drivers/gpu/drm/drm_gem_cma_helper.c

   1 /*
   2  * drm gem CMA (contiguous memory allocator) helper functions
   3  *
   4  * Copyright (C) 2012 Sascha Hauer, Pengutronix
   5  *
   6  * Based on Samsung Exynos code
   7  *
   8  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #include <linux/mm.h>
  21 #include <linux/slab.h>
  22 #include <linux/mutex.h>
  23 #include <linux/export.h>
  24 #include <linux/dma-buf.h>
  25 #include <linux/dma-mapping.h>
  26
  27 #include <drm/drmP.h>
  28 #include <drm/drm.h>
  29 #include <drm/drm_gem_cma_helper.h>
  30 #include <drm/drm_vma_manager.h>
  31
  32 /**
  33  * DOC: cma helpers
  34  *
  35  * The Contiguous Memory Allocator reserves a pool of memory at early boot
  36  * that is used to service requests for large blocks of contiguous memory.
  37  *
  38  * The DRM GEM/CMA helpers use this allocator as a means to provide buffer
  39  * objects that are physically contiguous in memory. This is useful for
  40  * display drivers that are unable to map scattered buffers via an IOMMU.
  41  */
  42
  43 /**
  44  * __drm_gem_cma_create - Create a GEM CMA object without allocating memory
  45  * @drm: DRM device
  46  * @size: size of the object to allocate
  47  *
  48  * This function creates and initializes a GEM CMA object of the given size,
  49  * but doesn't allocate any memory to back the object.
  50  *
  51  * Returns:
  52  * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
  53  * error code on failure.
  54  */
  55 static struct drm_gem_cma_object *
  56 __drm_gem_cma_create(struct drm_device *drm, size_t size)
  57 {
  58         struct drm_gem_cma_object *cma_obj;
  59         struct drm_gem_object *gem_obj;
  60         int ret;
  61
  62         if (drm->driver->gem_create_object)
  63                 gem_obj = drm->driver->gem_create_object(drm, size);
  64         else
  65                 gem_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
  66         if (!gem_obj)
  67                 return ERR_PTR(-ENOMEM);
  68         cma_obj = container_of(gem_obj, struct drm_gem_cma_object, base);
  69
  70         ret = drm_gem_object_init(drm, gem_obj, size);
  71         if (ret)
  72                 goto error;
  73
  74         ret = drm_gem_create_mmap_offset(gem_obj);
  75         if (ret) {
  76                 drm_gem_object_release(gem_obj);
  77                 goto error;
  78         }
  79
  80         return cma_obj;
  81
  82 error:
  83         kfree(cma_obj);
  84         return ERR_PTR(ret);
  85 }
  86
  87 /**
  88  * drm_gem_cma_create - allocate an object with the given size
  89  * @drm: DRM device
  90  * @size: size of the object to allocate
  91  *
  92  * This function creates a CMA GEM object and allocates a contiguous chunk of
  93  * memory as backing store. The backing memory has the writecombine attribute
  94  * set.
  95  *
  96  * Returns:
  97  * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
  98  * error code on failure.
  99  */
 100 struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
 101                                               size_t size)
 102 {
 103         struct drm_gem_cma_object *cma_obj;
 104         int ret;
 105
 106         size = round_up(size, PAGE_SIZE);
 107
 108         cma_obj = __drm_gem_cma_create(drm, size);
 109         if (IS_ERR(cma_obj))
 110                 return cma_obj;
 111
 112         cma_obj->vaddr = dma_alloc_wc(drm->dev, size, &cma_obj->paddr,
 113                                       GFP_KERNEL | __GFP_NOWARN);
 114         if (!cma_obj->vaddr) {
 115                 dev_dbg(drm->dev, "failed to allocate buffer with size %zu\n",
 116                         size);
 117                 ret = -ENOMEM;
 118                 goto error;
 119         }
 120
 121         return cma_obj;
 122
 123 error:
 124         drm_gem_object_put_unlocked(&cma_obj->base);
 125         return ERR_PTR(ret);
 126 }
 127 EXPORT_SYMBOL_GPL(drm_gem_cma_create);
 128
 129 /**
 130  * drm_gem_cma_create_with_handle - allocate an object with the given size and
 131  *     return a GEM handle to it
 132  * @file_priv: DRM file-private structure to register the handle for
 133  * @drm: DRM device
 134  * @size: size of the object to allocate
 135  * @handle: return location for the GEM handle
 136  *
 137  * This function creates a CMA GEM object, allocating a physically contiguous
 138  * chunk of memory as backing store. The GEM object is then added to the list
 139  * of object associated with the given file and a handle to it is returned.
 140  *
 141  * Returns:
 142  * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
 143  * error code on failure.
 144  */
 145 static struct drm_gem_cma_object *
 146 drm_gem_cma_create_with_handle(struct drm_file *file_priv,
 147                                struct drm_device *drm, size_t size,
 148                                uint32_t *handle)
 149 {
 150         struct drm_gem_cma_object *cma_obj;
 151         struct drm_gem_object *gem_obj;
 152         int ret;
 153
 154         cma_obj = drm_gem_cma_create(drm, size);
 155         if (IS_ERR(cma_obj))
 156                 return cma_obj;
 157
 158         gem_obj = &cma_obj->base;
 159
 160         /*
 161          * allocate a id of idr table where the obj is registered
 162          * and handle has the id what user can see.
 163          */
 164         ret = drm_gem_handle_create(file_priv, gem_obj, handle);
 165         /* drop reference from allocate - handle holds it now. */
 166         drm_gem_object_put_unlocked(gem_obj);
 167         if (ret)
 168                 return ERR_PTR(ret);
 169
 170         return cma_obj;
 171 }
 172
 173 /**
 174  * drm_gem_cma_free_object - free resources associated with a CMA GEM object
 175  * @gem_obj: GEM object to free
 176  *
 177  * This function frees the backing memory of the CMA GEM object, cleans up the
 178  * GEM object state and frees the memory used to store the object itself.
 179  * Drivers using the CMA helpers should set this as their
 180  * &drm_driver.gem_free_object_unlocked callback.
 181  */
 182 void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
 183 {
 184         struct drm_gem_cma_object *cma_obj;
 185
 186         cma_obj = to_drm_gem_cma_obj(gem_obj);
 187
 188         if (cma_obj->vaddr) {
 189                 dma_free_wc(gem_obj->dev->dev, cma_obj->base.size,
 190                             cma_obj->vaddr, cma_obj->paddr);
 191         } else if (gem_obj->import_attach) {
 192                 drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
 193         }
 194
 195         drm_gem_object_release(gem_obj);
 196
 197         kfree(cma_obj);
 198 }
 199 EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
 200
 201 /**
 202  * drm_gem_cma_dumb_create_internal - create a dumb buffer object
 203  * @file_priv: DRM file-private structure to create the dumb buffer for
 204  * @drm: DRM device
 205  * @args: IOCTL data
 206  *
 207  * This aligns the pitch and size arguments to the minimum required. This is
 208  * an internal helper that can be wrapped by a driver to account for hardware
 209  * with more specific alignment requirements. It should not be used directly
 210  * as their &drm_driver.dumb_create callback.
 211  *
 212  * Returns:
 213  * 0 on success or a negative error code on failure.
 214  */
 215 int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv,
 216                                      struct drm_device *drm,
 217                                      struct drm_mode_create_dumb *args)
 218 {
 219         unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 220         struct drm_gem_cma_object *cma_obj;
 221
 222         if (args->pitch < min_pitch)
 223                 args->pitch = min_pitch;
 224
 225         if (args->size < args->pitch * args->height)
 226                 args->size = args->pitch * args->height;
 227
 228         cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
 229                                                  &args->handle);
 230         return PTR_ERR_OR_ZERO(cma_obj);
 231 }
 232 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create_internal);
 233
 234 /**
 235  * drm_gem_cma_dumb_create - create a dumb buffer object
 236  * @file_priv: DRM file-private structure to create the dumb buffer for
 237  * @drm: DRM device
 238  * @args: IOCTL data
 239  *
 240  * This function computes the pitch of the dumb buffer and rounds it up to an
 241  * integer number of bytes per pixel. Drivers for hardware that doesn't have
 242  * any additional restrictions on the pitch can directly use this function as
 243  * their &drm_driver.dumb_create callback.
 244  *
 245  * For hardware with additional restrictions, drivers can adjust the fields
 246  * set up by userspace and pass the IOCTL data along to the
 247  * drm_gem_cma_dumb_create_internal() function.
 248  *
 249  * Returns:
 250  * 0 on success or a negative error code on failure.
 251  */
 252 int drm_gem_cma_dumb_create(struct drm_file *file_priv,
 253                             struct drm_device *drm,
 254                             struct drm_mode_create_dumb *args)
 255 {
 256         struct drm_gem_cma_object *cma_obj;
 257
 258         args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 259         args->size = args->pitch * args->height;
 260
 261         cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
 262                                                  &args->handle);
 263         return PTR_ERR_OR_ZERO(cma_obj);
 264 }
 265 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
 266
 267 const struct vm_operations_struct drm_gem_cma_vm_ops = {
 268         .open = drm_gem_vm_open,
 269         .close = drm_gem_vm_close,
 270 };
 271 EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
 272
 273 static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
 274                                 struct vm_area_struct *vma)
 275 {
 276         int ret;
 277
 278         /*
 279          * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
 280          * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
 281          * the whole buffer.
 282          */
 283         vma->vm_flags &= ~VM_PFNMAP;
 284         vma->vm_pgoff = 0;
 285
 286         ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
 287                           cma_obj->paddr, vma->vm_end - vma->vm_start);
 288         if (ret)
 289                 drm_gem_vm_close(vma);
 290
 291         return ret;
 292 }
 293
 294 /**
 295  * drm_gem_cma_mmap - memory-map a CMA GEM object
 296  * @filp: file object
 297  * @vma: VMA for the area to be mapped
 298  *
 299  * This function implements an augmented version of the GEM DRM file mmap
 300  * operation for CMA objects: In addition to the usual GEM VMA setup it
 301  * immediately faults in the entire object instead of using on-demaind
 302  * faulting. Drivers which employ the CMA helpers should use this function
 303  * as their ->mmap() handler in the DRM device file's file_operations
 304  * structure.
 305  *
 306  * Instead of directly referencing this function, drivers should use the
 307  * DEFINE_DRM_GEM_CMA_FOPS().macro.
 308  *
 309  * Returns:
 310  * 0 on success or a negative error code on failure.
 311  */
 312 int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
 313 {
 314         struct drm_gem_cma_object *cma_obj;
 315         struct drm_gem_object *gem_obj;
 316         int ret;
 317
 318         ret = drm_gem_mmap(filp, vma);
 319         if (ret)
 320                 return ret;
 321
 322         gem_obj = vma->vm_private_data;
 323         cma_obj = to_drm_gem_cma_obj(gem_obj);
 324
 325         return drm_gem_cma_mmap_obj(cma_obj, vma);
 326 }
 327 EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
 328
 329 #ifndef CONFIG_MMU
 330 /**
 331  * drm_gem_cma_get_unmapped_area - propose address for mapping in noMMU cases
 332  * @filp: file object
 333  * @addr: memory address
 334  * @len: buffer size
 335  * @pgoff: page offset
 336  * @flags: memory flags
 337  *
 338  * This function is used in noMMU platforms to propose address mapping
 339  * for a given buffer.
 340  * It's intended to be used as a direct handler for the struct
 341  * &file_operations.get_unmapped_area operation.
 342  *
 343  * Returns:
 344  * mapping address on success or a negative error code on failure.
 345  */
 346 unsigned long drm_gem_cma_get_unmapped_area(struct file *filp,
 347                                             unsigned long addr,
 348                                             unsigned long len,
 349                                             unsigned long pgoff,
 350                                             unsigned long flags)
 351 {
 352         struct drm_gem_cma_object *cma_obj;
 353         struct drm_gem_object *obj = NULL;
 354         struct drm_file *priv = filp->private_data;
 355         struct drm_device *dev = priv->minor->dev;
 356         struct drm_vma_offset_node *node;
 357
 358         if (drm_dev_is_unplugged(dev))
 359                 return -ENODEV;
 360
 361         drm_vma_offset_lock_lookup(dev->vma_offset_manager);
 362         node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
 363                                                   pgoff,
 364                                                   len >> PAGE_SHIFT);
 365         if (likely(node)) {
 366                 obj = container_of(node, struct drm_gem_object, vma_node);
 367                 /*
 368                  * When the object is being freed, after it hits 0-refcnt it
 369                  * proceeds to tear down the object. In the process it will
 370                  * attempt to remove the VMA offset and so acquire this
 371                  * mgr->vm_lock.  Therefore if we find an object with a 0-refcnt
 372                  * that matches our range, we know it is in the process of being
 373                  * destroyed and will be freed as soon as we release the lock -
 374                  * so we have to check for the 0-refcnted object and treat it as
 375                  * invalid.
 376                  */
 377                 if (!kref_get_unless_zero(&obj->refcount))
 378                         obj = NULL;
 379         }
 380
 381         drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
 382
 383         if (!obj)
 384                 return -EINVAL;
 385
 386         if (!drm_vma_node_is_allowed(node, priv)) {
 387                 drm_gem_object_put_unlocked(obj);
 388                 return -EACCES;
 389         }
 390
 391         cma_obj = to_drm_gem_cma_obj(obj);
 392
 393         drm_gem_object_put_unlocked(obj);
 394
 395         return cma_obj->vaddr ? (unsigned long)cma_obj->vaddr : -EINVAL;
 396 }
 397 EXPORT_SYMBOL_GPL(drm_gem_cma_get_unmapped_area);
 398 #endif
 399
 400 /**
 401  * drm_gem_cma_print_info() - Print &drm_gem_cma_object info for debugfs
 402  * @p: DRM printer
 403  * @indent: Tab indentation level
 404  * @obj: GEM object
 405  *
 406  * This function can be used as the &drm_driver->gem_print_info callback.
 407  * It prints paddr and vaddr for use in e.g. debugfs output.
 408  */
 409 void drm_gem_cma_print_info(struct drm_printer *p, unsigned int indent,
 410                             const struct drm_gem_object *obj)
 411 {
 412         const struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
 413
 414         drm_printf_indent(p, indent, "paddr=%pad\n", &cma_obj->paddr);
 415         drm_printf_indent(p, indent, "vaddr=%p\n", cma_obj->vaddr);
 416 }
 417 EXPORT_SYMBOL(drm_gem_cma_print_info);
 418
 419 /**
 420  * drm_gem_cma_prime_get_sg_table - provide a scatter/gather table of pinned
 421  *     pages for a CMA GEM object
 422  * @obj: GEM object
 423  *
 424  * This function exports a scatter/gather table suitable for PRIME usage by
 425  * calling the standard DMA mapping API. Drivers using the CMA helpers should
 426  * set this as their &drm_driver.gem_prime_get_sg_table callback.
 427  *
 428  * Returns:
 429  * A pointer to the scatter/gather table of pinned pages or NULL on failure.
 430  */
 431 struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj)
 432 {
 433         struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
 434         struct sg_table *sgt;
 435         int ret;
 436
 437         sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 438         if (!sgt)
 439                 return NULL;
 440
 441         ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr,
 442                               cma_obj->paddr, obj->size);
 443         if (ret < 0)
 444                 goto out;
 445
 446         return sgt;
 447
 448 out:
 449         kfree(sgt);
 450         return NULL;
 451 }
 452 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table);
 453
 454 /**
 455  * drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another
 456  *     driver's scatter/gather table of pinned pages
 457  * @dev: device to import into
 458  * @attach: DMA-BUF attachment
 459  * @sgt: scatter/gather table of pinned pages
 460  *
 461  * This function imports a scatter/gather table exported via DMA-BUF by
 462  * another driver. Imported buffers must be physically contiguous in memory
 463  * (i.e. the scatter/gather table must contain a single entry). Drivers that
 464  * use the CMA helpers should set this as their
 465  * &drm_driver.gem_prime_import_sg_table callback.
 466  *
 467  * Returns:
 468  * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
 469  * error code on failure.
 470  */
 471 struct drm_gem_object *
 472 drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
 473                                   struct dma_buf_attachment *attach,
 474                                   struct sg_table *sgt)
 475 {
 476         struct drm_gem_cma_object *cma_obj;
 477
 478         if (sgt->nents != 1) {
 479                 /* check if the entries in the sg_table are contiguous */
 480                 dma_addr_t next_addr = sg_dma_address(sgt->sgl);
 481                 struct scatterlist *s;
 482                 unsigned int i;
 483
 484                 for_each_sg(sgt->sgl, s, sgt->nents, i) {
 485                         /*
 486                          * sg_dma_address(s) is only valid for entries
 487                          * that have sg_dma_len(s) != 0
 488                          */
 489                         if (!sg_dma_len(s))
 490                                 continue;
 491
 492                         if (sg_dma_address(s) != next_addr)
 493                                 return ERR_PTR(-EINVAL);
 494
 495                         next_addr = sg_dma_address(s) + sg_dma_len(s);
 496                 }
 497         }
 498
 499         /* Create a CMA GEM buffer. */
 500         cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size);
 501         if (IS_ERR(cma_obj))
 502                 return ERR_CAST(cma_obj);
 503
 504         cma_obj->paddr = sg_dma_address(sgt->sgl);
 505         cma_obj->sgt = sgt;
 506
 507         DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size);
 508
 509         return &cma_obj->base;
 510 }
 511 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
 512
 513 /**
 514  * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
 515  * @obj: GEM object
 516  * @vma: VMA for the area to be mapped
 517  *
 518  * This function maps a buffer imported via DRM PRIME into a userspace
 519  * process's address space. Drivers that use the CMA helpers should set this
 520  * as their &drm_driver.gem_prime_mmap callback.
 521  *
 522  * Returns:
 523  * 0 on success or a negative error code on failure.
 524  */
 525 int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
 526                            struct vm_area_struct *vma)
 527 {
 528         struct drm_gem_cma_object *cma_obj;
 529         int ret;
 530
 531         ret = drm_gem_mmap_obj(obj, obj->size, vma);
 532         if (ret < 0)
 533                 return ret;
 534
 535         cma_obj = to_drm_gem_cma_obj(obj);
 536         return drm_gem_cma_mmap_obj(cma_obj, vma);
 537 }
 538 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
 539
 540 /**
 541  * drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual
 542  *     address space
 543  * @obj: GEM object
 544  *
 545  * This function maps a buffer exported via DRM PRIME into the kernel's
 546  * virtual address space. Since the CMA buffers are already mapped into the
 547  * kernel virtual address space this simply returns the cached virtual
 548  * address. Drivers using the CMA helpers should set this as their DRM
 549  * driver's &drm_driver.gem_prime_vmap callback.
 550  *
 551  * Returns:
 552  * The kernel virtual address of the CMA GEM object's backing store.
 553  */
 554 void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
 555 {
 556         struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
 557
 558         return cma_obj->vaddr;
 559 }
 560 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
 561
 562 /**
 563  * drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual
 564  *     address space
 565  * @obj: GEM object
 566  * @vaddr: kernel virtual address where the CMA GEM object was mapped
 567  *
 568  * This function removes a buffer exported via DRM PRIME from the kernel's
 569  * virtual address space. This is a no-op because CMA buffers cannot be
 570  * unmapped from kernel space. Drivers using the CMA helpers should set this
 571  * as their &drm_driver.gem_prime_vunmap callback.
 572  */
 573 void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
 574 {
 575         /* Nothing to do */
 576 }
 577 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);