1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* exynos_drm_gem.c
3  *
4  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
5  * Author: Inki Dae <inki.dae@samsung.com>
6  */
7 
8 
9 #include <linux/dma-buf.h>
10 #include <linux/pfn_t.h>
11 #include <linux/shmem_fs.h>
12 
13 #include <drm/drm_prime.h>
14 #include <drm/drm_vma_manager.h>
15 #include <drm/exynos_drm.h>
16 
17 #include "exynos_drm_drv.h"
18 #include "exynos_drm_gem.h"
19 
20 static int exynos_drm_alloc_buf(struct exynos_drm_gem *exynos_gem, bool kvmap)
21 {
22 	struct drm_device *dev = exynos_gem->base.dev;
23 	unsigned long attr = 0;
24 
25 	if (exynos_gem->dma_addr) {
26 		DRM_DEV_DEBUG_KMS(to_dma_dev(dev), "already allocated.\n");
27 		return 0;
28 	}
29 
30 	/*
31 	 * if EXYNOS_BO_CONTIG, fully physically contiguous memory
32 	 * region will be allocated else physically contiguous
33 	 * as possible.
34 	 */
35 	if (!(exynos_gem->flags & EXYNOS_BO_NONCONTIG))
36 		attr |= DMA_ATTR_FORCE_CONTIGUOUS;
37 
38 	/*
39 	 * if EXYNOS_BO_WC or EXYNOS_BO_NONCACHABLE, writecombine mapping
40 	 * else cachable mapping.
41 	 */
42 	if (exynos_gem->flags & EXYNOS_BO_WC ||
43 			!(exynos_gem->flags & EXYNOS_BO_CACHABLE))
44 		attr |= DMA_ATTR_WRITE_COMBINE;
45 	else
46 		attr |= DMA_ATTR_NON_CONSISTENT;
47 
48 	/* FBDev emulation requires kernel mapping */
49 	if (!kvmap)
50 		attr |= DMA_ATTR_NO_KERNEL_MAPPING;
51 
52 	exynos_gem->dma_attrs = attr;
53 	exynos_gem->cookie = dma_alloc_attrs(to_dma_dev(dev), exynos_gem->size,
54 					     &exynos_gem->dma_addr, GFP_KERNEL,
55 					     exynos_gem->dma_attrs);
56 	if (!exynos_gem->cookie) {
57 		DRM_DEV_ERROR(to_dma_dev(dev), "failed to allocate buffer.\n");
58 		return -ENOMEM;
59 	}
60 
61 	if (kvmap)
62 		exynos_gem->kvaddr = exynos_gem->cookie;
63 
64 	DRM_DEV_DEBUG_KMS(to_dma_dev(dev), "dma_addr(0x%lx), size(0x%lx)\n",
65 			(unsigned long)exynos_gem->dma_addr, exynos_gem->size);
66 	return 0;
67 }
68 
69 static void exynos_drm_free_buf(struct exynos_drm_gem *exynos_gem)
70 {
71 	struct drm_device *dev = exynos_gem->base.dev;
72 
73 	if (!exynos_gem->dma_addr) {
74 		DRM_DEV_DEBUG_KMS(dev->dev, "dma_addr is invalid.\n");
75 		return;
76 	}
77 
78 	DRM_DEV_DEBUG_KMS(dev->dev, "dma_addr(0x%lx), size(0x%lx)\n",
79 			(unsigned long)exynos_gem->dma_addr, exynos_gem->size);
80 
81 	dma_free_attrs(to_dma_dev(dev), exynos_gem->size, exynos_gem->cookie,
82 			(dma_addr_t)exynos_gem->dma_addr,
83 			exynos_gem->dma_attrs);
84 }
85 
86 static int exynos_drm_gem_handle_create(struct drm_gem_object *obj,
87 					struct drm_file *file_priv,
88 					unsigned int *handle)
89 {
90 	int ret;
91 
92 	/*
93 	 * allocate a id of idr table where the obj is registered
94 	 * and handle has the id what user can see.
95 	 */
96 	ret = drm_gem_handle_create(file_priv, obj, handle);
97 	if (ret)
98 		return ret;
99 
100 	DRM_DEV_DEBUG_KMS(to_dma_dev(obj->dev), "gem handle = 0x%x\n", *handle);
101 
102 	/* drop reference from allocate - handle holds it now. */
103 	drm_gem_object_put(obj);
104 
105 	return 0;
106 }
107 
108 void exynos_drm_gem_destroy(struct exynos_drm_gem *exynos_gem)
109 {
110 	struct drm_gem_object *obj = &exynos_gem->base;
111 
112 	DRM_DEV_DEBUG_KMS(to_dma_dev(obj->dev), "handle count = %d\n",
113 			  obj->handle_count);
114 
115 	/*
116 	 * do not release memory region from exporter.
117 	 *
118 	 * the region will be released by exporter
119 	 * once dmabuf's refcount becomes 0.
120 	 */
121 	if (obj->import_attach)
122 		drm_prime_gem_destroy(obj, exynos_gem->sgt);
123 	else
124 		exynos_drm_free_buf(exynos_gem);
125 
126 	/* release file pointer to gem object. */
127 	drm_gem_object_release(obj);
128 
129 	kfree(exynos_gem);
130 }
131 
132 static const struct vm_operations_struct exynos_drm_gem_vm_ops = {
133 	.open = drm_gem_vm_open,
134 	.close = drm_gem_vm_close,
135 };
136 
137 static const struct drm_gem_object_funcs exynos_drm_gem_object_funcs = {
138 	.free = exynos_drm_gem_free_object,
139 	.get_sg_table = exynos_drm_gem_prime_get_sg_table,
140 	.vmap = exynos_drm_gem_prime_vmap,
141 	.vunmap	= exynos_drm_gem_prime_vunmap,
142 	.vm_ops = &exynos_drm_gem_vm_ops,
143 };
144 
145 static struct exynos_drm_gem *exynos_drm_gem_init(struct drm_device *dev,
146 						  unsigned long size)
147 {
148 	struct exynos_drm_gem *exynos_gem;
149 	struct drm_gem_object *obj;
150 	int ret;
151 
152 	exynos_gem = kzalloc(sizeof(*exynos_gem), GFP_KERNEL);
153 	if (!exynos_gem)
154 		return ERR_PTR(-ENOMEM);
155 
156 	exynos_gem->size = size;
157 	obj = &exynos_gem->base;
158 
159 	obj->funcs = &exynos_drm_gem_object_funcs;
160 
161 	ret = drm_gem_object_init(dev, obj, size);
162 	if (ret < 0) {
163 		DRM_DEV_ERROR(dev->dev, "failed to initialize gem object\n");
164 		kfree(exynos_gem);
165 		return ERR_PTR(ret);
166 	}
167 
168 	ret = drm_gem_create_mmap_offset(obj);
169 	if (ret < 0) {
170 		drm_gem_object_release(obj);
171 		kfree(exynos_gem);
172 		return ERR_PTR(ret);
173 	}
174 
175 	DRM_DEV_DEBUG_KMS(dev->dev, "created file object = %pK\n", obj->filp);
176 
177 	return exynos_gem;
178 }
179 
180 struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
181 					     unsigned int flags,
182 					     unsigned long size,
183 					     bool kvmap)
184 {
185 	struct exynos_drm_gem *exynos_gem;
186 	int ret;
187 
188 	if (flags & ~(EXYNOS_BO_MASK)) {
189 		DRM_DEV_ERROR(dev->dev,
190 			      "invalid GEM buffer flags: %u\n", flags);
191 		return ERR_PTR(-EINVAL);
192 	}
193 
194 	if (!size) {
195 		DRM_DEV_ERROR(dev->dev, "invalid GEM buffer size: %lu\n", size);
196 		return ERR_PTR(-EINVAL);
197 	}
198 
199 	size = roundup(size, PAGE_SIZE);
200 
201 	exynos_gem = exynos_drm_gem_init(dev, size);
202 	if (IS_ERR(exynos_gem))
203 		return exynos_gem;
204 
205 	if (!is_drm_iommu_supported(dev) && (flags & EXYNOS_BO_NONCONTIG)) {
206 		/*
207 		 * when no IOMMU is available, all allocated buffers are
208 		 * contiguous anyway, so drop EXYNOS_BO_NONCONTIG flag
209 		 */
210 		flags &= ~EXYNOS_BO_NONCONTIG;
211 		DRM_WARN("Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer\n");
212 	}
213 
214 	/* set memory type and cache attribute from user side. */
215 	exynos_gem->flags = flags;
216 
217 	ret = exynos_drm_alloc_buf(exynos_gem, kvmap);
218 	if (ret < 0) {
219 		drm_gem_object_release(&exynos_gem->base);
220 		kfree(exynos_gem);
221 		return ERR_PTR(ret);
222 	}
223 
224 	return exynos_gem;
225 }
226 
227 int exynos_drm_gem_create_ioctl(struct drm_device *dev, void *data,
228 				struct drm_file *file_priv)
229 {
230 	struct drm_exynos_gem_create *args = data;
231 	struct exynos_drm_gem *exynos_gem;
232 	int ret;
233 
234 	exynos_gem = exynos_drm_gem_create(dev, args->flags, args->size, false);
235 	if (IS_ERR(exynos_gem))
236 		return PTR_ERR(exynos_gem);
237 
238 	ret = exynos_drm_gem_handle_create(&exynos_gem->base, file_priv,
239 					   &args->handle);
240 	if (ret) {
241 		exynos_drm_gem_destroy(exynos_gem);
242 		return ret;
243 	}
244 
245 	return 0;
246 }
247 
248 int exynos_drm_gem_map_ioctl(struct drm_device *dev, void *data,
249 			     struct drm_file *file_priv)
250 {
251 	struct drm_exynos_gem_map *args = data;
252 
253 	return drm_gem_dumb_map_offset(file_priv, dev, args->handle,
254 				       &args->offset);
255 }
256 
257 struct exynos_drm_gem *exynos_drm_gem_get(struct drm_file *filp,
258 					  unsigned int gem_handle)
259 {
260 	struct drm_gem_object *obj;
261 
262 	obj = drm_gem_object_lookup(filp, gem_handle);
263 	if (!obj)
264 		return NULL;
265 	return to_exynos_gem(obj);
266 }
267 
268 static int exynos_drm_gem_mmap_buffer(struct exynos_drm_gem *exynos_gem,
269 				      struct vm_area_struct *vma)
270 {
271 	struct drm_device *drm_dev = exynos_gem->base.dev;
272 	unsigned long vm_size;
273 	int ret;
274 
275 	vma->vm_flags &= ~VM_PFNMAP;
276 	vma->vm_pgoff = 0;
277 
278 	vm_size = vma->vm_end - vma->vm_start;
279 
280 	/* check if user-requested size is valid. */
281 	if (vm_size > exynos_gem->size)
282 		return -EINVAL;
283 
284 	ret = dma_mmap_attrs(to_dma_dev(drm_dev), vma, exynos_gem->cookie,
285 			     exynos_gem->dma_addr, exynos_gem->size,
286 			     exynos_gem->dma_attrs);
287 	if (ret < 0) {
288 		DRM_ERROR("failed to mmap.\n");
289 		return ret;
290 	}
291 
292 	return 0;
293 }
294 
295 int exynos_drm_gem_get_ioctl(struct drm_device *dev, void *data,
296 				      struct drm_file *file_priv)
297 {
298 	struct exynos_drm_gem *exynos_gem;
299 	struct drm_exynos_gem_info *args = data;
300 	struct drm_gem_object *obj;
301 
302 	obj = drm_gem_object_lookup(file_priv, args->handle);
303 	if (!obj) {
304 		DRM_DEV_ERROR(dev->dev, "failed to lookup gem object.\n");
305 		return -EINVAL;
306 	}
307 
308 	exynos_gem = to_exynos_gem(obj);
309 
310 	args->flags = exynos_gem->flags;
311 	args->size = exynos_gem->size;
312 
313 	drm_gem_object_put(obj);
314 
315 	return 0;
316 }
317 
318 void exynos_drm_gem_free_object(struct drm_gem_object *obj)
319 {
320 	exynos_drm_gem_destroy(to_exynos_gem(obj));
321 }
322 
323 int exynos_drm_gem_dumb_create(struct drm_file *file_priv,
324 			       struct drm_device *dev,
325 			       struct drm_mode_create_dumb *args)
326 {
327 	struct exynos_drm_gem *exynos_gem;
328 	unsigned int flags;
329 	int ret;
330 
331 	/*
332 	 * allocate memory to be used for framebuffer.
333 	 * - this callback would be called by user application
334 	 *	with DRM_IOCTL_MODE_CREATE_DUMB command.
335 	 */
336 
337 	args->pitch = args->width * ((args->bpp + 7) / 8);
338 	args->size = args->pitch * args->height;
339 
340 	if (is_drm_iommu_supported(dev))
341 		flags = EXYNOS_BO_NONCONTIG | EXYNOS_BO_WC;
342 	else
343 		flags = EXYNOS_BO_CONTIG | EXYNOS_BO_WC;
344 
345 	exynos_gem = exynos_drm_gem_create(dev, flags, args->size, false);
346 	if (IS_ERR(exynos_gem)) {
347 		dev_warn(dev->dev, "FB allocation failed.\n");
348 		return PTR_ERR(exynos_gem);
349 	}
350 
351 	ret = exynos_drm_gem_handle_create(&exynos_gem->base, file_priv,
352 					   &args->handle);
353 	if (ret) {
354 		exynos_drm_gem_destroy(exynos_gem);
355 		return ret;
356 	}
357 
358 	return 0;
359 }
360 
361 static int exynos_drm_gem_mmap_obj(struct drm_gem_object *obj,
362 				   struct vm_area_struct *vma)
363 {
364 	struct exynos_drm_gem *exynos_gem = to_exynos_gem(obj);
365 	int ret;
366 
367 	DRM_DEV_DEBUG_KMS(to_dma_dev(obj->dev), "flags = 0x%x\n",
368 			  exynos_gem->flags);
369 
370 	/* non-cachable as default. */
371 	if (exynos_gem->flags & EXYNOS_BO_CACHABLE)
372 		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
373 	else if (exynos_gem->flags & EXYNOS_BO_WC)
374 		vma->vm_page_prot =
375 			pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
376 	else
377 		vma->vm_page_prot =
378 			pgprot_noncached(vm_get_page_prot(vma->vm_flags));
379 
380 	ret = exynos_drm_gem_mmap_buffer(exynos_gem, vma);
381 	if (ret)
382 		goto err_close_vm;
383 
384 	return ret;
385 
386 err_close_vm:
387 	drm_gem_vm_close(vma);
388 
389 	return ret;
390 }
391 
392 int exynos_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
393 {
394 	struct drm_gem_object *obj;
395 	int ret;
396 
397 	/* set vm_area_struct. */
398 	ret = drm_gem_mmap(filp, vma);
399 	if (ret < 0) {
400 		DRM_ERROR("failed to mmap.\n");
401 		return ret;
402 	}
403 
404 	obj = vma->vm_private_data;
405 
406 	if (obj->import_attach)
407 		return dma_buf_mmap(obj->dma_buf, vma, 0);
408 
409 	return exynos_drm_gem_mmap_obj(obj, vma);
410 }
411 
412 /* low-level interface prime helpers */
413 struct drm_gem_object *exynos_drm_gem_prime_import(struct drm_device *dev,
414 					    struct dma_buf *dma_buf)
415 {
416 	return drm_gem_prime_import_dev(dev, dma_buf, to_dma_dev(dev));
417 }
418 
419 struct sg_table *exynos_drm_gem_prime_get_sg_table(struct drm_gem_object *obj)
420 {
421 	struct exynos_drm_gem *exynos_gem = to_exynos_gem(obj);
422 	struct drm_device *drm_dev = obj->dev;
423 	struct sg_table *sgt;
424 	int ret;
425 
426 	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
427 	if (!sgt)
428 		return ERR_PTR(-ENOMEM);
429 
430 	ret = dma_get_sgtable_attrs(to_dma_dev(drm_dev), sgt, exynos_gem->cookie,
431 				    exynos_gem->dma_addr, exynos_gem->size,
432 				    exynos_gem->dma_attrs);
433 	if (ret) {
434 		DRM_ERROR("failed to get sgtable, %d\n", ret);
435 		kfree(sgt);
436 		return ERR_PTR(ret);
437 	}
438 
439 	return sgt;
440 }
441 
442 struct drm_gem_object *
443 exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
444 				     struct dma_buf_attachment *attach,
445 				     struct sg_table *sgt)
446 {
447 	struct exynos_drm_gem *exynos_gem;
448 
449 	if (sgt->nents < 1)
450 		return ERR_PTR(-EINVAL);
451 
452 	/*
453 	 * Check if the provided buffer has been mapped as contiguous
454 	 * into DMA address space.
455 	 */
456 	if (sgt->nents > 1) {
457 		dma_addr_t next_addr = sg_dma_address(sgt->sgl);
458 		struct scatterlist *s;
459 		unsigned int i;
460 
461 		for_each_sg(sgt->sgl, s, sgt->nents, i) {
462 			if (!sg_dma_len(s))
463 				break;
464 			if (sg_dma_address(s) != next_addr) {
465 				DRM_ERROR("buffer chunks must be mapped contiguously");
466 				return ERR_PTR(-EINVAL);
467 			}
468 			next_addr = sg_dma_address(s) + sg_dma_len(s);
469 		}
470 	}
471 
472 	exynos_gem = exynos_drm_gem_init(dev, attach->dmabuf->size);
473 	if (IS_ERR(exynos_gem))
474 		return ERR_CAST(exynos_gem);
475 
476 	/*
477 	 * Buffer has been mapped as contiguous into DMA address space,
478 	 * but if there is IOMMU, it can be either CONTIG or NONCONTIG.
479 	 * We assume a simplified logic below:
480 	 */
481 	if (is_drm_iommu_supported(dev))
482 		exynos_gem->flags |= EXYNOS_BO_NONCONTIG;
483 	else
484 		exynos_gem->flags |= EXYNOS_BO_CONTIG;
485 
486 	exynos_gem->dma_addr = sg_dma_address(sgt->sgl);
487 	exynos_gem->sgt = sgt;
488 	return &exynos_gem->base;
489 }
490 
491 void *exynos_drm_gem_prime_vmap(struct drm_gem_object *obj)
492 {
493 	return NULL;
494 }
495 
496 void exynos_drm_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
497 {
498 	/* Nothing to do */
499 }
500 
501 int exynos_drm_gem_prime_mmap(struct drm_gem_object *obj,
502 			      struct vm_area_struct *vma)
503 {
504 	int ret;
505 
506 	ret = drm_gem_mmap_obj(obj, obj->size, vma);
507 	if (ret < 0)
508 		return ret;
509 
510 	return exynos_drm_gem_mmap_obj(obj, vma);
511 }
512