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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_gem_object_unreference_unlocked(&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 /* drop reference from allocate - handle holds it now. */
166 drm_gem_object_unreference_unlocked(gem_obj);
167 if (ret)
168 return ERR_PTR(ret);
169
170 return cma_obj;
171}
172
173/**
174 * drm_gem_cma_free_object - free resources associated with a CMA GEM object
175 * @gem_obj: GEM object to free
176 *
177 * This function frees the backing memory of the CMA GEM object, cleans up the
178 * GEM object state and frees the memory used to store the object itself.
179 * Drivers using the CMA helpers should set this as their DRM driver's
180 * ->gem_free_object() callback.
181 */
182void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
183{
184 struct drm_gem_cma_object *cma_obj;
185
186 cma_obj = to_drm_gem_cma_obj(gem_obj);
187
188 if (cma_obj->vaddr) {
189 dma_free_wc(gem_obj->dev->dev, cma_obj->base.size,
190 cma_obj->vaddr, cma_obj->paddr);
191 } else if (gem_obj->import_attach) {
192 drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
193 }
194
195 drm_gem_object_release(gem_obj);
196
197 kfree(cma_obj);
198}
199EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
200
201/**
202 * drm_gem_cma_dumb_create_internal - create a dumb buffer object
203 * @file_priv: DRM file-private structure to create the dumb buffer for
204 * @drm: DRM device
205 * @args: IOCTL data
206 *
207 * This aligns the pitch and size arguments to the minimum required. This is
208 * an internal helper that can be wrapped by a driver to account for hardware
209 * with more specific alignment requirements. It should not be used directly
210 * as the ->dumb_create() callback in a DRM driver.
211 *
212 * Returns:
213 * 0 on success or a negative error code on failure.
214 */
215int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv,
216 struct drm_device *drm,
217 struct drm_mode_create_dumb *args)
218{
219 unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
220 struct drm_gem_cma_object *cma_obj;
221
222 if (args->pitch < min_pitch)
223 args->pitch = min_pitch;
224
225 if (args->size < args->pitch * args->height)
226 args->size = args->pitch * args->height;
227
228 cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
229 &args->handle);
230 return PTR_ERR_OR_ZERO(cma_obj);
231}
232EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create_internal);
233
234/**
235 * drm_gem_cma_dumb_create - create a dumb buffer object
236 * @file_priv: DRM file-private structure to create the dumb buffer for
237 * @drm: DRM device
238 * @args: IOCTL data
239 *
240 * This function computes the pitch of the dumb buffer and rounds it up to an
241 * integer number of bytes per pixel. Drivers for hardware that doesn't have
242 * any additional restrictions on the pitch can directly use this function as
243 * their ->dumb_create() callback.
244 *
245 * For hardware with additional restrictions, drivers can adjust the fields
246 * set up by userspace and pass the IOCTL data along to the
247 * drm_gem_cma_dumb_create_internal() function.
248 *
249 * Returns:
250 * 0 on success or a negative error code on failure.
251 */
252int drm_gem_cma_dumb_create(struct drm_file *file_priv,
253 struct drm_device *drm,
254 struct drm_mode_create_dumb *args)
255{
256 struct drm_gem_cma_object *cma_obj;
257
258 args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
259 args->size = args->pitch * args->height;
260
261 cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
262 &args->handle);
263 return PTR_ERR_OR_ZERO(cma_obj);
264}
265EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
266
267/**
268 * drm_gem_cma_dumb_map_offset - return the fake mmap offset for a CMA GEM
269 * object
270 * @file_priv: DRM file-private structure containing the GEM object
271 * @drm: DRM device
272 * @handle: GEM object handle
273 * @offset: return location for the fake mmap offset
274 *
275 * This function look up an object by its handle and returns the fake mmap
276 * offset associated with it. Drivers using the CMA helpers should set this
277 * as their DRM driver's ->dumb_map_offset() callback.
278 *
279 * Returns:
280 * 0 on success or a negative error code on failure.
281 */
282int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
283 struct drm_device *drm, u32 handle,
284 u64 *offset)
285{
286 struct drm_gem_object *gem_obj;
287
288 gem_obj = drm_gem_object_lookup(file_priv, handle);
289 if (!gem_obj) {
290 dev_err(drm->dev, "failed to lookup GEM object\n");
291 return -EINVAL;
292 }
293
294 *offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
295
296 drm_gem_object_unreference_unlocked(gem_obj);
297
298 return 0;
299}
300EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset);
301
302const struct vm_operations_struct drm_gem_cma_vm_ops = {
303 .open = drm_gem_vm_open,
304 .close = drm_gem_vm_close,
305};
306EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
307
308static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
309 struct vm_area_struct *vma)
310{
311 int ret;
312
313 /*
314 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
315 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
316 * the whole buffer.
317 */
318 vma->vm_flags &= ~VM_PFNMAP;
319 vma->vm_pgoff = 0;
320
321 ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
322 cma_obj->paddr, vma->vm_end - vma->vm_start);
323 if (ret)
324 drm_gem_vm_close(vma);
325
326 return ret;
327}
328
329/**
330 * drm_gem_cma_mmap - memory-map a CMA GEM object
331 * @filp: file object
332 * @vma: VMA for the area to be mapped
333 *
334 * This function implements an augmented version of the GEM DRM file mmap
335 * operation for CMA objects: In addition to the usual GEM VMA setup it
336 * immediately faults in the entire object instead of using on-demaind
337 * faulting. Drivers which employ the CMA helpers should use this function
338 * as their ->mmap() handler in the DRM device file's file_operations
339 * structure.
340 *
341 * Returns:
342 * 0 on success or a negative error code on failure.
343 */
344int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
345{
346 struct drm_gem_cma_object *cma_obj;
347 struct drm_gem_object *gem_obj;
348 int ret;
349
350 ret = drm_gem_mmap(filp, vma);
351 if (ret)
352 return ret;
353
354 gem_obj = vma->vm_private_data;
355 cma_obj = to_drm_gem_cma_obj(gem_obj);
356
357 return drm_gem_cma_mmap_obj(cma_obj, vma);
358}
359EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
360
361#ifdef CONFIG_DEBUG_FS
362/**
363 * drm_gem_cma_describe - describe a CMA GEM object for debugfs
364 * @cma_obj: CMA GEM object
365 * @m: debugfs file handle
366 *
367 * This function can be used to dump a human-readable representation of the
368 * CMA GEM object into a synthetic file.
369 */
370void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj,
371 struct seq_file *m)
372{
373 struct drm_gem_object *obj = &cma_obj->base;
374 uint64_t off;
375
376 off = drm_vma_node_start(&obj->vma_node);
377
378 seq_printf(m, "%2d (%2d) %08llx %pad %p %zu",
379 obj->name, obj->refcount.refcount.counter,
380 off, &cma_obj->paddr, cma_obj->vaddr, obj->size);
381
382 seq_printf(m, "\n");
383}
384EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
385#endif
386
387/**
388 * drm_gem_cma_prime_get_sg_table - provide a scatter/gather table of pinned
389 * pages for a CMA GEM object
390 * @obj: GEM object
391 *
392 * This function exports a scatter/gather table suitable for PRIME usage by
393 * calling the standard DMA mapping API. Drivers using the CMA helpers should
394 * set this as their DRM driver's ->gem_prime_get_sg_table() callback.
395 *
396 * Returns:
397 * A pointer to the scatter/gather table of pinned pages or NULL on failure.
398 */
399struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj)
400{
401 struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
402 struct sg_table *sgt;
403 int ret;
404
405 sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
406 if (!sgt)
407 return NULL;
408
409 ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr,
410 cma_obj->paddr, obj->size);
411 if (ret < 0)
412 goto out;
413
414 return sgt;
415
416out:
417 kfree(sgt);
418 return NULL;
419}
420EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table);
421
422/**
423 * drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another
424 * driver's scatter/gather table of pinned pages
425 * @dev: device to import into
426 * @attach: DMA-BUF attachment
427 * @sgt: scatter/gather table of pinned pages
428 *
429 * This function imports a scatter/gather table exported via DMA-BUF by
430 * another driver. Imported buffers must be physically contiguous in memory
431 * (i.e. the scatter/gather table must contain a single entry). Drivers that
432 * use the CMA helpers should set this as their DRM driver's
433 * ->gem_prime_import_sg_table() callback.
434 *
435 * Returns:
436 * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
437 * error code on failure.
438 */
439struct drm_gem_object *
440drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
441 struct dma_buf_attachment *attach,
442 struct sg_table *sgt)
443{
444 struct drm_gem_cma_object *cma_obj;
445
446 if (sgt->nents != 1)
447 return ERR_PTR(-EINVAL);
448
449 /* Create a CMA GEM buffer. */
450 cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size);
451 if (IS_ERR(cma_obj))
452 return ERR_CAST(cma_obj);
453
454 cma_obj->paddr = sg_dma_address(sgt->sgl);
455 cma_obj->sgt = sgt;
456
457 DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size);
458
459 return &cma_obj->base;
460}
461EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
462
463/**
464 * drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
465 * @obj: GEM object
466 * @vma: VMA for the area to be mapped
467 *
468 * This function maps a buffer imported via DRM PRIME into a userspace
469 * process's address space. Drivers that use the CMA helpers should set this
470 * as their DRM driver's ->gem_prime_mmap() callback.
471 *
472 * Returns:
473 * 0 on success or a negative error code on failure.
474 */
475int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
476 struct vm_area_struct *vma)
477{
478 struct drm_gem_cma_object *cma_obj;
479 int ret;
480
481 ret = drm_gem_mmap_obj(obj, obj->size, vma);
482 if (ret < 0)
483 return ret;
484
485 cma_obj = to_drm_gem_cma_obj(obj);
486 return drm_gem_cma_mmap_obj(cma_obj, vma);
487}
488EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
489
490/**
491 * drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual
492 * address space
493 * @obj: GEM object
494 *
495 * This function maps a buffer exported via DRM PRIME into the kernel's
496 * virtual address space. Since the CMA buffers are already mapped into the
497 * kernel virtual address space this simply returns the cached virtual
498 * address. Drivers using the CMA helpers should set this as their DRM
499 * driver's ->gem_prime_vmap() callback.
500 *
501 * Returns:
502 * The kernel virtual address of the CMA GEM object's backing store.
503 */
504void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
505{
506 struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
507
508 return cma_obj->vaddr;
509}
510EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
511
512/**
513 * drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual
514 * address space
515 * @obj: GEM object
516 * @vaddr: kernel virtual address where the CMA GEM object was mapped
517 *
518 * This function removes a buffer exported via DRM PRIME from the kernel's
519 * virtual address space. This is a no-op because CMA buffers cannot be
520 * unmapped from kernel space. Drivers using the CMA helpers should set this
521 * as their DRM driver's ->gem_prime_vunmap() callback.
522 */
523void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
524{
525 /* Nothing to do */
526}
527EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);