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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. | |
4c78513e DV |
64 | * @mmap: used to expose the backing storage to userspace. Note that the |
65 | * mapping needs to be coherent - if the exporter doesn't directly | |
66 | * support this, it needs to fake coherency by shooting down any ptes | |
67 | * when transitioning away from the cpu domain. | |
12c4727e SS |
68 | * @vmap: [optional] creates a virtual mapping for the buffer into kernel |
69 | * address space. Same restrictions as for vmap and friends apply. | |
70 | * @vunmap: [optional] unmaps a vmap from the buffer | |
d15bd7ee SS |
71 | */ |
72 | struct dma_buf_ops { | |
73 | int (*attach)(struct dma_buf *, struct device *, | |
74 | struct dma_buf_attachment *); | |
75 | ||
76 | void (*detach)(struct dma_buf *, struct dma_buf_attachment *); | |
77 | ||
78 | /* For {map,unmap}_dma_buf below, any specific buffer attributes | |
79 | * required should get added to device_dma_parameters accessible | |
80 | * via dev->dma_params. | |
81 | */ | |
82 | struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *, | |
83 | enum dma_data_direction); | |
84 | void (*unmap_dma_buf)(struct dma_buf_attachment *, | |
33ea2dcb SS |
85 | struct sg_table *, |
86 | enum dma_data_direction); | |
d15bd7ee SS |
87 | /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY |
88 | * if the call would block. | |
89 | */ | |
90 | ||
91 | /* after final dma_buf_put() */ | |
92 | void (*release)(struct dma_buf *); | |
93 | ||
fc13020e DV |
94 | int (*begin_cpu_access)(struct dma_buf *, size_t, size_t, |
95 | enum dma_data_direction); | |
96 | void (*end_cpu_access)(struct dma_buf *, size_t, size_t, | |
97 | enum dma_data_direction); | |
98 | void *(*kmap_atomic)(struct dma_buf *, unsigned long); | |
99 | void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *); | |
100 | void *(*kmap)(struct dma_buf *, unsigned long); | |
101 | void (*kunmap)(struct dma_buf *, unsigned long, void *); | |
4c78513e DV |
102 | |
103 | int (*mmap)(struct dma_buf *, struct vm_area_struct *vma); | |
98f86c9e DA |
104 | |
105 | void *(*vmap)(struct dma_buf *); | |
106 | void (*vunmap)(struct dma_buf *, void *vaddr); | |
d15bd7ee SS |
107 | }; |
108 | ||
109 | /** | |
110 | * struct dma_buf - shared buffer object | |
111 | * @size: size of the buffer | |
112 | * @file: file pointer used for sharing buffers across, and for refcounting. | |
113 | * @attachments: list of dma_buf_attachment that denotes all devices attached. | |
114 | * @ops: dma_buf_ops associated with this buffer object. | |
115 | * @priv: exporter specific private data for this buffer object. | |
116 | */ | |
117 | struct dma_buf { | |
118 | size_t size; | |
119 | struct file *file; | |
120 | struct list_head attachments; | |
121 | const struct dma_buf_ops *ops; | |
6b607e3a | 122 | /* mutex to serialize list manipulation and attach/detach */ |
d15bd7ee SS |
123 | struct mutex lock; |
124 | void *priv; | |
125 | }; | |
126 | ||
127 | /** | |
128 | * struct dma_buf_attachment - holds device-buffer attachment data | |
129 | * @dmabuf: buffer for this attachment. | |
130 | * @dev: device attached to the buffer. | |
131 | * @node: list of dma_buf_attachment. | |
132 | * @priv: exporter specific attachment data. | |
133 | * | |
134 | * This structure holds the attachment information between the dma_buf buffer | |
135 | * and its user device(s). The list contains one attachment struct per device | |
136 | * attached to the buffer. | |
137 | */ | |
138 | struct dma_buf_attachment { | |
139 | struct dma_buf *dmabuf; | |
140 | struct device *dev; | |
141 | struct list_head node; | |
142 | void *priv; | |
143 | }; | |
144 | ||
f9a24d1a RC |
145 | /** |
146 | * get_dma_buf - convenience wrapper for get_file. | |
147 | * @dmabuf: [in] pointer to dma_buf | |
148 | * | |
149 | * Increments the reference count on the dma-buf, needed in case of drivers | |
150 | * that either need to create additional references to the dmabuf on the | |
151 | * kernel side. For example, an exporter that needs to keep a dmabuf ptr | |
152 | * so that subsequent exports don't create a new dmabuf. | |
153 | */ | |
154 | static inline void get_dma_buf(struct dma_buf *dmabuf) | |
155 | { | |
156 | get_file(dmabuf->file); | |
157 | } | |
158 | ||
d15bd7ee SS |
159 | struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, |
160 | struct device *dev); | |
161 | void dma_buf_detach(struct dma_buf *dmabuf, | |
162 | struct dma_buf_attachment *dmabuf_attach); | |
5375764f LP |
163 | struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, |
164 | size_t size, int flags); | |
55c1c4ca | 165 | int dma_buf_fd(struct dma_buf *dmabuf, int flags); |
d15bd7ee SS |
166 | struct dma_buf *dma_buf_get(int fd); |
167 | void dma_buf_put(struct dma_buf *dmabuf); | |
168 | ||
169 | struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *, | |
170 | enum dma_data_direction); | |
33ea2dcb SS |
171 | void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *, |
172 | enum dma_data_direction); | |
fc13020e DV |
173 | int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len, |
174 | enum dma_data_direction dir); | |
175 | void dma_buf_end_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len, | |
176 | enum dma_data_direction dir); | |
177 | void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long); | |
178 | void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *); | |
179 | void *dma_buf_kmap(struct dma_buf *, unsigned long); | |
180 | void dma_buf_kunmap(struct dma_buf *, unsigned long, void *); | |
4c78513e DV |
181 | |
182 | int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *, | |
183 | unsigned long); | |
98f86c9e DA |
184 | void *dma_buf_vmap(struct dma_buf *); |
185 | void dma_buf_vunmap(struct dma_buf *, void *vaddr); | |
d15bd7ee SS |
186 | |
187 | #endif /* __DMA_BUF_H__ */ |