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 	DRM_DEBUG_KMS("%s\n", __FILE__);
136 
137 	obj = &exynos_gem_obj->base;
138 	buf = exynos_gem_obj->buffer;
139 
140 	DRM_DEBUG_KMS("handle count = %d\n", atomic_read(&obj->handle_count));
141 
142 	/*
143 	 * do not release memory region from exporter.
144 	 *
145 	 * the region will be released by exporter
146 	 * once dmabuf's refcount becomes 0.
147 	 */
148 	if (obj->import_attach)
149 		goto out;
150 
151 	exynos_drm_free_buf(obj->dev, exynos_gem_obj->flags, buf);
152 
153 out:
154 	exynos_drm_fini_buf(obj->dev, buf);
155 	exynos_gem_obj->buffer = NULL;
156 
157 	if (obj->map_list.map)
158 		drm_gem_free_mmap_offset(obj);
159 
160 	/* release file pointer to gem object. */
161 	drm_gem_object_release(obj);
162 
163 	kfree(exynos_gem_obj);
164 	exynos_gem_obj = NULL;
165 }
166 
167 struct exynos_drm_gem_obj *exynos_drm_gem_init(struct drm_device *dev,
168 						      unsigned long size)
169 {
170 	struct exynos_drm_gem_obj *exynos_gem_obj;
171 	struct drm_gem_object *obj;
172 	int ret;
173 
174 	exynos_gem_obj = kzalloc(sizeof(*exynos_gem_obj), GFP_KERNEL);
175 	if (!exynos_gem_obj) {
176 		DRM_ERROR("failed to allocate exynos gem object\n");
177 		return NULL;
178 	}
179 
180 	exynos_gem_obj->size = size;
181 	obj = &exynos_gem_obj->base;
182 
183 	ret = drm_gem_object_init(dev, obj, size);
184 	if (ret < 0) {
185 		DRM_ERROR("failed to initialize gem object\n");
186 		kfree(exynos_gem_obj);
187 		return NULL;
188 	}
189 
190 	DRM_DEBUG_KMS("created file object = 0x%x\n", (unsigned int)obj->filp);
191 
192 	return exynos_gem_obj;
193 }
194 
195 struct exynos_drm_gem_obj *exynos_drm_gem_create(struct drm_device *dev,
196 						unsigned int flags,
197 						unsigned long size)
198 {
199 	struct exynos_drm_gem_obj *exynos_gem_obj;
200 	struct exynos_drm_gem_buf *buf;
201 	int ret;
202 
203 	if (!size) {
204 		DRM_ERROR("invalid size.\n");
205 		return ERR_PTR(-EINVAL);
206 	}
207 
208 	size = roundup_gem_size(size, flags);
209 	DRM_DEBUG_KMS("%s\n", __FILE__);
210 
211 	ret = check_gem_flags(flags);
212 	if (ret)
213 		return ERR_PTR(ret);
214 
215 	buf = exynos_drm_init_buf(dev, size);
216 	if (!buf)
217 		return ERR_PTR(-ENOMEM);
218 
219 	exynos_gem_obj = exynos_drm_gem_init(dev, size);
220 	if (!exynos_gem_obj) {
221 		ret = -ENOMEM;
222 		goto err_fini_buf;
223 	}
224 
225 	exynos_gem_obj->buffer = buf;
226 
227 	/* set memory type and cache attribute from user side. */
228 	exynos_gem_obj->flags = flags;
229 
230 	ret = exynos_drm_alloc_buf(dev, buf, flags);
231 	if (ret < 0) {
232 		drm_gem_object_release(&exynos_gem_obj->base);
233 		goto err_fini_buf;
234 	}
235 
236 	return exynos_gem_obj;
237 
238 err_fini_buf:
239 	exynos_drm_fini_buf(dev, buf);
240 	return ERR_PTR(ret);
241 }
242 
243 int exynos_drm_gem_create_ioctl(struct drm_device *dev, void *data,
244 				struct drm_file *file_priv)
245 {
246 	struct drm_exynos_gem_create *args = data;
247 	struct exynos_drm_gem_obj *exynos_gem_obj;
248 	int ret;
249 
250 	DRM_DEBUG_KMS("%s\n", __FILE__);
251 
252 	exynos_gem_obj = exynos_drm_gem_create(dev, args->flags, args->size);
253 	if (IS_ERR(exynos_gem_obj))
254 		return PTR_ERR(exynos_gem_obj);
255 
256 	ret = exynos_drm_gem_handle_create(&exynos_gem_obj->base, file_priv,
257 			&args->handle);
258 	if (ret) {
259 		exynos_drm_gem_destroy(exynos_gem_obj);
260 		return ret;
261 	}
262 
263 	return 0;
264 }
265 
266 dma_addr_t *exynos_drm_gem_get_dma_addr(struct drm_device *dev,
267 					unsigned int gem_handle,
268 					struct drm_file *filp)
269 {
270 	struct exynos_drm_gem_obj *exynos_gem_obj;
271 	struct drm_gem_object *obj;
272 
273 	obj = drm_gem_object_lookup(dev, filp, gem_handle);
274 	if (!obj) {
275 		DRM_ERROR("failed to lookup gem object.\n");
276 		return ERR_PTR(-EINVAL);
277 	}
278 
279 	exynos_gem_obj = to_exynos_gem_obj(obj);
280 
281 	return &exynos_gem_obj->buffer->dma_addr;
282 }
283 
284 void exynos_drm_gem_put_dma_addr(struct drm_device *dev,
285 					unsigned int gem_handle,
286 					struct drm_file *filp)
287 {
288 	struct exynos_drm_gem_obj *exynos_gem_obj;
289 	struct drm_gem_object *obj;
290 
291 	obj = drm_gem_object_lookup(dev, filp, gem_handle);
292 	if (!obj) {
293 		DRM_ERROR("failed to lookup gem object.\n");
294 		return;
295 	}
296 
297 	exynos_gem_obj = to_exynos_gem_obj(obj);
298 
299 	drm_gem_object_unreference_unlocked(obj);
300 
301 	/*
302 	 * decrease obj->refcount one more time because we has already
303 	 * increased it at exynos_drm_gem_get_dma_addr().
304 	 */
305 	drm_gem_object_unreference_unlocked(obj);
306 }
307 
308 int exynos_drm_gem_map_offset_ioctl(struct drm_device *dev, void *data,
309 				    struct drm_file *file_priv)
310 {
311 	struct drm_exynos_gem_map_off *args = data;
312 
313 	DRM_DEBUG_KMS("%s\n", __FILE__);
314 
315 	DRM_DEBUG_KMS("handle = 0x%x, offset = 0x%lx\n",
316 			args->handle, (unsigned long)args->offset);
317 
318 	if (!(dev->driver->driver_features & DRIVER_GEM)) {
319 		DRM_ERROR("does not support GEM.\n");
320 		return -ENODEV;
321 	}
322 
323 	return exynos_drm_gem_dumb_map_offset(file_priv, dev, args->handle,
324 			&args->offset);
325 }
326 
327 static struct drm_file *exynos_drm_find_drm_file(struct drm_device *drm_dev,
328 							struct file *filp)
329 {
330 	struct drm_file *file_priv;
331 
332 	/* find current process's drm_file from filelist. */
333 	list_for_each_entry(file_priv, &drm_dev->filelist, lhead)
334 		if (file_priv->filp == filp)
335 			return file_priv;
336 
337 	WARN_ON(1);
338 
339 	return ERR_PTR(-EFAULT);
340 }
341 
342 static int exynos_drm_gem_mmap_buffer(struct file *filp,
343 				      struct vm_area_struct *vma)
344 {
345 	struct drm_gem_object *obj = filp->private_data;
346 	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
347 	struct drm_device *drm_dev = obj->dev;
348 	struct exynos_drm_gem_buf *buffer;
349 	struct drm_file *file_priv;
350 	unsigned long vm_size;
351 	int ret;
352 
353 	DRM_DEBUG_KMS("%s\n", __FILE__);
354 
355 	vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
356 	vma->vm_private_data = obj;
357 	vma->vm_ops = drm_dev->driver->gem_vm_ops;
358 
359 	/* restore it to driver's fops. */
360 	filp->f_op = fops_get(drm_dev->driver->fops);
361 
362 	file_priv = exynos_drm_find_drm_file(drm_dev, filp);
363 	if (IS_ERR(file_priv))
364 		return PTR_ERR(file_priv);
365 
366 	/* restore it to drm_file. */
367 	filp->private_data = file_priv;
368 
369 	update_vm_cache_attr(exynos_gem_obj, vma);
370 
371 	vm_size = vma->vm_end - vma->vm_start;
372 
373 	/*
374 	 * a buffer contains information to physically continuous memory
375 	 * allocated by user request or at framebuffer creation.
376 	 */
377 	buffer = exynos_gem_obj->buffer;
378 
379 	/* check if user-requested size is valid. */
380 	if (vm_size > buffer->size)
381 		return -EINVAL;
382 
383 	ret = dma_mmap_attrs(drm_dev->dev, vma, buffer->pages,
384 				buffer->dma_addr, buffer->size,
385 				&buffer->dma_attrs);
386 	if (ret < 0) {
387 		DRM_ERROR("failed to mmap.\n");
388 		return ret;
389 	}
390 
391 	/*
392 	 * take a reference to this mapping of the object. And this reference
393 	 * is unreferenced by the corresponding vm_close call.
394 	 */
395 	drm_gem_object_reference(obj);
396 
397 	drm_vm_open_locked(drm_dev, vma);
398 
399 	return 0;
400 }
401 
402 static const struct file_operations exynos_drm_gem_fops = {
403 	.mmap = exynos_drm_gem_mmap_buffer,
404 };
405 
406 int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, void *data,
407 			      struct drm_file *file_priv)
408 {
409 	struct drm_exynos_gem_mmap *args = data;
410 	struct drm_gem_object *obj;
411 	unsigned int addr;
412 
413 	DRM_DEBUG_KMS("%s\n", __FILE__);
414 
415 	if (!(dev->driver->driver_features & DRIVER_GEM)) {
416 		DRM_ERROR("does not support GEM.\n");
417 		return -ENODEV;
418 	}
419 
420 	obj = drm_gem_object_lookup(dev, file_priv, args->handle);
421 	if (!obj) {
422 		DRM_ERROR("failed to lookup gem object.\n");
423 		return -EINVAL;
424 	}
425 
426 	/*
427 	 * We have to use gem object and its fops for specific mmaper,
428 	 * but vm_mmap() can deliver only filp. So we have to change
429 	 * filp->f_op and filp->private_data temporarily, then restore
430 	 * again. So it is important to keep lock until restoration the
431 	 * settings to prevent others from misuse of filp->f_op or
432 	 * filp->private_data.
433 	 */
434 	mutex_lock(&dev->struct_mutex);
435 
436 	/*
437 	 * Set specific mmper's fops. And it will be restored by
438 	 * exynos_drm_gem_mmap_buffer to dev->driver->fops.
439 	 * This is used to call specific mapper temporarily.
440 	 */
441 	file_priv->filp->f_op = &exynos_drm_gem_fops;
442 
443 	/*
444 	 * Set gem object to private_data so that specific mmaper
445 	 * can get the gem object. And it will be restored by
446 	 * exynos_drm_gem_mmap_buffer to drm_file.
447 	 */
448 	file_priv->filp->private_data = obj;
449 
450 	addr = vm_mmap(file_priv->filp, 0, args->size,
451 			PROT_READ | PROT_WRITE, MAP_SHARED, 0);
452 
453 	drm_gem_object_unreference(obj);
454 
455 	if (IS_ERR((void *)addr)) {
456 		/* check filp->f_op, filp->private_data are restored */
457 		if (file_priv->filp->f_op == &exynos_drm_gem_fops) {
458 			file_priv->filp->f_op = fops_get(dev->driver->fops);
459 			file_priv->filp->private_data = file_priv;
460 		}
461 		mutex_unlock(&dev->struct_mutex);
462 		return PTR_ERR((void *)addr);
463 	}
464 
465 	mutex_unlock(&dev->struct_mutex);
466 
467 	args->mapped = addr;
468 
469 	DRM_DEBUG_KMS("mapped = 0x%lx\n", (unsigned long)args->mapped);
470 
471 	return 0;
472 }
473 
474 int exynos_drm_gem_get_ioctl(struct drm_device *dev, void *data,
475 				      struct drm_file *file_priv)
476 {	struct exynos_drm_gem_obj *exynos_gem_obj;
477 	struct drm_exynos_gem_info *args = data;
478 	struct drm_gem_object *obj;
479 
480 	mutex_lock(&dev->struct_mutex);
481 
482 	obj = drm_gem_object_lookup(dev, file_priv, args->handle);
483 	if (!obj) {
484 		DRM_ERROR("failed to lookup gem object.\n");
485 		mutex_unlock(&dev->struct_mutex);
486 		return -EINVAL;
487 	}
488 
489 	exynos_gem_obj = to_exynos_gem_obj(obj);
490 
491 	args->flags = exynos_gem_obj->flags;
492 	args->size = exynos_gem_obj->size;
493 
494 	drm_gem_object_unreference(obj);
495 	mutex_unlock(&dev->struct_mutex);
496 
497 	return 0;
498 }
499 
500 struct vm_area_struct *exynos_gem_get_vma(struct vm_area_struct *vma)
501 {
502 	struct vm_area_struct *vma_copy;
503 
504 	vma_copy = kmalloc(sizeof(*vma_copy), GFP_KERNEL);
505 	if (!vma_copy)
506 		return NULL;
507 
508 	if (vma->vm_ops && vma->vm_ops->open)
509 		vma->vm_ops->open(vma);
510 
511 	if (vma->vm_file)
512 		get_file(vma->vm_file);
513 
514 	memcpy(vma_copy, vma, sizeof(*vma));
515 
516 	vma_copy->vm_mm = NULL;
517 	vma_copy->vm_next = NULL;
518 	vma_copy->vm_prev = NULL;
519 
520 	return vma_copy;
521 }
522 
523 void exynos_gem_put_vma(struct vm_area_struct *vma)
524 {
525 	if (!vma)
526 		return;
527 
528 	if (vma->vm_ops && vma->vm_ops->close)
529 		vma->vm_ops->close(vma);
530 
531 	if (vma->vm_file)
532 		fput(vma->vm_file);
533 
534 	kfree(vma);
535 }
536 
537 int exynos_gem_get_pages_from_userptr(unsigned long start,
538 						unsigned int npages,
539 						struct page **pages,
540 						struct vm_area_struct *vma)
541 {
542 	int get_npages;
543 
544 	/* the memory region mmaped with VM_PFNMAP. */
545 	if (vma_is_io(vma)) {
546 		unsigned int i;
547 
548 		for (i = 0; i < npages; ++i, start += PAGE_SIZE) {
549 			unsigned long pfn;
550 			int ret = follow_pfn(vma, start, &pfn);
551 			if (ret)
552 				return ret;
553 
554 			pages[i] = pfn_to_page(pfn);
555 		}
556 
557 		if (i != npages) {
558 			DRM_ERROR("failed to get user_pages.\n");
559 			return -EINVAL;
560 		}
561 
562 		return 0;
563 	}
564 
565 	get_npages = get_user_pages(current, current->mm, start,
566 					npages, 1, 1, pages, NULL);
567 	get_npages = max(get_npages, 0);
568 	if (get_npages != npages) {
569 		DRM_ERROR("failed to get user_pages.\n");
570 		while (get_npages)
571 			put_page(pages[--get_npages]);
572 		return -EFAULT;
573 	}
574 
575 	return 0;
576 }
577 
578 void exynos_gem_put_pages_to_userptr(struct page **pages,
579 					unsigned int npages,
580 					struct vm_area_struct *vma)
581 {
582 	if (!vma_is_io(vma)) {
583 		unsigned int i;
584 
585 		for (i = 0; i < npages; i++) {
586 			set_page_dirty_lock(pages[i]);
587 
588 			/*
589 			 * undo the reference we took when populating
590 			 * the table.
591 			 */
592 			put_page(pages[i]);
593 		}
594 	}
595 }
596 
597 int exynos_gem_map_sgt_with_dma(struct drm_device *drm_dev,
598 				struct sg_table *sgt,
599 				enum dma_data_direction dir)
600 {
601 	int nents;
602 
603 	mutex_lock(&drm_dev->struct_mutex);
604 
605 	nents = dma_map_sg(drm_dev->dev, sgt->sgl, sgt->nents, dir);
606 	if (!nents) {
607 		DRM_ERROR("failed to map sgl with dma.\n");
608 		mutex_unlock(&drm_dev->struct_mutex);
609 		return nents;
610 	}
611 
612 	mutex_unlock(&drm_dev->struct_mutex);
613 	return 0;
614 }
615 
616 void exynos_gem_unmap_sgt_from_dma(struct drm_device *drm_dev,
617 				struct sg_table *sgt,
618 				enum dma_data_direction dir)
619 {
620 	dma_unmap_sg(drm_dev->dev, sgt->sgl, sgt->nents, dir);
621 }
622 
623 int exynos_drm_gem_init_object(struct drm_gem_object *obj)
624 {
625 	DRM_DEBUG_KMS("%s\n", __FILE__);
626 
627 	return 0;
628 }
629 
630 void exynos_drm_gem_free_object(struct drm_gem_object *obj)
631 {
632 	struct exynos_drm_gem_obj *exynos_gem_obj;
633 	struct exynos_drm_gem_buf *buf;
634 
635 	DRM_DEBUG_KMS("%s\n", __FILE__);
636 
637 	exynos_gem_obj = to_exynos_gem_obj(obj);
638 	buf = exynos_gem_obj->buffer;
639 
640 	if (obj->import_attach)
641 		drm_prime_gem_destroy(obj, buf->sgt);
642 
643 	exynos_drm_gem_destroy(to_exynos_gem_obj(obj));
644 }
645 
646 int exynos_drm_gem_dumb_create(struct drm_file *file_priv,
647 			       struct drm_device *dev,
648 			       struct drm_mode_create_dumb *args)
649 {
650 	struct exynos_drm_gem_obj *exynos_gem_obj;
651 	int ret;
652 
653 	DRM_DEBUG_KMS("%s\n", __FILE__);
654 
655 	/*
656 	 * alocate memory to be used for framebuffer.
657 	 * - this callback would be called by user application
658 	 *	with DRM_IOCTL_MODE_CREATE_DUMB command.
659 	 */
660 
661 	args->pitch = args->width * ((args->bpp + 7) / 8);
662 	args->size = args->pitch * args->height;
663 
664 	exynos_gem_obj = exynos_drm_gem_create(dev, args->flags, args->size);
665 	if (IS_ERR(exynos_gem_obj))
666 		return PTR_ERR(exynos_gem_obj);
667 
668 	ret = exynos_drm_gem_handle_create(&exynos_gem_obj->base, file_priv,
669 			&args->handle);
670 	if (ret) {
671 		exynos_drm_gem_destroy(exynos_gem_obj);
672 		return ret;
673 	}
674 
675 	return 0;
676 }
677 
678 int exynos_drm_gem_dumb_map_offset(struct drm_file *file_priv,
679 				   struct drm_device *dev, uint32_t handle,
680 				   uint64_t *offset)
681 {
682 	struct drm_gem_object *obj;
683 	int ret = 0;
684 
685 	DRM_DEBUG_KMS("%s\n", __FILE__);
686 
687 	mutex_lock(&dev->struct_mutex);
688 
689 	/*
690 	 * get offset of memory allocated for drm framebuffer.
691 	 * - this callback would be called by user application
692 	 *	with DRM_IOCTL_MODE_MAP_DUMB command.
693 	 */
694 
695 	obj = drm_gem_object_lookup(dev, file_priv, handle);
696 	if (!obj) {
697 		DRM_ERROR("failed to lookup gem object.\n");
698 		ret = -EINVAL;
699 		goto unlock;
700 	}
701 
702 	if (!obj->map_list.map) {
703 		ret = drm_gem_create_mmap_offset(obj);
704 		if (ret)
705 			goto out;
706 	}
707 
708 	*offset = (u64)obj->map_list.hash.key << PAGE_SHIFT;
709 	DRM_DEBUG_KMS("offset = 0x%lx\n", (unsigned long)*offset);
710 
711 out:
712 	drm_gem_object_unreference(obj);
713 unlock:
714 	mutex_unlock(&dev->struct_mutex);
715 	return ret;
716 }
717 
718 int exynos_drm_gem_dumb_destroy(struct drm_file *file_priv,
719 				struct drm_device *dev,
720 				unsigned int handle)
721 {
722 	int ret;
723 
724 	DRM_DEBUG_KMS("%s\n", __FILE__);
725 
726 	/*
727 	 * obj->refcount and obj->handle_count are decreased and
728 	 * if both them are 0 then exynos_drm_gem_free_object()
729 	 * would be called by callback to release resources.
730 	 */
731 	ret = drm_gem_handle_delete(file_priv, handle);
732 	if (ret < 0) {
733 		DRM_ERROR("failed to delete drm_gem_handle.\n");
734 		return ret;
735 	}
736 
737 	return 0;
738 }
739 
740 int exynos_drm_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
741 {
742 	struct drm_gem_object *obj = vma->vm_private_data;
743 	struct drm_device *dev = obj->dev;
744 	unsigned long f_vaddr;
745 	pgoff_t page_offset;
746 	int ret;
747 
748 	page_offset = ((unsigned long)vmf->virtual_address -
749 			vma->vm_start) >> PAGE_SHIFT;
750 	f_vaddr = (unsigned long)vmf->virtual_address;
751 
752 	mutex_lock(&dev->struct_mutex);
753 
754 	ret = exynos_drm_gem_map_buf(obj, vma, f_vaddr, page_offset);
755 	if (ret < 0)
756 		DRM_ERROR("failed to map a buffer with user.\n");
757 
758 	mutex_unlock(&dev->struct_mutex);
759 
760 	return convert_to_vm_err_msg(ret);
761 }
762 
763 int exynos_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
764 {
765 	struct exynos_drm_gem_obj *exynos_gem_obj;
766 	struct drm_gem_object *obj;
767 	int ret;
768 
769 	DRM_DEBUG_KMS("%s\n", __FILE__);
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