1/*
   2 * Copyright © 2012 Red Hat
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice (including the next
  12 * paragraph) shall be included in all copies or substantial portions of the
  13 * Software.
  14 *
  15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21 * IN THE SOFTWARE.
  22 *
  23 * Authors:
  24 *      Dave Airlie <airlied@redhat.com>
  25 *      Rob Clark <rob.clark@linaro.org>
  26 *
  27 */
  28
  29#include <linux/export.h>
  30#include <linux/dma-buf.h>
  31#include <linux/rbtree.h>
 
  32
  33#include <drm/drm.h>
  34#include <drm/drm_drv.h>
  35#include <drm/drm_file.h>
  36#include <drm/drm_framebuffer.h>
  37#include <drm/drm_gem.h>
  38#include <drm/drm_prime.h>
  39
  40#include "drm_internal.h"
  41
 
 
  42/**
  43 * DOC: overview and lifetime rules
  44 *
  45 * Similar to GEM global names, PRIME file descriptors are also used to share
  46 * buffer objects across processes. They offer additional security: as file
  47 * descriptors must be explicitly sent over UNIX domain sockets to be shared
  48 * between applications, they can't be guessed like the globally unique GEM
  49 * names.
  50 *
  51 * Drivers that support the PRIME API implement the
  52 * &drm_driver.prime_handle_to_fd and &drm_driver.prime_fd_to_handle operations.
  53 * GEM based drivers must use drm_gem_prime_handle_to_fd() and
  54 * drm_gem_prime_fd_to_handle() to implement these. For GEM based drivers the
  55 * actual driver interfaces is provided through the &drm_gem_object_funcs.export
  56 * and &drm_driver.gem_prime_import hooks.
  57 *
  58 * &dma_buf_ops implementations for GEM drivers are all individually exported
  59 * for drivers which need to overwrite or reimplement some of them.
  60 *
  61 * Reference Counting for GEM Drivers
  62 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  63 *
  64 * On the export the &dma_buf holds a reference to the exported buffer object,
  65 * usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
  66 * IOCTL, when it first calls &drm_gem_object_funcs.export
  67 * and stores the exporting GEM object in the &dma_buf.priv field. This
  68 * reference needs to be released when the final reference to the &dma_buf
  69 * itself is dropped and its &dma_buf_ops.release function is called.  For
  70 * GEM-based drivers, the &dma_buf should be exported using
  71 * drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
  72 *
  73 * Thus the chain of references always flows in one direction, avoiding loops:
  74 * importing GEM object -> dma-buf -> exported GEM bo. A further complication
  75 * are the lookup caches for import and export. These are required to guarantee
  76 * that any given object will always have only one uniqe userspace handle. This
  77 * is required to allow userspace to detect duplicated imports, since some GEM
  78 * drivers do fail command submissions if a given buffer object is listed more
  79 * than once. These import and export caches in &drm_prime_file_private only
  80 * retain a weak reference, which is cleaned up when the corresponding object is
  81 * released.
  82 *
  83 * Self-importing: If userspace is using PRIME as a replacement for flink then
  84 * it will get a fd->handle request for a GEM object that it created.  Drivers
  85 * should detect this situation and return back the underlying object from the
  86 * dma-buf private. For GEM based drivers this is handled in
  87 * drm_gem_prime_import() already.
  88 */
  89
  90struct drm_prime_member {
  91	struct dma_buf *dma_buf;
  92	uint32_t handle;
  93
  94	struct rb_node dmabuf_rb;
  95	struct rb_node handle_rb;
  96};
  97
  98static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
  99				    struct dma_buf *dma_buf, uint32_t handle)
 100{
 101	struct drm_prime_member *member;
 102	struct rb_node **p, *rb;
 103
 104	member = kmalloc(sizeof(*member), GFP_KERNEL);
 105	if (!member)
 106		return -ENOMEM;
 107
 108	get_dma_buf(dma_buf);
 109	member->dma_buf = dma_buf;
 110	member->handle = handle;
 111
 112	rb = NULL;
 113	p = &prime_fpriv->dmabufs.rb_node;
 114	while (*p) {
 115		struct drm_prime_member *pos;
 116
 117		rb = *p;
 118		pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
 119		if (dma_buf > pos->dma_buf)
 120			p = &rb->rb_right;
 121		else
 122			p = &rb->rb_left;
 123	}
 124	rb_link_node(&member->dmabuf_rb, rb, p);
 125	rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
 126
 127	rb = NULL;
 128	p = &prime_fpriv->handles.rb_node;
 129	while (*p) {
 130		struct drm_prime_member *pos;
 131
 132		rb = *p;
 133		pos = rb_entry(rb, struct drm_prime_member, handle_rb);
 134		if (handle > pos->handle)
 135			p = &rb->rb_right;
 136		else
 137			p = &rb->rb_left;
 138	}
 139	rb_link_node(&member->handle_rb, rb, p);
 140	rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
 141
 142	return 0;
 143}
 144
 145static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
 146						      uint32_t handle)
 147{
 148	struct rb_node *rb;
 149
 150	rb = prime_fpriv->handles.rb_node;
 151	while (rb) {
 152		struct drm_prime_member *member;
 153
 154		member = rb_entry(rb, struct drm_prime_member, handle_rb);
 155		if (member->handle == handle)
 156			return member->dma_buf;
 157		else if (member->handle < handle)
 158			rb = rb->rb_right;
 159		else
 160			rb = rb->rb_left;
 161	}
 162
 163	return NULL;
 164}
 165
 166static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
 167				       struct dma_buf *dma_buf,
 168				       uint32_t *handle)
 169{
 170	struct rb_node *rb;
 171
 172	rb = prime_fpriv->dmabufs.rb_node;
 173	while (rb) {
 174		struct drm_prime_member *member;
 175
 176		member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
 177		if (member->dma_buf == dma_buf) {
 178			*handle = member->handle;
 179			return 0;
 180		} else if (member->dma_buf < dma_buf) {
 181			rb = rb->rb_right;
 182		} else {
 183			rb = rb->rb_left;
 184		}
 185	}
 186
 187	return -ENOENT;
 188}
 189
 190void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
 191					struct dma_buf *dma_buf)
 192{
 193	struct rb_node *rb;
 194
 195	rb = prime_fpriv->dmabufs.rb_node;
 
 
 196	while (rb) {
 197		struct drm_prime_member *member;
 198
 199		member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
 200		if (member->dma_buf == dma_buf) {
 201			rb_erase(&member->handle_rb, &prime_fpriv->handles);
 202			rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
 203
 204			dma_buf_put(dma_buf);
 205			kfree(member);
 206			return;
 207		} else if (member->dma_buf < dma_buf) {
 208			rb = rb->rb_right;
 209		} else {
 210			rb = rb->rb_left;
 211		}
 212	}
 
 
 213}
 214
 215void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
 216{
 217	mutex_init(&prime_fpriv->lock);
 218	prime_fpriv->dmabufs = RB_ROOT;
 219	prime_fpriv->handles = RB_ROOT;
 220}
 221
 222void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
 223{
 224	/* by now drm_gem_release should've made sure the list is empty */
 225	WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
 226}
 227
 228/**
 229 * drm_gem_dmabuf_export - &dma_buf export implementation for GEM
 230 * @dev: parent device for the exported dmabuf
 231 * @exp_info: the export information used by dma_buf_export()
 232 *
 233 * This wraps dma_buf_export() for use by generic GEM drivers that are using
 234 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
 235 * a reference to the &drm_device and the exported &drm_gem_object (stored in
 236 * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
 237 *
 238 * Returns the new dmabuf.
 239 */
 240struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
 241				      struct dma_buf_export_info *exp_info)
 242{
 
 243	struct dma_buf *dma_buf;
 244
 245	dma_buf = dma_buf_export(exp_info);
 246	if (IS_ERR(dma_buf))
 247		return dma_buf;
 248
 249	drm_dev_get(dev);
 250	drm_gem_object_get(exp_info->priv);
 
 251
 252	return dma_buf;
 253}
 254EXPORT_SYMBOL(drm_gem_dmabuf_export);
 255
 256/**
 257 * drm_gem_dmabuf_release - &dma_buf release implementation for GEM
 258 * @dma_buf: buffer to be released
 259 *
 260 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
 261 * must use this in their &dma_buf_ops structure as the release callback.
 262 * drm_gem_dmabuf_release() should be used in conjunction with
 263 * drm_gem_dmabuf_export().
 264 */
 265void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
 266{
 267	struct drm_gem_object *obj = dma_buf->priv;
 268	struct drm_device *dev = obj->dev;
 269
 270	/* drop the reference on the export fd holds */
 271	drm_gem_object_put_unlocked(obj);
 272
 273	drm_dev_put(dev);
 274}
 275EXPORT_SYMBOL(drm_gem_dmabuf_release);
 276
 277/**
 278 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
 279 * @dev: dev to export the buffer from
 280 * @file_priv: drm file-private structure
 281 * @prime_fd: fd id of the dma-buf which should be imported
 282 * @handle: pointer to storage for the handle of the imported buffer object
 283 *
 284 * This is the PRIME import function which must be used mandatorily by GEM
 285 * drivers to ensure correct lifetime management of the underlying GEM object.
 286 * The actual importing of GEM object from the dma-buf is done through the
 287 * &drm_driver.gem_prime_import driver callback.
 288 *
 289 * Returns 0 on success or a negative error code on failure.
 290 */
 291int drm_gem_prime_fd_to_handle(struct drm_device *dev,
 292			       struct drm_file *file_priv, int prime_fd,
 293			       uint32_t *handle)
 294{
 295	struct dma_buf *dma_buf;
 296	struct drm_gem_object *obj;
 297	int ret;
 298
 299	dma_buf = dma_buf_get(prime_fd);
 300	if (IS_ERR(dma_buf))
 301		return PTR_ERR(dma_buf);
 302
 303	mutex_lock(&file_priv->prime.lock);
 304
 305	ret = drm_prime_lookup_buf_handle(&file_priv->prime,
 306			dma_buf, handle);
 307	if (ret == 0)
 308		goto out_put;
 309
 310	/* never seen this one, need to import */
 311	mutex_lock(&dev->object_name_lock);
 312	if (dev->driver->gem_prime_import)
 313		obj = dev->driver->gem_prime_import(dev, dma_buf);
 314	else
 315		obj = drm_gem_prime_import(dev, dma_buf);
 316	if (IS_ERR(obj)) {
 317		ret = PTR_ERR(obj);
 318		goto out_unlock;
 319	}
 320
 321	if (obj->dma_buf) {
 322		WARN_ON(obj->dma_buf != dma_buf);
 323	} else {
 324		obj->dma_buf = dma_buf;
 325		get_dma_buf(dma_buf);
 326	}
 327
 328	/* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
 329	ret = drm_gem_handle_create_tail(file_priv, obj, handle);
 330	drm_gem_object_put_unlocked(obj);
 331	if (ret)
 332		goto out_put;
 333
 334	ret = drm_prime_add_buf_handle(&file_priv->prime,
 335			dma_buf, *handle);
 336	mutex_unlock(&file_priv->prime.lock);
 337	if (ret)
 338		goto fail;
 339
 340	dma_buf_put(dma_buf);
 341
 342	return 0;
 343
 344fail:
 345	/* hmm, if driver attached, we are relying on the free-object path
 346	 * to detach.. which seems ok..
 347	 */
 348	drm_gem_handle_delete(file_priv, *handle);
 349	dma_buf_put(dma_buf);
 350	return ret;
 351
 352out_unlock:
 353	mutex_unlock(&dev->object_name_lock);
 354out_put:
 355	mutex_unlock(&file_priv->prime.lock);
 356	dma_buf_put(dma_buf);
 357	return ret;
 358}
 359EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
 360
 361int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
 362				 struct drm_file *file_priv)
 363{
 364	struct drm_prime_handle *args = data;
 365
 366	if (!dev->driver->prime_fd_to_handle)
 367		return -ENOSYS;
 
 
 368
 369	return dev->driver->prime_fd_to_handle(dev, file_priv,
 370			args->fd, &args->handle);
 371}
 372
 373static struct dma_buf *export_and_register_object(struct drm_device *dev,
 374						  struct drm_gem_object *obj,
 375						  uint32_t flags)
 376{
 377	struct dma_buf *dmabuf;
 378
 379	/* prevent races with concurrent gem_close. */
 380	if (obj->handle_count == 0) {
 381		dmabuf = ERR_PTR(-ENOENT);
 382		return dmabuf;
 383	}
 384
 385	if (obj->funcs && obj->funcs->export)
 386		dmabuf = obj->funcs->export(obj, flags);
 387	else if (dev->driver->gem_prime_export)
 388		dmabuf = dev->driver->gem_prime_export(obj, flags);
 389	else
 390		dmabuf = drm_gem_prime_export(obj, flags);
 391	if (IS_ERR(dmabuf)) {
 392		/* normally the created dma-buf takes ownership of the ref,
 393		 * but if that fails then drop the ref
 394		 */
 395		return dmabuf;
 396	}
 397
 398	/*
 399	 * Note that callers do not need to clean up the export cache
 400	 * since the check for obj->handle_count guarantees that someone
 401	 * will clean it up.
 402	 */
 403	obj->dma_buf = dmabuf;
 404	get_dma_buf(obj->dma_buf);
 405
 406	return dmabuf;
 407}
 408
 409/**
 410 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
 411 * @dev: dev to export the buffer from
 412 * @file_priv: drm file-private structure
 413 * @handle: buffer handle to export
 414 * @flags: flags like DRM_CLOEXEC
 415 * @prime_fd: pointer to storage for the fd id of the create dma-buf
 416 *
 417 * This is the PRIME export function which must be used mandatorily by GEM
 418 * drivers to ensure correct lifetime management of the underlying GEM object.
 419 * The actual exporting from GEM object to a dma-buf is done through the
 420 * &drm_driver.gem_prime_export driver callback.
 421 */
 422int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 423			       struct drm_file *file_priv, uint32_t handle,
 424			       uint32_t flags,
 425			       int *prime_fd)
 426{
 427	struct drm_gem_object *obj;
 428	int ret = 0;
 429	struct dma_buf *dmabuf;
 430
 431	mutex_lock(&file_priv->prime.lock);
 432	obj = drm_gem_object_lookup(file_priv, handle);
 433	if (!obj)  {
 434		ret = -ENOENT;
 435		goto out_unlock;
 436	}
 437
 438	dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
 439	if (dmabuf) {
 440		get_dma_buf(dmabuf);
 441		goto out_have_handle;
 442	}
 443
 444	mutex_lock(&dev->object_name_lock);
 445	/* re-export the original imported object */
 446	if (obj->import_attach) {
 447		dmabuf = obj->import_attach->dmabuf;
 448		get_dma_buf(dmabuf);
 449		goto out_have_obj;
 450	}
 451
 452	if (obj->dma_buf) {
 453		get_dma_buf(obj->dma_buf);
 454		dmabuf = obj->dma_buf;
 455		goto out_have_obj;
 456	}
 457
 458	dmabuf = export_and_register_object(dev, obj, flags);
 459	if (IS_ERR(dmabuf)) {
 460		/* normally the created dma-buf takes ownership of the ref,
 461		 * but if that fails then drop the ref
 462		 */
 463		ret = PTR_ERR(dmabuf);
 464		mutex_unlock(&dev->object_name_lock);
 465		goto out;
 466	}
 467
 468out_have_obj:
 469	/*
 470	 * If we've exported this buffer then cheat and add it to the import list
 471	 * so we get the correct handle back. We must do this under the
 472	 * protection of dev->object_name_lock to ensure that a racing gem close
 473	 * ioctl doesn't miss to remove this buffer handle from the cache.
 474	 */
 475	ret = drm_prime_add_buf_handle(&file_priv->prime,
 476				       dmabuf, handle);
 477	mutex_unlock(&dev->object_name_lock);
 478	if (ret)
 479		goto fail_put_dmabuf;
 480
 481out_have_handle:
 482	ret = dma_buf_fd(dmabuf, flags);
 483	/*
 484	 * We must _not_ remove the buffer from the handle cache since the newly
 485	 * created dma buf is already linked in the global obj->dma_buf pointer,
 486	 * and that is invariant as long as a userspace gem handle exists.
 487	 * Closing the handle will clean out the cache anyway, so we don't leak.
 488	 */
 489	if (ret < 0) {
 490		goto fail_put_dmabuf;
 491	} else {
 492		*prime_fd = ret;
 493		ret = 0;
 494	}
 495
 496	goto out;
 497
 498fail_put_dmabuf:
 499	dma_buf_put(dmabuf);
 500out:
 501	drm_gem_object_put_unlocked(obj);
 502out_unlock:
 503	mutex_unlock(&file_priv->prime.lock);
 504
 505	return ret;
 506}
 507EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
 508
 509int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 510				 struct drm_file *file_priv)
 511{
 512	struct drm_prime_handle *args = data;
 513
 514	if (!dev->driver->prime_handle_to_fd)
 515		return -ENOSYS;
 516
 517	/* check flags are valid */
 518	if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
 519		return -EINVAL;
 520
 521	return dev->driver->prime_handle_to_fd(dev, file_priv,
 522			args->handle, args->flags, &args->fd);
 
 
 
 
 
 523}
 524
 525/**
 526 * DOC: PRIME Helpers
 527 *
 528 * Drivers can implement &drm_gem_object_funcs.export and
 529 * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
 530 * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
 531 * implement dma-buf support in terms of some lower-level helpers, which are
 532 * again exported for drivers to use individually:
 533 *
 534 * Exporting buffers
 535 * ~~~~~~~~~~~~~~~~~
 536 *
 537 * Optional pinning of buffers is handled at dma-buf attach and detach time in
 538 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
 539 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
 540 * &drm_gem_object_funcs.get_sg_table.
 
 541 *
 542 * For kernel-internal access there's drm_gem_dmabuf_vmap() and
 543 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
 544 * drm_gem_dmabuf_mmap().
 545 *
 546 * Note that these export helpers can only be used if the underlying backing
 547 * storage is fully coherent and either permanently pinned, or it is safe to pin
 548 * it indefinitely.
 549 *
 550 * FIXME: The underlying helper functions are named rather inconsistently.
 551 *
 552 * Exporting buffers
 553 * ~~~~~~~~~~~~~~~~~
 554 *
 555 * Importing dma-bufs using drm_gem_prime_import() relies on
 556 * &drm_driver.gem_prime_import_sg_table.
 557 *
 558 * Note that similarly to the export helpers this permanently pins the
 559 * underlying backing storage. Which is ok for scanout, but is not the best
 560 * option for sharing lots of buffers for rendering.
 561 */
 562
 563/**
 564 * drm_gem_map_attach - dma_buf attach implementation for GEM
 565 * @dma_buf: buffer to attach device to
 566 * @attach: buffer attachment data
 567 *
 568 * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
 569 * used as the &dma_buf_ops.attach callback. Must be used together with
 570 * drm_gem_map_detach().
 571 *
 572 * Returns 0 on success, negative error code on failure.
 573 */
 574int drm_gem_map_attach(struct dma_buf *dma_buf,
 575		       struct dma_buf_attachment *attach)
 576{
 577	struct drm_gem_object *obj = dma_buf->priv;
 578
 
 
 
 
 
 
 
 
 579	return drm_gem_pin(obj);
 580}
 581EXPORT_SYMBOL(drm_gem_map_attach);
 582
 583/**
 584 * drm_gem_map_detach - dma_buf detach implementation for GEM
 585 * @dma_buf: buffer to detach from
 586 * @attach: attachment to be detached
 587 *
 588 * Calls &drm_gem_object_funcs.pin for device specific handling.  Cleans up
 589 * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
 590 * &dma_buf_ops.detach callback.
 591 */
 592void drm_gem_map_detach(struct dma_buf *dma_buf,
 593			struct dma_buf_attachment *attach)
 594{
 595	struct drm_gem_object *obj = dma_buf->priv;
 596
 597	drm_gem_unpin(obj);
 598}
 599EXPORT_SYMBOL(drm_gem_map_detach);
 600
 601/**
 602 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
 603 * @attach: attachment whose scatterlist is to be returned
 604 * @dir: direction of DMA transfer
 605 *
 606 * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
 607 * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
 608 * with drm_gem_unmap_dma_buf().
 609 *
 610 * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
 611 * on error. May return -EINTR if it is interrupted by a signal.
 612 */
 613struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
 614				     enum dma_data_direction dir)
 615{
 616	struct drm_gem_object *obj = attach->dmabuf->priv;
 617	struct sg_table *sgt;
 
 618
 619	if (WARN_ON(dir == DMA_NONE))
 620		return ERR_PTR(-EINVAL);
 621
 622	if (obj->funcs)
 623		sgt = obj->funcs->get_sg_table(obj);
 624	else
 625		sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
 626
 627	if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
 628			      DMA_ATTR_SKIP_CPU_SYNC)) {
 
 
 
 
 
 629		sg_free_table(sgt);
 630		kfree(sgt);
 631		sgt = ERR_PTR(-ENOMEM);
 632	}
 633
 634	return sgt;
 635}
 636EXPORT_SYMBOL(drm_gem_map_dma_buf);
 637
 638/**
 639 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
 640 * @attach: attachment to unmap buffer from
 641 * @sgt: scatterlist info of the buffer to unmap
 642 * @dir: direction of DMA transfer
 643 *
 644 * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
 645 */
 646void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 647			   struct sg_table *sgt,
 648			   enum dma_data_direction dir)
 649{
 650	if (!sgt)
 651		return;
 652
 653	dma_unmap_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
 654			   DMA_ATTR_SKIP_CPU_SYNC);
 655	sg_free_table(sgt);
 656	kfree(sgt);
 657}
 658EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
 659
 660/**
 661 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
 662 * @dma_buf: buffer to be mapped
 
 663 *
 664 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
 665 * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
 
 666 *
 667 * Returns the kernel virtual address or NULL on failure.
 668 */
 669void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 670{
 671	struct drm_gem_object *obj = dma_buf->priv;
 672	void *vaddr;
 673
 674	vaddr = drm_gem_vmap(obj);
 675	if (IS_ERR(vaddr))
 676		vaddr = NULL;
 677
 678	return vaddr;
 679}
 680EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
 681
 682/**
 683 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
 684 * @dma_buf: buffer to be unmapped
 685 * @vaddr: the virtual address of the buffer
 686 *
 687 * Releases a kernel virtual mapping. This can be used as the
 688 * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
 689 */
 690void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 691{
 692	struct drm_gem_object *obj = dma_buf->priv;
 693
 694	drm_gem_vunmap(obj, vaddr);
 695}
 696EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
 697
 698/**
 699 * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
 700 * @obj: GEM object
 701 * @vma: Virtual address range
 702 *
 703 * This function sets up a userspace mapping for PRIME exported buffers using
 704 * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
 705 * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
 706 * called to set up the mapping.
 707 *
 708 * Drivers can use this as their &drm_driver.gem_prime_mmap callback.
 709 */
 710int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 711{
 712	struct drm_file *priv;
 713	struct file *fil;
 714	int ret;
 715
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 716	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 717	fil = kzalloc(sizeof(*fil), GFP_KERNEL);
 718	if (!priv || !fil) {
 719		ret = -ENOMEM;
 720		goto out;
 721	}
 722
 723	/* Used by drm_gem_mmap() to lookup the GEM object */
 724	priv->minor = obj->dev->primary;
 725	fil->private_data = priv;
 726
 727	ret = drm_vma_node_allow(&obj->vma_node, priv);
 728	if (ret)
 729		goto out;
 730
 731	vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
 732
 733	ret = obj->dev->driver->fops->mmap(fil, vma);
 734
 735	drm_vma_node_revoke(&obj->vma_node, priv);
 736out:
 737	kfree(priv);
 738	kfree(fil);
 739
 740	return ret;
 741}
 742EXPORT_SYMBOL(drm_gem_prime_mmap);
 743
 744/**
 745 * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
 746 * @dma_buf: buffer to be mapped
 747 * @vma: virtual address range
 748 *
 749 * Provides memory mapping for the buffer. This can be used as the
 750 * &dma_buf_ops.mmap callback. It just forwards to &drm_driver.gem_prime_mmap,
 751 * which should be set to drm_gem_prime_mmap().
 752 *
 753 * FIXME: There's really no point to this wrapper, drivers which need anything
 754 * else but drm_gem_prime_mmap can roll their own &dma_buf_ops.mmap callback.
 755 *
 756 * Returns 0 on success or a negative error code on failure.
 757 */
 758int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
 759{
 760	struct drm_gem_object *obj = dma_buf->priv;
 761	struct drm_device *dev = obj->dev;
 762
 763	if (!dev->driver->gem_prime_mmap)
 764		return -ENOSYS;
 765
 766	return dev->driver->gem_prime_mmap(obj, vma);
 767}
 768EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
 769
 770static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 771	.cache_sgt_mapping = true,
 772	.attach = drm_gem_map_attach,
 773	.detach = drm_gem_map_detach,
 774	.map_dma_buf = drm_gem_map_dma_buf,
 775	.unmap_dma_buf = drm_gem_unmap_dma_buf,
 776	.release = drm_gem_dmabuf_release,
 777	.mmap = drm_gem_dmabuf_mmap,
 778	.vmap = drm_gem_dmabuf_vmap,
 779	.vunmap = drm_gem_dmabuf_vunmap,
 780};
 781
 782/**
 783 * drm_prime_pages_to_sg - converts a page array into an sg list
 
 784 * @pages: pointer to the array of page pointers to convert
 785 * @nr_pages: length of the page vector
 786 *
 787 * This helper creates an sg table object from a set of pages
 788 * the driver is responsible for mapping the pages into the
 789 * importers address space for use with dma_buf itself.
 790 *
 791 * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
 792 */
 793struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_pages)
 
 794{
 795	struct sg_table *sg = NULL;
 796	int ret;
 
 797
 798	sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 799	if (!sg) {
 800		ret = -ENOMEM;
 801		goto out;
 802	}
 803
 804	ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
 805				nr_pages << PAGE_SHIFT, GFP_KERNEL);
 806	if (ret)
 807		goto out;
 808
 
 
 
 
 
 
 
 
 
 
 
 809	return sg;
 810out:
 811	kfree(sg);
 812	return ERR_PTR(ret);
 813}
 814EXPORT_SYMBOL(drm_prime_pages_to_sg);
 815
 816/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 817 * drm_gem_prime_export - helper library implementation of the export callback
 818 * @obj: GEM object to export
 819 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
 820 *
 821 * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
 822 * using the PRIME helpers. It is used as the default in
 823 * drm_gem_prime_handle_to_fd().
 824 */
 825struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
 826				     int flags)
 827{
 828	struct drm_device *dev = obj->dev;
 829	struct dma_buf_export_info exp_info = {
 830		.exp_name = KBUILD_MODNAME, /* white lie for debug */
 831		.owner = dev->driver->fops->owner,
 832		.ops = &drm_gem_prime_dmabuf_ops,
 833		.size = obj->size,
 834		.flags = flags,
 835		.priv = obj,
 836		.resv = obj->resv,
 837	};
 838
 839	return drm_gem_dmabuf_export(dev, &exp_info);
 840}
 841EXPORT_SYMBOL(drm_gem_prime_export);
 842
 843/**
 844 * drm_gem_prime_import_dev - core implementation of the import callback
 845 * @dev: drm_device to import into
 846 * @dma_buf: dma-buf object to import
 847 * @attach_dev: struct device to dma_buf attach
 848 *
 849 * This is the core of drm_gem_prime_import(). It's designed to be called by
 850 * drivers who want to use a different device structure than &drm_device.dev for
 851 * attaching via dma_buf. This function calls
 852 * &drm_driver.gem_prime_import_sg_table internally.
 853 *
 854 * Drivers must arrange to call drm_prime_gem_destroy() from their
 855 * &drm_gem_object_funcs.free hook when using this function.
 856 */
 857struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
 858					    struct dma_buf *dma_buf,
 859					    struct device *attach_dev)
 860{
 861	struct dma_buf_attachment *attach;
 862	struct sg_table *sgt;
 863	struct drm_gem_object *obj;
 864	int ret;
 865
 866	if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
 867		obj = dma_buf->priv;
 868		if (obj->dev == dev) {
 869			/*
 870			 * Importing dmabuf exported from out own gem increases
 871			 * refcount on gem itself instead of f_count of dmabuf.
 872			 */
 873			drm_gem_object_get(obj);
 874			return obj;
 875		}
 876	}
 877
 878	if (!dev->driver->gem_prime_import_sg_table)
 879		return ERR_PTR(-EINVAL);
 880
 881	attach = dma_buf_attach(dma_buf, attach_dev);
 882	if (IS_ERR(attach))
 883		return ERR_CAST(attach);
 884
 885	get_dma_buf(dma_buf);
 886
 887	sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
 888	if (IS_ERR(sgt)) {
 889		ret = PTR_ERR(sgt);
 890		goto fail_detach;
 891	}
 892
 893	obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
 894	if (IS_ERR(obj)) {
 895		ret = PTR_ERR(obj);
 896		goto fail_unmap;
 897	}
 898
 899	obj->import_attach = attach;
 900	obj->resv = dma_buf->resv;
 901
 902	return obj;
 903
 904fail_unmap:
 905	dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
 906fail_detach:
 907	dma_buf_detach(dma_buf, attach);
 908	dma_buf_put(dma_buf);
 909
 910	return ERR_PTR(ret);
 911}
 912EXPORT_SYMBOL(drm_gem_prime_import_dev);
 913
 914/**
 915 * drm_gem_prime_import - helper library implementation of the import callback
 916 * @dev: drm_device to import into
 917 * @dma_buf: dma-buf object to import
 918 *
 919 * This is the implementation of the gem_prime_import functions for GEM drivers
 920 * using the PRIME helpers. Drivers can use this as their
 921 * &drm_driver.gem_prime_import implementation. It is used as the default
 922 * implementation in drm_gem_prime_fd_to_handle().
 923 *
 924 * Drivers must arrange to call drm_prime_gem_destroy() from their
 925 * &drm_gem_object_funcs.free hook when using this function.
 926 */
 927struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 928					    struct dma_buf *dma_buf)
 929{
 930	return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
 931}
 932EXPORT_SYMBOL(drm_gem_prime_import);
 933
 934/**
 935 * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 936 * @sgt: scatter-gather table to convert
 937 * @pages: optional array of page pointers to store the page array in
 938 * @addrs: optional array to store the dma bus address of each page
 939 * @max_entries: size of both the passed-in arrays
 940 *
 941 * Exports an sg table into an array of pages and addresses. This is currently
 942 * required by the TTM driver in order to do correct fault handling.
 943 *
 944 * Drivers can use this in their &drm_driver.gem_prime_import_sg_table
 945 * implementation.
 946 */
 947int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
 948				     dma_addr_t *addrs, int max_entries)
 949{
 950	unsigned count;
 951	struct scatterlist *sg;
 952	struct page *page;
 953	u32 len, index;
 954	dma_addr_t addr;
 955
 956	index = 0;
 957	for_each_sg(sgt->sgl, sg, sgt->nents, count) {
 958		len = sg->length;
 959		page = sg_page(sg);
 960		addr = sg_dma_address(sg);
 961
 962		while (len > 0) {
 963			if (WARN_ON(index >= max_entries))
 964				return -1;
 965			if (pages)
 966				pages[index] = page;
 967			if (addrs)
 968				addrs[index] = addr;
 969
 970			page++;
 971			addr += PAGE_SIZE;
 972			len -= PAGE_SIZE;
 973			index++;
 974		}
 975	}
 976	return 0;
 977}
 978EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
 979
 980/**
 981 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
 982 * @obj: GEM object which was created from a dma-buf
 983 * @sg: the sg-table which was pinned at import time
 984 *
 985 * This is the cleanup functions which GEM drivers need to call when they use
 986 * drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
 987 */
 988void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
 989{
 990	struct dma_buf_attachment *attach;
 991	struct dma_buf *dma_buf;
 
 992	attach = obj->import_attach;
 993	if (sg)
 994		dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
 995	dma_buf = attach->dmabuf;
 996	dma_buf_detach(attach->dmabuf, attach);
 997	/* remove the reference */
 998	dma_buf_put(dma_buf);
 999}
1000EXPORT_SYMBOL(drm_prime_gem_destroy);