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d15bd7ee SS |
1 | /* |
2 | * Header file for dma buffer sharing framework. | |
3 | * | |
4 | * Copyright(C) 2011 Linaro Limited. All rights reserved. | |
5 | * Author: Sumit Semwal <sumit.semwal@ti.com> | |
6 | * | |
7 | * Many thanks to linaro-mm-sig list, and specially | |
8 | * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and | |
9 | * Daniel Vetter <daniel@ffwll.ch> for their support in creation and | |
10 | * refining of this idea. | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify it | |
13 | * under the terms of the GNU General Public License version 2 as published by | |
14 | * the Free Software Foundation. | |
15 | * | |
16 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
17 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
18 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
19 | * more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License along with | |
22 | * this program. If not, see <http://www.gnu.org/licenses/>. | |
23 | */ | |
24 | #ifndef __DMA_BUF_H__ | |
25 | #define __DMA_BUF_H__ | |
26 | ||
27 | #include <linux/file.h> | |
28 | #include <linux/err.h> | |
d15bd7ee SS |
29 | #include <linux/scatterlist.h> |
30 | #include <linux/list.h> | |
31 | #include <linux/dma-mapping.h> | |
f9a24d1a | 32 | #include <linux/fs.h> |
d15bd7ee | 33 | |
313162d0 | 34 | struct device; |
d15bd7ee SS |
35 | struct dma_buf; |
36 | struct dma_buf_attachment; | |
37 | ||
38 | /** | |
39 | * struct dma_buf_ops - operations possible on struct dma_buf | |
40 | * @attach: [optional] allows different devices to 'attach' themselves to the | |
41 | * given buffer. It might return -EBUSY to signal that backing storage | |
42 | * is already allocated and incompatible with the requirements | |
43 | * of requesting device. | |
44 | * @detach: [optional] detach a given device from this buffer. | |
45 | * @map_dma_buf: returns list of scatter pages allocated, increases usecount | |
46 | * of the buffer. Requires atleast one attach to be called | |
47 | * before. Returned sg list should already be mapped into | |
48 | * _device_ address space. This call may sleep. May also return | |
49 | * -EINTR. Should return -EINVAL if attach hasn't been called yet. | |
50 | * @unmap_dma_buf: decreases usecount of buffer, might deallocate scatter | |
51 | * pages. | |
52 | * @release: release this buffer; to be called after the last dma_buf_put. | |
fc13020e DV |
53 | * @begin_cpu_access: [optional] called before cpu access to invalidate cpu |
54 | * caches and allocate backing storage (if not yet done) | |
55 | * respectively pin the objet into memory. | |
56 | * @end_cpu_access: [optional] called after cpu access to flush cashes. | |
57 | * @kmap_atomic: maps a page from the buffer into kernel address | |
58 | * space, users may not block until the subsequent unmap call. | |
59 | * This callback must not sleep. | |
60 | * @kunmap_atomic: [optional] unmaps a atomically mapped page from the buffer. | |
61 | * This Callback must not sleep. | |
62 | * @kmap: maps a page from the buffer into kernel address space. | |
63 | * @kunmap: [optional] unmaps a page from the buffer. | |
d15bd7ee SS |
64 | */ |
65 | struct dma_buf_ops { | |
66 | int (*attach)(struct dma_buf *, struct device *, | |
67 | struct dma_buf_attachment *); | |
68 | ||
69 | void (*detach)(struct dma_buf *, struct dma_buf_attachment *); | |
70 | ||
71 | /* For {map,unmap}_dma_buf below, any specific buffer attributes | |
72 | * required should get added to device_dma_parameters accessible | |
73 | * via dev->dma_params. | |
74 | */ | |
75 | struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *, | |
76 | enum dma_data_direction); | |
77 | void (*unmap_dma_buf)(struct dma_buf_attachment *, | |
33ea2dcb SS |
78 | struct sg_table *, |
79 | enum dma_data_direction); | |
d15bd7ee SS |
80 | /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY |
81 | * if the call would block. | |
82 | */ | |
83 | ||
84 | /* after final dma_buf_put() */ | |
85 | void (*release)(struct dma_buf *); | |
86 | ||
fc13020e DV |
87 | int (*begin_cpu_access)(struct dma_buf *, size_t, size_t, |
88 | enum dma_data_direction); | |
89 | void (*end_cpu_access)(struct dma_buf *, size_t, size_t, | |
90 | enum dma_data_direction); | |
91 | void *(*kmap_atomic)(struct dma_buf *, unsigned long); | |
92 | void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *); | |
93 | void *(*kmap)(struct dma_buf *, unsigned long); | |
94 | void (*kunmap)(struct dma_buf *, unsigned long, void *); | |
d15bd7ee SS |
95 | }; |
96 | ||
97 | /** | |
98 | * struct dma_buf - shared buffer object | |
99 | * @size: size of the buffer | |
100 | * @file: file pointer used for sharing buffers across, and for refcounting. | |
101 | * @attachments: list of dma_buf_attachment that denotes all devices attached. | |
102 | * @ops: dma_buf_ops associated with this buffer object. | |
103 | * @priv: exporter specific private data for this buffer object. | |
104 | */ | |
105 | struct dma_buf { | |
106 | size_t size; | |
107 | struct file *file; | |
108 | struct list_head attachments; | |
109 | const struct dma_buf_ops *ops; | |
6b607e3a | 110 | /* mutex to serialize list manipulation and attach/detach */ |
d15bd7ee SS |
111 | struct mutex lock; |
112 | void *priv; | |
113 | }; | |
114 | ||
115 | /** | |
116 | * struct dma_buf_attachment - holds device-buffer attachment data | |
117 | * @dmabuf: buffer for this attachment. | |
118 | * @dev: device attached to the buffer. | |
119 | * @node: list of dma_buf_attachment. | |
120 | * @priv: exporter specific attachment data. | |
121 | * | |
122 | * This structure holds the attachment information between the dma_buf buffer | |
123 | * and its user device(s). The list contains one attachment struct per device | |
124 | * attached to the buffer. | |
125 | */ | |
126 | struct dma_buf_attachment { | |
127 | struct dma_buf *dmabuf; | |
128 | struct device *dev; | |
129 | struct list_head node; | |
130 | void *priv; | |
131 | }; | |
132 | ||
f9a24d1a RC |
133 | /** |
134 | * get_dma_buf - convenience wrapper for get_file. | |
135 | * @dmabuf: [in] pointer to dma_buf | |
136 | * | |
137 | * Increments the reference count on the dma-buf, needed in case of drivers | |
138 | * that either need to create additional references to the dmabuf on the | |
139 | * kernel side. For example, an exporter that needs to keep a dmabuf ptr | |
140 | * so that subsequent exports don't create a new dmabuf. | |
141 | */ | |
142 | static inline void get_dma_buf(struct dma_buf *dmabuf) | |
143 | { | |
144 | get_file(dmabuf->file); | |
145 | } | |
146 | ||
d15bd7ee SS |
147 | #ifdef CONFIG_DMA_SHARED_BUFFER |
148 | struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, | |
149 | struct device *dev); | |
150 | void dma_buf_detach(struct dma_buf *dmabuf, | |
151 | struct dma_buf_attachment *dmabuf_attach); | |
5375764f LP |
152 | struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, |
153 | size_t size, int flags); | |
55c1c4ca | 154 | int dma_buf_fd(struct dma_buf *dmabuf, int flags); |
d15bd7ee SS |
155 | struct dma_buf *dma_buf_get(int fd); |
156 | void dma_buf_put(struct dma_buf *dmabuf); | |
157 | ||
158 | struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *, | |
159 | enum dma_data_direction); | |
33ea2dcb SS |
160 | void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *, |
161 | enum dma_data_direction); | |
fc13020e DV |
162 | int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len, |
163 | enum dma_data_direction dir); | |
164 | void dma_buf_end_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len, | |
165 | enum dma_data_direction dir); | |
166 | void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long); | |
167 | void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *); | |
168 | void *dma_buf_kmap(struct dma_buf *, unsigned long); | |
169 | void dma_buf_kunmap(struct dma_buf *, unsigned long, void *); | |
d15bd7ee SS |
170 | #else |
171 | ||
172 | static inline struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, | |
173 | struct device *dev) | |
174 | { | |
175 | return ERR_PTR(-ENODEV); | |
176 | } | |
177 | ||
178 | static inline void dma_buf_detach(struct dma_buf *dmabuf, | |
179 | struct dma_buf_attachment *dmabuf_attach) | |
180 | { | |
181 | return; | |
182 | } | |
183 | ||
184 | static inline struct dma_buf *dma_buf_export(void *priv, | |
5375764f LP |
185 | const struct dma_buf_ops *ops, |
186 | size_t size, int flags) | |
d15bd7ee SS |
187 | { |
188 | return ERR_PTR(-ENODEV); | |
189 | } | |
190 | ||
3e0b2a19 | 191 | static inline int dma_buf_fd(struct dma_buf *dmabuf, int flags) |
d15bd7ee SS |
192 | { |
193 | return -ENODEV; | |
194 | } | |
195 | ||
196 | static inline struct dma_buf *dma_buf_get(int fd) | |
197 | { | |
198 | return ERR_PTR(-ENODEV); | |
199 | } | |
200 | ||
201 | static inline void dma_buf_put(struct dma_buf *dmabuf) | |
202 | { | |
203 | return; | |
204 | } | |
205 | ||
206 | static inline struct sg_table *dma_buf_map_attachment( | |
207 | struct dma_buf_attachment *attach, enum dma_data_direction write) | |
208 | { | |
209 | return ERR_PTR(-ENODEV); | |
210 | } | |
211 | ||
212 | static inline void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, | |
33ea2dcb | 213 | struct sg_table *sg, enum dma_data_direction dir) |
d15bd7ee SS |
214 | { |
215 | return; | |
216 | } | |
217 | ||
3e0b2a19 SS |
218 | static inline int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
219 | size_t start, size_t len, | |
220 | enum dma_data_direction dir) | |
fc13020e DV |
221 | { |
222 | return -ENODEV; | |
223 | } | |
224 | ||
3e0b2a19 SS |
225 | static inline void dma_buf_end_cpu_access(struct dma_buf *dmabuf, |
226 | size_t start, size_t len, | |
227 | enum dma_data_direction dir) | |
fc13020e DV |
228 | { |
229 | } | |
230 | ||
3e0b2a19 SS |
231 | static inline void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, |
232 | unsigned long pnum) | |
fc13020e DV |
233 | { |
234 | return NULL; | |
235 | } | |
236 | ||
3e0b2a19 SS |
237 | static inline void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, |
238 | unsigned long pnum, void *vaddr) | |
fc13020e DV |
239 | { |
240 | } | |
241 | ||
3e0b2a19 | 242 | static inline void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long pnum) |
fc13020e DV |
243 | { |
244 | return NULL; | |
245 | } | |
246 | ||
3e0b2a19 SS |
247 | static inline void dma_buf_kunmap(struct dma_buf *dmabuf, |
248 | unsigned long pnum, void *vaddr) | |
fc13020e DV |
249 | { |
250 | } | |
d15bd7ee SS |
251 | #endif /* CONFIG_DMA_SHARED_BUFFER */ |
252 | ||
253 | #endif /* __DMA_BUF_H__ */ |