summaryrefslogtreecommitdiff
path: root/drivers/media/test-drivers/vidtv/vidtv_mux.h
blob: 2caa60623e971edb8591596daa2d88fa42d9f829 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Vidtv serves as a reference DVB driver and helps validate the existing APIs
 * in the media subsystem. It can also aid developers working on userspace
 * applications.
 *
 * This file contains the muxer logic for TS packets from different
 * elementary streams.
 *
 * Loosely based on libavcodec/mpegtsenc.c
 *
 * Copyright (C) 2020 Daniel W. S. Almeida
 */

#ifndef VIDTV_MUX_H
#define VIDTV_MUX_H

#include <linux/types.h>
#include <linux/hashtable.h>
#include <linux/workqueue.h>
#include <media/dvb_frontend.h>

#include "vidtv_psi.h"

/**
 * struct vidtv_mux_timing - Timing related information
 *
 * This is used to decide when PCR or PSI packets should be sent. This will also
 * provide storage for the clock, which is used to compute the value for the PCR.
 *
 * @start_jiffies: The value of 'jiffies' when we started the mux thread.
 * @current_jiffies: The value of 'jiffies' for the current iteration.
 * @past_jiffies: The value of 'jiffies' for the past iteration.
 * @clk: A 27Mhz clock from which we will drive the PCR. Updated proportionally
 * on every iteration.
 * @pcr_period_usecs: How often we should send PCR packets.
 * @si_period_usecs: How often we should send PSI packets.
 */
struct vidtv_mux_timing {
	u64 start_jiffies;
	u64 current_jiffies;
	u64 past_jiffies;

	u64 clk;

	u64 pcr_period_usecs;
	u64 si_period_usecs;
};

/**
 * struct vidtv_mux_si - Store the PSI context.
 *
 * This is used to store the PAT, PMT sections and SDT in use by the muxer.
 *
 * The muxer acquire these by looking into the hardcoded channels in
 * vidtv_channel and then periodically sends the TS packets for them>
 *
 * @pat: The PAT in use by the muxer.
 * @pmt_secs: The PMT sections in use by the muxer. One for each program in the PAT.
 * @sdt: The SDT in use by the muxer.
 */
struct vidtv_mux_si {
	/* the SI tables */
	struct vidtv_psi_table_pat *pat;
	struct vidtv_psi_table_pmt **pmt_secs; /* the PMT sections */
	struct vidtv_psi_table_sdt *sdt;
};

/**
 * struct vidtv_mux_pid_ctx - Store the context for a given TS PID.
 * @pid: The TS PID.
 * @cc: The continuity counter for this PID. It is incremented on every TS
 * pack and it will wrap around at 0xf0. If the decoder notices a sudden jump in
 * this counter this will trigger a discontinuity state.
 * @h: This is embedded in a hash table, mapping pid -> vidtv_mux_pid_ctx
 */
struct vidtv_mux_pid_ctx {
	u16 pid;
	u8 cc; /* continuity counter */
	struct hlist_node h;
};

/**
 * struct vidtv_mux - A muxer abstraction loosely based in libavcodec/mpegtsenc.c
 * @mux_rate_kbytes_sec: The bit rate for the TS, in kbytes.
 * @timing: Keeps track of timing related information.
 * @pid_ctx: A hash table to keep track of per-PID metadata.
 * @on_new_packets_available_cb: A callback to inform of new TS packets ready.
 * @mux_buf: A pointer to a buffer for this muxer. TS packets are stored there
 * and then passed on to the bridge driver.
 * @mux_buf_sz: The size for 'mux_buf'.
 * @mux_buf_offset: The current offset into 'mux_buf'.
 * @channels: The channels associated with this muxer.
 * @si: Keeps track of the PSI context.
 * @num_streamed_pcr: Number of PCR packets streamed.
 * @num_streamed_si: The number of PSI packets streamed.
 * @mpeg_thread: Thread responsible for the muxer loop.
 * @streaming: whether 'mpeg_thread' is running.
 * @pcr_pid: The TS PID used for the PSI packets. All channels will share the
 * same PCR.
 * @transport_stream_id: The transport stream ID
 * @priv: Private data.
 */
struct vidtv_mux {
	struct dvb_frontend *fe;
	struct device *dev;

	struct vidtv_mux_timing timing;

	u32 mux_rate_kbytes_sec;

	DECLARE_HASHTABLE(pid_ctx, 3);

	void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets);

	u8 *mux_buf;
	u32 mux_buf_sz;
	u32 mux_buf_offset;

	struct vidtv_channel  *channels;

	struct vidtv_mux_si si;
	u64 num_streamed_pcr;
	u64 num_streamed_si;

	struct work_struct mpeg_thread;
	bool streaming;

	u16 pcr_pid;
	u16 transport_stream_id;
	void *priv;
};

/**
 * struct vidtv_mux_init_args - Arguments used to inix the muxer.
 * @mux_rate_kbytes_sec: The bit rate for the TS, in kbytes.
 * @on_new_packets_available_cb: A callback to inform of new TS packets ready.
 * @mux_buf_sz: The size for 'mux_buf'.
 * @pcr_period_usecs: How often we should send PCR packets.
 * @si_period_usecs: How often we should send PSI packets.
 * @pcr_pid: The TS PID used for the PSI packets. All channels will share the
 * same PCR.
 * @transport_stream_id: The transport stream ID
 * @channels: an optional list of channels to use
 * @priv: Private data.
 */
struct vidtv_mux_init_args {
	u32 mux_rate_kbytes_sec;
	void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets);
	u32 mux_buf_sz;
	u64 pcr_period_usecs;
	u64 si_period_usecs;
	u16 pcr_pid;
	u16 transport_stream_id;
	struct vidtv_channel *channels;
	void *priv;
};

struct vidtv_mux *vidtv_mux_init(struct dvb_frontend *fe,
				 struct device *dev,
				 struct vidtv_mux_init_args args);
void vidtv_mux_destroy(struct vidtv_mux *m);

void vidtv_mux_start_thread(struct vidtv_mux *m);
void vidtv_mux_stop_thread(struct vidtv_mux *m);

#endif //VIDTV_MUX_H