summaryrefslogtreecommitdiffstats
path: root/drivers/iommu/apple-dart.c
blob: 8af0242a90d91f40b62ed1ac3fd9a9ea1c8fe79b (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Apple DART (Device Address Resolution Table) IOMMU driver
 *
 * Copyright (C) 2021 The Asahi Linux Contributors
 *
 * Based on arm/arm-smmu/arm-ssmu.c and arm/arm-smmu-v3/arm-smmu-v3.c
 *  Copyright (C) 2013 ARM Limited
 *  Copyright (C) 2015 ARM Limited
 * and on exynos-iommu.c
 *  Copyright (c) 2011,2016 Samsung Electronics Co., Ltd.
 */

#include <linux/atomic.h>
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/dev_printk.h>
#include <linux/dma-iommu.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io-pgtable.h>
#include <linux/iommu.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_iommu.h>
#include <linux/of_platform.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/swab.h>
#include <linux/types.h>

#define DART_MAX_STREAMS 16
#define DART_MAX_TTBR 4
#define MAX_DARTS_PER_DEVICE 2

#define DART_STREAM_ALL 0xffff

#define DART_PARAMS1 0x00
#define DART_PARAMS_PAGE_SHIFT GENMASK(27, 24)

#define DART_PARAMS2 0x04
#define DART_PARAMS_BYPASS_SUPPORT BIT(0)

#define DART_STREAM_COMMAND 0x20
#define DART_STREAM_COMMAND_BUSY BIT(2)
#define DART_STREAM_COMMAND_INVALIDATE BIT(20)

#define DART_STREAM_SELECT 0x34

#define DART_ERROR 0x40
#define DART_ERROR_STREAM GENMASK(27, 24)
#define DART_ERROR_CODE GENMASK(11, 0)
#define DART_ERROR_FLAG BIT(31)

#define DART_ERROR_READ_FAULT BIT(4)
#define DART_ERROR_WRITE_FAULT BIT(3)
#define DART_ERROR_NO_PTE BIT(2)
#define DART_ERROR_NO_PMD BIT(1)
#define DART_ERROR_NO_TTBR BIT(0)

#define DART_CONFIG 0x60
#define DART_CONFIG_LOCK BIT(15)

#define DART_STREAM_COMMAND_BUSY_TIMEOUT 100

#define DART_ERROR_ADDR_HI 0x54
#define DART_ERROR_ADDR_LO 0x50

#define DART_STREAMS_ENABLE 0xfc

#define DART_TCR(sid) (0x100 + 4 * (sid))
#define DART_TCR_TRANSLATE_ENABLE BIT(7)
#define DART_TCR_BYPASS0_ENABLE BIT(8)
#define DART_TCR_BYPASS1_ENABLE BIT(12)

#define DART_TTBR(sid, idx) (0x200 + 16 * (sid) + 4 * (idx))
#define DART_TTBR_VALID BIT(31)
#define DART_TTBR_SHIFT 12

/*
 * Private structure associated with each DART device.
 *
 * @dev: device struct
 * @regs: mapped MMIO region
 * @irq: interrupt number, can be shared with other DARTs
 * @clks: clocks associated with this DART
 * @num_clks: number of @clks
 * @lock: lock for hardware operations involving this dart
 * @pgsize: pagesize supported by this DART
 * @supports_bypass: indicates if this DART supports bypass mode
 * @force_bypass: force bypass mode due to pagesize mismatch?
 * @sid2group: maps stream ids to iommu_groups
 * @iommu: iommu core device
 */
struct apple_dart {
	struct device *dev;

	void __iomem *regs;

	int irq;
	struct clk_bulk_data *clks;
	int num_clks;

	spinlock_t lock;

	u32 pgsize;
	u32 supports_bypass : 1;
	u32 force_bypass : 1;

	struct iommu_group *sid2group[DART_MAX_STREAMS];
	struct iommu_device iommu;
};

/*
 * Convenience struct to identify streams.
 *
 * The normal variant is used inside apple_dart_master_cfg which isn't written
 * to concurrently.
 * The atomic variant is used inside apple_dart_domain where we have to guard
 * against races from potential parallel calls to attach/detach_device.
 * Note that even inside the atomic variant the apple_dart pointer is not
 * protected: This pointer is initialized once under the domain init mutex
 * and never changed again afterwards. Devices with different dart pointers
 * cannot be attached to the same domain.
 *
 * @dart dart pointer
 * @sid stream id bitmap
 */
struct apple_dart_stream_map {
	struct apple_dart *dart;
	unsigned long sidmap;
};
struct apple_dart_atomic_stream_map {
	struct apple_dart *dart;
	atomic64_t sidmap;
};

/*
 * This structure is attached to each iommu domain handled by a DART.
 *
 * @pgtbl_ops: pagetable ops allocated by io-pgtable
 * @finalized: true if the domain has been completely initialized
 * @init_lock: protects domain initialization
 * @stream_maps: streams attached to this domain (valid for DMA/UNMANAGED only)
 * @domain: core iommu domain pointer
 */
struct apple_dart_domain {
	struct io_pgtable_ops *pgtbl_ops;

	bool finalized;
	struct mutex init_lock;
	struct apple_dart_atomic_stream_map stream_maps[MAX_DARTS_PER_DEVICE];

	struct iommu_domain domain;
};

/*
 * This structure is attached to devices with dev_iommu_priv_set() on of_xlate
 * and contains a list of streams bound to this device.
 * So far the worst case seen is a single device with two streams
 * from different darts, such that this simple static array is enough.
 *
 * @streams: streams for this device
 */
struct apple_dart_master_cfg {
	struct apple_dart_stream_map stream_maps[MAX_DARTS_PER_DEVICE];
};

/*
 * Helper macro to iterate over apple_dart_master_cfg.stream_maps and
 * apple_dart_domain.stream_maps
 *
 * @i int used as loop variable
 * @base pointer to base struct (apple_dart_master_cfg or apple_dart_domain)
 * @stream pointer to the apple_dart_streams struct for each loop iteration
 */
#define for_each_stream_map(i, base, stream_map)                               \
	for (i = 0, stream_map = &(base)->stream_maps[0];                      \
	     i < MAX_DARTS_PER_DEVICE && stream_map->dart;                     \
	     stream_map = &(base)->stream_maps[++i])

static struct platform_driver apple_dart_driver;
static const struct iommu_ops apple_dart_iommu_ops;

static struct apple_dart_domain *to_dart_domain(struct iommu_domain *dom)
{
	return container_of(dom, struct apple_dart_domain, domain);
}

static void
apple_dart_hw_enable_translation(struct apple_dart_stream_map *stream_map)
{
	int sid;

	for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS)
		writel(DART_TCR_TRANSLATE_ENABLE,
		       stream_map->dart->regs + DART_TCR(sid));
}

static void apple_dart_hw_disable_dma(struct apple_dart_stream_map *stream_map)
{
	int sid;

	for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS)
		writel(0, stream_map->dart->regs + DART_TCR(sid));
}

static void
apple_dart_hw_enable_bypass(struct apple_dart_stream_map *stream_map)
{
	int sid;

	WARN_ON(!stream_map->dart->supports_bypass);
	for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS)
		writel(DART_TCR_BYPASS0_ENABLE | DART_TCR_BYPASS1_ENABLE,
		       stream_map->dart->regs + DART_TCR(sid));
}

static void apple_dart_hw_set_ttbr(struct apple_dart_stream_map *stream_map,
				   u8 idx, phys_addr_t paddr)
{
	int sid;

	WARN_ON(paddr & ((1 << DART_TTBR_SHIFT) - 1));
	for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS)
		writel(DART_TTBR_VALID | (paddr >> DART_TTBR_SHIFT),
		       stream_map->dart->regs + DART_TTBR(sid, idx));
}

static void apple_dart_hw_clear_ttbr(struct apple_dart_stream_map *stream_map,
				     u8 idx)
{
	int sid;

	for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS)
		writel(0, stream_map->dart->regs + DART_TTBR(sid, idx));
}

static void
apple_dart_hw_clear_all_ttbrs(struct apple_dart_stream_map *stream_map)
{
	int i;

	for (i = 0; i < DART_MAX_TTBR; ++i)
		apple_dart_hw_clear_ttbr(stream_map, i);
}

static int
apple_dart_hw_stream_command(struct apple_dart_stream_map *stream_map,
			     u32 command)
{
	unsigned long flags;
	int ret;
	u32 command_reg;

	spin_lock_irqsave(&stream_map->dart->lock, flags);

	writel(stream_map->sidmap, stream_map->dart->regs + DART_STREAM_SELECT);
	writel(command, stream_map->dart->regs + DART_STREAM_COMMAND);

	ret = readl_poll_timeout_atomic(
		stream_map->dart->regs + DART_STREAM_COMMAND, command_reg,
		!(command_reg & DART_STREAM_COMMAND_BUSY), 1,
		DART_STREAM_COMMAND_BUSY_TIMEOUT);

	spin_unlock_irqrestore(&stream_map->dart->lock, flags);

	if (ret) {
		dev_err(stream_map->dart->dev,
			"busy bit did not clear after command %x for streams %lx\n",
			command, stream_map->sidmap);
		return ret;
	}

	return 0;
}

static int
apple_dart_hw_invalidate_tlb(struct apple_dart_stream_map *stream_map)
{
	return apple_dart_hw_stream_command(stream_map,
					    DART_STREAM_COMMAND_INVALIDATE);
}

static int apple_dart_hw_reset(struct apple_dart *dart)
{
	u32 config;
	struct apple_dart_stream_map stream_map;

	config = readl(dart->regs + DART_CONFIG);
	if (config & DART_CONFIG_LOCK) {
		dev_err(dart->dev, "DART is locked down until reboot: %08x\n",
			config);
		return -EINVAL;
	}

	stream_map.dart = dart;
	stream_map.sidmap = DART_STREAM_ALL;
	apple_dart_hw_disable_dma(&stream_map);
	apple_dart_hw_clear_all_ttbrs(&stream_map);

	/* enable all streams globally since TCR is used to control isolation */
	writel(DART_STREAM_ALL, dart->regs + DART_STREAMS_ENABLE);

	/* clear any pending errors before the interrupt is unmasked */
	writel(readl(dart->regs + DART_ERROR), dart->regs + DART_ERROR);

	return apple_dart_hw_invalidate_tlb(&stream_map);
}

static void apple_dart_domain_flush_tlb(struct apple_dart_domain *domain)
{
	int i;
	struct apple_dart_atomic_stream_map *domain_stream_map;
	struct apple_dart_stream_map stream_map;

	for_each_stream_map(i, domain, domain_stream_map) {
		stream_map.dart = domain_stream_map->dart;
		stream_map.sidmap = atomic64_read(&domain_stream_map->sidmap);
		apple_dart_hw_invalidate_tlb(&stream_map);
	}
}

static void apple_dart_flush_iotlb_all(struct iommu_domain *domain)
{
	apple_dart_domain_flush_tlb(to_dart_domain(domain));
}

static void apple_dart_iotlb_sync(struct iommu_domain *domain,
				  struct iommu_iotlb_gather *gather)
{
	apple_dart_domain_flush_tlb(to_dart_domain(domain));
}

static void apple_dart_iotlb_sync_map(struct iommu_domain *domain,
				      unsigned long iova, size_t size)
{
	apple_dart_domain_flush_tlb(to_dart_domain(domain));
}

static phys_addr_t apple_dart_iova_to_phys(struct iommu_domain *domain,
					   dma_addr_t iova)
{
	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
	struct io_pgtable_ops *ops = dart_domain->pgtbl_ops;

	if (!ops)
		return 0;

	return ops->iova_to_phys(ops, iova);
}

static int apple_dart_map_pages(struct iommu_domain *domain, unsigned long iova,
				phys_addr_t paddr, size_t pgsize,
				size_t pgcount, int prot, gfp_t gfp,
				size_t *mapped)
{
	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
	struct io_pgtable_ops *ops = dart_domain->pgtbl_ops;

	if (!ops)
		return -ENODEV;

	return ops->map_pages(ops, iova, paddr, pgsize, pgcount, prot, gfp,
			      mapped);
}

static size_t apple_dart_unmap_pages(struct iommu_domain *domain,
				     unsigned long iova, size_t pgsize,
				     size_t pgcount,
				     struct iommu_iotlb_gather *gather)
{
	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
	struct io_pgtable_ops *ops = dart_domain->pgtbl_ops;

	return ops->unmap_pages(ops, iova, pgsize, pgcount, gather);
}

static void
apple_dart_setup_translation(struct apple_dart_domain *domain,
			     struct apple_dart_stream_map *stream_map)
{
	int i;
	struct io_pgtable_cfg *pgtbl_cfg =
		&io_pgtable_ops_to_pgtable(domain->pgtbl_ops)->cfg;

	for (i = 0; i < pgtbl_cfg->apple_dart_cfg.n_ttbrs; ++i)
		apple_dart_hw_set_ttbr(stream_map, i,
				       pgtbl_cfg->apple_dart_cfg.ttbr[i]);
	for (; i < DART_MAX_TTBR; ++i)
		apple_dart_hw_clear_ttbr(stream_map, i);

	apple_dart_hw_enable_translation(stream_map);
	apple_dart_hw_invalidate_tlb(stream_map);
}

static int apple_dart_finalize_domain(struct iommu_domain *domain,
				      struct apple_dart_master_cfg *cfg)
{
	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
	struct apple_dart *dart = cfg->stream_maps[0].dart;
	struct io_pgtable_cfg pgtbl_cfg;
	int ret = 0;
	int i;

	mutex_lock(&dart_domain->init_lock);

	if (dart_domain->finalized)
		goto done;

	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
		dart_domain->stream_maps[i].dart = cfg->stream_maps[i].dart;
		atomic64_set(&dart_domain->stream_maps[i].sidmap,
			     cfg->stream_maps[i].sidmap);
	}

	pgtbl_cfg = (struct io_pgtable_cfg){
		.pgsize_bitmap = dart->pgsize,
		.ias = 32,
		.oas = 36,
		.coherent_walk = 1,
		.iommu_dev = dart->dev,
	};

	dart_domain->pgtbl_ops =
		alloc_io_pgtable_ops(APPLE_DART, &pgtbl_cfg, domain);
	if (!dart_domain->pgtbl_ops) {
		ret = -ENOMEM;
		goto done;
	}

	domain->pgsize_bitmap = pgtbl_cfg.pgsize_bitmap;
	domain->geometry.aperture_start = 0;
	domain->geometry.aperture_end = DMA_BIT_MASK(32);
	domain->geometry.force_aperture = true;

	dart_domain->finalized = true;

done:
	mutex_unlock(&dart_domain->init_lock);
	return ret;
}

static int
apple_dart_mod_streams(struct apple_dart_atomic_stream_map *domain_maps,
		       struct apple_dart_stream_map *master_maps,
		       bool add_streams)
{
	int i;

	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
		if (domain_maps[i].dart != master_maps[i].dart)
			return -EINVAL;
	}

	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
		if (!domain_maps[i].dart)
			break;
		if (add_streams)
			atomic64_or(master_maps[i].sidmap,
				    &domain_maps[i].sidmap);
		else
			atomic64_and(~master_maps[i].sidmap,
				     &domain_maps[i].sidmap);
	}

	return 0;
}

static int apple_dart_domain_add_streams(struct apple_dart_domain *domain,
					 struct apple_dart_master_cfg *cfg)
{
	return apple_dart_mod_streams(domain->stream_maps, cfg->stream_maps,
				      true);
}

static int apple_dart_domain_remove_streams(struct apple_dart_domain *domain,
					    struct apple_dart_master_cfg *cfg)
{
	return apple_dart_mod_streams(domain->stream_maps, cfg->stream_maps,
				      false);
}

static int apple_dart_attach_dev(struct iommu_domain *domain,
				 struct device *dev)
{
	int ret, i;
	struct apple_dart_stream_map *stream_map;
	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
	struct apple_dart_domain *dart_domain = to_dart_domain(domain);

	if (cfg->stream_maps[0].dart->force_bypass &&
	    domain->type != IOMMU_DOMAIN_IDENTITY)
		return -EINVAL;
	if (!cfg->stream_maps[0].dart->supports_bypass &&
	    domain->type == IOMMU_DOMAIN_IDENTITY)
		return -EINVAL;

	ret = apple_dart_finalize_domain(domain, cfg);
	if (ret)
		return ret;

	switch (domain->type) {
	case IOMMU_DOMAIN_DMA:
	case IOMMU_DOMAIN_UNMANAGED:
		ret = apple_dart_domain_add_streams(dart_domain, cfg);
		if (ret)
			return ret;

		for_each_stream_map(i, cfg, stream_map)
			apple_dart_setup_translation(dart_domain, stream_map);
		break;
	case IOMMU_DOMAIN_BLOCKED:
		for_each_stream_map(i, cfg, stream_map)
			apple_dart_hw_disable_dma(stream_map);
		break;
	case IOMMU_DOMAIN_IDENTITY:
		for_each_stream_map(i, cfg, stream_map)
			apple_dart_hw_enable_bypass(stream_map);
		break;
	}

	return ret;
}

static void apple_dart_detach_dev(struct iommu_domain *domain,
				  struct device *dev)
{
	int i;
	struct apple_dart_stream_map *stream_map;
	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
	struct apple_dart_domain *dart_domain = to_dart_domain(domain);

	for_each_stream_map(i, cfg, stream_map)
		apple_dart_hw_disable_dma(stream_map);

	if (domain->type == IOMMU_DOMAIN_DMA ||
	    domain->type == IOMMU_DOMAIN_UNMANAGED)
		apple_dart_domain_remove_streams(dart_domain, cfg);
}

static struct iommu_device *apple_dart_probe_device(struct device *dev)
{
	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
	struct apple_dart_stream_map *stream_map;
	int i;

	if (!cfg)
		return ERR_PTR(-ENODEV);

	for_each_stream_map(i, cfg, stream_map)
		device_link_add(
			dev, stream_map->dart->dev,
			DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER);

	return &cfg->stream_maps[0].dart->iommu;
}

static void apple_dart_release_device(struct device *dev)
{
	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);

	if (!cfg)
		return;

	dev_iommu_priv_set(dev, NULL);
	kfree(cfg);
}

static struct iommu_domain *apple_dart_domain_alloc(unsigned int type)
{
	struct apple_dart_domain *dart_domain;

	if (type != IOMMU_DOMAIN_DMA && type != IOMMU_DOMAIN_UNMANAGED &&
	    type != IOMMU_DOMAIN_IDENTITY && type != IOMMU_DOMAIN_BLOCKED)
		return NULL;

	dart_domain = kzalloc(sizeof(*dart_domain), GFP_KERNEL);
	if (!dart_domain)
		return NULL;

	mutex_init(&dart_domain->init_lock);

	/* no need to allocate pgtbl_ops or do any other finalization steps */
	if (type == IOMMU_DOMAIN_IDENTITY || type == IOMMU_DOMAIN_BLOCKED)
		dart_domain->finalized = true;

	return &dart_domain->domain;
}

static void apple_dart_domain_free(struct iommu_domain *domain)
{
	struct apple_dart_domain *dart_domain = to_dart_domain(domain);

	if (dart_domain->pgtbl_ops)
		free_io_pgtable_ops(dart_domain->pgtbl_ops);

	kfree(dart_domain);
}

static int apple_dart_of_xlate(struct device *dev, struct of_phandle_args *args)
{
	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
	struct platform_device *iommu_pdev = of_find_device_by_node(args->np);
	struct apple_dart *dart = platform_get_drvdata(iommu_pdev);
	struct apple_dart *cfg_dart;
	int i, sid;

	if (args->args_count != 1)
		return -EINVAL;
	sid = args->args[0];

	if (!cfg)
		cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
	if (!cfg)
		return -ENOMEM;
	dev_iommu_priv_set(dev, cfg);

	cfg_dart = cfg->stream_maps[0].dart;
	if (cfg_dart) {
		if (cfg_dart->supports_bypass != dart->supports_bypass)
			return -EINVAL;
		if (cfg_dart->force_bypass != dart->force_bypass)
			return -EINVAL;
		if (cfg_dart->pgsize != dart->pgsize)
			return -EINVAL;
	}

	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
		if (cfg->stream_maps[i].dart == dart) {
			cfg->stream_maps[i].sidmap |= 1 << sid;
			return 0;
		}
	}
	for (i = 0; i < MAX_DARTS_PER_DEVICE; ++i) {
		if (!cfg->stream_maps[i].dart) {
			cfg->stream_maps[i].dart = dart;
			cfg->stream_maps[i].sidmap = 1 << sid;
			return 0;
		}
	}

	return -EINVAL;
}

static DEFINE_MUTEX(apple_dart_groups_lock);

static void apple_dart_release_group(void *iommu_data)
{
	int i, sid;
	struct apple_dart_stream_map *stream_map;
	struct apple_dart_master_cfg *group_master_cfg = iommu_data;

	mutex_lock(&apple_dart_groups_lock);

	for_each_stream_map(i, group_master_cfg, stream_map)
		for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS)
			stream_map->dart->sid2group[sid] = NULL;

	kfree(iommu_data);
	mutex_unlock(&apple_dart_groups_lock);
}

static struct iommu_group *apple_dart_device_group(struct device *dev)
{
	int i, sid;
	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
	struct apple_dart_stream_map *stream_map;
	struct apple_dart_master_cfg *group_master_cfg;
	struct iommu_group *group = NULL;
	struct iommu_group *res = ERR_PTR(-EINVAL);

	mutex_lock(&apple_dart_groups_lock);

	for_each_stream_map(i, cfg, stream_map) {
		for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS) {
			struct iommu_group *stream_group =
				stream_map->dart->sid2group[sid];

			if (group && group != stream_group) {
				res = ERR_PTR(-EINVAL);
				goto out;
			}

			group = stream_group;
		}
	}

	if (group) {
		res = iommu_group_ref_get(group);
		goto out;
	}

#ifdef CONFIG_PCI
	if (dev_is_pci(dev))
		group = pci_device_group(dev);
	else
#endif
		group = generic_device_group(dev);

	res = ERR_PTR(-ENOMEM);
	if (!group)
		goto out;

	group_master_cfg = kmemdup(cfg, sizeof(*group_master_cfg), GFP_KERNEL);
	if (!group_master_cfg) {
		iommu_group_put(group);
		goto out;
	}

	iommu_group_set_iommudata(group, group_master_cfg,
		apple_dart_release_group);

	for_each_stream_map(i, cfg, stream_map)
		for_each_set_bit(sid, &stream_map->sidmap, DART_MAX_STREAMS)
			stream_map->dart->sid2group[sid] = group;

	res = group;

out:
	mutex_unlock(&apple_dart_groups_lock);
	return res;
}

static int apple_dart_def_domain_type(struct device *dev)
{
	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);

	if (cfg->stream_maps[0].dart->force_bypass)
		return IOMMU_DOMAIN_IDENTITY;
	if (!cfg->stream_maps[0].dart->supports_bypass)
		return IOMMU_DOMAIN_DMA;

	return 0;
}

#ifndef CONFIG_PCIE_APPLE_MSI_DOORBELL_ADDR
/* Keep things compiling when CONFIG_PCI_APPLE isn't selected */
#define CONFIG_PCIE_APPLE_MSI_DOORBELL_ADDR	0
#endif
#define DOORBELL_ADDR	(CONFIG_PCIE_APPLE_MSI_DOORBELL_ADDR & PAGE_MASK)

static void apple_dart_get_resv_regions(struct device *dev,
					struct list_head *head)
{
	if (IS_ENABLED(CONFIG_PCIE_APPLE) && dev_is_pci(dev)) {
		struct iommu_resv_region *region;
		int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;

		region = iommu_alloc_resv_region(DOORBELL_ADDR,
						 PAGE_SIZE, prot,
						 IOMMU_RESV_MSI);
		if (!region)
			return;

		list_add_tail(&region->list, head);
	}

	iommu_dma_get_resv_regions(dev, head);
}

static const struct iommu_ops apple_dart_iommu_ops = {
	.domain_alloc = apple_dart_domain_alloc,
	.probe_device = apple_dart_probe_device,
	.release_device = apple_dart_release_device,
	.device_group = apple_dart_device_group,
	.of_xlate = apple_dart_of_xlate,
	.def_domain_type = apple_dart_def_domain_type,
	.get_resv_regions = apple_dart_get_resv_regions,
	.put_resv_regions = generic_iommu_put_resv_regions,
	.pgsize_bitmap = -1UL, /* Restricted during dart probe */
	.owner = THIS_MODULE,
	.default_domain_ops = &(const struct iommu_domain_ops) {
		.attach_dev	= apple_dart_attach_dev,
		.detach_dev	= apple_dart_detach_dev,
		.map_pages	= apple_dart_map_pages,
		.unmap_pages	= apple_dart_unmap_pages,
		.flush_iotlb_all = apple_dart_flush_iotlb_all,
		.iotlb_sync	= apple_dart_iotlb_sync,
		.iotlb_sync_map	= apple_dart_iotlb_sync_map,
		.iova_to_phys	= apple_dart_iova_to_phys,
		.free		= apple_dart_domain_free,
	}
};

static irqreturn_t apple_dart_irq(int irq, void *dev)
{
	struct apple_dart *dart = dev;
	const char *fault_name = NULL;
	u32 error = readl(dart->regs + DART_ERROR);
	u32 error_code = FIELD_GET(DART_ERROR_CODE, error);
	u32 addr_lo = readl(dart->regs + DART_ERROR_ADDR_LO);
	u32 addr_hi = readl(dart->regs + DART_ERROR_ADDR_HI);
	u64 addr = addr_lo | (((u64)addr_hi) << 32);
	u8 stream_idx = FIELD_GET(DART_ERROR_STREAM, error);

	if (!(error & DART_ERROR_FLAG))
		return IRQ_NONE;

	/* there should only be a single bit set but let's use == to be sure */
	if (error_code == DART_ERROR_READ_FAULT)
		fault_name = "READ FAULT";
	else if (error_code == DART_ERROR_WRITE_FAULT)
		fault_name = "WRITE FAULT";
	else if (error_code == DART_ERROR_NO_PTE)
		fault_name = "NO PTE FOR IOVA";
	else if (error_code == DART_ERROR_NO_PMD)
		fault_name = "NO PMD FOR IOVA";
	else if (error_code == DART_ERROR_NO_TTBR)
		fault_name = "NO TTBR FOR IOVA";
	else
		fault_name = "unknown";

	dev_err_ratelimited(
		dart->dev,
		"translation fault: status:0x%x stream:%d code:0x%x (%s) at 0x%llx",
		error, stream_idx, error_code, fault_name, addr);

	writel(error, dart->regs + DART_ERROR);
	return IRQ_HANDLED;
}

static int apple_dart_set_bus_ops(const struct iommu_ops *ops)
{
	int ret;

	if (!iommu_present(&platform_bus_type)) {
		ret = bus_set_iommu(&platform_bus_type, ops);
		if (ret)
			return ret;
	}
#ifdef CONFIG_PCI
	if (!iommu_present(&pci_bus_type)) {
		ret = bus_set_iommu(&pci_bus_type, ops);
		if (ret) {
			bus_set_iommu(&platform_bus_type, NULL);
			return ret;
		}
	}
#endif
	return 0;
}

static int apple_dart_probe(struct platform_device *pdev)
{
	int ret;
	u32 dart_params[2];
	struct resource *res;
	struct apple_dart *dart;
	struct device *dev = &pdev->dev;

	dart = devm_kzalloc(dev, sizeof(*dart), GFP_KERNEL);
	if (!dart)
		return -ENOMEM;

	dart->dev = dev;
	spin_lock_init(&dart->lock);

	dart->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
	if (IS_ERR(dart->regs))
		return PTR_ERR(dart->regs);

	if (resource_size(res) < 0x4000) {
		dev_err(dev, "MMIO region too small (%pr)\n", res);
		return -EINVAL;
	}

	dart->irq = platform_get_irq(pdev, 0);
	if (dart->irq < 0)
		return -ENODEV;

	ret = devm_clk_bulk_get_all(dev, &dart->clks);
	if (ret < 0)
		return ret;
	dart->num_clks = ret;

	ret = clk_bulk_prepare_enable(dart->num_clks, dart->clks);
	if (ret)
		return ret;

	ret = apple_dart_hw_reset(dart);
	if (ret)
		goto err_clk_disable;

	dart_params[0] = readl(dart->regs + DART_PARAMS1);
	dart_params[1] = readl(dart->regs + DART_PARAMS2);
	dart->pgsize = 1 << FIELD_GET(DART_PARAMS_PAGE_SHIFT, dart_params[0]);
	dart->supports_bypass = dart_params[1] & DART_PARAMS_BYPASS_SUPPORT;
	dart->force_bypass = dart->pgsize > PAGE_SIZE;

	ret = request_irq(dart->irq, apple_dart_irq, IRQF_SHARED,
			  "apple-dart fault handler", dart);
	if (ret)
		goto err_clk_disable;

	platform_set_drvdata(pdev, dart);

	ret = apple_dart_set_bus_ops(&apple_dart_iommu_ops);
	if (ret)
		goto err_free_irq;

	ret = iommu_device_sysfs_add(&dart->iommu, dev, NULL, "apple-dart.%s",
				     dev_name(&pdev->dev));
	if (ret)
		goto err_remove_bus_ops;

	ret = iommu_device_register(&dart->iommu, &apple_dart_iommu_ops, dev);
	if (ret)
		goto err_sysfs_remove;

	dev_info(
		&pdev->dev,
		"DART [pagesize %x, bypass support: %d, bypass forced: %d] initialized\n",
		dart->pgsize, dart->supports_bypass, dart->force_bypass);
	return 0;

err_sysfs_remove:
	iommu_device_sysfs_remove(&dart->iommu);
err_remove_bus_ops:
	apple_dart_set_bus_ops(NULL);
err_free_irq:
	free_irq(dart->irq, dart);
err_clk_disable:
	clk_bulk_disable_unprepare(dart->num_clks, dart->clks);

	return ret;
}

static int apple_dart_remove(struct platform_device *pdev)
{
	struct apple_dart *dart = platform_get_drvdata(pdev);

	apple_dart_hw_reset(dart);
	free_irq(dart->irq, dart);
	apple_dart_set_bus_ops(NULL);

	iommu_device_unregister(&dart->iommu);
	iommu_device_sysfs_remove(&dart->iommu);

	clk_bulk_disable_unprepare(dart->num_clks, dart->clks);

	return 0;
}

static const struct of_device_id apple_dart_of_match[] = {
	{ .compatible = "apple,t8103-dart", .data = NULL },
	{},
};
MODULE_DEVICE_TABLE(of, apple_dart_of_match);

static struct platform_driver apple_dart_driver = {
	.driver	= {
		.name			= "apple-dart",
		.of_match_table		= apple_dart_of_match,
		.suppress_bind_attrs    = true,
	},
	.probe	= apple_dart_probe,
	.remove	= apple_dart_remove,
};

module_platform_driver(apple_dart_driver);

MODULE_DESCRIPTION("IOMMU API for Apple's DART");
MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
MODULE_LICENSE("GPL v2");