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         cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
  63         if (!cma_obj)
  64                 return ERR_PTR(-ENOMEM);
  65
  66         gem_obj = &cma_obj->base;
  67
  68         ret = drm_gem_object_init(drm, gem_obj, size);
  69         if (ret)
  70                 goto error;
  71
  72         ret = drm_gem_create_mmap_offset(gem_obj);
  73         if (ret) {
  74                 drm_gem_object_release(gem_obj);
  75                 goto error;
  76         }
  77
  78         return cma_obj;
  79
  80 error:
  81         kfree(cma_obj);
  82         return ERR_PTR(ret);
  83 }
  84
  85 /**
  86  * drm_gem_cma_create - allocate an object with the given size
  87  * @drm: DRM device
  88  * @size: size of the object to allocate
  89  *
  90  * This function creates a CMA GEM object and allocates a contiguous chunk of
  91  * memory as backing store. The backing memory has the writecombine attribute
  92  * set.
  93  *
  94  * Returns:
  95  * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
  96  * error code on failure.
  97  */
  98 struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
  99                                               size_t size)
 100 {
 101         struct drm_gem_cma_object *cma_obj;
 102         int ret;
 103
 104         size = round_up(size, PAGE_SIZE);
 105
 106         cma_obj = __drm_gem_cma_create(drm, size);
 107         if (IS_ERR(cma_obj))
 108                 return cma_obj;
 109
 110         cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size,
 111                         &cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN);
 112         if (!cma_obj->vaddr) {
 113                 dev_err(drm->dev, "failed to allocate buffer with size %d\n",
 114                         size);
 115                 ret = -ENOMEM;
 116                 goto error;
 117         }
 118
 119         return cma_obj;
 120
 121 error:
 122         drm_gem_cma_free_object(&cma_obj->base);
 123         return ERR_PTR(ret);
 124 }
 125 EXPORT_SYMBOL_GPL(drm_gem_cma_create);
 126
 127 /**
 128  * drm_gem_cma_create_with_handle - allocate an object with the given size and
 129  *     return a GEM handle to it
 130  * @file_priv: DRM file-private structure to register the handle for
 131  * @drm: DRM device
 132  * @size: size of the object to allocate
 133  * @handle: return location for the GEM handle
 134  *
 135  * This function creates a CMA GEM object, allocating a physically contiguous
 136  * chunk of memory as backing store. The GEM object is then added to the list
 137  * of object associated with the given file and a handle to it is returned.
 138  *
 139  * Returns:
 140  * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
 141  * error code on failure.
 142  */
 143 static struct drm_gem_cma_object *
 144 drm_gem_cma_create_with_handle(struct drm_file *file_priv,
 145                                struct drm_device *drm, size_t size,
 146                                uint32_t *handle)
 147 {
 148         struct drm_gem_cma_object *cma_obj;
 149         struct drm_gem_object *gem_obj;
 150         int ret;
 151
 152         cma_obj = drm_gem_cma_create(drm, size);
 153         if (IS_ERR(cma_obj))
 154                 return cma_obj;
 155
 156         gem_obj = &cma_obj->base;
 157
 158         /*
 159          * allocate a id of idr table where the obj is registered
 160          * and handle has the id what user can see.
 161          */
 162         ret = drm_gem_handle_create(file_priv, gem_obj, handle);
 163         if (ret)
 164                 goto err_handle_create;
 165
 166         /* drop reference from allocate - handle holds it now. */
 167         drm_gem_object_unreference_unlocked(gem_obj);
 168
 169         return cma_obj;
 170
 171 err_handle_create:
 172         drm_gem_cma_free_object(gem_obj);
 173
 174         return ERR_PTR(ret);
 175 }
 176
 177 /**
 178  * drm_gem_cma_free_object - free resources associated with a CMA GEM object
 179  * @gem_obj: GEM object to free
 180  *
 181  * This function frees the backing memory of the CMA GEM object, cleans up the
 182  * GEM object state and frees the memory used to store the object itself.
 183  * Drivers using the CMA helpers should set this as their DRM driver's
 184  * ->gem_free_object() callback.
 185  */
 186 void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
 187 {
 188         struct drm_gem_cma_object *cma_obj;
 189
 190         cma_obj = to_drm_gem_cma_obj(gem_obj);
 191
 192         if (cma_obj->vaddr) {
 193                 dma_free_writecombine(gem_obj->dev->dev, cma_obj->base.size,
 194                                       cma_obj->vaddr, cma_obj->paddr);
 195         } else if (gem_obj->import_attach) {
 196                 drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
 197         }
 198
 199         drm_gem_object_release(gem_obj);
 200
 201         kfree(cma_obj);
 202 }
 203 EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
 204
 205 /**
 206  * drm_gem_cma_dumb_create_internal - create a dumb buffer object
 207  * @file_priv: DRM file-private structure to create the dumb buffer for
 208  * @drm: DRM device
 209  * @args: IOCTL data
 210  *
 211  * This aligns the pitch and size arguments to the minimum required. This is
 212  * an internal helper that can be wrapped by a driver to account for hardware
 213  * with more specific alignment requirements. It should not be used directly
 214  * as the ->dumb_create() callback in a DRM driver.
 215  *
 216  * Returns:
 217  * 0 on success or a negative error code on failure.
 218  */
 219 int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv,
 220                                      struct drm_device *drm,
 221                                      struct drm_mode_create_dumb *args)
 222 {
 223         unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 224         struct drm_gem_cma_object *cma_obj;
 225
 226         if (args->pitch < min_pitch)
 227                 args->pitch = min_pitch;
 228
 229         if (args->size < args->pitch * args->height)
 230                 args->size = args->pitch * args->height;
 231
 232         cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
 233                                                  &args->handle);
 234         return PTR_ERR_OR_ZERO(cma_obj);
 235 }
 236 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create_internal);
 237
 238 /**
 239  * drm_gem_cma_dumb_create - create a dumb buffer object
 240  * @file_priv: DRM file-private structure to create the dumb buffer for
 241  * @drm: DRM device
 242  * @args: IOCTL data
 243  *
 244  * This function computes the pitch of the dumb buffer and rounds it up to an
 245  * integer number of bytes per pixel. Drivers for hardware that doesn't have
 246  * any additional restrictions on the pitch can directly use this function as
 247  * their ->dumb_create() callback.
 248  *
 249  * For hardware with additional restrictions, drivers can adjust the fields
 250  * set up by userspace and pass the IOCTL data along to the
 251  * drm_gem_cma_dumb_create_internal() function.
 252  *
 253  * Returns:
 254  * 0 on success or a negative error code on failure.
 255  */
 256 int drm_gem_cma_dumb_create(struct drm_file *file_priv,
 257                             struct drm_device *drm,
 258                             struct drm_mode_create_dumb *args)
 259 {
 260         struct drm_gem_cma_object *cma_obj;
 261
 262         args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 263         args->size = args->pitch * args->height;
 264
 265         cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
 266                                                  &args->handle);
 267         return PTR_ERR_OR_ZERO(cma_obj);
 268 }
 269 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
 270
 271 /**
 272  * drm_gem_cma_dumb_map_offset - return the fake mmap offset for a CMA GEM
 273  *     object
 274  * @file_priv: DRM file-private structure containing the GEM object
 275  * @drm: DRM device
 276  * @handle: GEM object handle
 277  * @offset: return location for the fake mmap offset
 278  *
 279  * This function look up an object by its handle and returns the fake mmap
 280  * offset associated with it. Drivers using the CMA helpers should set this
 281  * as their DRM driver's ->dumb_map_offset() callback.
 282  *
 283  * Returns:
 284  * 0 on success or a negative error code on failure.
 285  */
 286 int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
 287                                 struct drm_device *drm, u32 handle,
 288                                 u64 *offset)
 289 {
 290         struct drm_gem_object *gem_obj;
 291
 292         mutex_lock(&drm->struct_mutex);
 293
 294         gem_obj = drm_gem_object_lookup(drm, file_priv, handle);
 295         if (!gem_obj) {
 296                 dev_err(drm->dev, "failed to lookup GEM object\n");
 297                 mutex_unlock(&drm->struct_mutex);
 298                 return -EINVAL;
 299         }
 300
 301         *offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
 302
 303         drm_gem_object_unreference(gem_obj);
 304
 305         mutex_unlock(&drm->struct_mutex);
 306
 307         return 0;
 308 }
 309 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset);
 310
 311 const struct vm_operations_struct drm_gem_cma_vm_ops = {
 312         .open = drm_gem_vm_open,
 313         .close = drm_gem_vm_close,
 314 };
 315 EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
 316
 317 static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
 318                                 struct vm_area_struct *vma)
 319 {
 320         int ret;
 321
 322         /*
 323          * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
 324          * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
 325          * the whole buffer.
 326          */
 327         vma->vm_flags &= ~VM_PFNMAP;
 328         vma->vm_pgoff = 0;
 329
 330         ret = dma_mmap_writecombine(cma_obj->base.dev->dev, vma,
 331                                     cma_obj->vaddr, cma_obj->paddr,
 332                                     vma->vm_end - vma->vm_start);
 333         if (ret)
 334                 drm_gem_vm_close(vma);
 335
 336         return ret;
 337 }
 338
 339 /**
 340  * drm_gem_cma_mmap - memory-map a CMA GEM object
 341  * @filp: file object
 342  * @vma: VMA for the area to be mapped
 343  *
 344  * This function implements an augmented version of the GEM DRM file mmap
 345  * operation for CMA objects: In addition to the usual GEM VMA setup it
 346  * immediately faults in the entire object instead of using on-demaind
 347  * faulting. Drivers which employ the CMA helpers should use this function
 348  * as their ->mmap() handler in the DRM device file's file_operations
 349  * structure.
 350  *
 351  * Returns:
 352  * 0 on success or a negative error code on failure.
 353  */
 354 int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
 355 {
 356         struct drm_gem_cma_object *cma_obj;
 357         struct drm_gem_object *gem_obj;
 358         int ret;
 359
 360         ret = drm_gem_mmap(filp, vma);
 361         if (ret)
 362                 return ret;
 363
 364         gem_obj = vma->vm_private_data;
 365         cma_obj = to_drm_gem_cma_obj(gem_obj);
 366
 367         return drm_gem_cma_mmap_obj(cma_obj, vma);
 368 }
 369 EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
 370
 371 #ifdef CONFIG_DEBUG_FS
 372 /**
 373  * drm_gem_cma_describe - describe a CMA GEM object for debugfs
 374  * @cma_obj: CMA GEM object
 375  * @m: debugfs file handle
 376  *
 377  * This function can be used to dump a human-readable representation of the
 378  * CMA GEM object into a synthetic file.
 379  */
 380 void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj,
 381                           struct seq_file *m)
 382 {
 383         struct drm_gem_object *obj = &cma_obj->base;
 384         struct drm_device *dev = obj->dev;
 385         uint64_t off;
 386
 387         WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 388
 389         off = drm_vma_node_start(&obj->vma_node);
 390
 391         seq_printf(m, "%2d (%2d) %08llx %pad %p %d",
 392                         obj->name, obj->refcount.refcount.counter,
 393                         off, &cma_obj->paddr, cma_obj->vaddr, obj->size);
 394
 395         seq_printf(m, "\n");
 396 }
 397 EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
 398 #endif
 399
 400 /**
 401  * drm_gem_cma_prime_get_sg_table - provide a scatter/gather table of pinned
 402  *     pages for a CMA GEM object
 403  * @obj: GEM object
 404  *
 405  * This function exports a scatter/gather table suitable for PRIME usage by
 406  * calling the standard DMA mapping API. Drivers using the CMA helpers should
 407  * set this as their DRM driver's ->gem_prime_get_sg_table() callback.
 408  *
 409  * Returns:
 410  * A pointer to the scatter/gather table of pinned pages or NULL on failure.
 411  */
 412 struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj)
 413 {
 414         struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
 415         struct sg_table *sgt;
 416         int ret;
 417
 418         sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 419         if (!sgt)
 420                 return NULL;
 421
 422         ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr,
 423                               cma_obj->paddr, obj->size);
 424         if (ret < 0)
 425                 goto out;
 426
 427         return sgt;
 428
 429 out:
 430         kfree(sgt);
 431         return NULL;
 432 }
 433 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table);
 434
 435 /**
 436  * drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another
 437  *     driver's scatter/gather table of pinned pages
 438  * @dev: device to import into
 439  * @attach: DMA-BUF attachment
 440  * @sgt: scatter/gather table of pinned pages
 441  *
 442  * This function imports a scatter/gather table exported via DMA-BUF by
 443  * another driver. Imported buffers must be physically contiguous in memory
 444  * (i.e. the scatter/gather table must contain a single entry). Drivers that
 445  * use the CMA helpers should set this as their DRM driver's
 446  * ->gem_prime_import_sg_table() callback.
 447  *
 448  * Returns:
 449  * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
 450  * error code on failure.
 451  */
 452 struct drm_gem_object *
 453 drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
 454                                   struct dma_buf_attachment *attach,
 455                                   struct sg_table *sgt)
 456 {
 457         struct drm_gem_cma_object *cma_obj;
 458
 459         if (sgt->nents != 1)
 460                 return ERR_PTR(-EINVAL);
 461
 462         /* Create a CMA GEM buffer. */
 463         cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size);
 464         if (IS_ERR(cma_obj))
 465                 return ERR_CAST(cma_obj);
 466
 467         cma_obj->paddr = sg_dma_address(sgt->sgl);
 468         cma_obj->sgt = sgt;
 469
 470         DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size);
 471
 472         return &cma_obj->base;
 473 }
 474 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
 475
 476 /**
 477  * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
 478  * @obj: GEM object
 479  * @vma: VMA for the area to be mapped
 480  *
 481  * This function maps a buffer imported via DRM PRIME into a userspace
 482  * process's address space. Drivers that use the CMA helpers should set this
 483  * as their DRM driver's ->gem_prime_mmap() callback.
 484  *
 485  * Returns:
 486  * 0 on success or a negative error code on failure.
 487  */
 488 int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
 489                            struct vm_area_struct *vma)
 490 {
 491         struct drm_gem_cma_object *cma_obj;
 492         struct drm_device *dev = obj->dev;
 493         int ret;
 494
 495         mutex_lock(&dev->struct_mutex);
 496         ret = drm_gem_mmap_obj(obj, obj->size, vma);
 497         mutex_unlock(&dev->struct_mutex);
 498         if (ret < 0)
 499                 return ret;
 500
 501         cma_obj = to_drm_gem_cma_obj(obj);
 502         return drm_gem_cma_mmap_obj(cma_obj, vma);
 503 }
 504 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
 505
 506 /**
 507  * drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual
 508  *     address space
 509  * @obj: GEM object
 510  *
 511  * This function maps a buffer exported via DRM PRIME into the kernel's
 512  * virtual address space. Since the CMA buffers are already mapped into the
 513  * kernel virtual address space this simply returns the cached virtual
 514  * address. Drivers using the CMA helpers should set this as their DRM
 515  * driver's ->gem_prime_vmap() callback.
 516  *
 517  * Returns:
 518  * The kernel virtual address of the CMA GEM object's backing store.
 519  */
 520 void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
 521 {
 522         struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
 523
 524         return cma_obj->vaddr;
 525 }
 526 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
 527
 528 /**
 529  * drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual
 530  *     address space
 531  * @obj: GEM object
 532  * @vaddr: kernel virtual address where the CMA GEM object was mapped
 533  *
 534  * This function removes a buffer exported via DRM PRIME from the kernel's
 535  * virtual address space. This is a no-op because CMA buffers cannot be
 536  * unmapped from kernel space. Drivers using the CMA helpers should set this
 537  * as their DRM driver's ->gem_prime_vunmap() callback.
 538  */
 539 void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
 540 {
 541         /* Nothing to do */
 542 }
 543 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);