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