summaryrefslogtreecommitdiff
path: root/arch/arm/mm/dma-mapping.c
blob: 0549bee68a6724dd307fa584f925828a9bdbc737 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/arch/arm/mm/dma-mapping.c
 *
 *  Copyright (C) 2000-2004 Russell King
 *
 *  DMA uncached mapping support.
 */
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/genalloc.h>
#include <linux/gfp.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/dma-direct.h>
#include <linux/dma-map-ops.h>
#include <linux/highmem.h>
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/iommu.h>
#include <linux/io.h>
#include <linux/vmalloc.h>
#include <linux/sizes.h>
#include <linux/cma.h>

#include <asm/page.h>
#include <asm/highmem.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/mach/arch.h>
#include <asm/dma-iommu.h>
#include <asm/mach/map.h>
#include <asm/system_info.h>
#include <asm/xen/xen-ops.h>

#include "dma.h"
#include "mm.h"

struct arm_dma_alloc_args {
	struct device *dev;
	size_t size;
	gfp_t gfp;
	pgprot_t prot;
	const void *caller;
	bool want_vaddr;
	int coherent_flag;
};

struct arm_dma_free_args {
	struct device *dev;
	size_t size;
	void *cpu_addr;
	struct page *page;
	bool want_vaddr;
};

#define NORMAL	    0
#define COHERENT    1

struct arm_dma_allocator {
	void *(*alloc)(struct arm_dma_alloc_args *args,
		       struct page **ret_page);
	void (*free)(struct arm_dma_free_args *args);
};

struct arm_dma_buffer {
	struct list_head list;
	void *virt;
	struct arm_dma_allocator *allocator;
};

static LIST_HEAD(arm_dma_bufs);
static DEFINE_SPINLOCK(arm_dma_bufs_lock);

static struct arm_dma_buffer *arm_dma_buffer_find(void *virt)
{
	struct arm_dma_buffer *buf, *found = NULL;
	unsigned long flags;

	spin_lock_irqsave(&arm_dma_bufs_lock, flags);
	list_for_each_entry(buf, &arm_dma_bufs, list) {
		if (buf->virt == virt) {
			list_del(&buf->list);
			found = buf;
			break;
		}
	}
	spin_unlock_irqrestore(&arm_dma_bufs_lock, flags);
	return found;
}

/*
 * The DMA API is built upon the notion of "buffer ownership".  A buffer
 * is either exclusively owned by the CPU (and therefore may be accessed
 * by it) or exclusively owned by the DMA device.  These helper functions
 * represent the transitions between these two ownership states.
 *
 * Note, however, that on later ARMs, this notion does not work due to
 * speculative prefetches.  We model our approach on the assumption that
 * the CPU does do speculative prefetches, which means we clean caches
 * before transfers and delay cache invalidation until transfer completion.
 *
 */

static void __dma_clear_buffer(struct page *page, size_t size, int coherent_flag)
{
	/*
	 * Ensure that the allocated pages are zeroed, and that any data
	 * lurking in the kernel direct-mapped region is invalidated.
	 */
	if (PageHighMem(page)) {
		phys_addr_t base = __pfn_to_phys(page_to_pfn(page));
		phys_addr_t end = base + size;
		while (size > 0) {
			void *ptr = kmap_atomic(page);
			memset(ptr, 0, PAGE_SIZE);
			if (coherent_flag != COHERENT)
				dmac_flush_range(ptr, ptr + PAGE_SIZE);
			kunmap_atomic(ptr);
			page++;
			size -= PAGE_SIZE;
		}
		if (coherent_flag != COHERENT)
			outer_flush_range(base, end);
	} else {
		void *ptr = page_address(page);
		memset(ptr, 0, size);
		if (coherent_flag != COHERENT) {
			dmac_flush_range(ptr, ptr + size);
			outer_flush_range(__pa(ptr), __pa(ptr) + size);
		}
	}
}

/*
 * Allocate a DMA buffer for 'dev' of size 'size' using the
 * specified gfp mask.  Note that 'size' must be page aligned.
 */
static struct page *__dma_alloc_buffer(struct device *dev, size_t size,
				       gfp_t gfp, int coherent_flag)
{
	unsigned long order = get_order(size);
	struct page *page, *p, *e;

	page = alloc_pages(gfp, order);
	if (!page)
		return NULL;

	/*
	 * Now split the huge page and free the excess pages
	 */
	split_page(page, order);
	for (p = page + (size >> PAGE_SHIFT), e = page + (1 << order); p < e; p++)
		__free_page(p);

	__dma_clear_buffer(page, size, coherent_flag);

	return page;
}

/*
 * Free a DMA buffer.  'size' must be page aligned.
 */
static void __dma_free_buffer(struct page *page, size_t size)
{
	struct page *e = page + (size >> PAGE_SHIFT);

	while (page < e) {
		__free_page(page);
		page++;
	}
}

static void *__alloc_from_contiguous(struct device *dev, size_t size,
				     pgprot_t prot, struct page **ret_page,
				     const void *caller, bool want_vaddr,
				     int coherent_flag, gfp_t gfp);

static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
				 pgprot_t prot, struct page **ret_page,
				 const void *caller, bool want_vaddr);

#define DEFAULT_DMA_COHERENT_POOL_SIZE	SZ_256K
static struct gen_pool *atomic_pool __ro_after_init;

static size_t atomic_pool_size __initdata = DEFAULT_DMA_COHERENT_POOL_SIZE;

static int __init early_coherent_pool(char *p)
{
	atomic_pool_size = memparse(p, &p);
	return 0;
}
early_param("coherent_pool", early_coherent_pool);

/*
 * Initialise the coherent pool for atomic allocations.
 */
static int __init atomic_pool_init(void)
{
	pgprot_t prot = pgprot_dmacoherent(PAGE_KERNEL);
	gfp_t gfp = GFP_KERNEL | GFP_DMA;
	struct page *page;
	void *ptr;

	atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
	if (!atomic_pool)
		goto out;
	/*
	 * The atomic pool is only used for non-coherent allocations
	 * so we must pass NORMAL for coherent_flag.
	 */
	if (dev_get_cma_area(NULL))
		ptr = __alloc_from_contiguous(NULL, atomic_pool_size, prot,
				      &page, atomic_pool_init, true, NORMAL,
				      GFP_KERNEL);
	else
		ptr = __alloc_remap_buffer(NULL, atomic_pool_size, gfp, prot,
					   &page, atomic_pool_init, true);
	if (ptr) {
		int ret;

		ret = gen_pool_add_virt(atomic_pool, (unsigned long)ptr,
					page_to_phys(page),
					atomic_pool_size, -1);
		if (ret)
			goto destroy_genpool;

		gen_pool_set_algo(atomic_pool,
				gen_pool_first_fit_order_align,
				NULL);
		pr_info("DMA: preallocated %zu KiB pool for atomic coherent allocations\n",
		       atomic_pool_size / 1024);
		return 0;
	}

destroy_genpool:
	gen_pool_destroy(atomic_pool);
	atomic_pool = NULL;
out:
	pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n",
	       atomic_pool_size / 1024);
	return -ENOMEM;
}
/*
 * CMA is activated by core_initcall, so we must be called after it.
 */
postcore_initcall(atomic_pool_init);

#ifdef CONFIG_CMA_AREAS
struct dma_contig_early_reserve {
	phys_addr_t base;
	unsigned long size;
};

static struct dma_contig_early_reserve dma_mmu_remap[MAX_CMA_AREAS] __initdata;

static int dma_mmu_remap_num __initdata;

void __init dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
{
	dma_mmu_remap[dma_mmu_remap_num].base = base;
	dma_mmu_remap[dma_mmu_remap_num].size = size;
	dma_mmu_remap_num++;
}

void __init dma_contiguous_remap(void)
{
	int i;
	for (i = 0; i < dma_mmu_remap_num; i++) {
		phys_addr_t start = dma_mmu_remap[i].base;
		phys_addr_t end = start + dma_mmu_remap[i].size;
		struct map_desc map;
		unsigned long addr;

		if (end > arm_lowmem_limit)
			end = arm_lowmem_limit;
		if (start >= end)
			continue;

		map.pfn = __phys_to_pfn(start);
		map.virtual = __phys_to_virt(start);
		map.length = end - start;
		map.type = MT_MEMORY_DMA_READY;

		/*
		 * Clear previous low-memory mapping to ensure that the
		 * TLB does not see any conflicting entries, then flush
		 * the TLB of the old entries before creating new mappings.
		 *
		 * This ensures that any speculatively loaded TLB entries
		 * (even though they may be rare) can not cause any problems,
		 * and ensures that this code is architecturally compliant.
		 */
		for (addr = __phys_to_virt(start); addr < __phys_to_virt(end);
		     addr += PMD_SIZE)
			pmd_clear(pmd_off_k(addr));

		flush_tlb_kernel_range(__phys_to_virt(start),
				       __phys_to_virt(end));

		iotable_init(&map, 1);
	}
}
#endif

static int __dma_update_pte(pte_t *pte, unsigned long addr, void *data)
{
	struct page *page = virt_to_page((void *)addr);
	pgprot_t prot = *(pgprot_t *)data;

	set_pte_ext(pte, mk_pte(page, prot), 0);
	return 0;
}

static void __dma_remap(struct page *page, size_t size, pgprot_t prot)
{
	unsigned long start = (unsigned long) page_address(page);
	unsigned end = start + size;

	apply_to_page_range(&init_mm, start, size, __dma_update_pte, &prot);
	flush_tlb_kernel_range(start, end);
}

static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
				 pgprot_t prot, struct page **ret_page,
				 const void *caller, bool want_vaddr)
{
	struct page *page;
	void *ptr = NULL;
	/*
	 * __alloc_remap_buffer is only called when the device is
	 * non-coherent
	 */
	page = __dma_alloc_buffer(dev, size, gfp, NORMAL);
	if (!page)
		return NULL;
	if (!want_vaddr)
		goto out;

	ptr = dma_common_contiguous_remap(page, size, prot, caller);
	if (!ptr) {
		__dma_free_buffer(page, size);
		return NULL;
	}

 out:
	*ret_page = page;
	return ptr;
}

static void *__alloc_from_pool(size_t size, struct page **ret_page)
{
	unsigned long val;
	void *ptr = NULL;

	if (!atomic_pool) {
		WARN(1, "coherent pool not initialised!\n");
		return NULL;
	}

	val = gen_pool_alloc(atomic_pool, size);
	if (val) {
		phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val);

		*ret_page = phys_to_page(phys);
		ptr = (void *)val;
	}

	return ptr;
}

static bool __in_atomic_pool(void *start, size_t size)
{
	return gen_pool_has_addr(atomic_pool, (unsigned long)start, size);
}

static int __free_from_pool(void *start, size_t size)
{
	if (!__in_atomic_pool(start, size))
		return 0;

	gen_pool_free(atomic_pool, (unsigned long)start, size);

	return 1;
}

static void *__alloc_from_contiguous(struct device *dev, size_t size,
				     pgprot_t prot, struct page **ret_page,
				     const void *caller, bool want_vaddr,
				     int coherent_flag, gfp_t gfp)
{
	unsigned long order = get_order(size);
	size_t count = size >> PAGE_SHIFT;
	struct page *page;
	void *ptr = NULL;

	page = dma_alloc_from_contiguous(dev, count, order, gfp & __GFP_NOWARN);
	if (!page)
		return NULL;

	__dma_clear_buffer(page, size, coherent_flag);

	if (!want_vaddr)
		goto out;

	if (PageHighMem(page)) {
		ptr = dma_common_contiguous_remap(page, size, prot, caller);
		if (!ptr) {
			dma_release_from_contiguous(dev, page, count);
			return NULL;
		}
	} else {
		__dma_remap(page, size, prot);
		ptr = page_address(page);
	}

 out:
	*ret_page = page;
	return ptr;
}

static void __free_from_contiguous(struct device *dev, struct page *page,
				   void *cpu_addr, size_t size, bool want_vaddr)
{
	if (want_vaddr) {
		if (PageHighMem(page))
			dma_common_free_remap(cpu_addr, size);
		else
			__dma_remap(page, size, PAGE_KERNEL);
	}
	dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
}

static inline pgprot_t __get_dma_pgprot(unsigned long attrs, pgprot_t prot)
{
	prot = (attrs & DMA_ATTR_WRITE_COMBINE) ?
			pgprot_writecombine(prot) :
			pgprot_dmacoherent(prot);
	return prot;
}

static void *__alloc_simple_buffer(struct device *dev, size_t size, gfp_t gfp,
				   struct page **ret_page)
{
	struct page *page;
	/* __alloc_simple_buffer is only called when the device is coherent */
	page = __dma_alloc_buffer(dev, size, gfp, COHERENT);
	if (!page)
		return NULL;

	*ret_page = page;
	return page_address(page);
}

static void *simple_allocator_alloc(struct arm_dma_alloc_args *args,
				    struct page **ret_page)
{
	return __alloc_simple_buffer(args->dev, args->size, args->gfp,
				     ret_page);
}

static void simple_allocator_free(struct arm_dma_free_args *args)
{
	__dma_free_buffer(args->page, args->size);
}

static struct arm_dma_allocator simple_allocator = {
	.alloc = simple_allocator_alloc,
	.free = simple_allocator_free,
};

static void *cma_allocator_alloc(struct arm_dma_alloc_args *args,
				 struct page **ret_page)
{
	return __alloc_from_contiguous(args->dev, args->size, args->prot,
				       ret_page, args->caller,
				       args->want_vaddr, args->coherent_flag,
				       args->gfp);
}

static void cma_allocator_free(struct arm_dma_free_args *args)
{
	__free_from_contiguous(args->dev, args->page, args->cpu_addr,
			       args->size, args->want_vaddr);
}

static struct arm_dma_allocator cma_allocator = {
	.alloc = cma_allocator_alloc,
	.free = cma_allocator_free,
};

static void *pool_allocator_alloc(struct arm_dma_alloc_args *args,
				  struct page **ret_page)
{
	return __alloc_from_pool(args->size, ret_page);
}

static void pool_allocator_free(struct arm_dma_free_args *args)
{
	__free_from_pool(args->cpu_addr, args->size);
}

static struct arm_dma_allocator pool_allocator = {
	.alloc = pool_allocator_alloc,
	.free = pool_allocator_free,
};

static void *remap_allocator_alloc(struct arm_dma_alloc_args *args,
				   struct page **ret_page)
{
	return __alloc_remap_buffer(args->dev, args->size, args->gfp,
				    args->prot, ret_page, args->caller,
				    args->want_vaddr);
}

static void remap_allocator_free(struct arm_dma_free_args *args)
{
	if (args->want_vaddr)
		dma_common_free_remap(args->cpu_addr, args->size);

	__dma_free_buffer(args->page, args->size);
}

static struct arm_dma_allocator remap_allocator = {
	.alloc = remap_allocator_alloc,
	.free = remap_allocator_free,
};

static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
			 gfp_t gfp, pgprot_t prot, bool is_coherent,
			 unsigned long attrs, const void *caller)
{
	u64 mask = min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
	struct page *page = NULL;
	void *addr;
	bool allowblock, cma;
	struct arm_dma_buffer *buf;
	struct arm_dma_alloc_args args = {
		.dev = dev,
		.size = PAGE_ALIGN(size),
		.gfp = gfp,
		.prot = prot,
		.caller = caller,
		.want_vaddr = ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0),
		.coherent_flag = is_coherent ? COHERENT : NORMAL,
	};

#ifdef CONFIG_DMA_API_DEBUG
	u64 limit = (mask + 1) & ~mask;
	if (limit && size >= limit) {
		dev_warn(dev, "coherent allocation too big (requested %#x mask %#llx)\n",
			size, mask);
		return NULL;
	}
#endif

	buf = kzalloc(sizeof(*buf),
		      gfp & ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM));
	if (!buf)
		return NULL;

	if (mask < 0xffffffffULL)
		gfp |= GFP_DMA;

	args.gfp = gfp;

	*handle = DMA_MAPPING_ERROR;
	allowblock = gfpflags_allow_blocking(gfp);
	cma = allowblock ? dev_get_cma_area(dev) : NULL;

	if (cma)
		buf->allocator = &cma_allocator;
	else if (is_coherent)
		buf->allocator = &simple_allocator;
	else if (allowblock)
		buf->allocator = &remap_allocator;
	else
		buf->allocator = &pool_allocator;

	addr = buf->allocator->alloc(&args, &page);

	if (page) {
		unsigned long flags;

		*handle = phys_to_dma(dev, page_to_phys(page));
		buf->virt = args.want_vaddr ? addr : page;

		spin_lock_irqsave(&arm_dma_bufs_lock, flags);
		list_add(&buf->list, &arm_dma_bufs);
		spin_unlock_irqrestore(&arm_dma_bufs_lock, flags);
	} else {
		kfree(buf);
	}

	return args.want_vaddr ? addr : page;
}

/*
 * Free a buffer as defined by the above mapping.
 */
static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
			   dma_addr_t handle, unsigned long attrs,
			   bool is_coherent)
{
	struct page *page = phys_to_page(dma_to_phys(dev, handle));
	struct arm_dma_buffer *buf;
	struct arm_dma_free_args args = {
		.dev = dev,
		.size = PAGE_ALIGN(size),
		.cpu_addr = cpu_addr,
		.page = page,
		.want_vaddr = ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0),
	};

	buf = arm_dma_buffer_find(cpu_addr);
	if (WARN(!buf, "Freeing invalid buffer %p\n", cpu_addr))
		return;

	buf->allocator->free(&args);
	kfree(buf);
}

static void dma_cache_maint_page(struct page *page, unsigned long offset,
	size_t size, enum dma_data_direction dir,
	void (*op)(const void *, size_t, int))
{
	unsigned long pfn;
	size_t left = size;

	pfn = page_to_pfn(page) + offset / PAGE_SIZE;
	offset %= PAGE_SIZE;

	/*
	 * A single sg entry may refer to multiple physically contiguous
	 * pages.  But we still need to process highmem pages individually.
	 * If highmem is not configured then the bulk of this loop gets
	 * optimized out.
	 */
	do {
		size_t len = left;
		void *vaddr;

		page = pfn_to_page(pfn);

		if (PageHighMem(page)) {
			if (len + offset > PAGE_SIZE)
				len = PAGE_SIZE - offset;

			if (cache_is_vipt_nonaliasing()) {
				vaddr = kmap_atomic(page);
				op(vaddr + offset, len, dir);
				kunmap_atomic(vaddr);
			} else {
				vaddr = kmap_high_get(page);
				if (vaddr) {
					op(vaddr + offset, len, dir);
					kunmap_high(page);
				}
			}
		} else {
			vaddr = page_address(page) + offset;
			op(vaddr, len, dir);
		}
		offset = 0;
		pfn++;
		left -= len;
	} while (left);
}

/*
 * Make an area consistent for devices.
 * Note: Drivers should NOT use this function directly.
 * Use the driver DMA support - see dma-mapping.h (dma_sync_*)
 */
static void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
	size_t size, enum dma_data_direction dir)
{
	phys_addr_t paddr;

	dma_cache_maint_page(page, off, size, dir, dmac_map_area);

	paddr = page_to_phys(page) + off;
	if (dir == DMA_FROM_DEVICE) {
		outer_inv_range(paddr, paddr + size);
	} else {
		outer_clean_range(paddr, paddr + size);
	}
	/* FIXME: non-speculating: flush on bidirectional mappings? */
}

static void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
	size_t size, enum dma_data_direction dir)
{
	phys_addr_t paddr = page_to_phys(page) + off;

	/* FIXME: non-speculating: not required */
	/* in any case, don't bother invalidating if DMA to device */
	if (dir != DMA_TO_DEVICE) {
		outer_inv_range(paddr, paddr + size);

		dma_cache_maint_page(page, off, size, dir, dmac_unmap_area);
	}

	/*
	 * Mark the D-cache clean for these pages to avoid extra flushing.
	 */
	if (dir != DMA_TO_DEVICE && size >= PAGE_SIZE) {
		unsigned long pfn;
		size_t left = size;

		pfn = page_to_pfn(page) + off / PAGE_SIZE;
		off %= PAGE_SIZE;
		if (off) {
			pfn++;
			left -= PAGE_SIZE - off;
		}
		while (left >= PAGE_SIZE) {
			page = pfn_to_page(pfn++);
			set_bit(PG_dcache_clean, &page->flags);
			left -= PAGE_SIZE;
		}
	}
}

#ifdef CONFIG_ARM_DMA_USE_IOMMU

static int __dma_info_to_prot(enum dma_data_direction dir, unsigned long attrs)
{
	int prot = 0;

	if (attrs & DMA_ATTR_PRIVILEGED)
		prot |= IOMMU_PRIV;

	switch (dir) {
	case DMA_BIDIRECTIONAL:
		return prot | IOMMU_READ | IOMMU_WRITE;
	case DMA_TO_DEVICE:
		return prot | IOMMU_READ;
	case DMA_FROM_DEVICE:
		return prot | IOMMU_WRITE;
	default:
		return prot;
	}
}

/* IOMMU */

static int extend_iommu_mapping(struct dma_iommu_mapping *mapping);

static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
				      size_t size)
{
	unsigned int order = get_order(size);
	unsigned int align = 0;
	unsigned int count, start;
	size_t mapping_size = mapping->bits << PAGE_SHIFT;
	unsigned long flags;
	dma_addr_t iova;
	int i;

	if (order > CONFIG_ARM_DMA_IOMMU_ALIGNMENT)
		order = CONFIG_ARM_DMA_IOMMU_ALIGNMENT;

	count = PAGE_ALIGN(size) >> PAGE_SHIFT;
	align = (1 << order) - 1;

	spin_lock_irqsave(&mapping->lock, flags);
	for (i = 0; i < mapping->nr_bitmaps; i++) {
		start = bitmap_find_next_zero_area(mapping->bitmaps[i],
				mapping->bits, 0, count, align);

		if (start > mapping->bits)
			continue;

		bitmap_set(mapping->bitmaps[i], start, count);
		break;
	}

	/*
	 * No unused range found. Try to extend the existing mapping
	 * and perform a second attempt to reserve an IO virtual
	 * address range of size bytes.
	 */
	if (i == mapping->nr_bitmaps) {
		if (extend_iommu_mapping(mapping)) {
			spin_unlock_irqrestore(&mapping->lock, flags);
			return DMA_MAPPING_ERROR;
		}

		start = bitmap_find_next_zero_area(mapping->bitmaps[i],
				mapping->bits, 0, count, align);

		if (start > mapping->bits) {
			spin_unlock_irqrestore(&mapping->lock, flags);
			return DMA_MAPPING_ERROR;
		}

		bitmap_set(mapping->bitmaps[i], start, count);
	}
	spin_unlock_irqrestore(&mapping->lock, flags);

	iova = mapping->base + (mapping_size * i);
	iova += start << PAGE_SHIFT;

	return iova;
}

static inline void __free_iova(struct dma_iommu_mapping *mapping,
			       dma_addr_t addr, size_t size)
{
	unsigned int start, count;
	size_t mapping_size = mapping->bits << PAGE_SHIFT;
	unsigned long flags;
	dma_addr_t bitmap_base;
	u32 bitmap_index;

	if (!size)
		return;

	bitmap_index = (u32) (addr - mapping->base) / (u32) mapping_size;
	BUG_ON(addr < mapping->base || bitmap_index > mapping->extensions);

	bitmap_base = mapping->base + mapping_size * bitmap_index;

	start = (addr - bitmap_base) >>	PAGE_SHIFT;

	if (addr + size > bitmap_base + mapping_size) {
		/*
		 * The address range to be freed reaches into the iova
		 * range of the next bitmap. This should not happen as
		 * we don't allow this in __alloc_iova (at the
		 * moment).
		 */
		BUG();
	} else
		count = size >> PAGE_SHIFT;

	spin_lock_irqsave(&mapping->lock, flags);
	bitmap_clear(mapping->bitmaps[bitmap_index], start, count);
	spin_unlock_irqrestore(&mapping->lock, flags);
}

/* We'll try 2M, 1M, 64K, and finally 4K; array must end with 0! */
static const int iommu_order_array[] = { 9, 8, 4, 0 };

static struct page **__iommu_alloc_buffer(struct device *dev, size_t size,
					  gfp_t gfp, unsigned long attrs,
					  int coherent_flag)
{
	struct page **pages;
	int count = size >> PAGE_SHIFT;
	int array_size = count * sizeof(struct page *);
	int i = 0;
	int order_idx = 0;

	if (array_size <= PAGE_SIZE)
		pages = kzalloc(array_size, GFP_KERNEL);
	else
		pages = vzalloc(array_size);
	if (!pages)
		return NULL;

	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS)
	{
		unsigned long order = get_order(size);
		struct page *page;

		page = dma_alloc_from_contiguous(dev, count, order,
						 gfp & __GFP_NOWARN);
		if (!page)
			goto error;

		__dma_clear_buffer(page, size, coherent_flag);

		for (i = 0; i < count; i++)
			pages[i] = page + i;

		return pages;
	}

	/* Go straight to 4K chunks if caller says it's OK. */
	if (attrs & DMA_ATTR_ALLOC_SINGLE_PAGES)
		order_idx = ARRAY_SIZE(iommu_order_array) - 1;

	/*
	 * IOMMU can map any pages, so himem can also be used here
	 */
	gfp |= __GFP_NOWARN | __GFP_HIGHMEM;

	while (count) {
		int j, order;

		order = iommu_order_array[order_idx];

		/* Drop down when we get small */
		if (__fls(count) < order) {
			order_idx++;
			continue;
		}

		if (order) {
			/* See if it's easy to allocate a high-order chunk */
			pages[i] = alloc_pages(gfp | __GFP_NORETRY, order);

			/* Go down a notch at first sign of pressure */
			if (!pages[i]) {
				order_idx++;
				continue;
			}
		} else {
			pages[i] = alloc_pages(gfp, 0);
			if (!pages[i])
				goto error;
		}

		if (order) {
			split_page(pages[i], order);
			j = 1 << order;
			while (--j)
				pages[i + j] = pages[i] + j;
		}

		__dma_clear_buffer(pages[i], PAGE_SIZE << order, coherent_flag);
		i += 1 << order;
		count -= 1 << order;
	}

	return pages;
error:
	while (i--)
		if (pages[i])
			__free_pages(pages[i], 0);
	kvfree(pages);
	return NULL;
}

static int __iommu_free_buffer(struct device *dev, struct page **pages,
			       size_t size, unsigned long attrs)
{
	int count = size >> PAGE_SHIFT;
	int i;

	if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
		dma_release_from_contiguous(dev, pages[0], count);
	} else {
		for (i = 0; i < count; i++)
			if (pages[i])
				__free_pages(pages[i], 0);
	}

	kvfree(pages);
	return 0;
}

/*
 * Create a mapping in device IO address space for specified pages
 */
static dma_addr_t
__iommu_create_mapping(struct device *dev, struct page **pages, size_t size,
		       unsigned long attrs)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
	dma_addr_t dma_addr, iova;
	int i;

	dma_addr = __alloc_iova(mapping, size);
	if (dma_addr == DMA_MAPPING_ERROR)
		return dma_addr;

	iova = dma_addr;
	for (i = 0; i < count; ) {
		int ret;

		unsigned int next_pfn = page_to_pfn(pages[i]) + 1;
		phys_addr_t phys = page_to_phys(pages[i]);
		unsigned int len, j;

		for (j = i + 1; j < count; j++, next_pfn++)
			if (page_to_pfn(pages[j]) != next_pfn)
				break;

		len = (j - i) << PAGE_SHIFT;
		ret = iommu_map(mapping->domain, iova, phys, len,
				__dma_info_to_prot(DMA_BIDIRECTIONAL, attrs),
				GFP_KERNEL);
		if (ret < 0)
			goto fail;
		iova += len;
		i = j;
	}
	return dma_addr;
fail:
	iommu_unmap(mapping->domain, dma_addr, iova-dma_addr);
	__free_iova(mapping, dma_addr, size);
	return DMA_MAPPING_ERROR;
}

static int __iommu_remove_mapping(struct device *dev, dma_addr_t iova, size_t size)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);

	/*
	 * add optional in-page offset from iova to size and align
	 * result to page size
	 */
	size = PAGE_ALIGN((iova & ~PAGE_MASK) + size);
	iova &= PAGE_MASK;

	iommu_unmap(mapping->domain, iova, size);
	__free_iova(mapping, iova, size);
	return 0;
}

static struct page **__atomic_get_pages(void *addr)
{
	struct page *page;
	phys_addr_t phys;

	phys = gen_pool_virt_to_phys(atomic_pool, (unsigned long)addr);
	page = phys_to_page(phys);

	return (struct page **)page;
}

static struct page **__iommu_get_pages(void *cpu_addr, unsigned long attrs)
{
	if (__in_atomic_pool(cpu_addr, PAGE_SIZE))
		return __atomic_get_pages(cpu_addr);

	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
		return cpu_addr;

	return dma_common_find_pages(cpu_addr);
}

static void *__iommu_alloc_simple(struct device *dev, size_t size, gfp_t gfp,
				  dma_addr_t *handle, int coherent_flag,
				  unsigned long attrs)
{
	struct page *page;
	void *addr;

	if (coherent_flag  == COHERENT)
		addr = __alloc_simple_buffer(dev, size, gfp, &page);
	else
		addr = __alloc_from_pool(size, &page);
	if (!addr)
		return NULL;

	*handle = __iommu_create_mapping(dev, &page, size, attrs);
	if (*handle == DMA_MAPPING_ERROR)
		goto err_mapping;

	return addr;

err_mapping:
	__free_from_pool(addr, size);
	return NULL;
}

static void __iommu_free_atomic(struct device *dev, void *cpu_addr,
			dma_addr_t handle, size_t size, int coherent_flag)
{
	__iommu_remove_mapping(dev, handle, size);
	if (coherent_flag == COHERENT)
		__dma_free_buffer(virt_to_page(cpu_addr), size);
	else
		__free_from_pool(cpu_addr, size);
}

static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
	    dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
{
	pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL);
	struct page **pages;
	void *addr = NULL;
	int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;

	*handle = DMA_MAPPING_ERROR;
	size = PAGE_ALIGN(size);

	if (coherent_flag  == COHERENT || !gfpflags_allow_blocking(gfp))
		return __iommu_alloc_simple(dev, size, gfp, handle,
					    coherent_flag, attrs);

	pages = __iommu_alloc_buffer(dev, size, gfp, attrs, coherent_flag);
	if (!pages)
		return NULL;

	*handle = __iommu_create_mapping(dev, pages, size, attrs);
	if (*handle == DMA_MAPPING_ERROR)
		goto err_buffer;

	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
		return pages;

	addr = dma_common_pages_remap(pages, size, prot,
				   __builtin_return_address(0));
	if (!addr)
		goto err_mapping;

	return addr;

err_mapping:
	__iommu_remove_mapping(dev, *handle, size);
err_buffer:
	__iommu_free_buffer(dev, pages, size, attrs);
	return NULL;
}

static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
		    void *cpu_addr, dma_addr_t dma_addr, size_t size,
		    unsigned long attrs)
{
	struct page **pages = __iommu_get_pages(cpu_addr, attrs);
	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
	int err;

	if (!pages)
		return -ENXIO;

	if (vma->vm_pgoff >= nr_pages)
		return -ENXIO;

	if (!dev->dma_coherent)
		vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);

	err = vm_map_pages(vma, pages, nr_pages);
	if (err)
		pr_err("Remapping memory failed: %d\n", err);

	return err;
}

/*
 * free a page as defined by the above mapping.
 * Must not be called with IRQs disabled.
 */
static void arm_iommu_free_attrs(struct device *dev, size_t size, void *cpu_addr,
	dma_addr_t handle, unsigned long attrs)
{
	int coherent_flag = dev->dma_coherent ? COHERENT : NORMAL;
	struct page **pages;
	size = PAGE_ALIGN(size);

	if (coherent_flag == COHERENT || __in_atomic_pool(cpu_addr, size)) {
		__iommu_free_atomic(dev, cpu_addr, handle, size, coherent_flag);
		return;
	}

	pages = __iommu_get_pages(cpu_addr, attrs);
	if (!pages) {
		WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
		return;
	}

	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
		dma_common_free_remap(cpu_addr, size);

	__iommu_remove_mapping(dev, handle, size);
	__iommu_free_buffer(dev, pages, size, attrs);
}

static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt,
				 void *cpu_addr, dma_addr_t dma_addr,
				 size_t size, unsigned long attrs)
{
	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
	struct page **pages = __iommu_get_pages(cpu_addr, attrs);

	if (!pages)
		return -ENXIO;

	return sg_alloc_table_from_pages(sgt, pages, count, 0, size,
					 GFP_KERNEL);
}

/*
 * Map a part of the scatter-gather list into contiguous io address space
 */
static int __map_sg_chunk(struct device *dev, struct scatterlist *sg,
			  size_t size, dma_addr_t *handle,
			  enum dma_data_direction dir, unsigned long attrs)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
	dma_addr_t iova, iova_base;
	int ret = 0;
	unsigned int count;
	struct scatterlist *s;
	int prot;

	size = PAGE_ALIGN(size);
	*handle = DMA_MAPPING_ERROR;

	iova_base = iova = __alloc_iova(mapping, size);
	if (iova == DMA_MAPPING_ERROR)
		return -ENOMEM;

	for (count = 0, s = sg; count < (size >> PAGE_SHIFT); s = sg_next(s)) {
		phys_addr_t phys = page_to_phys(sg_page(s));
		unsigned int len = PAGE_ALIGN(s->offset + s->length);

		if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
			__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);

		prot = __dma_info_to_prot(dir, attrs);

		ret = iommu_map(mapping->domain, iova, phys, len, prot,
				GFP_KERNEL);
		if (ret < 0)
			goto fail;
		count += len >> PAGE_SHIFT;
		iova += len;
	}
	*handle = iova_base;

	return 0;
fail:
	iommu_unmap(mapping->domain, iova_base, count * PAGE_SIZE);
	__free_iova(mapping, iova_base, size);
	return ret;
}

/**
 * arm_iommu_map_sg - map a set of SG buffers for streaming mode DMA
 * @dev: valid struct device pointer
 * @sg: list of buffers
 * @nents: number of buffers to map
 * @dir: DMA transfer direction
 *
 * Map a set of buffers described by scatterlist in streaming mode for DMA.
 * The scatter gather list elements are merged together (if possible) and
 * tagged with the appropriate dma address and length. They are obtained via
 * sg_dma_{address,length}.
 */
static int arm_iommu_map_sg(struct device *dev, struct scatterlist *sg,
		int nents, enum dma_data_direction dir, unsigned long attrs)
{
	struct scatterlist *s = sg, *dma = sg, *start = sg;
	int i, count = 0, ret;
	unsigned int offset = s->offset;
	unsigned int size = s->offset + s->length;
	unsigned int max = dma_get_max_seg_size(dev);

	for (i = 1; i < nents; i++) {
		s = sg_next(s);

		s->dma_length = 0;

		if (s->offset || (size & ~PAGE_MASK) || size + s->length > max) {
			ret = __map_sg_chunk(dev, start, size,
					     &dma->dma_address, dir, attrs);
			if (ret < 0)
				goto bad_mapping;

			dma->dma_address += offset;
			dma->dma_length = size - offset;

			size = offset = s->offset;
			start = s;
			dma = sg_next(dma);
			count += 1;
		}
		size += s->length;
	}
	ret = __map_sg_chunk(dev, start, size, &dma->dma_address, dir, attrs);
	if (ret < 0)
		goto bad_mapping;

	dma->dma_address += offset;
	dma->dma_length = size - offset;

	return count+1;

bad_mapping:
	for_each_sg(sg, s, count, i)
		__iommu_remove_mapping(dev, sg_dma_address(s), sg_dma_len(s));
	if (ret == -ENOMEM)
		return ret;
	return -EINVAL;
}

/**
 * arm_iommu_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg
 * @dev: valid struct device pointer
 * @sg: list of buffers
 * @nents: number of buffers to unmap (same as was passed to dma_map_sg)
 * @dir: DMA transfer direction (same as was passed to dma_map_sg)
 *
 * Unmap a set of streaming mode DMA translations.  Again, CPU access
 * rules concerning calls here are the same as for dma_unmap_single().
 */
static void arm_iommu_unmap_sg(struct device *dev,
			       struct scatterlist *sg, int nents,
			       enum dma_data_direction dir,
			       unsigned long attrs)
{
	struct scatterlist *s;
	int i;

	for_each_sg(sg, s, nents, i) {
		if (sg_dma_len(s))
			__iommu_remove_mapping(dev, sg_dma_address(s),
					       sg_dma_len(s));
		if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
			__dma_page_dev_to_cpu(sg_page(s), s->offset,
					      s->length, dir);
	}
}

/**
 * arm_iommu_sync_sg_for_cpu
 * @dev: valid struct device pointer
 * @sg: list of buffers
 * @nents: number of buffers to map (returned from dma_map_sg)
 * @dir: DMA transfer direction (same as was passed to dma_map_sg)
 */
static void arm_iommu_sync_sg_for_cpu(struct device *dev,
			struct scatterlist *sg,
			int nents, enum dma_data_direction dir)
{
	struct scatterlist *s;
	int i;

	if (dev->dma_coherent)
		return;

	for_each_sg(sg, s, nents, i)
		__dma_page_dev_to_cpu(sg_page(s), s->offset, s->length, dir);

}

/**
 * arm_iommu_sync_sg_for_device
 * @dev: valid struct device pointer
 * @sg: list of buffers
 * @nents: number of buffers to map (returned from dma_map_sg)
 * @dir: DMA transfer direction (same as was passed to dma_map_sg)
 */
static void arm_iommu_sync_sg_for_device(struct device *dev,
			struct scatterlist *sg,
			int nents, enum dma_data_direction dir)
{
	struct scatterlist *s;
	int i;

	if (dev->dma_coherent)
		return;

	for_each_sg(sg, s, nents, i)
		__dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
}

/**
 * arm_iommu_map_page
 * @dev: valid struct device pointer
 * @page: page that buffer resides in
 * @offset: offset into page for start of buffer
 * @size: size of buffer to map
 * @dir: DMA transfer direction
 *
 * IOMMU aware version of arm_dma_map_page()
 */
static dma_addr_t arm_iommu_map_page(struct device *dev, struct page *page,
	     unsigned long offset, size_t size, enum dma_data_direction dir,
	     unsigned long attrs)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
	dma_addr_t dma_addr;
	int ret, prot, len = PAGE_ALIGN(size + offset);

	if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
		__dma_page_cpu_to_dev(page, offset, size, dir);

	dma_addr = __alloc_iova(mapping, len);
	if (dma_addr == DMA_MAPPING_ERROR)
		return dma_addr;

	prot = __dma_info_to_prot(dir, attrs);

	ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len,
			prot, GFP_KERNEL);
	if (ret < 0)
		goto fail;

	return dma_addr + offset;
fail:
	__free_iova(mapping, dma_addr, len);
	return DMA_MAPPING_ERROR;
}

/**
 * arm_iommu_unmap_page
 * @dev: valid struct device pointer
 * @handle: DMA address of buffer
 * @size: size of buffer (same as passed to dma_map_page)
 * @dir: DMA transfer direction (same as passed to dma_map_page)
 *
 * IOMMU aware version of arm_dma_unmap_page()
 */
static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle,
		size_t size, enum dma_data_direction dir, unsigned long attrs)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
	dma_addr_t iova = handle & PAGE_MASK;
	struct page *page;
	int offset = handle & ~PAGE_MASK;
	int len = PAGE_ALIGN(size + offset);

	if (!iova)
		return;

	if (!dev->dma_coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
		page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
		__dma_page_dev_to_cpu(page, offset, size, dir);
	}

	iommu_unmap(mapping->domain, iova, len);
	__free_iova(mapping, iova, len);
}

/**
 * arm_iommu_map_resource - map a device resource for DMA
 * @dev: valid struct device pointer
 * @phys_addr: physical address of resource
 * @size: size of resource to map
 * @dir: DMA transfer direction
 */
static dma_addr_t arm_iommu_map_resource(struct device *dev,
		phys_addr_t phys_addr, size_t size,
		enum dma_data_direction dir, unsigned long attrs)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
	dma_addr_t dma_addr;
	int ret, prot;
	phys_addr_t addr = phys_addr & PAGE_MASK;
	unsigned int offset = phys_addr & ~PAGE_MASK;
	size_t len = PAGE_ALIGN(size + offset);

	dma_addr = __alloc_iova(mapping, len);
	if (dma_addr == DMA_MAPPING_ERROR)
		return dma_addr;

	prot = __dma_info_to_prot(dir, attrs) | IOMMU_MMIO;

	ret = iommu_map(mapping->domain, dma_addr, addr, len, prot, GFP_KERNEL);
	if (ret < 0)
		goto fail;

	return dma_addr + offset;
fail:
	__free_iova(mapping, dma_addr, len);
	return DMA_MAPPING_ERROR;
}

/**
 * arm_iommu_unmap_resource - unmap a device DMA resource
 * @dev: valid struct device pointer
 * @dma_handle: DMA address to resource
 * @size: size of resource to map
 * @dir: DMA transfer direction
 */
static void arm_iommu_unmap_resource(struct device *dev, dma_addr_t dma_handle,
		size_t size, enum dma_data_direction dir,
		unsigned long attrs)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
	dma_addr_t iova = dma_handle & PAGE_MASK;
	unsigned int offset = dma_handle & ~PAGE_MASK;
	size_t len = PAGE_ALIGN(size + offset);

	if (!iova)
		return;

	iommu_unmap(mapping->domain, iova, len);
	__free_iova(mapping, iova, len);
}

static void arm_iommu_sync_single_for_cpu(struct device *dev,
		dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
	dma_addr_t iova = handle & PAGE_MASK;
	struct page *page;
	unsigned int offset = handle & ~PAGE_MASK;

	if (dev->dma_coherent || !iova)
		return;

	page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
	__dma_page_dev_to_cpu(page, offset, size, dir);
}

static void arm_iommu_sync_single_for_device(struct device *dev,
		dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
	dma_addr_t iova = handle & PAGE_MASK;
	struct page *page;
	unsigned int offset = handle & ~PAGE_MASK;

	if (dev->dma_coherent || !iova)
		return;

	page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
	__dma_page_cpu_to_dev(page, offset, size, dir);
}

static const struct dma_map_ops iommu_ops = {
	.alloc		= arm_iommu_alloc_attrs,
	.free		= arm_iommu_free_attrs,
	.mmap		= arm_iommu_mmap_attrs,
	.get_sgtable	= arm_iommu_get_sgtable,

	.map_page		= arm_iommu_map_page,
	.unmap_page		= arm_iommu_unmap_page,
	.sync_single_for_cpu	= arm_iommu_sync_single_for_cpu,
	.sync_single_for_device	= arm_iommu_sync_single_for_device,

	.map_sg			= arm_iommu_map_sg,
	.unmap_sg		= arm_iommu_unmap_sg,
	.sync_sg_for_cpu	= arm_iommu_sync_sg_for_cpu,
	.sync_sg_for_device	= arm_iommu_sync_sg_for_device,

	.map_resource		= arm_iommu_map_resource,
	.unmap_resource		= arm_iommu_unmap_resource,
};

/**
 * arm_iommu_create_mapping
 * @bus: pointer to the bus holding the client device (for IOMMU calls)
 * @base: start address of the valid IO address space
 * @size: maximum size of the valid IO address space
 *
 * Creates a mapping structure which holds information about used/unused
 * IO address ranges, which is required to perform memory allocation and
 * mapping with IOMMU aware functions.
 *
 * The client device need to be attached to the mapping with
 * arm_iommu_attach_device function.
 */
struct dma_iommu_mapping *
arm_iommu_create_mapping(const struct bus_type *bus, dma_addr_t base, u64 size)
{
	unsigned int bits = size >> PAGE_SHIFT;
	unsigned int bitmap_size = BITS_TO_LONGS(bits) * sizeof(long);
	struct dma_iommu_mapping *mapping;
	int extensions = 1;
	int err = -ENOMEM;

	/* currently only 32-bit DMA address space is supported */
	if (size > DMA_BIT_MASK(32) + 1)
		return ERR_PTR(-ERANGE);

	if (!bitmap_size)
		return ERR_PTR(-EINVAL);

	if (bitmap_size > PAGE_SIZE) {
		extensions = bitmap_size / PAGE_SIZE;
		bitmap_size = PAGE_SIZE;
	}

	mapping = kzalloc(sizeof(struct dma_iommu_mapping), GFP_KERNEL);
	if (!mapping)
		goto err;

	mapping->bitmap_size = bitmap_size;
	mapping->bitmaps = kcalloc(extensions, sizeof(unsigned long *),
				   GFP_KERNEL);
	if (!mapping->bitmaps)
		goto err2;

	mapping->bitmaps[0] = kzalloc(bitmap_size, GFP_KERNEL);
	if (!mapping->bitmaps[0])
		goto err3;

	mapping->nr_bitmaps = 1;
	mapping->extensions = extensions;
	mapping->base = base;
	mapping->bits = BITS_PER_BYTE * bitmap_size;

	spin_lock_init(&mapping->lock);

	mapping->domain = iommu_domain_alloc(bus);
	if (!mapping->domain)
		goto err4;

	kref_init(&mapping->kref);
	return mapping;
err4:
	kfree(mapping->bitmaps[0]);
err3:
	kfree(mapping->bitmaps);
err2:
	kfree(mapping);
err:
	return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(arm_iommu_create_mapping);

static void release_iommu_mapping(struct kref *kref)
{
	int i;
	struct dma_iommu_mapping *mapping =
		container_of(kref, struct dma_iommu_mapping, kref);

	iommu_domain_free(mapping->domain);
	for (i = 0; i < mapping->nr_bitmaps; i++)
		kfree(mapping->bitmaps[i]);
	kfree(mapping->bitmaps);
	kfree(mapping);
}

static int extend_iommu_mapping(struct dma_iommu_mapping *mapping)
{
	int next_bitmap;

	if (mapping->nr_bitmaps >= mapping->extensions)
		return -EINVAL;

	next_bitmap = mapping->nr_bitmaps;
	mapping->bitmaps[next_bitmap] = kzalloc(mapping->bitmap_size,
						GFP_ATOMIC);
	if (!mapping->bitmaps[next_bitmap])
		return -ENOMEM;

	mapping->nr_bitmaps++;

	return 0;
}

void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping)
{
	if (mapping)
		kref_put(&mapping->kref, release_iommu_mapping);
}
EXPORT_SYMBOL_GPL(arm_iommu_release_mapping);

static int __arm_iommu_attach_device(struct device *dev,
				     struct dma_iommu_mapping *mapping)
{
	int err;

	err = iommu_attach_device(mapping->domain, dev);
	if (err)
		return err;

	kref_get(&mapping->kref);
	to_dma_iommu_mapping(dev) = mapping;

	pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev));
	return 0;
}

/**
 * arm_iommu_attach_device
 * @dev: valid struct device pointer
 * @mapping: io address space mapping structure (returned from
 *	arm_iommu_create_mapping)
 *
 * Attaches specified io address space mapping to the provided device.
 * This replaces the dma operations (dma_map_ops pointer) with the
 * IOMMU aware version.
 *
 * More than one client might be attached to the same io address space
 * mapping.
 */
int arm_iommu_attach_device(struct device *dev,
			    struct dma_iommu_mapping *mapping)
{
	int err;

	err = __arm_iommu_attach_device(dev, mapping);
	if (err)
		return err;

	set_dma_ops(dev, &iommu_ops);
	return 0;
}
EXPORT_SYMBOL_GPL(arm_iommu_attach_device);

/**
 * arm_iommu_detach_device
 * @dev: valid struct device pointer
 *
 * Detaches the provided device from a previously attached map.
 * This overwrites the dma_ops pointer with appropriate non-IOMMU ops.
 */
void arm_iommu_detach_device(struct device *dev)
{
	struct dma_iommu_mapping *mapping;

	mapping = to_dma_iommu_mapping(dev);
	if (!mapping) {
		dev_warn(dev, "Not attached\n");
		return;
	}

	iommu_detach_device(mapping->domain, dev);
	kref_put(&mapping->kref, release_iommu_mapping);
	to_dma_iommu_mapping(dev) = NULL;
	set_dma_ops(dev, NULL);

	pr_debug("Detached IOMMU controller from %s device.\n", dev_name(dev));
}
EXPORT_SYMBOL_GPL(arm_iommu_detach_device);

static void arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
				    const struct iommu_ops *iommu, bool coherent)
{
	struct dma_iommu_mapping *mapping;

	mapping = arm_iommu_create_mapping(dev->bus, dma_base, size);
	if (IS_ERR(mapping)) {
		pr_warn("Failed to create %llu-byte IOMMU mapping for device %s\n",
				size, dev_name(dev));
		return;
	}

	if (__arm_iommu_attach_device(dev, mapping)) {
		pr_warn("Failed to attached device %s to IOMMU_mapping\n",
				dev_name(dev));
		arm_iommu_release_mapping(mapping);
		return;
	}

	set_dma_ops(dev, &iommu_ops);
}

static void arm_teardown_iommu_dma_ops(struct device *dev)
{
	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);

	if (!mapping)
		return;

	arm_iommu_detach_device(dev);
	arm_iommu_release_mapping(mapping);
}

#else

static void arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
				    const struct iommu_ops *iommu, bool coherent)
{
}

static void arm_teardown_iommu_dma_ops(struct device *dev) { }

#endif	/* CONFIG_ARM_DMA_USE_IOMMU */

void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
			const struct iommu_ops *iommu, bool coherent)
{
	/*
	 * Due to legacy code that sets the ->dma_coherent flag from a bus
	 * notifier we can't just assign coherent to the ->dma_coherent flag
	 * here, but instead have to make sure we only set but never clear it
	 * for now.
	 */
	if (coherent)
		dev->dma_coherent = true;

	/*
	 * Don't override the dma_ops if they have already been set. Ideally
	 * this should be the only location where dma_ops are set, remove this
	 * check when all other callers of set_dma_ops will have disappeared.
	 */
	if (dev->dma_ops)
		return;

	if (iommu)
		arm_setup_iommu_dma_ops(dev, dma_base, size, iommu, coherent);

	xen_setup_dma_ops(dev);
	dev->archdata.dma_ops_setup = true;
}

void arch_teardown_dma_ops(struct device *dev)
{
	if (!dev->archdata.dma_ops_setup)
		return;

	arm_teardown_iommu_dma_ops(dev);
	/* Let arch_setup_dma_ops() start again from scratch upon re-probe */
	set_dma_ops(dev, NULL);
}

void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
		enum dma_data_direction dir)
{
	__dma_page_cpu_to_dev(phys_to_page(paddr), paddr & (PAGE_SIZE - 1),
			      size, dir);
}

void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
		enum dma_data_direction dir)
{
	__dma_page_dev_to_cpu(phys_to_page(paddr), paddr & (PAGE_SIZE - 1),
			      size, dir);
}

void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
		gfp_t gfp, unsigned long attrs)
{
	return __dma_alloc(dev, size, dma_handle, gfp,
			   __get_dma_pgprot(attrs, PAGE_KERNEL), false,
			   attrs, __builtin_return_address(0));
}

void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
		dma_addr_t dma_handle, unsigned long attrs)
{
	__arm_dma_free(dev, size, cpu_addr, dma_handle, attrs, false);
}