1 /*
2  * SPDX-License-Identifier: GPL-2.0
3  *
4  * dvb-vb2.h - DVB driver helper framework for streaming I/O
5  *
6  * Copyright (C) 2015 Samsung Electronics
7  *
8  * Author: jh1009.sung@samsung.com
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation.
13  */
14 
15 #ifndef _DVB_VB2_H
16 #define _DVB_VB2_H
17 
18 #include <linux/mutex.h>
19 #include <linux/poll.h>
20 #include <linux/dvb/dmx.h>
21 #include <media/videobuf2-core.h>
22 #include <media/videobuf2-dma-contig.h>
23 #include <media/videobuf2-vmalloc.h>
24 
25 /**
26  * enum dvb_buf_type - types of Digital TV memory-mapped buffers
27  *
28  * @DVB_BUF_TYPE_CAPTURE: buffer is filled by the Kernel,
29  *			  with a received Digital TV stream
30  */
31 enum dvb_buf_type {
32 	DVB_BUF_TYPE_CAPTURE        = 1,
33 };
34 
35 /**
36  * enum dvb_vb2_states - states to control VB2 state machine
37  * @DVB_VB2_STATE_NONE:
38  *	VB2 engine not initialized yet, init failed or VB2 was released.
39  * @DVB_VB2_STATE_INIT:
40  *	VB2 engine initialized.
41  * @DVB_VB2_STATE_REQBUFS:
42  *	Buffers were requested
43  * @DVB_VB2_STATE_STREAMON:
44  *	VB2 is streaming. Callers should not check it directly. Instead,
45  *	they should use dvb_vb2_is_streaming().
46  *
47  * Note:
48  *
49  * Callers should not touch at the state machine directly. This
50  * is handled inside dvb_vb2.c.
51  */
52 enum dvb_vb2_states {
53 	DVB_VB2_STATE_NONE	= 0x0,
54 	DVB_VB2_STATE_INIT	= 0x1,
55 	DVB_VB2_STATE_REQBUFS	= 0x2,
56 	DVB_VB2_STATE_STREAMON	= 0x4,
57 };
58 
59 #define DVB_VB2_NAME_MAX (20)
60 
61 /**
62  * struct dvb_buffer - video buffer information for v4l2.
63  *
64  * @vb:		embedded struct &vb2_buffer.
65  * @list:	list of &struct dvb_buffer.
66  */
67 struct dvb_buffer {
68 	struct vb2_buffer	vb;
69 	struct list_head	list;
70 };
71 
72 /**
73  * struct dvb_vb2_ctx - control struct for VB2 handler
74  * @vb_q:	pointer to &struct vb2_queue with videobuf2 queue.
75  * @mutex:	mutex to serialize vb2 operations. Used by
76  *		vb2 core %wait_prepare and %wait_finish operations.
77  * @slock:	spin lock used to protect buffer filling at dvb_vb2.c.
78  * @dvb_q:	List of buffers that are not filled yet.
79  * @buf:	Pointer to the buffer that are currently being filled.
80  * @offset:	index to the next position at the @buf to be filled.
81  * @remain:	How many bytes are left to be filled at @buf.
82  * @state:	bitmask of buffer states as defined by &enum dvb_vb2_states.
83  * @buf_siz:	size of each VB2 buffer.
84  * @buf_cnt:	number of VB2 buffers.
85  * @nonblocking:
86  *		If different than zero, device is operating on non-blocking
87  *		mode.
88  * @flags:	buffer flags as defined by &enum dmx_buffer_flags.
89  *		Filled only at &DMX_DQBUF. &DMX_QBUF should zero this field.
90  * @count:	monotonic counter for filled buffers. Helps to identify
91  *		data stream loses. Filled only at &DMX_DQBUF. &DMX_QBUF should
92  *		zero this field.
93  *
94  * @name:	name of the device type. Currently, it can either be
95  *		"dvr" or "demux_filter".
96  */
97 struct dvb_vb2_ctx {
98 	struct vb2_queue	vb_q;
99 	struct mutex		mutex;
100 	spinlock_t		slock;
101 	struct list_head	dvb_q;
102 	struct dvb_buffer	*buf;
103 	int	offset;
104 	int	remain;
105 	int	state;
106 	int	buf_siz;
107 	int	buf_cnt;
108 	int	nonblocking;
109 
110 	enum dmx_buffer_flags flags;
111 	u32	count;
112 
113 	char	name[DVB_VB2_NAME_MAX + 1];
114 };
115 
116 #ifndef CONFIG_DVB_MMAP
dvb_vb2_init(struct dvb_vb2_ctx * ctx,const char * name,int non_blocking)117 static inline int dvb_vb2_init(struct dvb_vb2_ctx *ctx,
118 			       const char *name, int non_blocking)
119 {
120 	return 0;
121 };
dvb_vb2_release(struct dvb_vb2_ctx * ctx)122 static inline int dvb_vb2_release(struct dvb_vb2_ctx *ctx)
123 {
124 	return 0;
125 };
126 #define dvb_vb2_is_streaming(ctx) (0)
127 #define dvb_vb2_fill_buffer(ctx, file, wait, flags) (0)
128 
dvb_vb2_poll(struct dvb_vb2_ctx * ctx,struct file * file,poll_table * wait)129 static inline __poll_t dvb_vb2_poll(struct dvb_vb2_ctx *ctx,
130 				    struct file *file,
131 				    poll_table *wait)
132 {
133 	return 0;
134 }
135 #else
136 /**
137  * dvb_vb2_init - initializes VB2 handler
138  *
139  * @ctx:	control struct for VB2 handler
140  * @name:	name for the VB2 handler
141  * @non_blocking:
142  *		if not zero, it means that the device is at non-blocking mode
143  */
144 int dvb_vb2_init(struct dvb_vb2_ctx *ctx, const char *name, int non_blocking);
145 
146 /**
147  * dvb_vb2_release - Releases the VB2 handler allocated resources and
148  *	put @ctx at DVB_VB2_STATE_NONE state.
149  * @ctx:	control struct for VB2 handler
150  */
151 int dvb_vb2_release(struct dvb_vb2_ctx *ctx);
152 
153 /**
154  * dvb_vb2_is_streaming - checks if the VB2 handler is streaming
155  * @ctx:	control struct for VB2 handler
156  *
157  * Return: 0 if not streaming, 1 otherwise.
158  */
159 int dvb_vb2_is_streaming(struct dvb_vb2_ctx *ctx);
160 
161 /**
162  * dvb_vb2_fill_buffer - fills a VB2 buffer
163  * @ctx:	control struct for VB2 handler
164  * @src:	place where the data is stored
165  * @len:	number of bytes to be copied from @src
166  * @buffer_flags:
167  *		pointer to buffer flags as defined by &enum dmx_buffer_flags.
168  *		can be NULL.
169  */
170 int dvb_vb2_fill_buffer(struct dvb_vb2_ctx *ctx,
171 			const unsigned char *src, int len,
172 			enum dmx_buffer_flags *buffer_flags);
173 
174 /**
175  * dvb_vb2_poll - Wrapper to vb2_core_streamon() for Digital TV
176  *      buffer handling.
177  *
178  * @ctx:	control struct for VB2 handler
179  * @file:	&struct file argument passed to the poll
180  *		file operation handler.
181  * @wait:	&poll_table wait argument passed to the poll
182  *		file operation handler.
183  *
184  * Implements poll syscall() logic.
185  */
186 __poll_t dvb_vb2_poll(struct dvb_vb2_ctx *ctx, struct file *file,
187 		      poll_table *wait);
188 #endif
189 
190 /**
191  * dvb_vb2_stream_on() - Wrapper to vb2_core_streamon() for Digital TV
192  *	buffer handling.
193  *
194  * @ctx:	control struct for VB2 handler
195  *
196  * Starts dvb streaming
197  */
198 int dvb_vb2_stream_on(struct dvb_vb2_ctx *ctx);
199 /**
200  * dvb_vb2_stream_off() - Wrapper to vb2_core_streamoff() for Digital TV
201  *	buffer handling.
202  *
203  * @ctx:	control struct for VB2 handler
204  *
205  * Stops dvb streaming
206  */
207 int dvb_vb2_stream_off(struct dvb_vb2_ctx *ctx);
208 
209 /**
210  * dvb_vb2_reqbufs() - Wrapper to vb2_core_reqbufs() for Digital TV
211  *	buffer handling.
212  *
213  * @ctx:	control struct for VB2 handler
214  * @req:	&struct dmx_requestbuffers passed from userspace in
215  *		order to handle &DMX_REQBUFS.
216  *
217  * Initiate streaming by requesting a number of buffers. Also used to
218  * free previously requested buffers, is ``req->count`` is zero.
219  */
220 int dvb_vb2_reqbufs(struct dvb_vb2_ctx *ctx, struct dmx_requestbuffers *req);
221 
222 /**
223  * dvb_vb2_querybuf() - Wrapper to vb2_core_querybuf() for Digital TV
224  *	buffer handling.
225  *
226  * @ctx:	control struct for VB2 handler
227  * @b:		&struct dmx_buffer passed from userspace in
228  *		order to handle &DMX_QUERYBUF.
229  *
230  *
231  */
232 int dvb_vb2_querybuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b);
233 
234 /**
235  * dvb_vb2_expbuf() - Wrapper to vb2_core_expbuf() for Digital TV
236  *	buffer handling.
237  *
238  * @ctx:	control struct for VB2 handler
239  * @exp:	&struct dmx_exportbuffer passed from userspace in
240  *		order to handle &DMX_EXPBUF.
241  *
242  * Export a buffer as a file descriptor.
243  */
244 int dvb_vb2_expbuf(struct dvb_vb2_ctx *ctx, struct dmx_exportbuffer *exp);
245 
246 /**
247  * dvb_vb2_qbuf() - Wrapper to vb2_core_qbuf() for Digital TV buffer handling.
248  *
249  * @ctx:	control struct for VB2 handler
250  * @b:		&struct dmx_buffer passed from userspace in
251  *		order to handle &DMX_QBUF.
252  *
253  * Queue a Digital TV buffer as requested by userspace
254  */
255 int dvb_vb2_qbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b);
256 
257 /**
258  * dvb_vb2_dqbuf() - Wrapper to vb2_core_dqbuf() for Digital TV
259  *	buffer handling.
260  *
261  * @ctx:	control struct for VB2 handler
262  * @b:		&struct dmx_buffer passed from userspace in
263  *		order to handle &DMX_DQBUF.
264  *
265  * Dequeue a Digital TV buffer to the userspace
266  */
267 int dvb_vb2_dqbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b);
268 
269 /**
270  * dvb_vb2_mmap() - Wrapper to vb2_mmap() for Digital TV buffer handling.
271  *
272  * @ctx:	control struct for VB2 handler
273  * @vma:        pointer to &struct vm_area_struct with the vma passed
274  *              to the mmap file operation handler in the driver.
275  *
276  * map Digital TV video buffers into application address space.
277  */
278 int dvb_vb2_mmap(struct dvb_vb2_ctx *ctx, struct vm_area_struct *vma);
279 
280 #endif /* _DVB_VB2_H */
281