include/asm-arm/dma-mapping.h

   1 #ifndef ASMARM_DMA_MAPPING_H
   2 #define ASMARM_DMA_MAPPING_H
   3
   4 #ifdef __KERNEL__
   5
   6 #include <linux/config.h>
   7 #include <linux/mm.h> /* need struct page */
   8
   9 #include <asm/scatterlist.h>
  10
  11 /*
  12  * DMA-consistent mapping functions.  These allocate/free a region of
  13  * uncached, unwrite-buffered mapped memory space for use with DMA
  14  * devices.  This is the "generic" version.  The PCI specific version
  15  * is in pci.h
  16  */
  17 extern void consistent_sync(void *kaddr, size_t size, int rw);
  18
  19 /*
  20  * Return whether the given device DMA address mask can be supported
  21  * properly.  For example, if your device can only drive the low 24-bits
  22  * during bus mastering, then you would pass 0x00ffffff as the mask
  23  * to this function.
  24  */
  25 static inline int dma_supported(struct device *dev, u64 mask)
  26 {
  27         return dev->dma_mask && *dev->dma_mask != 0;
  28 }
  29
  30 static inline int dma_set_mask(struct device *dev, u64 dma_mask)
  31 {
  32         if (!dev->dma_mask || !dma_supported(dev, dma_mask))
  33                 return -EIO;
  34
  35         *dev->dma_mask = dma_mask;
  36
  37         return 0;
  38 }
  39
  40 static inline int dma_get_cache_alignment(void)
  41 {
  42         return 32;
  43 }
  44
  45 static inline int dma_is_consistent(dma_addr_t handle)
  46 {
  47         return 0;
  48 }
  49
  50 /*
  51  * DMA errors are defined by all-bits-set in the DMA address.
  52  */
  53 static inline int dma_mapping_error(dma_addr_t dma_addr)
  54 {
  55         return dma_addr == ~0;
  56 }
  57
  58 /**
  59  * dma_alloc_coherent - allocate consistent memory for DMA
  60  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  61  * @size: required memory size
  62  * @handle: bus-specific DMA address
  63  *
  64  * Allocate some uncached, unbuffered memory for a device for
  65  * performing DMA.  This function allocates pages, and will
  66  * return the CPU-viewed address, and sets @handle to be the
  67  * device-viewed address.
  68  */
  69 extern void *
  70 dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, int gfp);
  71
  72 /**
  73  * dma_free_coherent - free memory allocated by dma_alloc_coherent
  74  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  75  * @size: size of memory originally requested in dma_alloc_coherent
  76  * @cpu_addr: CPU-view address returned from dma_alloc_coherent
  77  * @handle: device-view address returned from dma_alloc_coherent
  78  *
  79  * Free (and unmap) a DMA buffer previously allocated by
  80  * dma_alloc_coherent().
  81  *
  82  * References to memory and mappings associated with cpu_addr/handle
  83  * during and after this call executing are illegal.
  84  */
  85 extern void
  86 dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
  87                   dma_addr_t handle);
  88
  89 /**
  90  * dma_alloc_writecombine - allocate writecombining memory for DMA
  91  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
  92  * @size: required memory size
  93  * @handle: bus-specific DMA address
  94  *
  95  * Allocate some uncached, buffered memory for a device for
  96  * performing DMA.  This function allocates pages, and will
  97  * return the CPU-viewed address, and sets @handle to be the
  98  * device-viewed address.
  99  */
 100 extern void *
 101 dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, int gfp);
 102
 103 #define dma_free_writecombine(dev,size,cpu_addr,handle) \
 104         dma_free_coherent(dev,size,cpu_addr,handle)
 105
 106
 107 /**
 108  * dma_map_single - map a single buffer for streaming DMA
 109  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 110  * @cpu_addr: CPU direct mapped address of buffer
 111  * @size: size of buffer to map
 112  * @dir: DMA transfer direction
 113  *
 114  * Ensure that any data held in the cache is appropriately discarded
 115  * or written back.
 116  *
 117  * The device owns this memory once this call has completed.  The CPU
 118  * can regain ownership by calling dma_unmap_single() or
 119  * dma_sync_single_for_cpu().
 120  */
 121 #ifndef CONFIG_DMABOUNCE
 122 static inline dma_addr_t
 123 dma_map_single(struct device *dev, void *cpu_addr, size_t size,
 124                enum dma_data_direction dir)
 125 {
 126         consistent_sync(cpu_addr, size, dir);
 127         return virt_to_dma(dev, (unsigned long)cpu_addr);
 128 }
 129 #else
 130 extern dma_addr_t dma_map_single(struct device *,void *, size_t, enum dma_data_direction);
 131 #endif
 132
 133 /**
 134  * dma_map_page - map a portion of a page for streaming DMA
 135  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 136  * @page: page that buffer resides in
 137  * @offset: offset into page for start of buffer
 138  * @size: size of buffer to map
 139  * @dir: DMA transfer direction
 140  *
 141  * Ensure that any data held in the cache is appropriately discarded
 142  * or written back.
 143  *
 144  * The device owns this memory once this call has completed.  The CPU
 145  * can regain ownership by calling dma_unmap_page() or
 146  * dma_sync_single_for_cpu().
 147  */
 148 static inline dma_addr_t
 149 dma_map_page(struct device *dev, struct page *page,
 150              unsigned long offset, size_t size,
 151              enum dma_data_direction dir)
 152 {
 153         return dma_map_single(dev, page_address(page) + offset, size, (int)dir);
 154 }
 155
 156 /**
 157  * dma_unmap_single - unmap a single buffer previously mapped
 158  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 159  * @handle: DMA address of buffer
 160  * @size: size of buffer to map
 161  * @dir: DMA transfer direction
 162  *
 163  * Unmap a single streaming mode DMA translation.  The handle and size
 164  * must match what was provided in the previous dma_map_single() call.
 165  * All other usages are undefined.
 166  *
 167  * After this call, reads by the CPU to the buffer are guaranteed to see
 168  * whatever the device wrote there.
 169  */
 170 #ifndef CONFIG_DMABOUNCE
 171 static inline void
 172 dma_unmap_single(struct device *dev, dma_addr_t handle, size_t size,
 173                  enum dma_data_direction dir)
 174 {
 175         /* nothing to do */
 176 }
 177 #else
 178 extern void dma_unmap_single(struct device *, dma_addr_t, size_t, enum dma_data_direction);
 179 #endif
 180
 181 /**
 182  * dma_unmap_page - unmap a buffer previously mapped through dma_map_page()
 183  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 184  * @handle: DMA address of buffer
 185  * @size: size of buffer to map
 186  * @dir: DMA transfer direction
 187  *
 188  * Unmap a single streaming mode DMA translation.  The handle and size
 189  * must match what was provided in the previous dma_map_single() call.
 190  * All other usages are undefined.
 191  *
 192  * After this call, reads by the CPU to the buffer are guaranteed to see
 193  * whatever the device wrote there.
 194  */
 195 static inline void
 196 dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
 197                enum dma_data_direction dir)
 198 {
 199         dma_unmap_single(dev, handle, size, (int)dir);
 200 }
 201
 202 /**
 203  * dma_map_sg - map a set of SG buffers for streaming mode DMA
 204  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 205  * @sg: list of buffers
 206  * @nents: number of buffers to map
 207  * @dir: DMA transfer direction
 208  *
 209  * Map a set of buffers described by scatterlist in streaming
 210  * mode for DMA.  This is the scatter-gather version of the
 211  * above dma_map_single interface.  Here the scatter gather list
 212  * elements are each tagged with the appropriate dma address
 213  * and length.  They are obtained via sg_dma_{address,length}(SG).
 214  *
 215  * NOTE: An implementation may be able to use a smaller number of
 216  *       DMA address/length pairs than there are SG table elements.
 217  *       (for example via virtual mapping capabilities)
 218  *       The routine returns the number of addr/length pairs actually
 219  *       used, at most nents.
 220  *
 221  * Device ownership issues as mentioned above for dma_map_single are
 222  * the same here.
 223  */
 224 #ifndef CONFIG_DMABOUNCE
 225 static inline int
 226 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 227            enum dma_data_direction dir)
 228 {
 229         int i;
 230
 231         for (i = 0; i < nents; i++, sg++) {
 232                 char *virt;
 233
 234                 sg->dma_address = page_to_dma(dev, sg->page) + sg->offset;
 235                 virt = page_address(sg->page) + sg->offset;
 236                 consistent_sync(virt, sg->length, dir);
 237         }
 238
 239         return nents;
 240 }
 241 #else
 242 extern int dma_map_sg(struct device *, struct scatterlist *, int, enum dma_data_direction);
 243 #endif
 244
 245 /**
 246  * dma_unmap_sg - unmap a set of SG buffers mapped by dma_map_sg
 247  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 248  * @sg: list of buffers
 249  * @nents: number of buffers to map
 250  * @dir: DMA transfer direction
 251  *
 252  * Unmap a set of streaming mode DMA translations.
 253  * Again, CPU read rules concerning calls here are the same as for
 254  * dma_unmap_single() above.
 255  */
 256 #ifndef CONFIG_DMABOUNCE
 257 static inline void
 258 dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
 259              enum dma_data_direction dir)
 260 {
 261
 262         /* nothing to do */
 263 }
 264 #else
 265 extern void dma_unmap_sg(struct device *, struct scatterlist *, int, enum dma_data_direction);
 266 #endif
 267
 268
 269 /**
 270  * dma_sync_single_for_cpu
 271  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 272  * @handle: DMA address of buffer
 273  * @size: size of buffer to map
 274  * @dir: DMA transfer direction
 275  *
 276  * Make physical memory consistent for a single streaming mode DMA
 277  * translation after a transfer.
 278  *
 279  * If you perform a dma_map_single() but wish to interrogate the
 280  * buffer using the cpu, yet do not wish to teardown the PCI dma
 281  * mapping, you must call this function before doing so.  At the
 282  * next point you give the PCI dma address back to the card, you
 283  * must first the perform a dma_sync_for_device, and then the
 284  * device again owns the buffer.
 285  */
 286 #ifndef CONFIG_DMABOUNCE
 287 static inline void
 288 dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle, size_t size,
 289                         enum dma_data_direction dir)
 290 {
 291         consistent_sync((void *)dma_to_virt(dev, handle), size, dir);
 292 }
 293
 294 static inline void
 295 dma_sync_single_for_device(struct device *dev, dma_addr_t handle, size_t size,
 296                            enum dma_data_direction dir)
 297 {
 298         consistent_sync((void *)dma_to_virt(dev, handle), size, dir);
 299 }
 300 #else
 301 extern void dma_sync_single_for_cpu(struct device*, dma_addr_t, size_t, enum dma_data_direction);
 302 extern void dma_sync_single_for_device(struct device*, dma_addr_t, size_t, enum dma_data_direction);
 303 #endif
 304
 305
 306 /**
 307  * dma_sync_sg_for_cpu
 308  * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
 309  * @sg: list of buffers
 310  * @nents: number of buffers to map
 311  * @dir: DMA transfer direction
 312  *
 313  * Make physical memory consistent for a set of streaming
 314  * mode DMA translations after a transfer.
 315  *
 316  * The same as dma_sync_single_for_* but for a scatter-gather list,
 317  * same rules and usage.
 318  */
 319 #ifndef CONFIG_DMABOUNCE
 320 static inline void
 321 dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,
 322                     enum dma_data_direction dir)
 323 {
 324         int i;
 325
 326         for (i = 0; i < nents; i++, sg++) {
 327                 char *virt = page_address(sg->page) + sg->offset;
 328                 consistent_sync(virt, sg->length, dir);
 329         }
 330 }
 331
 332 static inline void
 333 dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents,
 334                        enum dma_data_direction dir)
 335 {
 336         int i;
 337
 338         for (i = 0; i < nents; i++, sg++) {
 339                 char *virt = page_address(sg->page) + sg->offset;
 340                 consistent_sync(virt, sg->length, dir);
 341         }
 342 }
 343 #else
 344 extern void dma_sync_sg_for_cpu(struct device*, struct scatterlist*, int, enum dma_data_direction);
 345 extern void dma_sync_sg_for_device(struct device*, struct scatterlist*, int, enum dma_data_direction);
 346 #endif
 347
 348 #ifdef CONFIG_DMABOUNCE
 349 /*
 350  * For SA-1111, IXP425, and ADI systems  the dma-mapping functions are "magic"
 351  * and utilize bounce buffers as needed to work around limited DMA windows.
 352  *
 353  * On the SA-1111, a bug limits DMA to only certain regions of RAM.
 354  * On the IXP425, the PCI inbound window is 64MB (256MB total RAM)
 355  * On some ADI engineering sytems, PCI inbound window is 32MB (12MB total RAM)
 356  *
 357  * The following are helper functions used by the dmabounce subystem
 358  *
 359  */
 360
 361 /**
 362  * dmabounce_register_dev
 363  *
 364  * @dev: valid struct device pointer
 365  * @small_buf_size: size of buffers to use with small buffer pool
 366  * @large_buf_size: size of buffers to use with large buffer pool (can be 0)
 367  *
 368  * This function should be called by low-level platform code to register
 369  * a device as requireing DMA buffer bouncing. The function will allocate
 370  * appropriate DMA pools for the device.
 371  *
 372  */
 373 extern int dmabounce_register_dev(struct device *, unsigned long, unsigned long);
 374
 375 /**
 376  * dmabounce_unregister_dev
 377  *
 378  * @dev: valid struct device pointer
 379  *
 380  * This function should be called by low-level platform code when device
 381  * that was previously registered with dmabounce_register_dev is removed
 382  * from the system.
 383  *
 384  */
 385 extern void dmabounce_unregister_dev(struct device *);
 386
 387 /**
 388  * dma_needs_bounce
 389  *
 390  * @dev: valid struct device pointer
 391  * @dma_handle: dma_handle of unbounced buffer
 392  * @size: size of region being mapped
 393  *
 394  * Platforms that utilize the dmabounce mechanism must implement
 395  * this function.
 396  *
 397  * The dmabounce routines call this function whenever a dma-mapping
 398  * is requested to determine whether a given buffer needs to be bounced
 399  * or not. The function must return 0 if the the buffer is OK for
 400  * DMA access and 1 if the buffer needs to be bounced.
 401  *
 402  */
 403 extern int dma_needs_bounce(struct device*, dma_addr_t, size_t);
 404 #endif /* CONFIG_DMABOUNCE */
 405
 406 #endif /* __KERNEL__ */
 407 #endif