Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 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> |
| 29 | #include <linux/device.h> |
| 30 | #include <linux/scatterlist.h> |
| 31 | #include <linux/list.h> |
| 32 | #include <linux/dma-mapping.h> |
Rob Clark | f9a24d1 | 2012-03-16 11:04:41 -0500 | [diff] [blame] | 33 | #include <linux/fs.h> |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 34 | |
| 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. |
Daniel Vetter | fc13020 | 2012-03-20 00:02:37 +0100 | [diff] [blame] | 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. |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 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 *, |
Sumit Semwal | 33ea2dc | 2012-01-27 15:09:27 +0530 | [diff] [blame] | 78 | struct sg_table *, |
| 79 | enum dma_data_direction); |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 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 | |
Daniel Vetter | fc13020 | 2012-03-20 00:02:37 +0100 | [diff] [blame] | 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 *); |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 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; |
Daniel Vetter | 6b607e3 | 2012-03-19 00:34:25 +0100 | [diff] [blame] | 110 | /* mutex to serialize list manipulation and attach/detach */ |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 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 | |
Rob Clark | f9a24d1 | 2012-03-16 11:04:41 -0500 | [diff] [blame] | 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 | |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 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); |
Laurent Pinchart | 5375764 | 2012-01-26 12:27:22 +0100 | [diff] [blame] | 152 | struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, |
| 153 | size_t size, int flags); |
Dave Airlie | 55c1c4c | 2012-03-16 10:34:02 +0000 | [diff] [blame] | 154 | int dma_buf_fd(struct dma_buf *dmabuf, int flags); |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 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); |
Sumit Semwal | 33ea2dc | 2012-01-27 15:09:27 +0530 | [diff] [blame] | 160 | void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *, |
| 161 | enum dma_data_direction); |
Daniel Vetter | fc13020 | 2012-03-20 00:02:37 +0100 | [diff] [blame] | 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 *); |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 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, |
Laurent Pinchart | 5375764 | 2012-01-26 12:27:22 +0100 | [diff] [blame] | 185 | const struct dma_buf_ops *ops, |
| 186 | size_t size, int flags) |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 187 | { |
| 188 | return ERR_PTR(-ENODEV); |
| 189 | } |
| 190 | |
Sumit Semwal | 3e0b2a1 | 2012-03-26 11:29:19 +0530 | [diff] [blame^] | 191 | static inline int dma_buf_fd(struct dma_buf *dmabuf, int flags) |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 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, |
Sumit Semwal | 33ea2dc | 2012-01-27 15:09:27 +0530 | [diff] [blame] | 213 | struct sg_table *sg, enum dma_data_direction dir) |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 214 | { |
| 215 | return; |
| 216 | } |
| 217 | |
Sumit Semwal | 3e0b2a1 | 2012-03-26 11:29:19 +0530 | [diff] [blame^] | 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) |
Daniel Vetter | fc13020 | 2012-03-20 00:02:37 +0100 | [diff] [blame] | 221 | { |
| 222 | return -ENODEV; |
| 223 | } |
| 224 | |
Sumit Semwal | 3e0b2a1 | 2012-03-26 11:29:19 +0530 | [diff] [blame^] | 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) |
Daniel Vetter | fc13020 | 2012-03-20 00:02:37 +0100 | [diff] [blame] | 228 | { |
| 229 | } |
| 230 | |
Sumit Semwal | 3e0b2a1 | 2012-03-26 11:29:19 +0530 | [diff] [blame^] | 231 | static inline void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, |
| 232 | unsigned long pnum) |
Daniel Vetter | fc13020 | 2012-03-20 00:02:37 +0100 | [diff] [blame] | 233 | { |
| 234 | return NULL; |
| 235 | } |
| 236 | |
Sumit Semwal | 3e0b2a1 | 2012-03-26 11:29:19 +0530 | [diff] [blame^] | 237 | static inline void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, |
| 238 | unsigned long pnum, void *vaddr) |
Daniel Vetter | fc13020 | 2012-03-20 00:02:37 +0100 | [diff] [blame] | 239 | { |
| 240 | } |
| 241 | |
Sumit Semwal | 3e0b2a1 | 2012-03-26 11:29:19 +0530 | [diff] [blame^] | 242 | static inline void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long pnum) |
Daniel Vetter | fc13020 | 2012-03-20 00:02:37 +0100 | [diff] [blame] | 243 | { |
| 244 | return NULL; |
| 245 | } |
| 246 | |
Sumit Semwal | 3e0b2a1 | 2012-03-26 11:29:19 +0530 | [diff] [blame^] | 247 | static inline void dma_buf_kunmap(struct dma_buf *dmabuf, |
| 248 | unsigned long pnum, void *vaddr) |
Daniel Vetter | fc13020 | 2012-03-20 00:02:37 +0100 | [diff] [blame] | 249 | { |
| 250 | } |
Sumit Semwal | d15bd7e | 2011-12-26 14:53:15 +0530 | [diff] [blame] | 251 | #endif /* CONFIG_DMA_SHARED_BUFFER */ |
| 252 | |
| 253 | #endif /* __DMA_BUF_H__ */ |