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