drivers/iommu/omap-iovmm.c

   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
  29 static struct kmem_cache *iovm_area_cachep;
  30
  31 /* return the offset of the first scatterlist entry in a sg table */
  32 static 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 */
  41 static 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
  73 static 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  */
  86 static 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') */
 108 static 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) */
 144 static 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' */
 156 static 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
 199 err_out:
 200         WARN_ON(1); /* FIXME: cleanup some mpu mappings */
 201         vunmap(new->addr);
 202         return ERR_PTR(-EAGAIN);
 203 }
 204
 205 static inline void vunmap_sg(const void *va)
 206 {
 207         vunmap(va);
 208 }
 209
 210 static 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  */
 239 struct 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 }
 250 EXPORT_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  */
 256 static 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
 307 found:
 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
 331 static 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  */
 354 void *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;
 368 out:
 369         mutex_unlock(&obj->mmap_lock);
 370
 371         return va;
 372 }
 373 EXPORT_SYMBOL_GPL(omap_da_to_va);
 374
 375 static 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
 399 static 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' */
 409 static 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
 445 err_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 */
 462 static 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 */
 497 static 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);
 533 out:
 534         mutex_unlock(&obj->mmap_lock);
 535
 536         return sgt;
 537 }
 538
 539 static 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
 566 err_map:
 567         free_iovm_area(obj, new);
 568 err_alloc_iovma:
 569         mutex_unlock(&obj->mmap_lock);
 570         return err;
 571 }
 572
 573 static 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  */
 591 u32 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 }
 621 EXPORT_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  */
 632 struct sg_table *
 633 omap_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 }
 648 EXPORT_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  */
 660 u32
 661 omap_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
 693 err_iommu_vmap:
 694         sgtable_drain_vmalloc(sgt);
 695         sgtable_free(sgt);
 696 err_sgt_alloc:
 697         vfree(va);
 698         return da;
 699 }
 700 EXPORT_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  */
 710 void 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 }
 722 EXPORT_SYMBOL_GPL(omap_iommu_vfree);
 723
 724 static 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 }
 737 module_init(iovmm_init);
 738
 739 static void __exit iovmm_exit(void)
 740 {
 741         kmem_cache_destroy(iovm_area_cachep);
 742 }
 743 module_exit(iovmm_exit);
 744
 745 MODULE_DESCRIPTION("omap iommu: simple virtual address space management");
 746 MODULE_AUTHOR("Hiroshi DOYU <Hiroshi.DOYU@nokia.com>");
 747 MODULE_LICENSE("GPL v2");