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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)
Tiago Vignatti831e9da2015-12-22 19:36:45 -020057 * respectively pin the object 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
Tiago Vignatti831e9da2015-12-22 19:36:45 -020096 int (*begin_cpu_access)(struct dma_buf *, enum dma_data_direction);
Chris Wilson18b862d2016-03-18 20:02:39 +000097 int (*end_cpu_access)(struct dma_buf *, enum dma_data_direction);
Daniel Vetterfc130202012-03-20 00:02:37 +010098 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.
Rob Clarke2082e32016-03-31 16:26:50 -0400115 * @lock: used internally to serialize list manipulation, attach/detach and vmap/unmap
116 * @vmapping_counter: used internally to refcnt the vmaps
117 * @vmap_ptr: the current vmap ptr if vmapping_counter > 0
Sumit Semwal78df9692013-03-22 18:22:16 +0530118 * @exp_name: name of the exporter; useful for debugging.
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530119 * @owner: pointer to exporter module; used for refcounting when exporter is a
120 * kernel module.
Sumit Semwalb89e3562013-04-04 11:44:37 +0530121 * @list_node: node for dma_buf accounting and debugging.
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530122 * @priv: exporter specific private data for this buffer object.
Maarten Lankhorst3aac4502014-07-01 12:57:26 +0200123 * @resv: reservation object linked to this dma-buf
Rob Clarke2082e32016-03-31 16:26:50 -0400124 * @poll: for userspace poll support
125 * @cb_excl: for userspace poll support
126 * @cb_shared: for userspace poll support
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530127 */
128struct dma_buf {
129 size_t size;
130 struct file *file;
131 struct list_head attachments;
132 const struct dma_buf_ops *ops;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530133 struct mutex lock;
Daniel Vetterf00b4da2012-12-20 14:14:23 +0100134 unsigned vmapping_counter;
135 void *vmap_ptr;
Sumit Semwal78df9692013-03-22 18:22:16 +0530136 const char *exp_name;
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530137 struct module *owner;
Sumit Semwalb89e3562013-04-04 11:44:37 +0530138 struct list_head list_node;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530139 void *priv;
Maarten Lankhorst3aac4502014-07-01 12:57:26 +0200140 struct reservation_object *resv;
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200141
142 /* poll support */
143 wait_queue_head_t poll;
144
145 struct dma_buf_poll_cb_t {
146 struct fence_cb cb;
147 wait_queue_head_t *poll;
148
149 unsigned long active;
150 } cb_excl, cb_shared;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530151};
152
153/**
154 * struct dma_buf_attachment - holds device-buffer attachment data
155 * @dmabuf: buffer for this attachment.
156 * @dev: device attached to the buffer.
157 * @node: list of dma_buf_attachment.
158 * @priv: exporter specific attachment data.
159 *
160 * This structure holds the attachment information between the dma_buf buffer
161 * and its user device(s). The list contains one attachment struct per device
162 * attached to the buffer.
163 */
164struct dma_buf_attachment {
165 struct dma_buf *dmabuf;
166 struct device *dev;
167 struct list_head node;
168 void *priv;
169};
170
Rob Clarkf9a24d12012-03-16 11:04:41 -0500171/**
Sumit Semwald8fbe342015-01-23 12:53:43 +0530172 * struct dma_buf_export_info - holds information needed to export a dma_buf
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530173 * @exp_name: name of the exporter - useful for debugging.
174 * @owner: pointer to exporter module - used for refcounting kernel module
Sumit Semwald8fbe342015-01-23 12:53:43 +0530175 * @ops: Attach allocator-defined dma buf ops to the new buffer
176 * @size: Size of the buffer
177 * @flags: mode flags for the file
178 * @resv: reservation-object, NULL to allocate default one
179 * @priv: Attach private data of allocator to this buffer
180 *
181 * This structure holds the information required to export the buffer. Used
182 * with dma_buf_export() only.
183 */
184struct dma_buf_export_info {
185 const char *exp_name;
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530186 struct module *owner;
Sumit Semwald8fbe342015-01-23 12:53:43 +0530187 const struct dma_buf_ops *ops;
188 size_t size;
189 int flags;
190 struct reservation_object *resv;
191 void *priv;
192};
193
194/**
195 * helper macro for exporters; zeros and fills in most common values
Rob Clarke2082e32016-03-31 16:26:50 -0400196 *
197 * @name: export-info name
Sumit Semwald8fbe342015-01-23 12:53:43 +0530198 */
Rob Clarke2082e32016-03-31 16:26:50 -0400199#define DEFINE_DMA_BUF_EXPORT_INFO(name) \
200 struct dma_buf_export_info name = { .exp_name = KBUILD_MODNAME, \
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530201 .owner = THIS_MODULE }
Sumit Semwald8fbe342015-01-23 12:53:43 +0530202
203/**
Rob Clarkf9a24d12012-03-16 11:04:41 -0500204 * get_dma_buf - convenience wrapper for get_file.
205 * @dmabuf: [in] pointer to dma_buf
206 *
207 * Increments the reference count on the dma-buf, needed in case of drivers
208 * that either need to create additional references to the dmabuf on the
209 * kernel side. For example, an exporter that needs to keep a dmabuf ptr
210 * so that subsequent exports don't create a new dmabuf.
211 */
212static inline void get_dma_buf(struct dma_buf *dmabuf)
213{
214 get_file(dmabuf->file);
215}
216
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530217struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
218 struct device *dev);
219void dma_buf_detach(struct dma_buf *dmabuf,
220 struct dma_buf_attachment *dmabuf_attach);
Sumit Semwal78df9692013-03-22 18:22:16 +0530221
Sumit Semwald8fbe342015-01-23 12:53:43 +0530222struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info);
Sumit Semwal78df9692013-03-22 18:22:16 +0530223
Dave Airlie55c1c4c2012-03-16 10:34:02 +0000224int dma_buf_fd(struct dma_buf *dmabuf, int flags);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530225struct dma_buf *dma_buf_get(int fd);
226void dma_buf_put(struct dma_buf *dmabuf);
227
228struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
229 enum dma_data_direction);
Sumit Semwal33ea2dc2012-01-27 15:09:27 +0530230void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *,
231 enum dma_data_direction);
Tiago Vignatti831e9da2015-12-22 19:36:45 -0200232int dma_buf_begin_cpu_access(struct dma_buf *dma_buf,
Daniel Vetterfc130202012-03-20 00:02:37 +0100233 enum dma_data_direction dir);
Chris Wilson18b862d2016-03-18 20:02:39 +0000234int dma_buf_end_cpu_access(struct dma_buf *dma_buf,
235 enum dma_data_direction dir);
Daniel Vetterfc130202012-03-20 00:02:37 +0100236void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long);
237void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *);
238void *dma_buf_kmap(struct dma_buf *, unsigned long);
239void dma_buf_kunmap(struct dma_buf *, unsigned long, void *);
Daniel Vetter4c785132012-04-24 14:38:52 +0530240
241int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
242 unsigned long);
Dave Airlie98f86c92012-05-20 12:33:56 +0530243void *dma_buf_vmap(struct dma_buf *);
244void dma_buf_vunmap(struct dma_buf *, void *vaddr);
Sumit Semwalb89e3562013-04-04 11:44:37 +0530245int dma_buf_debugfs_create_file(const char *name,
246 int (*write)(struct seq_file *));
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530247#endif /* __DMA_BUF_H__ */