drivers/base/dma-buf.c

   1 /*
   2  * Framework for buffer objects that can be shared across devices/subsystems.
   3  *
   4  * Copyright(C) 2011 Linaro Limited. All rights reserved.
   5  * Author: Sumit Semwal <sumit.semwal@ti.com>
   6  *
   7  * Many thanks to linaro-mm-sig list, and specially
   8  * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
   9  * Daniel Vetter <daniel@ffwll.ch> for their support in creation and
  10  * refining of this idea.
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU General Public License version 2 as published by
  14  * the Free Software Foundation.
  15  *
  16  * This program is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  19  * more details.
  20  *
  21  * You should have received a copy of the GNU General Public License along with
  22  * this program.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24
  25 #include <linux/fs.h>
  26 #include <linux/slab.h>
  27 #include <linux/dma-buf.h>
  28 #include <linux/anon_inodes.h>
  29 #include <linux/export.h>
  30
  31 static inline int is_dma_buf_file(struct file *);
  32
  33 static int dma_buf_release(struct inode *inode, struct file *file)
  34 {
  35         struct dma_buf *dmabuf;
  36
  37         if (!is_dma_buf_file(file))
  38                 return -EINVAL;
  39
  40         dmabuf = file->private_data;
  41
  42         BUG_ON(dmabuf->vmapping_counter);
  43
  44         dmabuf->ops->release(dmabuf);
  45         kfree(dmabuf);
  46         return 0;
  47 }
  48
  49 static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
  50 {
  51         struct dma_buf *dmabuf;
  52
  53         if (!is_dma_buf_file(file))
  54                 return -EINVAL;
  55
  56         dmabuf = file->private_data;
  57
  58         /* check for overflowing the buffer's size */
  59         if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
  60             dmabuf->size >> PAGE_SHIFT)
  61                 return -EINVAL;
  62
  63         return dmabuf->ops->mmap(dmabuf, vma);
  64 }
  65
  66 static const struct file_operations dma_buf_fops = {
  67         .release        = dma_buf_release,
  68         .mmap           = dma_buf_mmap_internal,
  69 };
  70
  71 /*
  72  * is_dma_buf_file - Check if struct file* is associated with dma_buf
  73  */
  74 static inline int is_dma_buf_file(struct file *file)
  75 {
  76         return file->f_op == &dma_buf_fops;
  77 }
  78
  79 /**
  80  * dma_buf_export - Creates a new dma_buf, and associates an anon file
  81  * with this buffer, so it can be exported.
  82  * Also connect the allocator specific data and ops to the buffer.
  83  *
  84  * @priv:       [in]    Attach private data of allocator to this buffer
  85  * @ops:        [in]    Attach allocator-defined dma buf ops to the new buffer.
  86  * @size:       [in]    Size of the buffer
  87  * @flags:      [in]    mode flags for the file.
  88  *
  89  * Returns, on success, a newly created dma_buf object, which wraps the
  90  * supplied private data and operations for dma_buf_ops. On either missing
  91  * ops, or error in allocating struct dma_buf, will return negative error.
  92  *
  93  */
  94 struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
  95                                 size_t size, int flags)
  96 {
  97         struct dma_buf *dmabuf;
  98         struct file *file;
  99
 100         if (WARN_ON(!priv || !ops
 101                           || !ops->map_dma_buf
 102                           || !ops->unmap_dma_buf
 103                           || !ops->release
 104                           || !ops->kmap_atomic
 105                           || !ops->kmap
 106                           || !ops->mmap)) {
 107                 return ERR_PTR(-EINVAL);
 108         }
 109
 110         dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL);
 111         if (dmabuf == NULL)
 112                 return ERR_PTR(-ENOMEM);
 113
 114         dmabuf->priv = priv;
 115         dmabuf->ops = ops;
 116         dmabuf->size = size;
 117
 118         file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
 119
 120         dmabuf->file = file;
 121
 122         mutex_init(&dmabuf->lock);
 123         INIT_LIST_HEAD(&dmabuf->attachments);
 124
 125         return dmabuf;
 126 }
 127 EXPORT_SYMBOL_GPL(dma_buf_export);
 128
 129
 130 /**
 131  * dma_buf_fd - returns a file descriptor for the given dma_buf
 132  * @dmabuf:     [in]    pointer to dma_buf for which fd is required.
 133  * @flags:      [in]    flags to give to fd
 134  *
 135  * On success, returns an associated 'fd'. Else, returns error.
 136  */
 137 int dma_buf_fd(struct dma_buf *dmabuf, int flags)
 138 {
 139         int fd;
 140
 141         if (!dmabuf || !dmabuf->file)
 142                 return -EINVAL;
 143
 144         fd = get_unused_fd_flags(flags);
 145         if (fd < 0)
 146                 return fd;
 147
 148         fd_install(fd, dmabuf->file);
 149
 150         return fd;
 151 }
 152 EXPORT_SYMBOL_GPL(dma_buf_fd);
 153
 154 /**
 155  * dma_buf_get - returns the dma_buf structure related to an fd
 156  * @fd: [in]    fd associated with the dma_buf to be returned
 157  *
 158  * On success, returns the dma_buf structure associated with an fd; uses
 159  * file's refcounting done by fget to increase refcount. returns ERR_PTR
 160  * otherwise.
 161  */
 162 struct dma_buf *dma_buf_get(int fd)
 163 {
 164         struct file *file;
 165
 166         file = fget(fd);
 167
 168         if (!file)
 169                 return ERR_PTR(-EBADF);
 170
 171         if (!is_dma_buf_file(file)) {
 172                 fput(file);
 173                 return ERR_PTR(-EINVAL);
 174         }
 175
 176         return file->private_data;
 177 }
 178 EXPORT_SYMBOL_GPL(dma_buf_get);
 179
 180 /**
 181  * dma_buf_put - decreases refcount of the buffer
 182  * @dmabuf:     [in]    buffer to reduce refcount of
 183  *
 184  * Uses file's refcounting done implicitly by fput()
 185  */
 186 void dma_buf_put(struct dma_buf *dmabuf)
 187 {
 188         if (WARN_ON(!dmabuf || !dmabuf->file))
 189                 return;
 190
 191         fput(dmabuf->file);
 192 }
 193 EXPORT_SYMBOL_GPL(dma_buf_put);
 194
 195 /**
 196  * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
 197  * calls attach() of dma_buf_ops to allow device-specific attach functionality
 198  * @dmabuf:     [in]    buffer to attach device to.
 199  * @dev:        [in]    device to be attached.
 200  *
 201  * Returns struct dma_buf_attachment * for this attachment; may return negative
 202  * error codes.
 203  *
 204  */
 205 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
 206                                           struct device *dev)
 207 {
 208         struct dma_buf_attachment *attach;
 209         int ret;
 210
 211         if (WARN_ON(!dmabuf || !dev))
 212                 return ERR_PTR(-EINVAL);
 213
 214         attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
 215         if (attach == NULL)
 216                 return ERR_PTR(-ENOMEM);
 217
 218         attach->dev = dev;
 219         attach->dmabuf = dmabuf;
 220
 221         mutex_lock(&dmabuf->lock);
 222
 223         if (dmabuf->ops->attach) {
 224                 ret = dmabuf->ops->attach(dmabuf, dev, attach);
 225                 if (ret)
 226                         goto err_attach;
 227         }
 228         list_add(&attach->node, &dmabuf->attachments);
 229
 230         mutex_unlock(&dmabuf->lock);
 231         return attach;
 232
 233 err_attach:
 234         kfree(attach);
 235         mutex_unlock(&dmabuf->lock);
 236         return ERR_PTR(ret);
 237 }
 238 EXPORT_SYMBOL_GPL(dma_buf_attach);
 239
 240 /**
 241  * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
 242  * optionally calls detach() of dma_buf_ops for device-specific detach
 243  * @dmabuf:     [in]    buffer to detach from.
 244  * @attach:     [in]    attachment to be detached; is free'd after this call.
 245  *
 246  */
 247 void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
 248 {
 249         if (WARN_ON(!dmabuf || !attach))
 250                 return;
 251
 252         mutex_lock(&dmabuf->lock);
 253         list_del(&attach->node);
 254         if (dmabuf->ops->detach)
 255                 dmabuf->ops->detach(dmabuf, attach);
 256
 257         mutex_unlock(&dmabuf->lock);
 258         kfree(attach);
 259 }
 260 EXPORT_SYMBOL_GPL(dma_buf_detach);
 261
 262 /**
 263  * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
 264  * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
 265  * dma_buf_ops.
 266  * @attach:     [in]    attachment whose scatterlist is to be returned
 267  * @direction:  [in]    direction of DMA transfer
 268  *
 269  * Returns sg_table containing the scatterlist to be returned; may return NULL
 270  * or ERR_PTR.
 271  *
 272  */
 273 struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
 274                                         enum dma_data_direction direction)
 275 {
 276         struct sg_table *sg_table = ERR_PTR(-EINVAL);
 277
 278         might_sleep();
 279
 280         if (WARN_ON(!attach || !attach->dmabuf))
 281                 return ERR_PTR(-EINVAL);
 282
 283         sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
 284
 285         return sg_table;
 286 }
 287 EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
 288
 289 /**
 290  * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
 291  * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
 292  * dma_buf_ops.
 293  * @attach:     [in]    attachment to unmap buffer from
 294  * @sg_table:   [in]    scatterlist info of the buffer to unmap
 295  * @direction:  [in]    direction of DMA transfer
 296  *
 297  */
 298 void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
 299                                 struct sg_table *sg_table,
 300                                 enum dma_data_direction direction)
 301 {
 302         might_sleep();
 303
 304         if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
 305                 return;
 306
 307         attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
 308                                                 direction);
 309 }
 310 EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
 311
 312
 313 /**
 314  * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
 315  * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
 316  * preparations. Coherency is only guaranteed in the specified range for the
 317  * specified access direction.
 318  * @dmabuf:     [in]    buffer to prepare cpu access for.
 319  * @start:      [in]    start of range for cpu access.
 320  * @len:        [in]    length of range for cpu access.
 321  * @direction:  [in]    length of range for cpu access.
 322  *
 323  * Can return negative error values, returns 0 on success.
 324  */
 325 int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
 326                              enum dma_data_direction direction)
 327 {
 328         int ret = 0;
 329
 330         if (WARN_ON(!dmabuf))
 331                 return -EINVAL;
 332
 333         if (dmabuf->ops->begin_cpu_access)
 334                 ret = dmabuf->ops->begin_cpu_access(dmabuf, start, len, direction);
 335
 336         return ret;
 337 }
 338 EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
 339
 340 /**
 341  * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
 342  * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
 343  * actions. Coherency is only guaranteed in the specified range for the
 344  * specified access direction.
 345  * @dmabuf:     [in]    buffer to complete cpu access for.
 346  * @start:      [in]    start of range for cpu access.
 347  * @len:        [in]    length of range for cpu access.
 348  * @direction:  [in]    length of range for cpu access.
 349  *
 350  * This call must always succeed.
 351  */
 352 void dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
 353                             enum dma_data_direction direction)
 354 {
 355         WARN_ON(!dmabuf);
 356
 357         if (dmabuf->ops->end_cpu_access)
 358                 dmabuf->ops->end_cpu_access(dmabuf, start, len, direction);
 359 }
 360 EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
 361
 362 /**
 363  * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
 364  * space. The same restrictions as for kmap_atomic and friends apply.
 365  * @dmabuf:     [in]    buffer to map page from.
 366  * @page_num:   [in]    page in PAGE_SIZE units to map.
 367  *
 368  * This call must always succeed, any necessary preparations that might fail
 369  * need to be done in begin_cpu_access.
 370  */
 371 void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
 372 {
 373         WARN_ON(!dmabuf);
 374
 375         return dmabuf->ops->kmap_atomic(dmabuf, page_num);
 376 }
 377 EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
 378
 379 /**
 380  * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
 381  * @dmabuf:     [in]    buffer to unmap page from.
 382  * @page_num:   [in]    page in PAGE_SIZE units to unmap.
 383  * @vaddr:      [in]    kernel space pointer obtained from dma_buf_kmap_atomic.
 384  *
 385  * This call must always succeed.
 386  */
 387 void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
 388                            void *vaddr)
 389 {
 390         WARN_ON(!dmabuf);
 391
 392         if (dmabuf->ops->kunmap_atomic)
 393                 dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
 394 }
 395 EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
 396
 397 /**
 398  * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
 399  * same restrictions as for kmap and friends apply.
 400  * @dmabuf:     [in]    buffer to map page from.
 401  * @page_num:   [in]    page in PAGE_SIZE units to map.
 402  *
 403  * This call must always succeed, any necessary preparations that might fail
 404  * need to be done in begin_cpu_access.
 405  */
 406 void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
 407 {
 408         WARN_ON(!dmabuf);
 409
 410         return dmabuf->ops->kmap(dmabuf, page_num);
 411 }
 412 EXPORT_SYMBOL_GPL(dma_buf_kmap);
 413
 414 /**
 415  * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
 416  * @dmabuf:     [in]    buffer to unmap page from.
 417  * @page_num:   [in]    page in PAGE_SIZE units to unmap.
 418  * @vaddr:      [in]    kernel space pointer obtained from dma_buf_kmap.
 419  *
 420  * This call must always succeed.
 421  */
 422 void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
 423                     void *vaddr)
 424 {
 425         WARN_ON(!dmabuf);
 426
 427         if (dmabuf->ops->kunmap)
 428                 dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
 429 }
 430 EXPORT_SYMBOL_GPL(dma_buf_kunmap);
 431
 432
 433 /**
 434  * dma_buf_mmap - Setup up a userspace mmap with the given vma
 435  * @dmabuf:     [in]    buffer that should back the vma
 436  * @vma:        [in]    vma for the mmap
 437  * @pgoff:      [in]    offset in pages where this mmap should start within the
 438  *                      dma-buf buffer.
 439  *
 440  * This function adjusts the passed in vma so that it points at the file of the
 441  * dma_buf operation. It alsog adjusts the starting pgoff and does bounds
 442  * checking on the size of the vma. Then it calls the exporters mmap function to
 443  * set up the mapping.
 444  *
 445  * Can return negative error values, returns 0 on success.
 446  */
 447 int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
 448                  unsigned long pgoff)
 449 {
 450         struct file *oldfile;
 451         int ret;
 452
 453         if (WARN_ON(!dmabuf || !vma))
 454                 return -EINVAL;
 455
 456         /* check for offset overflow */
 457         if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
 458                 return -EOVERFLOW;
 459
 460         /* check for overflowing the buffer's size */
 461         if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
 462             dmabuf->size >> PAGE_SHIFT)
 463                 return -EINVAL;
 464
 465         /* readjust the vma */
 466         get_file(dmabuf->file);
 467         oldfile = vma->vm_file;
 468         vma->vm_file = dmabuf->file;
 469         vma->vm_pgoff = pgoff;
 470
 471         ret = dmabuf->ops->mmap(dmabuf, vma);
 472         if (ret) {
 473                 /* restore old parameters on failure */
 474                 vma->vm_file = oldfile;
 475                 fput(dmabuf->file);
 476         } else {
 477                 if (oldfile)
 478                         fput(oldfile);
 479         }
 480         return ret;
 481
 482 }
 483 EXPORT_SYMBOL_GPL(dma_buf_mmap);
 484
 485 /**
 486  * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
 487  * address space. Same restrictions as for vmap and friends apply.
 488  * @dmabuf:     [in]    buffer to vmap
 489  *
 490  * This call may fail due to lack of virtual mapping address space.
 491  * These calls are optional in drivers. The intended use for them
 492  * is for mapping objects linear in kernel space for high use objects.
 493  * Please attempt to use kmap/kunmap before thinking about these interfaces.
 494  */
 495 void *dma_buf_vmap(struct dma_buf *dmabuf)
 496 {
 497         void *ptr;
 498
 499         if (WARN_ON(!dmabuf))
 500                 return NULL;
 501
 502         if (!dmabuf->ops->vmap)
 503                 return NULL;
 504
 505         mutex_lock(&dmabuf->lock);
 506         if (dmabuf->vmapping_counter) {
 507                 dmabuf->vmapping_counter++;
 508                 BUG_ON(!dmabuf->vmap_ptr);
 509                 ptr = dmabuf->vmap_ptr;
 510                 goto out_unlock;
 511         }
 512
 513         BUG_ON(dmabuf->vmap_ptr);
 514
 515         ptr = dmabuf->ops->vmap(dmabuf);
 516         if (IS_ERR_OR_NULL(ptr))
 517                 goto out_unlock;
 518
 519         dmabuf->vmap_ptr = ptr;
 520         dmabuf->vmapping_counter = 1;
 521
 522 out_unlock:
 523         mutex_unlock(&dmabuf->lock);
 524         return ptr;
 525 }
 526 EXPORT_SYMBOL_GPL(dma_buf_vmap);
 527
 528 /**
 529  * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
 530  * @dmabuf:     [in]    buffer to vunmap
 531  * @vaddr:      [in]    vmap to vunmap
 532  */
 533 void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
 534 {
 535         if (WARN_ON(!dmabuf))
 536                 return;
 537
 538         BUG_ON(!dmabuf->vmap_ptr);
 539         BUG_ON(dmabuf->vmapping_counter == 0);
 540         BUG_ON(dmabuf->vmap_ptr != vaddr);
 541
 542         mutex_lock(&dmabuf->lock);
 543         if (--dmabuf->vmapping_counter == 0) {
 544                 if (dmabuf->ops->vunmap)
 545                         dmabuf->ops->vunmap(dmabuf, vaddr);
 546                 dmabuf->vmap_ptr = NULL;
 547         }
 548         mutex_unlock(&dmabuf->lock);
 549 }
 550 EXPORT_SYMBOL_GPL(dma_buf_vunmap);