kernel/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 static 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 | ZPCI_TABLE_PROTECTED;
  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 | ZPCI_TABLE_PROTECTED;
  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 static 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 static void dma_update_cpu_trans(struct zpci_dev *zdev, void *page_addr,
 118                                  dma_addr_t dma_addr, int flags)
 119 {
 120         unsigned long *entry;
 121
 122         entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr);
 123         if (!entry) {
 124                 WARN_ON_ONCE(1);
 125                 return;
 126         }
 127
 128         if (flags & ZPCI_PTE_INVALID) {
 129                 invalidate_pt_entry(entry);
 130                 return;
 131         } else {
 132                 set_pt_pfaa(entry, page_addr);
 133                 validate_pt_entry(entry);
 134         }
 135
 136         if (flags & ZPCI_TABLE_PROTECTED)
 137                 entry_set_protected(entry);
 138         else
 139                 entry_clr_protected(entry);
 140 }
 141
 142 static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
 143                             dma_addr_t dma_addr, size_t size, int flags)
 144 {
 145         unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 146         u8 *page_addr = (u8 *) (pa & PAGE_MASK);
 147         dma_addr_t start_dma_addr = dma_addr;
 148         unsigned long irq_flags;
 149         int i, rc = 0;
 150
 151         if (!nr_pages)
 152                 return -EINVAL;
 153
 154         spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
 155         if (!zdev->dma_table)
 156                 goto no_refresh;
 157
 158         for (i = 0; i < nr_pages; i++) {
 159                 dma_update_cpu_trans(zdev, page_addr, dma_addr, flags);
 160                 page_addr += PAGE_SIZE;
 161                 dma_addr += PAGE_SIZE;
 162         }
 163
 164         /*
 165          * With zdev->tlb_refresh == 0, rpcit is not required to establish new
 166          * translations when previously invalid translation-table entries are
 167          * validated. With lazy unmap, it also is skipped for previously valid
 168          * entries, but a global rpcit is then required before any address can
 169          * be re-used, i.e. after each iommu bitmap wrap-around.
 170          */
 171         if (!zdev->tlb_refresh &&
 172                         (!s390_iommu_strict ||
 173                         ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)))
 174                 goto no_refresh;
 175
 176         rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr,
 177                                 nr_pages * PAGE_SIZE);
 178
 179 no_refresh:
 180         spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
 181         return rc;
 182 }
 183
 184 static void dma_free_seg_table(unsigned long entry)
 185 {
 186         unsigned long *sto = get_rt_sto(entry);
 187         int sx;
 188
 189         for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
 190                 if (reg_entry_isvalid(sto[sx]))
 191                         dma_free_page_table(get_st_pto(sto[sx]));
 192
 193         dma_free_cpu_table(sto);
 194 }
 195
 196 static void dma_cleanup_tables(struct zpci_dev *zdev)
 197 {
 198         unsigned long *table;
 199         int rtx;
 200
 201         if (!zdev || !zdev->dma_table)
 202                 return;
 203
 204         table = zdev->dma_table;
 205         for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
 206                 if (reg_entry_isvalid(table[rtx]))
 207                         dma_free_seg_table(table[rtx]);
 208
 209         dma_free_cpu_table(table);
 210         zdev->dma_table = NULL;
 211 }
 212
 213 static unsigned long __dma_alloc_iommu(struct zpci_dev *zdev,
 214                                        unsigned long start, int size)
 215 {
 216         unsigned long boundary_size;
 217
 218         boundary_size = ALIGN(dma_get_seg_boundary(&zdev->pdev->dev) + 1,
 219                               PAGE_SIZE) >> PAGE_SHIFT;
 220         return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
 221                                 start, size, 0, boundary_size, 0);
 222 }
 223
 224 static unsigned long dma_alloc_iommu(struct zpci_dev *zdev, int size)
 225 {
 226         unsigned long offset, flags;
 227         int wrap = 0;
 228
 229         spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 230         offset = __dma_alloc_iommu(zdev, zdev->next_bit, size);
 231         if (offset == -1) {
 232                 /* wrap-around */
 233                 offset = __dma_alloc_iommu(zdev, 0, size);
 234                 wrap = 1;
 235         }
 236
 237         if (offset != -1) {
 238                 zdev->next_bit = offset + size;
 239                 if (!zdev->tlb_refresh && !s390_iommu_strict && wrap)
 240                         /* global flush after wrap-around with lazy unmap */
 241                         zpci_refresh_global(zdev);
 242         }
 243         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 244         return offset;
 245 }
 246
 247 static void dma_free_iommu(struct zpci_dev *zdev, unsigned long offset, int size)
 248 {
 249         unsigned long flags;
 250
 251         spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
 252         if (!zdev->iommu_bitmap)
 253                 goto out;
 254         bitmap_clear(zdev->iommu_bitmap, offset, size);
 255         /*
 256          * Lazy flush for unmap: need to move next_bit to avoid address re-use
 257          * until wrap-around.
 258          */
 259         if (!s390_iommu_strict && offset >= zdev->next_bit)
 260                 zdev->next_bit = offset + size;
 261 out:
 262         spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
 263 }
 264
 265 int dma_set_mask(struct device *dev, u64 mask)
 266 {
 267         if (!dev->dma_mask || !dma_supported(dev, mask))
 268                 return -EIO;
 269
 270         *dev->dma_mask = mask;
 271         return 0;
 272 }
 273 EXPORT_SYMBOL_GPL(dma_set_mask);
 274
 275 static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
 276                                      unsigned long offset, size_t size,
 277                                      enum dma_data_direction direction,
 278                                      struct dma_attrs *attrs)
 279 {
 280         struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
 281         unsigned long nr_pages, iommu_page_index;
 282         unsigned long pa = page_to_phys(page) + offset;
 283         int flags = ZPCI_PTE_VALID;
 284         dma_addr_t dma_addr;
 285
 286         /* This rounds up number of pages based on size and offset */
 287         nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
 288         iommu_page_index = dma_alloc_iommu(zdev, nr_pages);
 289         if (iommu_page_index == -1)
 290                 goto out_err;
 291
 292         /* Use rounded up size */
 293         size = nr_pages * PAGE_SIZE;
 294
 295         dma_addr = zdev->start_dma + iommu_page_index * PAGE_SIZE;
 296         if (dma_addr + size > zdev->end_dma)
 297                 goto out_free;
 298
 299         if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
 300                 flags |= ZPCI_TABLE_PROTECTED;
 301
 302         if (!dma_update_trans(zdev, pa, dma_addr, size, flags)) {
 303                 atomic64_add(nr_pages, &zdev->mapped_pages);
 304                 return dma_addr + (offset & ~PAGE_MASK);
 305         }
 306
 307 out_free:
 308         dma_free_iommu(zdev, iommu_page_index, nr_pages);
 309 out_err:
 310         zpci_err("map error:\n");
 311         zpci_err_hex(&pa, sizeof(pa));
 312         return DMA_ERROR_CODE;
 313 }
 314
 315 static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
 316                                  size_t size, enum dma_data_direction direction,
 317                                  struct dma_attrs *attrs)
 318 {
 319         struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
 320         unsigned long iommu_page_index;
 321         int npages;
 322
 323         npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
 324         dma_addr = dma_addr & PAGE_MASK;
 325         if (dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
 326                              ZPCI_TABLE_PROTECTED | ZPCI_PTE_INVALID)) {
 327                 zpci_err("unmap error:\n");
 328                 zpci_err_hex(&dma_addr, sizeof(dma_addr));
 329         }
 330
 331         atomic64_add(npages, &zdev->unmapped_pages);
 332         iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
 333         dma_free_iommu(zdev, iommu_page_index, npages);
 334 }
 335
 336 static void *s390_dma_alloc(struct device *dev, size_t size,
 337                             dma_addr_t *dma_handle, gfp_t flag,
 338                             struct dma_attrs *attrs)
 339 {
 340         struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
 341         struct page *page;
 342         unsigned long pa;
 343         dma_addr_t map;
 344
 345         size = PAGE_ALIGN(size);
 346         page = alloc_pages(flag, get_order(size));
 347         if (!page)
 348                 return NULL;
 349
 350         pa = page_to_phys(page);
 351         memset((void *) pa, 0, size);
 352
 353         map = s390_dma_map_pages(dev, page, pa % PAGE_SIZE,
 354                                  size, DMA_BIDIRECTIONAL, NULL);
 355         if (dma_mapping_error(dev, map)) {
 356                 free_pages(pa, get_order(size));
 357                 return NULL;
 358         }
 359
 360         atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
 361         if (dma_handle)
 362                 *dma_handle = map;
 363         return (void *) pa;
 364 }
 365
 366 static void s390_dma_free(struct device *dev, size_t size,
 367                           void *pa, dma_addr_t dma_handle,
 368                           struct dma_attrs *attrs)
 369 {
 370         struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
 371
 372         size = PAGE_ALIGN(size);
 373         atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
 374         s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, NULL);
 375         free_pages((unsigned long) pa, get_order(size));
 376 }
 377
 378 static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 379                            int nr_elements, enum dma_data_direction dir,
 380                            struct dma_attrs *attrs)
 381 {
 382         int mapped_elements = 0;
 383         struct scatterlist *s;
 384         int i;
 385
 386         for_each_sg(sg, s, nr_elements, i) {
 387                 struct page *page = sg_page(s);
 388                 s->dma_address = s390_dma_map_pages(dev, page, s->offset,
 389                                                     s->length, dir, NULL);
 390                 if (!dma_mapping_error(dev, s->dma_address)) {
 391                         s->dma_length = s->length;
 392                         mapped_elements++;
 393                 } else
 394                         goto unmap;
 395         }
 396 out:
 397         return mapped_elements;
 398
 399 unmap:
 400         for_each_sg(sg, s, mapped_elements, i) {
 401                 if (s->dma_address)
 402                         s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
 403                                              dir, NULL);
 404                 s->dma_address = 0;
 405                 s->dma_length = 0;
 406         }
 407         mapped_elements = 0;
 408         goto out;
 409 }
 410
 411 static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 412                               int nr_elements, enum dma_data_direction dir,
 413                               struct dma_attrs *attrs)
 414 {
 415         struct scatterlist *s;
 416         int i;
 417
 418         for_each_sg(sg, s, nr_elements, i) {
 419                 s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir, NULL);
 420                 s->dma_address = 0;
 421                 s->dma_length = 0;
 422         }
 423 }
 424
 425 int zpci_dma_init_device(struct zpci_dev *zdev)
 426 {
 427         int rc;
 428
 429         spin_lock_init(&zdev->iommu_bitmap_lock);
 430         spin_lock_init(&zdev->dma_table_lock);
 431
 432         zdev->dma_table = dma_alloc_cpu_table();
 433         if (!zdev->dma_table) {
 434                 rc = -ENOMEM;
 435                 goto out_clean;
 436         }
 437
 438         zdev->iommu_size = (unsigned long) high_memory - PAGE_OFFSET;
 439         zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
 440         zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
 441         if (!zdev->iommu_bitmap) {
 442                 rc = -ENOMEM;
 443                 goto out_reg;
 444         }
 445
 446         rc = zpci_register_ioat(zdev,
 447                                 0,
 448                                 zdev->start_dma + PAGE_OFFSET,
 449                                 zdev->start_dma + zdev->iommu_size - 1,
 450                                 (u64) zdev->dma_table);
 451         if (rc)
 452                 goto out_reg;
 453         return 0;
 454
 455 out_reg:
 456         dma_free_cpu_table(zdev->dma_table);
 457 out_clean:
 458         return rc;
 459 }
 460
 461 void zpci_dma_exit_device(struct zpci_dev *zdev)
 462 {
 463         zpci_unregister_ioat(zdev, 0);
 464         dma_cleanup_tables(zdev);
 465         vfree(zdev->iommu_bitmap);
 466         zdev->iommu_bitmap = NULL;
 467         zdev->next_bit = 0;
 468 }
 469
 470 static int __init dma_alloc_cpu_table_caches(void)
 471 {
 472         dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
 473                                         ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
 474                                         0, NULL);
 475         if (!dma_region_table_cache)
 476                 return -ENOMEM;
 477
 478         dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
 479                                         ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
 480                                         0, NULL);
 481         if (!dma_page_table_cache) {
 482                 kmem_cache_destroy(dma_region_table_cache);
 483                 return -ENOMEM;
 484         }
 485         return 0;
 486 }
 487
 488 int __init zpci_dma_init(void)
 489 {
 490         return dma_alloc_cpu_table_caches();
 491 }
 492
 493 void zpci_dma_exit(void)
 494 {
 495         kmem_cache_destroy(dma_page_table_cache);
 496         kmem_cache_destroy(dma_region_table_cache);
 497 }
 498
 499 #define PREALLOC_DMA_DEBUG_ENTRIES      (1 << 16)
 500
 501 static int __init dma_debug_do_init(void)
 502 {
 503         dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 504         return 0;
 505 }
 506 fs_initcall(dma_debug_do_init);
 507
 508 struct dma_map_ops s390_dma_ops = {
 509         .alloc          = s390_dma_alloc,
 510         .free           = s390_dma_free,
 511         .map_sg         = s390_dma_map_sg,
 512         .unmap_sg       = s390_dma_unmap_sg,
 513         .map_page       = s390_dma_map_pages,
 514         .unmap_page     = s390_dma_unmap_pages,
 515         /* if we support direct DMA this must be conditional */
 516         .is_phys        = 0,
 517         /* dma_supported is unconditionally true without a callback */
 518 };
 519 EXPORT_SYMBOL_GPL(s390_dma_ops);
 520
 521 static int __init s390_iommu_setup(char *str)
 522 {
 523         if (!strncmp(str, "strict", 6))
 524                 s390_iommu_strict = 1;
 525         return 0;
 526 }
 527
 528 __setup("s390_iommu=", s390_iommu_setup);