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