arch/s390/pci/pci_dma.c

   1 /*
   2  * Copyright IBM Corp. 2012
   3  *
   4  * Author(s):
   5  *   Jan Glauber <jang@linux.vnet.ibm.com>
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/slab.h>
  10 #include <linux/export.h>
  11 #include <linux/iommu-helper.h>
  12 #include <linux/dma-mapping.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/pci.h>
  15 #include <asm/pci_dma.h>
  16
  17 static struct kmem_cache *dma_region_table_cache;
  18 static struct kmem_cache *dma_page_table_cache;
  19 static int s390_iommu_strict;
  20
  21 static int zpci_refresh_global(struct zpci_dev *zdev)
  22 {
  23         return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma,
  24                                   zdev->iommu_pages * PAGE_SIZE);
  25 }
  26
  27 unsigned long *dma_alloc_cpu_table(void)
  28 {
  29         unsigned long *table, *entry;
  30
  31         table = kmem_cache_alloc(dma_region_table_cache, GFP_ATOMIC);
  32         if (!table)
  33                 return NULL;
  34
  35         for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
  36                 *entry = ZPCI_TABLE_INVALID;
  37         return table;
  38 }
  39
  40 static void dma_free_cpu_table(void *table)
  41 {
  42         kmem_cache_free(dma_region_table_cache, table);
  43 }
  44
  45 static unsigned long *dma_alloc_page_table(void)
  46 {
  47         unsigned long *table, *entry;
  48
  49         table = kmem_cache_alloc(dma_page_table_cache, GFP_ATOMIC);
  50         if (!table)
  51                 return NULL;
  52
  53         for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
  54                 *entry = ZPCI_PTE_INVALID;
  55         return table;
  56 }
  57
  58 static void dma_free_page_table(void *table)
  59 {
  60         kmem_cache_free(dma_page_table_cache, table);
  61 }
  62
  63 static unsigned long *dma_get_seg_table_origin(unsigned long *entry)
  64 {
  65         unsigned long *sto;
  66
  67         if (reg_entry_isvalid(*entry))
  68                 sto = get_rt_sto(*entry);
  69         else {
  70                 sto = dma_alloc_cpu_table();
  71                 if (!sto)
  72                         return NULL;
  73
  74                 set_rt_sto(entry, sto);
  75                 validate_rt_entry(entry);
  76                 entry_clr_protected(entry);
  77         }
  78         return sto;
  79 }
  80
  81 static unsigned long *dma_get_page_table_origin(unsigned long *entry)
  82 {
  83         unsigned long *pto;
  84
  85         if (reg_entry_isvalid(*entry))
  86                 pto = get_st_pto(*entry);
  87         else {
  88                 pto = dma_alloc_page_table();
  89                 if (!pto)
  90                         return NULL;
  91                 set_st_pto(entry, pto);
  92                 validate_st_entry(entry);
  93                 entry_clr_protected(entry);
  94         }
  95         return pto;
  96 }
  97
  98 unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr)
  99 {
 100         unsigned long *sto, *pto;
 101         unsigned int rtx, sx, px;
 102
 103         rtx = calc_rtx(dma_addr);
 104         sto = dma_get_seg_table_origin(&rto[rtx]);
 105         if (!sto)
 106                 return NULL;
 107
 108         sx = calc_sx(dma_addr);
 109         pto = dma_get_page_table_origin(&sto[sx]);
 110         if (!pto)
 111                 return NULL;
 112
 113         px = calc_px(dma_addr);
 114         return &pto[px];
 115 }
 116
 117 void dma_update_cpu_trans(unsigned long *entry, void *page_addr, int flags)
 118 {
 119         if (flags & ZPCI_PTE_INVALID) {
 120                 invalidate_pt_entry(entry);
 121         } else {
 122                 set_pt_pfaa(entry, page_addr);
 123                 validate_pt_entry(entry);
 124         }
 125
 126         if (flags & ZPCI_TABLE_PROTECTED)
 127                 entry_set_protected(entry);
 128         else
 129                 entry_clr_protected(entry);
 130 }
 131
 132 static int __dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
 133                               dma_addr_t dma_addr, size_t size, int flags)
 134 {
 135         unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 136         u8 *page_addr = (u8 *) (pa & PAGE_MASK);
 137         unsigned long irq_flags;
 138         unsigned long *entry;
 139         int i, rc = 0;
 140
 141         if (!nr_pages)
 142                 return -EINVAL;
 143
 144         spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
 145         if (!zdev->dma_table) {
 146                 rc = -EINVAL;
 147                 goto out_unlock;
 148         }
 149
 150         for (i = 0; i < nr_pages; i++) {
 151                 entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
 152                 if (!entry) {
 153                         rc = -ENOMEM;
 154                         goto undo_cpu_trans;
 155                 }
 156                 dma_update_cpu_trans(entry, page_addr, flags);
 157                 page_addr += PAGE_SIZE;
 158                 dma_addr += PAGE_SIZE;
 159         }
 160
 161 undo_cpu_trans:
 162         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 163                 flags = ZPCI_PTE_INVALID;
 164                 while (i-- > 0) {
 165                         page_addr -= PAGE_SIZE;
 166                         dma_addr -= PAGE_SIZE;
 167                         entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
 168                         if (!entry)
 169                                 break;
 170                         dma_update_cpu_trans(entry, page_addr, flags);
 171                 }
 172         }
 173 out_unlock:
 174         spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
 175         return rc;
 176 }
 177
 178 static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
 179                            size_t size, int flags)
 180 {
 181         /*
 182          * With zdev->tlb_refresh == 0, rpcit is not required to establish new
 183          * translations when previously invalid translation-table entries are
 184          * validated. With lazy unmap, it also is skipped for previously valid
 185          * entries, but a global rpcit is then required before any address can
 186          * be re-used, i.e. after each iommu bitmap wrap-around.
 187          */
 188         if (!zdev->tlb_refresh &&
 189                         (!s390_iommu_strict ||
 190                         ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)))
 191                 return 0;
 192
 193         return zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
 194                                   PAGE_ALIGN(size));
 195 }
 196
 197 static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
 198                             dma_addr_t dma_addr, size_t size, int flags)
 199 {
 200         int rc;
 201
 202         rc = __dma_update_trans(zdev, pa, dma_addr, size, flags);
 203         if (rc)
 204                 return rc;
 205
 206         rc = __dma_purge_tlb(zdev, dma_addr, size, flags);
 207         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
 208                 __dma_update_trans(zdev, pa, dma_addr, size, ZPCI_PTE_INVALID);
 209
 210         return rc;
 211 }
 212
 213 void dma_free_seg_table(unsigned long entry)
 214 {
 215         unsigned long *sto = get_rt_sto(entry);
 216         int sx;
 217
 218         for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
 219                 if (reg_entry_isvalid(sto[sx]))
 220                         dma_free_page_table(get_st_pto(sto[sx]));
 221
 222         dma_free_cpu_table(sto);
 223 }
 224
 225 void dma_cleanup_tables(unsigned long *table)
 226 {
 227         int rtx;
 228
 229         if (!table)
 230                 return;
 231
 232         for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
 233                 if (reg_entry_isvalid(table[rtx]))
 234                         dma_free_seg_table(table[rtx]);
 235
 236         dma_free_cpu_table(table);
 237 }
 238
 239 static unsigned long __dma_alloc_iommu(struct device *dev,
 240                                        unsigned long start, int size)
 241 {
 242         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 243         unsigned long boundary_size;
 244
 245         boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
 246                               PAGE_SIZE) >> PAGE_SHIFT;
 247         return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
 248                                 start, size, zdev->start_dma >> PAGE_SHIFT,
 249                                 boundary_size, 0);
 250 }
 251
 252 static dma_addr_t dma_alloc_address(struct device *dev, int size)
 253 {
 254         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 255         unsigned long offset, flags;
 256
 257         spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 258         offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
 259         if (offset == -1) {
 260                 if (!zdev->tlb_refresh && !s390_iommu_strict) {
 261                         /* global flush before DMA addresses are reused */
 262                         if (zpci_refresh_global(zdev))
 263                                 goto out_error;
 264
 265                         bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
 266                                       zdev->lazy_bitmap, zdev->iommu_pages);
 267                         bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
 268                 }
 269                 /* wrap-around */
 270                 offset = __dma_alloc_iommu(dev, 0, size);
 271                 if (offset == -1)
 272                         goto out_error;
 273         }
 274         zdev->next_bit = offset + size;
 275         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 276
 277         return zdev->start_dma + offset * PAGE_SIZE;
 278
 279 out_error:
 280         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 281         return DMA_ERROR_CODE;
 282 }
 283
 284 static void dma_free_address(struct device *dev, dma_addr_t dma_addr, int size)
 285 {
 286         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 287         unsigned long flags, offset;
 288
 289         offset = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
 290
 291         spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 292         if (!zdev->iommu_bitmap)
 293                 goto out;
 294
 295         if (zdev->tlb_refresh || s390_iommu_strict)
 296                 bitmap_clear(zdev->iommu_bitmap, offset, size);
 297         else
 298                 bitmap_set(zdev->lazy_bitmap, offset, size);
 299
 300 out:
 301         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 302 }
 303
 304 static inline void zpci_err_dma(unsigned long rc, unsigned long addr)
 305 {
 306         struct {
 307                 unsigned long rc;
 308                 unsigned long addr;
 309         } __packed data = {rc, addr};
 310
 311         zpci_err_hex(&data, sizeof(data));
 312 }
 313
 314 static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
 315                                      unsigned long offset, size_t size,
 316                                      enum dma_data_direction direction,
 317                                      unsigned long attrs)
 318 {
 319         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 320         unsigned long pa = page_to_phys(page) + offset;
 321         int flags = ZPCI_PTE_VALID;
 322         unsigned long nr_pages;
 323         dma_addr_t dma_addr;
 324         int ret;
 325
 326         /* This rounds up number of pages based on size and offset */
 327         nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
 328         dma_addr = dma_alloc_address(dev, nr_pages);
 329         if (dma_addr == DMA_ERROR_CODE) {
 330                 ret = -ENOSPC;
 331                 goto out_err;
 332         }
 333
 334         /* Use rounded up size */
 335         size = nr_pages * PAGE_SIZE;
 336
 337         if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
 338                 flags |= ZPCI_TABLE_PROTECTED;
 339
 340         ret = dma_update_trans(zdev, pa, dma_addr, size, flags);
 341         if (ret)
 342                 goto out_free;
 343
 344         atomic64_add(nr_pages, &zdev->mapped_pages);
 345         return dma_addr + (offset & ~PAGE_MASK);
 346
 347 out_free:
 348         dma_free_address(dev, dma_addr, nr_pages);
 349 out_err:
 350         zpci_err("map error:\n");
 351         zpci_err_dma(ret, pa);
 352         return DMA_ERROR_CODE;
 353 }
 354
 355 static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
 356                                  size_t size, enum dma_data_direction direction,
 357                                  unsigned long attrs)
 358 {
 359         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 360         int npages, ret;
 361
 362         npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
 363         dma_addr = dma_addr & PAGE_MASK;
 364         ret = dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
 365                                ZPCI_PTE_INVALID);
 366         if (ret) {
 367                 zpci_err("unmap error:\n");
 368                 zpci_err_dma(ret, dma_addr);
 369                 return;
 370         }
 371
 372         atomic64_add(npages, &zdev->unmapped_pages);
 373         dma_free_address(dev, dma_addr, npages);
 374 }
 375
 376 static void *s390_dma_alloc(struct device *dev, size_t size,
 377                             dma_addr_t *dma_handle, gfp_t flag,
 378                             unsigned long attrs)
 379 {
 380         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 381         struct page *page;
 382         unsigned long pa;
 383         dma_addr_t map;
 384
 385         size = PAGE_ALIGN(size);
 386         page = alloc_pages(flag, get_order(size));
 387         if (!page)
 388                 return NULL;
 389
 390         pa = page_to_phys(page);
 391         memset((void *) pa, 0, size);
 392
 393         map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
 394         if (dma_mapping_error(dev, map)) {
 395                 free_pages(pa, get_order(size));
 396                 return NULL;
 397         }
 398
 399         atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
 400         if (dma_handle)
 401                 *dma_handle = map;
 402         return (void *) pa;
 403 }
 404
 405 static void s390_dma_free(struct device *dev, size_t size,
 406                           void *pa, dma_addr_t dma_handle,
 407                           unsigned long attrs)
 408 {
 409         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 410
 411         size = PAGE_ALIGN(size);
 412         atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
 413         s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, 0);
 414         free_pages((unsigned long) pa, get_order(size));
 415 }
 416
 417 /* Map a segment into a contiguous dma address area */
 418 static int __s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 419                              size_t size, dma_addr_t *handle,
 420                              enum dma_data_direction dir)
 421 {
 422         unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 423         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 424         dma_addr_t dma_addr_base, dma_addr;
 425         int flags = ZPCI_PTE_VALID;
 426         struct scatterlist *s;
 427         unsigned long pa = 0;
 428         int ret;
 429
 430         dma_addr_base = dma_alloc_address(dev, nr_pages);
 431         if (dma_addr_base == DMA_ERROR_CODE)
 432                 return -ENOMEM;
 433
 434         dma_addr = dma_addr_base;
 435         if (dir == DMA_NONE || dir == DMA_TO_DEVICE)
 436                 flags |= ZPCI_TABLE_PROTECTED;
 437
 438         for (s = sg; dma_addr < dma_addr_base + size; s = sg_next(s)) {
 439                 pa = page_to_phys(sg_page(s));
 440                 ret = __dma_update_trans(zdev, pa, dma_addr,
 441                                          s->offset + s->length, flags);
 442                 if (ret)
 443                         goto unmap;
 444
 445                 dma_addr += s->offset + s->length;
 446         }
 447         ret = __dma_purge_tlb(zdev, dma_addr_base, size, flags);
 448         if (ret)
 449                 goto unmap;
 450
 451         *handle = dma_addr_base;
 452         atomic64_add(nr_pages, &zdev->mapped_pages);
 453
 454         return ret;
 455
 456 unmap:
 457         dma_update_trans(zdev, 0, dma_addr_base, dma_addr - dma_addr_base,
 458                          ZPCI_PTE_INVALID);
 459         dma_free_address(dev, dma_addr_base, nr_pages);
 460         zpci_err("map error:\n");
 461         zpci_err_dma(ret, pa);
 462         return ret;
 463 }
 464
 465 static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 466                            int nr_elements, enum dma_data_direction dir,
 467                            unsigned long attrs)
 468 {
 469         struct scatterlist *s = sg, *start = sg, *dma = sg;
 470         unsigned int max = dma_get_max_seg_size(dev);
 471         unsigned int size = s->offset + s->length;
 472         unsigned int offset = s->offset;
 473         int count = 0, i;
 474
 475         for (i = 1; i < nr_elements; i++) {
 476                 s = sg_next(s);
 477
 478                 s->dma_address = DMA_ERROR_CODE;
 479                 s->dma_length = 0;
 480
 481                 if (s->offset || (size & ~PAGE_MASK) ||
 482                     size + s->length > max) {
 483                         if (__s390_dma_map_sg(dev, start, size,
 484                                               &dma->dma_address, dir))
 485                                 goto unmap;
 486
 487                         dma->dma_address += offset;
 488                         dma->dma_length = size - offset;
 489
 490                         size = offset = s->offset;
 491                         start = s;
 492                         dma = sg_next(dma);
 493                         count++;
 494                 }
 495                 size += s->length;
 496         }
 497         if (__s390_dma_map_sg(dev, start, size, &dma->dma_address, dir))
 498                 goto unmap;
 499
 500         dma->dma_address += offset;
 501         dma->dma_length = size - offset;
 502
 503         return count + 1;
 504 unmap:
 505         for_each_sg(sg, s, count, i)
 506                 s390_dma_unmap_pages(dev, sg_dma_address(s), sg_dma_len(s),
 507                                      dir, attrs);
 508
 509         return 0;
 510 }
 511
 512 static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 513                               int nr_elements, enum dma_data_direction dir,
 514                               unsigned long attrs)
 515 {
 516         struct scatterlist *s;
 517         int i;
 518
 519         for_each_sg(sg, s, nr_elements, i) {
 520                 if (s->dma_length)
 521                         s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
 522                                              dir, attrs);
 523                 s->dma_address = 0;
 524                 s->dma_length = 0;
 525         }
 526 }
 527
 528 int zpci_dma_init_device(struct zpci_dev *zdev)
 529 {
 530         int rc;
 531
 532         /*
 533          * At this point, if the device is part of an IOMMU domain, this would
 534          * be a strong hint towards a bug in the IOMMU API (common) code and/or
 535          * simultaneous access via IOMMU and DMA API. So let's issue a warning.
 536          */
 537         WARN_ON(zdev->s390_domain);
 538
 539         spin_lock_init(&zdev->iommu_bitmap_lock);
 540         spin_lock_init(&zdev->dma_table_lock);
 541
 542         zdev->dma_table = dma_alloc_cpu_table();
 543         if (!zdev->dma_table) {
 544                 rc = -ENOMEM;
 545                 goto out;
 546         }
 547
 548         /*
 549          * Restrict the iommu bitmap size to the minimum of the following:
 550          * - main memory size
 551          * - 3-level pagetable address limit minus start_dma offset
 552          * - DMA address range allowed by the hardware (clp query pci fn)
 553          *
 554          * Also set zdev->end_dma to the actual end address of the usable
 555          * range, instead of the theoretical maximum as reported by hardware.
 556          */
 557         zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
 558         zdev->iommu_size = min3((u64) high_memory,
 559                                 ZPCI_TABLE_SIZE_RT - zdev->start_dma,
 560                                 zdev->end_dma - zdev->start_dma + 1);
 561         zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1;
 562         zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
 563         zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
 564         if (!zdev->iommu_bitmap) {
 565                 rc = -ENOMEM;
 566                 goto free_dma_table;
 567         }
 568         if (!zdev->tlb_refresh && !s390_iommu_strict) {
 569                 zdev->lazy_bitmap = vzalloc(zdev->iommu_pages / 8);
 570                 if (!zdev->lazy_bitmap) {
 571                         rc = -ENOMEM;
 572                         goto free_bitmap;
 573                 }
 574
 575         }
 576         rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 577                                 (u64) zdev->dma_table);
 578         if (rc)
 579                 goto free_bitmap;
 580
 581         return 0;
 582 free_bitmap:
 583         vfree(zdev->iommu_bitmap);
 584         zdev->iommu_bitmap = NULL;
 585         vfree(zdev->lazy_bitmap);
 586         zdev->lazy_bitmap = NULL;
 587 free_dma_table:
 588         dma_free_cpu_table(zdev->dma_table);
 589         zdev->dma_table = NULL;
 590 out:
 591         return rc;
 592 }
 593
 594 void zpci_dma_exit_device(struct zpci_dev *zdev)
 595 {
 596         /*
 597          * At this point, if the device is part of an IOMMU domain, this would
 598          * be a strong hint towards a bug in the IOMMU API (common) code and/or
 599          * simultaneous access via IOMMU and DMA API. So let's issue a warning.
 600          */
 601         WARN_ON(zdev->s390_domain);
 602
 603         zpci_unregister_ioat(zdev, 0);
 604         dma_cleanup_tables(zdev->dma_table);
 605         zdev->dma_table = NULL;
 606         vfree(zdev->iommu_bitmap);
 607         zdev->iommu_bitmap = NULL;
 608         vfree(zdev->lazy_bitmap);
 609         zdev->lazy_bitmap = NULL;
 610
 611         zdev->next_bit = 0;
 612 }
 613
 614 static int __init dma_alloc_cpu_table_caches(void)
 615 {
 616         dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
 617                                         ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
 618                                         0, NULL);
 619         if (!dma_region_table_cache)
 620                 return -ENOMEM;
 621
 622         dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
 623                                         ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
 624                                         0, NULL);
 625         if (!dma_page_table_cache) {
 626                 kmem_cache_destroy(dma_region_table_cache);
 627                 return -ENOMEM;
 628         }
 629         return 0;
 630 }
 631
 632 int __init zpci_dma_init(void)
 633 {
 634         return dma_alloc_cpu_table_caches();
 635 }
 636
 637 void zpci_dma_exit(void)
 638 {
 639         kmem_cache_destroy(dma_page_table_cache);
 640         kmem_cache_destroy(dma_region_table_cache);
 641 }
 642
 643 #define PREALLOC_DMA_DEBUG_ENTRIES      (1 << 16)
 644
 645 static int __init dma_debug_do_init(void)
 646 {
 647         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 648         return 0;
 649 }
 650 fs_initcall(dma_debug_do_init);
 651
 652 struct dma_map_ops s390_pci_dma_ops = {
 653         .alloc          = s390_dma_alloc,
 654         .free           = s390_dma_free,
 655         .map_sg         = s390_dma_map_sg,
 656         .unmap_sg       = s390_dma_unmap_sg,
 657         .map_page       = s390_dma_map_pages,
 658         .unmap_page     = s390_dma_unmap_pages,
 659         /* if we support direct DMA this must be conditional */
 660         .is_phys        = 0,
 661         /* dma_supported is unconditionally true without a callback */
 662 };
 663 EXPORT_SYMBOL_GPL(s390_pci_dma_ops);
 664
 665 static int __init s390_iommu_setup(char *str)
 666 {
 667         if (!strncmp(str, "strict", 6))
 668                 s390_iommu_strict = 1;
 669         return 0;
 670 }
 671
 672 __setup("s390_iommu=", s390_iommu_setup);