linux/include/linux/dma-mapping.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_DMA_MAPPING_H
   3#define _LINUX_DMA_MAPPING_H
   4
   5#include <linux/sizes.h>
   6#include <linux/string.h>
   7#include <linux/device.h>
   8#include <linux/err.h>
   9#include <linux/dma-direction.h>
  10#include <linux/scatterlist.h>
  11#include <linux/bug.h>
  12#include <linux/mem_encrypt.h>
  13
  14/**
  15 * List of possible attributes associated with a DMA mapping. The semantics
  16 * of each attribute should be defined in Documentation/core-api/dma-attributes.rst.
  17 */
  18
  19/*
  20 * DMA_ATTR_WEAK_ORDERING: Specifies that reads and writes to the mapping
  21 * may be weakly ordered, that is that reads and writes may pass each other.
  22 */
  23#define DMA_ATTR_WEAK_ORDERING          (1UL << 1)
  24/*
  25 * DMA_ATTR_WRITE_COMBINE: Specifies that writes to the mapping may be
  26 * buffered to improve performance.
  27 */
  28#define DMA_ATTR_WRITE_COMBINE          (1UL << 2)
  29/*
  30 * DMA_ATTR_NO_KERNEL_MAPPING: Lets the platform to avoid creating a kernel
  31 * virtual mapping for the allocated buffer.
  32 */
  33#define DMA_ATTR_NO_KERNEL_MAPPING      (1UL << 4)
  34/*
  35 * DMA_ATTR_SKIP_CPU_SYNC: Allows platform code to skip synchronization of
  36 * the CPU cache for the given buffer assuming that it has been already
  37 * transferred to 'device' domain.
  38 */
  39#define DMA_ATTR_SKIP_CPU_SYNC          (1UL << 5)
  40/*
  41 * DMA_ATTR_FORCE_CONTIGUOUS: Forces contiguous allocation of the buffer
  42 * in physical memory.
  43 */
  44#define DMA_ATTR_FORCE_CONTIGUOUS       (1UL << 6)
  45/*
  46 * DMA_ATTR_ALLOC_SINGLE_PAGES: This is a hint to the DMA-mapping subsystem
  47 * that it's probably not worth the time to try to allocate memory to in a way
  48 * that gives better TLB efficiency.
  49 */
  50#define DMA_ATTR_ALLOC_SINGLE_PAGES     (1UL << 7)
  51/*
  52 * DMA_ATTR_NO_WARN: This tells the DMA-mapping subsystem to suppress
  53 * allocation failure reports (similarly to __GFP_NOWARN).
  54 */
  55#define DMA_ATTR_NO_WARN        (1UL << 8)
  56
  57/*
  58 * DMA_ATTR_PRIVILEGED: used to indicate that the buffer is fully
  59 * accessible at an elevated privilege level (and ideally inaccessible or
  60 * at least read-only at lesser-privileged levels).
  61 */
  62#define DMA_ATTR_PRIVILEGED             (1UL << 9)
  63
  64/*
  65 * A dma_addr_t can hold any valid DMA or bus address for the platform.  It can
  66 * be given to a device to use as a DMA source or target.  It is specific to a
  67 * given device and there may be a translation between the CPU physical address
  68 * space and the bus address space.
  69 *
  70 * DMA_MAPPING_ERROR is the magic error code if a mapping failed.  It should not
  71 * be used directly in drivers, but checked for using dma_mapping_error()
  72 * instead.
  73 */
  74#define DMA_MAPPING_ERROR               (~(dma_addr_t)0)
  75
  76#define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
  77
  78#ifdef CONFIG_DMA_API_DEBUG
  79void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr);
  80void debug_dma_map_single(struct device *dev, const void *addr,
  81                unsigned long len);
  82#else
  83static inline void debug_dma_mapping_error(struct device *dev,
  84                dma_addr_t dma_addr)
  85{
  86}
  87static inline void debug_dma_map_single(struct device *dev, const void *addr,
  88                unsigned long len)
  89{
  90}
  91#endif /* CONFIG_DMA_API_DEBUG */
  92
  93#ifdef CONFIG_HAS_DMA
  94static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
  95{
  96        debug_dma_mapping_error(dev, dma_addr);
  97
  98        if (dma_addr == DMA_MAPPING_ERROR)
  99                return -ENOMEM;
 100        return 0;
 101}
 102
 103dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page,
 104                size_t offset, size_t size, enum dma_data_direction dir,
 105                unsigned long attrs);
 106void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size,
 107                enum dma_data_direction dir, unsigned long attrs);
 108int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents,
 109                enum dma_data_direction dir, unsigned long attrs);
 110void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
 111                                      int nents, enum dma_data_direction dir,
 112                                      unsigned long attrs);
 113dma_addr_t dma_map_resource(struct device *dev, phys_addr_t phys_addr,
 114                size_t size, enum dma_data_direction dir, unsigned long attrs);
 115void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
 116                enum dma_data_direction dir, unsigned long attrs);
 117void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
 118                enum dma_data_direction dir);
 119void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
 120                size_t size, enum dma_data_direction dir);
 121void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 122                    int nelems, enum dma_data_direction dir);
 123void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 124                       int nelems, enum dma_data_direction dir);
 125void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 126                gfp_t flag, unsigned long attrs);
 127void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
 128                dma_addr_t dma_handle, unsigned long attrs);
 129void *dmam_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 130                gfp_t gfp, unsigned long attrs);
 131void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
 132                dma_addr_t dma_handle);
 133int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt,
 134                void *cpu_addr, dma_addr_t dma_addr, size_t size,
 135                unsigned long attrs);
 136int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 137                void *cpu_addr, dma_addr_t dma_addr, size_t size,
 138                unsigned long attrs);
 139bool dma_can_mmap(struct device *dev);
 140int dma_supported(struct device *dev, u64 mask);
 141int dma_set_mask(struct device *dev, u64 mask);
 142int dma_set_coherent_mask(struct device *dev, u64 mask);
 143u64 dma_get_required_mask(struct device *dev);
 144size_t dma_max_mapping_size(struct device *dev);
 145bool dma_need_sync(struct device *dev, dma_addr_t dma_addr);
 146unsigned long dma_get_merge_boundary(struct device *dev);
 147#else /* CONFIG_HAS_DMA */
 148static inline dma_addr_t dma_map_page_attrs(struct device *dev,
 149                struct page *page, size_t offset, size_t size,
 150                enum dma_data_direction dir, unsigned long attrs)
 151{
 152        return DMA_MAPPING_ERROR;
 153}
 154static inline void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr,
 155                size_t size, enum dma_data_direction dir, unsigned long attrs)
 156{
 157}
 158static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
 159                int nents, enum dma_data_direction dir, unsigned long attrs)
 160{
 161        return 0;
 162}
 163static inline void dma_unmap_sg_attrs(struct device *dev,
 164                struct scatterlist *sg, int nents, enum dma_data_direction dir,
 165                unsigned long attrs)
 166{
 167}
 168static inline dma_addr_t dma_map_resource(struct device *dev,
 169                phys_addr_t phys_addr, size_t size, enum dma_data_direction dir,
 170                unsigned long attrs)
 171{
 172        return DMA_MAPPING_ERROR;
 173}
 174static inline void dma_unmap_resource(struct device *dev, dma_addr_t addr,
 175                size_t size, enum dma_data_direction dir, unsigned long attrs)
 176{
 177}
 178static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
 179                size_t size, enum dma_data_direction dir)
 180{
 181}
 182static inline void dma_sync_single_for_device(struct device *dev,
 183                dma_addr_t addr, size_t size, enum dma_data_direction dir)
 184{
 185}
 186static inline void dma_sync_sg_for_cpu(struct device *dev,
 187                struct scatterlist *sg, int nelems, enum dma_data_direction dir)
 188{
 189}
 190static inline void dma_sync_sg_for_device(struct device *dev,
 191                struct scatterlist *sg, int nelems, enum dma_data_direction dir)
 192{
 193}
 194static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 195{
 196        return -ENOMEM;
 197}
 198static inline void *dma_alloc_attrs(struct device *dev, size_t size,
 199                dma_addr_t *dma_handle, gfp_t flag, unsigned long attrs)
 200{
 201        return NULL;
 202}
 203static void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
 204                dma_addr_t dma_handle, unsigned long attrs)
 205{
 206}
 207static inline void *dmam_alloc_attrs(struct device *dev, size_t size,
 208                dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 209{
 210        return NULL;
 211}
 212static inline void dmam_free_coherent(struct device *dev, size_t size,
 213                void *vaddr, dma_addr_t dma_handle)
 214{
 215}
 216static inline int dma_get_sgtable_attrs(struct device *dev,
 217                struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr,
 218                size_t size, unsigned long attrs)
 219{
 220        return -ENXIO;
 221}
 222static inline int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 223                void *cpu_addr, dma_addr_t dma_addr, size_t size,
 224                unsigned long attrs)
 225{
 226        return -ENXIO;
 227}
 228static inline bool dma_can_mmap(struct device *dev)
 229{
 230        return false;
 231}
 232static inline int dma_supported(struct device *dev, u64 mask)
 233{
 234        return 0;
 235}
 236static inline int dma_set_mask(struct device *dev, u64 mask)
 237{
 238        return -EIO;
 239}
 240static inline int dma_set_coherent_mask(struct device *dev, u64 mask)
 241{
 242        return -EIO;
 243}
 244static inline u64 dma_get_required_mask(struct device *dev)
 245{
 246        return 0;
 247}
 248static inline size_t dma_max_mapping_size(struct device *dev)
 249{
 250        return 0;
 251}
 252static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
 253{
 254        return false;
 255}
 256static inline unsigned long dma_get_merge_boundary(struct device *dev)
 257{
 258        return 0;
 259}
 260#endif /* CONFIG_HAS_DMA */
 261
 262struct page *dma_alloc_pages(struct device *dev, size_t size,
 263                dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
 264void dma_free_pages(struct device *dev, size_t size, struct page *page,
 265                dma_addr_t dma_handle, enum dma_data_direction dir);
 266void *dma_alloc_noncoherent(struct device *dev, size_t size,
 267                dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
 268void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
 269                dma_addr_t dma_handle, enum dma_data_direction dir);
 270
 271static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
 272                size_t size, enum dma_data_direction dir, unsigned long attrs)
 273{
 274        /* DMA must never operate on areas that might be remapped. */
 275        if (dev_WARN_ONCE(dev, is_vmalloc_addr(ptr),
 276                          "rejecting DMA map of vmalloc memory\n"))
 277                return DMA_MAPPING_ERROR;
 278        debug_dma_map_single(dev, ptr, size);
 279        return dma_map_page_attrs(dev, virt_to_page(ptr), offset_in_page(ptr),
 280                        size, dir, attrs);
 281}
 282
 283static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
 284                size_t size, enum dma_data_direction dir, unsigned long attrs)
 285{
 286        return dma_unmap_page_attrs(dev, addr, size, dir, attrs);
 287}
 288
 289static inline void dma_sync_single_range_for_cpu(struct device *dev,
 290                dma_addr_t addr, unsigned long offset, size_t size,
 291                enum dma_data_direction dir)
 292{
 293        return dma_sync_single_for_cpu(dev, addr + offset, size, dir);
 294}
 295
 296static inline void dma_sync_single_range_for_device(struct device *dev,
 297                dma_addr_t addr, unsigned long offset, size_t size,
 298                enum dma_data_direction dir)
 299{
 300        return dma_sync_single_for_device(dev, addr + offset, size, dir);
 301}
 302
 303/**
 304 * dma_map_sgtable - Map the given buffer for DMA
 305 * @dev:        The device for which to perform the DMA operation
 306 * @sgt:        The sg_table object describing the buffer
 307 * @dir:        DMA direction
 308 * @attrs:      Optional DMA attributes for the map operation
 309 *
 310 * Maps a buffer described by a scatterlist stored in the given sg_table
 311 * object for the @dir DMA operation by the @dev device. After success the
 312 * ownership for the buffer is transferred to the DMA domain.  One has to
 313 * call dma_sync_sgtable_for_cpu() or dma_unmap_sgtable() to move the
 314 * ownership of the buffer back to the CPU domain before touching the
 315 * buffer by the CPU.
 316 *
 317 * Returns 0 on success or -EINVAL on error during mapping the buffer.
 318 */
 319static inline int dma_map_sgtable(struct device *dev, struct sg_table *sgt,
 320                enum dma_data_direction dir, unsigned long attrs)
 321{
 322        int nents;
 323
 324        nents = dma_map_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs);
 325        if (nents <= 0)
 326                return -EINVAL;
 327        sgt->nents = nents;
 328        return 0;
 329}
 330
 331/**
 332 * dma_unmap_sgtable - Unmap the given buffer for DMA
 333 * @dev:        The device for which to perform the DMA operation
 334 * @sgt:        The sg_table object describing the buffer
 335 * @dir:        DMA direction
 336 * @attrs:      Optional DMA attributes for the unmap operation
 337 *
 338 * Unmaps a buffer described by a scatterlist stored in the given sg_table
 339 * object for the @dir DMA operation by the @dev device. After this function
 340 * the ownership of the buffer is transferred back to the CPU domain.
 341 */
 342static inline void dma_unmap_sgtable(struct device *dev, struct sg_table *sgt,
 343                enum dma_data_direction dir, unsigned long attrs)
 344{
 345        dma_unmap_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs);
 346}
 347
 348/**
 349 * dma_sync_sgtable_for_cpu - Synchronize the given buffer for CPU access
 350 * @dev:        The device for which to perform the DMA operation
 351 * @sgt:        The sg_table object describing the buffer
 352 * @dir:        DMA direction
 353 *
 354 * Performs the needed cache synchronization and moves the ownership of the
 355 * buffer back to the CPU domain, so it is safe to perform any access to it
 356 * by the CPU. Before doing any further DMA operations, one has to transfer
 357 * the ownership of the buffer back to the DMA domain by calling the
 358 * dma_sync_sgtable_for_device().
 359 */
 360static inline void dma_sync_sgtable_for_cpu(struct device *dev,
 361                struct sg_table *sgt, enum dma_data_direction dir)
 362{
 363        dma_sync_sg_for_cpu(dev, sgt->sgl, sgt->orig_nents, dir);
 364}
 365
 366/**
 367 * dma_sync_sgtable_for_device - Synchronize the given buffer for DMA
 368 * @dev:        The device for which to perform the DMA operation
 369 * @sgt:        The sg_table object describing the buffer
 370 * @dir:        DMA direction
 371 *
 372 * Performs the needed cache synchronization and moves the ownership of the
 373 * buffer back to the DMA domain, so it is safe to perform the DMA operation.
 374 * Once finished, one has to call dma_sync_sgtable_for_cpu() or
 375 * dma_unmap_sgtable().
 376 */
 377static inline void dma_sync_sgtable_for_device(struct device *dev,
 378                struct sg_table *sgt, enum dma_data_direction dir)
 379{
 380        dma_sync_sg_for_device(dev, sgt->sgl, sgt->orig_nents, dir);
 381}
 382
 383#define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, 0)
 384#define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, 0)
 385#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, 0)
 386#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, 0)
 387#define dma_map_page(d, p, o, s, r) dma_map_page_attrs(d, p, o, s, r, 0)
 388#define dma_unmap_page(d, a, s, r) dma_unmap_page_attrs(d, a, s, r, 0)
 389#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, 0)
 390#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, 0)
 391
 392static inline void *dma_alloc_coherent(struct device *dev, size_t size,
 393                dma_addr_t *dma_handle, gfp_t gfp)
 394{
 395
 396        return dma_alloc_attrs(dev, size, dma_handle, gfp,
 397                        (gfp & __GFP_NOWARN) ? DMA_ATTR_NO_WARN : 0);
 398}
 399
 400static inline void dma_free_coherent(struct device *dev, size_t size,
 401                void *cpu_addr, dma_addr_t dma_handle)
 402{
 403        return dma_free_attrs(dev, size, cpu_addr, dma_handle, 0);
 404}
 405
 406
 407static inline u64 dma_get_mask(struct device *dev)
 408{
 409        if (dev->dma_mask && *dev->dma_mask)
 410                return *dev->dma_mask;
 411        return DMA_BIT_MASK(32);
 412}
 413
 414/*
 415 * Set both the DMA mask and the coherent DMA mask to the same thing.
 416 * Note that we don't check the return value from dma_set_coherent_mask()
 417 * as the DMA API guarantees that the coherent DMA mask can be set to
 418 * the same or smaller than the streaming DMA mask.
 419 */
 420static inline int dma_set_mask_and_coherent(struct device *dev, u64 mask)
 421{
 422        int rc = dma_set_mask(dev, mask);
 423        if (rc == 0)
 424                dma_set_coherent_mask(dev, mask);
 425        return rc;
 426}
 427
 428/*
 429 * Similar to the above, except it deals with the case where the device
 430 * does not have dev->dma_mask appropriately setup.
 431 */
 432static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
 433{
 434        dev->dma_mask = &dev->coherent_dma_mask;
 435        return dma_set_mask_and_coherent(dev, mask);
 436}
 437
 438/**
 439 * dma_addressing_limited - return if the device is addressing limited
 440 * @dev:        device to check
 441 *
 442 * Return %true if the devices DMA mask is too small to address all memory in
 443 * the system, else %false.  Lack of addressing bits is the prime reason for
 444 * bounce buffering, but might not be the only one.
 445 */
 446static inline bool dma_addressing_limited(struct device *dev)
 447{
 448        return min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
 449                            dma_get_required_mask(dev);
 450}
 451
 452static inline unsigned int dma_get_max_seg_size(struct device *dev)
 453{
 454        if (dev->dma_parms && dev->dma_parms->max_segment_size)
 455                return dev->dma_parms->max_segment_size;
 456        return SZ_64K;
 457}
 458
 459static inline int dma_set_max_seg_size(struct device *dev, unsigned int size)
 460{
 461        if (dev->dma_parms) {
 462                dev->dma_parms->max_segment_size = size;
 463                return 0;
 464        }
 465        return -EIO;
 466}
 467
 468static inline unsigned long dma_get_seg_boundary(struct device *dev)
 469{
 470        if (dev->dma_parms && dev->dma_parms->segment_boundary_mask)
 471                return dev->dma_parms->segment_boundary_mask;
 472        return ULONG_MAX;
 473}
 474
 475/**
 476 * dma_get_seg_boundary_nr_pages - return the segment boundary in "page" units
 477 * @dev: device to guery the boundary for
 478 * @page_shift: ilog() of the IOMMU page size
 479 *
 480 * Return the segment boundary in IOMMU page units (which may be different from
 481 * the CPU page size) for the passed in device.
 482 *
 483 * If @dev is NULL a boundary of U32_MAX is assumed, this case is just for
 484 * non-DMA API callers.
 485 */
 486static inline unsigned long dma_get_seg_boundary_nr_pages(struct device *dev,
 487                unsigned int page_shift)
 488{
 489        if (!dev)
 490                return (U32_MAX >> page_shift) + 1;
 491        return (dma_get_seg_boundary(dev) >> page_shift) + 1;
 492}
 493
 494static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask)
 495{
 496        if (dev->dma_parms) {
 497                dev->dma_parms->segment_boundary_mask = mask;
 498                return 0;
 499        }
 500        return -EIO;
 501}
 502
 503static inline int dma_get_cache_alignment(void)
 504{
 505#ifdef ARCH_DMA_MINALIGN
 506        return ARCH_DMA_MINALIGN;
 507#endif
 508        return 1;
 509}
 510
 511static inline void *dmam_alloc_coherent(struct device *dev, size_t size,
 512                dma_addr_t *dma_handle, gfp_t gfp)
 513{
 514        return dmam_alloc_attrs(dev, size, dma_handle, gfp,
 515                        (gfp & __GFP_NOWARN) ? DMA_ATTR_NO_WARN : 0);
 516}
 517
 518static inline void *dma_alloc_wc(struct device *dev, size_t size,
 519                                 dma_addr_t *dma_addr, gfp_t gfp)
 520{
 521        unsigned long attrs = DMA_ATTR_WRITE_COMBINE;
 522
 523        if (gfp & __GFP_NOWARN)
 524                attrs |= DMA_ATTR_NO_WARN;
 525
 526        return dma_alloc_attrs(dev, size, dma_addr, gfp, attrs);
 527}
 528
 529static inline void dma_free_wc(struct device *dev, size_t size,
 530                               void *cpu_addr, dma_addr_t dma_addr)
 531{
 532        return dma_free_attrs(dev, size, cpu_addr, dma_addr,
 533                              DMA_ATTR_WRITE_COMBINE);
 534}
 535
 536static inline int dma_mmap_wc(struct device *dev,
 537                              struct vm_area_struct *vma,
 538                              void *cpu_addr, dma_addr_t dma_addr,
 539                              size_t size)
 540{
 541        return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size,
 542                              DMA_ATTR_WRITE_COMBINE);
 543}
 544
 545#ifdef CONFIG_NEED_DMA_MAP_STATE
 546#define DEFINE_DMA_UNMAP_ADDR(ADDR_NAME)        dma_addr_t ADDR_NAME
 547#define DEFINE_DMA_UNMAP_LEN(LEN_NAME)          __u32 LEN_NAME
 548#define dma_unmap_addr(PTR, ADDR_NAME)           ((PTR)->ADDR_NAME)
 549#define dma_unmap_addr_set(PTR, ADDR_NAME, VAL)  (((PTR)->ADDR_NAME) = (VAL))
 550#define dma_unmap_len(PTR, LEN_NAME)             ((PTR)->LEN_NAME)
 551#define dma_unmap_len_set(PTR, LEN_NAME, VAL)    (((PTR)->LEN_NAME) = (VAL))
 552#else
 553#define DEFINE_DMA_UNMAP_ADDR(ADDR_NAME)
 554#define DEFINE_DMA_UNMAP_LEN(LEN_NAME)
 555#define dma_unmap_addr(PTR, ADDR_NAME)           (0)
 556#define dma_unmap_addr_set(PTR, ADDR_NAME, VAL)  do { } while (0)
 557#define dma_unmap_len(PTR, LEN_NAME)             (0)
 558#define dma_unmap_len_set(PTR, LEN_NAME, VAL)    do { } while (0)
 559#endif
 560
 561#endif /* _LINUX_DMA_MAPPING_H */
 562