blob: 26e40e93e0f2f70dad23a32278de754a1063957a [file] [log] [blame]
Joerg Roedelf2f45e52009-01-09 12:19:52 +01001/*
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
Joerg Roedel972aa452009-01-09 14:19:54 +010020#include <linux/scatterlist.h>
Joerg Roedel2d62ece2009-01-09 14:10:26 +010021#include <linux/dma-mapping.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010022#include <linux/dma-debug.h>
Joerg Roedel30dfa902009-01-09 12:34:49 +010023#include <linux/spinlock.h>
Joerg Roedel788dcfa2009-01-09 13:13:27 +010024#include <linux/debugfs.h>
Joerg Roedel2d62ece2009-01-09 14:10:26 +010025#include <linux/device.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010026#include <linux/types.h>
Joerg Roedel2d62ece2009-01-09 14:10:26 +010027#include <linux/sched.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010028#include <linux/list.h>
Joerg Roedel6bf07872009-01-09 12:54:42 +010029#include <linux/slab.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010030
Joerg Roedel30dfa902009-01-09 12:34:49 +010031#define HASH_SIZE 1024ULL
32#define HASH_FN_SHIFT 13
33#define HASH_FN_MASK (HASH_SIZE - 1)
34
Joerg Roedelf2f45e52009-01-09 12:19:52 +010035enum {
36 dma_debug_single,
37 dma_debug_page,
38 dma_debug_sg,
39 dma_debug_coherent,
40};
41
42struct 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
Joerg Roedel30dfa902009-01-09 12:34:49 +010054struct hash_bucket {
55 struct list_head list;
56 spinlock_t lock;
Joerg Roedel2d62ece2009-01-09 14:10:26 +010057} ____cacheline_aligned_in_smp;
Joerg Roedel30dfa902009-01-09 12:34:49 +010058
59/* Hash list to save the allocated dma addresses */
60static struct hash_bucket dma_entry_hash[HASH_SIZE];
Joerg Roedel3b1e79e2009-01-09 12:42:46 +010061/* List of pre-allocated dma_debug_entry's */
62static LIST_HEAD(free_entries);
63/* Lock for the list above */
64static DEFINE_SPINLOCK(free_entries_lock);
65
66/* Global disable flag - will be set in case of an error */
67static bool global_disable __read_mostly;
68
Joerg Roedel788dcfa2009-01-09 13:13:27 +010069/* Global error count */
70static u32 error_count;
71
72/* Global error show enable*/
73static u32 show_all_errors __read_mostly;
74/* Number of errors to show */
75static u32 show_num_errors = 1;
76
Joerg Roedel3b1e79e2009-01-09 12:42:46 +010077static u32 num_free_entries;
78static u32 min_free_entries;
Joerg Roedel30dfa902009-01-09 12:34:49 +010079
Joerg Roedel59d3daa2009-01-09 13:01:56 +010080/* number of preallocated entries requested by kernel cmdline */
81static u32 req_entries;
82
Joerg Roedel788dcfa2009-01-09 13:13:27 +010083/* debugfs dentry's for the stuff above */
84static struct dentry *dma_debug_dent __read_mostly;
85static struct dentry *global_disable_dent __read_mostly;
86static struct dentry *error_count_dent __read_mostly;
87static struct dentry *show_all_errors_dent __read_mostly;
88static struct dentry *show_num_errors_dent __read_mostly;
89static struct dentry *num_free_entries_dent __read_mostly;
90static struct dentry *min_free_entries_dent __read_mostly;
91
Joerg Roedel2d62ece2009-01-09 14:10:26 +010092static const char *type2name[4] = { "single", "page",
93 "scather-gather", "coherent" };
94
95static 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
Joerg Roedel30dfa902009-01-09 12:34:49 +0100122/*
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 */
128static 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 */
140static 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 */
154static 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 */
165static 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 */
182static 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 */
191static void hash_bucket_del(struct dma_debug_entry *entry)
192{
193 list_del(&entry->list);
194}
195
196/*
197 * Wrapper function for adding an entry to the hash.
198 * This function takes care of locking itself.
199 */
200static void add_dma_entry(struct dma_debug_entry *entry)
201{
202 struct hash_bucket *bucket;
203 unsigned long flags;
204
205 bucket = get_hash_bucket(entry, &flags);
206 hash_bucket_add(bucket, entry);
207 put_hash_bucket(bucket, &flags);
208}
209
Joerg Roedel3b1e79e2009-01-09 12:42:46 +0100210/* struct dma_entry allocator
211 *
212 * The next two functions implement the allocator for
213 * struct dma_debug_entries.
214 */
215static struct dma_debug_entry *dma_entry_alloc(void)
216{
217 struct dma_debug_entry *entry = NULL;
218 unsigned long flags;
219
220 spin_lock_irqsave(&free_entries_lock, flags);
221
222 if (list_empty(&free_entries)) {
223 printk(KERN_ERR "DMA-API: debugging out of memory "
224 "- disabling\n");
225 global_disable = true;
226 goto out;
227 }
228
229 entry = list_entry(free_entries.next, struct dma_debug_entry, list);
230 list_del(&entry->list);
231 memset(entry, 0, sizeof(*entry));
232
233 num_free_entries -= 1;
234 if (num_free_entries < min_free_entries)
235 min_free_entries = num_free_entries;
236
237out:
238 spin_unlock_irqrestore(&free_entries_lock, flags);
239
240 return entry;
241}
242
243static void dma_entry_free(struct dma_debug_entry *entry)
244{
245 unsigned long flags;
246
247 /*
248 * add to beginning of the list - this way the entries are
249 * more likely cache hot when they are reallocated.
250 */
251 spin_lock_irqsave(&free_entries_lock, flags);
252 list_add(&entry->list, &free_entries);
253 num_free_entries += 1;
254 spin_unlock_irqrestore(&free_entries_lock, flags);
255}
256
Joerg Roedel6bf07872009-01-09 12:54:42 +0100257/*
258 * DMA-API debugging init code
259 *
260 * The init code does two things:
261 * 1. Initialize core data structures
262 * 2. Preallocate a given number of dma_debug_entry structs
263 */
264
265static int prealloc_memory(u32 num_entries)
266{
267 struct dma_debug_entry *entry, *next_entry;
268 int i;
269
270 for (i = 0; i < num_entries; ++i) {
271 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
272 if (!entry)
273 goto out_err;
274
275 list_add_tail(&entry->list, &free_entries);
276 }
277
278 num_free_entries = num_entries;
279 min_free_entries = num_entries;
280
281 printk(KERN_INFO "DMA-API: preallocated %d debug entries\n",
282 num_entries);
283
284 return 0;
285
286out_err:
287
288 list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
289 list_del(&entry->list);
290 kfree(entry);
291 }
292
293 return -ENOMEM;
294}
295
Joerg Roedel788dcfa2009-01-09 13:13:27 +0100296static int dma_debug_fs_init(void)
297{
298 dma_debug_dent = debugfs_create_dir("dma-api", NULL);
299 if (!dma_debug_dent) {
300 printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
301 return -ENOMEM;
302 }
303
304 global_disable_dent = debugfs_create_bool("disabled", 0444,
305 dma_debug_dent,
306 (u32 *)&global_disable);
307 if (!global_disable_dent)
308 goto out_err;
309
310 error_count_dent = debugfs_create_u32("error_count", 0444,
311 dma_debug_dent, &error_count);
312 if (!error_count_dent)
313 goto out_err;
314
315 show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
316 dma_debug_dent,
317 &show_all_errors);
318 if (!show_all_errors_dent)
319 goto out_err;
320
321 show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
322 dma_debug_dent,
323 &show_num_errors);
324 if (!show_num_errors_dent)
325 goto out_err;
326
327 num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
328 dma_debug_dent,
329 &num_free_entries);
330 if (!num_free_entries_dent)
331 goto out_err;
332
333 min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
334 dma_debug_dent,
335 &min_free_entries);
336 if (!min_free_entries_dent)
337 goto out_err;
338
339 return 0;
340
341out_err:
342 debugfs_remove_recursive(dma_debug_dent);
343
344 return -ENOMEM;
345}
346
347
Joerg Roedel6bf07872009-01-09 12:54:42 +0100348/*
349 * Let the architectures decide how many entries should be preallocated.
350 */
351void dma_debug_init(u32 num_entries)
352{
353 int i;
354
355 if (global_disable)
356 return;
357
358 for (i = 0; i < HASH_SIZE; ++i) {
359 INIT_LIST_HEAD(&dma_entry_hash[i].list);
360 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
361 }
362
Joerg Roedel788dcfa2009-01-09 13:13:27 +0100363 if (dma_debug_fs_init() != 0) {
364 printk(KERN_ERR "DMA-API: error creating debugfs entries "
365 "- disabling\n");
366 global_disable = true;
367
368 return;
369 }
370
Joerg Roedel59d3daa2009-01-09 13:01:56 +0100371 if (req_entries)
372 num_entries = req_entries;
373
Joerg Roedel6bf07872009-01-09 12:54:42 +0100374 if (prealloc_memory(num_entries) != 0) {
375 printk(KERN_ERR "DMA-API: debugging out of memory error "
376 "- disabled\n");
377 global_disable = true;
378
379 return;
380 }
381
382 printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
383}
384
Joerg Roedel59d3daa2009-01-09 13:01:56 +0100385static __init int dma_debug_cmdline(char *str)
386{
387 if (!str)
388 return -EINVAL;
389
390 if (strncmp(str, "off", 3) == 0) {
391 printk(KERN_INFO "DMA-API: debugging disabled on kernel "
392 "command line\n");
393 global_disable = true;
394 }
395
396 return 0;
397}
398
399static __init int dma_debug_entries_cmdline(char *str)
400{
401 int res;
402
403 if (!str)
404 return -EINVAL;
405
406 res = get_option(&str, &req_entries);
407
408 if (!res)
409 req_entries = 0;
410
411 return 0;
412}
413
414__setup("dma_debug=", dma_debug_cmdline);
415__setup("dma_debug_entries=", dma_debug_entries_cmdline);
416
Joerg Roedel2d62ece2009-01-09 14:10:26 +0100417static void check_unmap(struct dma_debug_entry *ref)
418{
419 struct dma_debug_entry *entry;
420 struct hash_bucket *bucket;
421 unsigned long flags;
422
423 if (dma_mapping_error(ref->dev, ref->dev_addr))
424 return;
425
426 bucket = get_hash_bucket(ref, &flags);
427 entry = hash_bucket_find(bucket, ref);
428
429 if (!entry) {
430 err_printk(ref->dev, "DMA-API: device driver tries "
431 "to free DMA memory it has not allocated "
432 "[device address=0x%016llx] [size=%llu bytes]\n",
433 ref->dev_addr, ref->size);
434 goto out;
435 }
436
437 if (ref->size != entry->size) {
438 err_printk(ref->dev, "DMA-API: device driver frees "
439 "DMA memory with different size "
440 "[device address=0x%016llx] [map size=%llu bytes] "
441 "[unmap size=%llu bytes]\n",
442 ref->dev_addr, entry->size, ref->size);
443 }
444
445 if (ref->type != entry->type) {
446 err_printk(ref->dev, "DMA-API: device driver frees "
447 "DMA memory with wrong function "
448 "[device address=0x%016llx] [size=%llu bytes] "
449 "[mapped as %s] [unmapped as %s]\n",
450 ref->dev_addr, ref->size,
451 type2name[entry->type], type2name[ref->type]);
452 } else if ((entry->type == dma_debug_coherent) &&
453 (ref->paddr != entry->paddr)) {
454 err_printk(ref->dev, "DMA-API: device driver frees "
455 "DMA memory with different CPU address "
456 "[device address=0x%016llx] [size=%llu bytes] "
457 "[cpu alloc address=%p] [cpu free address=%p]",
458 ref->dev_addr, ref->size,
459 (void *)entry->paddr, (void *)ref->paddr);
460 }
461
462 if (ref->sg_call_ents && ref->type == dma_debug_sg &&
463 ref->sg_call_ents != entry->sg_call_ents) {
464 err_printk(ref->dev, "DMA-API: device driver frees "
465 "DMA sg list with different entry count "
466 "[map count=%d] [unmap count=%d]\n",
467 entry->sg_call_ents, ref->sg_call_ents);
468 }
469
470 /*
471 * This may be no bug in reality - but most implementations of the
472 * DMA API don't handle this properly, so check for it here
473 */
474 if (ref->direction != entry->direction) {
475 err_printk(ref->dev, "DMA-API: device driver frees "
476 "DMA memory with different direction "
477 "[device address=0x%016llx] [size=%llu bytes] "
478 "[mapped with %s] [unmapped with %s]\n",
479 ref->dev_addr, ref->size,
480 dir2name[entry->direction],
481 dir2name[ref->direction]);
482 }
483
484 hash_bucket_del(entry);
485 dma_entry_free(entry);
486
487out:
488 put_hash_bucket(bucket, &flags);
489}
490
491static void check_for_stack(struct device *dev, void *addr)
492{
493 if (object_is_on_stack(addr))
494 err_printk(dev, "DMA-API: device driver maps memory from stack"
495 " [addr=%p]\n", addr);
496}
497
498static void check_sync(struct device *dev, dma_addr_t addr,
499 u64 size, u64 offset, int direction, bool to_cpu)
500{
501 struct dma_debug_entry ref = {
502 .dev = dev,
503 .dev_addr = addr,
504 .size = size,
505 .direction = direction,
506 };
507 struct dma_debug_entry *entry;
508 struct hash_bucket *bucket;
509 unsigned long flags;
510
511 bucket = get_hash_bucket(&ref, &flags);
512
513 entry = hash_bucket_find(bucket, &ref);
514
515 if (!entry) {
516 err_printk(dev, "DMA-API: device driver tries "
517 "to sync DMA memory it has not allocated "
518 "[device address=0x%016llx] [size=%llu bytes]\n",
519 addr, size);
520 goto out;
521 }
522
523 if ((offset + size) > entry->size) {
524 err_printk(dev, "DMA-API: device driver syncs"
525 " DMA memory outside allocated range "
526 "[device address=0x%016llx] "
527 "[allocation size=%llu bytes] [sync offset=%llu] "
528 "[sync size=%llu]\n", entry->dev_addr, entry->size,
529 offset, size);
530 }
531
532 if (direction != entry->direction) {
533 err_printk(dev, "DMA-API: device driver syncs "
534 "DMA memory with different direction "
535 "[device address=0x%016llx] [size=%llu bytes] "
536 "[mapped with %s] [synced with %s]\n",
537 addr, entry->size,
538 dir2name[entry->direction],
539 dir2name[direction]);
540 }
541
542 if (entry->direction == DMA_BIDIRECTIONAL)
543 goto out;
544
545 if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
546 !(direction == DMA_TO_DEVICE))
547 err_printk(dev, "DMA-API: device driver syncs "
548 "device read-only DMA memory for cpu "
549 "[device address=0x%016llx] [size=%llu bytes] "
550 "[mapped with %s] [synced with %s]\n",
551 addr, entry->size,
552 dir2name[entry->direction],
553 dir2name[direction]);
554
555 if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
556 !(direction == DMA_FROM_DEVICE))
557 err_printk(dev, "DMA-API: device driver syncs "
558 "device write-only DMA memory to device "
559 "[device address=0x%016llx] [size=%llu bytes] "
560 "[mapped with %s] [synced with %s]\n",
561 addr, entry->size,
562 dir2name[entry->direction],
563 dir2name[direction]);
564
565out:
566 put_hash_bucket(bucket, &flags);
567
568}
569
Joerg Roedelf62bc982009-01-09 14:14:49 +0100570void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
571 size_t size, int direction, dma_addr_t dma_addr,
572 bool map_single)
573{
574 struct dma_debug_entry *entry;
575
576 if (unlikely(global_disable))
577 return;
578
579 if (unlikely(dma_mapping_error(dev, dma_addr)))
580 return;
581
582 entry = dma_entry_alloc();
583 if (!entry)
584 return;
585
586 entry->dev = dev;
587 entry->type = dma_debug_page;
588 entry->paddr = page_to_phys(page) + offset;
589 entry->dev_addr = dma_addr;
590 entry->size = size;
591 entry->direction = direction;
592
593 if (map_single) {
594 entry->type = dma_debug_single;
595 check_for_stack(dev, page_address(page) + offset);
596 }
597
598 add_dma_entry(entry);
599}
600EXPORT_SYMBOL(debug_dma_map_page);
601
602void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
603 size_t size, int direction, bool map_single)
604{
605 struct dma_debug_entry ref = {
606 .type = dma_debug_page,
607 .dev = dev,
608 .dev_addr = addr,
609 .size = size,
610 .direction = direction,
611 };
612
613 if (unlikely(global_disable))
614 return;
615
616 if (map_single)
617 ref.type = dma_debug_single;
618
619 check_unmap(&ref);
620}
621EXPORT_SYMBOL(debug_dma_unmap_page);
622
Joerg Roedel972aa452009-01-09 14:19:54 +0100623void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
624 int nents, int mapped_ents, int direction)
625{
626 struct dma_debug_entry *entry;
627 struct scatterlist *s;
628 int i;
629
630 if (unlikely(global_disable))
631 return;
632
633 for_each_sg(sg, s, mapped_ents, i) {
634 entry = dma_entry_alloc();
635 if (!entry)
636 return;
637
638 entry->type = dma_debug_sg;
639 entry->dev = dev;
640 entry->paddr = sg_phys(s);
641 entry->size = s->length;
642 entry->dev_addr = s->dma_address;
643 entry->direction = direction;
644 entry->sg_call_ents = nents;
645 entry->sg_mapped_ents = mapped_ents;
646
647 check_for_stack(dev, sg_virt(s));
648
649 add_dma_entry(entry);
650 }
651}
652EXPORT_SYMBOL(debug_dma_map_sg);
653
654void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
655 int nelems, int dir)
656{
657 struct dma_debug_entry *entry;
658 struct scatterlist *s;
659 int mapped_ents = 0, i;
660 unsigned long flags;
661
662 if (unlikely(global_disable))
663 return;
664
665 for_each_sg(sglist, s, nelems, i) {
666
667 struct dma_debug_entry ref = {
668 .type = dma_debug_sg,
669 .dev = dev,
670 .paddr = sg_phys(s),
671 .dev_addr = s->dma_address,
672 .size = s->length,
673 .direction = dir,
674 .sg_call_ents = 0,
675 };
676
677 if (mapped_ents && i >= mapped_ents)
678 break;
679
680 if (mapped_ents == 0) {
681 struct hash_bucket *bucket;
682 ref.sg_call_ents = nelems;
683 bucket = get_hash_bucket(&ref, &flags);
684 entry = hash_bucket_find(bucket, &ref);
685 if (entry)
686 mapped_ents = entry->sg_mapped_ents;
687 put_hash_bucket(bucket, &flags);
688 }
689
690 check_unmap(&ref);
691 }
692}
693EXPORT_SYMBOL(debug_dma_unmap_sg);
694