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   1 /*
   2  * Copyright (C) 2008 Advanced Micro Devices, Inc.
   3  *
   4  * Author: Joerg Roedel <joerg.roedel@amd.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  18  */
  19
  20 #include <linux/scatterlist.h>
  21 #include <linux/dma-mapping.h>
  22 #include <linux/dma-debug.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/debugfs.h>
  25 #include <linux/device.h>
  26 #include <linux/types.h>
  27 #include <linux/sched.h>
  28 #include <linux/list.h>
  29 #include <linux/slab.h>
  30
  31 #define HASH_SIZE       1024ULL
  32 #define HASH_FN_SHIFT   13
  33 #define HASH_FN_MASK    (HASH_SIZE - 1)
  34
  35 enum {
  36         dma_debug_single,
  37         dma_debug_page,
  38         dma_debug_sg,
  39         dma_debug_coherent,
  40 };
  41
  42 struct dma_debug_entry {
  43         struct list_head list;
  44         struct device    *dev;
  45         int              type;
  46         phys_addr_t      paddr;
  47         u64              dev_addr;
  48         u64              size;
  49         int              direction;
  50         int              sg_call_ents;
  51         int              sg_mapped_ents;
  52 };
  53
  54 struct hash_bucket {
  55         struct list_head list;
  56         spinlock_t lock;
  57 } ____cacheline_aligned_in_smp;
  58
  59 /* Hash list to save the allocated dma addresses */
  60 static struct hash_bucket dma_entry_hash[HASH_SIZE];
  61 /* List of pre-allocated dma_debug_entry's */
  62 static LIST_HEAD(free_entries);
  63 /* Lock for the list above */
  64 static DEFINE_SPINLOCK(free_entries_lock);
  65
  66 /* Global disable flag - will be set in case of an error */
  67 static bool global_disable __read_mostly;
  68
  69 /* Global error count */
  70 static u32 error_count;
  71
  72 /* Global error show enable*/
  73 static u32 show_all_errors __read_mostly;
  74 /* Number of errors to show */
  75 static u32 show_num_errors = 1;
  76
  77 static u32 num_free_entries;
  78 static u32 min_free_entries;
  79
  80 /* number of preallocated entries requested by kernel cmdline */
  81 static u32 req_entries;
  82
  83 /* debugfs dentry's for the stuff above */
  84 static struct dentry *dma_debug_dent        __read_mostly;
  85 static struct dentry *global_disable_dent   __read_mostly;
  86 static struct dentry *error_count_dent      __read_mostly;
  87 static struct dentry *show_all_errors_dent  __read_mostly;
  88 static struct dentry *show_num_errors_dent  __read_mostly;
  89 static struct dentry *num_free_entries_dent __read_mostly;
  90 static struct dentry *min_free_entries_dent __read_mostly;
  91
  92 static const char *type2name[4] = { "single", "page",
  93                                     "scather-gather", "coherent" };
  94
  95 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
  96                                    "DMA_FROM_DEVICE", "DMA_NONE" };
  97
  98 /*
  99  * The access to some variables in this macro is racy. We can't use atomic_t
 100  * here because all these variables are exported to debugfs. Some of them even
 101  * writeable. This is also the reason why a lock won't help much. But anyway,
 102  * the races are no big deal. Here is why:
 103  *
 104  *   error_count: the addition is racy, but the worst thing that can happen is
 105  *                that we don't count some errors
 106  *   show_num_errors: the subtraction is racy. Also no big deal because in
 107  *                    worst case this will result in one warning more in the
 108  *                    system log than the user configured. This variable is
 109  *                    writeable via debugfs.
 110  */
 111 #define err_printk(dev, format, arg...) do {                    \
 112                 error_count += 1;                               \
 113                 if (show_all_errors || show_num_errors > 0) {   \
 114                         WARN(1, "%s %s: " format,               \
 115                              dev_driver_string(dev),            \
 116                              dev_name(dev) , ## arg);           \
 117                 }                                               \
 118                 if (!show_all_errors && show_num_errors > 0)    \
 119                         show_num_errors -= 1;                   \
 120         } while (0);
 121
 122 /*
 123  * Hash related functions
 124  *
 125  * Every DMA-API request is saved into a struct dma_debug_entry. To
 126  * have quick access to these structs they are stored into a hash.
 127  */
 128 static int hash_fn(struct dma_debug_entry *entry)
 129 {
 130         /*
 131          * Hash function is based on the dma address.
 132          * We use bits 20-27 here as the index into the hash
 133          */
 134         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 135 }
 136
 137 /*
 138  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 139  */
 140 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 141                                            unsigned long *flags)
 142 {
 143         int idx = hash_fn(entry);
 144         unsigned long __flags;
 145
 146         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 147         *flags = __flags;
 148         return &dma_entry_hash[idx];
 149 }
 150
 151 /*
 152  * Give up exclusive access to the hash bucket
 153  */
 154 static void put_hash_bucket(struct hash_bucket *bucket,
 155                             unsigned long *flags)
 156 {
 157         unsigned long __flags = *flags;
 158
 159         spin_unlock_irqrestore(&bucket->lock, __flags);
 160 }
 161
 162 /*
 163  * Search a given entry in the hash bucket list
 164  */
 165 static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
 166                                                 struct dma_debug_entry *ref)
 167 {
 168         struct dma_debug_entry *entry;
 169
 170         list_for_each_entry(entry, &bucket->list, list) {
 171                 if ((entry->dev_addr == ref->dev_addr) &&
 172                     (entry->dev == ref->dev))
 173                         return entry;
 174         }
 175
 176         return NULL;
 177 }
 178
 179 /*
 180  * Add an entry to a hash bucket
 181  */
 182 static void hash_bucket_add(struct hash_bucket *bucket,
 183                             struct dma_debug_entry *entry)
 184 {
 185         list_add_tail(&entry->list, &bucket->list);
 186 }
 187
 188 /*
 189  * Remove entry from a hash bucket list
 190  */
 191 static void hash_bucket_del(struct dma_debug_entry *entry)
 192 {
 193         list_del(&entry->list);
 194 }
 195
 196 /*
 197  * Dump mapping entries for debugging purposes
 198  */
 199 void debug_dma_dump_mappings(struct device *dev)
 200 {
 201         int idx;
 202
 203         for (idx = 0; idx < HASH_SIZE; idx++) {
 204                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 205                 struct dma_debug_entry *entry;
 206                 unsigned long flags;
 207
 208                 spin_lock_irqsave(&bucket->lock, flags);
 209
 210                 list_for_each_entry(entry, &bucket->list, list) {
 211                         if (!dev || dev == entry->dev) {
 212                                 dev_info(entry->dev,
 213                                          "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
 214                                          type2name[entry->type], idx,
 215                                          (unsigned long long)entry->paddr,
 216                                          entry->dev_addr, entry->size,
 217                                          dir2name[entry->direction]);
 218                         }
 219                 }
 220
 221                 spin_unlock_irqrestore(&bucket->lock, flags);
 222         }
 223 }
 224 EXPORT_SYMBOL(debug_dma_dump_mappings);
 225
 226 /*
 227  * Wrapper function for adding an entry to the hash.
 228  * This function takes care of locking itself.
 229  */
 230 static void add_dma_entry(struct dma_debug_entry *entry)
 231 {
 232         struct hash_bucket *bucket;
 233         unsigned long flags;
 234
 235         bucket = get_hash_bucket(entry, &flags);
 236         hash_bucket_add(bucket, entry);
 237         put_hash_bucket(bucket, &flags);
 238 }
 239
 240 /* struct dma_entry allocator
 241  *
 242  * The next two functions implement the allocator for
 243  * struct dma_debug_entries.
 244  */
 245 static struct dma_debug_entry *dma_entry_alloc(void)
 246 {
 247         struct dma_debug_entry *entry = NULL;
 248         unsigned long flags;
 249
 250         spin_lock_irqsave(&free_entries_lock, flags);
 251
 252         if (list_empty(&free_entries)) {
 253                 printk(KERN_ERR "DMA-API: debugging out of memory "
 254                                 "- disabling\n");
 255                 global_disable = true;
 256                 goto out;
 257         }
 258
 259         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 260         list_del(&entry->list);
 261         memset(entry, 0, sizeof(*entry));
 262
 263         num_free_entries -= 1;
 264         if (num_free_entries < min_free_entries)
 265                 min_free_entries = num_free_entries;
 266
 267 out:
 268         spin_unlock_irqrestore(&free_entries_lock, flags);
 269
 270         return entry;
 271 }
 272
 273 static void dma_entry_free(struct dma_debug_entry *entry)
 274 {
 275         unsigned long flags;
 276
 277         /*
 278          * add to beginning of the list - this way the entries are
 279          * more likely cache hot when they are reallocated.
 280          */
 281         spin_lock_irqsave(&free_entries_lock, flags);
 282         list_add(&entry->list, &free_entries);
 283         num_free_entries += 1;
 284         spin_unlock_irqrestore(&free_entries_lock, flags);
 285 }
 286
 287 /*
 288  * DMA-API debugging init code
 289  *
 290  * The init code does two things:
 291  *   1. Initialize core data structures
 292  *   2. Preallocate a given number of dma_debug_entry structs
 293  */
 294
 295 static int prealloc_memory(u32 num_entries)
 296 {
 297         struct dma_debug_entry *entry, *next_entry;
 298         int i;
 299
 300         for (i = 0; i < num_entries; ++i) {
 301                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 302                 if (!entry)
 303                         goto out_err;
 304
 305                 list_add_tail(&entry->list, &free_entries);
 306         }
 307
 308         num_free_entries = num_entries;
 309         min_free_entries = num_entries;
 310
 311         printk(KERN_INFO "DMA-API: preallocated %d debug entries\n",
 312                         num_entries);
 313
 314         return 0;
 315
 316 out_err:
 317
 318         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 319                 list_del(&entry->list);
 320                 kfree(entry);
 321         }
 322
 323         return -ENOMEM;
 324 }
 325
 326 static int dma_debug_fs_init(void)
 327 {
 328         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 329         if (!dma_debug_dent) {
 330                 printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
 331                 return -ENOMEM;
 332         }
 333
 334         global_disable_dent = debugfs_create_bool("disabled", 0444,
 335                         dma_debug_dent,
 336                         (u32 *)&global_disable);
 337         if (!global_disable_dent)
 338                 goto out_err;
 339
 340         error_count_dent = debugfs_create_u32("error_count", 0444,
 341                         dma_debug_dent, &error_count);
 342         if (!error_count_dent)
 343                 goto out_err;
 344
 345         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 346                         dma_debug_dent,
 347                         &show_all_errors);
 348         if (!show_all_errors_dent)
 349                 goto out_err;
 350
 351         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 352                         dma_debug_dent,
 353                         &show_num_errors);
 354         if (!show_num_errors_dent)
 355                 goto out_err;
 356
 357         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 358                         dma_debug_dent,
 359                         &num_free_entries);
 360         if (!num_free_entries_dent)
 361                 goto out_err;
 362
 363         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 364                         dma_debug_dent,
 365                         &min_free_entries);
 366         if (!min_free_entries_dent)
 367                 goto out_err;
 368
 369         return 0;
 370
 371 out_err:
 372         debugfs_remove_recursive(dma_debug_dent);
 373
 374         return -ENOMEM;
 375 }
 376
 377
 378 /*
 379  * Let the architectures decide how many entries should be preallocated.
 380  */
 381 void dma_debug_init(u32 num_entries)
 382 {
 383         int i;
 384
 385         if (global_disable)
 386                 return;
 387
 388         for (i = 0; i < HASH_SIZE; ++i) {
 389                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 390                 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
 391         }
 392
 393         if (dma_debug_fs_init() != 0) {
 394                 printk(KERN_ERR "DMA-API: error creating debugfs entries "
 395                                 "- disabling\n");
 396                 global_disable = true;
 397
 398                 return;
 399         }
 400
 401         if (req_entries)
 402                 num_entries = req_entries;
 403
 404         if (prealloc_memory(num_entries) != 0) {
 405                 printk(KERN_ERR "DMA-API: debugging out of memory error "
 406                                 "- disabled\n");
 407                 global_disable = true;
 408
 409                 return;
 410         }
 411
 412         printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
 413 }
 414
 415 static __init int dma_debug_cmdline(char *str)
 416 {
 417         if (!str)
 418                 return -EINVAL;
 419
 420         if (strncmp(str, "off", 3) == 0) {
 421                 printk(KERN_INFO "DMA-API: debugging disabled on kernel "
 422                                  "command line\n");
 423                 global_disable = true;
 424         }
 425
 426         return 0;
 427 }
 428
 429 static __init int dma_debug_entries_cmdline(char *str)
 430 {
 431         int res;
 432
 433         if (!str)
 434                 return -EINVAL;
 435
 436         res = get_option(&str, &req_entries);
 437
 438         if (!res)
 439                 req_entries = 0;
 440
 441         return 0;
 442 }
 443
 444 __setup("dma_debug=", dma_debug_cmdline);
 445 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
 446
 447 static void check_unmap(struct dma_debug_entry *ref)
 448 {
 449         struct dma_debug_entry *entry;
 450         struct hash_bucket *bucket;
 451         unsigned long flags;
 452
 453         if (dma_mapping_error(ref->dev, ref->dev_addr))
 454                 return;
 455
 456         bucket = get_hash_bucket(ref, &flags);
 457         entry = hash_bucket_find(bucket, ref);
 458
 459         if (!entry) {
 460                 err_printk(ref->dev, "DMA-API: device driver tries "
 461                            "to free DMA memory it has not allocated "
 462                            "[device address=0x%016llx] [size=%llu bytes]\n",
 463                            ref->dev_addr, ref->size);
 464                 goto out;
 465         }
 466
 467         if (ref->size != entry->size) {
 468                 err_printk(ref->dev, "DMA-API: device driver frees "
 469                            "DMA memory with different size "
 470                            "[device address=0x%016llx] [map size=%llu bytes] "
 471                            "[unmap size=%llu bytes]\n",
 472                            ref->dev_addr, entry->size, ref->size);
 473         }
 474
 475         if (ref->type != entry->type) {
 476                 err_printk(ref->dev, "DMA-API: device driver frees "
 477                            "DMA memory with wrong function "
 478                            "[device address=0x%016llx] [size=%llu bytes] "
 479                            "[mapped as %s] [unmapped as %s]\n",
 480                            ref->dev_addr, ref->size,
 481                            type2name[entry->type], type2name[ref->type]);
 482         } else if ((entry->type == dma_debug_coherent) &&
 483                    (ref->paddr != entry->paddr)) {
 484                 err_printk(ref->dev, "DMA-API: device driver frees "
 485                            "DMA memory with different CPU address "
 486                            "[device address=0x%016llx] [size=%llu bytes] "
 487                            "[cpu alloc address=%p] [cpu free address=%p]",
 488                            ref->dev_addr, ref->size,
 489                            (void *)entry->paddr, (void *)ref->paddr);
 490         }
 491
 492         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
 493             ref->sg_call_ents != entry->sg_call_ents) {
 494                 err_printk(ref->dev, "DMA-API: device driver frees "
 495                            "DMA sg list with different entry count "
 496                            "[map count=%d] [unmap count=%d]\n",
 497                            entry->sg_call_ents, ref->sg_call_ents);
 498         }
 499
 500         /*
 501          * This may be no bug in reality - but most implementations of the
 502          * DMA API don't handle this properly, so check for it here
 503          */
 504         if (ref->direction != entry->direction) {
 505                 err_printk(ref->dev, "DMA-API: device driver frees "
 506                            "DMA memory with different direction "
 507                            "[device address=0x%016llx] [size=%llu bytes] "
 508                            "[mapped with %s] [unmapped with %s]\n",
 509                            ref->dev_addr, ref->size,
 510                            dir2name[entry->direction],
 511                            dir2name[ref->direction]);
 512         }
 513
 514         hash_bucket_del(entry);
 515         dma_entry_free(entry);
 516
 517 out:
 518         put_hash_bucket(bucket, &flags);
 519 }
 520
 521 static void check_for_stack(struct device *dev, void *addr)
 522 {
 523         if (object_is_on_stack(addr))
 524                 err_printk(dev, "DMA-API: device driver maps memory from stack"
 525                                 " [addr=%p]\n", addr);
 526 }
 527
 528 static void check_sync(struct device *dev, dma_addr_t addr,
 529                        u64 size, u64 offset, int direction, bool to_cpu)
 530 {
 531         struct dma_debug_entry ref = {
 532                 .dev            = dev,
 533                 .dev_addr       = addr,
 534                 .size           = size,
 535                 .direction      = direction,
 536         };
 537         struct dma_debug_entry *entry;
 538         struct hash_bucket *bucket;
 539         unsigned long flags;
 540
 541         bucket = get_hash_bucket(&ref, &flags);
 542
 543         entry = hash_bucket_find(bucket, &ref);
 544
 545         if (!entry) {
 546                 err_printk(dev, "DMA-API: device driver tries "
 547                                 "to sync DMA memory it has not allocated "
 548                                 "[device address=0x%016llx] [size=%llu bytes]\n",
 549                                 addr, size);
 550                 goto out;
 551         }
 552
 553         if ((offset + size) > entry->size) {
 554                 err_printk(dev, "DMA-API: device driver syncs"
 555                                 " DMA memory outside allocated range "
 556                                 "[device address=0x%016llx] "
 557                                 "[allocation size=%llu bytes] [sync offset=%llu] "
 558                                 "[sync size=%llu]\n", entry->dev_addr, entry->size,
 559                                 offset, size);
 560         }
 561
 562         if (direction != entry->direction) {
 563                 err_printk(dev, "DMA-API: device driver syncs "
 564                                 "DMA memory with different direction "
 565                                 "[device address=0x%016llx] [size=%llu bytes] "
 566                                 "[mapped with %s] [synced with %s]\n",
 567                                 addr, entry->size,
 568                                 dir2name[entry->direction],
 569                                 dir2name[direction]);
 570         }
 571
 572         if (entry->direction == DMA_BIDIRECTIONAL)
 573                 goto out;
 574
 575         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
 576                       !(direction == DMA_TO_DEVICE))
 577                 err_printk(dev, "DMA-API: device driver syncs "
 578                                 "device read-only DMA memory for cpu "
 579                                 "[device address=0x%016llx] [size=%llu bytes] "
 580                                 "[mapped with %s] [synced with %s]\n",
 581                                 addr, entry->size,
 582                                 dir2name[entry->direction],
 583                                 dir2name[direction]);
 584
 585         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
 586                        !(direction == DMA_FROM_DEVICE))
 587                 err_printk(dev, "DMA-API: device driver syncs "
 588                                 "device write-only DMA memory to device "
 589                                 "[device address=0x%016llx] [size=%llu bytes] "
 590                                 "[mapped with %s] [synced with %s]\n",
 591                                 addr, entry->size,
 592                                 dir2name[entry->direction],
 593                                 dir2name[direction]);
 594
 595 out:
 596         put_hash_bucket(bucket, &flags);
 597
 598 }
 599
 600 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
 601                         size_t size, int direction, dma_addr_t dma_addr,
 602                         bool map_single)
 603 {
 604         struct dma_debug_entry *entry;
 605
 606         if (unlikely(global_disable))
 607                 return;
 608
 609         if (unlikely(dma_mapping_error(dev, dma_addr)))
 610                 return;
 611
 612         entry = dma_entry_alloc();
 613         if (!entry)
 614                 return;
 615
 616         entry->dev       = dev;
 617         entry->type      = dma_debug_page;
 618         entry->paddr     = page_to_phys(page) + offset;
 619         entry->dev_addr  = dma_addr;
 620         entry->size      = size;
 621         entry->direction = direction;
 622
 623         if (map_single) {
 624                 entry->type = dma_debug_single;
 625                 check_for_stack(dev, page_address(page) + offset);
 626         }
 627
 628         add_dma_entry(entry);
 629 }
 630 EXPORT_SYMBOL(debug_dma_map_page);
 631
 632 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
 633                           size_t size, int direction, bool map_single)
 634 {
 635         struct dma_debug_entry ref = {
 636                 .type           = dma_debug_page,
 637                 .dev            = dev,
 638                 .dev_addr       = addr,
 639                 .size           = size,
 640                 .direction      = direction,
 641         };
 642
 643         if (unlikely(global_disable))
 644                 return;
 645
 646         if (map_single)
 647                 ref.type = dma_debug_single;
 648
 649         check_unmap(&ref);
 650 }
 651 EXPORT_SYMBOL(debug_dma_unmap_page);
 652
 653 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
 654                       int nents, int mapped_ents, int direction)
 655 {
 656         struct dma_debug_entry *entry;
 657         struct scatterlist *s;
 658         int i;
 659
 660         if (unlikely(global_disable))
 661                 return;
 662
 663         for_each_sg(sg, s, mapped_ents, i) {
 664                 entry = dma_entry_alloc();
 665                 if (!entry)
 666                         return;
 667
 668                 entry->type           = dma_debug_sg;
 669                 entry->dev            = dev;
 670                 entry->paddr          = sg_phys(s);
 671                 entry->size           = s->length;
 672                 entry->dev_addr       = s->dma_address;
 673                 entry->direction      = direction;
 674                 entry->sg_call_ents   = nents;
 675                 entry->sg_mapped_ents = mapped_ents;
 676
 677                 check_for_stack(dev, sg_virt(s));
 678
 679                 add_dma_entry(entry);
 680         }
 681 }
 682 EXPORT_SYMBOL(debug_dma_map_sg);
 683
 684 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
 685                         int nelems, int dir)
 686 {
 687         struct dma_debug_entry *entry;
 688         struct scatterlist *s;
 689         int mapped_ents = 0, i;
 690         unsigned long flags;
 691
 692         if (unlikely(global_disable))
 693                 return;
 694
 695         for_each_sg(sglist, s, nelems, i) {
 696
 697                 struct dma_debug_entry ref = {
 698                         .type           = dma_debug_sg,
 699                         .dev            = dev,
 700                         .paddr          = sg_phys(s),
 701                         .dev_addr       = s->dma_address,
 702                         .size           = s->length,
 703                         .direction      = dir,
 704                         .sg_call_ents   = 0,
 705                 };
 706
 707                 if (mapped_ents && i >= mapped_ents)
 708                         break;
 709
 710                 if (mapped_ents == 0) {
 711                         struct hash_bucket *bucket;
 712                         ref.sg_call_ents = nelems;
 713                         bucket = get_hash_bucket(&ref, &flags);
 714                         entry = hash_bucket_find(bucket, &ref);
 715                         if (entry)
 716                                 mapped_ents = entry->sg_mapped_ents;
 717                         put_hash_bucket(bucket, &flags);
 718                 }
 719
 720                 check_unmap(&ref);
 721         }
 722 }
 723 EXPORT_SYMBOL(debug_dma_unmap_sg);
 724
 725 void debug_dma_alloc_coherent(struct device *dev, size_t size,
 726                               dma_addr_t dma_addr, void *virt)
 727 {
 728         struct dma_debug_entry *entry;
 729
 730         if (unlikely(global_disable))
 731                 return;
 732
 733         if (unlikely(virt == NULL))
 734                 return;
 735
 736         entry = dma_entry_alloc();
 737         if (!entry)
 738                 return;
 739
 740         entry->type      = dma_debug_coherent;
 741         entry->dev       = dev;
 742         entry->paddr     = virt_to_phys(virt);
 743         entry->size      = size;
 744         entry->dev_addr  = dma_addr;
 745         entry->direction = DMA_BIDIRECTIONAL;
 746
 747         add_dma_entry(entry);
 748 }
 749 EXPORT_SYMBOL(debug_dma_alloc_coherent);
 750
 751 void debug_dma_free_coherent(struct device *dev, size_t size,
 752                          void *virt, dma_addr_t addr)
 753 {
 754         struct dma_debug_entry ref = {
 755                 .type           = dma_debug_coherent,
 756                 .dev            = dev,
 757                 .paddr          = virt_to_phys(virt),
 758                 .dev_addr       = addr,
 759                 .size           = size,
 760                 .direction      = DMA_BIDIRECTIONAL,
 761         };
 762
 763         if (unlikely(global_disable))
 764                 return;
 765
 766         check_unmap(&ref);
 767 }
 768 EXPORT_SYMBOL(debug_dma_free_coherent);
 769
 770 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
 771                                    size_t size, int direction)
 772 {
 773         if (unlikely(global_disable))
 774                 return;
 775
 776         check_sync(dev, dma_handle, size, 0, direction, true);
 777 }
 778 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
 779
 780 void debug_dma_sync_single_for_device(struct device *dev,
 781                                       dma_addr_t dma_handle, size_t size,
 782                                       int direction)
 783 {
 784         if (unlikely(global_disable))
 785                 return;
 786
 787         check_sync(dev, dma_handle, size, 0, direction, false);
 788 }
 789 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
 790
 791 void debug_dma_sync_single_range_for_cpu(struct device *dev,
 792                                          dma_addr_t dma_handle,
 793                                          unsigned long offset, size_t size,
 794                                          int direction)
 795 {
 796         if (unlikely(global_disable))
 797                 return;
 798
 799         check_sync(dev, dma_handle, size, offset, direction, true);
 800 }
 801 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
 802
 803 void debug_dma_sync_single_range_for_device(struct device *dev,
 804                                             dma_addr_t dma_handle,
 805                                             unsigned long offset,
 806                                             size_t size, int direction)
 807 {
 808         if (unlikely(global_disable))
 809                 return;
 810
 811         check_sync(dev, dma_handle, size, offset, direction, false);
 812 }
 813 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
 814
 815 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 816                                int nelems, int direction)
 817 {
 818         struct scatterlist *s;
 819         int i;
 820
 821         if (unlikely(global_disable))
 822                 return;
 823
 824         for_each_sg(sg, s, nelems, i) {
 825                 check_sync(dev, s->dma_address, s->dma_length, 0,
 826                                 direction, true);
 827         }
 828 }
 829 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
 830
 831 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 832                                   int nelems, int direction)
 833 {
 834         struct scatterlist *s;
 835         int i;
 836
 837         if (unlikely(global_disable))
 838                 return;
 839
 840         for_each_sg(sg, s, nelems, i) {
 841                 check_sync(dev, s->dma_address, s->dma_length, 0,
 842                                 direction, false);
 843         }
 844 }
 845 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
 846