summaryrefslogtreecommitdiffstats
path: root/drivers/iommu/tegra-smmu.c
blob: 6e134c7c227fced6a0c186f3e403fc6d9e1d49f7 (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
/*
 * Copyright (C) 2011-2014 NVIDIA CORPORATION.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/err.h>
#include <linux/iommu.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <soc/tegra/ahb.h>
#include <soc/tegra/mc.h>

struct tegra_smmu {
	void __iomem *regs;
	struct device *dev;

	struct tegra_mc *mc;
	const struct tegra_smmu_soc *soc;

	unsigned long *asids;
	struct mutex lock;

	struct list_head list;
};

struct tegra_smmu_as {
	struct iommu_domain *domain;
	struct tegra_smmu *smmu;
	unsigned int use_count;
	struct page *count;
	struct page *pd;
	unsigned id;
	u32 attr;
};

static inline void smmu_writel(struct tegra_smmu *smmu, u32 value,
			       unsigned long offset)
{
	writel(value, smmu->regs + offset);
}

static inline u32 smmu_readl(struct tegra_smmu *smmu, unsigned long offset)
{
	return readl(smmu->regs + offset);
}

#define SMMU_CONFIG 0x010
#define  SMMU_CONFIG_ENABLE (1 << 0)

#define SMMU_TLB_CONFIG 0x14
#define  SMMU_TLB_CONFIG_HIT_UNDER_MISS (1 << 29)
#define  SMMU_TLB_CONFIG_ROUND_ROBIN_ARBITRATION (1 << 28)
#define  SMMU_TLB_CONFIG_ACTIVE_LINES(x) ((x) & 0x3f)

#define SMMU_PTC_CONFIG 0x18
#define  SMMU_PTC_CONFIG_ENABLE (1 << 29)
#define  SMMU_PTC_CONFIG_REQ_LIMIT(x) (((x) & 0x0f) << 24)
#define  SMMU_PTC_CONFIG_INDEX_MAP(x) ((x) & 0x3f)

#define SMMU_PTB_ASID 0x01c
#define  SMMU_PTB_ASID_VALUE(x) ((x) & 0x7f)

#define SMMU_PTB_DATA 0x020
#define  SMMU_PTB_DATA_VALUE(page, attr) (page_to_phys(page) >> 12 | (attr))

#define SMMU_MK_PDE(page, attr) (page_to_phys(page) >> SMMU_PTE_SHIFT | (attr))

#define SMMU_TLB_FLUSH 0x030
#define  SMMU_TLB_FLUSH_VA_MATCH_ALL     (0 << 0)
#define  SMMU_TLB_FLUSH_VA_MATCH_SECTION (2 << 0)
#define  SMMU_TLB_FLUSH_VA_MATCH_GROUP   (3 << 0)
#define  SMMU_TLB_FLUSH_ASID(x)          (((x) & 0x7f) << 24)
#define  SMMU_TLB_FLUSH_VA_SECTION(addr) ((((addr) & 0xffc00000) >> 12) | \
					  SMMU_TLB_FLUSH_VA_MATCH_SECTION)
#define  SMMU_TLB_FLUSH_VA_GROUP(addr)   ((((addr) & 0xffffc000) >> 12) | \
					  SMMU_TLB_FLUSH_VA_MATCH_GROUP)
#define  SMMU_TLB_FLUSH_ASID_MATCH       (1 << 31)

#define SMMU_PTC_FLUSH 0x034
#define  SMMU_PTC_FLUSH_TYPE_ALL (0 << 0)
#define  SMMU_PTC_FLUSH_TYPE_ADR (1 << 0)

#define SMMU_PTC_FLUSH_HI 0x9b8
#define  SMMU_PTC_FLUSH_HI_MASK 0x3

/* per-SWGROUP SMMU_*_ASID register */
#define SMMU_ASID_ENABLE (1 << 31)
#define SMMU_ASID_MASK 0x7f
#define SMMU_ASID_VALUE(x) ((x) & SMMU_ASID_MASK)

/* page table definitions */
#define SMMU_NUM_PDE 1024
#define SMMU_NUM_PTE 1024

#define SMMU_SIZE_PD (SMMU_NUM_PDE * 4)
#define SMMU_SIZE_PT (SMMU_NUM_PTE * 4)

#define SMMU_PDE_SHIFT 22
#define SMMU_PTE_SHIFT 12

#define SMMU_PFN_MASK 0x000fffff

#define SMMU_PD_READABLE	(1 << 31)
#define SMMU_PD_WRITABLE	(1 << 30)
#define SMMU_PD_NONSECURE	(1 << 29)

#define SMMU_PDE_READABLE	(1 << 31)
#define SMMU_PDE_WRITABLE	(1 << 30)
#define SMMU_PDE_NONSECURE	(1 << 29)
#define SMMU_PDE_NEXT		(1 << 28)

#define SMMU_PTE_READABLE	(1 << 31)
#define SMMU_PTE_WRITABLE	(1 << 30)
#define SMMU_PTE_NONSECURE	(1 << 29)

#define SMMU_PDE_ATTR		(SMMU_PDE_READABLE | SMMU_PDE_WRITABLE | \
				 SMMU_PDE_NONSECURE)
#define SMMU_PTE_ATTR		(SMMU_PTE_READABLE | SMMU_PTE_WRITABLE | \
				 SMMU_PTE_NONSECURE)

static inline void smmu_flush_ptc(struct tegra_smmu *smmu, struct page *page,
				  unsigned long offset)
{
	phys_addr_t phys = page ? page_to_phys(page) : 0;
	u32 value;

	if (page) {
		offset &= ~(smmu->mc->soc->atom_size - 1);

		if (smmu->mc->soc->num_address_bits > 32) {
#ifdef CONFIG_PHYS_ADDR_T_64BIT
			value = (phys >> 32) & SMMU_PTC_FLUSH_HI_MASK;
#else
			value = 0;
#endif
			smmu_writel(smmu, value, SMMU_PTC_FLUSH_HI);
		}

		value = (phys + offset) | SMMU_PTC_FLUSH_TYPE_ADR;
	} else {
		value = SMMU_PTC_FLUSH_TYPE_ALL;
	}

	smmu_writel(smmu, value, SMMU_PTC_FLUSH);
}

static inline void smmu_flush_tlb(struct tegra_smmu *smmu)
{
	smmu_writel(smmu, SMMU_TLB_FLUSH_VA_MATCH_ALL, SMMU_TLB_FLUSH);
}

static inline void smmu_flush_tlb_asid(struct tegra_smmu *smmu,
				       unsigned long asid)
{
	u32 value;

	value = SMMU_TLB_FLUSH_ASID_MATCH | SMMU_TLB_FLUSH_ASID(asid) |
		SMMU_TLB_FLUSH_VA_MATCH_ALL;
	smmu_writel(smmu, value, SMMU_TLB_FLUSH);
}

static inline void smmu_flush_tlb_section(struct tegra_smmu *smmu,
					  unsigned long asid,
					  unsigned long iova)
{
	u32 value;

	value = SMMU_TLB_FLUSH_ASID_MATCH | SMMU_TLB_FLUSH_ASID(asid) |
		SMMU_TLB_FLUSH_VA_SECTION(iova);
	smmu_writel(smmu, value, SMMU_TLB_FLUSH);
}

static inline void smmu_flush_tlb_group(struct tegra_smmu *smmu,
					unsigned long asid,
					unsigned long iova)
{
	u32 value;

	value = SMMU_TLB_FLUSH_ASID_MATCH | SMMU_TLB_FLUSH_ASID(asid) |
		SMMU_TLB_FLUSH_VA_GROUP(iova);
	smmu_writel(smmu, value, SMMU_TLB_FLUSH);
}

static inline void smmu_flush(struct tegra_smmu *smmu)
{
	smmu_readl(smmu, SMMU_CONFIG);
}

static int tegra_smmu_alloc_asid(struct tegra_smmu *smmu, unsigned int *idp)
{
	unsigned long id;

	mutex_lock(&smmu->lock);

	id = find_first_zero_bit(smmu->asids, smmu->soc->num_asids);
	if (id >= smmu->soc->num_asids) {
		mutex_unlock(&smmu->lock);
		return -ENOSPC;
	}

	set_bit(id, smmu->asids);
	*idp = id;

	mutex_unlock(&smmu->lock);
	return 0;
}

static void tegra_smmu_free_asid(struct tegra_smmu *smmu, unsigned int id)
{
	mutex_lock(&smmu->lock);
	clear_bit(id, smmu->asids);
	mutex_unlock(&smmu->lock);
}

static bool tegra_smmu_capable(enum iommu_cap cap)
{
	return false;
}

static int tegra_smmu_domain_init(struct iommu_domain *domain)
{
	struct tegra_smmu_as *as;
	unsigned int i;
	uint32_t *pd;

	as = kzalloc(sizeof(*as), GFP_KERNEL);
	if (!as)
		return -ENOMEM;

	as->attr = SMMU_PD_READABLE | SMMU_PD_WRITABLE | SMMU_PD_NONSECURE;
	as->domain = domain;

	as->pd = alloc_page(GFP_KERNEL | __GFP_DMA);
	if (!as->pd) {
		kfree(as);
		return -ENOMEM;
	}

	as->count = alloc_page(GFP_KERNEL);
	if (!as->count) {
		__free_page(as->pd);
		kfree(as);
		return -ENOMEM;
	}

	/* clear PDEs */
	pd = page_address(as->pd);
	SetPageReserved(as->pd);

	for (i = 0; i < SMMU_NUM_PDE; i++)
		pd[i] = 0;

	/* clear PDE usage counters */
	pd = page_address(as->count);
	SetPageReserved(as->count);

	for (i = 0; i < SMMU_NUM_PDE; i++)
		pd[i] = 0;

	domain->priv = as;

	return 0;
}

static void tegra_smmu_domain_destroy(struct iommu_domain *domain)
{
	struct tegra_smmu_as *as = domain->priv;

	/* TODO: free page directory and page tables */
	ClearPageReserved(as->pd);

	kfree(as);
}

static const struct tegra_smmu_swgroup *
tegra_smmu_find_swgroup(struct tegra_smmu *smmu, unsigned int swgroup)
{
	const struct tegra_smmu_swgroup *group = NULL;
	unsigned int i;

	for (i = 0; i < smmu->soc->num_swgroups; i++) {
		if (smmu->soc->swgroups[i].swgroup == swgroup) {
			group = &smmu->soc->swgroups[i];
			break;
		}
	}

	return group;
}

static void tegra_smmu_enable(struct tegra_smmu *smmu, unsigned int swgroup,
			      unsigned int asid)
{
	const struct tegra_smmu_swgroup *group;
	unsigned int i;
	u32 value;

	for (i = 0; i < smmu->soc->num_clients; i++) {
		const struct tegra_mc_client *client = &smmu->soc->clients[i];

		if (client->swgroup != swgroup)
			continue;

		value = smmu_readl(smmu, client->smmu.reg);
		value |= BIT(client->smmu.bit);
		smmu_writel(smmu, value, client->smmu.reg);
	}

	group = tegra_smmu_find_swgroup(smmu, swgroup);
	if (group) {
		value = smmu_readl(smmu, group->reg);
		value &= ~SMMU_ASID_MASK;
		value |= SMMU_ASID_VALUE(asid);
		value |= SMMU_ASID_ENABLE;
		smmu_writel(smmu, value, group->reg);
	}
}

static void tegra_smmu_disable(struct tegra_smmu *smmu, unsigned int swgroup,
			       unsigned int asid)
{
	const struct tegra_smmu_swgroup *group;
	unsigned int i;
	u32 value;

	group = tegra_smmu_find_swgroup(smmu, swgroup);
	if (group) {
		value = smmu_readl(smmu, group->reg);
		value &= ~SMMU_ASID_MASK;
		value |= SMMU_ASID_VALUE(asid);
		value &= ~SMMU_ASID_ENABLE;
		smmu_writel(smmu, value, group->reg);
	}

	for (i = 0; i < smmu->soc->num_clients; i++) {
		const struct tegra_mc_client *client = &smmu->soc->clients[i];

		if (client->swgroup != swgroup)
			continue;

		value = smmu_readl(smmu, client->smmu.reg);
		value &= ~BIT(client->smmu.bit);
		smmu_writel(smmu, value, client->smmu.reg);
	}
}

static int tegra_smmu_as_prepare(struct tegra_smmu *smmu,
				 struct tegra_smmu_as *as)
{
	u32 value;
	int err;

	if (as->use_count > 0) {
		as->use_count++;
		return 0;
	}

	err = tegra_smmu_alloc_asid(smmu, &as->id);
	if (err < 0)
		return err;

	smmu->soc->ops->flush_dcache(as->pd, 0, SMMU_SIZE_PD);
	smmu_flush_ptc(smmu, as->pd, 0);
	smmu_flush_tlb_asid(smmu, as->id);

	smmu_writel(smmu, as->id & 0x7f, SMMU_PTB_ASID);
	value = SMMU_PTB_DATA_VALUE(as->pd, as->attr);
	smmu_writel(smmu, value, SMMU_PTB_DATA);
	smmu_flush(smmu);

	as->smmu = smmu;
	as->use_count++;

	return 0;
}

static void tegra_smmu_as_unprepare(struct tegra_smmu *smmu,
				    struct tegra_smmu_as *as)
{
	if (--as->use_count > 0)
		return;

	tegra_smmu_free_asid(smmu, as->id);
	as->smmu = NULL;
}

static int tegra_smmu_attach_dev(struct iommu_domain *domain,
				 struct device *dev)
{
	struct tegra_smmu *smmu = dev->archdata.iommu;
	struct tegra_smmu_as *as = domain->priv;
	struct device_node *np = dev->of_node;
	struct of_phandle_args args;
	unsigned int index = 0;
	int err = 0;

	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
					   &args)) {
		unsigned int swgroup = args.args[0];

		if (args.np != smmu->dev->of_node) {
			of_node_put(args.np);
			continue;
		}

		of_node_put(args.np);

		err = tegra_smmu_as_prepare(smmu, as);
		if (err < 0)
			return err;

		tegra_smmu_enable(smmu, swgroup, as->id);
		index++;
	}

	if (index == 0)
		return -ENODEV;

	return 0;
}

static void tegra_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
{
	struct tegra_smmu_as *as = domain->priv;
	struct device_node *np = dev->of_node;
	struct tegra_smmu *smmu = as->smmu;
	struct of_phandle_args args;
	unsigned int index = 0;

	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
					   &args)) {
		unsigned int swgroup = args.args[0];

		if (args.np != smmu->dev->of_node) {
			of_node_put(args.np);
			continue;
		}

		of_node_put(args.np);

		tegra_smmu_disable(smmu, swgroup, as->id);
		tegra_smmu_as_unprepare(smmu, as);
		index++;
	}
}

static u32 *as_get_pte(struct tegra_smmu_as *as, dma_addr_t iova,
		       struct page **pagep)
{
	u32 *pd = page_address(as->pd), *pt, *count;
	u32 pde = (iova >> SMMU_PDE_SHIFT) & 0x3ff;
	u32 pte = (iova >> SMMU_PTE_SHIFT) & 0x3ff;
	struct tegra_smmu *smmu = as->smmu;
	struct page *page;
	unsigned int i;

	if (pd[pde] == 0) {
		page = alloc_page(GFP_KERNEL | __GFP_DMA);
		if (!page)
			return NULL;

		pt = page_address(page);
		SetPageReserved(page);

		for (i = 0; i < SMMU_NUM_PTE; i++)
			pt[i] = 0;

		smmu->soc->ops->flush_dcache(page, 0, SMMU_SIZE_PT);

		pd[pde] = SMMU_MK_PDE(page, SMMU_PDE_ATTR | SMMU_PDE_NEXT);

		smmu->soc->ops->flush_dcache(as->pd, pde << 2, 4);
		smmu_flush_ptc(smmu, as->pd, pde << 2);
		smmu_flush_tlb_section(smmu, as->id, iova);
		smmu_flush(smmu);
	} else {
		page = pfn_to_page(pd[pde] & SMMU_PFN_MASK);
		pt = page_address(page);
	}

	*pagep = page;

	/* Keep track of entries in this page table. */
	count = page_address(as->count);
	if (pt[pte] == 0)
		count[pde]++;

	return &pt[pte];
}

static void as_put_pte(struct tegra_smmu_as *as, dma_addr_t iova)
{
	u32 pde = (iova >> SMMU_PDE_SHIFT) & 0x3ff;
	u32 pte = (iova >> SMMU_PTE_SHIFT) & 0x3ff;
	u32 *count = page_address(as->count);
	u32 *pd = page_address(as->pd), *pt;
	struct page *page;

	page = pfn_to_page(pd[pde] & SMMU_PFN_MASK);
	pt = page_address(page);

	/*
	 * When no entries in this page table are used anymore, return the
	 * memory page to the system.
	 */
	if (pt[pte] != 0) {
		if (--count[pde] == 0) {
			ClearPageReserved(page);
			__free_page(page);
			pd[pde] = 0;
		}

		pt[pte] = 0;
	}
}

static int tegra_smmu_map(struct iommu_domain *domain, unsigned long iova,
			  phys_addr_t paddr, size_t size, int prot)
{
	struct tegra_smmu_as *as = domain->priv;
	struct tegra_smmu *smmu = as->smmu;
	unsigned long offset;
	struct page *page;
	u32 *pte;

	pte = as_get_pte(as, iova, &page);
	if (!pte)
		return -ENOMEM;

	*pte = __phys_to_pfn(paddr) | SMMU_PTE_ATTR;
	offset = offset_in_page(pte);

	smmu->soc->ops->flush_dcache(page, offset, 4);
	smmu_flush_ptc(smmu, page, offset);
	smmu_flush_tlb_group(smmu, as->id, iova);
	smmu_flush(smmu);

	return 0;
}

static size_t tegra_smmu_unmap(struct iommu_domain *domain, unsigned long iova,
			       size_t size)
{
	struct tegra_smmu_as *as = domain->priv;
	struct tegra_smmu *smmu = as->smmu;
	unsigned long offset;
	struct page *page;
	u32 *pte;

	pte = as_get_pte(as, iova, &page);
	if (!pte)
		return 0;

	offset = offset_in_page(pte);
	as_put_pte(as, iova);

	smmu->soc->ops->flush_dcache(page, offset, 4);
	smmu_flush_ptc(smmu, page, offset);
	smmu_flush_tlb_group(smmu, as->id, iova);
	smmu_flush(smmu);

	return size;
}

static phys_addr_t tegra_smmu_iova_to_phys(struct iommu_domain *domain,
					   dma_addr_t iova)
{
	struct tegra_smmu_as *as = domain->priv;
	struct page *page;
	unsigned long pfn;
	u32 *pte;

	pte = as_get_pte(as, iova, &page);
	pfn = *pte & SMMU_PFN_MASK;

	return PFN_PHYS(pfn);
}

static struct tegra_smmu *tegra_smmu_find(struct device_node *np)
{
	struct platform_device *pdev;
	struct tegra_mc *mc;

	pdev = of_find_device_by_node(np);
	if (!pdev)
		return NULL;

	mc = platform_get_drvdata(pdev);
	if (!mc)
		return NULL;

	return mc->smmu;
}

static int tegra_smmu_add_device(struct device *dev)
{
	struct device_node *np = dev->of_node;
	struct of_phandle_args args;
	unsigned int index = 0;

	while (of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
					  &args) == 0) {
		struct tegra_smmu *smmu;

		smmu = tegra_smmu_find(args.np);
		if (smmu) {
			/*
			 * Only a single IOMMU master interface is currently
			 * supported by the Linux kernel, so abort after the
			 * first match.
			 */
			dev->archdata.iommu = smmu;
			break;
		}

		index++;
	}

	return 0;
}

static void tegra_smmu_remove_device(struct device *dev)
{
	dev->archdata.iommu = NULL;
}

static const struct iommu_ops tegra_smmu_ops = {
	.capable = tegra_smmu_capable,
	.domain_init = tegra_smmu_domain_init,
	.domain_destroy = tegra_smmu_domain_destroy,
	.attach_dev = tegra_smmu_attach_dev,
	.detach_dev = tegra_smmu_detach_dev,
	.add_device = tegra_smmu_add_device,
	.remove_device = tegra_smmu_remove_device,
	.map = tegra_smmu_map,
	.unmap = tegra_smmu_unmap,
	.map_sg = default_iommu_map_sg,
	.iova_to_phys = tegra_smmu_iova_to_phys,

	.pgsize_bitmap = SZ_4K,
};

static void tegra_smmu_ahb_enable(void)
{
	static const struct of_device_id ahb_match[] = {
		{ .compatible = "nvidia,tegra30-ahb", },
		{ }
	};
	struct device_node *ahb;

	ahb = of_find_matching_node(NULL, ahb_match);
	if (ahb) {
		tegra_ahb_enable_smmu(ahb);
		of_node_put(ahb);
	}
}

struct tegra_smmu *tegra_smmu_probe(struct device *dev,
				    const struct tegra_smmu_soc *soc,
				    struct tegra_mc *mc)
{
	struct tegra_smmu *smmu;
	size_t size;
	u32 value;
	int err;

	/* This can happen on Tegra20 which doesn't have an SMMU */
	if (!soc)
		return NULL;

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

	/*
	 * This is a bit of a hack. Ideally we'd want to simply return this
	 * value. However the IOMMU registration process will attempt to add
	 * all devices to the IOMMU when bus_set_iommu() is called. In order
	 * not to rely on global variables to track the IOMMU instance, we
	 * set it here so that it can be looked up from the .add_device()
	 * callback via the IOMMU device's .drvdata field.
	 */
	mc->smmu = smmu;

	size = BITS_TO_LONGS(soc->num_asids) * sizeof(long);

	smmu->asids = devm_kzalloc(dev, size, GFP_KERNEL);
	if (!smmu->asids)
		return ERR_PTR(-ENOMEM);

	mutex_init(&smmu->lock);

	smmu->regs = mc->regs;
	smmu->soc = soc;
	smmu->dev = dev;
	smmu->mc = mc;

	value = SMMU_PTC_CONFIG_ENABLE | SMMU_PTC_CONFIG_INDEX_MAP(0x3f);

	if (soc->supports_request_limit)
		value |= SMMU_PTC_CONFIG_REQ_LIMIT(8);

	smmu_writel(smmu, value, SMMU_PTC_CONFIG);

	value = SMMU_TLB_CONFIG_HIT_UNDER_MISS |
		SMMU_TLB_CONFIG_ACTIVE_LINES(0x20);

	if (soc->supports_round_robin_arbitration)
		value |= SMMU_TLB_CONFIG_ROUND_ROBIN_ARBITRATION;

	smmu_writel(smmu, value, SMMU_TLB_CONFIG);

	smmu_flush_ptc(smmu, NULL, 0);
	smmu_flush_tlb(smmu);
	smmu_writel(smmu, SMMU_CONFIG_ENABLE, SMMU_CONFIG);
	smmu_flush(smmu);

	tegra_smmu_ahb_enable();

	err = bus_set_iommu(&platform_bus_type, &tegra_smmu_ops);
	if (err < 0)
		return ERR_PTR(err);

	return smmu;
}
OpenPOWER on IntegriCloud