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1/*
2 * omap iommu: simple virtual address space management
3 *
4 * Copyright (C) 2008-2009 Nokia Corporation
5 *
6 * Written by Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/module.h>
14#include <linux/err.h>
15#include <linux/slab.h>
16#include <linux/vmalloc.h>
17#include <linux/device.h>
18#include <linux/scatterlist.h>
19#include <linux/iommu.h>
20
21#include <asm/cacheflush.h>
22#include <asm/mach/map.h>
23
24#include <plat/iommu.h>
25#include <plat/iovmm.h>
26
27#include <plat/iopgtable.h>
28
29static struct kmem_cache *iovm_area_cachep;
30
31/* return the offset of the first scatterlist entry in a sg table */
32static unsigned int sgtable_offset(const struct sg_table *sgt)
33{
34 if (!sgt || !sgt->nents)
35 return 0;
36
37 return sgt->sgl->offset;
38}
39
40/* return total bytes of sg buffers */
41static size_t sgtable_len(const struct sg_table *sgt)
42{
43 unsigned int i, total = 0;
44 struct scatterlist *sg;
45
46 if (!sgt)
47 return 0;
48
49 for_each_sg(sgt->sgl, sg, sgt->nents, i) {
50 size_t bytes;
51
52 bytes = sg->length + sg->offset;
53
54 if (!iopgsz_ok(bytes)) {
55 pr_err("%s: sg[%d] not iommu pagesize(%u %u)\n",
56 __func__, i, bytes, sg->offset);
57 return 0;
58 }
59
60 if (i && sg->offset) {
61 pr_err("%s: sg[%d] offset not allowed in internal "
62 "entries\n", __func__, i);
63 return 0;
64 }
65
66 total += bytes;
67 }
68
69 return total;
70}
71#define sgtable_ok(x) (!!sgtable_len(x))
72
73static unsigned max_alignment(u32 addr)
74{
75 int i;
76 unsigned pagesize[] = { SZ_16M, SZ_1M, SZ_64K, SZ_4K, };
77 for (i = 0; i < ARRAY_SIZE(pagesize) && addr & (pagesize[i] - 1); i++)
78 ;
79 return (i < ARRAY_SIZE(pagesize)) ? pagesize[i] : 0;
80}
81
82/*
83 * calculate the optimal number sg elements from total bytes based on
84 * iommu superpages
85 */
86static unsigned sgtable_nents(size_t bytes, u32 da, u32 pa)
87{
88 unsigned nr_entries = 0, ent_sz;
89
90 if (!IS_ALIGNED(bytes, PAGE_SIZE)) {
91 pr_err("%s: wrong size %08x\n", __func__, bytes);
92 return 0;
93 }
94
95 while (bytes) {
96 ent_sz = max_alignment(da | pa);
97 ent_sz = min_t(unsigned, ent_sz, iopgsz_max(bytes));
98 nr_entries++;
99 da += ent_sz;
100 pa += ent_sz;
101 bytes -= ent_sz;
102 }
103
104 return nr_entries;
105}
106
107/* allocate and initialize sg_table header(a kind of 'superblock') */
108static struct sg_table *sgtable_alloc(const size_t bytes, u32 flags,
109 u32 da, u32 pa)
110{
111 unsigned int nr_entries;
112 int err;
113 struct sg_table *sgt;
114
115 if (!bytes)
116 return ERR_PTR(-EINVAL);
117
118 if (!IS_ALIGNED(bytes, PAGE_SIZE))
119 return ERR_PTR(-EINVAL);
120
121 if (flags & IOVMF_LINEAR) {
122 nr_entries = sgtable_nents(bytes, da, pa);
123 if (!nr_entries)
124 return ERR_PTR(-EINVAL);
125 } else
126 nr_entries = bytes / PAGE_SIZE;
127
128 sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
129 if (!sgt)
130 return ERR_PTR(-ENOMEM);
131
132 err = sg_alloc_table(sgt, nr_entries, GFP_KERNEL);
133 if (err) {
134 kfree(sgt);
135 return ERR_PTR(err);
136 }
137
138 pr_debug("%s: sgt:%p(%d entries)\n", __func__, sgt, nr_entries);
139
140 return sgt;
141}
142
143/* free sg_table header(a kind of superblock) */
144static void sgtable_free(struct sg_table *sgt)
145{
146 if (!sgt)
147 return;
148
149 sg_free_table(sgt);
150 kfree(sgt);
151
152 pr_debug("%s: sgt:%p\n", __func__, sgt);
153}
154
155/* map 'sglist' to a contiguous mpu virtual area and return 'va' */
156static void *vmap_sg(const struct sg_table *sgt)
157{
158 u32 va;
159 size_t total;
160 unsigned int i;
161 struct scatterlist *sg;
162 struct vm_struct *new;
163 const struct mem_type *mtype;
164
165 mtype = get_mem_type(MT_DEVICE);
166 if (!mtype)
167 return ERR_PTR(-EINVAL);
168
169 total = sgtable_len(sgt);
170 if (!total)
171 return ERR_PTR(-EINVAL);
172
173 new = __get_vm_area(total, VM_IOREMAP, VMALLOC_START, VMALLOC_END);
174 if (!new)
175 return ERR_PTR(-ENOMEM);
176 va = (u32)new->addr;
177
178 for_each_sg(sgt->sgl, sg, sgt->nents, i) {
179 size_t bytes;
180 u32 pa;
181 int err;
182
183 pa = sg_phys(sg) - sg->offset;
184 bytes = sg->length + sg->offset;
185
186 BUG_ON(bytes != PAGE_SIZE);
187
188 err = ioremap_page(va, pa, mtype);
189 if (err)
190 goto err_out;
191
192 va += bytes;
193 }
194
195 flush_cache_vmap((unsigned long)new->addr,
196 (unsigned long)(new->addr + total));
197 return new->addr;
198
199err_out:
200 WARN_ON(1); /* FIXME: cleanup some mpu mappings */
201 vunmap(new->addr);
202 return ERR_PTR(-EAGAIN);
203}
204
205static inline void vunmap_sg(const void *va)
206{
207 vunmap(va);
208}
209
210static struct iovm_struct *__find_iovm_area(struct omap_iommu *obj,
211 const u32 da)
212{
213 struct iovm_struct *tmp;
214
215 list_for_each_entry(tmp, &obj->mmap, list) {
216 if ((da >= tmp->da_start) && (da < tmp->da_end)) {
217 size_t len;
218
219 len = tmp->da_end - tmp->da_start;
220
221 dev_dbg(obj->dev, "%s: %08x-%08x-%08x(%x) %08x\n",
222 __func__, tmp->da_start, da, tmp->da_end, len,
223 tmp->flags);
224
225 return tmp;
226 }
227 }
228
229 return NULL;
230}
231
232/**
233 * omap_find_iovm_area - find iovma which includes @da
234 * @dev: client device
235 * @da: iommu device virtual address
236 *
237 * Find the existing iovma starting at @da
238 */
239struct iovm_struct *omap_find_iovm_area(struct device *dev, u32 da)
240{
241 struct omap_iommu *obj = dev_to_omap_iommu(dev);
242 struct iovm_struct *area;
243
244 mutex_lock(&obj->mmap_lock);
245 area = __find_iovm_area(obj, da);
246 mutex_unlock(&obj->mmap_lock);
247
248 return area;
249}
250EXPORT_SYMBOL_GPL(omap_find_iovm_area);
251
252/*
253 * This finds the hole(area) which fits the requested address and len
254 * in iovmas mmap, and returns the new allocated iovma.
255 */
256static struct iovm_struct *alloc_iovm_area(struct omap_iommu *obj, u32 da,
257 size_t bytes, u32 flags)
258{
259 struct iovm_struct *new, *tmp;
260 u32 start, prev_end, alignment;
261
262 if (!obj || !bytes)
263 return ERR_PTR(-EINVAL);
264
265 start = da;
266 alignment = PAGE_SIZE;
267
268 if (~flags & IOVMF_DA_FIXED) {
269 /* Don't map address 0 */
270 start = obj->da_start ? obj->da_start : alignment;
271
272 if (flags & IOVMF_LINEAR)
273 alignment = iopgsz_max(bytes);
274 start = roundup(start, alignment);
275 } else if (start < obj->da_start || start > obj->da_end ||
276 obj->da_end - start < bytes) {
277 return ERR_PTR(-EINVAL);
278 }
279
280 tmp = NULL;
281 if (list_empty(&obj->mmap))
282 goto found;
283
284 prev_end = 0;
285 list_for_each_entry(tmp, &obj->mmap, list) {
286
287 if (prev_end > start)
288 break;
289
290 if (tmp->da_start > start && (tmp->da_start - start) >= bytes)
291 goto found;
292
293 if (tmp->da_end >= start && ~flags & IOVMF_DA_FIXED)
294 start = roundup(tmp->da_end + 1, alignment);
295
296 prev_end = tmp->da_end;
297 }
298
299 if ((start >= prev_end) && (obj->da_end - start >= bytes))
300 goto found;
301
302 dev_dbg(obj->dev, "%s: no space to fit %08x(%x) flags: %08x\n",
303 __func__, da, bytes, flags);
304
305 return ERR_PTR(-EINVAL);
306
307found:
308 new = kmem_cache_zalloc(iovm_area_cachep, GFP_KERNEL);
309 if (!new)
310 return ERR_PTR(-ENOMEM);
311
312 new->iommu = obj;
313 new->da_start = start;
314 new->da_end = start + bytes;
315 new->flags = flags;
316
317 /*
318 * keep ascending order of iovmas
319 */
320 if (tmp)
321 list_add_tail(&new->list, &tmp->list);
322 else
323 list_add(&new->list, &obj->mmap);
324
325 dev_dbg(obj->dev, "%s: found %08x-%08x-%08x(%x) %08x\n",
326 __func__, new->da_start, start, new->da_end, bytes, flags);
327
328 return new;
329}
330
331static void free_iovm_area(struct omap_iommu *obj, struct iovm_struct *area)
332{
333 size_t bytes;
334
335 BUG_ON(!obj || !area);
336
337 bytes = area->da_end - area->da_start;
338
339 dev_dbg(obj->dev, "%s: %08x-%08x(%x) %08x\n",
340 __func__, area->da_start, area->da_end, bytes, area->flags);
341
342 list_del(&area->list);
343 kmem_cache_free(iovm_area_cachep, area);
344}
345
346/**
347 * omap_da_to_va - convert (d) to (v)
348 * @dev: client device
349 * @da: iommu device virtual address
350 * @va: mpu virtual address
351 *
352 * Returns mpu virtual addr which corresponds to a given device virtual addr
353 */
354void *omap_da_to_va(struct device *dev, u32 da)
355{
356 struct omap_iommu *obj = dev_to_omap_iommu(dev);
357 void *va = NULL;
358 struct iovm_struct *area;
359
360 mutex_lock(&obj->mmap_lock);
361
362 area = __find_iovm_area(obj, da);
363 if (!area) {
364 dev_dbg(obj->dev, "%s: no da area(%08x)\n", __func__, da);
365 goto out;
366 }
367 va = area->va;
368out:
369 mutex_unlock(&obj->mmap_lock);
370
371 return va;
372}
373EXPORT_SYMBOL_GPL(omap_da_to_va);
374
375static void sgtable_fill_vmalloc(struct sg_table *sgt, void *_va)
376{
377 unsigned int i;
378 struct scatterlist *sg;
379 void *va = _va;
380 void *va_end;
381
382 for_each_sg(sgt->sgl, sg, sgt->nents, i) {
383 struct page *pg;
384 const size_t bytes = PAGE_SIZE;
385
386 /*
387 * iommu 'superpage' isn't supported with 'omap_iommu_vmalloc()'
388 */
389 pg = vmalloc_to_page(va);
390 BUG_ON(!pg);
391 sg_set_page(sg, pg, bytes, 0);
392
393 va += bytes;
394 }
395
396 va_end = _va + PAGE_SIZE * i;
397}
398
399static inline void sgtable_drain_vmalloc(struct sg_table *sgt)
400{
401 /*
402 * Actually this is not necessary at all, just exists for
403 * consistency of the code readability.
404 */
405 BUG_ON(!sgt);
406}
407
408/* create 'da' <-> 'pa' mapping from 'sgt' */
409static int map_iovm_area(struct iommu_domain *domain, struct iovm_struct *new,
410 const struct sg_table *sgt, u32 flags)
411{
412 int err;
413 unsigned int i, j;
414 struct scatterlist *sg;
415 u32 da = new->da_start;
416
417 if (!domain || !sgt)
418 return -EINVAL;
419
420 BUG_ON(!sgtable_ok(sgt));
421
422 for_each_sg(sgt->sgl, sg, sgt->nents, i) {
423 u32 pa;
424 size_t bytes;
425
426 pa = sg_phys(sg) - sg->offset;
427 bytes = sg->length + sg->offset;
428
429 flags &= ~IOVMF_PGSZ_MASK;
430
431 if (bytes_to_iopgsz(bytes) < 0)
432 goto err_out;
433
434 pr_debug("%s: [%d] %08x %08x(%x)\n", __func__,
435 i, da, pa, bytes);
436
437 err = iommu_map(domain, da, pa, bytes, flags);
438 if (err)
439 goto err_out;
440
441 da += bytes;
442 }
443 return 0;
444
445err_out:
446 da = new->da_start;
447
448 for_each_sg(sgt->sgl, sg, i, j) {
449 size_t bytes;
450
451 bytes = sg->length + sg->offset;
452
453 /* ignore failures.. we're already handling one */
454 iommu_unmap(domain, da, bytes);
455
456 da += bytes;
457 }
458 return err;
459}
460
461/* release 'da' <-> 'pa' mapping */
462static void unmap_iovm_area(struct iommu_domain *domain, struct omap_iommu *obj,
463 struct iovm_struct *area)
464{
465 u32 start;
466 size_t total = area->da_end - area->da_start;
467 const struct sg_table *sgt = area->sgt;
468 struct scatterlist *sg;
469 int i;
470 size_t unmapped;
471
472 BUG_ON(!sgtable_ok(sgt));
473 BUG_ON((!total) || !IS_ALIGNED(total, PAGE_SIZE));
474
475 start = area->da_start;
476 for_each_sg(sgt->sgl, sg, sgt->nents, i) {
477 size_t bytes;
478
479 bytes = sg->length + sg->offset;
480
481 unmapped = iommu_unmap(domain, start, bytes);
482 if (unmapped < bytes)
483 break;
484
485 dev_dbg(obj->dev, "%s: unmap %08x(%x) %08x\n",
486 __func__, start, bytes, area->flags);
487
488 BUG_ON(!IS_ALIGNED(bytes, PAGE_SIZE));
489
490 total -= bytes;
491 start += bytes;
492 }
493 BUG_ON(total);
494}
495
496/* template function for all unmapping */
497static struct sg_table *unmap_vm_area(struct iommu_domain *domain,
498 struct omap_iommu *obj, const u32 da,
499 void (*fn)(const void *), u32 flags)
500{
501 struct sg_table *sgt = NULL;
502 struct iovm_struct *area;
503
504 if (!IS_ALIGNED(da, PAGE_SIZE)) {
505 dev_err(obj->dev, "%s: alignment err(%08x)\n", __func__, da);
506 return NULL;
507 }
508
509 mutex_lock(&obj->mmap_lock);
510
511 area = __find_iovm_area(obj, da);
512 if (!area) {
513 dev_dbg(obj->dev, "%s: no da area(%08x)\n", __func__, da);
514 goto out;
515 }
516
517 if ((area->flags & flags) != flags) {
518 dev_err(obj->dev, "%s: wrong flags(%08x)\n", __func__,
519 area->flags);
520 goto out;
521 }
522 sgt = (struct sg_table *)area->sgt;
523
524 unmap_iovm_area(domain, obj, area);
525
526 fn(area->va);
527
528 dev_dbg(obj->dev, "%s: %08x-%08x-%08x(%x) %08x\n", __func__,
529 area->da_start, da, area->da_end,
530 area->da_end - area->da_start, area->flags);
531
532 free_iovm_area(obj, area);
533out:
534 mutex_unlock(&obj->mmap_lock);
535
536 return sgt;
537}
538
539static u32 map_iommu_region(struct iommu_domain *domain, struct omap_iommu *obj,
540 u32 da, const struct sg_table *sgt, void *va,
541 size_t bytes, u32 flags)
542{
543 int err = -ENOMEM;
544 struct iovm_struct *new;
545
546 mutex_lock(&obj->mmap_lock);
547
548 new = alloc_iovm_area(obj, da, bytes, flags);
549 if (IS_ERR(new)) {
550 err = PTR_ERR(new);
551 goto err_alloc_iovma;
552 }
553 new->va = va;
554 new->sgt = sgt;
555
556 if (map_iovm_area(domain, new, sgt, new->flags))
557 goto err_map;
558
559 mutex_unlock(&obj->mmap_lock);
560
561 dev_dbg(obj->dev, "%s: da:%08x(%x) flags:%08x va:%p\n",
562 __func__, new->da_start, bytes, new->flags, va);
563
564 return new->da_start;
565
566err_map:
567 free_iovm_area(obj, new);
568err_alloc_iovma:
569 mutex_unlock(&obj->mmap_lock);
570 return err;
571}
572
573static inline u32
574__iommu_vmap(struct iommu_domain *domain, struct omap_iommu *obj,
575 u32 da, const struct sg_table *sgt,
576 void *va, size_t bytes, u32 flags)
577{
578 return map_iommu_region(domain, obj, da, sgt, va, bytes, flags);
579}
580
581/**
582 * omap_iommu_vmap - (d)-(p)-(v) address mapper
583 * @domain: iommu domain
584 * @dev: client device
585 * @sgt: address of scatter gather table
586 * @flags: iovma and page property
587 *
588 * Creates 1-n-1 mapping with given @sgt and returns @da.
589 * All @sgt element must be io page size aligned.
590 */
591u32 omap_iommu_vmap(struct iommu_domain *domain, struct device *dev, u32 da,
592 const struct sg_table *sgt, u32 flags)
593{
594 struct omap_iommu *obj = dev_to_omap_iommu(dev);
595 size_t bytes;
596 void *va = NULL;
597
598 if (!obj || !obj->dev || !sgt)
599 return -EINVAL;
600
601 bytes = sgtable_len(sgt);
602 if (!bytes)
603 return -EINVAL;
604 bytes = PAGE_ALIGN(bytes);
605
606 if (flags & IOVMF_MMIO) {
607 va = vmap_sg(sgt);
608 if (IS_ERR(va))
609 return PTR_ERR(va);
610 }
611
612 flags |= IOVMF_DISCONT;
613 flags |= IOVMF_MMIO;
614
615 da = __iommu_vmap(domain, obj, da, sgt, va, bytes, flags);
616 if (IS_ERR_VALUE(da))
617 vunmap_sg(va);
618
619 return da + sgtable_offset(sgt);
620}
621EXPORT_SYMBOL_GPL(omap_iommu_vmap);
622
623/**
624 * omap_iommu_vunmap - release virtual mapping obtained by 'omap_iommu_vmap()'
625 * @domain: iommu domain
626 * @dev: client device
627 * @da: iommu device virtual address
628 *
629 * Free the iommu virtually contiguous memory area starting at
630 * @da, which was returned by 'omap_iommu_vmap()'.
631 */
632struct sg_table *
633omap_iommu_vunmap(struct iommu_domain *domain, struct device *dev, u32 da)
634{
635 struct omap_iommu *obj = dev_to_omap_iommu(dev);
636 struct sg_table *sgt;
637 /*
638 * 'sgt' is allocated before 'omap_iommu_vmalloc()' is called.
639 * Just returns 'sgt' to the caller to free
640 */
641 da &= PAGE_MASK;
642 sgt = unmap_vm_area(domain, obj, da, vunmap_sg,
643 IOVMF_DISCONT | IOVMF_MMIO);
644 if (!sgt)
645 dev_dbg(obj->dev, "%s: No sgt\n", __func__);
646 return sgt;
647}
648EXPORT_SYMBOL_GPL(omap_iommu_vunmap);
649
650/**
651 * omap_iommu_vmalloc - (d)-(p)-(v) address allocator and mapper
652 * @dev: client device
653 * @da: contiguous iommu virtual memory
654 * @bytes: allocation size
655 * @flags: iovma and page property
656 *
657 * Allocate @bytes linearly and creates 1-n-1 mapping and returns
658 * @da again, which might be adjusted if 'IOVMF_DA_FIXED' is not set.
659 */
660u32
661omap_iommu_vmalloc(struct iommu_domain *domain, struct device *dev, u32 da,
662 size_t bytes, u32 flags)
663{
664 struct omap_iommu *obj = dev_to_omap_iommu(dev);
665 void *va;
666 struct sg_table *sgt;
667
668 if (!obj || !obj->dev || !bytes)
669 return -EINVAL;
670
671 bytes = PAGE_ALIGN(bytes);
672
673 va = vmalloc(bytes);
674 if (!va)
675 return -ENOMEM;
676
677 flags |= IOVMF_DISCONT;
678 flags |= IOVMF_ALLOC;
679
680 sgt = sgtable_alloc(bytes, flags, da, 0);
681 if (IS_ERR(sgt)) {
682 da = PTR_ERR(sgt);
683 goto err_sgt_alloc;
684 }
685 sgtable_fill_vmalloc(sgt, va);
686
687 da = __iommu_vmap(domain, obj, da, sgt, va, bytes, flags);
688 if (IS_ERR_VALUE(da))
689 goto err_iommu_vmap;
690
691 return da;
692
693err_iommu_vmap:
694 sgtable_drain_vmalloc(sgt);
695 sgtable_free(sgt);
696err_sgt_alloc:
697 vfree(va);
698 return da;
699}
700EXPORT_SYMBOL_GPL(omap_iommu_vmalloc);
701
702/**
703 * omap_iommu_vfree - release memory allocated by 'omap_iommu_vmalloc()'
704 * @dev: client device
705 * @da: iommu device virtual address
706 *
707 * Frees the iommu virtually continuous memory area starting at
708 * @da, as obtained from 'omap_iommu_vmalloc()'.
709 */
710void omap_iommu_vfree(struct iommu_domain *domain, struct device *dev,
711 const u32 da)
712{
713 struct omap_iommu *obj = dev_to_omap_iommu(dev);
714 struct sg_table *sgt;
715
716 sgt = unmap_vm_area(domain, obj, da, vfree,
717 IOVMF_DISCONT | IOVMF_ALLOC);
718 if (!sgt)
719 dev_dbg(obj->dev, "%s: No sgt\n", __func__);
720 sgtable_free(sgt);
721}
722EXPORT_SYMBOL_GPL(omap_iommu_vfree);
723
724static int __init iovmm_init(void)
725{
726 const unsigned long flags = SLAB_HWCACHE_ALIGN;
727 struct kmem_cache *p;
728
729 p = kmem_cache_create("iovm_area_cache", sizeof(struct iovm_struct), 0,
730 flags, NULL);
731 if (!p)
732 return -ENOMEM;
733 iovm_area_cachep = p;
734
735 return 0;
736}
737module_init(iovmm_init);
738
739static void __exit iovmm_exit(void)
740{
741 kmem_cache_destroy(iovm_area_cachep);
742}
743module_exit(iovmm_exit);
744
745MODULE_DESCRIPTION("omap iommu: simple virtual address space management");
746MODULE_AUTHOR("Hiroshi DOYU <Hiroshi.DOYU@nokia.com>");
747MODULE_LICENSE("GPL v2");