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Sumit Semwald15bd7e2011-12-26 14:53:15 +05301/*
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>
Sumit Semwald15bd7e2011-12-26 14:53:15 +053029#include <linux/scatterlist.h>
30#include <linux/list.h>
31#include <linux/dma-mapping.h>
Rob Clarkf9a24d12012-03-16 11:04:41 -050032#include <linux/fs.h>
Sumit Semwald15bd7e2011-12-26 14:53:15 +053033
Paul Gortmaker313162d2012-01-30 11:46:54 -050034struct device;
Sumit Semwald15bd7e2011-12-26 14:53:15 +053035struct dma_buf;
36struct 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 Vetterfc130202012-03-20 00:02:37 +010053 * @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.
Daniel Vetter4c785132012-04-24 14:38:52 +053064 * @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.
Sumit Semwal12c47272012-05-23 15:27:40 +053068 * @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
Sumit Semwald15bd7e2011-12-26 14:53:15 +053071 */
72struct 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 *,
Sumit Semwal33ea2dc2012-01-27 15:09:27 +053085 struct sg_table *,
86 enum dma_data_direction);
Sumit Semwald15bd7e2011-12-26 14:53:15 +053087 /* 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
Daniel Vetterfc130202012-03-20 00:02:37 +010094 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 *);
Daniel Vetter4c785132012-04-24 14:38:52 +0530102
103 int (*mmap)(struct dma_buf *, struct vm_area_struct *vma);
Dave Airlie98f86c92012-05-20 12:33:56 +0530104
105 void *(*vmap)(struct dma_buf *);
106 void (*vunmap)(struct dma_buf *, void *vaddr);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530107};
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 */
117struct dma_buf {
118 size_t size;
119 struct file *file;
120 struct list_head attachments;
121 const struct dma_buf_ops *ops;
Daniel Vetter6b607e32012-03-19 00:34:25 +0100122 /* mutex to serialize list manipulation and attach/detach */
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530123 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 */
138struct dma_buf_attachment {
139 struct dma_buf *dmabuf;
140 struct device *dev;
141 struct list_head node;
142 void *priv;
143};
144
Rob Clarkf9a24d12012-03-16 11:04:41 -0500145/**
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 */
154static inline void get_dma_buf(struct dma_buf *dmabuf)
155{
156 get_file(dmabuf->file);
157}
158
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530159#ifdef CONFIG_DMA_SHARED_BUFFER
160struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
161 struct device *dev);
162void dma_buf_detach(struct dma_buf *dmabuf,
163 struct dma_buf_attachment *dmabuf_attach);
Laurent Pinchart53757642012-01-26 12:27:22 +0100164struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
165 size_t size, int flags);
Dave Airlie55c1c4c2012-03-16 10:34:02 +0000166int dma_buf_fd(struct dma_buf *dmabuf, int flags);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530167struct dma_buf *dma_buf_get(int fd);
168void dma_buf_put(struct dma_buf *dmabuf);
169
170struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
171 enum dma_data_direction);
Sumit Semwal33ea2dc2012-01-27 15:09:27 +0530172void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *,
173 enum dma_data_direction);
Daniel Vetterfc130202012-03-20 00:02:37 +0100174int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
175 enum dma_data_direction dir);
176void dma_buf_end_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
177 enum dma_data_direction dir);
178void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long);
179void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *);
180void *dma_buf_kmap(struct dma_buf *, unsigned long);
181void dma_buf_kunmap(struct dma_buf *, unsigned long, void *);
Daniel Vetter4c785132012-04-24 14:38:52 +0530182
183int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
184 unsigned long);
Dave Airlie98f86c92012-05-20 12:33:56 +0530185void *dma_buf_vmap(struct dma_buf *);
186void dma_buf_vunmap(struct dma_buf *, void *vaddr);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530187#else
188
189static inline struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
190 struct device *dev)
191{
192 return ERR_PTR(-ENODEV);
193}
194
195static inline void dma_buf_detach(struct dma_buf *dmabuf,
196 struct dma_buf_attachment *dmabuf_attach)
197{
198 return;
199}
200
201static inline struct dma_buf *dma_buf_export(void *priv,
Laurent Pinchart53757642012-01-26 12:27:22 +0100202 const struct dma_buf_ops *ops,
203 size_t size, int flags)
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530204{
205 return ERR_PTR(-ENODEV);
206}
207
Sumit Semwal3e0b2a12012-03-26 11:29:19 +0530208static inline int dma_buf_fd(struct dma_buf *dmabuf, int flags)
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530209{
210 return -ENODEV;
211}
212
213static inline struct dma_buf *dma_buf_get(int fd)
214{
215 return ERR_PTR(-ENODEV);
216}
217
218static inline void dma_buf_put(struct dma_buf *dmabuf)
219{
220 return;
221}
222
223static inline struct sg_table *dma_buf_map_attachment(
224 struct dma_buf_attachment *attach, enum dma_data_direction write)
225{
226 return ERR_PTR(-ENODEV);
227}
228
229static inline void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
Sumit Semwal33ea2dc2012-01-27 15:09:27 +0530230 struct sg_table *sg, enum dma_data_direction dir)
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530231{
232 return;
233}
234
Sumit Semwal3e0b2a12012-03-26 11:29:19 +0530235static inline int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
236 size_t start, size_t len,
237 enum dma_data_direction dir)
Daniel Vetterfc130202012-03-20 00:02:37 +0100238{
239 return -ENODEV;
240}
241
Sumit Semwal3e0b2a12012-03-26 11:29:19 +0530242static inline void dma_buf_end_cpu_access(struct dma_buf *dmabuf,
243 size_t start, size_t len,
244 enum dma_data_direction dir)
Daniel Vetterfc130202012-03-20 00:02:37 +0100245{
246}
247
Sumit Semwal3e0b2a12012-03-26 11:29:19 +0530248static inline void *dma_buf_kmap_atomic(struct dma_buf *dmabuf,
249 unsigned long pnum)
Daniel Vetterfc130202012-03-20 00:02:37 +0100250{
251 return NULL;
252}
253
Sumit Semwal3e0b2a12012-03-26 11:29:19 +0530254static inline void dma_buf_kunmap_atomic(struct dma_buf *dmabuf,
255 unsigned long pnum, void *vaddr)
Daniel Vetterfc130202012-03-20 00:02:37 +0100256{
257}
258
Sumit Semwal3e0b2a12012-03-26 11:29:19 +0530259static inline void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long pnum)
Daniel Vetterfc130202012-03-20 00:02:37 +0100260{
261 return NULL;
262}
263
Sumit Semwal3e0b2a12012-03-26 11:29:19 +0530264static inline void dma_buf_kunmap(struct dma_buf *dmabuf,
265 unsigned long pnum, void *vaddr)
Daniel Vetterfc130202012-03-20 00:02:37 +0100266{
267}
Daniel Vetter4c785132012-04-24 14:38:52 +0530268
269static inline int dma_buf_mmap(struct dma_buf *dmabuf,
270 struct vm_area_struct *vma,
271 unsigned long pgoff)
272{
273 return -ENODEV;
274}
Dave Airlie98f86c92012-05-20 12:33:56 +0530275
276static inline void *dma_buf_vmap(struct dma_buf *dmabuf)
277{
278 return NULL;
279}
280
281static inline void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
282{
283}
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530284#endif /* CONFIG_DMA_SHARED_BUFFER */
285
286#endif /* __DMA_BUF_H__ */