xref: /openbmc/linux/drivers/iommu/omap-iommu.c (revision e6dec923)
1 /*
2  * omap iommu: tlb and pagetable primitives
3  *
4  * Copyright (C) 2008-2010 Nokia Corporation
5  *
6  * Written by Hiroshi DOYU <Hiroshi.DOYU@nokia.com>,
7  *		Paul Mundt and Toshihiro Kobayashi
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 
14 #include <linux/err.h>
15 #include <linux/slab.h>
16 #include <linux/interrupt.h>
17 #include <linux/ioport.h>
18 #include <linux/platform_device.h>
19 #include <linux/iommu.h>
20 #include <linux/omap-iommu.h>
21 #include <linux/mutex.h>
22 #include <linux/spinlock.h>
23 #include <linux/io.h>
24 #include <linux/pm_runtime.h>
25 #include <linux/of.h>
26 #include <linux/of_iommu.h>
27 #include <linux/of_irq.h>
28 #include <linux/of_platform.h>
29 #include <linux/regmap.h>
30 #include <linux/mfd/syscon.h>
31 
32 #include <asm/cacheflush.h>
33 
34 #include <linux/platform_data/iommu-omap.h>
35 
36 #include "omap-iopgtable.h"
37 #include "omap-iommu.h"
38 
39 static const struct iommu_ops omap_iommu_ops;
40 
41 #define to_iommu(dev)							\
42 	((struct omap_iommu *)platform_get_drvdata(to_platform_device(dev)))
43 
44 /* bitmap of the page sizes currently supported */
45 #define OMAP_IOMMU_PGSIZES	(SZ_4K | SZ_64K | SZ_1M | SZ_16M)
46 
47 #define MMU_LOCK_BASE_SHIFT	10
48 #define MMU_LOCK_BASE_MASK	(0x1f << MMU_LOCK_BASE_SHIFT)
49 #define MMU_LOCK_BASE(x)	\
50 	((x & MMU_LOCK_BASE_MASK) >> MMU_LOCK_BASE_SHIFT)
51 
52 #define MMU_LOCK_VICT_SHIFT	4
53 #define MMU_LOCK_VICT_MASK	(0x1f << MMU_LOCK_VICT_SHIFT)
54 #define MMU_LOCK_VICT(x)	\
55 	((x & MMU_LOCK_VICT_MASK) >> MMU_LOCK_VICT_SHIFT)
56 
57 static struct platform_driver omap_iommu_driver;
58 static struct kmem_cache *iopte_cachep;
59 
60 /**
61  * to_omap_domain - Get struct omap_iommu_domain from generic iommu_domain
62  * @dom:	generic iommu domain handle
63  **/
64 static struct omap_iommu_domain *to_omap_domain(struct iommu_domain *dom)
65 {
66 	return container_of(dom, struct omap_iommu_domain, domain);
67 }
68 
69 /**
70  * omap_iommu_save_ctx - Save registers for pm off-mode support
71  * @dev:	client device
72  **/
73 void omap_iommu_save_ctx(struct device *dev)
74 {
75 	struct omap_iommu *obj = dev_to_omap_iommu(dev);
76 	u32 *p = obj->ctx;
77 	int i;
78 
79 	for (i = 0; i < (MMU_REG_SIZE / sizeof(u32)); i++) {
80 		p[i] = iommu_read_reg(obj, i * sizeof(u32));
81 		dev_dbg(obj->dev, "%s\t[%02d] %08x\n", __func__, i, p[i]);
82 	}
83 }
84 EXPORT_SYMBOL_GPL(omap_iommu_save_ctx);
85 
86 /**
87  * omap_iommu_restore_ctx - Restore registers for pm off-mode support
88  * @dev:	client device
89  **/
90 void omap_iommu_restore_ctx(struct device *dev)
91 {
92 	struct omap_iommu *obj = dev_to_omap_iommu(dev);
93 	u32 *p = obj->ctx;
94 	int i;
95 
96 	for (i = 0; i < (MMU_REG_SIZE / sizeof(u32)); i++) {
97 		iommu_write_reg(obj, p[i], i * sizeof(u32));
98 		dev_dbg(obj->dev, "%s\t[%02d] %08x\n", __func__, i, p[i]);
99 	}
100 }
101 EXPORT_SYMBOL_GPL(omap_iommu_restore_ctx);
102 
103 static void dra7_cfg_dspsys_mmu(struct omap_iommu *obj, bool enable)
104 {
105 	u32 val, mask;
106 
107 	if (!obj->syscfg)
108 		return;
109 
110 	mask = (1 << (obj->id * DSP_SYS_MMU_CONFIG_EN_SHIFT));
111 	val = enable ? mask : 0;
112 	regmap_update_bits(obj->syscfg, DSP_SYS_MMU_CONFIG, mask, val);
113 }
114 
115 static void __iommu_set_twl(struct omap_iommu *obj, bool on)
116 {
117 	u32 l = iommu_read_reg(obj, MMU_CNTL);
118 
119 	if (on)
120 		iommu_write_reg(obj, MMU_IRQ_TWL_MASK, MMU_IRQENABLE);
121 	else
122 		iommu_write_reg(obj, MMU_IRQ_TLB_MISS_MASK, MMU_IRQENABLE);
123 
124 	l &= ~MMU_CNTL_MASK;
125 	if (on)
126 		l |= (MMU_CNTL_MMU_EN | MMU_CNTL_TWL_EN);
127 	else
128 		l |= (MMU_CNTL_MMU_EN);
129 
130 	iommu_write_reg(obj, l, MMU_CNTL);
131 }
132 
133 static int omap2_iommu_enable(struct omap_iommu *obj)
134 {
135 	u32 l, pa;
136 
137 	if (!obj->iopgd || !IS_ALIGNED((u32)obj->iopgd,  SZ_16K))
138 		return -EINVAL;
139 
140 	pa = virt_to_phys(obj->iopgd);
141 	if (!IS_ALIGNED(pa, SZ_16K))
142 		return -EINVAL;
143 
144 	l = iommu_read_reg(obj, MMU_REVISION);
145 	dev_info(obj->dev, "%s: version %d.%d\n", obj->name,
146 		 (l >> 4) & 0xf, l & 0xf);
147 
148 	iommu_write_reg(obj, pa, MMU_TTB);
149 
150 	dra7_cfg_dspsys_mmu(obj, true);
151 
152 	if (obj->has_bus_err_back)
153 		iommu_write_reg(obj, MMU_GP_REG_BUS_ERR_BACK_EN, MMU_GP_REG);
154 
155 	__iommu_set_twl(obj, true);
156 
157 	return 0;
158 }
159 
160 static void omap2_iommu_disable(struct omap_iommu *obj)
161 {
162 	u32 l = iommu_read_reg(obj, MMU_CNTL);
163 
164 	l &= ~MMU_CNTL_MASK;
165 	iommu_write_reg(obj, l, MMU_CNTL);
166 	dra7_cfg_dspsys_mmu(obj, false);
167 
168 	dev_dbg(obj->dev, "%s is shutting down\n", obj->name);
169 }
170 
171 static int iommu_enable(struct omap_iommu *obj)
172 {
173 	int err;
174 	struct platform_device *pdev = to_platform_device(obj->dev);
175 	struct iommu_platform_data *pdata = dev_get_platdata(&pdev->dev);
176 
177 	if (pdata && pdata->deassert_reset) {
178 		err = pdata->deassert_reset(pdev, pdata->reset_name);
179 		if (err) {
180 			dev_err(obj->dev, "deassert_reset failed: %d\n", err);
181 			return err;
182 		}
183 	}
184 
185 	pm_runtime_get_sync(obj->dev);
186 
187 	err = omap2_iommu_enable(obj);
188 
189 	return err;
190 }
191 
192 static void iommu_disable(struct omap_iommu *obj)
193 {
194 	struct platform_device *pdev = to_platform_device(obj->dev);
195 	struct iommu_platform_data *pdata = dev_get_platdata(&pdev->dev);
196 
197 	omap2_iommu_disable(obj);
198 
199 	pm_runtime_put_sync(obj->dev);
200 
201 	if (pdata && pdata->assert_reset)
202 		pdata->assert_reset(pdev, pdata->reset_name);
203 }
204 
205 /*
206  *	TLB operations
207  */
208 static u32 iotlb_cr_to_virt(struct cr_regs *cr)
209 {
210 	u32 page_size = cr->cam & MMU_CAM_PGSZ_MASK;
211 	u32 mask = get_cam_va_mask(cr->cam & page_size);
212 
213 	return cr->cam & mask;
214 }
215 
216 static u32 get_iopte_attr(struct iotlb_entry *e)
217 {
218 	u32 attr;
219 
220 	attr = e->mixed << 5;
221 	attr |= e->endian;
222 	attr |= e->elsz >> 3;
223 	attr <<= (((e->pgsz == MMU_CAM_PGSZ_4K) ||
224 			(e->pgsz == MMU_CAM_PGSZ_64K)) ? 0 : 6);
225 	return attr;
226 }
227 
228 static u32 iommu_report_fault(struct omap_iommu *obj, u32 *da)
229 {
230 	u32 status, fault_addr;
231 
232 	status = iommu_read_reg(obj, MMU_IRQSTATUS);
233 	status &= MMU_IRQ_MASK;
234 	if (!status) {
235 		*da = 0;
236 		return 0;
237 	}
238 
239 	fault_addr = iommu_read_reg(obj, MMU_FAULT_AD);
240 	*da = fault_addr;
241 
242 	iommu_write_reg(obj, status, MMU_IRQSTATUS);
243 
244 	return status;
245 }
246 
247 void iotlb_lock_get(struct omap_iommu *obj, struct iotlb_lock *l)
248 {
249 	u32 val;
250 
251 	val = iommu_read_reg(obj, MMU_LOCK);
252 
253 	l->base = MMU_LOCK_BASE(val);
254 	l->vict = MMU_LOCK_VICT(val);
255 }
256 
257 void iotlb_lock_set(struct omap_iommu *obj, struct iotlb_lock *l)
258 {
259 	u32 val;
260 
261 	val = (l->base << MMU_LOCK_BASE_SHIFT);
262 	val |= (l->vict << MMU_LOCK_VICT_SHIFT);
263 
264 	iommu_write_reg(obj, val, MMU_LOCK);
265 }
266 
267 static void iotlb_read_cr(struct omap_iommu *obj, struct cr_regs *cr)
268 {
269 	cr->cam = iommu_read_reg(obj, MMU_READ_CAM);
270 	cr->ram = iommu_read_reg(obj, MMU_READ_RAM);
271 }
272 
273 static void iotlb_load_cr(struct omap_iommu *obj, struct cr_regs *cr)
274 {
275 	iommu_write_reg(obj, cr->cam | MMU_CAM_V, MMU_CAM);
276 	iommu_write_reg(obj, cr->ram, MMU_RAM);
277 
278 	iommu_write_reg(obj, 1, MMU_FLUSH_ENTRY);
279 	iommu_write_reg(obj, 1, MMU_LD_TLB);
280 }
281 
282 /* only used in iotlb iteration for-loop */
283 struct cr_regs __iotlb_read_cr(struct omap_iommu *obj, int n)
284 {
285 	struct cr_regs cr;
286 	struct iotlb_lock l;
287 
288 	iotlb_lock_get(obj, &l);
289 	l.vict = n;
290 	iotlb_lock_set(obj, &l);
291 	iotlb_read_cr(obj, &cr);
292 
293 	return cr;
294 }
295 
296 #ifdef PREFETCH_IOTLB
297 static struct cr_regs *iotlb_alloc_cr(struct omap_iommu *obj,
298 				      struct iotlb_entry *e)
299 {
300 	struct cr_regs *cr;
301 
302 	if (!e)
303 		return NULL;
304 
305 	if (e->da & ~(get_cam_va_mask(e->pgsz))) {
306 		dev_err(obj->dev, "%s:\twrong alignment: %08x\n", __func__,
307 			e->da);
308 		return ERR_PTR(-EINVAL);
309 	}
310 
311 	cr = kmalloc(sizeof(*cr), GFP_KERNEL);
312 	if (!cr)
313 		return ERR_PTR(-ENOMEM);
314 
315 	cr->cam = (e->da & MMU_CAM_VATAG_MASK) | e->prsvd | e->pgsz | e->valid;
316 	cr->ram = e->pa | e->endian | e->elsz | e->mixed;
317 
318 	return cr;
319 }
320 
321 /**
322  * load_iotlb_entry - Set an iommu tlb entry
323  * @obj:	target iommu
324  * @e:		an iommu tlb entry info
325  **/
326 static int load_iotlb_entry(struct omap_iommu *obj, struct iotlb_entry *e)
327 {
328 	int err = 0;
329 	struct iotlb_lock l;
330 	struct cr_regs *cr;
331 
332 	if (!obj || !obj->nr_tlb_entries || !e)
333 		return -EINVAL;
334 
335 	pm_runtime_get_sync(obj->dev);
336 
337 	iotlb_lock_get(obj, &l);
338 	if (l.base == obj->nr_tlb_entries) {
339 		dev_warn(obj->dev, "%s: preserve entries full\n", __func__);
340 		err = -EBUSY;
341 		goto out;
342 	}
343 	if (!e->prsvd) {
344 		int i;
345 		struct cr_regs tmp;
346 
347 		for_each_iotlb_cr(obj, obj->nr_tlb_entries, i, tmp)
348 			if (!iotlb_cr_valid(&tmp))
349 				break;
350 
351 		if (i == obj->nr_tlb_entries) {
352 			dev_dbg(obj->dev, "%s: full: no entry\n", __func__);
353 			err = -EBUSY;
354 			goto out;
355 		}
356 
357 		iotlb_lock_get(obj, &l);
358 	} else {
359 		l.vict = l.base;
360 		iotlb_lock_set(obj, &l);
361 	}
362 
363 	cr = iotlb_alloc_cr(obj, e);
364 	if (IS_ERR(cr)) {
365 		pm_runtime_put_sync(obj->dev);
366 		return PTR_ERR(cr);
367 	}
368 
369 	iotlb_load_cr(obj, cr);
370 	kfree(cr);
371 
372 	if (e->prsvd)
373 		l.base++;
374 	/* increment victim for next tlb load */
375 	if (++l.vict == obj->nr_tlb_entries)
376 		l.vict = l.base;
377 	iotlb_lock_set(obj, &l);
378 out:
379 	pm_runtime_put_sync(obj->dev);
380 	return err;
381 }
382 
383 #else /* !PREFETCH_IOTLB */
384 
385 static int load_iotlb_entry(struct omap_iommu *obj, struct iotlb_entry *e)
386 {
387 	return 0;
388 }
389 
390 #endif /* !PREFETCH_IOTLB */
391 
392 static int prefetch_iotlb_entry(struct omap_iommu *obj, struct iotlb_entry *e)
393 {
394 	return load_iotlb_entry(obj, e);
395 }
396 
397 /**
398  * flush_iotlb_page - Clear an iommu tlb entry
399  * @obj:	target iommu
400  * @da:		iommu device virtual address
401  *
402  * Clear an iommu tlb entry which includes 'da' address.
403  **/
404 static void flush_iotlb_page(struct omap_iommu *obj, u32 da)
405 {
406 	int i;
407 	struct cr_regs cr;
408 
409 	pm_runtime_get_sync(obj->dev);
410 
411 	for_each_iotlb_cr(obj, obj->nr_tlb_entries, i, cr) {
412 		u32 start;
413 		size_t bytes;
414 
415 		if (!iotlb_cr_valid(&cr))
416 			continue;
417 
418 		start = iotlb_cr_to_virt(&cr);
419 		bytes = iopgsz_to_bytes(cr.cam & 3);
420 
421 		if ((start <= da) && (da < start + bytes)) {
422 			dev_dbg(obj->dev, "%s: %08x<=%08x(%x)\n",
423 				__func__, start, da, bytes);
424 			iotlb_load_cr(obj, &cr);
425 			iommu_write_reg(obj, 1, MMU_FLUSH_ENTRY);
426 			break;
427 		}
428 	}
429 	pm_runtime_put_sync(obj->dev);
430 
431 	if (i == obj->nr_tlb_entries)
432 		dev_dbg(obj->dev, "%s: no page for %08x\n", __func__, da);
433 }
434 
435 /**
436  * flush_iotlb_all - Clear all iommu tlb entries
437  * @obj:	target iommu
438  **/
439 static void flush_iotlb_all(struct omap_iommu *obj)
440 {
441 	struct iotlb_lock l;
442 
443 	pm_runtime_get_sync(obj->dev);
444 
445 	l.base = 0;
446 	l.vict = 0;
447 	iotlb_lock_set(obj, &l);
448 
449 	iommu_write_reg(obj, 1, MMU_GFLUSH);
450 
451 	pm_runtime_put_sync(obj->dev);
452 }
453 
454 /*
455  *	H/W pagetable operations
456  */
457 static void flush_iopgd_range(u32 *first, u32 *last)
458 {
459 	/* FIXME: L2 cache should be taken care of if it exists */
460 	do {
461 		asm("mcr	p15, 0, %0, c7, c10, 1 @ flush_pgd"
462 		    : : "r" (first));
463 		first += L1_CACHE_BYTES / sizeof(*first);
464 	} while (first <= last);
465 }
466 
467 static void flush_iopte_range(u32 *first, u32 *last)
468 {
469 	/* FIXME: L2 cache should be taken care of if it exists */
470 	do {
471 		asm("mcr	p15, 0, %0, c7, c10, 1 @ flush_pte"
472 		    : : "r" (first));
473 		first += L1_CACHE_BYTES / sizeof(*first);
474 	} while (first <= last);
475 }
476 
477 static void iopte_free(u32 *iopte)
478 {
479 	/* Note: freed iopte's must be clean ready for re-use */
480 	if (iopte)
481 		kmem_cache_free(iopte_cachep, iopte);
482 }
483 
484 static u32 *iopte_alloc(struct omap_iommu *obj, u32 *iopgd, u32 da)
485 {
486 	u32 *iopte;
487 
488 	/* a table has already existed */
489 	if (*iopgd)
490 		goto pte_ready;
491 
492 	/*
493 	 * do the allocation outside the page table lock
494 	 */
495 	spin_unlock(&obj->page_table_lock);
496 	iopte = kmem_cache_zalloc(iopte_cachep, GFP_KERNEL);
497 	spin_lock(&obj->page_table_lock);
498 
499 	if (!*iopgd) {
500 		if (!iopte)
501 			return ERR_PTR(-ENOMEM);
502 
503 		*iopgd = virt_to_phys(iopte) | IOPGD_TABLE;
504 		flush_iopgd_range(iopgd, iopgd);
505 
506 		dev_vdbg(obj->dev, "%s: a new pte:%p\n", __func__, iopte);
507 	} else {
508 		/* We raced, free the reduniovant table */
509 		iopte_free(iopte);
510 	}
511 
512 pte_ready:
513 	iopte = iopte_offset(iopgd, da);
514 
515 	dev_vdbg(obj->dev,
516 		 "%s: da:%08x pgd:%p *pgd:%08x pte:%p *pte:%08x\n",
517 		 __func__, da, iopgd, *iopgd, iopte, *iopte);
518 
519 	return iopte;
520 }
521 
522 static int iopgd_alloc_section(struct omap_iommu *obj, u32 da, u32 pa, u32 prot)
523 {
524 	u32 *iopgd = iopgd_offset(obj, da);
525 
526 	if ((da | pa) & ~IOSECTION_MASK) {
527 		dev_err(obj->dev, "%s: %08x:%08x should aligned on %08lx\n",
528 			__func__, da, pa, IOSECTION_SIZE);
529 		return -EINVAL;
530 	}
531 
532 	*iopgd = (pa & IOSECTION_MASK) | prot | IOPGD_SECTION;
533 	flush_iopgd_range(iopgd, iopgd);
534 	return 0;
535 }
536 
537 static int iopgd_alloc_super(struct omap_iommu *obj, u32 da, u32 pa, u32 prot)
538 {
539 	u32 *iopgd = iopgd_offset(obj, da);
540 	int i;
541 
542 	if ((da | pa) & ~IOSUPER_MASK) {
543 		dev_err(obj->dev, "%s: %08x:%08x should aligned on %08lx\n",
544 			__func__, da, pa, IOSUPER_SIZE);
545 		return -EINVAL;
546 	}
547 
548 	for (i = 0; i < 16; i++)
549 		*(iopgd + i) = (pa & IOSUPER_MASK) | prot | IOPGD_SUPER;
550 	flush_iopgd_range(iopgd, iopgd + 15);
551 	return 0;
552 }
553 
554 static int iopte_alloc_page(struct omap_iommu *obj, u32 da, u32 pa, u32 prot)
555 {
556 	u32 *iopgd = iopgd_offset(obj, da);
557 	u32 *iopte = iopte_alloc(obj, iopgd, da);
558 
559 	if (IS_ERR(iopte))
560 		return PTR_ERR(iopte);
561 
562 	*iopte = (pa & IOPAGE_MASK) | prot | IOPTE_SMALL;
563 	flush_iopte_range(iopte, iopte);
564 
565 	dev_vdbg(obj->dev, "%s: da:%08x pa:%08x pte:%p *pte:%08x\n",
566 		 __func__, da, pa, iopte, *iopte);
567 
568 	return 0;
569 }
570 
571 static int iopte_alloc_large(struct omap_iommu *obj, u32 da, u32 pa, u32 prot)
572 {
573 	u32 *iopgd = iopgd_offset(obj, da);
574 	u32 *iopte = iopte_alloc(obj, iopgd, da);
575 	int i;
576 
577 	if ((da | pa) & ~IOLARGE_MASK) {
578 		dev_err(obj->dev, "%s: %08x:%08x should aligned on %08lx\n",
579 			__func__, da, pa, IOLARGE_SIZE);
580 		return -EINVAL;
581 	}
582 
583 	if (IS_ERR(iopte))
584 		return PTR_ERR(iopte);
585 
586 	for (i = 0; i < 16; i++)
587 		*(iopte + i) = (pa & IOLARGE_MASK) | prot | IOPTE_LARGE;
588 	flush_iopte_range(iopte, iopte + 15);
589 	return 0;
590 }
591 
592 static int
593 iopgtable_store_entry_core(struct omap_iommu *obj, struct iotlb_entry *e)
594 {
595 	int (*fn)(struct omap_iommu *, u32, u32, u32);
596 	u32 prot;
597 	int err;
598 
599 	if (!obj || !e)
600 		return -EINVAL;
601 
602 	switch (e->pgsz) {
603 	case MMU_CAM_PGSZ_16M:
604 		fn = iopgd_alloc_super;
605 		break;
606 	case MMU_CAM_PGSZ_1M:
607 		fn = iopgd_alloc_section;
608 		break;
609 	case MMU_CAM_PGSZ_64K:
610 		fn = iopte_alloc_large;
611 		break;
612 	case MMU_CAM_PGSZ_4K:
613 		fn = iopte_alloc_page;
614 		break;
615 	default:
616 		fn = NULL;
617 		break;
618 	}
619 
620 	if (WARN_ON(!fn))
621 		return -EINVAL;
622 
623 	prot = get_iopte_attr(e);
624 
625 	spin_lock(&obj->page_table_lock);
626 	err = fn(obj, e->da, e->pa, prot);
627 	spin_unlock(&obj->page_table_lock);
628 
629 	return err;
630 }
631 
632 /**
633  * omap_iopgtable_store_entry - Make an iommu pte entry
634  * @obj:	target iommu
635  * @e:		an iommu tlb entry info
636  **/
637 static int
638 omap_iopgtable_store_entry(struct omap_iommu *obj, struct iotlb_entry *e)
639 {
640 	int err;
641 
642 	flush_iotlb_page(obj, e->da);
643 	err = iopgtable_store_entry_core(obj, e);
644 	if (!err)
645 		prefetch_iotlb_entry(obj, e);
646 	return err;
647 }
648 
649 /**
650  * iopgtable_lookup_entry - Lookup an iommu pte entry
651  * @obj:	target iommu
652  * @da:		iommu device virtual address
653  * @ppgd:	iommu pgd entry pointer to be returned
654  * @ppte:	iommu pte entry pointer to be returned
655  **/
656 static void
657 iopgtable_lookup_entry(struct omap_iommu *obj, u32 da, u32 **ppgd, u32 **ppte)
658 {
659 	u32 *iopgd, *iopte = NULL;
660 
661 	iopgd = iopgd_offset(obj, da);
662 	if (!*iopgd)
663 		goto out;
664 
665 	if (iopgd_is_table(*iopgd))
666 		iopte = iopte_offset(iopgd, da);
667 out:
668 	*ppgd = iopgd;
669 	*ppte = iopte;
670 }
671 
672 static size_t iopgtable_clear_entry_core(struct omap_iommu *obj, u32 da)
673 {
674 	size_t bytes;
675 	u32 *iopgd = iopgd_offset(obj, da);
676 	int nent = 1;
677 
678 	if (!*iopgd)
679 		return 0;
680 
681 	if (iopgd_is_table(*iopgd)) {
682 		int i;
683 		u32 *iopte = iopte_offset(iopgd, da);
684 
685 		bytes = IOPTE_SIZE;
686 		if (*iopte & IOPTE_LARGE) {
687 			nent *= 16;
688 			/* rewind to the 1st entry */
689 			iopte = iopte_offset(iopgd, (da & IOLARGE_MASK));
690 		}
691 		bytes *= nent;
692 		memset(iopte, 0, nent * sizeof(*iopte));
693 		flush_iopte_range(iopte, iopte + (nent - 1) * sizeof(*iopte));
694 
695 		/*
696 		 * do table walk to check if this table is necessary or not
697 		 */
698 		iopte = iopte_offset(iopgd, 0);
699 		for (i = 0; i < PTRS_PER_IOPTE; i++)
700 			if (iopte[i])
701 				goto out;
702 
703 		iopte_free(iopte);
704 		nent = 1; /* for the next L1 entry */
705 	} else {
706 		bytes = IOPGD_SIZE;
707 		if ((*iopgd & IOPGD_SUPER) == IOPGD_SUPER) {
708 			nent *= 16;
709 			/* rewind to the 1st entry */
710 			iopgd = iopgd_offset(obj, (da & IOSUPER_MASK));
711 		}
712 		bytes *= nent;
713 	}
714 	memset(iopgd, 0, nent * sizeof(*iopgd));
715 	flush_iopgd_range(iopgd, iopgd + (nent - 1) * sizeof(*iopgd));
716 out:
717 	return bytes;
718 }
719 
720 /**
721  * iopgtable_clear_entry - Remove an iommu pte entry
722  * @obj:	target iommu
723  * @da:		iommu device virtual address
724  **/
725 static size_t iopgtable_clear_entry(struct omap_iommu *obj, u32 da)
726 {
727 	size_t bytes;
728 
729 	spin_lock(&obj->page_table_lock);
730 
731 	bytes = iopgtable_clear_entry_core(obj, da);
732 	flush_iotlb_page(obj, da);
733 
734 	spin_unlock(&obj->page_table_lock);
735 
736 	return bytes;
737 }
738 
739 static void iopgtable_clear_entry_all(struct omap_iommu *obj)
740 {
741 	int i;
742 
743 	spin_lock(&obj->page_table_lock);
744 
745 	for (i = 0; i < PTRS_PER_IOPGD; i++) {
746 		u32 da;
747 		u32 *iopgd;
748 
749 		da = i << IOPGD_SHIFT;
750 		iopgd = iopgd_offset(obj, da);
751 
752 		if (!*iopgd)
753 			continue;
754 
755 		if (iopgd_is_table(*iopgd))
756 			iopte_free(iopte_offset(iopgd, 0));
757 
758 		*iopgd = 0;
759 		flush_iopgd_range(iopgd, iopgd);
760 	}
761 
762 	flush_iotlb_all(obj);
763 
764 	spin_unlock(&obj->page_table_lock);
765 }
766 
767 /*
768  *	Device IOMMU generic operations
769  */
770 static irqreturn_t iommu_fault_handler(int irq, void *data)
771 {
772 	u32 da, errs;
773 	u32 *iopgd, *iopte;
774 	struct omap_iommu *obj = data;
775 	struct iommu_domain *domain = obj->domain;
776 	struct omap_iommu_domain *omap_domain = to_omap_domain(domain);
777 
778 	if (!omap_domain->iommu_dev)
779 		return IRQ_NONE;
780 
781 	errs = iommu_report_fault(obj, &da);
782 	if (errs == 0)
783 		return IRQ_HANDLED;
784 
785 	/* Fault callback or TLB/PTE Dynamic loading */
786 	if (!report_iommu_fault(domain, obj->dev, da, 0))
787 		return IRQ_HANDLED;
788 
789 	iommu_disable(obj);
790 
791 	iopgd = iopgd_offset(obj, da);
792 
793 	if (!iopgd_is_table(*iopgd)) {
794 		dev_err(obj->dev, "%s: errs:0x%08x da:0x%08x pgd:0x%p *pgd:px%08x\n",
795 			obj->name, errs, da, iopgd, *iopgd);
796 		return IRQ_NONE;
797 	}
798 
799 	iopte = iopte_offset(iopgd, da);
800 
801 	dev_err(obj->dev, "%s: errs:0x%08x da:0x%08x pgd:0x%p *pgd:0x%08x pte:0x%p *pte:0x%08x\n",
802 		obj->name, errs, da, iopgd, *iopgd, iopte, *iopte);
803 
804 	return IRQ_NONE;
805 }
806 
807 /**
808  * omap_iommu_attach() - attach iommu device to an iommu domain
809  * @obj:	target omap iommu device
810  * @iopgd:	page table
811  **/
812 static int omap_iommu_attach(struct omap_iommu *obj, u32 *iopgd)
813 {
814 	int err;
815 
816 	spin_lock(&obj->iommu_lock);
817 
818 	obj->iopgd = iopgd;
819 	err = iommu_enable(obj);
820 	if (err)
821 		goto err_enable;
822 	flush_iotlb_all(obj);
823 
824 	spin_unlock(&obj->iommu_lock);
825 
826 	dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
827 
828 	return 0;
829 
830 err_enable:
831 	spin_unlock(&obj->iommu_lock);
832 
833 	return err;
834 }
835 
836 /**
837  * omap_iommu_detach - release iommu device
838  * @obj:	target iommu
839  **/
840 static void omap_iommu_detach(struct omap_iommu *obj)
841 {
842 	if (!obj || IS_ERR(obj))
843 		return;
844 
845 	spin_lock(&obj->iommu_lock);
846 
847 	iommu_disable(obj);
848 	obj->iopgd = NULL;
849 
850 	spin_unlock(&obj->iommu_lock);
851 
852 	dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
853 }
854 
855 static int omap_iommu_dra7_get_dsp_system_cfg(struct platform_device *pdev,
856 					      struct omap_iommu *obj)
857 {
858 	struct device_node *np = pdev->dev.of_node;
859 	int ret;
860 
861 	if (!of_device_is_compatible(np, "ti,dra7-dsp-iommu"))
862 		return 0;
863 
864 	if (!of_property_read_bool(np, "ti,syscon-mmuconfig")) {
865 		dev_err(&pdev->dev, "ti,syscon-mmuconfig property is missing\n");
866 		return -EINVAL;
867 	}
868 
869 	obj->syscfg =
870 		syscon_regmap_lookup_by_phandle(np, "ti,syscon-mmuconfig");
871 	if (IS_ERR(obj->syscfg)) {
872 		/* can fail with -EPROBE_DEFER */
873 		ret = PTR_ERR(obj->syscfg);
874 		return ret;
875 	}
876 
877 	if (of_property_read_u32_index(np, "ti,syscon-mmuconfig", 1,
878 				       &obj->id)) {
879 		dev_err(&pdev->dev, "couldn't get the IOMMU instance id within subsystem\n");
880 		return -EINVAL;
881 	}
882 
883 	if (obj->id != 0 && obj->id != 1) {
884 		dev_err(&pdev->dev, "invalid IOMMU instance id\n");
885 		return -EINVAL;
886 	}
887 
888 	return 0;
889 }
890 
891 /*
892  *	OMAP Device MMU(IOMMU) detection
893  */
894 static int omap_iommu_probe(struct platform_device *pdev)
895 {
896 	int err = -ENODEV;
897 	int irq;
898 	struct omap_iommu *obj;
899 	struct resource *res;
900 	struct device_node *of = pdev->dev.of_node;
901 
902 	if (!of) {
903 		pr_err("%s: only DT-based devices are supported\n", __func__);
904 		return -ENODEV;
905 	}
906 
907 	obj = devm_kzalloc(&pdev->dev, sizeof(*obj) + MMU_REG_SIZE, GFP_KERNEL);
908 	if (!obj)
909 		return -ENOMEM;
910 
911 	obj->name = dev_name(&pdev->dev);
912 	obj->nr_tlb_entries = 32;
913 	err = of_property_read_u32(of, "ti,#tlb-entries", &obj->nr_tlb_entries);
914 	if (err && err != -EINVAL)
915 		return err;
916 	if (obj->nr_tlb_entries != 32 && obj->nr_tlb_entries != 8)
917 		return -EINVAL;
918 	if (of_find_property(of, "ti,iommu-bus-err-back", NULL))
919 		obj->has_bus_err_back = MMU_GP_REG_BUS_ERR_BACK_EN;
920 
921 	obj->dev = &pdev->dev;
922 	obj->ctx = (void *)obj + sizeof(*obj);
923 
924 	spin_lock_init(&obj->iommu_lock);
925 	spin_lock_init(&obj->page_table_lock);
926 
927 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
928 	obj->regbase = devm_ioremap_resource(obj->dev, res);
929 	if (IS_ERR(obj->regbase))
930 		return PTR_ERR(obj->regbase);
931 
932 	err = omap_iommu_dra7_get_dsp_system_cfg(pdev, obj);
933 	if (err)
934 		return err;
935 
936 	irq = platform_get_irq(pdev, 0);
937 	if (irq < 0)
938 		return -ENODEV;
939 
940 	err = devm_request_irq(obj->dev, irq, iommu_fault_handler, IRQF_SHARED,
941 			       dev_name(obj->dev), obj);
942 	if (err < 0)
943 		return err;
944 	platform_set_drvdata(pdev, obj);
945 
946 	obj->group = iommu_group_alloc();
947 	if (IS_ERR(obj->group))
948 		return PTR_ERR(obj->group);
949 
950 	err = iommu_device_sysfs_add(&obj->iommu, obj->dev, NULL, obj->name);
951 	if (err)
952 		goto out_group;
953 
954 	iommu_device_set_ops(&obj->iommu, &omap_iommu_ops);
955 
956 	err = iommu_device_register(&obj->iommu);
957 	if (err)
958 		goto out_sysfs;
959 
960 	pm_runtime_irq_safe(obj->dev);
961 	pm_runtime_enable(obj->dev);
962 
963 	omap_iommu_debugfs_add(obj);
964 
965 	dev_info(&pdev->dev, "%s registered\n", obj->name);
966 
967 	return 0;
968 
969 out_sysfs:
970 	iommu_device_sysfs_remove(&obj->iommu);
971 out_group:
972 	iommu_group_put(obj->group);
973 	return err;
974 }
975 
976 static int omap_iommu_remove(struct platform_device *pdev)
977 {
978 	struct omap_iommu *obj = platform_get_drvdata(pdev);
979 
980 	iommu_group_put(obj->group);
981 	obj->group = NULL;
982 
983 	iommu_device_sysfs_remove(&obj->iommu);
984 	iommu_device_unregister(&obj->iommu);
985 
986 	omap_iommu_debugfs_remove(obj);
987 
988 	pm_runtime_disable(obj->dev);
989 
990 	dev_info(&pdev->dev, "%s removed\n", obj->name);
991 	return 0;
992 }
993 
994 static const struct of_device_id omap_iommu_of_match[] = {
995 	{ .compatible = "ti,omap2-iommu" },
996 	{ .compatible = "ti,omap4-iommu" },
997 	{ .compatible = "ti,dra7-iommu"	},
998 	{ .compatible = "ti,dra7-dsp-iommu" },
999 	{},
1000 };
1001 
1002 static struct platform_driver omap_iommu_driver = {
1003 	.probe	= omap_iommu_probe,
1004 	.remove	= omap_iommu_remove,
1005 	.driver	= {
1006 		.name	= "omap-iommu",
1007 		.of_match_table = of_match_ptr(omap_iommu_of_match),
1008 	},
1009 };
1010 
1011 static void iopte_cachep_ctor(void *iopte)
1012 {
1013 	clean_dcache_area(iopte, IOPTE_TABLE_SIZE);
1014 }
1015 
1016 static u32 iotlb_init_entry(struct iotlb_entry *e, u32 da, u32 pa, int pgsz)
1017 {
1018 	memset(e, 0, sizeof(*e));
1019 
1020 	e->da		= da;
1021 	e->pa		= pa;
1022 	e->valid	= MMU_CAM_V;
1023 	e->pgsz		= pgsz;
1024 	e->endian	= MMU_RAM_ENDIAN_LITTLE;
1025 	e->elsz		= MMU_RAM_ELSZ_8;
1026 	e->mixed	= 0;
1027 
1028 	return iopgsz_to_bytes(e->pgsz);
1029 }
1030 
1031 static int omap_iommu_map(struct iommu_domain *domain, unsigned long da,
1032 			  phys_addr_t pa, size_t bytes, int prot)
1033 {
1034 	struct omap_iommu_domain *omap_domain = to_omap_domain(domain);
1035 	struct omap_iommu *oiommu = omap_domain->iommu_dev;
1036 	struct device *dev = oiommu->dev;
1037 	struct iotlb_entry e;
1038 	int omap_pgsz;
1039 	u32 ret;
1040 
1041 	omap_pgsz = bytes_to_iopgsz(bytes);
1042 	if (omap_pgsz < 0) {
1043 		dev_err(dev, "invalid size to map: %d\n", bytes);
1044 		return -EINVAL;
1045 	}
1046 
1047 	dev_dbg(dev, "mapping da 0x%lx to pa %pa size 0x%x\n", da, &pa, bytes);
1048 
1049 	iotlb_init_entry(&e, da, pa, omap_pgsz);
1050 
1051 	ret = omap_iopgtable_store_entry(oiommu, &e);
1052 	if (ret)
1053 		dev_err(dev, "omap_iopgtable_store_entry failed: %d\n", ret);
1054 
1055 	return ret;
1056 }
1057 
1058 static size_t omap_iommu_unmap(struct iommu_domain *domain, unsigned long da,
1059 			       size_t size)
1060 {
1061 	struct omap_iommu_domain *omap_domain = to_omap_domain(domain);
1062 	struct omap_iommu *oiommu = omap_domain->iommu_dev;
1063 	struct device *dev = oiommu->dev;
1064 
1065 	dev_dbg(dev, "unmapping da 0x%lx size %u\n", da, size);
1066 
1067 	return iopgtable_clear_entry(oiommu, da);
1068 }
1069 
1070 static int
1071 omap_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
1072 {
1073 	struct omap_iommu_domain *omap_domain = to_omap_domain(domain);
1074 	struct omap_iommu_arch_data *arch_data = dev->archdata.iommu;
1075 	struct omap_iommu *oiommu;
1076 	int ret = 0;
1077 
1078 	if (!arch_data || !arch_data->iommu_dev) {
1079 		dev_err(dev, "device doesn't have an associated iommu\n");
1080 		return -EINVAL;
1081 	}
1082 
1083 	spin_lock(&omap_domain->lock);
1084 
1085 	/* only a single device is supported per domain for now */
1086 	if (omap_domain->iommu_dev) {
1087 		dev_err(dev, "iommu domain is already attached\n");
1088 		ret = -EBUSY;
1089 		goto out;
1090 	}
1091 
1092 	oiommu = arch_data->iommu_dev;
1093 
1094 	/* get a handle to and enable the omap iommu */
1095 	ret = omap_iommu_attach(oiommu, omap_domain->pgtable);
1096 	if (ret) {
1097 		dev_err(dev, "can't get omap iommu: %d\n", ret);
1098 		goto out;
1099 	}
1100 
1101 	omap_domain->iommu_dev = oiommu;
1102 	omap_domain->dev = dev;
1103 	oiommu->domain = domain;
1104 
1105 out:
1106 	spin_unlock(&omap_domain->lock);
1107 	return ret;
1108 }
1109 
1110 static void _omap_iommu_detach_dev(struct omap_iommu_domain *omap_domain,
1111 				   struct device *dev)
1112 {
1113 	struct omap_iommu *oiommu = dev_to_omap_iommu(dev);
1114 
1115 	/* only a single device is supported per domain for now */
1116 	if (omap_domain->iommu_dev != oiommu) {
1117 		dev_err(dev, "invalid iommu device\n");
1118 		return;
1119 	}
1120 
1121 	iopgtable_clear_entry_all(oiommu);
1122 
1123 	omap_iommu_detach(oiommu);
1124 
1125 	omap_domain->iommu_dev = NULL;
1126 	omap_domain->dev = NULL;
1127 	oiommu->domain = NULL;
1128 }
1129 
1130 static void omap_iommu_detach_dev(struct iommu_domain *domain,
1131 				  struct device *dev)
1132 {
1133 	struct omap_iommu_domain *omap_domain = to_omap_domain(domain);
1134 
1135 	spin_lock(&omap_domain->lock);
1136 	_omap_iommu_detach_dev(omap_domain, dev);
1137 	spin_unlock(&omap_domain->lock);
1138 }
1139 
1140 static struct iommu_domain *omap_iommu_domain_alloc(unsigned type)
1141 {
1142 	struct omap_iommu_domain *omap_domain;
1143 
1144 	if (type != IOMMU_DOMAIN_UNMANAGED)
1145 		return NULL;
1146 
1147 	omap_domain = kzalloc(sizeof(*omap_domain), GFP_KERNEL);
1148 	if (!omap_domain)
1149 		goto out;
1150 
1151 	omap_domain->pgtable = kzalloc(IOPGD_TABLE_SIZE, GFP_KERNEL);
1152 	if (!omap_domain->pgtable)
1153 		goto fail_nomem;
1154 
1155 	/*
1156 	 * should never fail, but please keep this around to ensure
1157 	 * we keep the hardware happy
1158 	 */
1159 	if (WARN_ON(!IS_ALIGNED((long)omap_domain->pgtable, IOPGD_TABLE_SIZE)))
1160 		goto fail_align;
1161 
1162 	clean_dcache_area(omap_domain->pgtable, IOPGD_TABLE_SIZE);
1163 	spin_lock_init(&omap_domain->lock);
1164 
1165 	omap_domain->domain.geometry.aperture_start = 0;
1166 	omap_domain->domain.geometry.aperture_end   = (1ULL << 32) - 1;
1167 	omap_domain->domain.geometry.force_aperture = true;
1168 
1169 	return &omap_domain->domain;
1170 
1171 fail_align:
1172 	kfree(omap_domain->pgtable);
1173 fail_nomem:
1174 	kfree(omap_domain);
1175 out:
1176 	return NULL;
1177 }
1178 
1179 static void omap_iommu_domain_free(struct iommu_domain *domain)
1180 {
1181 	struct omap_iommu_domain *omap_domain = to_omap_domain(domain);
1182 
1183 	/*
1184 	 * An iommu device is still attached
1185 	 * (currently, only one device can be attached) ?
1186 	 */
1187 	if (omap_domain->iommu_dev)
1188 		_omap_iommu_detach_dev(omap_domain, omap_domain->dev);
1189 
1190 	kfree(omap_domain->pgtable);
1191 	kfree(omap_domain);
1192 }
1193 
1194 static phys_addr_t omap_iommu_iova_to_phys(struct iommu_domain *domain,
1195 					   dma_addr_t da)
1196 {
1197 	struct omap_iommu_domain *omap_domain = to_omap_domain(domain);
1198 	struct omap_iommu *oiommu = omap_domain->iommu_dev;
1199 	struct device *dev = oiommu->dev;
1200 	u32 *pgd, *pte;
1201 	phys_addr_t ret = 0;
1202 
1203 	iopgtable_lookup_entry(oiommu, da, &pgd, &pte);
1204 
1205 	if (pte) {
1206 		if (iopte_is_small(*pte))
1207 			ret = omap_iommu_translate(*pte, da, IOPTE_MASK);
1208 		else if (iopte_is_large(*pte))
1209 			ret = omap_iommu_translate(*pte, da, IOLARGE_MASK);
1210 		else
1211 			dev_err(dev, "bogus pte 0x%x, da 0x%llx", *pte,
1212 				(unsigned long long)da);
1213 	} else {
1214 		if (iopgd_is_section(*pgd))
1215 			ret = omap_iommu_translate(*pgd, da, IOSECTION_MASK);
1216 		else if (iopgd_is_super(*pgd))
1217 			ret = omap_iommu_translate(*pgd, da, IOSUPER_MASK);
1218 		else
1219 			dev_err(dev, "bogus pgd 0x%x, da 0x%llx", *pgd,
1220 				(unsigned long long)da);
1221 	}
1222 
1223 	return ret;
1224 }
1225 
1226 static int omap_iommu_add_device(struct device *dev)
1227 {
1228 	struct omap_iommu_arch_data *arch_data;
1229 	struct omap_iommu *oiommu;
1230 	struct iommu_group *group;
1231 	struct device_node *np;
1232 	struct platform_device *pdev;
1233 	int ret;
1234 
1235 	/*
1236 	 * Allocate the archdata iommu structure for DT-based devices.
1237 	 *
1238 	 * TODO: Simplify this when removing non-DT support completely from the
1239 	 * IOMMU users.
1240 	 */
1241 	if (!dev->of_node)
1242 		return 0;
1243 
1244 	np = of_parse_phandle(dev->of_node, "iommus", 0);
1245 	if (!np)
1246 		return 0;
1247 
1248 	pdev = of_find_device_by_node(np);
1249 	if (WARN_ON(!pdev)) {
1250 		of_node_put(np);
1251 		return -EINVAL;
1252 	}
1253 
1254 	oiommu = platform_get_drvdata(pdev);
1255 	if (!oiommu) {
1256 		of_node_put(np);
1257 		return -EINVAL;
1258 	}
1259 
1260 	arch_data = kzalloc(sizeof(*arch_data), GFP_KERNEL);
1261 	if (!arch_data) {
1262 		of_node_put(np);
1263 		return -ENOMEM;
1264 	}
1265 
1266 	ret = iommu_device_link(&oiommu->iommu, dev);
1267 	if (ret) {
1268 		kfree(arch_data);
1269 		of_node_put(np);
1270 		return ret;
1271 	}
1272 
1273 	arch_data->iommu_dev = oiommu;
1274 	dev->archdata.iommu = arch_data;
1275 
1276 	/*
1277 	 * IOMMU group initialization calls into omap_iommu_device_group, which
1278 	 * needs a valid dev->archdata.iommu pointer
1279 	 */
1280 	group = iommu_group_get_for_dev(dev);
1281 	if (IS_ERR(group)) {
1282 		iommu_device_unlink(&oiommu->iommu, dev);
1283 		dev->archdata.iommu = NULL;
1284 		kfree(arch_data);
1285 		return PTR_ERR(group);
1286 	}
1287 	iommu_group_put(group);
1288 
1289 	of_node_put(np);
1290 
1291 	return 0;
1292 }
1293 
1294 static void omap_iommu_remove_device(struct device *dev)
1295 {
1296 	struct omap_iommu_arch_data *arch_data = dev->archdata.iommu;
1297 
1298 	if (!dev->of_node || !arch_data)
1299 		return;
1300 
1301 	iommu_device_unlink(&arch_data->iommu_dev->iommu, dev);
1302 	iommu_group_remove_device(dev);
1303 
1304 	dev->archdata.iommu = NULL;
1305 	kfree(arch_data);
1306 
1307 }
1308 
1309 static struct iommu_group *omap_iommu_device_group(struct device *dev)
1310 {
1311 	struct omap_iommu_arch_data *arch_data = dev->archdata.iommu;
1312 	struct iommu_group *group = ERR_PTR(-EINVAL);
1313 
1314 	if (arch_data->iommu_dev)
1315 		group = arch_data->iommu_dev->group;
1316 
1317 	return group;
1318 }
1319 
1320 static const struct iommu_ops omap_iommu_ops = {
1321 	.domain_alloc	= omap_iommu_domain_alloc,
1322 	.domain_free	= omap_iommu_domain_free,
1323 	.attach_dev	= omap_iommu_attach_dev,
1324 	.detach_dev	= omap_iommu_detach_dev,
1325 	.map		= omap_iommu_map,
1326 	.unmap		= omap_iommu_unmap,
1327 	.map_sg		= default_iommu_map_sg,
1328 	.iova_to_phys	= omap_iommu_iova_to_phys,
1329 	.add_device	= omap_iommu_add_device,
1330 	.remove_device	= omap_iommu_remove_device,
1331 	.device_group	= omap_iommu_device_group,
1332 	.pgsize_bitmap	= OMAP_IOMMU_PGSIZES,
1333 };
1334 
1335 static int __init omap_iommu_init(void)
1336 {
1337 	struct kmem_cache *p;
1338 	const unsigned long flags = SLAB_HWCACHE_ALIGN;
1339 	size_t align = 1 << 10; /* L2 pagetable alignement */
1340 	struct device_node *np;
1341 	int ret;
1342 
1343 	np = of_find_matching_node(NULL, omap_iommu_of_match);
1344 	if (!np)
1345 		return 0;
1346 
1347 	of_node_put(np);
1348 
1349 	p = kmem_cache_create("iopte_cache", IOPTE_TABLE_SIZE, align, flags,
1350 			      iopte_cachep_ctor);
1351 	if (!p)
1352 		return -ENOMEM;
1353 	iopte_cachep = p;
1354 
1355 	omap_iommu_debugfs_init();
1356 
1357 	ret = platform_driver_register(&omap_iommu_driver);
1358 	if (ret) {
1359 		pr_err("%s: failed to register driver\n", __func__);
1360 		goto fail_driver;
1361 	}
1362 
1363 	ret = bus_set_iommu(&platform_bus_type, &omap_iommu_ops);
1364 	if (ret)
1365 		goto fail_bus;
1366 
1367 	return 0;
1368 
1369 fail_bus:
1370 	platform_driver_unregister(&omap_iommu_driver);
1371 fail_driver:
1372 	kmem_cache_destroy(iopte_cachep);
1373 	return ret;
1374 }
1375 subsys_initcall(omap_iommu_init);
1376 /* must be ready before omap3isp is probed */
1377