2 * Header file for dma buffer sharing framework.
4 * Copyright(C) 2011 Linaro Limited. All rights reserved.
5 * Author: Sumit Semwal <sumit.semwal@ti.com>
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.
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.
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
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/>.
27 #include <linux/file.h>
28 #include <linux/err.h>
29 #include <linux/scatterlist.h>
30 #include <linux/list.h>
31 #include <linux/dma-mapping.h>
33 #ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
34 #include <linux/kds.h>
35 #include <linux/wait.h>
40 struct dma_buf_attachment;
43 * struct dma_buf_ops - operations possible on struct dma_buf
44 * @attach: [optional] allows different devices to 'attach' themselves to the
45 * given buffer. It might return -EBUSY to signal that backing storage
46 * is already allocated and incompatible with the requirements
47 * of requesting device.
48 * @detach: [optional] detach a given device from this buffer.
49 * @map_dma_buf: returns list of scatter pages allocated, increases usecount
50 * of the buffer. Requires atleast one attach to be called
51 * before. Returned sg list should already be mapped into
52 * _device_ address space. This call may sleep. May also return
53 * -EINTR. Should return -EINVAL if attach hasn't been called yet.
54 * @unmap_dma_buf: decreases usecount of buffer, might deallocate scatter
56 * @release: release this buffer; to be called after the last dma_buf_put.
57 * @begin_cpu_access: [optional] called before cpu access to invalidate cpu
58 * caches and allocate backing storage (if not yet done)
59 * respectively pin the objet into memory.
60 * @end_cpu_access: [optional] called after cpu access to flush cashes.
61 * @kmap_atomic: maps a page from the buffer into kernel address
62 * space, users may not block until the subsequent unmap call.
63 * This callback must not sleep.
64 * @kunmap_atomic: [optional] unmaps a atomically mapped page from the buffer.
65 * This Callback must not sleep.
66 * @kmap: maps a page from the buffer into kernel address space.
67 * @kunmap: [optional] unmaps a page from the buffer.
68 * @mmap: used to expose the backing storage to userspace. Note that the
69 * mapping needs to be coherent - if the exporter doesn't directly
70 * support this, it needs to fake coherency by shooting down any ptes
71 * when transitioning away from the cpu domain.
72 * @vmap: [optional] creates a virtual mapping for the buffer into kernel
73 * address space. Same restrictions as for vmap and friends apply.
74 * @vunmap: [optional] unmaps a vmap from the buffer
77 int (*attach)(struct dma_buf *, struct device *,
78 struct dma_buf_attachment *);
80 void (*detach)(struct dma_buf *, struct dma_buf_attachment *);
82 /* For {map,unmap}_dma_buf below, any specific buffer attributes
83 * required should get added to device_dma_parameters accessible
84 * via dev->dma_params.
86 struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *,
87 enum dma_data_direction);
88 void (*unmap_dma_buf)(struct dma_buf_attachment *,
90 enum dma_data_direction);
91 /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY
92 * if the call would block.
95 /* after final dma_buf_put() */
96 void (*release)(struct dma_buf *);
98 int (*begin_cpu_access)(struct dma_buf *, size_t, size_t,
99 enum dma_data_direction);
100 void (*end_cpu_access)(struct dma_buf *, size_t, size_t,
101 enum dma_data_direction);
102 void *(*kmap_atomic)(struct dma_buf *, unsigned long);
103 void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *);
104 void *(*kmap)(struct dma_buf *, unsigned long);
105 void (*kunmap)(struct dma_buf *, unsigned long, void *);
107 int (*mmap)(struct dma_buf *, struct vm_area_struct *vma);
109 void *(*vmap)(struct dma_buf *);
110 void (*vunmap)(struct dma_buf *, void *vaddr);
114 * struct dma_buf - shared buffer object
115 * @size: size of the buffer
116 * @file: file pointer used for sharing buffers across, and for refcounting.
117 * @attachments: list of dma_buf_attachment that denotes all devices attached.
118 * @ops: dma_buf_ops associated with this buffer object.
119 * @priv: exporter specific private data for this buffer object.
124 struct list_head attachments;
125 const struct dma_buf_ops *ops;
126 /* mutex to serialize list manipulation and attach/detach */
128 #ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
129 struct kds_resource kds;
130 wait_queue_head_t wq_exclusive;
131 wait_queue_head_t wq_shared;
132 struct kds_callback kds_cb;
138 * struct dma_buf_attachment - holds device-buffer attachment data
139 * @dmabuf: buffer for this attachment.
140 * @dev: device attached to the buffer.
141 * @node: list of dma_buf_attachment.
142 * @priv: exporter specific attachment data.
144 * This structure holds the attachment information between the dma_buf buffer
145 * and its user device(s). The list contains one attachment struct per device
146 * attached to the buffer.
148 struct dma_buf_attachment {
149 struct dma_buf *dmabuf;
151 struct list_head node;
156 * get_dma_buf - convenience wrapper for get_file.
157 * @dmabuf: [in] pointer to dma_buf
159 * Increments the reference count on the dma-buf, needed in case of drivers
160 * that either need to create additional references to the dmabuf on the
161 * kernel side. For example, an exporter that needs to keep a dmabuf ptr
162 * so that subsequent exports don't create a new dmabuf.
164 static inline void get_dma_buf(struct dma_buf *dmabuf)
166 get_file(dmabuf->file);
169 #ifdef CONFIG_DMA_SHARED_BUFFER_USES_KDS
171 * get_dma_buf_kds_resource - get a KDS resource for this dma-buf
172 * @dmabuf: [in] pointer to dma_buf
174 * Returns a KDS resource that represents the dma-buf. This should be used by
175 * drivers to synchronize access to the buffer. Note that the caller should
176 * ensure that a reference to the dma-buf exists from the call to
177 * kds_async_wait until kds_resource_set_release is called.
179 static inline struct kds_resource *
180 get_dma_buf_kds_resource(struct dma_buf *dmabuf)
186 #ifdef CONFIG_DMA_SHARED_BUFFER
187 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
189 void dma_buf_detach(struct dma_buf *dmabuf,
190 struct dma_buf_attachment *dmabuf_attach);
191 struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
192 size_t size, int flags);
193 int dma_buf_fd(struct dma_buf *dmabuf, int flags);
194 struct dma_buf *dma_buf_get(int fd);
195 void dma_buf_put(struct dma_buf *dmabuf);
197 struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
198 enum dma_data_direction);
199 void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *,
200 enum dma_data_direction);
201 int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
202 enum dma_data_direction dir);
203 void dma_buf_end_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
204 enum dma_data_direction dir);
205 void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long);
206 void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *);
207 void *dma_buf_kmap(struct dma_buf *, unsigned long);
208 void dma_buf_kunmap(struct dma_buf *, unsigned long, void *);
210 int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
212 void *dma_buf_vmap(struct dma_buf *);
213 void dma_buf_vunmap(struct dma_buf *, void *vaddr);
216 static inline struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
219 return ERR_PTR(-ENODEV);
222 static inline void dma_buf_detach(struct dma_buf *dmabuf,
223 struct dma_buf_attachment *dmabuf_attach)
228 static inline struct dma_buf *dma_buf_export(void *priv,
229 const struct dma_buf_ops *ops,
230 size_t size, int flags)
232 return ERR_PTR(-ENODEV);
235 static inline int dma_buf_fd(struct dma_buf *dmabuf, int flags)
240 static inline struct dma_buf *dma_buf_get(int fd)
242 return ERR_PTR(-ENODEV);
245 static inline void dma_buf_put(struct dma_buf *dmabuf)
250 static inline struct sg_table *dma_buf_map_attachment(
251 struct dma_buf_attachment *attach, enum dma_data_direction write)
253 return ERR_PTR(-ENODEV);
256 static inline void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
257 struct sg_table *sg, enum dma_data_direction dir)
262 static inline int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
263 size_t start, size_t len,
264 enum dma_data_direction dir)
269 static inline void dma_buf_end_cpu_access(struct dma_buf *dmabuf,
270 size_t start, size_t len,
271 enum dma_data_direction dir)
275 static inline void *dma_buf_kmap_atomic(struct dma_buf *dmabuf,
281 static inline void dma_buf_kunmap_atomic(struct dma_buf *dmabuf,
282 unsigned long pnum, void *vaddr)
286 static inline void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long pnum)
291 static inline void dma_buf_kunmap(struct dma_buf *dmabuf,
292 unsigned long pnum, void *vaddr)
296 static inline int dma_buf_mmap(struct dma_buf *dmabuf,
297 struct vm_area_struct *vma,
303 static inline void *dma_buf_vmap(struct dma_buf *dmabuf)
308 static inline void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
311 #endif /* CONFIG_DMA_SHARED_BUFFER */
313 #endif /* __DMA_BUF_H__ */