1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * generic helper functions for handling video4linux capture buffers
4 *
5 * (c) 2007 Mauro Carvalho Chehab, <mchehab@kernel.org>
6 *
7 * Highly based on video-buf written originally by:
8 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
9 * (c) 2006 Mauro Carvalho Chehab, <mchehab@kernel.org>
10 * (c) 2006 Ted Walther and John Sokol
11 */
12
13 #ifndef _VIDEOBUF_CORE_H
14 #define _VIDEOBUF_CORE_H
15
16 #include <linux/poll.h>
17 #include <linux/videodev2.h>
18
19 #define UNSET (-1U)
20
21
22 struct videobuf_buffer;
23 struct videobuf_queue;
24
25 /* --------------------------------------------------------------------- */
26
27 /*
28 * A small set of helper functions to manage video4linux buffers.
29 *
30 * struct videobuf_buffer holds the data structures used by the helper
31 * functions, additionally some commonly used fields for v4l buffers
32 * (width, height, lists, waitqueue) are in there. That struct should
33 * be used as first element in the drivers buffer struct.
34 *
35 * about the mmap helpers (videobuf_mmap_*):
36 *
37 * The mmaper function allows to map any subset of contiguous buffers.
38 * This includes one mmap() call for all buffers (which the original
39 * video4linux API uses) as well as one mmap() for every single buffer
40 * (which v4l2 uses).
41 *
42 * If there is a valid mapping for a buffer, buffer->baddr/bsize holds
43 * userspace address + size which can be fed into the
44 * videobuf_dma_init_user function listed above.
45 *
46 */
47
48 struct videobuf_mapping {
49 unsigned int count;
50 struct videobuf_queue *q;
51 };
52
53 enum videobuf_state {
54 VIDEOBUF_NEEDS_INIT = 0,
55 VIDEOBUF_PREPARED = 1,
56 VIDEOBUF_QUEUED = 2,
57 VIDEOBUF_ACTIVE = 3,
58 VIDEOBUF_DONE = 4,
59 VIDEOBUF_ERROR = 5,
60 VIDEOBUF_IDLE = 6,
61 };
62
63 struct videobuf_buffer {
64 unsigned int i;
65 u32 magic;
66
67 /* info about the buffer */
68 unsigned int width;
69 unsigned int height;
70 unsigned int bytesperline; /* use only if != 0 */
71 unsigned long size;
72 enum v4l2_field field;
73 enum videobuf_state state;
74 struct list_head stream; /* QBUF/DQBUF list */
75
76 /* touched by irq handler */
77 struct list_head queue;
78 wait_queue_head_t done;
79 unsigned int field_count;
80 u64 ts;
81
82 /* Memory type */
83 enum v4l2_memory memory;
84
85 /* buffer size */
86 size_t bsize;
87
88 /* buffer offset (mmap + overlay) */
89 size_t boff;
90
91 /* buffer addr (userland ptr!) */
92 unsigned long baddr;
93
94 /* for mmap'ed buffers */
95 struct videobuf_mapping *map;
96
97 /* Private pointer to allow specific methods to store their data */
98 int privsize;
99 void *priv;
100 };
101
102 struct videobuf_queue_ops {
103 int (*buf_setup)(struct videobuf_queue *q,
104 unsigned int *count, unsigned int *size);
105 int (*buf_prepare)(struct videobuf_queue *q,
106 struct videobuf_buffer *vb,
107 enum v4l2_field field);
108 void (*buf_queue)(struct videobuf_queue *q,
109 struct videobuf_buffer *vb);
110 void (*buf_release)(struct videobuf_queue *q,
111 struct videobuf_buffer *vb);
112 };
113
114 #define MAGIC_QTYPE_OPS 0x12261003
115
116 /* Helper operations - device type dependent */
117 struct videobuf_qtype_ops {
118 u32 magic;
119
120 struct videobuf_buffer *(*alloc_vb)(size_t size);
121 void *(*vaddr) (struct videobuf_buffer *buf);
122 int (*iolock) (struct videobuf_queue *q,
123 struct videobuf_buffer *vb,
124 struct v4l2_framebuffer *fbuf);
125 int (*sync) (struct videobuf_queue *q,
126 struct videobuf_buffer *buf);
127 int (*mmap_mapper) (struct videobuf_queue *q,
128 struct videobuf_buffer *buf,
129 struct vm_area_struct *vma);
130 };
131
132 struct videobuf_queue {
133 struct mutex vb_lock;
134 struct mutex *ext_lock;
135 spinlock_t *irqlock;
136 struct device *dev;
137
138 wait_queue_head_t wait; /* wait if queue is empty */
139
140 enum v4l2_buf_type type;
141 unsigned int msize;
142 enum v4l2_field field;
143 enum v4l2_field last; /* for field=V4L2_FIELD_ALTERNATE */
144 struct videobuf_buffer *bufs[VIDEO_MAX_FRAME];
145 const struct videobuf_queue_ops *ops;
146 struct videobuf_qtype_ops *int_ops;
147
148 unsigned int streaming:1;
149 unsigned int reading:1;
150
151 /* capture via mmap() + ioctl(QBUF/DQBUF) */
152 struct list_head stream;
153
154 /* capture via read() */
155 unsigned int read_off;
156 struct videobuf_buffer *read_buf;
157
158 /* driver private data */
159 void *priv_data;
160 };
161
videobuf_queue_lock(struct videobuf_queue * q)162 static inline void videobuf_queue_lock(struct videobuf_queue *q)
163 {
164 if (!q->ext_lock)
165 mutex_lock(&q->vb_lock);
166 }
167
videobuf_queue_unlock(struct videobuf_queue * q)168 static inline void videobuf_queue_unlock(struct videobuf_queue *q)
169 {
170 if (!q->ext_lock)
171 mutex_unlock(&q->vb_lock);
172 }
173
174 int videobuf_waiton(struct videobuf_queue *q, struct videobuf_buffer *vb,
175 int non_blocking, int intr);
176 int videobuf_iolock(struct videobuf_queue *q, struct videobuf_buffer *vb,
177 struct v4l2_framebuffer *fbuf);
178
179 struct videobuf_buffer *videobuf_alloc_vb(struct videobuf_queue *q);
180
181 /* Used on videobuf-dvb */
182 void *videobuf_queue_to_vaddr(struct videobuf_queue *q,
183 struct videobuf_buffer *buf);
184
185 void videobuf_queue_core_init(struct videobuf_queue *q,
186 const struct videobuf_queue_ops *ops,
187 struct device *dev,
188 spinlock_t *irqlock,
189 enum v4l2_buf_type type,
190 enum v4l2_field field,
191 unsigned int msize,
192 void *priv,
193 struct videobuf_qtype_ops *int_ops,
194 struct mutex *ext_lock);
195 int videobuf_queue_is_busy(struct videobuf_queue *q);
196 void videobuf_queue_cancel(struct videobuf_queue *q);
197
198 enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
199 int videobuf_reqbufs(struct videobuf_queue *q,
200 struct v4l2_requestbuffers *req);
201 int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
202 int videobuf_qbuf(struct videobuf_queue *q,
203 struct v4l2_buffer *b);
204 int videobuf_dqbuf(struct videobuf_queue *q,
205 struct v4l2_buffer *b, int nonblocking);
206 int videobuf_streamon(struct videobuf_queue *q);
207 int videobuf_streamoff(struct videobuf_queue *q);
208
209 void videobuf_stop(struct videobuf_queue *q);
210
211 int videobuf_read_start(struct videobuf_queue *q);
212 void videobuf_read_stop(struct videobuf_queue *q);
213 ssize_t videobuf_read_stream(struct videobuf_queue *q,
214 char __user *data, size_t count, loff_t *ppos,
215 int vbihack, int nonblocking);
216 ssize_t videobuf_read_one(struct videobuf_queue *q,
217 char __user *data, size_t count, loff_t *ppos,
218 int nonblocking);
219 __poll_t videobuf_poll_stream(struct file *file,
220 struct videobuf_queue *q,
221 poll_table *wait);
222
223 int videobuf_mmap_setup(struct videobuf_queue *q,
224 unsigned int bcount, unsigned int bsize,
225 enum v4l2_memory memory);
226 int __videobuf_mmap_setup(struct videobuf_queue *q,
227 unsigned int bcount, unsigned int bsize,
228 enum v4l2_memory memory);
229 int videobuf_mmap_free(struct videobuf_queue *q);
230 int videobuf_mmap_mapper(struct videobuf_queue *q,
231 struct vm_area_struct *vma);
232
233 #endif
234