tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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-mapping.h>
25
26#include <drm/drmP.h>
27#include <drm/drm.h>
28#include <drm/drm_gem_cma_helper.h>
29
30static unsigned int get_gem_mmap_offset(struct drm_gem_object *obj)
31{
32 return (unsigned int)obj->map_list.hash.key << PAGE_SHIFT;
33}
34
35static void drm_gem_cma_buf_destroy(struct drm_device *drm,
36 struct drm_gem_cma_object *cma_obj)
37{
38 dma_free_writecombine(drm->dev, cma_obj->base.size, cma_obj->vaddr,
39 cma_obj->paddr);
40}
41
42/*
43 * drm_gem_cma_create - allocate an object with the given size
44 *
45 * returns a struct drm_gem_cma_object* on success or ERR_PTR values
46 * on failure.
47 */
48struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
49 unsigned int size)
50{
51 struct drm_gem_cma_object *cma_obj;
52 struct drm_gem_object *gem_obj;
53 int ret;
54
55 size = round_up(size, PAGE_SIZE);
56
57 cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
58 if (!cma_obj)
59 return ERR_PTR(-ENOMEM);
60
61 cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size,
62 &cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN);
63 if (!cma_obj->vaddr) {
64 dev_err(drm->dev, "failed to allocate buffer with size %d\n", size);
65 ret = -ENOMEM;
66 goto err_dma_alloc;
67 }
68
69 gem_obj = &cma_obj->base;
70
71 ret = drm_gem_object_init(drm, gem_obj, size);
72 if (ret)
73 goto err_obj_init;
74
75 ret = drm_gem_create_mmap_offset(gem_obj);
76 if (ret)
77 goto err_create_mmap_offset;
78
79 return cma_obj;
80
81err_create_mmap_offset:
82 drm_gem_object_release(gem_obj);
83
84err_obj_init:
85 drm_gem_cma_buf_destroy(drm, cma_obj);
86
87err_dma_alloc:
88 kfree(cma_obj);
89
90 return ERR_PTR(ret);
91}
92EXPORT_SYMBOL_GPL(drm_gem_cma_create);
93
94/*
95 * drm_gem_cma_create_with_handle - allocate an object with the given
96 * size and create a gem handle on it
97 *
98 * returns a struct drm_gem_cma_object* on success or ERR_PTR values
99 * on failure.
100 */
101static struct drm_gem_cma_object *drm_gem_cma_create_with_handle(
102 struct drm_file *file_priv,
103 struct drm_device *drm, unsigned int size,
104 unsigned int *handle)
105{
106 struct drm_gem_cma_object *cma_obj;
107 struct drm_gem_object *gem_obj;
108 int ret;
109
110 cma_obj = drm_gem_cma_create(drm, size);
111 if (IS_ERR(cma_obj))
112 return cma_obj;
113
114 gem_obj = &cma_obj->base;
115
116 /*
117 * allocate a id of idr table where the obj is registered
118 * and handle has the id what user can see.
119 */
120 ret = drm_gem_handle_create(file_priv, gem_obj, handle);
121 if (ret)
122 goto err_handle_create;
123
124 /* drop reference from allocate - handle holds it now. */
125 drm_gem_object_unreference_unlocked(gem_obj);
126
127 return cma_obj;
128
129err_handle_create:
130 drm_gem_cma_free_object(gem_obj);
131
132 return ERR_PTR(ret);
133}
134
135/*
136 * drm_gem_cma_free_object - (struct drm_driver)->gem_free_object callback
137 * function
138 */
139void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
140{
141 struct drm_gem_cma_object *cma_obj;
142
143 if (gem_obj->map_list.map)
144 drm_gem_free_mmap_offset(gem_obj);
145
146 drm_gem_object_release(gem_obj);
147
148 cma_obj = to_drm_gem_cma_obj(gem_obj);
149
150 drm_gem_cma_buf_destroy(gem_obj->dev, cma_obj);
151
152 kfree(cma_obj);
153}
154EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
155
156/*
157 * drm_gem_cma_dumb_create - (struct drm_driver)->dumb_create callback
158 * function
159 *
160 * This aligns the pitch and size arguments to the minimum required. wrap
161 * this into your own function if you need bigger alignment.
162 */
163int drm_gem_cma_dumb_create(struct drm_file *file_priv,
164 struct drm_device *dev, struct drm_mode_create_dumb *args)
165{
166 struct drm_gem_cma_object *cma_obj;
167 int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
168
169 if (args->pitch < min_pitch)
170 args->pitch = min_pitch;
171
172 if (args->size < args->pitch * args->height)
173 args->size = args->pitch * args->height;
174
175 cma_obj = drm_gem_cma_create_with_handle(file_priv, dev,
176 args->size, &args->handle);
177 if (IS_ERR(cma_obj))
178 return PTR_ERR(cma_obj);
179
180 return 0;
181}
182EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
183
184/*
185 * drm_gem_cma_dumb_map_offset - (struct drm_driver)->dumb_map_offset callback
186 * function
187 */
188int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
189 struct drm_device *drm, uint32_t handle, uint64_t *offset)
190{
191 struct drm_gem_object *gem_obj;
192
193 mutex_lock(&drm->struct_mutex);
194
195 gem_obj = drm_gem_object_lookup(drm, file_priv, handle);
196 if (!gem_obj) {
197 dev_err(drm->dev, "failed to lookup gem object\n");
198 mutex_unlock(&drm->struct_mutex);
199 return -EINVAL;
200 }
201
202 *offset = get_gem_mmap_offset(gem_obj);
203
204 drm_gem_object_unreference(gem_obj);
205
206 mutex_unlock(&drm->struct_mutex);
207
208 return 0;
209}
210EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset);
211
212const struct vm_operations_struct drm_gem_cma_vm_ops = {
213 .open = drm_gem_vm_open,
214 .close = drm_gem_vm_close,
215};
216EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
217
218/*
219 * drm_gem_cma_mmap - (struct file_operation)->mmap callback function
220 */
221int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
222{
223 struct drm_gem_object *gem_obj;
224 struct drm_gem_cma_object *cma_obj;
225 int ret;
226
227 ret = drm_gem_mmap(filp, vma);
228 if (ret)
229 return ret;
230
231 gem_obj = vma->vm_private_data;
232 cma_obj = to_drm_gem_cma_obj(gem_obj);
233
234 ret = remap_pfn_range(vma, vma->vm_start, cma_obj->paddr >> PAGE_SHIFT,
235 vma->vm_end - vma->vm_start, vma->vm_page_prot);
236 if (ret)
237 drm_gem_vm_close(vma);
238
239 return ret;
240}
241EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
242
243/*
244 * drm_gem_cma_dumb_destroy - (struct drm_driver)->dumb_destroy callback function
245 */
246int drm_gem_cma_dumb_destroy(struct drm_file *file_priv,
247 struct drm_device *drm, unsigned int handle)
248{
249 return drm_gem_handle_delete(file_priv, handle);
250}
251EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_destroy);