arch/s390/pci/pci_dma.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright IBM Corp. 2012
   4  *
   5  * Author(s):
   6  *   Jan Glauber <jang@linux.vnet.ibm.com>
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/slab.h>
  11 #include <linux/export.h>
  12 #include <linux/iommu-helper.h>
  13 #include <linux/dma-mapping.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/pci.h>
  16 #include <asm/pci_dma.h>
  17
  18 #define S390_MAPPING_ERROR              (~(dma_addr_t) 0x0)
  19
  20 static struct kmem_cache *dma_region_table_cache;
  21 static struct kmem_cache *dma_page_table_cache;
  22 static int s390_iommu_strict;
  23
  24 static int zpci_refresh_global(struct zpci_dev *zdev)
  25 {
  26         return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma,
  27                                   zdev->iommu_pages * PAGE_SIZE);
  28 }
  29
  30 unsigned long *dma_alloc_cpu_table(void)
  31 {
  32         unsigned long *table, *entry;
  33
  34         table = kmem_cache_alloc(dma_region_table_cache, GFP_ATOMIC);
  35         if (!table)
  36                 return NULL;
  37
  38         for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
  39                 *entry = ZPCI_TABLE_INVALID;
  40         return table;
  41 }
  42
  43 static void dma_free_cpu_table(void *table)
  44 {
  45         kmem_cache_free(dma_region_table_cache, table);
  46 }
  47
  48 static unsigned long *dma_alloc_page_table(void)
  49 {
  50         unsigned long *table, *entry;
  51
  52         table = kmem_cache_alloc(dma_page_table_cache, GFP_ATOMIC);
  53         if (!table)
  54                 return NULL;
  55
  56         for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
  57                 *entry = ZPCI_PTE_INVALID;
  58         return table;
  59 }
  60
  61 static void dma_free_page_table(void *table)
  62 {
  63         kmem_cache_free(dma_page_table_cache, table);
  64 }
  65
  66 static unsigned long *dma_get_seg_table_origin(unsigned long *entry)
  67 {
  68         unsigned long *sto;
  69
  70         if (reg_entry_isvalid(*entry))
  71                 sto = get_rt_sto(*entry);
  72         else {
  73                 sto = dma_alloc_cpu_table();
  74                 if (!sto)
  75                         return NULL;
  76
  77                 set_rt_sto(entry, sto);
  78                 validate_rt_entry(entry);
  79                 entry_clr_protected(entry);
  80         }
  81         return sto;
  82 }
  83
  84 static unsigned long *dma_get_page_table_origin(unsigned long *entry)
  85 {
  86         unsigned long *pto;
  87
  88         if (reg_entry_isvalid(*entry))
  89                 pto = get_st_pto(*entry);
  90         else {
  91                 pto = dma_alloc_page_table();
  92                 if (!pto)
  93                         return NULL;
  94                 set_st_pto(entry, pto);
  95                 validate_st_entry(entry);
  96                 entry_clr_protected(entry);
  97         }
  98         return pto;
  99 }
 100
 101 unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr)
 102 {
 103         unsigned long *sto, *pto;
 104         unsigned int rtx, sx, px;
 105
 106         rtx = calc_rtx(dma_addr);
 107         sto = dma_get_seg_table_origin(&rto[rtx]);
 108         if (!sto)
 109                 return NULL;
 110
 111         sx = calc_sx(dma_addr);
 112         pto = dma_get_page_table_origin(&sto[sx]);
 113         if (!pto)
 114                 return NULL;
 115
 116         px = calc_px(dma_addr);
 117         return &pto[px];
 118 }
 119
 120 void dma_update_cpu_trans(unsigned long *entry, void *page_addr, int flags)
 121 {
 122         if (flags & ZPCI_PTE_INVALID) {
 123                 invalidate_pt_entry(entry);
 124         } else {
 125                 set_pt_pfaa(entry, page_addr);
 126                 validate_pt_entry(entry);
 127         }
 128
 129         if (flags & ZPCI_TABLE_PROTECTED)
 130                 entry_set_protected(entry);
 131         else
 132                 entry_clr_protected(entry);
 133 }
 134
 135 static int __dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
 136                               dma_addr_t dma_addr, size_t size, int flags)
 137 {
 138         unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 139         u8 *page_addr = (u8 *) (pa & PAGE_MASK);
 140         unsigned long irq_flags;
 141         unsigned long *entry;
 142         int i, rc = 0;
 143
 144         if (!nr_pages)
 145                 return -EINVAL;
 146
 147         spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
 148         if (!zdev->dma_table) {
 149                 rc = -EINVAL;
 150                 goto out_unlock;
 151         }
 152
 153         for (i = 0; i < nr_pages; i++) {
 154                 entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
 155                 if (!entry) {
 156                         rc = -ENOMEM;
 157                         goto undo_cpu_trans;
 158                 }
 159                 dma_update_cpu_trans(entry, page_addr, flags);
 160                 page_addr += PAGE_SIZE;
 161                 dma_addr += PAGE_SIZE;
 162         }
 163
 164 undo_cpu_trans:
 165         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 166                 flags = ZPCI_PTE_INVALID;
 167                 while (i-- > 0) {
 168                         page_addr -= PAGE_SIZE;
 169                         dma_addr -= PAGE_SIZE;
 170                         entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
 171                         if (!entry)
 172                                 break;
 173                         dma_update_cpu_trans(entry, page_addr, flags);
 174                 }
 175         }
 176 out_unlock:
 177         spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
 178         return rc;
 179 }
 180
 181 static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
 182                            size_t size, int flags)
 183 {
 184         /*
 185          * With zdev->tlb_refresh == 0, rpcit is not required to establish new
 186          * translations when previously invalid translation-table entries are
 187          * validated. With lazy unmap, rpcit is skipped for previously valid
 188          * entries, but a global rpcit is then required before any address can
 189          * be re-used, i.e. after each iommu bitmap wrap-around.
 190          */
 191         if ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID) {
 192                 if (!zdev->tlb_refresh)
 193                         return 0;
 194         } else {
 195                 if (!s390_iommu_strict)
 196                         return 0;
 197         }
 198
 199         return zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
 200                                   PAGE_ALIGN(size));
 201 }
 202
 203 static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
 204                             dma_addr_t dma_addr, size_t size, int flags)
 205 {
 206         int rc;
 207
 208         rc = __dma_update_trans(zdev, pa, dma_addr, size, flags);
 209         if (rc)
 210                 return rc;
 211
 212         rc = __dma_purge_tlb(zdev, dma_addr, size, flags);
 213         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
 214                 __dma_update_trans(zdev, pa, dma_addr, size, ZPCI_PTE_INVALID);
 215
 216         return rc;
 217 }
 218
 219 void dma_free_seg_table(unsigned long entry)
 220 {
 221         unsigned long *sto = get_rt_sto(entry);
 222         int sx;
 223
 224         for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
 225                 if (reg_entry_isvalid(sto[sx]))
 226                         dma_free_page_table(get_st_pto(sto[sx]));
 227
 228         dma_free_cpu_table(sto);
 229 }
 230
 231 void dma_cleanup_tables(unsigned long *table)
 232 {
 233         int rtx;
 234
 235         if (!table)
 236                 return;
 237
 238         for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
 239                 if (reg_entry_isvalid(table[rtx]))
 240                         dma_free_seg_table(table[rtx]);
 241
 242         dma_free_cpu_table(table);
 243 }
 244
 245 static unsigned long __dma_alloc_iommu(struct device *dev,
 246                                        unsigned long start, int size)
 247 {
 248         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 249         unsigned long boundary_size;
 250
 251         boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
 252                               PAGE_SIZE) >> PAGE_SHIFT;
 253         return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
 254                                 start, size, zdev->start_dma >> PAGE_SHIFT,
 255                                 boundary_size, 0);
 256 }
 257
 258 static dma_addr_t dma_alloc_address(struct device *dev, int size)
 259 {
 260         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 261         unsigned long offset, flags;
 262
 263         spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 264         offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
 265         if (offset == -1) {
 266                 if (!s390_iommu_strict) {
 267                         /* global flush before DMA addresses are reused */
 268                         if (zpci_refresh_global(zdev))
 269                                 goto out_error;
 270
 271                         bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
 272                                       zdev->lazy_bitmap, zdev->iommu_pages);
 273                         bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
 274                 }
 275                 /* wrap-around */
 276                 offset = __dma_alloc_iommu(dev, 0, size);
 277                 if (offset == -1)
 278                         goto out_error;
 279         }
 280         zdev->next_bit = offset + size;
 281         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 282
 283         return zdev->start_dma + offset * PAGE_SIZE;
 284
 285 out_error:
 286         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 287         return S390_MAPPING_ERROR;
 288 }
 289
 290 static void dma_free_address(struct device *dev, dma_addr_t dma_addr, int size)
 291 {
 292         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 293         unsigned long flags, offset;
 294
 295         offset = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
 296
 297         spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 298         if (!zdev->iommu_bitmap)
 299                 goto out;
 300
 301         if (s390_iommu_strict)
 302                 bitmap_clear(zdev->iommu_bitmap, offset, size);
 303         else
 304                 bitmap_set(zdev->lazy_bitmap, offset, size);
 305
 306 out:
 307         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 308 }
 309
 310 static inline void zpci_err_dma(unsigned long rc, unsigned long addr)
 311 {
 312         struct {
 313                 unsigned long rc;
 314                 unsigned long addr;
 315         } __packed data = {rc, addr};
 316
 317         zpci_err_hex(&data, sizeof(data));
 318 }
 319
 320 static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
 321                                      unsigned long offset, size_t size,
 322                                      enum dma_data_direction direction,
 323                                      unsigned long attrs)
 324 {
 325         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 326         unsigned long pa = page_to_phys(page) + offset;
 327         int flags = ZPCI_PTE_VALID;
 328         unsigned long nr_pages;
 329         dma_addr_t dma_addr;
 330         int ret;
 331
 332         /* This rounds up number of pages based on size and offset */
 333         nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
 334         dma_addr = dma_alloc_address(dev, nr_pages);
 335         if (dma_addr == S390_MAPPING_ERROR) {
 336                 ret = -ENOSPC;
 337                 goto out_err;
 338         }
 339
 340         /* Use rounded up size */
 341         size = nr_pages * PAGE_SIZE;
 342
 343         if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
 344                 flags |= ZPCI_TABLE_PROTECTED;
 345
 346         ret = dma_update_trans(zdev, pa, dma_addr, size, flags);
 347         if (ret)
 348                 goto out_free;
 349
 350         atomic64_add(nr_pages, &zdev->mapped_pages);
 351         return dma_addr + (offset & ~PAGE_MASK);
 352
 353 out_free:
 354         dma_free_address(dev, dma_addr, nr_pages);
 355 out_err:
 356         zpci_err("map error:\n");
 357         zpci_err_dma(ret, pa);
 358         return S390_MAPPING_ERROR;
 359 }
 360
 361 static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
 362                                  size_t size, enum dma_data_direction direction,
 363                                  unsigned long attrs)
 364 {
 365         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 366         int npages, ret;
 367
 368         npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
 369         dma_addr = dma_addr & PAGE_MASK;
 370         ret = dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
 371                                ZPCI_PTE_INVALID);
 372         if (ret) {
 373                 zpci_err("unmap error:\n");
 374                 zpci_err_dma(ret, dma_addr);
 375                 return;
 376         }
 377
 378         atomic64_add(npages, &zdev->unmapped_pages);
 379         dma_free_address(dev, dma_addr, npages);
 380 }
 381
 382 static void *s390_dma_alloc(struct device *dev, size_t size,
 383                             dma_addr_t *dma_handle, gfp_t flag,
 384                             unsigned long attrs)
 385 {
 386         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 387         struct page *page;
 388         unsigned long pa;
 389         dma_addr_t map;
 390
 391         size = PAGE_ALIGN(size);
 392         page = alloc_pages(flag, get_order(size));
 393         if (!page)
 394                 return NULL;
 395
 396         pa = page_to_phys(page);
 397         map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
 398         if (dma_mapping_error(dev, map)) {
 399                 free_pages(pa, get_order(size));
 400                 return NULL;
 401         }
 402
 403         atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
 404         if (dma_handle)
 405                 *dma_handle = map;
 406         return (void *) pa;
 407 }
 408
 409 static void s390_dma_free(struct device *dev, size_t size,
 410                           void *pa, dma_addr_t dma_handle,
 411                           unsigned long attrs)
 412 {
 413         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 414
 415         size = PAGE_ALIGN(size);
 416         atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
 417         s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, 0);
 418         free_pages((unsigned long) pa, get_order(size));
 419 }
 420
 421 /* Map a segment into a contiguous dma address area */
 422 static int __s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 423                              size_t size, dma_addr_t *handle,
 424                              enum dma_data_direction dir)
 425 {
 426         unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 427         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 428         dma_addr_t dma_addr_base, dma_addr;
 429         int flags = ZPCI_PTE_VALID;
 430         struct scatterlist *s;
 431         unsigned long pa = 0;
 432         int ret;
 433
 434         dma_addr_base = dma_alloc_address(dev, nr_pages);
 435         if (dma_addr_base == S390_MAPPING_ERROR)
 436                 return -ENOMEM;
 437
 438         dma_addr = dma_addr_base;
 439         if (dir == DMA_NONE || dir == DMA_TO_DEVICE)
 440                 flags |= ZPCI_TABLE_PROTECTED;
 441
 442         for (s = sg; dma_addr < dma_addr_base + size; s = sg_next(s)) {
 443                 pa = page_to_phys(sg_page(s));
 444                 ret = __dma_update_trans(zdev, pa, dma_addr,
 445                                          s->offset + s->length, flags);
 446                 if (ret)
 447                         goto unmap;
 448
 449                 dma_addr += s->offset + s->length;
 450         }
 451         ret = __dma_purge_tlb(zdev, dma_addr_base, size, flags);
 452         if (ret)
 453                 goto unmap;
 454
 455         *handle = dma_addr_base;
 456         atomic64_add(nr_pages, &zdev->mapped_pages);
 457
 458         return ret;
 459
 460 unmap:
 461         dma_update_trans(zdev, 0, dma_addr_base, dma_addr - dma_addr_base,
 462                          ZPCI_PTE_INVALID);
 463         dma_free_address(dev, dma_addr_base, nr_pages);
 464         zpci_err("map error:\n");
 465         zpci_err_dma(ret, pa);
 466         return ret;
 467 }
 468
 469 static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 470                            int nr_elements, enum dma_data_direction dir,
 471                            unsigned long attrs)
 472 {
 473         struct scatterlist *s = sg, *start = sg, *dma = sg;
 474         unsigned int max = dma_get_max_seg_size(dev);
 475         unsigned int size = s->offset + s->length;
 476         unsigned int offset = s->offset;
 477         int count = 0, i;
 478
 479         for (i = 1; i < nr_elements; i++) {
 480                 s = sg_next(s);
 481
 482                 s->dma_address = S390_MAPPING_ERROR;
 483                 s->dma_length = 0;
 484
 485                 if (s->offset || (size & ~PAGE_MASK) ||
 486                     size + s->length > max) {
 487                         if (__s390_dma_map_sg(dev, start, size,
 488                                               &dma->dma_address, dir))
 489                                 goto unmap;
 490
 491                         dma->dma_address += offset;
 492                         dma->dma_length = size - offset;
 493
 494                         size = offset = s->offset;
 495                         start = s;
 496                         dma = sg_next(dma);
 497                         count++;
 498                 }
 499                 size += s->length;
 500         }
 501         if (__s390_dma_map_sg(dev, start, size, &dma->dma_address, dir))
 502                 goto unmap;
 503
 504         dma->dma_address += offset;
 505         dma->dma_length = size - offset;
 506
 507         return count + 1;
 508 unmap:
 509         for_each_sg(sg, s, count, i)
 510                 s390_dma_unmap_pages(dev, sg_dma_address(s), sg_dma_len(s),
 511                                      dir, attrs);
 512
 513         return 0;
 514 }
 515
 516 static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 517                               int nr_elements, enum dma_data_direction dir,
 518                               unsigned long attrs)
 519 {
 520         struct scatterlist *s;
 521         int i;
 522
 523         for_each_sg(sg, s, nr_elements, i) {
 524                 if (s->dma_length)
 525                         s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
 526                                              dir, attrs);
 527                 s->dma_address = 0;
 528                 s->dma_length = 0;
 529         }
 530 }
 531
 532 static int s390_mapping_error(struct device *dev, dma_addr_t dma_addr)
 533 {
 534         return dma_addr == S390_MAPPING_ERROR;
 535 }
 536
 537 int zpci_dma_init_device(struct zpci_dev *zdev)
 538 {
 539         int rc;
 540
 541         /*
 542          * At this point, if the device is part of an IOMMU domain, this would
 543          * be a strong hint towards a bug in the IOMMU API (common) code and/or
 544          * simultaneous access via IOMMU and DMA API. So let's issue a warning.
 545          */
 546         WARN_ON(zdev->s390_domain);
 547
 548         spin_lock_init(&zdev->iommu_bitmap_lock);
 549         spin_lock_init(&zdev->dma_table_lock);
 550
 551         zdev->dma_table = dma_alloc_cpu_table();
 552         if (!zdev->dma_table) {
 553                 rc = -ENOMEM;
 554                 goto out;
 555         }
 556
 557         /*
 558          * Restrict the iommu bitmap size to the minimum of the following:
 559          * - main memory size
 560          * - 3-level pagetable address limit minus start_dma offset
 561          * - DMA address range allowed by the hardware (clp query pci fn)
 562          *
 563          * Also set zdev->end_dma to the actual end address of the usable
 564          * range, instead of the theoretical maximum as reported by hardware.
 565          */
 566         zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
 567         zdev->iommu_size = min3((u64) high_memory,
 568                                 ZPCI_TABLE_SIZE_RT - zdev->start_dma,
 569                                 zdev->end_dma - zdev->start_dma + 1);
 570         zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1;
 571         zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
 572         zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
 573         if (!zdev->iommu_bitmap) {
 574                 rc = -ENOMEM;
 575                 goto free_dma_table;
 576         }
 577         if (!s390_iommu_strict) {
 578                 zdev->lazy_bitmap = vzalloc(zdev->iommu_pages / 8);
 579                 if (!zdev->lazy_bitmap) {
 580                         rc = -ENOMEM;
 581                         goto free_bitmap;
 582                 }
 583
 584         }
 585         rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 586                                 (u64) zdev->dma_table);
 587         if (rc)
 588                 goto free_bitmap;
 589
 590         return 0;
 591 free_bitmap:
 592         vfree(zdev->iommu_bitmap);
 593         zdev->iommu_bitmap = NULL;
 594         vfree(zdev->lazy_bitmap);
 595         zdev->lazy_bitmap = NULL;
 596 free_dma_table:
 597         dma_free_cpu_table(zdev->dma_table);
 598         zdev->dma_table = NULL;
 599 out:
 600         return rc;
 601 }
 602
 603 void zpci_dma_exit_device(struct zpci_dev *zdev)
 604 {
 605         /*
 606          * At this point, if the device is part of an IOMMU domain, this would
 607          * be a strong hint towards a bug in the IOMMU API (common) code and/or
 608          * simultaneous access via IOMMU and DMA API. So let's issue a warning.
 609          */
 610         WARN_ON(zdev->s390_domain);
 611
 612         if (zpci_unregister_ioat(zdev, 0))
 613                 return;
 614
 615         dma_cleanup_tables(zdev->dma_table);
 616         zdev->dma_table = NULL;
 617         vfree(zdev->iommu_bitmap);
 618         zdev->iommu_bitmap = NULL;
 619         vfree(zdev->lazy_bitmap);
 620         zdev->lazy_bitmap = NULL;
 621
 622         zdev->next_bit = 0;
 623 }
 624
 625 static int __init dma_alloc_cpu_table_caches(void)
 626 {
 627         dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
 628                                         ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
 629                                         0, NULL);
 630         if (!dma_region_table_cache)
 631                 return -ENOMEM;
 632
 633         dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
 634                                         ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
 635                                         0, NULL);
 636         if (!dma_page_table_cache) {
 637                 kmem_cache_destroy(dma_region_table_cache);
 638                 return -ENOMEM;
 639         }
 640         return 0;
 641 }
 642
 643 int __init zpci_dma_init(void)
 644 {
 645         return dma_alloc_cpu_table_caches();
 646 }
 647
 648 void zpci_dma_exit(void)
 649 {
 650         kmem_cache_destroy(dma_page_table_cache);
 651         kmem_cache_destroy(dma_region_table_cache);
 652 }
 653
 654 #define PREALLOC_DMA_DEBUG_ENTRIES      (1 << 16)
 655
 656 static int __init dma_debug_do_init(void)
 657 {
 658         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 659         return 0;
 660 }
 661 fs_initcall(dma_debug_do_init);
 662
 663 const struct dma_map_ops s390_pci_dma_ops = {
 664         .alloc          = s390_dma_alloc,
 665         .free           = s390_dma_free,
 666         .map_sg         = s390_dma_map_sg,
 667         .unmap_sg       = s390_dma_unmap_sg,
 668         .map_page       = s390_dma_map_pages,
 669         .unmap_page     = s390_dma_unmap_pages,
 670         .mapping_error  = s390_mapping_error,
 671         /* if we support direct DMA this must be conditional */
 672         .is_phys        = 0,
 673         /* dma_supported is unconditionally true without a callback */
 674 };
 675 EXPORT_SYMBOL_GPL(s390_pci_dma_ops);
 676
 677 static int __init s390_iommu_setup(char *str)
 678 {
 679         if (!strncmp(str, "strict", 6))
 680                 s390_iommu_strict = 1;
 681         return 0;
 682 }
 683
 684 __setup("s390_iommu=", s390_iommu_setup);