alloc_descs(unsigned int start, unsigned int cnt, int node)
 282 {
 283         return start;
 284 }
 285
 286 static int irq_expand_nr_irqs(unsigned int nr)
 287 {
 288         return -ENOMEM;
 289 }
 290
 291 #endif /* !CONFIG_SPARSE_IRQ */
 292
 293 /* Dynamic interrupt handling */
 294
 295 /**
 296  * irq_free_descs - free irq descriptors
 297  * @from:       Start of descriptor range
 298  * @cnt:        Number of consecutive irqs to free
 299  */
 300 void irq_free_descs(unsigned int from, unsigned int cnt)
 301 {
 302         int i;
 303
 304         if (from >= nr_irqs || (from + cnt) > nr_irqs)
 305                 return;
 306
 307         for (i = 0; i < cnt; i++)
 308                 free_desc(from + i);
 309
 310         mutex_lock(&sparse_irq_lock);
 311         bitmap_clear(allocated_irqs, from, cnt);
 312         mutex_unlock(&sparse_irq_lock);
 313 }
 314
 315 /**
 316  * irq_alloc_descs - allocate and initialize a range of irq descriptors
 317  * @irq:        Allocate for specific irq number if irq >= 0
 318  * @from:       Start the search from this irq number
 319  * @cnt:        Number of consecutive irqs to allocate.
 320  * @node:       Preferred node on which the irq descriptor should be allocated
 321  *
 322  * Returns the first irq number or error code
 323  */
 324 int __ref
 325 irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node)
 326 {
 327         int start, ret;
 328
 329         if (!cnt)
 330                 return -EINVAL;
 331
 332         mutex_lock(&sparse_irq_lock);
 333
 334         start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS,
 335                                            from, cnt, 0);
 336         ret = -EEXIST;
 337         if (irq >=0 && start != irq)
 338                 goto err;
 339
 340         if (start + cnt > nr_irqs) {
 341                 ret = irq_expand_nr_irqs(start + cnt);
 342                 if (ret)
 343                         goto err;
 344         }
 345
 346         bitmap_set(allocated_irqs, start, cnt);
 347         mutex_unlock(&sparse_irq_lock);
 348         return alloc_descs(start, cnt, node);
 349
 350 err:
 351         mutex_unlock(&sparse_irq_lock);
 352         return ret;
 353 }
 354
 355 /**
 356  * irq_reserve_irqs - mark irqs allocated
 357  * @from:       mark from irq number
 358  * @cnt:        number of irqs to mark
 359  *
 360  * Returns 0 on success or an appropriate error code
 361  */
 362 int irq_reserve_irqs(unsigned int from, unsigned int cnt)
 363 {
 364         unsigned int start;
 365         int ret = 0;
 366
 367         if (!cnt || (from + cnt) > nr_irqs)
 368                 return -EINVAL;
 369
 370         mutex_lock(&sparse_irq_lock);
 371         start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
 372         if (start == from)
 373                 bitmap_set(allocated_irqs, start, cnt);
 374         else
 375                 ret = -EEXIST;
 376         mutex_unlock(&sparse_irq_lock);
 377         return ret;
 378 }
 379
 380 /**
 381  * irq_get_next_irq - get next allocated irq number
 382  * @offset:     where to start the search
 383  *
 384  * Returns next irq number after offset or nr_irqs if none is found.
 385  */
 386 unsigned int irq_get_next_irq(unsigned int offset)
 387 {
 388         return find_next_bit(allocated_irqs, nr_irqs, offset);
 389 }
 390
 391 struct irq_desc *
 392 __irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus)
 393 {
 394         struct irq_desc *desc = irq_to_desc(irq);
 395
 396         if (desc) {
 397                 if (bus)
 398                         chip_bus_lock(desc);
 399                 raw_spin_lock_irqsave(&desc->lock, *flags);
 400         }
 401         return desc;
 402 }
 403
 404 void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus)
 405 {
 406         raw_spin_unlock_irqrestore(&desc->lock, flags);
 407         if (bus)
 408                 chip_bus_sync_unlock(desc);
 409 }
 410
 411 /**
 412  * dynamic_irq_cleanup - cleanup a dynamically allocated irq
 413  * @irq:        irq number to initialize
 414  */
 415 void dynamic_irq_cleanup(unsigned int irq)
 416 {
 417         struct irq_desc *desc = irq_to_desc(irq);
 418         unsigned long flags;
 419
 420         raw_spin_lock_irqsave(&desc->lock, flags);
 421         desc_set_defaults(irq, desc, desc_node(desc));
 422         raw_spin_unlock_irqrestore(&desc->lock, flags);
 423 }
 424
 425 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 426 {
 427         struct irq_desc *desc = irq_to_desc(irq);
 428
 429         return desc && desc->kstat_irqs ?
 430                         *per_cpu_ptr(desc->kstat_irqs, cpu) : 0;
 431 }
 432
 433 #ifdef CONFIG_GENERIC_HARDIRQS
 434 unsigned int kstat_irqs(unsigned int irq)
 435 {
 436         struct irq_desc *desc = irq_to_desc(irq);
 437         int cpu;
 438         int sum = 0;
 439
 440         if (!desc || !desc->kstat_irqs)
 441                 return 0;
 442         for_each_possible_cpu(cpu)
 443                 sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
 444         return sum;
 445 }
 446 #endif /* CONFIG_GENERIC_HARDIRQS */