blob: a2ed2b76968550cc9d776fe24fc54209eed22e3a [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 Roedel2d62ece2009-01-09 14:10:26 +010020#include <linux/dma-mapping.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010021#include <linux/dma-debug.h>
Joerg Roedel30dfa902009-01-09 12:34:49 +010022#include <linux/spinlock.h>
Joerg Roedel788dcfa2009-01-09 13:13:27 +010023#include <linux/debugfs.h>
Joerg Roedel2d62ece2009-01-09 14:10:26 +010024#include <linux/device.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010025#include <linux/types.h>
Joerg Roedel2d62ece2009-01-09 14:10:26 +010026#include <linux/sched.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010027#include <linux/list.h>
Joerg Roedel6bf07872009-01-09 12:54:42 +010028#include <linux/slab.h>
Joerg Roedelf2f45e52009-01-09 12:19:52 +010029
Joerg Roedel30dfa902009-01-09 12:34:49 +010030#define HASH_SIZE 1024ULL
31#define HASH_FN_SHIFT 13
32#define HASH_FN_MASK (HASH_SIZE - 1)
33
Joerg Roedelf2f45e52009-01-09 12:19:52 +010034enum {
35 dma_debug_single,
36 dma_debug_page,
37 dma_debug_sg,
38 dma_debug_coherent,
39};
40
41struct dma_debug_entry {
42 struct list_head list;
43 struct device *dev;
44 int type;
45 phys_addr_t paddr;
46 u64 dev_addr;
47 u64 size;
48 int direction;
49 int sg_call_ents;
50 int sg_mapped_ents;
51};
52
Joerg Roedel30dfa902009-01-09 12:34:49 +010053struct hash_bucket {
54 struct list_head list;
55 spinlock_t lock;
Joerg Roedel2d62ece2009-01-09 14:10:26 +010056} ____cacheline_aligned_in_smp;
Joerg Roedel30dfa902009-01-09 12:34:49 +010057
58/* Hash list to save the allocated dma addresses */
59static struct hash_bucket dma_entry_hash[HASH_SIZE];
Joerg Roedel3b1e79e2009-01-09 12:42:46 +010060/* List of pre-allocated dma_debug_entry's */
61static LIST_HEAD(free_entries);
62/* Lock for the list above */
63static DEFINE_SPINLOCK(free_entries_lock);
64
65/* Global disable flag - will be set in case of an error */
66static bool global_disable __read_mostly;
67
Joerg Roedel788dcfa2009-01-09 13:13:27 +010068/* Global error count */
69static u32 error_count;
70
71/* Global error show enable*/
72static u32 show_all_errors __read_mostly;
73/* Number of errors to show */
74static u32 show_num_errors = 1;
75
Joerg Roedel3b1e79e2009-01-09 12:42:46 +010076static u32 num_free_entries;
77static u32 min_free_entries;
Joerg Roedel30dfa902009-01-09 12:34:49 +010078
Joerg Roedel59d3daa2009-01-09 13:01:56 +010079/* number of preallocated entries requested by kernel cmdline */
80static u32 req_entries;
81
Joerg Roedel788dcfa2009-01-09 13:13:27 +010082/* debugfs dentry's for the stuff above */
83static struct dentry *dma_debug_dent __read_mostly;
84static struct dentry *global_disable_dent __read_mostly;
85static struct dentry *error_count_dent __read_mostly;
86static struct dentry *show_all_errors_dent __read_mostly;
87static struct dentry *show_num_errors_dent __read_mostly;
88static struct dentry *num_free_entries_dent __read_mostly;
89static struct dentry *min_free_entries_dent __read_mostly;
90
Joerg Roedel2d62ece2009-01-09 14:10:26 +010091static const char *type2name[4] = { "single", "page",
92 "scather-gather", "coherent" };
93
94static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
95 "DMA_FROM_DEVICE", "DMA_NONE" };
96
97/*
98 * The access to some variables in this macro is racy. We can't use atomic_t
99 * here because all these variables are exported to debugfs. Some of them even
100 * writeable. This is also the reason why a lock won't help much. But anyway,
101 * the races are no big deal. Here is why:
102 *
103 * error_count: the addition is racy, but the worst thing that can happen is
104 * that we don't count some errors
105 * show_num_errors: the subtraction is racy. Also no big deal because in
106 * worst case this will result in one warning more in the
107 * system log than the user configured. This variable is
108 * writeable via debugfs.
109 */
110#define err_printk(dev, format, arg...) do { \
111 error_count += 1; \
112 if (show_all_errors || show_num_errors > 0) { \
113 WARN(1, "%s %s: " format, \
114 dev_driver_string(dev), \
115 dev_name(dev) , ## arg); \
116 } \
117 if (!show_all_errors && show_num_errors > 0) \
118 show_num_errors -= 1; \
119 } while (0);
120
Joerg Roedel30dfa902009-01-09 12:34:49 +0100121/*
122 * Hash related functions
123 *
124 * Every DMA-API request is saved into a struct dma_debug_entry. To
125 * have quick access to these structs they are stored into a hash.
126 */
127static int hash_fn(struct dma_debug_entry *entry)
128{
129 /*
130 * Hash function is based on the dma address.
131 * We use bits 20-27 here as the index into the hash
132 */
133 return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
134}
135
136/*
137 * Request exclusive access to a hash bucket for a given dma_debug_entry.
138 */
139static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
140 unsigned long *flags)
141{
142 int idx = hash_fn(entry);
143 unsigned long __flags;
144
145 spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
146 *flags = __flags;
147 return &dma_entry_hash[idx];
148}
149
150/*
151 * Give up exclusive access to the hash bucket
152 */
153static void put_hash_bucket(struct hash_bucket *bucket,
154 unsigned long *flags)
155{
156 unsigned long __flags = *flags;
157
158 spin_unlock_irqrestore(&bucket->lock, __flags);
159}
160
161/*
162 * Search a given entry in the hash bucket list
163 */
164static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
165 struct dma_debug_entry *ref)
166{
167 struct dma_debug_entry *entry;
168
169 list_for_each_entry(entry, &bucket->list, list) {
170 if ((entry->dev_addr == ref->dev_addr) &&
171 (entry->dev == ref->dev))
172 return entry;
173 }
174
175 return NULL;
176}
177
178/*
179 * Add an entry to a hash bucket
180 */
181static void hash_bucket_add(struct hash_bucket *bucket,
182 struct dma_debug_entry *entry)
183{
184 list_add_tail(&entry->list, &bucket->list);
185}
186
187/*
188 * Remove entry from a hash bucket list
189 */
190static void hash_bucket_del(struct dma_debug_entry *entry)
191{
192 list_del(&entry->list);
193}
194
195/*
196 * Wrapper function for adding an entry to the hash.
197 * This function takes care of locking itself.
198 */
199static void add_dma_entry(struct dma_debug_entry *entry)
200{
201 struct hash_bucket *bucket;
202 unsigned long flags;
203
204 bucket = get_hash_bucket(entry, &flags);
205 hash_bucket_add(bucket, entry);
206 put_hash_bucket(bucket, &flags);
207}
208
Joerg Roedel3b1e79e2009-01-09 12:42:46 +0100209/* struct dma_entry allocator
210 *
211 * The next two functions implement the allocator for
212 * struct dma_debug_entries.
213 */
214static struct dma_debug_entry *dma_entry_alloc(void)
215{
216 struct dma_debug_entry *entry = NULL;
217 unsigned long flags;
218
219 spin_lock_irqsave(&free_entries_lock, flags);
220
221 if (list_empty(&free_entries)) {
222 printk(KERN_ERR "DMA-API: debugging out of memory "
223 "- disabling\n");
224 global_disable = true;
225 goto out;
226 }
227
228 entry = list_entry(free_entries.next, struct dma_debug_entry, list);
229 list_del(&entry->list);
230 memset(entry, 0, sizeof(*entry));
231
232 num_free_entries -= 1;
233 if (num_free_entries < min_free_entries)
234 min_free_entries = num_free_entries;
235
236out:
237 spin_unlock_irqrestore(&free_entries_lock, flags);
238
239 return entry;
240}
241
242static void dma_entry_free(struct dma_debug_entry *entry)
243{
244 unsigned long flags;
245
246 /*
247 * add to beginning of the list - this way the entries are
248 * more likely cache hot when they are reallocated.
249 */
250 spin_lock_irqsave(&free_entries_lock, flags);
251 list_add(&entry->list, &free_entries);
252 num_free_entries += 1;
253 spin_unlock_irqrestore(&free_entries_lock, flags);
254}
255
Joerg Roedel6bf07872009-01-09 12:54:42 +0100256/*
257 * DMA-API debugging init code
258 *
259 * The init code does two things:
260 * 1. Initialize core data structures
261 * 2. Preallocate a given number of dma_debug_entry structs
262 */
263
264static int prealloc_memory(u32 num_entries)
265{
266 struct dma_debug_entry *entry, *next_entry;
267 int i;
268
269 for (i = 0; i < num_entries; ++i) {
270 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
271 if (!entry)
272 goto out_err;
273
274 list_add_tail(&entry->list, &free_entries);
275 }
276
277 num_free_entries = num_entries;
278 min_free_entries = num_entries;
279
280 printk(KERN_INFO "DMA-API: preallocated %d debug entries\n",
281 num_entries);
282
283 return 0;
284
285out_err:
286
287 list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
288 list_del(&entry->list);
289 kfree(entry);
290 }
291
292 return -ENOMEM;
293}
294
Joerg Roedel788dcfa2009-01-09 13:13:27 +0100295static int dma_debug_fs_init(void)
296{
297 dma_debug_dent = debugfs_create_dir("dma-api", NULL);
298 if (!dma_debug_dent) {
299 printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
300 return -ENOMEM;
301 }
302
303 global_disable_dent = debugfs_create_bool("disabled", 0444,
304 dma_debug_dent,
305 (u32 *)&global_disable);
306 if (!global_disable_dent)
307 goto out_err;
308
309 error_count_dent = debugfs_create_u32("error_count", 0444,
310 dma_debug_dent, &error_count);
311 if (!error_count_dent)
312 goto out_err;
313
314 show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
315 dma_debug_dent,
316 &show_all_errors);
317 if (!show_all_errors_dent)
318 goto out_err;
319
320 show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
321 dma_debug_dent,
322 &show_num_errors);
323 if (!show_num_errors_dent)
324 goto out_err;
325
326 num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
327 dma_debug_dent,
328 &num_free_entries);
329 if (!num_free_entries_dent)
330 goto out_err;
331
332 min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
333 dma_debug_dent,
334 &min_free_entries);
335 if (!min_free_entries_dent)
336 goto out_err;
337
338 return 0;
339
340out_err:
341 debugfs_remove_recursive(dma_debug_dent);
342
343 return -ENOMEM;
344}
345
346
Joerg Roedel6bf07872009-01-09 12:54:42 +0100347/*
348 * Let the architectures decide how many entries should be preallocated.
349 */
350void dma_debug_init(u32 num_entries)
351{
352 int i;
353
354 if (global_disable)
355 return;
356
357 for (i = 0; i < HASH_SIZE; ++i) {
358 INIT_LIST_HEAD(&dma_entry_hash[i].list);
359 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
360 }
361
Joerg Roedel788dcfa2009-01-09 13:13:27 +0100362 if (dma_debug_fs_init() != 0) {
363 printk(KERN_ERR "DMA-API: error creating debugfs entries "
364 "- disabling\n");
365 global_disable = true;
366
367 return;
368 }
369
Joerg Roedel59d3daa2009-01-09 13:01:56 +0100370 if (req_entries)
371 num_entries = req_entries;
372
Joerg Roedel6bf07872009-01-09 12:54:42 +0100373 if (prealloc_memory(num_entries) != 0) {
374 printk(KERN_ERR "DMA-API: debugging out of memory error "
375 "- disabled\n");
376 global_disable = true;
377
378 return;
379 }
380
381 printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
382}
383
Joerg Roedel59d3daa2009-01-09 13:01:56 +0100384static __init int dma_debug_cmdline(char *str)
385{
386 if (!str)
387 return -EINVAL;
388
389 if (strncmp(str, "off", 3) == 0) {
390 printk(KERN_INFO "DMA-API: debugging disabled on kernel "
391 "command line\n");
392 global_disable = true;
393 }
394
395 return 0;
396}
397
398static __init int dma_debug_entries_cmdline(char *str)
399{
400 int res;
401
402 if (!str)
403 return -EINVAL;
404
405 res = get_option(&str, &req_entries);
406
407 if (!res)
408 req_entries = 0;
409
410 return 0;
411}
412
413__setup("dma_debug=", dma_debug_cmdline);
414__setup("dma_debug_entries=", dma_debug_entries_cmdline);
415
Joerg Roedel2d62ece2009-01-09 14:10:26 +0100416static void check_unmap(struct dma_debug_entry *ref)
417{
418 struct dma_debug_entry *entry;
419 struct hash_bucket *bucket;
420 unsigned long flags;
421
422 if (dma_mapping_error(ref->dev, ref->dev_addr))
423 return;
424
425 bucket = get_hash_bucket(ref, &flags);
426 entry = hash_bucket_find(bucket, ref);
427
428 if (!entry) {
429 err_printk(ref->dev, "DMA-API: device driver tries "
430 "to free DMA memory it has not allocated "
431 "[device address=0x%016llx] [size=%llu bytes]\n",
432 ref->dev_addr, ref->size);
433 goto out;
434 }
435
436 if (ref->size != entry->size) {
437 err_printk(ref->dev, "DMA-API: device driver frees "
438 "DMA memory with different size "
439 "[device address=0x%016llx] [map size=%llu bytes] "
440 "[unmap size=%llu bytes]\n",
441 ref->dev_addr, entry->size, ref->size);
442 }
443
444 if (ref->type != entry->type) {
445 err_printk(ref->dev, "DMA-API: device driver frees "
446 "DMA memory with wrong function "
447 "[device address=0x%016llx] [size=%llu bytes] "
448 "[mapped as %s] [unmapped as %s]\n",
449 ref->dev_addr, ref->size,
450 type2name[entry->type], type2name[ref->type]);
451 } else if ((entry->type == dma_debug_coherent) &&
452 (ref->paddr != entry->paddr)) {
453 err_printk(ref->dev, "DMA-API: device driver frees "
454 "DMA memory with different CPU address "
455 "[device address=0x%016llx] [size=%llu bytes] "
456 "[cpu alloc address=%p] [cpu free address=%p]",
457 ref->dev_addr, ref->size,
458 (void *)entry->paddr, (void *)ref->paddr);
459 }
460
461 if (ref->sg_call_ents && ref->type == dma_debug_sg &&
462 ref->sg_call_ents != entry->sg_call_ents) {
463 err_printk(ref->dev, "DMA-API: device driver frees "
464 "DMA sg list with different entry count "
465 "[map count=%d] [unmap count=%d]\n",
466 entry->sg_call_ents, ref->sg_call_ents);
467 }
468
469 /*
470 * This may be no bug in reality - but most implementations of the
471 * DMA API don't handle this properly, so check for it here
472 */
473 if (ref->direction != entry->direction) {
474 err_printk(ref->dev, "DMA-API: device driver frees "
475 "DMA memory with different direction "
476 "[device address=0x%016llx] [size=%llu bytes] "
477 "[mapped with %s] [unmapped with %s]\n",
478 ref->dev_addr, ref->size,
479 dir2name[entry->direction],
480 dir2name[ref->direction]);
481 }
482
483 hash_bucket_del(entry);
484 dma_entry_free(entry);
485
486out:
487 put_hash_bucket(bucket, &flags);
488}
489
490static void check_for_stack(struct device *dev, void *addr)
491{
492 if (object_is_on_stack(addr))
493 err_printk(dev, "DMA-API: device driver maps memory from stack"
494 " [addr=%p]\n", addr);
495}
496
497static void check_sync(struct device *dev, dma_addr_t addr,
498 u64 size, u64 offset, int direction, bool to_cpu)
499{
500 struct dma_debug_entry ref = {
501 .dev = dev,
502 .dev_addr = addr,
503 .size = size,
504 .direction = direction,
505 };
506 struct dma_debug_entry *entry;
507 struct hash_bucket *bucket;
508 unsigned long flags;
509
510 bucket = get_hash_bucket(&ref, &flags);
511
512 entry = hash_bucket_find(bucket, &ref);
513
514 if (!entry) {
515 err_printk(dev, "DMA-API: device driver tries "
516 "to sync DMA memory it has not allocated "
517 "[device address=0x%016llx] [size=%llu bytes]\n",
518 addr, size);
519 goto out;
520 }
521
522 if ((offset + size) > entry->size) {
523 err_printk(dev, "DMA-API: device driver syncs"
524 " DMA memory outside allocated range "
525 "[device address=0x%016llx] "
526 "[allocation size=%llu bytes] [sync offset=%llu] "
527 "[sync size=%llu]\n", entry->dev_addr, entry->size,
528 offset, size);
529 }
530
531 if (direction != entry->direction) {
532 err_printk(dev, "DMA-API: device driver syncs "
533 "DMA memory with different direction "
534 "[device address=0x%016llx] [size=%llu bytes] "
535 "[mapped with %s] [synced with %s]\n",
536 addr, entry->size,
537 dir2name[entry->direction],
538 dir2name[direction]);
539 }
540
541 if (entry->direction == DMA_BIDIRECTIONAL)
542 goto out;
543
544 if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
545 !(direction == DMA_TO_DEVICE))
546 err_printk(dev, "DMA-API: device driver syncs "
547 "device read-only DMA memory for cpu "
548 "[device address=0x%016llx] [size=%llu bytes] "
549 "[mapped with %s] [synced with %s]\n",
550 addr, entry->size,
551 dir2name[entry->direction],
552 dir2name[direction]);
553
554 if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
555 !(direction == DMA_FROM_DEVICE))
556 err_printk(dev, "DMA-API: device driver syncs "
557 "device write-only DMA memory to device "
558 "[device address=0x%016llx] [size=%llu bytes] "
559 "[mapped with %s] [synced with %s]\n",
560 addr, entry->size,
561 dir2name[entry->direction],
562 dir2name[direction]);
563
564out:
565 put_hash_bucket(bucket, &flags);
566
567}
568
Joerg Roedelf62bc982009-01-09 14:14:49 +0100569void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
570 size_t size, int direction, dma_addr_t dma_addr,
571 bool map_single)
572{
573 struct dma_debug_entry *entry;
574
575 if (unlikely(global_disable))
576 return;
577
578 if (unlikely(dma_mapping_error(dev, dma_addr)))
579 return;
580
581 entry = dma_entry_alloc();
582 if (!entry)
583 return;
584
585 entry->dev = dev;
586 entry->type = dma_debug_page;
587 entry->paddr = page_to_phys(page) + offset;
588 entry->dev_addr = dma_addr;
589 entry->size = size;
590 entry->direction = direction;
591
592 if (map_single) {
593 entry->type = dma_debug_single;
594 check_for_stack(dev, page_address(page) + offset);
595 }
596
597 add_dma_entry(entry);
598}
599EXPORT_SYMBOL(debug_dma_map_page);
600
601void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
602 size_t size, int direction, bool map_single)
603{
604 struct dma_debug_entry ref = {
605 .type = dma_debug_page,
606 .dev = dev,
607 .dev_addr = addr,
608 .size = size,
609 .direction = direction,
610 };
611
612 if (unlikely(global_disable))
613 return;
614
615 if (map_single)
616 ref.type = dma_debug_single;
617
618 check_unmap(&ref);
619}
620EXPORT_SYMBOL(debug_dma_unmap_page);
621