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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>
Maarten Lankhorst9b495a52014-07-01 12:57:43 +020033#include <linux/fence.h>
34#include <linux/wait.h>
Sumit Semwald15bd7e2011-12-26 14:53:15 +053035
Paul Gortmaker313162d2012-01-30 11:46:54 -050036struct device;
Sumit Semwald15bd7e2011-12-26 14:53:15 +053037struct dma_buf;
38struct dma_buf_attachment;
39
40/**
41 * struct dma_buf_ops - operations possible on struct dma_buf
42 * @attach: [optional] allows different devices to 'attach' themselves to the
43 * given buffer. It might return -EBUSY to signal that backing storage
44 * is already allocated and incompatible with the requirements
45 * of requesting device.
46 * @detach: [optional] detach a given device from this buffer.
47 * @map_dma_buf: returns list of scatter pages allocated, increases usecount
48 * of the buffer. Requires atleast one attach to be called
49 * before. Returned sg list should already be mapped into
50 * _device_ address space. This call may sleep. May also return
51 * -EINTR. Should return -EINVAL if attach hasn't been called yet.
52 * @unmap_dma_buf: decreases usecount of buffer, might deallocate scatter
53 * pages.
54 * @release: release this buffer; to be called after the last dma_buf_put.
Daniel Vetterfc130202012-03-20 00:02:37 +010055 * @begin_cpu_access: [optional] called before cpu access to invalidate cpu
56 * caches and allocate backing storage (if not yet done)
57 * respectively pin the objet into memory.
Masanari Iida8a168ca2012-12-29 02:00:09 +090058 * @end_cpu_access: [optional] called after cpu access to flush caches.
Daniel Vetterfc130202012-03-20 00:02:37 +010059 * @kmap_atomic: maps a page from the buffer into kernel address
60 * space, users may not block until the subsequent unmap call.
61 * This callback must not sleep.
62 * @kunmap_atomic: [optional] unmaps a atomically mapped page from the buffer.
63 * This Callback must not sleep.
64 * @kmap: maps a page from the buffer into kernel address space.
65 * @kunmap: [optional] unmaps a page from the buffer.
Daniel Vetter4c785132012-04-24 14:38:52 +053066 * @mmap: used to expose the backing storage to userspace. Note that the
67 * mapping needs to be coherent - if the exporter doesn't directly
68 * support this, it needs to fake coherency by shooting down any ptes
69 * when transitioning away from the cpu domain.
Sumit Semwal12c47272012-05-23 15:27:40 +053070 * @vmap: [optional] creates a virtual mapping for the buffer into kernel
71 * address space. Same restrictions as for vmap and friends apply.
72 * @vunmap: [optional] unmaps a vmap from the buffer
Sumit Semwald15bd7e2011-12-26 14:53:15 +053073 */
74struct dma_buf_ops {
75 int (*attach)(struct dma_buf *, struct device *,
76 struct dma_buf_attachment *);
77
78 void (*detach)(struct dma_buf *, struct dma_buf_attachment *);
79
80 /* For {map,unmap}_dma_buf below, any specific buffer attributes
81 * required should get added to device_dma_parameters accessible
82 * via dev->dma_params.
83 */
84 struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *,
85 enum dma_data_direction);
86 void (*unmap_dma_buf)(struct dma_buf_attachment *,
Sumit Semwal33ea2dc2012-01-27 15:09:27 +053087 struct sg_table *,
88 enum dma_data_direction);
Sumit Semwald15bd7e2011-12-26 14:53:15 +053089 /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY
90 * if the call would block.
91 */
92
93 /* after final dma_buf_put() */
94 void (*release)(struct dma_buf *);
95
Daniel Vetterfc130202012-03-20 00:02:37 +010096 int (*begin_cpu_access)(struct dma_buf *, size_t, size_t,
97 enum dma_data_direction);
98 void (*end_cpu_access)(struct dma_buf *, size_t, size_t,
99 enum dma_data_direction);
100 void *(*kmap_atomic)(struct dma_buf *, unsigned long);
101 void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *);
102 void *(*kmap)(struct dma_buf *, unsigned long);
103 void (*kunmap)(struct dma_buf *, unsigned long, void *);
Daniel Vetter4c785132012-04-24 14:38:52 +0530104
105 int (*mmap)(struct dma_buf *, struct vm_area_struct *vma);
Dave Airlie98f86c92012-05-20 12:33:56 +0530106
107 void *(*vmap)(struct dma_buf *);
108 void (*vunmap)(struct dma_buf *, void *vaddr);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530109};
110
111/**
112 * struct dma_buf - shared buffer object
113 * @size: size of the buffer
114 * @file: file pointer used for sharing buffers across, and for refcounting.
115 * @attachments: list of dma_buf_attachment that denotes all devices attached.
116 * @ops: dma_buf_ops associated with this buffer object.
Sumit Semwal78df9692013-03-22 18:22:16 +0530117 * @exp_name: name of the exporter; useful for debugging.
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530118 * @owner: pointer to exporter module; used for refcounting when exporter is a
119 * kernel module.
Sumit Semwalb89e3562013-04-04 11:44:37 +0530120 * @list_node: node for dma_buf accounting and debugging.
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530121 * @priv: exporter specific private data for this buffer object.
Maarten Lankhorst3aac4502014-07-01 12:57:26 +0200122 * @resv: reservation object linked to this dma-buf
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530123 */
124struct dma_buf {
125 size_t size;
126 struct file *file;
127 struct list_head attachments;
128 const struct dma_buf_ops *ops;
Daniel Vetterf00b4da2012-12-20 14:14:23 +0100129 /* mutex to serialize list manipulation, attach/detach and vmap/unmap */
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530130 struct mutex lock;
Daniel Vetterf00b4da2012-12-20 14:14:23 +0100131 unsigned vmapping_counter;
132 void *vmap_ptr;
Sumit Semwal78df9692013-03-22 18:22:16 +0530133 const char *exp_name;
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530134 struct module *owner;
Sumit Semwalb89e3562013-04-04 11:44:37 +0530135 struct list_head list_node;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530136 void *priv;
Maarten Lankhorst3aac4502014-07-01 12:57:26 +0200137 struct reservation_object *resv;
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200138
139 /* poll support */
140 wait_queue_head_t poll;
141
142 struct dma_buf_poll_cb_t {
143 struct fence_cb cb;
144 wait_queue_head_t *poll;
145
146 unsigned long active;
147 } cb_excl, cb_shared;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530148};
149
150/**
151 * struct dma_buf_attachment - holds device-buffer attachment data
152 * @dmabuf: buffer for this attachment.
153 * @dev: device attached to the buffer.
154 * @node: list of dma_buf_attachment.
155 * @priv: exporter specific attachment data.
156 *
157 * This structure holds the attachment information between the dma_buf buffer
158 * and its user device(s). The list contains one attachment struct per device
159 * attached to the buffer.
160 */
161struct dma_buf_attachment {
162 struct dma_buf *dmabuf;
163 struct device *dev;
164 struct list_head node;
165 void *priv;
166};
167
Rob Clarkf9a24d12012-03-16 11:04:41 -0500168/**
Sumit Semwald8fbe342015-01-23 12:53:43 +0530169 * struct dma_buf_export_info - holds information needed to export a dma_buf
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530170 * @exp_name: name of the exporter - useful for debugging.
171 * @owner: pointer to exporter module - used for refcounting kernel module
Sumit Semwald8fbe342015-01-23 12:53:43 +0530172 * @ops: Attach allocator-defined dma buf ops to the new buffer
173 * @size: Size of the buffer
174 * @flags: mode flags for the file
175 * @resv: reservation-object, NULL to allocate default one
176 * @priv: Attach private data of allocator to this buffer
177 *
178 * This structure holds the information required to export the buffer. Used
179 * with dma_buf_export() only.
180 */
181struct dma_buf_export_info {
182 const char *exp_name;
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530183 struct module *owner;
Sumit Semwald8fbe342015-01-23 12:53:43 +0530184 const struct dma_buf_ops *ops;
185 size_t size;
186 int flags;
187 struct reservation_object *resv;
188 void *priv;
189};
190
191/**
192 * helper macro for exporters; zeros and fills in most common values
193 */
194#define DEFINE_DMA_BUF_EXPORT_INFO(a) \
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530195 struct dma_buf_export_info a = { .exp_name = KBUILD_MODNAME, \
196 .owner = THIS_MODULE }
Sumit Semwald8fbe342015-01-23 12:53:43 +0530197
198/**
Rob Clarkf9a24d12012-03-16 11:04:41 -0500199 * get_dma_buf - convenience wrapper for get_file.
200 * @dmabuf: [in] pointer to dma_buf
201 *
202 * Increments the reference count on the dma-buf, needed in case of drivers
203 * that either need to create additional references to the dmabuf on the
204 * kernel side. For example, an exporter that needs to keep a dmabuf ptr
205 * so that subsequent exports don't create a new dmabuf.
206 */
207static inline void get_dma_buf(struct dma_buf *dmabuf)
208{
209 get_file(dmabuf->file);
210}
211
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530212struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
213 struct device *dev);
214void dma_buf_detach(struct dma_buf *dmabuf,
215 struct dma_buf_attachment *dmabuf_attach);
Sumit Semwal78df9692013-03-22 18:22:16 +0530216
Sumit Semwald8fbe342015-01-23 12:53:43 +0530217struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info);
Sumit Semwal78df9692013-03-22 18:22:16 +0530218
Dave Airlie55c1c4c2012-03-16 10:34:02 +0000219int dma_buf_fd(struct dma_buf *dmabuf, int flags);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530220struct dma_buf *dma_buf_get(int fd);
221void dma_buf_put(struct dma_buf *dmabuf);
222
223struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
224 enum dma_data_direction);
Sumit Semwal33ea2dc2012-01-27 15:09:27 +0530225void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *,
226 enum dma_data_direction);
Daniel Vetterfc130202012-03-20 00:02:37 +0100227int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
228 enum dma_data_direction dir);
229void dma_buf_end_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
230 enum dma_data_direction dir);
231void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long);
232void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *);
233void *dma_buf_kmap(struct dma_buf *, unsigned long);
234void dma_buf_kunmap(struct dma_buf *, unsigned long, void *);
Daniel Vetter4c785132012-04-24 14:38:52 +0530235
236int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
237 unsigned long);
Dave Airlie98f86c92012-05-20 12:33:56 +0530238void *dma_buf_vmap(struct dma_buf *);
239void dma_buf_vunmap(struct dma_buf *, void *vaddr);
Sumit Semwalb89e3562013-04-04 11:44:37 +0530240int dma_buf_debugfs_create_file(const char *name,
241 int (*write)(struct seq_file *));
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530242#endif /* __DMA_BUF_H__ */