Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[pandora-kernel.git] / lib / dma-debug.c
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/stacktrace.h>
23 #include <linux/dma-debug.h>
24 #include <linux/spinlock.h>
25 #include <linux/debugfs.h>
26 #include <linux/uaccess.h>
27 #include <linux/export.h>
28 #include <linux/device.h>
29 #include <linux/types.h>
30 #include <linux/sched.h>
31 #include <linux/ctype.h>
32 #include <linux/list.h>
33 #include <linux/slab.h>
34
35 #include <asm/sections.h>
36
37 #define HASH_SIZE       1024ULL
38 #define HASH_FN_SHIFT   13
39 #define HASH_FN_MASK    (HASH_SIZE - 1)
40
41 enum {
42         dma_debug_single,
43         dma_debug_page,
44         dma_debug_sg,
45         dma_debug_coherent,
46 };
47
48 enum map_err_types {
49         MAP_ERR_CHECK_NOT_APPLICABLE,
50         MAP_ERR_NOT_CHECKED,
51         MAP_ERR_CHECKED,
52 };
53
54 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
55
56 /**
57  * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
58  * @list: node on pre-allocated free_entries list
59  * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
60  * @type: single, page, sg, coherent
61  * @pfn: page frame of the start address
62  * @offset: offset of mapping relative to pfn
63  * @size: length of the mapping
64  * @direction: enum dma_data_direction
65  * @sg_call_ents: 'nents' from dma_map_sg
66  * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
67  * @map_err_type: track whether dma_mapping_error() was checked
68  * @stacktrace: support backtraces when a violation is detected
69  */
70 struct dma_debug_entry {
71         struct list_head list;
72         struct device    *dev;
73         int              type;
74         unsigned long    pfn;
75         size_t           offset;
76         u64              dev_addr;
77         u64              size;
78         int              direction;
79         int              sg_call_ents;
80         int              sg_mapped_ents;
81         enum map_err_types  map_err_type;
82 #ifdef CONFIG_STACKTRACE
83         struct           stack_trace stacktrace;
84         unsigned long    st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
85 #endif
86 };
87
88 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
89
90 struct hash_bucket {
91         struct list_head list;
92         spinlock_t lock;
93 } ____cacheline_aligned_in_smp;
94
95 /* Hash list to save the allocated dma addresses */
96 static struct hash_bucket dma_entry_hash[HASH_SIZE];
97 /* List of pre-allocated dma_debug_entry's */
98 static LIST_HEAD(free_entries);
99 /* Lock for the list above */
100 static DEFINE_SPINLOCK(free_entries_lock);
101
102 /* Global disable flag - will be set in case of an error */
103 static u32 global_disable __read_mostly;
104
105 /* Early initialization disable flag, set at the end of dma_debug_init */
106 static bool dma_debug_initialized __read_mostly;
107
108 static inline bool dma_debug_disabled(void)
109 {
110         return global_disable || !dma_debug_initialized;
111 }
112
113 /* Global error count */
114 static u32 error_count;
115
116 /* Global error show enable*/
117 static u32 show_all_errors __read_mostly;
118 /* Number of errors to show */
119 static u32 show_num_errors = 1;
120
121 static u32 num_free_entries;
122 static u32 min_free_entries;
123 static u32 nr_total_entries;
124
125 /* number of preallocated entries requested by kernel cmdline */
126 static u32 req_entries;
127
128 /* debugfs dentry's for the stuff above */
129 static struct dentry *dma_debug_dent        __read_mostly;
130 static struct dentry *global_disable_dent   __read_mostly;
131 static struct dentry *error_count_dent      __read_mostly;
132 static struct dentry *show_all_errors_dent  __read_mostly;
133 static struct dentry *show_num_errors_dent  __read_mostly;
134 static struct dentry *num_free_entries_dent __read_mostly;
135 static struct dentry *min_free_entries_dent __read_mostly;
136 static struct dentry *filter_dent           __read_mostly;
137
138 /* per-driver filter related state */
139
140 #define NAME_MAX_LEN    64
141
142 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
143 static struct device_driver *current_driver                    __read_mostly;
144
145 static DEFINE_RWLOCK(driver_name_lock);
146
147 static const char *const maperr2str[] = {
148         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
149         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
150         [MAP_ERR_CHECKED] = "dma map error checked",
151 };
152
153 static const char *type2name[4] = { "single", "page",
154                                     "scather-gather", "coherent" };
155
156 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
157                                    "DMA_FROM_DEVICE", "DMA_NONE" };
158
159 /*
160  * The access to some variables in this macro is racy. We can't use atomic_t
161  * here because all these variables are exported to debugfs. Some of them even
162  * writeable. This is also the reason why a lock won't help much. But anyway,
163  * the races are no big deal. Here is why:
164  *
165  *   error_count: the addition is racy, but the worst thing that can happen is
166  *                that we don't count some errors
167  *   show_num_errors: the subtraction is racy. Also no big deal because in
168  *                    worst case this will result in one warning more in the
169  *                    system log than the user configured. This variable is
170  *                    writeable via debugfs.
171  */
172 static inline void dump_entry_trace(struct dma_debug_entry *entry)
173 {
174 #ifdef CONFIG_STACKTRACE
175         if (entry) {
176                 pr_warning("Mapped at:\n");
177                 print_stack_trace(&entry->stacktrace, 0);
178         }
179 #endif
180 }
181
182 static bool driver_filter(struct device *dev)
183 {
184         struct device_driver *drv;
185         unsigned long flags;
186         bool ret;
187
188         /* driver filter off */
189         if (likely(!current_driver_name[0]))
190                 return true;
191
192         /* driver filter on and initialized */
193         if (current_driver && dev && dev->driver == current_driver)
194                 return true;
195
196         /* driver filter on, but we can't filter on a NULL device... */
197         if (!dev)
198                 return false;
199
200         if (current_driver || !current_driver_name[0])
201                 return false;
202
203         /* driver filter on but not yet initialized */
204         drv = dev->driver;
205         if (!drv)
206                 return false;
207
208         /* lock to protect against change of current_driver_name */
209         read_lock_irqsave(&driver_name_lock, flags);
210
211         ret = false;
212         if (drv->name &&
213             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
214                 current_driver = drv;
215                 ret = true;
216         }
217
218         read_unlock_irqrestore(&driver_name_lock, flags);
219
220         return ret;
221 }
222
223 #define err_printk(dev, entry, format, arg...) do {                     \
224                 error_count += 1;                                       \
225                 if (driver_filter(dev) &&                               \
226                     (show_all_errors || show_num_errors > 0)) {         \
227                         WARN(1, "%s %s: " format,                       \
228                              dev ? dev_driver_string(dev) : "NULL",     \
229                              dev ? dev_name(dev) : "NULL", ## arg);     \
230                         dump_entry_trace(entry);                        \
231                 }                                                       \
232                 if (!show_all_errors && show_num_errors > 0)            \
233                         show_num_errors -= 1;                           \
234         } while (0);
235
236 /*
237  * Hash related functions
238  *
239  * Every DMA-API request is saved into a struct dma_debug_entry. To
240  * have quick access to these structs they are stored into a hash.
241  */
242 static int hash_fn(struct dma_debug_entry *entry)
243 {
244         /*
245          * Hash function is based on the dma address.
246          * We use bits 20-27 here as the index into the hash
247          */
248         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
249 }
250
251 /*
252  * Request exclusive access to a hash bucket for a given dma_debug_entry.
253  */
254 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
255                                            unsigned long *flags)
256 {
257         int idx = hash_fn(entry);
258         unsigned long __flags;
259
260         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
261         *flags = __flags;
262         return &dma_entry_hash[idx];
263 }
264
265 /*
266  * Give up exclusive access to the hash bucket
267  */
268 static void put_hash_bucket(struct hash_bucket *bucket,
269                             unsigned long *flags)
270 {
271         unsigned long __flags = *flags;
272
273         spin_unlock_irqrestore(&bucket->lock, __flags);
274 }
275
276 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
277 {
278         return ((a->dev_addr == b->dev_addr) &&
279                 (a->dev == b->dev)) ? true : false;
280 }
281
282 static bool containing_match(struct dma_debug_entry *a,
283                              struct dma_debug_entry *b)
284 {
285         if (a->dev != b->dev)
286                 return false;
287
288         if ((b->dev_addr <= a->dev_addr) &&
289             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
290                 return true;
291
292         return false;
293 }
294
295 /*
296  * Search a given entry in the hash bucket list
297  */
298 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
299                                                   struct dma_debug_entry *ref,
300                                                   match_fn match)
301 {
302         struct dma_debug_entry *entry, *ret = NULL;
303         int matches = 0, match_lvl, last_lvl = -1;
304
305         list_for_each_entry(entry, &bucket->list, list) {
306                 if (!match(ref, entry))
307                         continue;
308
309                 /*
310                  * Some drivers map the same physical address multiple
311                  * times. Without a hardware IOMMU this results in the
312                  * same device addresses being put into the dma-debug
313                  * hash multiple times too. This can result in false
314                  * positives being reported. Therefore we implement a
315                  * best-fit algorithm here which returns the entry from
316                  * the hash which fits best to the reference value
317                  * instead of the first-fit.
318                  */
319                 matches += 1;
320                 match_lvl = 0;
321                 entry->size         == ref->size         ? ++match_lvl : 0;
322                 entry->type         == ref->type         ? ++match_lvl : 0;
323                 entry->direction    == ref->direction    ? ++match_lvl : 0;
324                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
325
326                 if (match_lvl == 4) {
327                         /* perfect-fit - return the result */
328                         return entry;
329                 } else if (match_lvl > last_lvl) {
330                         /*
331                          * We found an entry that fits better then the
332                          * previous one or it is the 1st match.
333                          */
334                         last_lvl = match_lvl;
335                         ret      = entry;
336                 }
337         }
338
339         /*
340          * If we have multiple matches but no perfect-fit, just return
341          * NULL.
342          */
343         ret = (matches == 1) ? ret : NULL;
344
345         return ret;
346 }
347
348 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
349                                                  struct dma_debug_entry *ref)
350 {
351         return __hash_bucket_find(bucket, ref, exact_match);
352 }
353
354 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
355                                                    struct dma_debug_entry *ref,
356                                                    unsigned long *flags)
357 {
358
359         unsigned int max_range = dma_get_max_seg_size(ref->dev);
360         struct dma_debug_entry *entry, index = *ref;
361         unsigned int range = 0;
362
363         while (range <= max_range) {
364                 entry = __hash_bucket_find(*bucket, &index, containing_match);
365
366                 if (entry)
367                         return entry;
368
369                 /*
370                  * Nothing found, go back a hash bucket
371                  */
372                 put_hash_bucket(*bucket, flags);
373                 range          += (1 << HASH_FN_SHIFT);
374                 index.dev_addr -= (1 << HASH_FN_SHIFT);
375                 *bucket = get_hash_bucket(&index, flags);
376         }
377
378         return NULL;
379 }
380
381 /*
382  * Add an entry to a hash bucket
383  */
384 static void hash_bucket_add(struct hash_bucket *bucket,
385                             struct dma_debug_entry *entry)
386 {
387         list_add_tail(&entry->list, &bucket->list);
388 }
389
390 /*
391  * Remove entry from a hash bucket list
392  */
393 static void hash_bucket_del(struct dma_debug_entry *entry)
394 {
395         list_del(&entry->list);
396 }
397
398 static unsigned long long phys_addr(struct dma_debug_entry *entry)
399 {
400         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
401 }
402
403 /*
404  * Dump mapping entries for debugging purposes
405  */
406 void debug_dma_dump_mappings(struct device *dev)
407 {
408         int idx;
409
410         for (idx = 0; idx < HASH_SIZE; idx++) {
411                 struct hash_bucket *bucket = &dma_entry_hash[idx];
412                 struct dma_debug_entry *entry;
413                 unsigned long flags;
414
415                 spin_lock_irqsave(&bucket->lock, flags);
416
417                 list_for_each_entry(entry, &bucket->list, list) {
418                         if (!dev || dev == entry->dev) {
419                                 dev_info(entry->dev,
420                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
421                                          type2name[entry->type], idx,
422                                          phys_addr(entry), entry->pfn,
423                                          entry->dev_addr, entry->size,
424                                          dir2name[entry->direction],
425                                          maperr2str[entry->map_err_type]);
426                         }
427                 }
428
429                 spin_unlock_irqrestore(&bucket->lock, flags);
430         }
431 }
432 EXPORT_SYMBOL(debug_dma_dump_mappings);
433
434 /*
435  * For each mapping (initial cacheline in the case of
436  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
437  * scatterlist, or the cacheline specified in dma_map_single) insert
438  * into this tree using the cacheline as the key. At
439  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
440  * the entry already exists at insertion time add a tag as a reference
441  * count for the overlapping mappings.  For now, the overlap tracking
442  * just ensures that 'unmaps' balance 'maps' before marking the
443  * cacheline idle, but we should also be flagging overlaps as an API
444  * violation.
445  *
446  * Memory usage is mostly constrained by the maximum number of available
447  * dma-debug entries in that we need a free dma_debug_entry before
448  * inserting into the tree.  In the case of dma_map_page and
449  * dma_alloc_coherent there is only one dma_debug_entry and one
450  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
451  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
452  * entries into the tree.
453  *
454  * At any time debug_dma_assert_idle() can be called to trigger a
455  * warning if any cachelines in the given page are in the active set.
456  */
457 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
458 static DEFINE_SPINLOCK(radix_lock);
459 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
460 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
461 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
462
463 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
464 {
465         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
466                 (entry->offset >> L1_CACHE_SHIFT);
467 }
468
469 static int active_cacheline_read_overlap(phys_addr_t cln)
470 {
471         int overlap = 0, i;
472
473         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
474                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
475                         overlap |= 1 << i;
476         return overlap;
477 }
478
479 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
480 {
481         int i;
482
483         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
484                 return overlap;
485
486         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
487                 if (overlap & 1 << i)
488                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
489                 else
490                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
491
492         return overlap;
493 }
494
495 static void active_cacheline_inc_overlap(phys_addr_t cln)
496 {
497         int overlap = active_cacheline_read_overlap(cln);
498
499         overlap = active_cacheline_set_overlap(cln, ++overlap);
500
501         /* If we overflowed the overlap counter then we're potentially
502          * leaking dma-mappings.  Otherwise, if maps and unmaps are
503          * balanced then this overflow may cause false negatives in
504          * debug_dma_assert_idle() as the cacheline may be marked idle
505          * prematurely.
506          */
507         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
508                   "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n",
509                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
510 }
511
512 static int active_cacheline_dec_overlap(phys_addr_t cln)
513 {
514         int overlap = active_cacheline_read_overlap(cln);
515
516         return active_cacheline_set_overlap(cln, --overlap);
517 }
518
519 static int active_cacheline_insert(struct dma_debug_entry *entry)
520 {
521         phys_addr_t cln = to_cacheline_number(entry);
522         unsigned long flags;
523         int rc;
524
525         /* If the device is not writing memory then we don't have any
526          * concerns about the cpu consuming stale data.  This mitigates
527          * legitimate usages of overlapping mappings.
528          */
529         if (entry->direction == DMA_TO_DEVICE)
530                 return 0;
531
532         spin_lock_irqsave(&radix_lock, flags);
533         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
534         if (rc == -EEXIST)
535                 active_cacheline_inc_overlap(cln);
536         spin_unlock_irqrestore(&radix_lock, flags);
537
538         return rc;
539 }
540
541 static void active_cacheline_remove(struct dma_debug_entry *entry)
542 {
543         phys_addr_t cln = to_cacheline_number(entry);
544         unsigned long flags;
545
546         /* ...mirror the insert case */
547         if (entry->direction == DMA_TO_DEVICE)
548                 return;
549
550         spin_lock_irqsave(&radix_lock, flags);
551         /* since we are counting overlaps the final put of the
552          * cacheline will occur when the overlap count is 0.
553          * active_cacheline_dec_overlap() returns -1 in that case
554          */
555         if (active_cacheline_dec_overlap(cln) < 0)
556                 radix_tree_delete(&dma_active_cacheline, cln);
557         spin_unlock_irqrestore(&radix_lock, flags);
558 }
559
560 /**
561  * debug_dma_assert_idle() - assert that a page is not undergoing dma
562  * @page: page to lookup in the dma_active_cacheline tree
563  *
564  * Place a call to this routine in cases where the cpu touching the page
565  * before the dma completes (page is dma_unmapped) will lead to data
566  * corruption.
567  */
568 void debug_dma_assert_idle(struct page *page)
569 {
570         static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
571         struct dma_debug_entry *entry = NULL;
572         void **results = (void **) &ents;
573         unsigned int nents, i;
574         unsigned long flags;
575         phys_addr_t cln;
576
577         if (!page)
578                 return;
579
580         cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
581         spin_lock_irqsave(&radix_lock, flags);
582         nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
583                                        CACHELINES_PER_PAGE);
584         for (i = 0; i < nents; i++) {
585                 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
586
587                 if (ent_cln == cln) {
588                         entry = ents[i];
589                         break;
590                 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
591                         break;
592         }
593         spin_unlock_irqrestore(&radix_lock, flags);
594
595         if (!entry)
596                 return;
597
598         cln = to_cacheline_number(entry);
599         err_printk(entry->dev, entry,
600                    "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n",
601                    &cln);
602 }
603
604 /*
605  * Wrapper function for adding an entry to the hash.
606  * This function takes care of locking itself.
607  */
608 static void add_dma_entry(struct dma_debug_entry *entry)
609 {
610         struct hash_bucket *bucket;
611         unsigned long flags;
612         int rc;
613
614         bucket = get_hash_bucket(entry, &flags);
615         hash_bucket_add(bucket, entry);
616         put_hash_bucket(bucket, &flags);
617
618         rc = active_cacheline_insert(entry);
619         if (rc == -ENOMEM) {
620                 pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n");
621                 global_disable = true;
622         }
623
624         /* TODO: report -EEXIST errors here as overlapping mappings are
625          * not supported by the DMA API
626          */
627 }
628
629 static struct dma_debug_entry *__dma_entry_alloc(void)
630 {
631         struct dma_debug_entry *entry;
632
633         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
634         list_del(&entry->list);
635         memset(entry, 0, sizeof(*entry));
636
637         num_free_entries -= 1;
638         if (num_free_entries < min_free_entries)
639                 min_free_entries = num_free_entries;
640
641         return entry;
642 }
643
644 /* struct dma_entry allocator
645  *
646  * The next two functions implement the allocator for
647  * struct dma_debug_entries.
648  */
649 static struct dma_debug_entry *dma_entry_alloc(void)
650 {
651         struct dma_debug_entry *entry;
652         unsigned long flags;
653
654         spin_lock_irqsave(&free_entries_lock, flags);
655
656         if (list_empty(&free_entries)) {
657                 pr_err("DMA-API: debugging out of memory - disabling\n");
658                 global_disable = true;
659                 spin_unlock_irqrestore(&free_entries_lock, flags);
660                 return NULL;
661         }
662
663         entry = __dma_entry_alloc();
664
665         spin_unlock_irqrestore(&free_entries_lock, flags);
666
667 #ifdef CONFIG_STACKTRACE
668         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
669         entry->stacktrace.entries = entry->st_entries;
670         entry->stacktrace.skip = 2;
671         save_stack_trace(&entry->stacktrace);
672 #endif
673
674         return entry;
675 }
676
677 static void dma_entry_free(struct dma_debug_entry *entry)
678 {
679         unsigned long flags;
680
681         active_cacheline_remove(entry);
682
683         /*
684          * add to beginning of the list - this way the entries are
685          * more likely cache hot when they are reallocated.
686          */
687         spin_lock_irqsave(&free_entries_lock, flags);
688         list_add(&entry->list, &free_entries);
689         num_free_entries += 1;
690         spin_unlock_irqrestore(&free_entries_lock, flags);
691 }
692
693 int dma_debug_resize_entries(u32 num_entries)
694 {
695         int i, delta, ret = 0;
696         unsigned long flags;
697         struct dma_debug_entry *entry;
698         LIST_HEAD(tmp);
699
700         spin_lock_irqsave(&free_entries_lock, flags);
701
702         if (nr_total_entries < num_entries) {
703                 delta = num_entries - nr_total_entries;
704
705                 spin_unlock_irqrestore(&free_entries_lock, flags);
706
707                 for (i = 0; i < delta; i++) {
708                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
709                         if (!entry)
710                                 break;
711
712                         list_add_tail(&entry->list, &tmp);
713                 }
714
715                 spin_lock_irqsave(&free_entries_lock, flags);
716
717                 list_splice(&tmp, &free_entries);
718                 nr_total_entries += i;
719                 num_free_entries += i;
720         } else {
721                 delta = nr_total_entries - num_entries;
722
723                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
724                         entry = __dma_entry_alloc();
725                         kfree(entry);
726                 }
727
728                 nr_total_entries -= i;
729         }
730
731         if (nr_total_entries != num_entries)
732                 ret = 1;
733
734         spin_unlock_irqrestore(&free_entries_lock, flags);
735
736         return ret;
737 }
738 EXPORT_SYMBOL(dma_debug_resize_entries);
739
740 /*
741  * DMA-API debugging init code
742  *
743  * The init code does two things:
744  *   1. Initialize core data structures
745  *   2. Preallocate a given number of dma_debug_entry structs
746  */
747
748 static int prealloc_memory(u32 num_entries)
749 {
750         struct dma_debug_entry *entry, *next_entry;
751         int i;
752
753         for (i = 0; i < num_entries; ++i) {
754                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
755                 if (!entry)
756                         goto out_err;
757
758                 list_add_tail(&entry->list, &free_entries);
759         }
760
761         num_free_entries = num_entries;
762         min_free_entries = num_entries;
763
764         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
765
766         return 0;
767
768 out_err:
769
770         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
771                 list_del(&entry->list);
772                 kfree(entry);
773         }
774
775         return -ENOMEM;
776 }
777
778 static ssize_t filter_read(struct file *file, char __user *user_buf,
779                            size_t count, loff_t *ppos)
780 {
781         char buf[NAME_MAX_LEN + 1];
782         unsigned long flags;
783         int len;
784
785         if (!current_driver_name[0])
786                 return 0;
787
788         /*
789          * We can't copy to userspace directly because current_driver_name can
790          * only be read under the driver_name_lock with irqs disabled. So
791          * create a temporary copy first.
792          */
793         read_lock_irqsave(&driver_name_lock, flags);
794         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
795         read_unlock_irqrestore(&driver_name_lock, flags);
796
797         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
798 }
799
800 static ssize_t filter_write(struct file *file, const char __user *userbuf,
801                             size_t count, loff_t *ppos)
802 {
803         char buf[NAME_MAX_LEN];
804         unsigned long flags;
805         size_t len;
806         int i;
807
808         /*
809          * We can't copy from userspace directly. Access to
810          * current_driver_name is protected with a write_lock with irqs
811          * disabled. Since copy_from_user can fault and may sleep we
812          * need to copy to temporary buffer first
813          */
814         len = min(count, (size_t)(NAME_MAX_LEN - 1));
815         if (copy_from_user(buf, userbuf, len))
816                 return -EFAULT;
817
818         buf[len] = 0;
819
820         write_lock_irqsave(&driver_name_lock, flags);
821
822         /*
823          * Now handle the string we got from userspace very carefully.
824          * The rules are:
825          *         - only use the first token we got
826          *         - token delimiter is everything looking like a space
827          *           character (' ', '\n', '\t' ...)
828          *
829          */
830         if (!isalnum(buf[0])) {
831                 /*
832                  * If the first character userspace gave us is not
833                  * alphanumerical then assume the filter should be
834                  * switched off.
835                  */
836                 if (current_driver_name[0])
837                         pr_info("DMA-API: switching off dma-debug driver filter\n");
838                 current_driver_name[0] = 0;
839                 current_driver = NULL;
840                 goto out_unlock;
841         }
842
843         /*
844          * Now parse out the first token and use it as the name for the
845          * driver to filter for.
846          */
847         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
848                 current_driver_name[i] = buf[i];
849                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
850                         break;
851         }
852         current_driver_name[i] = 0;
853         current_driver = NULL;
854
855         pr_info("DMA-API: enable driver filter for driver [%s]\n",
856                 current_driver_name);
857
858 out_unlock:
859         write_unlock_irqrestore(&driver_name_lock, flags);
860
861         return count;
862 }
863
864 static const struct file_operations filter_fops = {
865         .read  = filter_read,
866         .write = filter_write,
867         .llseek = default_llseek,
868 };
869
870 static int dma_debug_fs_init(void)
871 {
872         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
873         if (!dma_debug_dent) {
874                 pr_err("DMA-API: can not create debugfs directory\n");
875                 return -ENOMEM;
876         }
877
878         global_disable_dent = debugfs_create_bool("disabled", 0444,
879                         dma_debug_dent,
880                         &global_disable);
881         if (!global_disable_dent)
882                 goto out_err;
883
884         error_count_dent = debugfs_create_u32("error_count", 0444,
885                         dma_debug_dent, &error_count);
886         if (!error_count_dent)
887                 goto out_err;
888
889         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
890                         dma_debug_dent,
891                         &show_all_errors);
892         if (!show_all_errors_dent)
893                 goto out_err;
894
895         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
896                         dma_debug_dent,
897                         &show_num_errors);
898         if (!show_num_errors_dent)
899                 goto out_err;
900
901         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
902                         dma_debug_dent,
903                         &num_free_entries);
904         if (!num_free_entries_dent)
905                 goto out_err;
906
907         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
908                         dma_debug_dent,
909                         &min_free_entries);
910         if (!min_free_entries_dent)
911                 goto out_err;
912
913         filter_dent = debugfs_create_file("driver_filter", 0644,
914                                           dma_debug_dent, NULL, &filter_fops);
915         if (!filter_dent)
916                 goto out_err;
917
918         return 0;
919
920 out_err:
921         debugfs_remove_recursive(dma_debug_dent);
922
923         return -ENOMEM;
924 }
925
926 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
927 {
928         struct dma_debug_entry *entry;
929         unsigned long flags;
930         int count = 0, i;
931
932         local_irq_save(flags);
933
934         for (i = 0; i < HASH_SIZE; ++i) {
935                 spin_lock(&dma_entry_hash[i].lock);
936                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
937                         if (entry->dev == dev) {
938                                 count += 1;
939                                 *out_entry = entry;
940                         }
941                 }
942                 spin_unlock(&dma_entry_hash[i].lock);
943         }
944
945         local_irq_restore(flags);
946
947         return count;
948 }
949
950 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
951 {
952         struct device *dev = data;
953         struct dma_debug_entry *uninitialized_var(entry);
954         int count;
955
956         if (dma_debug_disabled())
957                 return 0;
958
959         switch (action) {
960         case BUS_NOTIFY_UNBOUND_DRIVER:
961                 count = device_dma_allocations(dev, &entry);
962                 if (count == 0)
963                         break;
964                 err_printk(dev, entry, "DMA-API: device driver has pending "
965                                 "DMA allocations while released from device "
966                                 "[count=%d]\n"
967                                 "One of leaked entries details: "
968                                 "[device address=0x%016llx] [size=%llu bytes] "
969                                 "[mapped with %s] [mapped as %s]\n",
970                         count, entry->dev_addr, entry->size,
971                         dir2name[entry->direction], type2name[entry->type]);
972                 break;
973         default:
974                 break;
975         }
976
977         return 0;
978 }
979
980 void dma_debug_add_bus(struct bus_type *bus)
981 {
982         struct notifier_block *nb;
983
984         if (dma_debug_disabled())
985                 return;
986
987         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
988         if (nb == NULL) {
989                 pr_err("dma_debug_add_bus: out of memory\n");
990                 return;
991         }
992
993         nb->notifier_call = dma_debug_device_change;
994
995         bus_register_notifier(bus, nb);
996 }
997
998 /*
999  * Let the architectures decide how many entries should be preallocated.
1000  */
1001 void dma_debug_init(u32 num_entries)
1002 {
1003         int i;
1004
1005         /* Do not use dma_debug_initialized here, since we really want to be
1006          * called to set dma_debug_initialized
1007          */
1008         if (global_disable)
1009                 return;
1010
1011         for (i = 0; i < HASH_SIZE; ++i) {
1012                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
1013                 spin_lock_init(&dma_entry_hash[i].lock);
1014         }
1015
1016         if (dma_debug_fs_init() != 0) {
1017                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
1018                 global_disable = true;
1019
1020                 return;
1021         }
1022
1023         if (req_entries)
1024                 num_entries = req_entries;
1025
1026         if (prealloc_memory(num_entries) != 0) {
1027                 pr_err("DMA-API: debugging out of memory error - disabled\n");
1028                 global_disable = true;
1029
1030                 return;
1031         }
1032
1033         nr_total_entries = num_free_entries;
1034
1035         dma_debug_initialized = true;
1036
1037         pr_info("DMA-API: debugging enabled by kernel config\n");
1038 }
1039
1040 static __init int dma_debug_cmdline(char *str)
1041 {
1042         if (!str)
1043                 return -EINVAL;
1044
1045         if (strncmp(str, "off", 3) == 0) {
1046                 pr_info("DMA-API: debugging disabled on kernel command line\n");
1047                 global_disable = true;
1048         }
1049
1050         return 0;
1051 }
1052
1053 static __init int dma_debug_entries_cmdline(char *str)
1054 {
1055         int res;
1056
1057         if (!str)
1058                 return -EINVAL;
1059
1060         res = get_option(&str, &req_entries);
1061
1062         if (!res)
1063                 req_entries = 0;
1064
1065         return 0;
1066 }
1067
1068 __setup("dma_debug=", dma_debug_cmdline);
1069 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1070
1071 static void check_unmap(struct dma_debug_entry *ref)
1072 {
1073         struct dma_debug_entry *entry;
1074         struct hash_bucket *bucket;
1075         unsigned long flags;
1076
1077         bucket = get_hash_bucket(ref, &flags);
1078         entry = bucket_find_exact(bucket, ref);
1079
1080         if (!entry) {
1081                 /* must drop lock before calling dma_mapping_error */
1082                 put_hash_bucket(bucket, &flags);
1083
1084                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1085                         err_printk(ref->dev, NULL,
1086                                    "DMA-API: device driver tries to free an "
1087                                    "invalid DMA memory address\n");
1088                 } else {
1089                         err_printk(ref->dev, NULL,
1090                                    "DMA-API: device driver tries to free DMA "
1091                                    "memory it has not allocated [device "
1092                                    "address=0x%016llx] [size=%llu bytes]\n",
1093                                    ref->dev_addr, ref->size);
1094                 }
1095                 return;
1096         }
1097
1098         if (ref->size != entry->size) {
1099                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1100                            "DMA memory with different size "
1101                            "[device address=0x%016llx] [map size=%llu bytes] "
1102                            "[unmap size=%llu bytes]\n",
1103                            ref->dev_addr, entry->size, ref->size);
1104         }
1105
1106         if (ref->type != entry->type) {
1107                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1108                            "DMA memory with wrong function "
1109                            "[device address=0x%016llx] [size=%llu bytes] "
1110                            "[mapped as %s] [unmapped as %s]\n",
1111                            ref->dev_addr, ref->size,
1112                            type2name[entry->type], type2name[ref->type]);
1113         } else if ((entry->type == dma_debug_coherent) &&
1114                    (phys_addr(ref) != phys_addr(entry))) {
1115                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1116                            "DMA memory with different CPU address "
1117                            "[device address=0x%016llx] [size=%llu bytes] "
1118                            "[cpu alloc address=0x%016llx] "
1119                            "[cpu free address=0x%016llx]",
1120                            ref->dev_addr, ref->size,
1121                            phys_addr(entry),
1122                            phys_addr(ref));
1123         }
1124
1125         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1126             ref->sg_call_ents != entry->sg_call_ents) {
1127                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1128                            "DMA sg list with different entry count "
1129                            "[map count=%d] [unmap count=%d]\n",
1130                            entry->sg_call_ents, ref->sg_call_ents);
1131         }
1132
1133         /*
1134          * This may be no bug in reality - but most implementations of the
1135          * DMA API don't handle this properly, so check for it here
1136          */
1137         if (ref->direction != entry->direction) {
1138                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1139                            "DMA memory with different direction "
1140                            "[device address=0x%016llx] [size=%llu bytes] "
1141                            "[mapped with %s] [unmapped with %s]\n",
1142                            ref->dev_addr, ref->size,
1143                            dir2name[entry->direction],
1144                            dir2name[ref->direction]);
1145         }
1146
1147         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1148                 err_printk(ref->dev, entry,
1149                            "DMA-API: device driver failed to check map error"
1150                            "[device address=0x%016llx] [size=%llu bytes] "
1151                            "[mapped as %s]",
1152                            ref->dev_addr, ref->size,
1153                            type2name[entry->type]);
1154         }
1155
1156         hash_bucket_del(entry);
1157         dma_entry_free(entry);
1158
1159         put_hash_bucket(bucket, &flags);
1160 }
1161
1162 static void check_for_stack(struct device *dev, void *addr)
1163 {
1164         if (object_is_on_stack(addr))
1165                 err_printk(dev, NULL, "DMA-API: device driver maps memory from "
1166                                 "stack [addr=%p]\n", addr);
1167 }
1168
1169 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1170 {
1171         unsigned long a1 = (unsigned long)addr;
1172         unsigned long b1 = a1 + len;
1173         unsigned long a2 = (unsigned long)start;
1174         unsigned long b2 = (unsigned long)end;
1175
1176         return !(b1 <= a2 || a1 >= b2);
1177 }
1178
1179 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1180 {
1181         if (overlap(addr, len, _text, _etext) ||
1182             overlap(addr, len, __start_rodata, __end_rodata))
1183                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1184 }
1185
1186 static void check_sync(struct device *dev,
1187                        struct dma_debug_entry *ref,
1188                        bool to_cpu)
1189 {
1190         struct dma_debug_entry *entry;
1191         struct hash_bucket *bucket;
1192         unsigned long flags;
1193
1194         bucket = get_hash_bucket(ref, &flags);
1195
1196         entry = bucket_find_contain(&bucket, ref, &flags);
1197
1198         if (!entry) {
1199                 err_printk(dev, NULL, "DMA-API: device driver tries "
1200                                 "to sync DMA memory it has not allocated "
1201                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1202                                 (unsigned long long)ref->dev_addr, ref->size);
1203                 goto out;
1204         }
1205
1206         if (ref->size > entry->size) {
1207                 err_printk(dev, entry, "DMA-API: device driver syncs"
1208                                 " DMA memory outside allocated range "
1209                                 "[device address=0x%016llx] "
1210                                 "[allocation size=%llu bytes] "
1211                                 "[sync offset+size=%llu]\n",
1212                                 entry->dev_addr, entry->size,
1213                                 ref->size);
1214         }
1215
1216         if (entry->direction == DMA_BIDIRECTIONAL)
1217                 goto out;
1218
1219         if (ref->direction != entry->direction) {
1220                 err_printk(dev, entry, "DMA-API: device driver syncs "
1221                                 "DMA memory with different direction "
1222                                 "[device address=0x%016llx] [size=%llu bytes] "
1223                                 "[mapped with %s] [synced with %s]\n",
1224                                 (unsigned long long)ref->dev_addr, entry->size,
1225                                 dir2name[entry->direction],
1226                                 dir2name[ref->direction]);
1227         }
1228
1229         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1230                       !(ref->direction == DMA_TO_DEVICE))
1231                 err_printk(dev, entry, "DMA-API: device driver syncs "
1232                                 "device read-only DMA memory for cpu "
1233                                 "[device address=0x%016llx] [size=%llu bytes] "
1234                                 "[mapped with %s] [synced with %s]\n",
1235                                 (unsigned long long)ref->dev_addr, entry->size,
1236                                 dir2name[entry->direction],
1237                                 dir2name[ref->direction]);
1238
1239         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1240                        !(ref->direction == DMA_FROM_DEVICE))
1241                 err_printk(dev, entry, "DMA-API: device driver syncs "
1242                                 "device write-only DMA memory to device "
1243                                 "[device address=0x%016llx] [size=%llu bytes] "
1244                                 "[mapped with %s] [synced with %s]\n",
1245                                 (unsigned long long)ref->dev_addr, entry->size,
1246                                 dir2name[entry->direction],
1247                                 dir2name[ref->direction]);
1248
1249 out:
1250         put_hash_bucket(bucket, &flags);
1251 }
1252
1253 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1254                         size_t size, int direction, dma_addr_t dma_addr,
1255                         bool map_single)
1256 {
1257         struct dma_debug_entry *entry;
1258
1259         if (unlikely(dma_debug_disabled()))
1260                 return;
1261
1262         if (dma_mapping_error(dev, dma_addr))
1263                 return;
1264
1265         entry = dma_entry_alloc();
1266         if (!entry)
1267                 return;
1268
1269         entry->dev       = dev;
1270         entry->type      = dma_debug_page;
1271         entry->pfn       = page_to_pfn(page);
1272         entry->offset    = offset,
1273         entry->dev_addr  = dma_addr;
1274         entry->size      = size;
1275         entry->direction = direction;
1276         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1277
1278         if (map_single)
1279                 entry->type = dma_debug_single;
1280
1281         if (!PageHighMem(page)) {
1282                 void *addr = page_address(page) + offset;
1283
1284                 check_for_stack(dev, addr);
1285                 check_for_illegal_area(dev, addr, size);
1286         }
1287
1288         add_dma_entry(entry);
1289 }
1290 EXPORT_SYMBOL(debug_dma_map_page);
1291
1292 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1293 {
1294         struct dma_debug_entry ref;
1295         struct dma_debug_entry *entry;
1296         struct hash_bucket *bucket;
1297         unsigned long flags;
1298
1299         if (unlikely(dma_debug_disabled()))
1300                 return;
1301
1302         ref.dev = dev;
1303         ref.dev_addr = dma_addr;
1304         bucket = get_hash_bucket(&ref, &flags);
1305
1306         list_for_each_entry(entry, &bucket->list, list) {
1307                 if (!exact_match(&ref, entry))
1308                         continue;
1309
1310                 /*
1311                  * The same physical address can be mapped multiple
1312                  * times. Without a hardware IOMMU this results in the
1313                  * same device addresses being put into the dma-debug
1314                  * hash multiple times too. This can result in false
1315                  * positives being reported. Therefore we implement a
1316                  * best-fit algorithm here which updates the first entry
1317                  * from the hash which fits the reference value and is
1318                  * not currently listed as being checked.
1319                  */
1320                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1321                         entry->map_err_type = MAP_ERR_CHECKED;
1322                         break;
1323                 }
1324         }
1325
1326         put_hash_bucket(bucket, &flags);
1327 }
1328 EXPORT_SYMBOL(debug_dma_mapping_error);
1329
1330 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1331                           size_t size, int direction, bool map_single)
1332 {
1333         struct dma_debug_entry ref = {
1334                 .type           = dma_debug_page,
1335                 .dev            = dev,
1336                 .dev_addr       = addr,
1337                 .size           = size,
1338                 .direction      = direction,
1339         };
1340
1341         if (unlikely(dma_debug_disabled()))
1342                 return;
1343
1344         if (map_single)
1345                 ref.type = dma_debug_single;
1346
1347         check_unmap(&ref);
1348 }
1349 EXPORT_SYMBOL(debug_dma_unmap_page);
1350
1351 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1352                       int nents, int mapped_ents, int direction)
1353 {
1354         struct dma_debug_entry *entry;
1355         struct scatterlist *s;
1356         int i;
1357
1358         if (unlikely(dma_debug_disabled()))
1359                 return;
1360
1361         for_each_sg(sg, s, mapped_ents, i) {
1362                 entry = dma_entry_alloc();
1363                 if (!entry)
1364                         return;
1365
1366                 entry->type           = dma_debug_sg;
1367                 entry->dev            = dev;
1368                 entry->pfn            = page_to_pfn(sg_page(s));
1369                 entry->offset         = s->offset,
1370                 entry->size           = sg_dma_len(s);
1371                 entry->dev_addr       = sg_dma_address(s);
1372                 entry->direction      = direction;
1373                 entry->sg_call_ents   = nents;
1374                 entry->sg_mapped_ents = mapped_ents;
1375
1376                 if (!PageHighMem(sg_page(s))) {
1377                         check_for_stack(dev, sg_virt(s));
1378                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1379                 }
1380
1381                 add_dma_entry(entry);
1382         }
1383 }
1384 EXPORT_SYMBOL(debug_dma_map_sg);
1385
1386 static int get_nr_mapped_entries(struct device *dev,
1387                                  struct dma_debug_entry *ref)
1388 {
1389         struct dma_debug_entry *entry;
1390         struct hash_bucket *bucket;
1391         unsigned long flags;
1392         int mapped_ents;
1393
1394         bucket       = get_hash_bucket(ref, &flags);
1395         entry        = bucket_find_exact(bucket, ref);
1396         mapped_ents  = 0;
1397
1398         if (entry)
1399                 mapped_ents = entry->sg_mapped_ents;
1400         put_hash_bucket(bucket, &flags);
1401
1402         return mapped_ents;
1403 }
1404
1405 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1406                         int nelems, int dir)
1407 {
1408         struct scatterlist *s;
1409         int mapped_ents = 0, i;
1410
1411         if (unlikely(dma_debug_disabled()))
1412                 return;
1413
1414         for_each_sg(sglist, s, nelems, i) {
1415
1416                 struct dma_debug_entry ref = {
1417                         .type           = dma_debug_sg,
1418                         .dev            = dev,
1419                         .pfn            = page_to_pfn(sg_page(s)),
1420                         .offset         = s->offset,
1421                         .dev_addr       = sg_dma_address(s),
1422                         .size           = sg_dma_len(s),
1423                         .direction      = dir,
1424                         .sg_call_ents   = nelems,
1425                 };
1426
1427                 if (mapped_ents && i >= mapped_ents)
1428                         break;
1429
1430                 if (!i)
1431                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1432
1433                 check_unmap(&ref);
1434         }
1435 }
1436 EXPORT_SYMBOL(debug_dma_unmap_sg);
1437
1438 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1439                               dma_addr_t dma_addr, void *virt)
1440 {
1441         struct dma_debug_entry *entry;
1442
1443         if (unlikely(dma_debug_disabled()))
1444                 return;
1445
1446         if (unlikely(virt == NULL))
1447                 return;
1448
1449         entry = dma_entry_alloc();
1450         if (!entry)
1451                 return;
1452
1453         entry->type      = dma_debug_coherent;
1454         entry->dev       = dev;
1455         entry->pfn       = page_to_pfn(virt_to_page(virt));
1456         entry->offset    = (size_t) virt & PAGE_MASK;
1457         entry->size      = size;
1458         entry->dev_addr  = dma_addr;
1459         entry->direction = DMA_BIDIRECTIONAL;
1460
1461         add_dma_entry(entry);
1462 }
1463 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1464
1465 void debug_dma_free_coherent(struct device *dev, size_t size,
1466                          void *virt, dma_addr_t addr)
1467 {
1468         struct dma_debug_entry ref = {
1469                 .type           = dma_debug_coherent,
1470                 .dev            = dev,
1471                 .pfn            = page_to_pfn(virt_to_page(virt)),
1472                 .offset         = (size_t) virt & PAGE_MASK,
1473                 .dev_addr       = addr,
1474                 .size           = size,
1475                 .direction      = DMA_BIDIRECTIONAL,
1476         };
1477
1478         if (unlikely(dma_debug_disabled()))
1479                 return;
1480
1481         check_unmap(&ref);
1482 }
1483 EXPORT_SYMBOL(debug_dma_free_coherent);
1484
1485 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1486                                    size_t size, int direction)
1487 {
1488         struct dma_debug_entry ref;
1489
1490         if (unlikely(dma_debug_disabled()))
1491                 return;
1492
1493         ref.type         = dma_debug_single;
1494         ref.dev          = dev;
1495         ref.dev_addr     = dma_handle;
1496         ref.size         = size;
1497         ref.direction    = direction;
1498         ref.sg_call_ents = 0;
1499
1500         check_sync(dev, &ref, true);
1501 }
1502 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1503
1504 void debug_dma_sync_single_for_device(struct device *dev,
1505                                       dma_addr_t dma_handle, size_t size,
1506                                       int direction)
1507 {
1508         struct dma_debug_entry ref;
1509
1510         if (unlikely(dma_debug_disabled()))
1511                 return;
1512
1513         ref.type         = dma_debug_single;
1514         ref.dev          = dev;
1515         ref.dev_addr     = dma_handle;
1516         ref.size         = size;
1517         ref.direction    = direction;
1518         ref.sg_call_ents = 0;
1519
1520         check_sync(dev, &ref, false);
1521 }
1522 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1523
1524 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1525                                          dma_addr_t dma_handle,
1526                                          unsigned long offset, size_t size,
1527                                          int direction)
1528 {
1529         struct dma_debug_entry ref;
1530
1531         if (unlikely(dma_debug_disabled()))
1532                 return;
1533
1534         ref.type         = dma_debug_single;
1535         ref.dev          = dev;
1536         ref.dev_addr     = dma_handle;
1537         ref.size         = offset + size;
1538         ref.direction    = direction;
1539         ref.sg_call_ents = 0;
1540
1541         check_sync(dev, &ref, true);
1542 }
1543 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1544
1545 void debug_dma_sync_single_range_for_device(struct device *dev,
1546                                             dma_addr_t dma_handle,
1547                                             unsigned long offset,
1548                                             size_t size, int direction)
1549 {
1550         struct dma_debug_entry ref;
1551
1552         if (unlikely(dma_debug_disabled()))
1553                 return;
1554
1555         ref.type         = dma_debug_single;
1556         ref.dev          = dev;
1557         ref.dev_addr     = dma_handle;
1558         ref.size         = offset + size;
1559         ref.direction    = direction;
1560         ref.sg_call_ents = 0;
1561
1562         check_sync(dev, &ref, false);
1563 }
1564 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1565
1566 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1567                                int nelems, int direction)
1568 {
1569         struct scatterlist *s;
1570         int mapped_ents = 0, i;
1571
1572         if (unlikely(dma_debug_disabled()))
1573                 return;
1574
1575         for_each_sg(sg, s, nelems, i) {
1576
1577                 struct dma_debug_entry ref = {
1578                         .type           = dma_debug_sg,
1579                         .dev            = dev,
1580                         .pfn            = page_to_pfn(sg_page(s)),
1581                         .offset         = s->offset,
1582                         .dev_addr       = sg_dma_address(s),
1583                         .size           = sg_dma_len(s),
1584                         .direction      = direction,
1585                         .sg_call_ents   = nelems,
1586                 };
1587
1588                 if (!i)
1589                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1590
1591                 if (i >= mapped_ents)
1592                         break;
1593
1594                 check_sync(dev, &ref, true);
1595         }
1596 }
1597 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1598
1599 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1600                                   int nelems, int direction)
1601 {
1602         struct scatterlist *s;
1603         int mapped_ents = 0, i;
1604
1605         if (unlikely(dma_debug_disabled()))
1606                 return;
1607
1608         for_each_sg(sg, s, nelems, i) {
1609
1610                 struct dma_debug_entry ref = {
1611                         .type           = dma_debug_sg,
1612                         .dev            = dev,
1613                         .pfn            = page_to_pfn(sg_page(s)),
1614                         .offset         = s->offset,
1615                         .dev_addr       = sg_dma_address(s),
1616                         .size           = sg_dma_len(s),
1617                         .direction      = direction,
1618                         .sg_call_ents   = nelems,
1619                 };
1620                 if (!i)
1621                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1622
1623                 if (i >= mapped_ents)
1624                         break;
1625
1626                 check_sync(dev, &ref, false);
1627         }
1628 }
1629 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1630
1631 static int __init dma_debug_driver_setup(char *str)
1632 {
1633         int i;
1634
1635         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1636                 current_driver_name[i] = *str;
1637                 if (*str == 0)
1638                         break;
1639         }
1640
1641         if (current_driver_name[0])
1642                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1643                         current_driver_name);
1644
1645
1646         return 1;
1647 }
1648 __setup("dma_debug_driver=", dma_debug_driver_setup);