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_gem_object_unreference_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_unreference_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 DRM driver's
 180  * ->gem_free_object() 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 the ->dumb_create() callback in a DRM driver.
 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 ->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 /**
 268  * drm_gem_cma_dumb_map_offset - return the fake mmap offset for a CMA GEM
 269  *     object
 270  * @file_priv: DRM file-private structure containing the GEM object
 271  * @drm: DRM device
 272  * @handle: GEM object handle
 273  * @offset: return location for the fake mmap offset
 274  *
 275  * This function look up an object by its handle and returns the fake mmap
 276  * offset associated with it. Drivers using the CMA helpers should set this
 277  * as their DRM driver's ->dumb_map_offset() callback.
 278  *
 279  * Returns:
 280  * 0 on success or a negative error code on failure.
 281  */
 282 int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
 283                                 struct drm_device *drm, u32 handle,
 284                                 u64 *offset)
 285 {
 286         struct drm_gem_object *gem_obj;
 287
 288         gem_obj = drm_gem_object_lookup(file_priv, handle);
 289         if (!gem_obj) {
 290                 dev_err(drm->dev, "failed to lookup GEM object\n");
 291                 return -EINVAL;
 292         }
 293
 294         *offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
 295
 296         drm_gem_object_unreference_unlocked(gem_obj);
 297
 298         return 0;
 299 }
 300 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset);
 301
 302 const struct vm_operations_struct drm_gem_cma_vm_ops = {
 303         .open = drm_gem_vm_open,
 304         .close = drm_gem_vm_close,
 305 };
 306 EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
 307
 308 static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
 309                                 struct vm_area_struct *vma)
 310 {
 311         int ret;
 312
 313         /*
 314          * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
 315          * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
 316          * the whole buffer.
 317          */
 318         vma->vm_flags &= ~VM_PFNMAP;
 319         vma->vm_pgoff = 0;
 320
 321         ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
 322                           cma_obj->paddr, vma->vm_end - vma->vm_start);
 323         if (ret)
 324                 drm_gem_vm_close(vma);
 325
 326         return ret;
 327 }
 328
 329 /**
 330  * drm_gem_cma_mmap - memory-map a CMA GEM object
 331  * @filp: file object
 332  * @vma: VMA for the area to be mapped
 333  *
 334  * This function implements an augmented version of the GEM DRM file mmap
 335  * operation for CMA objects: In addition to the usual GEM VMA setup it
 336  * immediately faults in the entire object instead of using on-demaind
 337  * faulting. Drivers which employ the CMA helpers should use this function
 338  * as their ->mmap() handler in the DRM device file's file_operations
 339  * structure.
 340  *
 341  * Returns:
 342  * 0 on success or a negative error code on failure.
 343  */
 344 int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
 345 {
 346         struct drm_gem_cma_object *cma_obj;
 347         struct drm_gem_object *gem_obj;
 348         int ret;
 349
 350         ret = drm_gem_mmap(filp, vma);
 351         if (ret)
 352                 return ret;
 353
 354         gem_obj = vma->vm_private_data;
 355         cma_obj = to_drm_gem_cma_obj(gem_obj);
 356
 357         return drm_gem_cma_mmap_obj(cma_obj, vma);
 358 }
 359 EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
 360
 361 #ifdef CONFIG_DEBUG_FS
 362 /**
 363  * drm_gem_cma_describe - describe a CMA GEM object for debugfs
 364  * @cma_obj: CMA GEM object
 365  * @m: debugfs file handle
 366  *
 367  * This function can be used to dump a human-readable representation of the
 368  * CMA GEM object into a synthetic file.
 369  */
 370 void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj,
 371                           struct seq_file *m)
 372 {
 373         struct drm_gem_object *obj = &cma_obj->base;
 374         uint64_t off;
 375
 376         off = drm_vma_node_start(&obj->vma_node);
 377
 378         seq_printf(m, "%2d (%2d) %08llx %pad %p %zu",
 379                         obj->name, obj->refcount.refcount.counter,
 380                         off, &cma_obj->paddr, cma_obj->vaddr, obj->size);
 381
 382         seq_printf(m, "\n");
 383 }
 384 EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
 385 #endif
 386
 387 /**
 388  * drm_gem_cma_prime_get_sg_table - provide a scatter/gather table of pinned
 389  *     pages for a CMA GEM object
 390  * @obj: GEM object
 391  *
 392  * This function exports a scatter/gather table suitable for PRIME usage by
 393  * calling the standard DMA mapping API. Drivers using the CMA helpers should
 394  * set this as their DRM driver's ->gem_prime_get_sg_table() callback.
 395  *
 396  * Returns:
 397  * A pointer to the scatter/gather table of pinned pages or NULL on failure.
 398  */
 399 struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj)
 400 {
 401         struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
 402         struct sg_table *sgt;
 403         int ret;
 404
 405         sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 406         if (!sgt)
 407                 return NULL;
 408
 409         ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr,
 410                               cma_obj->paddr, obj->size);
 411         if (ret < 0)
 412                 goto out;
 413
 414         return sgt;
 415
 416 out:
 417         kfree(sgt);
 418         return NULL;
 419 }
 420 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table);
 421
 422 /**
 423  * drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another
 424  *     driver's scatter/gather table of pinned pages
 425  * @dev: device to import into
 426  * @attach: DMA-BUF attachment
 427  * @sgt: scatter/gather table of pinned pages
 428  *
 429  * This function imports a scatter/gather table exported via DMA-BUF by
 430  * another driver. Imported buffers must be physically contiguous in memory
 431  * (i.e. the scatter/gather table must contain a single entry). Drivers that
 432  * use the CMA helpers should set this as their DRM driver's
 433  * ->gem_prime_import_sg_table() callback.
 434  *
 435  * Returns:
 436  * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
 437  * error code on failure.
 438  */
 439 struct drm_gem_object *
 440 drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
 441                                   struct dma_buf_attachment *attach,
 442                                   struct sg_table *sgt)
 443 {
 444         struct drm_gem_cma_object *cma_obj;
 445
 446         if (sgt->nents != 1)
 447                 return ERR_PTR(-EINVAL);
 448
 449         /* Create a CMA GEM buffer. */
 450         cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size);
 451         if (IS_ERR(cma_obj))
 452                 return ERR_CAST(cma_obj);
 453
 454         cma_obj->paddr = sg_dma_address(sgt->sgl);
 455         cma_obj->sgt = sgt;
 456
 457         DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size);
 458
 459         return &cma_obj->base;
 460 }
 461 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
 462
 463 /**
 464  * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
 465  * @obj: GEM object
 466  * @vma: VMA for the area to be mapped
 467  *
 468  * This function maps a buffer imported via DRM PRIME into a userspace
 469  * process's address space. Drivers that use the CMA helpers should set this
 470  * as their DRM driver's ->gem_prime_mmap() callback.
 471  *
 472  * Returns:
 473  * 0 on success or a negative error code on failure.
 474  */
 475 int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
 476                            struct vm_area_struct *vma)
 477 {
 478         struct drm_gem_cma_object *cma_obj;
 479         int ret;
 480
 481         ret = drm_gem_mmap_obj(obj, obj->size, vma);
 482         if (ret < 0)
 483                 return ret;
 484
 485         cma_obj = to_drm_gem_cma_obj(obj);
 486         return drm_gem_cma_mmap_obj(cma_obj, vma);
 487 }
 488 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
 489
 490 /**
 491  * drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual
 492  *     address space
 493  * @obj: GEM object
 494  *
 495  * This function maps a buffer exported via DRM PRIME into the kernel's
 496  * virtual address space. Since the CMA buffers are already mapped into the
 497  * kernel virtual address space this simply returns the cached virtual
 498  * address. Drivers using the CMA helpers should set this as their DRM
 499  * driver's ->gem_prime_vmap() callback.
 500  *
 501  * Returns:
 502  * The kernel virtual address of the CMA GEM object's backing store.
 503  */
 504 void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
 505 {
 506         struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
 507
 508         return cma_obj->vaddr;
 509 }
 510 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
 511
 512 /**
 513  * drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual
 514  *     address space
 515  * @obj: GEM object
 516  * @vaddr: kernel virtual address where the CMA GEM object was mapped
 517  *
 518  * This function removes a buffer exported via DRM PRIME from the kernel's
 519  * virtual address space. This is a no-op because CMA buffers cannot be
 520  * unmapped from kernel space. Drivers using the CMA helpers should set this
 521  * as their DRM driver's ->gem_prime_vunmap() callback.
 522  */
 523 void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
 524 {
 525         /* Nothing to do */
 526 }
 527 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);