1 /* exynos_drm_gem.c
2  *
3  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
4  * Author: Inki Dae <inki.dae@samsung.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the next
14  * paragraph) shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23  * OTHER DEALINGS IN THE SOFTWARE.
24  */
25 
26 #include "drmP.h"
27 #include "drm.h"
28 
29 #include <linux/shmem_fs.h>
30 #include <drm/exynos_drm.h>
31 
32 #include "exynos_drm_drv.h"
33 #include "exynos_drm_gem.h"
34 #include "exynos_drm_buf.h"
35 
36 static unsigned int convert_to_vm_err_msg(int msg)
37 {
38 	unsigned int out_msg;
39 
40 	switch (msg) {
41 	case 0:
42 	case -ERESTARTSYS:
43 	case -EINTR:
44 		out_msg = VM_FAULT_NOPAGE;
45 		break;
46 
47 	case -ENOMEM:
48 		out_msg = VM_FAULT_OOM;
49 		break;
50 
51 	default:
52 		out_msg = VM_FAULT_SIGBUS;
53 		break;
54 	}
55 
56 	return out_msg;
57 }
58 
59 static int check_gem_flags(unsigned int flags)
60 {
61 	if (flags & ~(EXYNOS_BO_MASK)) {
62 		DRM_ERROR("invalid flags.\n");
63 		return -EINVAL;
64 	}
65 
66 	return 0;
67 }
68 
69 static void update_vm_cache_attr(struct exynos_drm_gem_obj *obj,
70 					struct vm_area_struct *vma)
71 {
72 	DRM_DEBUG_KMS("flags = 0x%x\n", obj->flags);
73 
74 	/* non-cachable as default. */
75 	if (obj->flags & EXYNOS_BO_CACHABLE)
76 		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
77 	else if (obj->flags & EXYNOS_BO_WC)
78 		vma->vm_page_prot =
79 			pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
80 	else
81 		vma->vm_page_prot =
82 			pgprot_noncached(vm_get_page_prot(vma->vm_flags));
83 }
84 
85 static unsigned long roundup_gem_size(unsigned long size, unsigned int flags)
86 {
87 	if (!IS_NONCONTIG_BUFFER(flags)) {
88 		if (size >= SZ_1M)
89 			return roundup(size, SECTION_SIZE);
90 		else if (size >= SZ_64K)
91 			return roundup(size, SZ_64K);
92 		else
93 			goto out;
94 	}
95 out:
96 	return roundup(size, PAGE_SIZE);
97 }
98 
99 struct page **exynos_gem_get_pages(struct drm_gem_object *obj,
100 						gfp_t gfpmask)
101 {
102 	struct page *p, **pages;
103 	int i, npages;
104 
105 	npages = obj->size >> PAGE_SHIFT;
106 
107 	pages = drm_malloc_ab(npages, sizeof(struct page *));
108 	if (pages == NULL)
109 		return ERR_PTR(-ENOMEM);
110 
111 	for (i = 0; i < npages; i++) {
112 		p = alloc_page(gfpmask);
113 		if (IS_ERR(p))
114 			goto fail;
115 		pages[i] = p;
116 	}
117 
118 	return pages;
119 
120 fail:
121 	while (--i)
122 		__free_page(pages[i]);
123 
124 	drm_free_large(pages);
125 	return ERR_PTR(PTR_ERR(p));
126 }
127 
128 static void exynos_gem_put_pages(struct drm_gem_object *obj,
129 					struct page **pages)
130 {
131 	int npages;
132 
133 	npages = obj->size >> PAGE_SHIFT;
134 
135 	while (--npages >= 0)
136 		__free_page(pages[npages]);
137 
138 	drm_free_large(pages);
139 }
140 
141 static int exynos_drm_gem_map_pages(struct drm_gem_object *obj,
142 					struct vm_area_struct *vma,
143 					unsigned long f_vaddr,
144 					pgoff_t page_offset)
145 {
146 	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
147 	struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;
148 	unsigned long pfn;
149 
150 	if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) {
151 		if (!buf->pages)
152 			return -EINTR;
153 
154 		pfn = page_to_pfn(buf->pages[page_offset++]);
155 	} else
156 		pfn = (buf->dma_addr >> PAGE_SHIFT) + page_offset;
157 
158 	return vm_insert_mixed(vma, f_vaddr, pfn);
159 }
160 
161 static int exynos_drm_gem_get_pages(struct drm_gem_object *obj)
162 {
163 	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
164 	struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;
165 	struct scatterlist *sgl;
166 	struct page **pages;
167 	unsigned int npages, i = 0;
168 	int ret;
169 
170 	if (buf->pages) {
171 		DRM_DEBUG_KMS("already allocated.\n");
172 		return -EINVAL;
173 	}
174 
175 	pages = exynos_gem_get_pages(obj, GFP_HIGHUSER_MOVABLE);
176 	if (IS_ERR(pages)) {
177 		DRM_ERROR("failed to get pages.\n");
178 		return PTR_ERR(pages);
179 	}
180 
181 	npages = obj->size >> PAGE_SHIFT;
182 	buf->page_size = PAGE_SIZE;
183 
184 	buf->sgt = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
185 	if (!buf->sgt) {
186 		DRM_ERROR("failed to allocate sg table.\n");
187 		ret = -ENOMEM;
188 		goto err;
189 	}
190 
191 	ret = sg_alloc_table(buf->sgt, npages, GFP_KERNEL);
192 	if (ret < 0) {
193 		DRM_ERROR("failed to initialize sg table.\n");
194 		ret = -EFAULT;
195 		goto err1;
196 	}
197 
198 	sgl = buf->sgt->sgl;
199 
200 	/* set all pages to sg list. */
201 	while (i < npages) {
202 		sg_set_page(sgl, pages[i], PAGE_SIZE, 0);
203 		sg_dma_address(sgl) = page_to_phys(pages[i]);
204 		i++;
205 		sgl = sg_next(sgl);
206 	}
207 
208 	/* add some codes for UNCACHED type here. TODO */
209 
210 	buf->pages = pages;
211 	return ret;
212 err1:
213 	kfree(buf->sgt);
214 	buf->sgt = NULL;
215 err:
216 	exynos_gem_put_pages(obj, pages);
217 	return ret;
218 
219 }
220 
221 static void exynos_drm_gem_put_pages(struct drm_gem_object *obj)
222 {
223 	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
224 	struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;
225 
226 	/*
227 	 * if buffer typs is EXYNOS_BO_NONCONTIG then release all pages
228 	 * allocated at gem fault handler.
229 	 */
230 	sg_free_table(buf->sgt);
231 	kfree(buf->sgt);
232 	buf->sgt = NULL;
233 
234 	exynos_gem_put_pages(obj, buf->pages);
235 	buf->pages = NULL;
236 
237 	/* add some codes for UNCACHED type here. TODO */
238 }
239 
240 static int exynos_drm_gem_handle_create(struct drm_gem_object *obj,
241 					struct drm_file *file_priv,
242 					unsigned int *handle)
243 {
244 	int ret;
245 
246 	/*
247 	 * allocate a id of idr table where the obj is registered
248 	 * and handle has the id what user can see.
249 	 */
250 	ret = drm_gem_handle_create(file_priv, obj, handle);
251 	if (ret)
252 		return ret;
253 
254 	DRM_DEBUG_KMS("gem handle = 0x%x\n", *handle);
255 
256 	/* drop reference from allocate - handle holds it now. */
257 	drm_gem_object_unreference_unlocked(obj);
258 
259 	return 0;
260 }
261 
262 void exynos_drm_gem_destroy(struct exynos_drm_gem_obj *exynos_gem_obj)
263 {
264 	struct drm_gem_object *obj;
265 	struct exynos_drm_gem_buf *buf;
266 
267 	DRM_DEBUG_KMS("%s\n", __FILE__);
268 
269 	obj = &exynos_gem_obj->base;
270 	buf = exynos_gem_obj->buffer;
271 
272 	DRM_DEBUG_KMS("handle count = %d\n", atomic_read(&obj->handle_count));
273 
274 	if (!buf->pages)
275 		return;
276 
277 	/*
278 	 * do not release memory region from exporter.
279 	 *
280 	 * the region will be released by exporter
281 	 * once dmabuf's refcount becomes 0.
282 	 */
283 	if (obj->import_attach)
284 		goto out;
285 
286 	if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG)
287 		exynos_drm_gem_put_pages(obj);
288 	else
289 		exynos_drm_free_buf(obj->dev, exynos_gem_obj->flags, buf);
290 
291 out:
292 	exynos_drm_fini_buf(obj->dev, buf);
293 	exynos_gem_obj->buffer = NULL;
294 
295 	if (obj->map_list.map)
296 		drm_gem_free_mmap_offset(obj);
297 
298 	/* release file pointer to gem object. */
299 	drm_gem_object_release(obj);
300 
301 	kfree(exynos_gem_obj);
302 	exynos_gem_obj = NULL;
303 }
304 
305 struct exynos_drm_gem_obj *exynos_drm_gem_init(struct drm_device *dev,
306 						      unsigned long size)
307 {
308 	struct exynos_drm_gem_obj *exynos_gem_obj;
309 	struct drm_gem_object *obj;
310 	int ret;
311 
312 	exynos_gem_obj = kzalloc(sizeof(*exynos_gem_obj), GFP_KERNEL);
313 	if (!exynos_gem_obj) {
314 		DRM_ERROR("failed to allocate exynos gem object\n");
315 		return NULL;
316 	}
317 
318 	exynos_gem_obj->size = size;
319 	obj = &exynos_gem_obj->base;
320 
321 	ret = drm_gem_object_init(dev, obj, size);
322 	if (ret < 0) {
323 		DRM_ERROR("failed to initialize gem object\n");
324 		kfree(exynos_gem_obj);
325 		return NULL;
326 	}
327 
328 	DRM_DEBUG_KMS("created file object = 0x%x\n", (unsigned int)obj->filp);
329 
330 	return exynos_gem_obj;
331 }
332 
333 struct exynos_drm_gem_obj *exynos_drm_gem_create(struct drm_device *dev,
334 						unsigned int flags,
335 						unsigned long size)
336 {
337 	struct exynos_drm_gem_obj *exynos_gem_obj;
338 	struct exynos_drm_gem_buf *buf;
339 	int ret;
340 
341 	if (!size) {
342 		DRM_ERROR("invalid size.\n");
343 		return ERR_PTR(-EINVAL);
344 	}
345 
346 	size = roundup_gem_size(size, flags);
347 	DRM_DEBUG_KMS("%s\n", __FILE__);
348 
349 	ret = check_gem_flags(flags);
350 	if (ret)
351 		return ERR_PTR(ret);
352 
353 	buf = exynos_drm_init_buf(dev, size);
354 	if (!buf)
355 		return ERR_PTR(-ENOMEM);
356 
357 	exynos_gem_obj = exynos_drm_gem_init(dev, size);
358 	if (!exynos_gem_obj) {
359 		ret = -ENOMEM;
360 		goto err_fini_buf;
361 	}
362 
363 	exynos_gem_obj->buffer = buf;
364 
365 	/* set memory type and cache attribute from user side. */
366 	exynos_gem_obj->flags = flags;
367 
368 	/*
369 	 * allocate all pages as desired size if user wants to allocate
370 	 * physically non-continuous memory.
371 	 */
372 	if (flags & EXYNOS_BO_NONCONTIG) {
373 		ret = exynos_drm_gem_get_pages(&exynos_gem_obj->base);
374 		if (ret < 0) {
375 			drm_gem_object_release(&exynos_gem_obj->base);
376 			goto err_fini_buf;
377 		}
378 	} else {
379 		ret = exynos_drm_alloc_buf(dev, buf, flags);
380 		if (ret < 0) {
381 			drm_gem_object_release(&exynos_gem_obj->base);
382 			goto err_fini_buf;
383 		}
384 	}
385 
386 	return exynos_gem_obj;
387 
388 err_fini_buf:
389 	exynos_drm_fini_buf(dev, buf);
390 	return ERR_PTR(ret);
391 }
392 
393 int exynos_drm_gem_create_ioctl(struct drm_device *dev, void *data,
394 				struct drm_file *file_priv)
395 {
396 	struct drm_exynos_gem_create *args = data;
397 	struct exynos_drm_gem_obj *exynos_gem_obj;
398 	int ret;
399 
400 	DRM_DEBUG_KMS("%s\n", __FILE__);
401 
402 	exynos_gem_obj = exynos_drm_gem_create(dev, args->flags, args->size);
403 	if (IS_ERR(exynos_gem_obj))
404 		return PTR_ERR(exynos_gem_obj);
405 
406 	ret = exynos_drm_gem_handle_create(&exynos_gem_obj->base, file_priv,
407 			&args->handle);
408 	if (ret) {
409 		exynos_drm_gem_destroy(exynos_gem_obj);
410 		return ret;
411 	}
412 
413 	return 0;
414 }
415 
416 void *exynos_drm_gem_get_dma_addr(struct drm_device *dev,
417 					unsigned int gem_handle,
418 					struct drm_file *file_priv)
419 {
420 	struct exynos_drm_gem_obj *exynos_gem_obj;
421 	struct drm_gem_object *obj;
422 
423 	obj = drm_gem_object_lookup(dev, file_priv, gem_handle);
424 	if (!obj) {
425 		DRM_ERROR("failed to lookup gem object.\n");
426 		return ERR_PTR(-EINVAL);
427 	}
428 
429 	exynos_gem_obj = to_exynos_gem_obj(obj);
430 
431 	if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) {
432 		DRM_DEBUG_KMS("not support NONCONTIG type.\n");
433 		drm_gem_object_unreference_unlocked(obj);
434 
435 		/* TODO */
436 		return ERR_PTR(-EINVAL);
437 	}
438 
439 	return &exynos_gem_obj->buffer->dma_addr;
440 }
441 
442 void exynos_drm_gem_put_dma_addr(struct drm_device *dev,
443 					unsigned int gem_handle,
444 					struct drm_file *file_priv)
445 {
446 	struct exynos_drm_gem_obj *exynos_gem_obj;
447 	struct drm_gem_object *obj;
448 
449 	obj = drm_gem_object_lookup(dev, file_priv, gem_handle);
450 	if (!obj) {
451 		DRM_ERROR("failed to lookup gem object.\n");
452 		return;
453 	}
454 
455 	exynos_gem_obj = to_exynos_gem_obj(obj);
456 
457 	if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) {
458 		DRM_DEBUG_KMS("not support NONCONTIG type.\n");
459 		drm_gem_object_unreference_unlocked(obj);
460 
461 		/* TODO */
462 		return;
463 	}
464 
465 	drm_gem_object_unreference_unlocked(obj);
466 
467 	/*
468 	 * decrease obj->refcount one more time because we has already
469 	 * increased it at exynos_drm_gem_get_dma_addr().
470 	 */
471 	drm_gem_object_unreference_unlocked(obj);
472 }
473 
474 int exynos_drm_gem_map_offset_ioctl(struct drm_device *dev, void *data,
475 				    struct drm_file *file_priv)
476 {
477 	struct drm_exynos_gem_map_off *args = data;
478 
479 	DRM_DEBUG_KMS("%s\n", __FILE__);
480 
481 	DRM_DEBUG_KMS("handle = 0x%x, offset = 0x%lx\n",
482 			args->handle, (unsigned long)args->offset);
483 
484 	if (!(dev->driver->driver_features & DRIVER_GEM)) {
485 		DRM_ERROR("does not support GEM.\n");
486 		return -ENODEV;
487 	}
488 
489 	return exynos_drm_gem_dumb_map_offset(file_priv, dev, args->handle,
490 			&args->offset);
491 }
492 
493 static int exynos_drm_gem_mmap_buffer(struct file *filp,
494 				      struct vm_area_struct *vma)
495 {
496 	struct drm_gem_object *obj = filp->private_data;
497 	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
498 	struct exynos_drm_gem_buf *buffer;
499 	unsigned long pfn, vm_size, usize, uaddr = vma->vm_start;
500 	int ret;
501 
502 	DRM_DEBUG_KMS("%s\n", __FILE__);
503 
504 	vma->vm_flags |= (VM_IO | VM_RESERVED);
505 
506 	update_vm_cache_attr(exynos_gem_obj, vma);
507 
508 	vm_size = usize = vma->vm_end - vma->vm_start;
509 
510 	/*
511 	 * a buffer contains information to physically continuous memory
512 	 * allocated by user request or at framebuffer creation.
513 	 */
514 	buffer = exynos_gem_obj->buffer;
515 
516 	/* check if user-requested size is valid. */
517 	if (vm_size > buffer->size)
518 		return -EINVAL;
519 
520 	if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) {
521 		int i = 0;
522 
523 		if (!buffer->pages)
524 			return -EINVAL;
525 
526 		vma->vm_flags |= VM_MIXEDMAP;
527 
528 		do {
529 			ret = vm_insert_page(vma, uaddr, buffer->pages[i++]);
530 			if (ret) {
531 				DRM_ERROR("failed to remap user space.\n");
532 				return ret;
533 			}
534 
535 			uaddr += PAGE_SIZE;
536 			usize -= PAGE_SIZE;
537 		} while (usize > 0);
538 	} else {
539 		/*
540 		 * get page frame number to physical memory to be mapped
541 		 * to user space.
542 		 */
543 		pfn = ((unsigned long)exynos_gem_obj->buffer->dma_addr) >>
544 								PAGE_SHIFT;
545 
546 		DRM_DEBUG_KMS("pfn = 0x%lx\n", pfn);
547 
548 		if (remap_pfn_range(vma, vma->vm_start, pfn, vm_size,
549 					vma->vm_page_prot)) {
550 			DRM_ERROR("failed to remap pfn range.\n");
551 			return -EAGAIN;
552 		}
553 	}
554 
555 	return 0;
556 }
557 
558 static const struct file_operations exynos_drm_gem_fops = {
559 	.mmap = exynos_drm_gem_mmap_buffer,
560 };
561 
562 int exynos_drm_gem_mmap_ioctl(struct drm_device *dev, void *data,
563 			      struct drm_file *file_priv)
564 {
565 	struct drm_exynos_gem_mmap *args = data;
566 	struct drm_gem_object *obj;
567 	unsigned int addr;
568 
569 	DRM_DEBUG_KMS("%s\n", __FILE__);
570 
571 	if (!(dev->driver->driver_features & DRIVER_GEM)) {
572 		DRM_ERROR("does not support GEM.\n");
573 		return -ENODEV;
574 	}
575 
576 	obj = drm_gem_object_lookup(dev, file_priv, args->handle);
577 	if (!obj) {
578 		DRM_ERROR("failed to lookup gem object.\n");
579 		return -EINVAL;
580 	}
581 
582 	obj->filp->f_op = &exynos_drm_gem_fops;
583 	obj->filp->private_data = obj;
584 
585 	addr = vm_mmap(obj->filp, 0, args->size,
586 			PROT_READ | PROT_WRITE, MAP_SHARED, 0);
587 
588 	drm_gem_object_unreference_unlocked(obj);
589 
590 	if (IS_ERR((void *)addr))
591 		return PTR_ERR((void *)addr);
592 
593 	args->mapped = addr;
594 
595 	DRM_DEBUG_KMS("mapped = 0x%lx\n", (unsigned long)args->mapped);
596 
597 	return 0;
598 }
599 
600 int exynos_drm_gem_get_ioctl(struct drm_device *dev, void *data,
601 				      struct drm_file *file_priv)
602 {	struct exynos_drm_gem_obj *exynos_gem_obj;
603 	struct drm_exynos_gem_info *args = data;
604 	struct drm_gem_object *obj;
605 
606 	mutex_lock(&dev->struct_mutex);
607 
608 	obj = drm_gem_object_lookup(dev, file_priv, args->handle);
609 	if (!obj) {
610 		DRM_ERROR("failed to lookup gem object.\n");
611 		mutex_unlock(&dev->struct_mutex);
612 		return -EINVAL;
613 	}
614 
615 	exynos_gem_obj = to_exynos_gem_obj(obj);
616 
617 	args->flags = exynos_gem_obj->flags;
618 	args->size = exynos_gem_obj->size;
619 
620 	drm_gem_object_unreference(obj);
621 	mutex_unlock(&dev->struct_mutex);
622 
623 	return 0;
624 }
625 
626 int exynos_drm_gem_init_object(struct drm_gem_object *obj)
627 {
628 	DRM_DEBUG_KMS("%s\n", __FILE__);
629 
630 	return 0;
631 }
632 
633 void exynos_drm_gem_free_object(struct drm_gem_object *obj)
634 {
635 	struct exynos_drm_gem_obj *exynos_gem_obj;
636 	struct exynos_drm_gem_buf *buf;
637 
638 	DRM_DEBUG_KMS("%s\n", __FILE__);
639 
640 	exynos_gem_obj = to_exynos_gem_obj(obj);
641 	buf = exynos_gem_obj->buffer;
642 
643 	if (obj->import_attach)
644 		drm_prime_gem_destroy(obj, buf->sgt);
645 
646 	exynos_drm_gem_destroy(to_exynos_gem_obj(obj));
647 }
648 
649 int exynos_drm_gem_dumb_create(struct drm_file *file_priv,
650 			       struct drm_device *dev,
651 			       struct drm_mode_create_dumb *args)
652 {
653 	struct exynos_drm_gem_obj *exynos_gem_obj;
654 	int ret;
655 
656 	DRM_DEBUG_KMS("%s\n", __FILE__);
657 
658 	/*
659 	 * alocate memory to be used for framebuffer.
660 	 * - this callback would be called by user application
661 	 *	with DRM_IOCTL_MODE_CREATE_DUMB command.
662 	 */
663 
664 	args->pitch = args->width * ((args->bpp + 7) / 8);
665 	args->size = PAGE_ALIGN(args->pitch * args->height);
666 
667 	exynos_gem_obj = exynos_drm_gem_create(dev, args->flags, args->size);
668 	if (IS_ERR(exynos_gem_obj))
669 		return PTR_ERR(exynos_gem_obj);
670 
671 	ret = exynos_drm_gem_handle_create(&exynos_gem_obj->base, file_priv,
672 			&args->handle);
673 	if (ret) {
674 		exynos_drm_gem_destroy(exynos_gem_obj);
675 		return ret;
676 	}
677 
678 	return 0;
679 }
680 
681 int exynos_drm_gem_dumb_map_offset(struct drm_file *file_priv,
682 				   struct drm_device *dev, uint32_t handle,
683 				   uint64_t *offset)
684 {
685 	struct drm_gem_object *obj;
686 	int ret = 0;
687 
688 	DRM_DEBUG_KMS("%s\n", __FILE__);
689 
690 	mutex_lock(&dev->struct_mutex);
691 
692 	/*
693 	 * get offset of memory allocated for drm framebuffer.
694 	 * - this callback would be called by user application
695 	 *	with DRM_IOCTL_MODE_MAP_DUMB command.
696 	 */
697 
698 	obj = drm_gem_object_lookup(dev, file_priv, handle);
699 	if (!obj) {
700 		DRM_ERROR("failed to lookup gem object.\n");
701 		ret = -EINVAL;
702 		goto unlock;
703 	}
704 
705 	if (!obj->map_list.map) {
706 		ret = drm_gem_create_mmap_offset(obj);
707 		if (ret)
708 			goto out;
709 	}
710 
711 	*offset = (u64)obj->map_list.hash.key << PAGE_SHIFT;
712 	DRM_DEBUG_KMS("offset = 0x%lx\n", (unsigned long)*offset);
713 
714 out:
715 	drm_gem_object_unreference(obj);
716 unlock:
717 	mutex_unlock(&dev->struct_mutex);
718 	return ret;
719 }
720 
721 int exynos_drm_gem_dumb_destroy(struct drm_file *file_priv,
722 				struct drm_device *dev,
723 				unsigned int handle)
724 {
725 	int ret;
726 
727 	DRM_DEBUG_KMS("%s\n", __FILE__);
728 
729 	/*
730 	 * obj->refcount and obj->handle_count are decreased and
731 	 * if both them are 0 then exynos_drm_gem_free_object()
732 	 * would be called by callback to release resources.
733 	 */
734 	ret = drm_gem_handle_delete(file_priv, handle);
735 	if (ret < 0) {
736 		DRM_ERROR("failed to delete drm_gem_handle.\n");
737 		return ret;
738 	}
739 
740 	return 0;
741 }
742 
743 int exynos_drm_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
744 {
745 	struct drm_gem_object *obj = vma->vm_private_data;
746 	struct drm_device *dev = obj->dev;
747 	unsigned long f_vaddr;
748 	pgoff_t page_offset;
749 	int ret;
750 
751 	page_offset = ((unsigned long)vmf->virtual_address -
752 			vma->vm_start) >> PAGE_SHIFT;
753 	f_vaddr = (unsigned long)vmf->virtual_address;
754 
755 	mutex_lock(&dev->struct_mutex);
756 
757 	ret = exynos_drm_gem_map_pages(obj, vma, f_vaddr, page_offset);
758 	if (ret < 0)
759 		DRM_ERROR("failed to map pages.\n");
760 
761 	mutex_unlock(&dev->struct_mutex);
762 
763 	return convert_to_vm_err_msg(ret);
764 }
765 
766 int exynos_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
767 {
768 	struct exynos_drm_gem_obj *exynos_gem_obj;
769 	struct drm_gem_object *obj;
770 	int ret;
771 
772 	DRM_DEBUG_KMS("%s\n", __FILE__);
773 
774 	/* set vm_area_struct. */
775 	ret = drm_gem_mmap(filp, vma);
776 	if (ret < 0) {
777 		DRM_ERROR("failed to mmap.\n");
778 		return ret;
779 	}
780 
781 	obj = vma->vm_private_data;
782 	exynos_gem_obj = to_exynos_gem_obj(obj);
783 
784 	ret = check_gem_flags(exynos_gem_obj->flags);
785 	if (ret) {
786 		drm_gem_vm_close(vma);
787 		drm_gem_free_mmap_offset(obj);
788 		return ret;
789 	}
790 
791 	vma->vm_flags &= ~VM_PFNMAP;
792 	vma->vm_flags |= VM_MIXEDMAP;
793 
794 	update_vm_cache_attr(exynos_gem_obj, vma);
795 
796 	return ret;
797 }
798