1 /* exynos_drm_gem.c
2  *
3  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
4  * Author: Inki Dae <inki.dae@samsung.com>
5  *
6  * This program is free software; you can redistribute  it and/or modify it
7  * under  the terms of  the GNU General  Public License as published by the
8  * Free Software Foundation;  either version 2 of the  License, or (at your
9  * option) any later version.
10  */
11 
12 #include <drm/drmP.h>
13 
14 #include <linux/shmem_fs.h>
15 #include <drm/exynos_drm.h>
16 
17 #include "exynos_drm_drv.h"
18 #include "exynos_drm_gem.h"
19 #include "exynos_drm_buf.h"
20 
21 static unsigned int convert_to_vm_err_msg(int msg)
22 {
23 	unsigned int out_msg;
24 
25 	switch (msg) {
26 	case 0:
27 	case -ERESTARTSYS:
28 	case -EINTR:
29 		out_msg = VM_FAULT_NOPAGE;
30 		break;
31 
32 	case -ENOMEM:
33 		out_msg = VM_FAULT_OOM;
34 		break;
35 
36 	default:
37 		out_msg = VM_FAULT_SIGBUS;
38 		break;
39 	}
40 
41 	return out_msg;
42 }
43 
44 static int check_gem_flags(unsigned int flags)
45 {
46 	if (flags & ~(EXYNOS_BO_MASK)) {
47 		DRM_ERROR("invalid flags.\n");
48 		return -EINVAL;
49 	}
50 
51 	return 0;
52 }
53 
54 static void update_vm_cache_attr(struct exynos_drm_gem_obj *obj,
55 					struct vm_area_struct *vma)
56 {
57 	DRM_DEBUG_KMS("flags = 0x%x\n", obj->flags);
58 
59 	/* non-cachable as default. */
60 	if (obj->flags & EXYNOS_BO_CACHABLE)
61 		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
62 	else if (obj->flags & EXYNOS_BO_WC)
63 		vma->vm_page_prot =
64 			pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
65 	else
66 		vma->vm_page_prot =
67 			pgprot_noncached(vm_get_page_prot(vma->vm_flags));
68 }
69 
70 static unsigned long roundup_gem_size(unsigned long size, unsigned int flags)
71 {
72 	/* TODO */
73 
74 	return roundup(size, PAGE_SIZE);
75 }
76 
77 static int exynos_drm_gem_map_buf(struct drm_gem_object *obj,
78 					struct vm_area_struct *vma,
79 					unsigned long f_vaddr,
80 					pgoff_t page_offset)
81 {
82 	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
83 	struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;
84 	struct scatterlist *sgl;
85 	unsigned long pfn;
86 	int i;
87 
88 	if (!buf->sgt)
89 		return -EINTR;
90 
91 	if (page_offset >= (buf->size >> PAGE_SHIFT)) {
92 		DRM_ERROR("invalid page offset\n");
93 		return -EINVAL;
94 	}
95 
96 	sgl = buf->sgt->sgl;
97 	for_each_sg(buf->sgt->sgl, sgl, buf->sgt->nents, i) {
98 		if (page_offset < (sgl->length >> PAGE_SHIFT))
99 			break;
100 		page_offset -=	(sgl->length >> PAGE_SHIFT);
101 	}
102 
103 	pfn = __phys_to_pfn(sg_phys(sgl)) + page_offset;
104 
105 	return vm_insert_mixed(vma, f_vaddr, pfn);
106 }
107 
108 static int exynos_drm_gem_handle_create(struct drm_gem_object *obj,
109 					struct drm_file *file_priv,
110 					unsigned int *handle)
111 {
112 	int ret;
113 
114 	/*
115 	 * allocate a id of idr table where the obj is registered
116 	 * and handle has the id what user can see.
117 	 */
118 	ret = drm_gem_handle_create(file_priv, obj, handle);
119 	if (ret)
120 		return ret;
121 
122 	DRM_DEBUG_KMS("gem handle = 0x%x\n", *handle);
123 
124 	/* drop reference from allocate - handle holds it now. */
125 	drm_gem_object_unreference_unlocked(obj);
126 
127 	return 0;
128 }
129 
130 void exynos_drm_gem_destroy(struct exynos_drm_gem_obj *exynos_gem_obj)
131 {
132 	struct drm_gem_object *obj;
133 	struct exynos_drm_gem_buf *buf;
134 
135 	obj = &exynos_gem_obj->base;
136 	buf = exynos_gem_obj->buffer;
137 
138 	DRM_DEBUG_KMS("handle count = %d\n", atomic_read(&obj->handle_count));
139 
140 	/*
141 	 * do not release memory region from exporter.
142 	 *
143 	 * the region will be released by exporter
144 	 * once dmabuf's refcount becomes 0.
145 	 */
146 	if (obj->import_attach)
147 		goto out;
148 
149 	exynos_drm_free_buf(obj->dev, exynos_gem_obj->flags, buf);
150 
151 out:
152 	exynos_drm_fini_buf(obj->dev, buf);
153 	exynos_gem_obj->buffer = NULL;
154 
155 	if (obj->map_list.map)
156 		drm_gem_free_mmap_offset(obj);
157 
158 	/* release file pointer to gem object. */
159 	drm_gem_object_release(obj);
160 
161 	kfree(exynos_gem_obj);
162 	exynos_gem_obj = NULL;
163 }
164 
165 unsigned long exynos_drm_gem_get_size(struct drm_device *dev,
166 						unsigned int gem_handle,
167 						struct drm_file *file_priv)
168 {
169 	struct exynos_drm_gem_obj *exynos_gem_obj;
170 	struct drm_gem_object *obj;
171 
172 	obj = drm_gem_object_lookup(dev, file_priv, gem_handle);
173 	if (!obj) {
174 		DRM_ERROR("failed to lookup gem object.\n");
175 		return 0;
176 	}
177 
178 	exynos_gem_obj = to_exynos_gem_obj(obj);
179 
180 	drm_gem_object_unreference_unlocked(obj);
181 
182 	return exynos_gem_obj->buffer->size;
183 }
184 
185 
186 struct exynos_drm_gem_obj *exynos_drm_gem_init(struct drm_device *dev,
187 						      unsigned long size)
188 {
189 	struct exynos_drm_gem_obj *exynos_gem_obj;
190 	struct drm_gem_object *obj;
191 	int ret;
192 
193 	exynos_gem_obj = kzalloc(sizeof(*exynos_gem_obj), GFP_KERNEL);
194 	if (!exynos_gem_obj) {
195 		DRM_ERROR("failed to allocate exynos gem object\n");
196 		return NULL;
197 	}
198 
199 	exynos_gem_obj->size = size;
200 	obj = &exynos_gem_obj->base;
201 
202 	ret = drm_gem_object_init(dev, obj, size);
203 	if (ret < 0) {
204 		DRM_ERROR("failed to initialize gem object\n");
205 		kfree(exynos_gem_obj);
206 		return NULL;
207 	}
208 
209 	DRM_DEBUG_KMS("created file object = 0x%x\n", (unsigned int)obj->filp);
210 
211 	return exynos_gem_obj;
212 }
213 
214 struct exynos_drm_gem_obj *exynos_drm_gem_create(struct drm_device *dev,
215 						unsigned int flags,
216 						unsigned long size)
217 {
218 	struct exynos_drm_gem_obj *exynos_gem_obj;
219 	struct exynos_drm_gem_buf *buf;
220 	int ret;
221 
222 	if (!size) {
223 		DRM_ERROR("invalid size.\n");
224 		return ERR_PTR(-EINVAL);
225 	}
226 
227 	size = roundup_gem_size(size, flags);
228 
229 	ret = check_gem_flags(flags);
230 	if (ret)
231 		return ERR_PTR(ret);
232 
233 	buf = exynos_drm_init_buf(dev, size);
234 	if (!buf)
235 		return ERR_PTR(-ENOMEM);
236 
237 	exynos_gem_obj = exynos_drm_gem_init(dev, size);
238 	if (!exynos_gem_obj) {
239 		ret = -ENOMEM;
240 		goto err_fini_buf;
241 	}
242 
243 	exynos_gem_obj->buffer = buf;
244 
245 	/* set memory type and cache attribute from user side. */
246 	exynos_gem_obj->flags = flags;
247 
248 	ret = exynos_drm_alloc_buf(dev, buf, flags);
249 	if (ret < 0)
250 		goto err_gem_fini;
251 
252 	return exynos_gem_obj;
253 
254 err_gem_fini:
255 	drm_gem_object_release(&exynos_gem_obj->base);
256 	kfree(exynos_gem_obj);
257 err_fini_buf:
258 	exynos_drm_fini_buf(dev, buf);
259 	return ERR_PTR(ret);
260 }
261 
262 int exynos_drm_gem_create_ioctl(struct drm_device *dev, void *data,
263 				struct drm_file *file_priv)
264 {
265 	struct drm_exynos_gem_create *args = data;
266 	struct exynos_drm_gem_obj *exynos_gem_obj;
267 	int ret;
268 
269 	exynos_gem_obj = exynos_drm_gem_create(dev, args->flags, args->size);
270 	if (IS_ERR(exynos_gem_obj))
271 		return PTR_ERR(exynos_gem_obj);
272 
273 	ret = exynos_drm_gem_handle_create(&exynos_gem_obj->base, file_priv,
274 			&args->handle);
275 	if (ret) {
276 		exynos_drm_gem_destroy(exynos_gem_obj);
277 		return ret;
278 	}
279 
280 	return 0;
281 }
282 
283 dma_addr_t *exynos_drm_gem_get_dma_addr(struct drm_device *dev,
284 					unsigned int gem_handle,
285 					struct drm_file *filp)
286 {
287 	struct exynos_drm_gem_obj *exynos_gem_obj;
288 	struct drm_gem_object *obj;
289 
290 	obj = drm_gem_object_lookup(dev, filp, gem_handle);
291 	if (!obj) {
292 		DRM_ERROR("failed to lookup gem object.\n");
293 		return ERR_PTR(-EINVAL);
294 	}
295 
296 	exynos_gem_obj = to_exynos_gem_obj(obj);
297 
298 	return &exynos_gem_obj->buffer->dma_addr;
299 }
300 
301 void exynos_drm_gem_put_dma_addr(struct drm_device *dev,
302 					unsigned int gem_handle,
303 					struct drm_file *filp)
304 {
305 	struct exynos_drm_gem_obj *exynos_gem_obj;
306 	struct drm_gem_object *obj;
307 
308 	obj = drm_gem_object_lookup(dev, filp, gem_handle);
309 	if (!obj) {
310 		DRM_ERROR("failed to lookup gem object.\n");
311 		return;
312 	}
313 
314 	exynos_gem_obj = to_exynos_gem_obj(obj);
315 
316 	drm_gem_object_unreference_unlocked(obj);
317 
318 	/*
319 	 * decrease obj->refcount one more time because we has already
320 	 * increased it at exynos_drm_gem_get_dma_addr().
321 	 */
322 	drm_gem_object_unreference_unlocked(obj);
323 }
324 
325 int exynos_drm_gem_map_offset_ioctl(struct drm_device *dev, void *data,
326 				    struct drm_file *file_priv)
327 {
328 	struct drm_exynos_gem_map_off *args = data;
329 
330 	DRM_DEBUG_KMS("handle = 0x%x, offset = 0x%lx\n",
331 			args->handle, (unsigned long)args->offset);
332 
333 	if (!(dev->driver->driver_features & DRIVER_GEM)) {
334 		DRM_ERROR("does not support GEM.\n");
335 		return -ENODEV;
336 	}
337 
338 	return exynos_drm_gem_dumb_map_offset(file_priv, dev, args->handle,
339 			&args->offset);
340 }
341 
342 static struct drm_file *exynos_drm_find_drm_file(struct drm_device *drm_dev,
343 							struct file *filp)
344 {
345 	struct drm_file *file_priv;
346 
347 	/* find current process's drm_file from filelist. */
348 	list_for_each_entry(file_priv, &drm_dev->filelist, lhead)
349 		if (file_priv->filp == filp)
350 			return file_priv;
351 
352 	WARN_ON(1);
353 
354 	return ERR_PTR(-EFAULT);
355 }
356 
357 static int exynos_drm_gem_mmap_buffer(struct file *filp,
358 				      struct vm_area_struct *vma)
359 {
360 	struct drm_gem_object *obj = filp->private_data;
361 	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
362 	struct drm_device *drm_dev = obj->dev;
363 	struct exynos_drm_gem_buf *buffer;
364 	struct drm_file *file_priv;
365 	unsigned long vm_size;
366 	int ret;
367 
368 	vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
369 	vma->vm_private_data = obj;
370 	vma->vm_ops = drm_dev->driver->gem_vm_ops;
371 
372 	/* restore it to driver's fops. */
373 	filp->f_op = fops_get(drm_dev->driver->fops);
374 
375 	file_priv = exynos_drm_find_drm_file(drm_dev, filp);
376 	if (IS_ERR(file_priv))
377 		return PTR_ERR(file_priv);
378 
379 	/* restore it to drm_file. */
380 	filp->private_data = file_priv;
381 
382 	update_vm_cache_attr(exynos_gem_obj, vma);
383 
384 	vm_size = vma->vm_end - vma->vm_start;
385 
386 	/*
387 	 * a buffer contains information to physically continuous memory
388 	 * allocated by user request or at framebuffer creation.
389 	 */
390 	buffer = exynos_gem_obj->buffer;
391 
392 	/* check if user-requested size is valid. */
393 	if (vm_size > buffer->size)
394 		return -EINVAL;
395 
396 	ret = dma_mmap_attrs(drm_dev->dev, vma, buffer->pages,
397 				buffer->dma_addr, buffer->size,
398 				&buffer->dma_attrs);
399 	if (ret < 0) {
400 		DRM_ERROR("failed to mmap.\n");
401 		return ret;
402 	}
403 
404 	/*
405 	 * take a reference to this mapping of the object. And this reference
406 	 * is unreferenced by the corresponding vm_close call.
407 	 */
408 	drm_gem_object_reference(obj);
409 
410 	drm_vm_open_locked(drm_dev, vma);
411 
412 	return 0;
413 }
414 
415 static const struct file_operations exynos_drm_gem_fops = {
416 	.mmap = exynos_drm_gem_mmap_buffer,
417 };
418 
419 int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, void *data,
420 			      struct drm_file *file_priv)
421 {
422 	struct drm_exynos_gem_mmap *args = data;
423 	struct drm_gem_object *obj;
424 	unsigned long addr;
425 
426 	if (!(dev->driver->driver_features & DRIVER_GEM)) {
427 		DRM_ERROR("does not support GEM.\n");
428 		return -ENODEV;
429 	}
430 
431 	obj = drm_gem_object_lookup(dev, file_priv, args->handle);
432 	if (!obj) {
433 		DRM_ERROR("failed to lookup gem object.\n");
434 		return -EINVAL;
435 	}
436 
437 	/*
438 	 * We have to use gem object and its fops for specific mmaper,
439 	 * but vm_mmap() can deliver only filp. So we have to change
440 	 * filp->f_op and filp->private_data temporarily, then restore
441 	 * again. So it is important to keep lock until restoration the
442 	 * settings to prevent others from misuse of filp->f_op or
443 	 * filp->private_data.
444 	 */
445 	mutex_lock(&dev->struct_mutex);
446 
447 	/*
448 	 * Set specific mmper's fops. And it will be restored by
449 	 * exynos_drm_gem_mmap_buffer to dev->driver->fops.
450 	 * This is used to call specific mapper temporarily.
451 	 */
452 	file_priv->filp->f_op = &exynos_drm_gem_fops;
453 
454 	/*
455 	 * Set gem object to private_data so that specific mmaper
456 	 * can get the gem object. And it will be restored by
457 	 * exynos_drm_gem_mmap_buffer to drm_file.
458 	 */
459 	file_priv->filp->private_data = obj;
460 
461 	addr = vm_mmap(file_priv->filp, 0, args->size,
462 			PROT_READ | PROT_WRITE, MAP_SHARED, 0);
463 
464 	drm_gem_object_unreference(obj);
465 
466 	if (IS_ERR_VALUE(addr)) {
467 		/* check filp->f_op, filp->private_data are restored */
468 		if (file_priv->filp->f_op == &exynos_drm_gem_fops) {
469 			file_priv->filp->f_op = fops_get(dev->driver->fops);
470 			file_priv->filp->private_data = file_priv;
471 		}
472 		mutex_unlock(&dev->struct_mutex);
473 		return (int)addr;
474 	}
475 
476 	mutex_unlock(&dev->struct_mutex);
477 
478 	args->mapped = addr;
479 
480 	DRM_DEBUG_KMS("mapped = 0x%lx\n", (unsigned long)args->mapped);
481 
482 	return 0;
483 }
484 
485 int exynos_drm_gem_get_ioctl(struct drm_device *dev, void *data,
486 				      struct drm_file *file_priv)
487 {	struct exynos_drm_gem_obj *exynos_gem_obj;
488 	struct drm_exynos_gem_info *args = data;
489 	struct drm_gem_object *obj;
490 
491 	mutex_lock(&dev->struct_mutex);
492 
493 	obj = drm_gem_object_lookup(dev, file_priv, args->handle);
494 	if (!obj) {
495 		DRM_ERROR("failed to lookup gem object.\n");
496 		mutex_unlock(&dev->struct_mutex);
497 		return -EINVAL;
498 	}
499 
500 	exynos_gem_obj = to_exynos_gem_obj(obj);
501 
502 	args->flags = exynos_gem_obj->flags;
503 	args->size = exynos_gem_obj->size;
504 
505 	drm_gem_object_unreference(obj);
506 	mutex_unlock(&dev->struct_mutex);
507 
508 	return 0;
509 }
510 
511 struct vm_area_struct *exynos_gem_get_vma(struct vm_area_struct *vma)
512 {
513 	struct vm_area_struct *vma_copy;
514 
515 	vma_copy = kmalloc(sizeof(*vma_copy), GFP_KERNEL);
516 	if (!vma_copy)
517 		return NULL;
518 
519 	if (vma->vm_ops && vma->vm_ops->open)
520 		vma->vm_ops->open(vma);
521 
522 	if (vma->vm_file)
523 		get_file(vma->vm_file);
524 
525 	memcpy(vma_copy, vma, sizeof(*vma));
526 
527 	vma_copy->vm_mm = NULL;
528 	vma_copy->vm_next = NULL;
529 	vma_copy->vm_prev = NULL;
530 
531 	return vma_copy;
532 }
533 
534 void exynos_gem_put_vma(struct vm_area_struct *vma)
535 {
536 	if (!vma)
537 		return;
538 
539 	if (vma->vm_ops && vma->vm_ops->close)
540 		vma->vm_ops->close(vma);
541 
542 	if (vma->vm_file)
543 		fput(vma->vm_file);
544 
545 	kfree(vma);
546 }
547 
548 int exynos_gem_get_pages_from_userptr(unsigned long start,
549 						unsigned int npages,
550 						struct page **pages,
551 						struct vm_area_struct *vma)
552 {
553 	int get_npages;
554 
555 	/* the memory region mmaped with VM_PFNMAP. */
556 	if (vma_is_io(vma)) {
557 		unsigned int i;
558 
559 		for (i = 0; i < npages; ++i, start += PAGE_SIZE) {
560 			unsigned long pfn;
561 			int ret = follow_pfn(vma, start, &pfn);
562 			if (ret)
563 				return ret;
564 
565 			pages[i] = pfn_to_page(pfn);
566 		}
567 
568 		if (i != npages) {
569 			DRM_ERROR("failed to get user_pages.\n");
570 			return -EINVAL;
571 		}
572 
573 		return 0;
574 	}
575 
576 	get_npages = get_user_pages(current, current->mm, start,
577 					npages, 1, 1, pages, NULL);
578 	get_npages = max(get_npages, 0);
579 	if (get_npages != npages) {
580 		DRM_ERROR("failed to get user_pages.\n");
581 		while (get_npages)
582 			put_page(pages[--get_npages]);
583 		return -EFAULT;
584 	}
585 
586 	return 0;
587 }
588 
589 void exynos_gem_put_pages_to_userptr(struct page **pages,
590 					unsigned int npages,
591 					struct vm_area_struct *vma)
592 {
593 	if (!vma_is_io(vma)) {
594 		unsigned int i;
595 
596 		for (i = 0; i < npages; i++) {
597 			set_page_dirty_lock(pages[i]);
598 
599 			/*
600 			 * undo the reference we took when populating
601 			 * the table.
602 			 */
603 			put_page(pages[i]);
604 		}
605 	}
606 }
607 
608 int exynos_gem_map_sgt_with_dma(struct drm_device *drm_dev,
609 				struct sg_table *sgt,
610 				enum dma_data_direction dir)
611 {
612 	int nents;
613 
614 	mutex_lock(&drm_dev->struct_mutex);
615 
616 	nents = dma_map_sg(drm_dev->dev, sgt->sgl, sgt->nents, dir);
617 	if (!nents) {
618 		DRM_ERROR("failed to map sgl with dma.\n");
619 		mutex_unlock(&drm_dev->struct_mutex);
620 		return nents;
621 	}
622 
623 	mutex_unlock(&drm_dev->struct_mutex);
624 	return 0;
625 }
626 
627 void exynos_gem_unmap_sgt_from_dma(struct drm_device *drm_dev,
628 				struct sg_table *sgt,
629 				enum dma_data_direction dir)
630 {
631 	dma_unmap_sg(drm_dev->dev, sgt->sgl, sgt->nents, dir);
632 }
633 
634 int exynos_drm_gem_init_object(struct drm_gem_object *obj)
635 {
636 	return 0;
637 }
638 
639 void exynos_drm_gem_free_object(struct drm_gem_object *obj)
640 {
641 	struct exynos_drm_gem_obj *exynos_gem_obj;
642 	struct exynos_drm_gem_buf *buf;
643 
644 	exynos_gem_obj = to_exynos_gem_obj(obj);
645 	buf = exynos_gem_obj->buffer;
646 
647 	if (obj->import_attach)
648 		drm_prime_gem_destroy(obj, buf->sgt);
649 
650 	exynos_drm_gem_destroy(to_exynos_gem_obj(obj));
651 }
652 
653 int exynos_drm_gem_dumb_create(struct drm_file *file_priv,
654 			       struct drm_device *dev,
655 			       struct drm_mode_create_dumb *args)
656 {
657 	struct exynos_drm_gem_obj *exynos_gem_obj;
658 	int ret;
659 
660 	/*
661 	 * alocate memory to be used for framebuffer.
662 	 * - this callback would be called by user application
663 	 *	with DRM_IOCTL_MODE_CREATE_DUMB command.
664 	 */
665 
666 	args->pitch = args->width * ((args->bpp + 7) / 8);
667 	args->size = args->pitch * args->height;
668 
669 	exynos_gem_obj = exynos_drm_gem_create(dev, EXYNOS_BO_CONTIG |
670 						EXYNOS_BO_WC, args->size);
671 	if (IS_ERR(exynos_gem_obj))
672 		return PTR_ERR(exynos_gem_obj);
673 
674 	ret = exynos_drm_gem_handle_create(&exynos_gem_obj->base, file_priv,
675 			&args->handle);
676 	if (ret) {
677 		exynos_drm_gem_destroy(exynos_gem_obj);
678 		return ret;
679 	}
680 
681 	return 0;
682 }
683 
684 int exynos_drm_gem_dumb_map_offset(struct drm_file *file_priv,
685 				   struct drm_device *dev, uint32_t handle,
686 				   uint64_t *offset)
687 {
688 	struct drm_gem_object *obj;
689 	int ret = 0;
690 
691 	mutex_lock(&dev->struct_mutex);
692 
693 	/*
694 	 * get offset of memory allocated for drm framebuffer.
695 	 * - this callback would be called by user application
696 	 *	with DRM_IOCTL_MODE_MAP_DUMB command.
697 	 */
698 
699 	obj = drm_gem_object_lookup(dev, file_priv, handle);
700 	if (!obj) {
701 		DRM_ERROR("failed to lookup gem object.\n");
702 		ret = -EINVAL;
703 		goto unlock;
704 	}
705 
706 	if (!obj->map_list.map) {
707 		ret = drm_gem_create_mmap_offset(obj);
708 		if (ret)
709 			goto out;
710 	}
711 
712 	*offset = (u64)obj->map_list.hash.key << PAGE_SHIFT;
713 	DRM_DEBUG_KMS("offset = 0x%lx\n", (unsigned long)*offset);
714 
715 out:
716 	drm_gem_object_unreference(obj);
717 unlock:
718 	mutex_unlock(&dev->struct_mutex);
719 	return ret;
720 }
721 
722 int exynos_drm_gem_dumb_destroy(struct drm_file *file_priv,
723 				struct drm_device *dev,
724 				unsigned int handle)
725 {
726 	int ret;
727 
728 	/*
729 	 * obj->refcount and obj->handle_count are decreased and
730 	 * if both them are 0 then exynos_drm_gem_free_object()
731 	 * would be called by callback to release resources.
732 	 */
733 	ret = drm_gem_handle_delete(file_priv, handle);
734 	if (ret < 0) {
735 		DRM_ERROR("failed to delete drm_gem_handle.\n");
736 		return ret;
737 	}
738 
739 	return 0;
740 }
741 
742 int exynos_drm_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
743 {
744 	struct drm_gem_object *obj = vma->vm_private_data;
745 	struct drm_device *dev = obj->dev;
746 	unsigned long f_vaddr;
747 	pgoff_t page_offset;
748 	int ret;
749 
750 	page_offset = ((unsigned long)vmf->virtual_address -
751 			vma->vm_start) >> PAGE_SHIFT;
752 	f_vaddr = (unsigned long)vmf->virtual_address;
753 
754 	mutex_lock(&dev->struct_mutex);
755 
756 	ret = exynos_drm_gem_map_buf(obj, vma, f_vaddr, page_offset);
757 	if (ret < 0)
758 		DRM_ERROR("failed to map a buffer with user.\n");
759 
760 	mutex_unlock(&dev->struct_mutex);
761 
762 	return convert_to_vm_err_msg(ret);
763 }
764 
765 int exynos_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
766 {
767 	struct exynos_drm_gem_obj *exynos_gem_obj;
768 	struct drm_gem_object *obj;
769 	int ret;
770 
771 	/* set vm_area_struct. */
772 	ret = drm_gem_mmap(filp, vma);
773 	if (ret < 0) {
774 		DRM_ERROR("failed to mmap.\n");
775 		return ret;
776 	}
777 
778 	obj = vma->vm_private_data;
779 	exynos_gem_obj = to_exynos_gem_obj(obj);
780 
781 	ret = check_gem_flags(exynos_gem_obj->flags);
782 	if (ret) {
783 		drm_gem_vm_close(vma);
784 		drm_gem_free_mmap_offset(obj);
785 		return ret;
786 	}
787 
788 	vma->vm_flags &= ~VM_PFNMAP;
789 	vma->vm_flags |= VM_MIXEDMAP;
790 
791 	update_vm_cache_attr(exynos_gem_obj, vma);
792 
793 	return ret;
794 }
795