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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 */
48static struct drm_gem_cma_object *
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
75error:
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 */
93struct 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 drm_dbg(drm, "failed to allocate buffer with size %zu\n",
109 size);
110 ret = -ENOMEM;
111 goto error;
112 }
113
114 return cma_obj;
115
116error:
117 drm_gem_object_put(&cma_obj->base);
118 return ERR_PTR(ret);
119}
120EXPORT_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 */
138static struct drm_gem_cma_object *
139drm_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(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 */
176void 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}
195EXPORT_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 */
211int 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}
228EXPORT_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 */
248int 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}
261EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
262
263const struct vm_operations_struct drm_gem_cma_vm_ops = {
264 .open = drm_gem_vm_open,
265 .close = drm_gem_vm_close,
266};
267EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
268
269static 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 */
308int 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}
323EXPORT_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 */
342unsigned 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(obj);
384 return -EACCES;
385 }
386
387 cma_obj = to_drm_gem_cma_obj(obj);
388
389 drm_gem_object_put(obj);
390
391 return cma_obj->vaddr ? (unsigned long)cma_obj->vaddr : -EINVAL;
392}
393EXPORT_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 */
405void 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}
413EXPORT_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 */
427struct 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
444out:
445 kfree(sgt);
446 return ERR_PTR(ret);
447}
448EXPORT_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 */
467struct drm_gem_object *
468drm_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}
507EXPORT_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 */
521int 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}
534EXPORT_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 */
550void *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}
556EXPORT_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 */
569void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
570{
571 /* Nothing to do */
572}
573EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);
574
575static const struct drm_gem_object_funcs drm_gem_cma_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_gem_cma_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 */
595struct drm_gem_object *
596drm_gem_cma_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_gem_cma_default_funcs;
605
606 return &cma_obj->base;
607}
608EXPORT_SYMBOL(drm_gem_cma_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_DRIVER_OPS_VMAP 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 */
630struct drm_gem_object *
631drm_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}
656EXPORT_SYMBOL(drm_gem_cma_prime_import_sg_table_vmap);