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         dma_addr_t start_dma_addr = dma_addr;
 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 no_refresh;
 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         /*
 163          * With zdev->tlb_refresh == 0, rpcit is not required to establish new
 164          * translations when previously invalid translation-table entries are
 165          * validated. With lazy unmap, it also is skipped for previously valid
 166          * entries, but a global rpcit is then required before any address can
 167          * be re-used, i.e. after each iommu bitmap wrap-around.
 168          */
 169         if (!zdev->tlb_refresh &&
 170                         (!s390_iommu_strict ||
 171                         ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)))
 172                 goto no_refresh;
 173
 174         rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr,
 175                                 nr_pages * PAGE_SIZE);
 176 undo_cpu_trans:
 177         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 178                 flags = ZPCI_PTE_INVALID;
 179                 while (i-- > 0) {
 180                         page_addr -= PAGE_SIZE;
 181                         dma_addr -= PAGE_SIZE;
 182                         entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
 183                         if (!entry)
 184                                 break;
 185                         dma_update_cpu_trans(entry, page_addr, flags);
 186                 }
 187         }
 188
 189 no_refresh:
 190         spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
 191         return rc;
 192 }
 193
 194 void dma_free_seg_table(unsigned long entry)
 195 {
 196         unsigned long *sto = get_rt_sto(entry);
 197         int sx;
 198
 199         for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
 200                 if (reg_entry_isvalid(sto[sx]))
 201                         dma_free_page_table(get_st_pto(sto[sx]));
 202
 203         dma_free_cpu_table(sto);
 204 }
 205
 206 void dma_cleanup_tables(unsigned long *table)
 207 {
 208         int rtx;
 209
 210         if (!table)
 211                 return;
 212
 213         for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
 214                 if (reg_entry_isvalid(table[rtx]))
 215                         dma_free_seg_table(table[rtx]);
 216
 217         dma_free_cpu_table(table);
 218 }
 219
 220 static unsigned long __dma_alloc_iommu(struct device *dev,
 221                                        unsigned long start, int size)
 222 {
 223         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 224         unsigned long boundary_size;
 225
 226         boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
 227                               PAGE_SIZE) >> PAGE_SHIFT;
 228         return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
 229                                 start, size, 0, boundary_size, 0);
 230 }
 231
 232 static unsigned long dma_alloc_iommu(struct device *dev, int size)
 233 {
 234         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 235         unsigned long offset, flags;
 236         int wrap = 0;
 237
 238         spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 239         offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
 240         if (offset == -1) {
 241                 /* wrap-around */
 242                 offset = __dma_alloc_iommu(dev, 0, size);
 243                 wrap = 1;
 244         }
 245
 246         if (offset != -1) {
 247                 zdev->next_bit = offset + size;
 248                 if (!zdev->tlb_refresh && !s390_iommu_strict && wrap)
 249                         /* global flush after wrap-around with lazy unmap */
 250                         zpci_refresh_global(zdev);
 251         }
 252         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 253         return offset;
 254 }
 255
 256 static void dma_free_iommu(struct device *dev, unsigned long offset, int size)
 257 {
 258         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 259         unsigned long flags;
 260
 261         spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 262         if (!zdev->iommu_bitmap)
 263                 goto out;
 264         bitmap_clear(zdev->iommu_bitmap, offset, size);
 265         /*
 266          * Lazy flush for unmap: need to move next_bit to avoid address re-use
 267          * until wrap-around.
 268          */
 269         if (!s390_iommu_strict && offset >= zdev->next_bit)
 270                 zdev->next_bit = offset + size;
 271 out:
 272         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 273 }
 274
 275 static inline void zpci_err_dma(unsigned long rc, unsigned long addr)
 276 {
 277         struct {
 278                 unsigned long rc;
 279                 unsigned long addr;
 280         } __packed data = {rc, addr};
 281
 282         zpci_err_hex(&data, sizeof(data));
 283 }
 284
 285 static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
 286                                      unsigned long offset, size_t size,
 287                                      enum dma_data_direction direction,
 288                                      struct dma_attrs *attrs)
 289 {
 290         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 291         unsigned long nr_pages, iommu_page_index;
 292         unsigned long pa = page_to_phys(page) + offset;
 293         int flags = ZPCI_PTE_VALID;
 294         dma_addr_t dma_addr;
 295         int ret;
 296
 297         /* This rounds up number of pages based on size and offset */
 298         nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
 299         iommu_page_index = dma_alloc_iommu(dev, nr_pages);
 300         if (iommu_page_index == -1) {
 301                 ret = -ENOSPC;
 302                 goto out_err;
 303         }
 304
 305         /* Use rounded up size */
 306         size = nr_pages * PAGE_SIZE;
 307
 308         dma_addr = zdev->start_dma + iommu_page_index * PAGE_SIZE;
 309         if (dma_addr + size > zdev->end_dma) {
 310                 ret = -ERANGE;
 311                 goto out_free;
 312         }
 313
 314         if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
 315                 flags |= ZPCI_TABLE_PROTECTED;
 316
 317         ret = dma_update_trans(zdev, pa, dma_addr, size, flags);
 318         if (ret)
 319                 goto out_free;
 320
 321         atomic64_add(nr_pages, &zdev->mapped_pages);
 322         return dma_addr + (offset & ~PAGE_MASK);
 323
 324 out_free:
 325         dma_free_iommu(dev, iommu_page_index, nr_pages);
 326 out_err:
 327         zpci_err("map error:\n");
 328         zpci_err_dma(ret, pa);
 329         return DMA_ERROR_CODE;
 330 }
 331
 332 static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
 333                                  size_t size, enum dma_data_direction direction,
 334                                  struct dma_attrs *attrs)
 335 {
 336         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 337         unsigned long iommu_page_index;
 338         int npages, ret;
 339
 340         npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
 341         dma_addr = dma_addr & PAGE_MASK;
 342         ret = dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
 343                                ZPCI_PTE_INVALID);
 344         if (ret) {
 345                 zpci_err("unmap error:\n");
 346                 zpci_err_dma(ret, dma_addr);
 347                 return;
 348         }
 349
 350         atomic64_add(npages, &zdev->unmapped_pages);
 351         iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
 352         dma_free_iommu(dev, iommu_page_index, npages);
 353 }
 354
 355 static void *s390_dma_alloc(struct device *dev, size_t size,
 356                             dma_addr_t *dma_handle, gfp_t flag,
 357                             struct dma_attrs *attrs)
 358 {
 359         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 360         struct page *page;
 361         unsigned long pa;
 362         dma_addr_t map;
 363
 364         size = PAGE_ALIGN(size);
 365         page = alloc_pages(flag, get_order(size));
 366         if (!page)
 367                 return NULL;
 368
 369         pa = page_to_phys(page);
 370         memset((void *) pa, 0, size);
 371
 372         map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, NULL);
 373         if (dma_mapping_error(dev, map)) {
 374                 free_pages(pa, get_order(size));
 375                 return NULL;
 376         }
 377
 378         atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
 379         if (dma_handle)
 380                 *dma_handle = map;
 381         return (void *) pa;
 382 }
 383
 384 static void s390_dma_free(struct device *dev, size_t size,
 385                           void *pa, dma_addr_t dma_handle,
 386                           struct dma_attrs *attrs)
 387 {
 388         struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 389
 390         size = PAGE_ALIGN(size);
 391         atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
 392         s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, NULL);
 393         free_pages((unsigned long) pa, get_order(size));
 394 }
 395
 396 static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 397                            int nr_elements, enum dma_data_direction dir,
 398                            struct dma_attrs *attrs)
 399 {
 400         int mapped_elements = 0;
 401         struct scatterlist *s;
 402         int i;
 403
 404         for_each_sg(sg, s, nr_elements, i) {
 405                 struct page *page = sg_page(s);
 406                 s->dma_address = s390_dma_map_pages(dev, page, s->offset,
 407                                                     s->length, dir, NULL);
 408                 if (!dma_mapping_error(dev, s->dma_address)) {
 409                         s->dma_length = s->length;
 410                         mapped_elements++;
 411                 } else
 412                         goto unmap;
 413         }
 414 out:
 415         return mapped_elements;
 416
 417 unmap:
 418         for_each_sg(sg, s, mapped_elements, i) {
 419                 if (s->dma_address)
 420                         s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
 421                                              dir, NULL);
 422                 s->dma_address = 0;
 423                 s->dma_length = 0;
 424         }
 425         mapped_elements = 0;
 426         goto out;
 427 }
 428
 429 static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 430                               int nr_elements, enum dma_data_direction dir,
 431                               struct dma_attrs *attrs)
 432 {
 433         struct scatterlist *s;
 434         int i;
 435
 436         for_each_sg(sg, s, nr_elements, i) {
 437                 s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir, NULL);
 438                 s->dma_address = 0;
 439                 s->dma_length = 0;
 440         }
 441 }
 442
 443 int zpci_dma_init_device(struct zpci_dev *zdev)
 444 {
 445         int rc;
 446
 447         /*
 448          * At this point, if the device is part of an IOMMU domain, this would
 449          * be a strong hint towards a bug in the IOMMU API (common) code and/or
 450          * simultaneous access via IOMMU and DMA API. So let's issue a warning.
 451          */
 452         WARN_ON(zdev->s390_domain);
 453
 454         spin_lock_init(&zdev->iommu_bitmap_lock);
 455         spin_lock_init(&zdev->dma_table_lock);
 456
 457         zdev->dma_table = dma_alloc_cpu_table();
 458         if (!zdev->dma_table) {
 459                 rc = -ENOMEM;
 460                 goto out;
 461         }
 462
 463         /*
 464          * Restrict the iommu bitmap size to the minimum of the following:
 465          * - main memory size
 466          * - 3-level pagetable address limit minus start_dma offset
 467          * - DMA address range allowed by the hardware (clp query pci fn)
 468          *
 469          * Also set zdev->end_dma to the actual end address of the usable
 470          * range, instead of the theoretical maximum as reported by hardware.
 471          */
 472         zdev->iommu_size = min3((u64) high_memory,
 473                                 ZPCI_TABLE_SIZE_RT - zdev->start_dma,
 474                                 zdev->end_dma - zdev->start_dma + 1);
 475         zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1;
 476         zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
 477         zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
 478         if (!zdev->iommu_bitmap) {
 479                 rc = -ENOMEM;
 480                 goto free_dma_table;
 481         }
 482
 483         rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 484                                 (u64) zdev->dma_table);
 485         if (rc)
 486                 goto free_bitmap;
 487
 488         return 0;
 489 free_bitmap:
 490         vfree(zdev->iommu_bitmap);
 491         zdev->iommu_bitmap = NULL;
 492 free_dma_table:
 493         dma_free_cpu_table(zdev->dma_table);
 494         zdev->dma_table = NULL;
 495 out:
 496         return rc;
 497 }
 498
 499 void zpci_dma_exit_device(struct zpci_dev *zdev)
 500 {
 501         /*
 502          * At this point, if the device is part of an IOMMU domain, this would
 503          * be a strong hint towards a bug in the IOMMU API (common) code and/or
 504          * simultaneous access via IOMMU and DMA API. So let's issue a warning.
 505          */
 506         WARN_ON(zdev->s390_domain);
 507
 508         zpci_unregister_ioat(zdev, 0);
 509         dma_cleanup_tables(zdev->dma_table);
 510         zdev->dma_table = NULL;
 511         vfree(zdev->iommu_bitmap);
 512         zdev->iommu_bitmap = NULL;
 513         zdev->next_bit = 0;
 514 }
 515
 516 static int __init dma_alloc_cpu_table_caches(void)
 517 {
 518         dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
 519                                         ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
 520                                         0, NULL);
 521         if (!dma_region_table_cache)
 522                 return -ENOMEM;
 523
 524         dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
 525                                         ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
 526                                         0, NULL);
 527         if (!dma_page_table_cache) {
 528                 kmem_cache_destroy(dma_region_table_cache);
 529                 return -ENOMEM;
 530         }
 531         return 0;
 532 }
 533
 534 int __init zpci_dma_init(void)
 535 {
 536         return dma_alloc_cpu_table_caches();
 537 }
 538
 539 void zpci_dma_exit(void)
 540 {
 541         kmem_cache_destroy(dma_page_table_cache);
 542         kmem_cache_destroy(dma_region_table_cache);
 543 }
 544
 545 #define PREALLOC_DMA_DEBUG_ENTRIES      (1 << 16)
 546
 547 static int __init dma_debug_do_init(void)
 548 {
 549         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 550         return 0;
 551 }
 552 fs_initcall(dma_debug_do_init);
 553
 554 struct dma_map_ops s390_pci_dma_ops = {
 555         .alloc          = s390_dma_alloc,
 556         .free           = s390_dma_free,
 557         .map_sg         = s390_dma_map_sg,
 558         .unmap_sg       = s390_dma_unmap_sg,
 559         .map_page       = s390_dma_map_pages,
 560         .unmap_page     = s390_dma_unmap_pages,
 561         /* if we support direct DMA this must be conditional */
 562         .is_phys        = 0,
 563         /* dma_supported is unconditionally true without a callback */
 564 };
 565 EXPORT_SYMBOL_GPL(s390_pci_dma_ops);
 566
 567 static int __init s390_iommu_setup(char *str)
 568 {
 569         if (!strncmp(str, "strict", 6))
 570                 s390_iommu_strict = 1;
 571         return 0;
 572 }
 573
 574 __setup("s390_iommu=", s390_iommu_setup);