linux/lib/swiotlb.c
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   1/*
   2 * Dynamic DMA mapping support.
   3 *
   4 * This implementation is a fallback for platforms that do not support
   5 * I/O TLBs (aka DMA address translation hardware).
   6 * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com>
   7 * Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com>
   8 * Copyright (C) 2000, 2003 Hewlett-Packard Co
   9 *      David Mosberger-Tang <davidm@hpl.hp.com>
  10 *
  11 * 03/05/07 davidm      Switch from PCI-DMA to generic device DMA API.
  12 * 00/12/13 davidm      Rename to swiotlb.c and add mark_clean() to avoid
  13 *                      unnecessary i-cache flushing.
  14 * 04/07/.. ak          Better overflow handling. Assorted fixes.
  15 * 05/09/10 linville    Add support for syncing ranges, support syncing for
  16 *                      DMA_BIDIRECTIONAL mappings, miscellaneous cleanup.
  17 * 08/12/11 beckyb      Add highmem support
  18 */
  19
  20#include <linux/cache.h>
  21#include <linux/dma-mapping.h>
  22#include <linux/mm.h>
  23#include <linux/module.h>
  24#include <linux/spinlock.h>
  25#include <linux/string.h>
  26#include <linux/swiotlb.h>
  27#include <linux/pfn.h>
  28#include <linux/types.h>
  29#include <linux/ctype.h>
  30#include <linux/highmem.h>
  31#include <linux/gfp.h>
  32
  33#include <asm/io.h>
  34#include <asm/dma.h>
  35#include <asm/scatterlist.h>
  36
  37#include <linux/init.h>
  38#include <linux/bootmem.h>
  39#include <linux/iommu-helper.h>
  40
  41#define OFFSET(val,align) ((unsigned long)      \
  42                           ( (val) & ( (align) - 1)))
  43
  44#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
  45
  46/*
  47 * Minimum IO TLB size to bother booting with.  Systems with mainly
  48 * 64bit capable cards will only lightly use the swiotlb.  If we can't
  49 * allocate a contiguous 1MB, we're probably in trouble anyway.
  50 */
  51#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
  52
  53int swiotlb_force;
  54
  55/*
  56 * Used to do a quick range check in swiotlb_tbl_unmap_single and
  57 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
  58 * API.
  59 */
  60static char *io_tlb_start, *io_tlb_end;
  61
  62/*
  63 * The number of IO TLB blocks (in groups of 64) between io_tlb_start and
  64 * io_tlb_end.  This is command line adjustable via setup_io_tlb_npages.
  65 */
  66static unsigned long io_tlb_nslabs;
  67
  68/*
  69 * When the IOMMU overflows we return a fallback buffer. This sets the size.
  70 */
  71static unsigned long io_tlb_overflow = 32*1024;
  72
  73static void *io_tlb_overflow_buffer;
  74
  75/*
  76 * This is a free list describing the number of free entries available from
  77 * each index
  78 */
  79static unsigned int *io_tlb_list;
  80static unsigned int io_tlb_index;
  81
  82/*
  83 * We need to save away the original address corresponding to a mapped entry
  84 * for the sync operations.
  85 */
  86static phys_addr_t *io_tlb_orig_addr;
  87
  88/*
  89 * Protect the above data structures in the map and unmap calls
  90 */
  91static DEFINE_SPINLOCK(io_tlb_lock);
  92
  93static int late_alloc;
  94
  95static int __init
  96setup_io_tlb_npages(char *str)
  97{
  98        if (isdigit(*str)) {
  99                io_tlb_nslabs = simple_strtoul(str, &str, 0);
 100                /* avoid tail segment of size < IO_TLB_SEGSIZE */
 101                io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
 102        }
 103        if (*str == ',')
 104                ++str;
 105        if (!strcmp(str, "force"))
 106                swiotlb_force = 1;
 107
 108        return 1;
 109}
 110__setup("swiotlb=", setup_io_tlb_npages);
 111/* make io_tlb_overflow tunable too? */
 112
 113unsigned long swioltb_nr_tbl(void)
 114{
 115        return io_tlb_nslabs;
 116}
 117
 118/* Note that this doesn't work with highmem page */
 119static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
 120                                      volatile void *address)
 121{
 122        return phys_to_dma(hwdev, virt_to_phys(address));
 123}
 124
 125void swiotlb_print_info(void)
 126{
 127        unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;
 128        phys_addr_t pstart, pend;
 129
 130        pstart = virt_to_phys(io_tlb_start);
 131        pend = virt_to_phys(io_tlb_end);
 132
 133        printk(KERN_INFO "Placing %luMB software IO TLB between %p - %p\n",
 134               bytes >> 20, io_tlb_start, io_tlb_end);
 135        printk(KERN_INFO "software IO TLB at phys %#llx - %#llx\n",
 136               (unsigned long long)pstart,
 137               (unsigned long long)pend);
 138}
 139
 140void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 141{
 142        unsigned long i, bytes;
 143
 144        bytes = nslabs << IO_TLB_SHIFT;
 145
 146        io_tlb_nslabs = nslabs;
 147        io_tlb_start = tlb;
 148        io_tlb_end = io_tlb_start + bytes;
 149
 150        /*
 151         * Allocate and initialize the free list array.  This array is used
 152         * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
 153         * between io_tlb_start and io_tlb_end.
 154         */
 155        io_tlb_list = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
 156        for (i = 0; i < io_tlb_nslabs; i++)
 157                io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
 158        io_tlb_index = 0;
 159        io_tlb_orig_addr = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
 160
 161        /*
 162         * Get the overflow emergency buffer
 163         */
 164        io_tlb_overflow_buffer = alloc_bootmem_low_pages(PAGE_ALIGN(io_tlb_overflow));
 165        if (!io_tlb_overflow_buffer)
 166                panic("Cannot allocate SWIOTLB overflow buffer!\n");
 167        if (verbose)
 168                swiotlb_print_info();
 169}
 170
 171/*
 172 * Statically reserve bounce buffer space and initialize bounce buffer data
 173 * structures for the software IO TLB used to implement the DMA API.
 174 */
 175void __init
 176swiotlb_init_with_default_size(size_t default_size, int verbose)
 177{
 178        unsigned long bytes;
 179
 180        if (!io_tlb_nslabs) {
 181                io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
 182                io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
 183        }
 184
 185        bytes = io_tlb_nslabs << IO_TLB_SHIFT;
 186
 187        /*
 188         * Get IO TLB memory from the low pages
 189         */
 190        io_tlb_start = alloc_bootmem_low_pages(PAGE_ALIGN(bytes));
 191        if (!io_tlb_start)
 192                panic("Cannot allocate SWIOTLB buffer");
 193
 194        swiotlb_init_with_tbl(io_tlb_start, io_tlb_nslabs, verbose);
 195}
 196
 197void __init
 198swiotlb_init(int verbose)
 199{
 200        swiotlb_init_with_default_size(64 * (1<<20), verbose);  /* default to 64MB */
 201}
 202
 203/*
 204 * Systems with larger DMA zones (those that don't support ISA) can
 205 * initialize the swiotlb later using the slab allocator if needed.
 206 * This should be just like above, but with some error catching.
 207 */
 208int
 209swiotlb_late_init_with_default_size(size_t default_size)
 210{
 211        unsigned long i, bytes, req_nslabs = io_tlb_nslabs;
 212        unsigned int order;
 213
 214        if (!io_tlb_nslabs) {
 215                io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
 216                io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
 217        }
 218
 219        /*
 220         * Get IO TLB memory from the low pages
 221         */
 222        order = get_order(io_tlb_nslabs << IO_TLB_SHIFT);
 223        io_tlb_nslabs = SLABS_PER_PAGE << order;
 224        bytes = io_tlb_nslabs << IO_TLB_SHIFT;
 225
 226        while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
 227                io_tlb_start = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
 228                                                        order);
 229                if (io_tlb_start)
 230                        break;
 231                order--;
 232        }
 233
 234        if (!io_tlb_start)
 235                goto cleanup1;
 236
 237        if (order != get_order(bytes)) {
 238                printk(KERN_WARNING "Warning: only able to allocate %ld MB "
 239                       "for software IO TLB\n", (PAGE_SIZE << order) >> 20);
 240                io_tlb_nslabs = SLABS_PER_PAGE << order;
 241                bytes = io_tlb_nslabs << IO_TLB_SHIFT;
 242        }
 243        io_tlb_end = io_tlb_start + bytes;
 244        memset(io_tlb_start, 0, bytes);
 245
 246        /*
 247         * Allocate and initialize the free list array.  This array is used
 248         * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
 249         * between io_tlb_start and io_tlb_end.
 250         */
 251        io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
 252                                      get_order(io_tlb_nslabs * sizeof(int)));
 253        if (!io_tlb_list)
 254                goto cleanup2;
 255
 256        for (i = 0; i < io_tlb_nslabs; i++)
 257                io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
 258        io_tlb_index = 0;
 259
 260        io_tlb_orig_addr = (phys_addr_t *)
 261                __get_free_pages(GFP_KERNEL,
 262                                 get_order(io_tlb_nslabs *
 263                                           sizeof(phys_addr_t)));
 264        if (!io_tlb_orig_addr)
 265                goto cleanup3;
 266
 267        memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(phys_addr_t));
 268
 269        /*
 270         * Get the overflow emergency buffer
 271         */
 272        io_tlb_overflow_buffer = (void *)__get_free_pages(GFP_DMA,
 273                                                  get_order(io_tlb_overflow));
 274        if (!io_tlb_overflow_buffer)
 275                goto cleanup4;
 276
 277        swiotlb_print_info();
 278
 279        late_alloc = 1;
 280
 281        return 0;
 282
 283cleanup4:
 284        free_pages((unsigned long)io_tlb_orig_addr,
 285                   get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
 286        io_tlb_orig_addr = NULL;
 287cleanup3:
 288        free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
 289                                                         sizeof(int)));
 290        io_tlb_list = NULL;
 291cleanup2:
 292        io_tlb_end = NULL;
 293        free_pages((unsigned long)io_tlb_start, order);
 294        io_tlb_start = NULL;
 295cleanup1:
 296        io_tlb_nslabs = req_nslabs;
 297        return -ENOMEM;
 298}
 299
 300void __init swiotlb_free(void)
 301{
 302        if (!io_tlb_overflow_buffer)
 303                return;
 304
 305        if (late_alloc) {
 306                free_pages((unsigned long)io_tlb_overflow_buffer,
 307                           get_order(io_tlb_overflow));
 308                free_pages((unsigned long)io_tlb_orig_addr,
 309                           get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
 310                free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
 311                                                                 sizeof(int)));
 312                free_pages((unsigned long)io_tlb_start,
 313                           get_order(io_tlb_nslabs << IO_TLB_SHIFT));
 314        } else {
 315                free_bootmem_late(__pa(io_tlb_overflow_buffer),
 316                                  PAGE_ALIGN(io_tlb_overflow));
 317                free_bootmem_late(__pa(io_tlb_orig_addr),
 318                                  PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
 319                free_bootmem_late(__pa(io_tlb_list),
 320                                  PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
 321                free_bootmem_late(__pa(io_tlb_start),
 322                                  PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
 323        }
 324}
 325
 326static int is_swiotlb_buffer(phys_addr_t paddr)
 327{
 328        return paddr >= virt_to_phys(io_tlb_start) &&
 329                paddr < virt_to_phys(io_tlb_end);
 330}
 331
 332/*
 333 * Bounce: copy the swiotlb buffer back to the original dma location
 334 */
 335void swiotlb_bounce(phys_addr_t phys, char *dma_addr, size_t size,
 336                    enum dma_data_direction dir)
 337{
 338        unsigned long pfn = PFN_DOWN(phys);
 339
 340        if (PageHighMem(pfn_to_page(pfn))) {
 341                /* The buffer does not have a mapping.  Map it in and copy */
 342                unsigned int offset = phys & ~PAGE_MASK;
 343                char *buffer;
 344                unsigned int sz = 0;
 345                unsigned long flags;
 346
 347                while (size) {
 348                        sz = min_t(size_t, PAGE_SIZE - offset, size);
 349
 350                        local_irq_save(flags);
 351                        buffer = kmap_atomic(pfn_to_page(pfn),
 352                                             KM_BOUNCE_READ);
 353                        if (dir == DMA_TO_DEVICE)
 354                                memcpy(dma_addr, buffer + offset, sz);
 355                        else
 356                                memcpy(buffer + offset, dma_addr, sz);
 357                        kunmap_atomic(buffer, KM_BOUNCE_READ);
 358                        local_irq_restore(flags);
 359
 360                        size -= sz;
 361                        pfn++;
 362                        dma_addr += sz;
 363                        offset = 0;
 364                }
 365        } else {
 366                if (dir == DMA_TO_DEVICE)
 367                        memcpy(dma_addr, phys_to_virt(phys), size);
 368                else
 369                        memcpy(phys_to_virt(phys), dma_addr, size);
 370        }
 371}
 372EXPORT_SYMBOL_GPL(swiotlb_bounce);
 373
 374void *swiotlb_tbl_map_single(struct device *hwdev, dma_addr_t tbl_dma_addr,
 375                             phys_addr_t phys, size_t size,
 376                             enum dma_data_direction dir)
 377{
 378        unsigned long flags;
 379        char *dma_addr;
 380        unsigned int nslots, stride, index, wrap;
 381        int i;
 382        unsigned long mask;
 383        unsigned long offset_slots;
 384        unsigned long max_slots;
 385
 386        mask = dma_get_seg_boundary(hwdev);
 387
 388        tbl_dma_addr &= mask;
 389
 390        offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
 391
 392        /*
 393         * Carefully handle integer overflow which can occur when mask == ~0UL.
 394         */
 395        max_slots = mask + 1
 396                    ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
 397                    : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
 398
 399        /*
 400         * For mappings greater than a page, we limit the stride (and
 401         * hence alignment) to a page size.
 402         */
 403        nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
 404        if (size > PAGE_SIZE)
 405                stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
 406        else
 407                stride = 1;
 408
 409        BUG_ON(!nslots);
 410
 411        /*
 412         * Find suitable number of IO TLB entries size that will fit this
 413         * request and allocate a buffer from that IO TLB pool.
 414         */
 415        spin_lock_irqsave(&io_tlb_lock, flags);
 416        index = ALIGN(io_tlb_index, stride);
 417        if (index >= io_tlb_nslabs)
 418                index = 0;
 419        wrap = index;
 420
 421        do {
 422                while (iommu_is_span_boundary(index, nslots, offset_slots,
 423                                              max_slots)) {
 424                        index += stride;
 425                        if (index >= io_tlb_nslabs)
 426                                index = 0;
 427                        if (index == wrap)
 428                                goto not_found;
 429                }
 430
 431                /*
 432                 * If we find a slot that indicates we have 'nslots' number of
 433                 * contiguous buffers, we allocate the buffers from that slot
 434                 * and mark the entries as '0' indicating unavailable.
 435                 */
 436                if (io_tlb_list[index] >= nslots) {
 437                        int count = 0;
 438
 439                        for (i = index; i < (int) (index + nslots); i++)
 440                                io_tlb_list[i] = 0;
 441                        for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--)
 442                                io_tlb_list[i] = ++count;
 443                        dma_addr = io_tlb_start + (index << IO_TLB_SHIFT);
 444
 445                        /*
 446                         * Update the indices to avoid searching in the next
 447                         * round.
 448                         */
 449                        io_tlb_index = ((index + nslots) < io_tlb_nslabs
 450                                        ? (index + nslots) : 0);
 451
 452                        goto found;
 453                }
 454                index += stride;
 455                if (index >= io_tlb_nslabs)
 456                        index = 0;
 457        } while (index != wrap);
 458
 459not_found:
 460        spin_unlock_irqrestore(&io_tlb_lock, flags);
 461        return NULL;
 462found:
 463        spin_unlock_irqrestore(&io_tlb_lock, flags);
 464
 465        /*
 466         * Save away the mapping from the original address to the DMA address.
 467         * This is needed when we sync the memory.  Then we sync the buffer if
 468         * needed.
 469         */
 470        for (i = 0; i < nslots; i++)
 471                io_tlb_orig_addr[index+i] = phys + (i << IO_TLB_SHIFT);
 472        if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
 473                swiotlb_bounce(phys, dma_addr, size, DMA_TO_DEVICE);
 474
 475        return dma_addr;
 476}
 477EXPORT_SYMBOL_GPL(swiotlb_tbl_map_single);
 478
 479/*
 480 * Allocates bounce buffer and returns its kernel virtual address.
 481 */
 482
 483static void *
 484map_single(struct device *hwdev, phys_addr_t phys, size_t size,
 485           enum dma_data_direction dir)
 486{
 487        dma_addr_t start_dma_addr = swiotlb_virt_to_bus(hwdev, io_tlb_start);
 488
 489        return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir);
 490}
 491
 492/*
 493 * dma_addr is the kernel virtual address of the bounce buffer to unmap.
 494 */
 495void
 496swiotlb_tbl_unmap_single(struct device *hwdev, char *dma_addr, size_t size,
 497                        enum dma_data_direction dir)
 498{
 499        unsigned long flags;
 500        int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
 501        int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
 502        phys_addr_t phys = io_tlb_orig_addr[index];
 503
 504        /*
 505         * First, sync the memory before unmapping the entry
 506         */
 507        if (phys && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
 508                swiotlb_bounce(phys, dma_addr, size, DMA_FROM_DEVICE);
 509
 510        /*
 511         * Return the buffer to the free list by setting the corresponding
 512         * entries to indicate the number of contiguous entries available.
 513         * While returning the entries to the free list, we merge the entries
 514         * with slots below and above the pool being returned.
 515         */
 516        spin_lock_irqsave(&io_tlb_lock, flags);
 517        {
 518                count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
 519                         io_tlb_list[index + nslots] : 0);
 520                /*
 521                 * Step 1: return the slots to the free list, merging the
 522                 * slots with superceeding slots
 523                 */
 524                for (i = index + nslots - 1; i >= index; i--)
 525                        io_tlb_list[i] = ++count;
 526                /*
 527                 * Step 2: merge the returned slots with the preceding slots,
 528                 * if available (non zero)
 529                 */
 530                for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
 531                        io_tlb_list[i] = ++count;
 532        }
 533        spin_unlock_irqrestore(&io_tlb_lock, flags);
 534}
 535EXPORT_SYMBOL_GPL(swiotlb_tbl_unmap_single);
 536
 537void
 538swiotlb_tbl_sync_single(struct device *hwdev, char *dma_addr, size_t size,
 539                        enum dma_data_direction dir,
 540                        enum dma_sync_target target)
 541{
 542        int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
 543        phys_addr_t phys = io_tlb_orig_addr[index];
 544
 545        phys += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));
 546
 547        switch (target) {
 548        case SYNC_FOR_CPU:
 549                if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
 550                        swiotlb_bounce(phys, dma_addr, size, DMA_FROM_DEVICE);
 551                else
 552                        BUG_ON(dir != DMA_TO_DEVICE);
 553                break;
 554        case SYNC_FOR_DEVICE:
 555                if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
 556                        swiotlb_bounce(phys, dma_addr, size, DMA_TO_DEVICE);
 557                else
 558                        BUG_ON(dir != DMA_FROM_DEVICE);
 559                break;
 560        default:
 561                BUG();
 562        }
 563}
 564EXPORT_SYMBOL_GPL(swiotlb_tbl_sync_single);
 565
 566void *
 567swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 568                       dma_addr_t *dma_handle, gfp_t flags)
 569{
 570        dma_addr_t dev_addr;
 571        void *ret;
 572        int order = get_order(size);
 573        u64 dma_mask = DMA_BIT_MASK(32);
 574
 575        if (hwdev && hwdev->coherent_dma_mask)
 576                dma_mask = hwdev->coherent_dma_mask;
 577
 578        ret = (void *)__get_free_pages(flags, order);
 579        if (ret && swiotlb_virt_to_bus(hwdev, ret) + size - 1 > dma_mask) {
 580                /*
 581                 * The allocated memory isn't reachable by the device.
 582                 */
 583                free_pages((unsigned long) ret, order);
 584                ret = NULL;
 585        }
 586        if (!ret) {
 587                /*
 588                 * We are either out of memory or the device can't DMA to
 589                 * GFP_DMA memory; fall back on map_single(), which
 590                 * will grab memory from the lowest available address range.
 591                 */
 592                ret = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
 593                if (!ret)
 594                        return NULL;
 595        }
 596
 597        memset(ret, 0, size);
 598        dev_addr = swiotlb_virt_to_bus(hwdev, ret);
 599
 600        /* Confirm address can be DMA'd by device */
 601        if (dev_addr + size - 1 > dma_mask) {
 602                printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n",
 603                       (unsigned long long)dma_mask,
 604                       (unsigned long long)dev_addr);
 605
 606                /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
 607                swiotlb_tbl_unmap_single(hwdev, ret, size, DMA_TO_DEVICE);
 608                return NULL;
 609        }
 610        *dma_handle = dev_addr;
 611        return ret;
 612}
 613EXPORT_SYMBOL(swiotlb_alloc_coherent);
 614
 615void
 616swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
 617                      dma_addr_t dev_addr)
 618{
 619        phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
 620
 621        WARN_ON(irqs_disabled());
 622        if (!is_swiotlb_buffer(paddr))
 623                free_pages((unsigned long)vaddr, get_order(size));
 624        else
 625                /* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */
 626                swiotlb_tbl_unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE);
 627}
 628EXPORT_SYMBOL(swiotlb_free_coherent);
 629
 630static void
 631swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir,
 632             int do_panic)
 633{
 634        /*
 635         * Ran out of IOMMU space for this operation. This is very bad.
 636         * Unfortunately the drivers cannot handle this operation properly.
 637         * unless they check for dma_mapping_error (most don't)
 638         * When the mapping is small enough return a static buffer to limit
 639         * the damage, or panic when the transfer is too big.
 640         */
 641        printk(KERN_ERR "DMA: Out of SW-IOMMU space for %zu bytes at "
 642               "device %s\n", size, dev ? dev_name(dev) : "?");
 643
 644        if (size <= io_tlb_overflow || !do_panic)
 645                return;
 646
 647        if (dir == DMA_BIDIRECTIONAL)
 648                panic("DMA: Random memory could be DMA accessed\n");
 649        if (dir == DMA_FROM_DEVICE)
 650                panic("DMA: Random memory could be DMA written\n");
 651        if (dir == DMA_TO_DEVICE)
 652                panic("DMA: Random memory could be DMA read\n");
 653}
 654
 655/*
 656 * Map a single buffer of the indicated size for DMA in streaming mode.  The
 657 * physical address to use is returned.
 658 *
 659 * Once the device is given the dma address, the device owns this memory until
 660 * either swiotlb_unmap_page or swiotlb_dma_sync_single is performed.
 661 */
 662dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
 663                            unsigned long offset, size_t size,
 664                            enum dma_data_direction dir,
 665                            struct dma_attrs *attrs)
 666{
 667        phys_addr_t phys = page_to_phys(page) + offset;
 668        dma_addr_t dev_addr = phys_to_dma(dev, phys);
 669        void *map;
 670
 671        BUG_ON(dir == DMA_NONE);
 672        /*
 673         * If the address happens to be in the device's DMA window,
 674         * we can safely return the device addr and not worry about bounce
 675         * buffering it.
 676         */
 677        if (dma_capable(dev, dev_addr, size) && !swiotlb_force)
 678                return dev_addr;
 679
 680        /*
 681         * Oh well, have to allocate and map a bounce buffer.
 682         */
 683        map = map_single(dev, phys, size, dir);
 684        if (!map) {
 685                swiotlb_full(dev, size, dir, 1);
 686                map = io_tlb_overflow_buffer;
 687        }
 688
 689        dev_addr = swiotlb_virt_to_bus(dev, map);
 690
 691        /*
 692         * Ensure that the address returned is DMA'ble
 693         */
 694        if (!dma_capable(dev, dev_addr, size)) {
 695                swiotlb_tbl_unmap_single(dev, map, size, dir);
 696                dev_addr = swiotlb_virt_to_bus(dev, io_tlb_overflow_buffer);
 697        }
 698
 699        return dev_addr;
 700}
 701EXPORT_SYMBOL_GPL(swiotlb_map_page);
 702
 703/*
 704 * Unmap a single streaming mode DMA translation.  The dma_addr and size must
 705 * match what was provided for in a previous swiotlb_map_page call.  All
 706 * other usages are undefined.
 707 *
 708 * After this call, reads by the cpu to the buffer are guaranteed to see
 709 * whatever the device wrote there.
 710 */
 711static void unmap_single(struct device *hwdev, dma_addr_t dev_addr,
 712                         size_t size, enum dma_data_direction dir)
 713{
 714        phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
 715
 716        BUG_ON(dir == DMA_NONE);
 717
 718        if (is_swiotlb_buffer(paddr)) {
 719                swiotlb_tbl_unmap_single(hwdev, phys_to_virt(paddr), size, dir);
 720                return;
 721        }
 722
 723        if (dir != DMA_FROM_DEVICE)
 724                return;
 725
 726        /*
 727         * phys_to_virt doesn't work with hihgmem page but we could
 728         * call dma_mark_clean() with hihgmem page here. However, we
 729         * are fine since dma_mark_clean() is null on POWERPC. We can
 730         * make dma_mark_clean() take a physical address if necessary.
 731         */
 732        dma_mark_clean(phys_to_virt(paddr), size);
 733}
 734
 735void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
 736                        size_t size, enum dma_data_direction dir,
 737                        struct dma_attrs *attrs)
 738{
 739        unmap_single(hwdev, dev_addr, size, dir);
 740}
 741EXPORT_SYMBOL_GPL(swiotlb_unmap_page);
 742
 743/*
 744 * Make physical memory consistent for a single streaming mode DMA translation
 745 * after a transfer.
 746 *
 747 * If you perform a swiotlb_map_page() but wish to interrogate the buffer
 748 * using the cpu, yet do not wish to teardown the dma mapping, you must
 749 * call this function before doing so.  At the next point you give the dma
 750 * address back to the card, you must first perform a
 751 * swiotlb_dma_sync_for_device, and then the device again owns the buffer
 752 */
 753static void
 754swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
 755                    size_t size, enum dma_data_direction dir,
 756                    enum dma_sync_target target)
 757{
 758        phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
 759
 760        BUG_ON(dir == DMA_NONE);
 761
 762        if (is_swiotlb_buffer(paddr)) {
 763                swiotlb_tbl_sync_single(hwdev, phys_to_virt(paddr), size, dir,
 764                                       target);
 765                return;
 766        }
 767
 768        if (dir != DMA_FROM_DEVICE)
 769                return;
 770
 771        dma_mark_clean(phys_to_virt(paddr), size);
 772}
 773
 774void
 775swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
 776                            size_t size, enum dma_data_direction dir)
 777{
 778        swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
 779}
 780EXPORT_SYMBOL(swiotlb_sync_single_for_cpu);
 781
 782void
 783swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
 784                               size_t size, enum dma_data_direction dir)
 785{
 786        swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
 787}
 788EXPORT_SYMBOL(swiotlb_sync_single_for_device);
 789
 790/*
 791 * Map a set of buffers described by scatterlist in streaming mode for DMA.
 792 * This is the scatter-gather version of the above swiotlb_map_page
 793 * interface.  Here the scatter gather list elements are each tagged with the
 794 * appropriate dma address and length.  They are obtained via
 795 * sg_dma_{address,length}(SG).
 796 *
 797 * NOTE: An implementation may be able to use a smaller number of
 798 *       DMA address/length pairs than there are SG table elements.
 799 *       (for example via virtual mapping capabilities)
 800 *       The routine returns the number of addr/length pairs actually
 801 *       used, at most nents.
 802 *
 803 * Device ownership issues as mentioned above for swiotlb_map_page are the
 804 * same here.
 805 */
 806int
 807swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
 808                     enum dma_data_direction dir, struct dma_attrs *attrs)
 809{
 810        struct scatterlist *sg;
 811        int i;
 812
 813        BUG_ON(dir == DMA_NONE);
 814
 815        for_each_sg(sgl, sg, nelems, i) {
 816                phys_addr_t paddr = sg_phys(sg);
 817                dma_addr_t dev_addr = phys_to_dma(hwdev, paddr);
 818
 819                if (swiotlb_force ||
 820                    !dma_capable(hwdev, dev_addr, sg->length)) {
 821                        void *map = map_single(hwdev, sg_phys(sg),
 822                                               sg->length, dir);
 823                        if (!map) {
 824                                /* Don't panic here, we expect map_sg users
 825                                   to do proper error handling. */
 826                                swiotlb_full(hwdev, sg->length, dir, 0);
 827                                swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
 828                                                       attrs);
 829                                sgl[0].dma_length = 0;
 830                                return 0;
 831                        }
 832                        sg->dma_address = swiotlb_virt_to_bus(hwdev, map);
 833                } else
 834                        sg->dma_address = dev_addr;
 835                sg->dma_length = sg->length;
 836        }
 837        return nelems;
 838}
 839EXPORT_SYMBOL(swiotlb_map_sg_attrs);
 840
 841int
 842swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
 843               enum dma_data_direction dir)
 844{
 845        return swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL);
 846}
 847EXPORT_SYMBOL(swiotlb_map_sg);
 848
 849/*
 850 * Unmap a set of streaming mode DMA translations.  Again, cpu read rules
 851 * concerning calls here are the same as for swiotlb_unmap_page() above.
 852 */
 853void
 854swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 855                       int nelems, enum dma_data_direction dir, struct dma_attrs *attrs)
 856{
 857        struct scatterlist *sg;
 858        int i;
 859
 860        BUG_ON(dir == DMA_NONE);
 861
 862        for_each_sg(sgl, sg, nelems, i)
 863                unmap_single(hwdev, sg->dma_address, sg->dma_length, dir);
 864
 865}
 866EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
 867
 868void
 869swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
 870                 enum dma_data_direction dir)
 871{
 872        return swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL);
 873}
 874EXPORT_SYMBOL(swiotlb_unmap_sg);
 875
 876/*
 877 * Make physical memory consistent for a set of streaming mode DMA translations
 878 * after a transfer.
 879 *
 880 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
 881 * and usage.
 882 */
 883static void
 884swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
 885                int nelems, enum dma_data_direction dir,
 886                enum dma_sync_target target)
 887{
 888        struct scatterlist *sg;
 889        int i;
 890
 891        for_each_sg(sgl, sg, nelems, i)
 892                swiotlb_sync_single(hwdev, sg->dma_address,
 893                                    sg->dma_length, dir, target);
 894}
 895
 896void
 897swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
 898                        int nelems, enum dma_data_direction dir)
 899{
 900        swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
 901}
 902EXPORT_SYMBOL(swiotlb_sync_sg_for_cpu);
 903
 904void
 905swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
 906                           int nelems, enum dma_data_direction dir)
 907{
 908        swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
 909}
 910EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
 911
 912int
 913swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
 914{
 915        return (dma_addr == swiotlb_virt_to_bus(hwdev, io_tlb_overflow_buffer));
 916}
 917EXPORT_SYMBOL(swiotlb_dma_mapping_error);
 918
 919/*
 920 * Return whether the given device DMA address mask can be supported
 921 * properly.  For example, if your device can only drive the low 24-bits
 922 * during bus mastering, then you would pass 0x00ffffff as the mask to
 923 * this function.
 924 */
 925int
 926swiotlb_dma_supported(struct device *hwdev, u64 mask)
 927{
 928        return swiotlb_virt_to_bus(hwdev, io_tlb_end - 1) <= mask;
 929}
 930EXPORT_SYMBOL(swiotlb_dma_supported);
 931
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