1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * drm gem CMA (contiguous memory allocator) helper functions
4  *
5  * Copyright (C) 2012 Sascha Hauer, Pengutronix
6  *
7  * Based on Samsung Exynos code
8  *
9  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
10  */
11 
12 #include <linux/dma-buf.h>
13 #include <linux/dma-mapping.h>
14 #include <linux/export.h>
15 #include <linux/mm.h>
16 #include <linux/mutex.h>
17 #include <linux/slab.h>
18 
19 #include <drm/drm.h>
20 #include <drm/drm_device.h>
21 #include <drm/drm_drv.h>
22 #include <drm/drm_gem_cma_helper.h>
23 #include <drm/drm_vma_manager.h>
24 
25 /**
26  * DOC: cma helpers
27  *
28  * The Contiguous Memory Allocator reserves a pool of memory at early boot
29  * that is used to service requests for large blocks of contiguous memory.
30  *
31  * The DRM GEM/CMA helpers use this allocator as a means to provide buffer
32  * objects that are physically contiguous in memory. This is useful for
33  * display drivers that are unable to map scattered buffers via an IOMMU.
34  */
35 
36 /**
37  * __drm_gem_cma_create - Create a GEM CMA object without allocating memory
38  * @drm: DRM device
39  * @size: size of the object to allocate
40  *
41  * This function creates and initializes a GEM CMA object of the given size,
42  * but doesn't allocate any memory to back the object.
43  *
44  * Returns:
45  * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
46  * error code on failure.
47  */
48 static struct drm_gem_cma_object *
__drm_gem_cma_create(struct drm_device * drm,size_t size)49 __drm_gem_cma_create(struct drm_device *drm, size_t size)
50 {
51 	struct drm_gem_cma_object *cma_obj;
52 	struct drm_gem_object *gem_obj;
53 	int ret;
54 
55 	if (drm->driver->gem_create_object)
56 		gem_obj = drm->driver->gem_create_object(drm, size);
57 	else
58 		gem_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
59 	if (!gem_obj)
60 		return ERR_PTR(-ENOMEM);
61 	cma_obj = container_of(gem_obj, struct drm_gem_cma_object, base);
62 
63 	ret = drm_gem_object_init(drm, gem_obj, size);
64 	if (ret)
65 		goto error;
66 
67 	ret = drm_gem_create_mmap_offset(gem_obj);
68 	if (ret) {
69 		drm_gem_object_release(gem_obj);
70 		goto error;
71 	}
72 
73 	return cma_obj;
74 
75 error:
76 	kfree(cma_obj);
77 	return ERR_PTR(ret);
78 }
79 
80 /**
81  * drm_gem_cma_create - allocate an object with the given size
82  * @drm: DRM device
83  * @size: size of the object to allocate
84  *
85  * This function creates a CMA GEM object and allocates a contiguous chunk of
86  * memory as backing store. The backing memory has the writecombine attribute
87  * set.
88  *
89  * Returns:
90  * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
91  * error code on failure.
92  */
drm_gem_cma_create(struct drm_device * drm,size_t size)93 struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
94 					      size_t size)
95 {
96 	struct drm_gem_cma_object *cma_obj;
97 	int ret;
98 
99 	size = round_up(size, PAGE_SIZE);
100 
101 	cma_obj = __drm_gem_cma_create(drm, size);
102 	if (IS_ERR(cma_obj))
103 		return cma_obj;
104 
105 	cma_obj->vaddr = dma_alloc_wc(drm->dev, size, &cma_obj->paddr,
106 				      GFP_KERNEL | __GFP_NOWARN);
107 	if (!cma_obj->vaddr) {
108 		dev_dbg(drm->dev, "failed to allocate buffer with size %zu\n",
109 			size);
110 		ret = -ENOMEM;
111 		goto error;
112 	}
113 
114 	return cma_obj;
115 
116 error:
117 	drm_gem_object_put_unlocked(&cma_obj->base);
118 	return ERR_PTR(ret);
119 }
120 EXPORT_SYMBOL_GPL(drm_gem_cma_create);
121 
122 /**
123  * drm_gem_cma_create_with_handle - allocate an object with the given size and
124  *     return a GEM handle to it
125  * @file_priv: DRM file-private structure to register the handle for
126  * @drm: DRM device
127  * @size: size of the object to allocate
128  * @handle: return location for the GEM handle
129  *
130  * This function creates a CMA GEM object, allocating a physically contiguous
131  * chunk of memory as backing store. The GEM object is then added to the list
132  * of object associated with the given file and a handle to it is returned.
133  *
134  * Returns:
135  * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
136  * error code on failure.
137  */
138 static struct drm_gem_cma_object *
drm_gem_cma_create_with_handle(struct drm_file * file_priv,struct drm_device * drm,size_t size,uint32_t * handle)139 drm_gem_cma_create_with_handle(struct drm_file *file_priv,
140 			       struct drm_device *drm, size_t size,
141 			       uint32_t *handle)
142 {
143 	struct drm_gem_cma_object *cma_obj;
144 	struct drm_gem_object *gem_obj;
145 	int ret;
146 
147 	cma_obj = drm_gem_cma_create(drm, size);
148 	if (IS_ERR(cma_obj))
149 		return cma_obj;
150 
151 	gem_obj = &cma_obj->base;
152 
153 	/*
154 	 * allocate a id of idr table where the obj is registered
155 	 * and handle has the id what user can see.
156 	 */
157 	ret = drm_gem_handle_create(file_priv, gem_obj, handle);
158 	/* drop reference from allocate - handle holds it now. */
159 	drm_gem_object_put_unlocked(gem_obj);
160 	if (ret)
161 		return ERR_PTR(ret);
162 
163 	return cma_obj;
164 }
165 
166 /**
167  * drm_gem_cma_free_object - free resources associated with a CMA GEM object
168  * @gem_obj: GEM object to free
169  *
170  * This function frees the backing memory of the CMA GEM object, cleans up the
171  * GEM object state and frees the memory used to store the object itself.
172  * If the buffer is imported and the virtual address is set, it is released.
173  * Drivers using the CMA helpers should set this as their
174  * &drm_driver.gem_free_object_unlocked callback.
175  */
drm_gem_cma_free_object(struct drm_gem_object * gem_obj)176 void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
177 {
178 	struct drm_gem_cma_object *cma_obj;
179 
180 	cma_obj = to_drm_gem_cma_obj(gem_obj);
181 
182 	if (gem_obj->import_attach) {
183 		if (cma_obj->vaddr)
184 			dma_buf_vunmap(gem_obj->import_attach->dmabuf, cma_obj->vaddr);
185 		drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
186 	} else if (cma_obj->vaddr) {
187 		dma_free_wc(gem_obj->dev->dev, cma_obj->base.size,
188 			    cma_obj->vaddr, cma_obj->paddr);
189 	}
190 
191 	drm_gem_object_release(gem_obj);
192 
193 	kfree(cma_obj);
194 }
195 EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
196 
197 /**
198  * drm_gem_cma_dumb_create_internal - create a dumb buffer object
199  * @file_priv: DRM file-private structure to create the dumb buffer for
200  * @drm: DRM device
201  * @args: IOCTL data
202  *
203  * This aligns the pitch and size arguments to the minimum required. This is
204  * an internal helper that can be wrapped by a driver to account for hardware
205  * with more specific alignment requirements. It should not be used directly
206  * as their &drm_driver.dumb_create callback.
207  *
208  * Returns:
209  * 0 on success or a negative error code on failure.
210  */
drm_gem_cma_dumb_create_internal(struct drm_file * file_priv,struct drm_device * drm,struct drm_mode_create_dumb * args)211 int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv,
212 				     struct drm_device *drm,
213 				     struct drm_mode_create_dumb *args)
214 {
215 	unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
216 	struct drm_gem_cma_object *cma_obj;
217 
218 	if (args->pitch < min_pitch)
219 		args->pitch = min_pitch;
220 
221 	if (args->size < args->pitch * args->height)
222 		args->size = args->pitch * args->height;
223 
224 	cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
225 						 &args->handle);
226 	return PTR_ERR_OR_ZERO(cma_obj);
227 }
228 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create_internal);
229 
230 /**
231  * drm_gem_cma_dumb_create - create a dumb buffer object
232  * @file_priv: DRM file-private structure to create the dumb buffer for
233  * @drm: DRM device
234  * @args: IOCTL data
235  *
236  * This function computes the pitch of the dumb buffer and rounds it up to an
237  * integer number of bytes per pixel. Drivers for hardware that doesn't have
238  * any additional restrictions on the pitch can directly use this function as
239  * their &drm_driver.dumb_create callback.
240  *
241  * For hardware with additional restrictions, drivers can adjust the fields
242  * set up by userspace and pass the IOCTL data along to the
243  * drm_gem_cma_dumb_create_internal() function.
244  *
245  * Returns:
246  * 0 on success or a negative error code on failure.
247  */
drm_gem_cma_dumb_create(struct drm_file * file_priv,struct drm_device * drm,struct drm_mode_create_dumb * args)248 int drm_gem_cma_dumb_create(struct drm_file *file_priv,
249 			    struct drm_device *drm,
250 			    struct drm_mode_create_dumb *args)
251 {
252 	struct drm_gem_cma_object *cma_obj;
253 
254 	args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
255 	args->size = args->pitch * args->height;
256 
257 	cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
258 						 &args->handle);
259 	return PTR_ERR_OR_ZERO(cma_obj);
260 }
261 EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
262 
263 const struct vm_operations_struct drm_gem_cma_vm_ops = {
264 	.open = drm_gem_vm_open,
265 	.close = drm_gem_vm_close,
266 };
267 EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
268 
drm_gem_cma_mmap_obj(struct drm_gem_cma_object * cma_obj,struct vm_area_struct * vma)269 static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
270 				struct vm_area_struct *vma)
271 {
272 	int ret;
273 
274 	/*
275 	 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
276 	 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
277 	 * the whole buffer.
278 	 */
279 	vma->vm_flags &= ~VM_PFNMAP;
280 	vma->vm_pgoff = 0;
281 
282 	ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
283 			  cma_obj->paddr, vma->vm_end - vma->vm_start);
284 	if (ret)
285 		drm_gem_vm_close(vma);
286 
287 	return ret;
288 }
289 
290 /**
291  * drm_gem_cma_mmap - memory-map a CMA GEM object
292  * @filp: file object
293  * @vma: VMA for the area to be mapped
294  *
295  * This function implements an augmented version of the GEM DRM file mmap
296  * operation for CMA objects: In addition to the usual GEM VMA setup it
297  * immediately faults in the entire object instead of using on-demaind
298  * faulting. Drivers which employ the CMA helpers should use this function
299  * as their ->mmap() handler in the DRM device file's file_operations
300  * structure.
301  *
302  * Instead of directly referencing this function, drivers should use the
303  * DEFINE_DRM_GEM_CMA_FOPS().macro.
304  *
305  * Returns:
306  * 0 on success or a negative error code on failure.
307  */
drm_gem_cma_mmap(struct file * filp,struct vm_area_struct * vma)308 int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
309 {
310 	struct drm_gem_cma_object *cma_obj;
311 	struct drm_gem_object *gem_obj;
312 	int ret;
313 
314 	ret = drm_gem_mmap(filp, vma);
315 	if (ret)
316 		return ret;
317 
318 	gem_obj = vma->vm_private_data;
319 	cma_obj = to_drm_gem_cma_obj(gem_obj);
320 
321 	return drm_gem_cma_mmap_obj(cma_obj, vma);
322 }
323 EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
324 
325 #ifndef CONFIG_MMU
326 /**
327  * drm_gem_cma_get_unmapped_area - propose address for mapping in noMMU cases
328  * @filp: file object
329  * @addr: memory address
330  * @len: buffer size
331  * @pgoff: page offset
332  * @flags: memory flags
333  *
334  * This function is used in noMMU platforms to propose address mapping
335  * for a given buffer.
336  * It's intended to be used as a direct handler for the struct
337  * &file_operations.get_unmapped_area operation.
338  *
339  * Returns:
340  * mapping address on success or a negative error code on failure.
341  */
drm_gem_cma_get_unmapped_area(struct file * filp,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)342 unsigned long drm_gem_cma_get_unmapped_area(struct file *filp,
343 					    unsigned long addr,
344 					    unsigned long len,
345 					    unsigned long pgoff,
346 					    unsigned long flags)
347 {
348 	struct drm_gem_cma_object *cma_obj;
349 	struct drm_gem_object *obj = NULL;
350 	struct drm_file *priv = filp->private_data;
351 	struct drm_device *dev = priv->minor->dev;
352 	struct drm_vma_offset_node *node;
353 
354 	if (drm_dev_is_unplugged(dev))
355 		return -ENODEV;
356 
357 	drm_vma_offset_lock_lookup(dev->vma_offset_manager);
358 	node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
359 						  pgoff,
360 						  len >> PAGE_SHIFT);
361 	if (likely(node)) {
362 		obj = container_of(node, struct drm_gem_object, vma_node);
363 		/*
364 		 * When the object is being freed, after it hits 0-refcnt it
365 		 * proceeds to tear down the object. In the process it will
366 		 * attempt to remove the VMA offset and so acquire this
367 		 * mgr->vm_lock.  Therefore if we find an object with a 0-refcnt
368 		 * that matches our range, we know it is in the process of being
369 		 * destroyed and will be freed as soon as we release the lock -
370 		 * so we have to check for the 0-refcnted object and treat it as
371 		 * invalid.
372 		 */
373 		if (!kref_get_unless_zero(&obj->refcount))
374 			obj = NULL;
375 	}
376 
377 	drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
378 
379 	if (!obj)
380 		return -EINVAL;
381 
382 	if (!drm_vma_node_is_allowed(node, priv)) {
383 		drm_gem_object_put_unlocked(obj);
384 		return -EACCES;
385 	}
386 
387 	cma_obj = to_drm_gem_cma_obj(obj);
388 
389 	drm_gem_object_put_unlocked(obj);
390 
391 	return cma_obj->vaddr ? (unsigned long)cma_obj->vaddr : -EINVAL;
392 }
393 EXPORT_SYMBOL_GPL(drm_gem_cma_get_unmapped_area);
394 #endif
395 
396 /**
397  * drm_gem_cma_print_info() - Print &drm_gem_cma_object info for debugfs
398  * @p: DRM printer
399  * @indent: Tab indentation level
400  * @obj: GEM object
401  *
402  * This function can be used as the &drm_driver->gem_print_info callback.
403  * It prints paddr and vaddr for use in e.g. debugfs output.
404  */
drm_gem_cma_print_info(struct drm_printer * p,unsigned int indent,const struct drm_gem_object * obj)405 void drm_gem_cma_print_info(struct drm_printer *p, unsigned int indent,
406 			    const struct drm_gem_object *obj)
407 {
408 	const struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
409 
410 	drm_printf_indent(p, indent, "paddr=%pad\n", &cma_obj->paddr);
411 	drm_printf_indent(p, indent, "vaddr=%p\n", cma_obj->vaddr);
412 }
413 EXPORT_SYMBOL(drm_gem_cma_print_info);
414 
415 /**
416  * drm_gem_cma_prime_get_sg_table - provide a scatter/gather table of pinned
417  *     pages for a CMA GEM object
418  * @obj: GEM object
419  *
420  * This function exports a scatter/gather table suitable for PRIME usage by
421  * calling the standard DMA mapping API. Drivers using the CMA helpers should
422  * set this as their &drm_driver.gem_prime_get_sg_table callback.
423  *
424  * Returns:
425  * A pointer to the scatter/gather table of pinned pages or NULL on failure.
426  */
drm_gem_cma_prime_get_sg_table(struct drm_gem_object * obj)427 struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj)
428 {
429 	struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
430 	struct sg_table *sgt;
431 	int ret;
432 
433 	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
434 	if (!sgt)
435 		return ERR_PTR(-ENOMEM);
436 
437 	ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr,
438 			      cma_obj->paddr, obj->size);
439 	if (ret < 0)
440 		goto out;
441 
442 	return sgt;
443 
444 out:
445 	kfree(sgt);
446 	return ERR_PTR(ret);
447 }
448 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table);
449 
450 /**
451  * drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another
452  *     driver's scatter/gather table of pinned pages
453  * @dev: device to import into
454  * @attach: DMA-BUF attachment
455  * @sgt: scatter/gather table of pinned pages
456  *
457  * This function imports a scatter/gather table exported via DMA-BUF by
458  * another driver. Imported buffers must be physically contiguous in memory
459  * (i.e. the scatter/gather table must contain a single entry). Drivers that
460  * use the CMA helpers should set this as their
461  * &drm_driver.gem_prime_import_sg_table callback.
462  *
463  * Returns:
464  * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
465  * error code on failure.
466  */
467 struct drm_gem_object *
drm_gem_cma_prime_import_sg_table(struct drm_device * dev,struct dma_buf_attachment * attach,struct sg_table * sgt)468 drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
469 				  struct dma_buf_attachment *attach,
470 				  struct sg_table *sgt)
471 {
472 	struct drm_gem_cma_object *cma_obj;
473 
474 	if (sgt->nents != 1) {
475 		/* check if the entries in the sg_table are contiguous */
476 		dma_addr_t next_addr = sg_dma_address(sgt->sgl);
477 		struct scatterlist *s;
478 		unsigned int i;
479 
480 		for_each_sg(sgt->sgl, s, sgt->nents, i) {
481 			/*
482 			 * sg_dma_address(s) is only valid for entries
483 			 * that have sg_dma_len(s) != 0
484 			 */
485 			if (!sg_dma_len(s))
486 				continue;
487 
488 			if (sg_dma_address(s) != next_addr)
489 				return ERR_PTR(-EINVAL);
490 
491 			next_addr = sg_dma_address(s) + sg_dma_len(s);
492 		}
493 	}
494 
495 	/* Create a CMA GEM buffer. */
496 	cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size);
497 	if (IS_ERR(cma_obj))
498 		return ERR_CAST(cma_obj);
499 
500 	cma_obj->paddr = sg_dma_address(sgt->sgl);
501 	cma_obj->sgt = sgt;
502 
503 	DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size);
504 
505 	return &cma_obj->base;
506 }
507 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
508 
509 /**
510  * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
511  * @obj: GEM object
512  * @vma: VMA for the area to be mapped
513  *
514  * This function maps a buffer imported via DRM PRIME into a userspace
515  * process's address space. Drivers that use the CMA helpers should set this
516  * as their &drm_driver.gem_prime_mmap callback.
517  *
518  * Returns:
519  * 0 on success or a negative error code on failure.
520  */
drm_gem_cma_prime_mmap(struct drm_gem_object * obj,struct vm_area_struct * vma)521 int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
522 			   struct vm_area_struct *vma)
523 {
524 	struct drm_gem_cma_object *cma_obj;
525 	int ret;
526 
527 	ret = drm_gem_mmap_obj(obj, obj->size, vma);
528 	if (ret < 0)
529 		return ret;
530 
531 	cma_obj = to_drm_gem_cma_obj(obj);
532 	return drm_gem_cma_mmap_obj(cma_obj, vma);
533 }
534 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
535 
536 /**
537  * drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual
538  *     address space
539  * @obj: GEM object
540  *
541  * This function maps a buffer exported via DRM PRIME into the kernel's
542  * virtual address space. Since the CMA buffers are already mapped into the
543  * kernel virtual address space this simply returns the cached virtual
544  * address. Drivers using the CMA helpers should set this as their DRM
545  * driver's &drm_driver.gem_prime_vmap callback.
546  *
547  * Returns:
548  * The kernel virtual address of the CMA GEM object's backing store.
549  */
drm_gem_cma_prime_vmap(struct drm_gem_object * obj)550 void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
551 {
552 	struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
553 
554 	return cma_obj->vaddr;
555 }
556 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
557 
558 /**
559  * drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual
560  *     address space
561  * @obj: GEM object
562  * @vaddr: kernel virtual address where the CMA GEM object was mapped
563  *
564  * This function removes a buffer exported via DRM PRIME from the kernel's
565  * virtual address space. This is a no-op because CMA buffers cannot be
566  * unmapped from kernel space. Drivers using the CMA helpers should set this
567  * as their &drm_driver.gem_prime_vunmap callback.
568  */
drm_gem_cma_prime_vunmap(struct drm_gem_object * obj,void * vaddr)569 void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
570 {
571 	/* Nothing to do */
572 }
573 EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);
574 
575 static const struct drm_gem_object_funcs drm_cma_gem_default_funcs = {
576 	.free = drm_gem_cma_free_object,
577 	.print_info = drm_gem_cma_print_info,
578 	.get_sg_table = drm_gem_cma_prime_get_sg_table,
579 	.vmap = drm_gem_cma_prime_vmap,
580 	.vm_ops = &drm_gem_cma_vm_ops,
581 };
582 
583 /**
584  * drm_cma_gem_create_object_default_funcs - Create a CMA GEM object with a
585  *                                           default function table
586  * @dev: DRM device
587  * @size: Size of the object to allocate
588  *
589  * This sets the GEM object functions to the default CMA helper functions.
590  * This function can be used as the &drm_driver.gem_create_object callback.
591  *
592  * Returns:
593  * A pointer to a allocated GEM object or an error pointer on failure.
594  */
595 struct drm_gem_object *
drm_cma_gem_create_object_default_funcs(struct drm_device * dev,size_t size)596 drm_cma_gem_create_object_default_funcs(struct drm_device *dev, size_t size)
597 {
598 	struct drm_gem_cma_object *cma_obj;
599 
600 	cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
601 	if (!cma_obj)
602 		return NULL;
603 
604 	cma_obj->base.funcs = &drm_cma_gem_default_funcs;
605 
606 	return &cma_obj->base;
607 }
608 EXPORT_SYMBOL(drm_cma_gem_create_object_default_funcs);
609 
610 /**
611  * drm_gem_cma_prime_import_sg_table_vmap - PRIME import another driver's
612  *	scatter/gather table and get the virtual address of the buffer
613  * @dev: DRM device
614  * @attach: DMA-BUF attachment
615  * @sgt: Scatter/gather table of pinned pages
616  *
617  * This function imports a scatter/gather table using
618  * drm_gem_cma_prime_import_sg_table() and uses dma_buf_vmap() to get the kernel
619  * virtual address. This ensures that a CMA GEM object always has its virtual
620  * address set. This address is released when the object is freed.
621  *
622  * This function can be used as the &drm_driver.gem_prime_import_sg_table
623  * callback. The DRM_GEM_CMA_VMAP_DRIVER_OPS() macro provides a shortcut to set
624  * the necessary DRM driver operations.
625  *
626  * Returns:
627  * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
628  * error code on failure.
629  */
630 struct drm_gem_object *
drm_gem_cma_prime_import_sg_table_vmap(struct drm_device * dev,struct dma_buf_attachment * attach,struct sg_table * sgt)631 drm_gem_cma_prime_import_sg_table_vmap(struct drm_device *dev,
632 				       struct dma_buf_attachment *attach,
633 				       struct sg_table *sgt)
634 {
635 	struct drm_gem_cma_object *cma_obj;
636 	struct drm_gem_object *obj;
637 	void *vaddr;
638 
639 	vaddr = dma_buf_vmap(attach->dmabuf);
640 	if (!vaddr) {
641 		DRM_ERROR("Failed to vmap PRIME buffer\n");
642 		return ERR_PTR(-ENOMEM);
643 	}
644 
645 	obj = drm_gem_cma_prime_import_sg_table(dev, attach, sgt);
646 	if (IS_ERR(obj)) {
647 		dma_buf_vunmap(attach->dmabuf, vaddr);
648 		return obj;
649 	}
650 
651 	cma_obj = to_drm_gem_cma_obj(obj);
652 	cma_obj->vaddr = vaddr;
653 
654 	return obj;
655 }
656 EXPORT_SYMBOL(drm_gem_cma_prime_import_sg_table_vmap);
657