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>
36 struct dma_buf_attachment
;
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
52 * @release: release this buffer; to be called after the last dma_buf_put.
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.
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.
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
73 int (*attach
)(struct dma_buf
*, struct device
*,
74 struct dma_buf_attachment
*);
76 void (*detach
)(struct dma_buf
*, struct dma_buf_attachment
*);
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.
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
*,
86 enum dma_data_direction
);
87 /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY
88 * if the call would block.
91 /* after final dma_buf_put() */
92 void (*release
)(struct dma_buf
*);
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 *);
103 int (*mmap
)(struct dma_buf
*, struct vm_area_struct
*vma
);
105 void *(*vmap
)(struct dma_buf
*);
106 void (*vunmap
)(struct dma_buf
*, void *vaddr
);
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.
120 struct list_head attachments
;
121 const struct dma_buf_ops
*ops
;
122 /* mutex to serialize list manipulation and attach/detach */
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.
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.
138 struct dma_buf_attachment
{
139 struct dma_buf
*dmabuf
;
141 struct list_head node
;
146 * get_dma_buf - convenience wrapper for get_file.
147 * @dmabuf: [in] pointer to dma_buf
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.
154 static inline void get_dma_buf(struct dma_buf
*dmabuf
)
156 get_file(dmabuf
->file
);
159 struct dma_buf_attachment
*dma_buf_attach(struct dma_buf
*dmabuf
,
161 void dma_buf_detach(struct dma_buf
*dmabuf
,
162 struct dma_buf_attachment
*dmabuf_attach
);
163 struct dma_buf
*dma_buf_export(void *priv
, const struct dma_buf_ops
*ops
,
164 size_t size
, int flags
);
165 int dma_buf_fd(struct dma_buf
*dmabuf
, int flags
);
166 struct dma_buf
*dma_buf_get(int fd
);
167 void dma_buf_put(struct dma_buf
*dmabuf
);
169 struct sg_table
*dma_buf_map_attachment(struct dma_buf_attachment
*,
170 enum dma_data_direction
);
171 void dma_buf_unmap_attachment(struct dma_buf_attachment
*, struct sg_table
*,
172 enum dma_data_direction
);
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 *);
182 int dma_buf_mmap(struct dma_buf
*, struct vm_area_struct
*,
184 void *dma_buf_vmap(struct dma_buf
*);
185 void dma_buf_vunmap(struct dma_buf
*, void *vaddr
);
187 #endif /* __DMA_BUF_H__ */
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