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         drm_gem_free_mmap_offset(gem_obj);
 191
 192         cma_obj = to_drm_gem_cma_obj(gem_obj);
 193
 194         if (cma_obj->vaddr) {
 195                 dma_free_writecombine(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 - 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 function computes the pitch of the dumb buffer and rounds it up to an
 214  * integer number of bytes per pixel. Drivers for hardware that doesn't have
 215  * any additional restrictions on the pitch can directly use this function as
 216  * their ->dumb_create() callback.
 217  *
 218  * Returns:
 219  * 0 on success or a negative error code on failure.
 220  */
 221 int drm_gem_cma_dumb_create(struct drm_file *file_priv,
 222                             struct drm_device *drm,
 223                             struct drm_mode_create_dumb *args)
 224 {
 225         struct drm_gem_cma_object *cma_obj;
 226         int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 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);
 239
 240 /**
 241  * drm_gem_cma_dumb_map_offset - return the fake mmap offset for a CMA GEM
 242  *     object
 243  * @file_priv: DRM file-private structure containing the GEM object
 244  * @drm: DRM device
 245  * @handle: GEM object handle
 246  * @offset: return location for the fake mmap offset
 247  *
 248  * This function look up an object by its handle and returns the fake mmap
 249  * offset associated with it. Drivers using the CMA helpers should set this
 250  * as their DRM driver's ->dumb_map_offset() callback.
 251  *
 252  * Returns:
 253  * 0 on success or a negative error code on failure.
 254  */
 255 int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
 256                                 struct drm_device *drm, u32 handle,
 257                                 u64 *offset)
 258 {
 259         struct drm_gem_object *gem_obj;
 260
 261         mutex_lock(&drm->struct_mutex);
 262
 263         gem_obj = drm_gem_object_lookup(drm, file_priv, handle);
 264         if (!gem_obj) {
 265                 dev_err(drm->dev, "failed to lookup GEM object\n");
 266                 mutex_unlock(&drm->struct_mutex);
 267                 return -EINVAL;
 268         }
 269
 270         *offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
 271
 272         drm_gem_object_unreference(gem_obj);
 273
 274         mutex_unlock(&drm->struct_mutex);
 275
 276         return 0;
 277 }
 278 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset);
 279
 280 const struct vm_operations_struct drm_gem_cma_vm_ops = {
 281         .open = drm_gem_vm_open,
 282         .close = drm_gem_vm_close,
 283 };
 284 EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
 285
 286 static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
 287                                 struct vm_area_struct *vma)
 288 {
 289         int ret;
 290
 291         /*
 292          * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
 293          * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
 294          * the whole buffer.
 295          */
 296         vma->vm_flags &= ~VM_PFNMAP;
 297         vma->vm_pgoff = 0;
 298
 299         ret = dma_mmap_writecombine(cma_obj->base.dev->dev, vma,
 300                                     cma_obj->vaddr, cma_obj->paddr,
 301                                     vma->vm_end - vma->vm_start);
 302         if (ret)
 303                 drm_gem_vm_close(vma);
 304
 305         return ret;
 306 }
 307
 308 /**
 309  * drm_gem_cma_mmap - memory-map a CMA GEM object
 310  * @filp: file object
 311  * @vma: VMA for the area to be mapped
 312  *
 313  * This function implements an augmented version of the GEM DRM file mmap
 314  * operation for CMA objects: In addition to the usual GEM VMA setup it
 315  * immediately faults in the entire object instead of using on-demaind
 316  * faulting. Drivers which employ the CMA helpers should use this function
 317  * as their ->mmap() handler in the DRM device file's file_operations
 318  * structure.
 319  *
 320  * Returns:
 321  * 0 on success or a negative error code on failure.
 322  */
 323 int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
 324 {
 325         struct drm_gem_cma_object *cma_obj;
 326         struct drm_gem_object *gem_obj;
 327         int ret;
 328
 329         ret = drm_gem_mmap(filp, vma);
 330         if (ret)
 331                 return ret;
 332
 333         gem_obj = vma->vm_private_data;
 334         cma_obj = to_drm_gem_cma_obj(gem_obj);
 335
 336         return drm_gem_cma_mmap_obj(cma_obj, vma);
 337 }
 338 EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
 339
 340 #ifdef CONFIG_DEBUG_FS
 341 /**
 342  * drm_gem_cma_describe - describe a CMA GEM object for debugfs
 343  * @cma_obj: CMA GEM object
 344  * @m: debugfs file handle
 345  *
 346  * This function can be used to dump a human-readable representation of the
 347  * CMA GEM object into a synthetic file.
 348  */
 349 void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj,
 350                           struct seq_file *m)
 351 {
 352         struct drm_gem_object *obj = &cma_obj->base;
 353         struct drm_device *dev = obj->dev;
 354         uint64_t off;
 355
 356         WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 357
 358         off = drm_vma_node_start(&obj->vma_node);
 359
 360         seq_printf(m, "%2d (%2d) %08llx %pad %p %d",
 361                         obj->name, obj->refcount.refcount.counter,
 362                         off, &cma_obj->paddr, cma_obj->vaddr, obj->size);
 363
 364         seq_printf(m, "\n");
 365 }
 366 EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
 367 #endif
 368
 369 /**
 370  * drm_gem_cma_prime_get_sg_table - provide a scatter/gather table of pinned
 371  *     pages for a CMA GEM object
 372  * @obj: GEM object
 373  *
 374  * This function exports a scatter/gather table suitable for PRIME usage by
 375  * calling the standard DMA mapping API. Drivers using the CMA helpers should
 376  * set this as their DRM driver's ->gem_prime_get_sg_table() callback.
 377  *
 378  * Returns:
 379  * A pointer to the scatter/gather table of pinned pages or NULL on failure.
 380  */
 381 struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj)
 382 {
 383         struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
 384         struct sg_table *sgt;
 385         int ret;
 386
 387         sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 388         if (!sgt)
 389                 return NULL;
 390
 391         ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr,
 392                               cma_obj->paddr, obj->size);
 393         if (ret < 0)
 394                 goto out;
 395
 396         return sgt;
 397
 398 out:
 399         kfree(sgt);
 400         return NULL;
 401 }
 402 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table);
 403
 404 /**
 405  * drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another
 406  *     driver's scatter/gather table of pinned pages
 407  * @dev: device to import into
 408  * @attach: DMA-BUF attachment
 409  * @sgt: scatter/gather table of pinned pages
 410  *
 411  * This function imports a scatter/gather table exported via DMA-BUF by
 412  * another driver. Imported buffers must be physically contiguous in memory
 413  * (i.e. the scatter/gather table must contain a single entry). Drivers that
 414  * use the CMA helpers should set this as their DRM driver's
 415  * ->gem_prime_import_sg_table() callback.
 416  *
 417  * Returns:
 418  * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
 419  * error code on failure.
 420  */
 421 struct drm_gem_object *
 422 drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
 423                                   struct dma_buf_attachment *attach,
 424                                   struct sg_table *sgt)
 425 {
 426         struct drm_gem_cma_object *cma_obj;
 427
 428         if (sgt->nents != 1)
 429                 return ERR_PTR(-EINVAL);
 430
 431         /* Create a CMA GEM buffer. */
 432         cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size);
 433         if (IS_ERR(cma_obj))
 434                 return ERR_CAST(cma_obj);
 435
 436         cma_obj->paddr = sg_dma_address(sgt->sgl);
 437         cma_obj->sgt = sgt;
 438
 439         DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size);
 440
 441         return &cma_obj->base;
 442 }
 443 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
 444
 445 /**
 446  * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
 447  * @obj: GEM object
 448  * @vma: VMA for the area to be mapped
 449  *
 450  * This function maps a buffer imported via DRM PRIME into a userspace
 451  * process's address space. Drivers that use the CMA helpers should set this
 452  * as their DRM driver's ->gem_prime_mmap() callback.
 453  *
 454  * Returns:
 455  * 0 on success or a negative error code on failure.
 456  */
 457 int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
 458                            struct vm_area_struct *vma)
 459 {
 460         struct drm_gem_cma_object *cma_obj;
 461         struct drm_device *dev = obj->dev;
 462         int ret;
 463
 464         mutex_lock(&dev->struct_mutex);
 465         ret = drm_gem_mmap_obj(obj, obj->size, vma);
 466         mutex_unlock(&dev->struct_mutex);
 467         if (ret < 0)
 468                 return ret;
 469
 470         cma_obj = to_drm_gem_cma_obj(obj);
 471         return drm_gem_cma_mmap_obj(cma_obj, vma);
 472 }
 473 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
 474
 475 /**
 476  * drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual
 477  *     address space
 478  * @obj: GEM object
 479  *
 480  * This function maps a buffer exported via DRM PRIME into the kernel's
 481  * virtual address space. Since the CMA buffers are already mapped into the
 482  * kernel virtual address space this simply returns the cached virtual
 483  * address. Drivers using the CMA helpers should set this as their DRM
 484  * driver's ->gem_prime_vmap() callback.
 485  *
 486  * Returns:
 487  * The kernel virtual address of the CMA GEM object's backing store.
 488  */
 489 void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
 490 {
 491         struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
 492
 493         return cma_obj->vaddr;
 494 }
 495 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
 496
 497 /**
 498  * drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual
 499  *     address space
 500  * @obj: GEM object
 501  * @vaddr: kernel virtual address where the CMA GEM object was mapped
 502  *
 503  * This function removes a buffer exported via DRM PRIME from the kernel's
 504  * virtual address space. This is a no-op because CMA buffers cannot be
 505  * unmapped from kernel space. Drivers using the CMA helpers should set this
 506  * as their DRM driver's ->gem_prime_vunmap() callback.
 507  */
 508 void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
 509 {
 510         /* Nothing to do */
 511 }
 512 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);