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