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1/*
2 * drm gem CMA (contiguous memory allocator) helper functions
3 *
4 * Copyright (C) 2012 Sascha Hauer, Pengutronix
5 *
6 * Based on Samsung Exynos code
7 *
8 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 */
19
20#include <linux/mm.h>
21#include <linux/slab.h>
22#include <linux/mutex.h>
23#include <linux/export.h>
24#include <linux/dma-buf.h>
25#include <linux/dma-mapping.h>
26
27#include <drm/drmP.h>
28#include <drm/drm.h>
29#include <drm/drm_gem_cma_helper.h>
30#include <drm/drm_vma_manager.h>
31
32/**
33 * DOC: cma helpers
34 *
35 * The Contiguous Memory Allocator reserves a pool of memory at early boot
36 * that is used to service requests for large blocks of contiguous memory.
37 *
38 * The DRM GEM/CMA helpers use this allocator as a means to provide buffer
39 * objects that are physically contiguous in memory. This is useful for
40 * display drivers that are unable to map scattered buffers via an IOMMU.
41 */
42
43/**
44 * __drm_gem_cma_create - Create a GEM CMA object without allocating memory
45 * @drm: DRM device
46 * @size: size of the object to allocate
47 *
48 * This function creates and initializes a GEM CMA object of the given size,
49 * but doesn't allocate any memory to back the object.
50 *
51 * Returns:
52 * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
53 * error code on failure.
54 */
55static struct drm_gem_cma_object *
56__drm_gem_cma_create(struct drm_device *drm, size_t size)
57{
58 struct drm_gem_cma_object *cma_obj;
59 struct drm_gem_object *gem_obj;
60 int ret;
61
62 if (drm->driver->gem_create_object)
63 gem_obj = drm->driver->gem_create_object(drm, size);
64 else
65 gem_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
66 if (!gem_obj)
67 return ERR_PTR(-ENOMEM);
68 cma_obj = container_of(gem_obj, struct drm_gem_cma_object, base);
69
70 ret = drm_gem_object_init(drm, gem_obj, size);
71 if (ret)
72 goto error;
73
74 ret = drm_gem_create_mmap_offset(gem_obj);
75 if (ret) {
76 drm_gem_object_release(gem_obj);
77 goto error;
78 }
79
80 return cma_obj;
81
82error:
83 kfree(cma_obj);
84 return ERR_PTR(ret);
85}
86
87/**
88 * drm_gem_cma_create - allocate an object with the given size
89 * @drm: DRM device
90 * @size: size of the object to allocate
91 *
92 * This function creates a CMA GEM object and allocates a contiguous chunk of
93 * memory as backing store. The backing memory has the writecombine attribute
94 * set.
95 *
96 * Returns:
97 * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
98 * error code on failure.
99 */
100struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
101 size_t size)
102{
103 struct drm_gem_cma_object *cma_obj;
104 int ret;
105
106 size = round_up(size, PAGE_SIZE);
107
108 cma_obj = __drm_gem_cma_create(drm, size);
109 if (IS_ERR(cma_obj))
110 return cma_obj;
111
112 cma_obj->vaddr = dma_alloc_wc(drm->dev, size, &cma_obj->paddr,
113 GFP_KERNEL | __GFP_NOWARN);
114 if (!cma_obj->vaddr) {
115 dev_err(drm->dev, "failed to allocate buffer with size %zu\n",
116 size);
117 ret = -ENOMEM;
118 goto error;
119 }
120
121 return cma_obj;
122
123error:
124 drm->driver->gem_free_object(&cma_obj->base);
125 return ERR_PTR(ret);
126}
127EXPORT_SYMBOL_GPL(drm_gem_cma_create);
128
129/**
130 * drm_gem_cma_create_with_handle - allocate an object with the given size and
131 * return a GEM handle to it
132 * @file_priv: DRM file-private structure to register the handle for
133 * @drm: DRM device
134 * @size: size of the object to allocate
135 * @handle: return location for the GEM handle
136 *
137 * This function creates a CMA GEM object, allocating a physically contiguous
138 * chunk of memory as backing store. The GEM object is then added to the list
139 * of object associated with the given file and a handle to it is returned.
140 *
141 * Returns:
142 * A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
143 * error code on failure.
144 */
145static struct drm_gem_cma_object *
146drm_gem_cma_create_with_handle(struct drm_file *file_priv,
147 struct drm_device *drm, size_t size,
148 uint32_t *handle)
149{
150 struct drm_gem_cma_object *cma_obj;
151 struct drm_gem_object *gem_obj;
152 int ret;
153
154 cma_obj = drm_gem_cma_create(drm, size);
155 if (IS_ERR(cma_obj))
156 return cma_obj;
157
158 gem_obj = &cma_obj->base;
159
160 /*
161 * allocate a id of idr table where the obj is registered
162 * and handle has the id what user can see.
163 */
164 ret = drm_gem_handle_create(file_priv, gem_obj, handle);
165 if (ret)
166 goto err_handle_create;
167
168 /* drop reference from allocate - handle holds it now. */
169 drm_gem_object_unreference_unlocked(gem_obj);
170
171 return cma_obj;
172
173err_handle_create:
174 drm->driver->gem_free_object(gem_obj);
175
176 return ERR_PTR(ret);
177}
178
179/**
180 * drm_gem_cma_free_object - free resources associated with a CMA GEM object
181 * @gem_obj: GEM object to free
182 *
183 * This function frees the backing memory of the CMA GEM object, cleans up the
184 * GEM object state and frees the memory used to store the object itself.
185 * Drivers using the CMA helpers should set this as their DRM driver's
186 * ->gem_free_object() callback.
187 */
188void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
189{
190 struct drm_gem_cma_object *cma_obj;
191
192 cma_obj = to_drm_gem_cma_obj(gem_obj);
193
194 if (cma_obj->vaddr) {
195 dma_free_wc(gem_obj->dev->dev, cma_obj->base.size,
196 cma_obj->vaddr, cma_obj->paddr);
197 } else if (gem_obj->import_attach) {
198 drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
199 }
200
201 drm_gem_object_release(gem_obj);
202
203 kfree(cma_obj);
204}
205EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
206
207/**
208 * drm_gem_cma_dumb_create_internal - create a dumb buffer object
209 * @file_priv: DRM file-private structure to create the dumb buffer for
210 * @drm: DRM device
211 * @args: IOCTL data
212 *
213 * This aligns the pitch and size arguments to the minimum required. This is
214 * an internal helper that can be wrapped by a driver to account for hardware
215 * with more specific alignment requirements. It should not be used directly
216 * as the ->dumb_create() callback in a DRM driver.
217 *
218 * Returns:
219 * 0 on success or a negative error code on failure.
220 */
221int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv,
222 struct drm_device *drm,
223 struct drm_mode_create_dumb *args)
224{
225 unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
226 struct drm_gem_cma_object *cma_obj;
227
228 if (args->pitch < min_pitch)
229 args->pitch = min_pitch;
230
231 if (args->size < args->pitch * args->height)
232 args->size = args->pitch * args->height;
233
234 cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
235 &args->handle);
236 return PTR_ERR_OR_ZERO(cma_obj);
237}
238EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create_internal);
239
240/**
241 * drm_gem_cma_dumb_create - create a dumb buffer object
242 * @file_priv: DRM file-private structure to create the dumb buffer for
243 * @drm: DRM device
244 * @args: IOCTL data
245 *
246 * This function computes the pitch of the dumb buffer and rounds it up to an
247 * integer number of bytes per pixel. Drivers for hardware that doesn't have
248 * any additional restrictions on the pitch can directly use this function as
249 * their ->dumb_create() callback.
250 *
251 * For hardware with additional restrictions, drivers can adjust the fields
252 * set up by userspace and pass the IOCTL data along to the
253 * drm_gem_cma_dumb_create_internal() function.
254 *
255 * Returns:
256 * 0 on success or a negative error code on failure.
257 */
258int drm_gem_cma_dumb_create(struct drm_file *file_priv,
259 struct drm_device *drm,
260 struct drm_mode_create_dumb *args)
261{
262 struct drm_gem_cma_object *cma_obj;
263
264 args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
265 args->size = args->pitch * args->height;
266
267 cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
268 &args->handle);
269 return PTR_ERR_OR_ZERO(cma_obj);
270}
271EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
272
273/**
274 * drm_gem_cma_dumb_map_offset - return the fake mmap offset for a CMA GEM
275 * object
276 * @file_priv: DRM file-private structure containing the GEM object
277 * @drm: DRM device
278 * @handle: GEM object handle
279 * @offset: return location for the fake mmap offset
280 *
281 * This function look up an object by its handle and returns the fake mmap
282 * offset associated with it. Drivers using the CMA helpers should set this
283 * as their DRM driver's ->dumb_map_offset() callback.
284 *
285 * Returns:
286 * 0 on success or a negative error code on failure.
287 */
288int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
289 struct drm_device *drm, u32 handle,
290 u64 *offset)
291{
292 struct drm_gem_object *gem_obj;
293
294 gem_obj = drm_gem_object_lookup(drm, file_priv, handle);
295 if (!gem_obj) {
296 dev_err(drm->dev, "failed to lookup GEM object\n");
297 return -EINVAL;
298 }
299
300 *offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
301
302 drm_gem_object_unreference_unlocked(gem_obj);
303
304 return 0;
305}
306EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset);
307
308const struct vm_operations_struct drm_gem_cma_vm_ops = {
309 .open = drm_gem_vm_open,
310 .close = drm_gem_vm_close,
311};
312EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
313
314static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
315 struct vm_area_struct *vma)
316{
317 int ret;
318
319 /*
320 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
321 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
322 * the whole buffer.
323 */
324 vma->vm_flags &= ~VM_PFNMAP;
325 vma->vm_pgoff = 0;
326
327 ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
328 cma_obj->paddr, vma->vm_end - vma->vm_start);
329 if (ret)
330 drm_gem_vm_close(vma);
331
332 return ret;
333}
334
335/**
336 * drm_gem_cma_mmap - memory-map a CMA GEM object
337 * @filp: file object
338 * @vma: VMA for the area to be mapped
339 *
340 * This function implements an augmented version of the GEM DRM file mmap
341 * operation for CMA objects: In addition to the usual GEM VMA setup it
342 * immediately faults in the entire object instead of using on-demaind
343 * faulting. Drivers which employ the CMA helpers should use this function
344 * as their ->mmap() handler in the DRM device file's file_operations
345 * structure.
346 *
347 * Returns:
348 * 0 on success or a negative error code on failure.
349 */
350int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
351{
352 struct drm_gem_cma_object *cma_obj;
353 struct drm_gem_object *gem_obj;
354 int ret;
355
356 ret = drm_gem_mmap(filp, vma);
357 if (ret)
358 return ret;
359
360 gem_obj = vma->vm_private_data;
361 cma_obj = to_drm_gem_cma_obj(gem_obj);
362
363 return drm_gem_cma_mmap_obj(cma_obj, vma);
364}
365EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
366
367#ifdef CONFIG_DEBUG_FS
368/**
369 * drm_gem_cma_describe - describe a CMA GEM object for debugfs
370 * @cma_obj: CMA GEM object
371 * @m: debugfs file handle
372 *
373 * This function can be used to dump a human-readable representation of the
374 * CMA GEM object into a synthetic file.
375 */
376void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj,
377 struct seq_file *m)
378{
379 struct drm_gem_object *obj = &cma_obj->base;
380 uint64_t off;
381
382 off = drm_vma_node_start(&obj->vma_node);
383
384 seq_printf(m, "%2d (%2d) %08llx %pad %p %zu",
385 obj->name, obj->refcount.refcount.counter,
386 off, &cma_obj->paddr, cma_obj->vaddr, obj->size);
387
388 seq_printf(m, "\n");
389}
390EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
391#endif
392
393/**
394 * drm_gem_cma_prime_get_sg_table - provide a scatter/gather table of pinned
395 * pages for a CMA GEM object
396 * @obj: GEM object
397 *
398 * This function exports a scatter/gather table suitable for PRIME usage by
399 * calling the standard DMA mapping API. Drivers using the CMA helpers should
400 * set this as their DRM driver's ->gem_prime_get_sg_table() callback.
401 *
402 * Returns:
403 * A pointer to the scatter/gather table of pinned pages or NULL on failure.
404 */
405struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj)
406{
407 struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
408 struct sg_table *sgt;
409 int ret;
410
411 sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
412 if (!sgt)
413 return NULL;
414
415 ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr,
416 cma_obj->paddr, obj->size);
417 if (ret < 0)
418 goto out;
419
420 return sgt;
421
422out:
423 kfree(sgt);
424 return NULL;
425}
426EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table);
427
428/**
429 * drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another
430 * driver's scatter/gather table of pinned pages
431 * @dev: device to import into
432 * @attach: DMA-BUF attachment
433 * @sgt: scatter/gather table of pinned pages
434 *
435 * This function imports a scatter/gather table exported via DMA-BUF by
436 * another driver. Imported buffers must be physically contiguous in memory
437 * (i.e. the scatter/gather table must contain a single entry). Drivers that
438 * use the CMA helpers should set this as their DRM driver's
439 * ->gem_prime_import_sg_table() callback.
440 *
441 * Returns:
442 * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
443 * error code on failure.
444 */
445struct drm_gem_object *
446drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
447 struct dma_buf_attachment *attach,
448 struct sg_table *sgt)
449{
450 struct drm_gem_cma_object *cma_obj;
451
452 if (sgt->nents != 1)
453 return ERR_PTR(-EINVAL);
454
455 /* Create a CMA GEM buffer. */
456 cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size);
457 if (IS_ERR(cma_obj))
458 return ERR_CAST(cma_obj);
459
460 cma_obj->paddr = sg_dma_address(sgt->sgl);
461 cma_obj->sgt = sgt;
462
463 DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size);
464
465 return &cma_obj->base;
466}
467EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
468
469/**
470 * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
471 * @obj: GEM object
472 * @vma: VMA for the area to be mapped
473 *
474 * This function maps a buffer imported via DRM PRIME into a userspace
475 * process's address space. Drivers that use the CMA helpers should set this
476 * as their DRM driver's ->gem_prime_mmap() callback.
477 *
478 * Returns:
479 * 0 on success or a negative error code on failure.
480 */
481int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
482 struct vm_area_struct *vma)
483{
484 struct drm_gem_cma_object *cma_obj;
485 int ret;
486
487 ret = drm_gem_mmap_obj(obj, obj->size, vma);
488 if (ret < 0)
489 return ret;
490
491 cma_obj = to_drm_gem_cma_obj(obj);
492 return drm_gem_cma_mmap_obj(cma_obj, vma);
493}
494EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
495
496/**
497 * drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual
498 * address space
499 * @obj: GEM object
500 *
501 * This function maps a buffer exported via DRM PRIME into the kernel's
502 * virtual address space. Since the CMA buffers are already mapped into the
503 * kernel virtual address space this simply returns the cached virtual
504 * address. Drivers using the CMA helpers should set this as their DRM
505 * driver's ->gem_prime_vmap() callback.
506 *
507 * Returns:
508 * The kernel virtual address of the CMA GEM object's backing store.
509 */
510void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
511{
512 struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
513
514 return cma_obj->vaddr;
515}
516EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
517
518/**
519 * drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual
520 * address space
521 * @obj: GEM object
522 * @vaddr: kernel virtual address where the CMA GEM object was mapped
523 *
524 * This function removes a buffer exported via DRM PRIME from the kernel's
525 * virtual address space. This is a no-op because CMA buffers cannot be
526 * unmapped from kernel space. Drivers using the CMA helpers should set this
527 * as their DRM driver's ->gem_prime_vunmap() callback.
528 */
529void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
530{
531 /* Nothing to do */
532}
533EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);