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1/* SPDX-License-Identifier: GPL-2.0 */2/*3 * Vidtv serves as a reference DVB driver and helps validate the existing APIs4 * in the media subsystem. It can also aid developers working on userspace5 * applications.6 *7 * This file contains the muxer logic for TS packets from different8 * elementary streams.9 *10 * Loosely based on libavcodec/mpegtsenc.c11 *12 * Copyright (C) 2020 Daniel W. S. Almeida13 */14 15#ifndef VIDTV_MUX_H16#define VIDTV_MUX_H17 18#include <linux/hashtable.h>19#include <linux/types.h>20#include <linux/workqueue.h>21 22#include <media/dvb_frontend.h>23 24#include "vidtv_psi.h"25 26/**27 * struct vidtv_mux_timing - Timing related information28 *29 * This is used to decide when PCR or PSI packets should be sent. This will also30 * provide storage for the clock, which is used to compute the value for the PCR.31 *32 * @start_jiffies: The value of 'jiffies' when we started the mux thread.33 * @current_jiffies: The value of 'jiffies' for the current iteration.34 * @past_jiffies: The value of 'jiffies' for the past iteration.35 * @clk: A 27Mhz clock from which we will drive the PCR. Updated proportionally36 * on every iteration.37 * @pcr_period_usecs: How often we should send PCR packets.38 * @si_period_usecs: How often we should send PSI packets.39 */40struct vidtv_mux_timing {41 u64 start_jiffies;42 u64 current_jiffies;43 u64 past_jiffies;44 45 u64 clk;46 47 u64 pcr_period_usecs;48 u64 si_period_usecs;49};50 51/**52 * struct vidtv_mux_si - Store the PSI context.53 *54 * This is used to store the PAT, PMT sections and SDT in use by the muxer.55 *56 * The muxer acquire these by looking into the hardcoded channels in57 * vidtv_channel and then periodically sends the TS packets for them>58 *59 * @pat: The PAT in use by the muxer.60 * @pmt_secs: The PMT sections in use by the muxer. One for each program in the PAT.61 * @sdt: The SDT in use by the muxer.62 * @nit: The NIT in use by the muxer.63 * @eit: the EIT in use by the muxer.64 */65struct vidtv_mux_si {66 /* the SI tables */67 struct vidtv_psi_table_pat *pat;68 struct vidtv_psi_table_pmt **pmt_secs; /* the PMT sections */69 struct vidtv_psi_table_sdt *sdt;70 struct vidtv_psi_table_nit *nit;71 struct vidtv_psi_table_eit *eit;72};73 74/**75 * struct vidtv_mux_pid_ctx - Store the context for a given TS PID.76 * @pid: The TS PID.77 * @cc: The continuity counter for this PID. It is incremented on every TS78 * pack and it will wrap around at 0xf0. If the decoder notices a sudden jump in79 * this counter this will trigger a discontinuity state.80 * @h: This is embedded in a hash table, mapping pid -> vidtv_mux_pid_ctx81 */82struct vidtv_mux_pid_ctx {83 u16 pid;84 u8 cc; /* continuity counter */85 struct hlist_node h;86};87 88/**89 * struct vidtv_mux - A muxer abstraction loosely based in libavcodec/mpegtsenc.c90 * @fe: The frontend structure allocated by the muxer.91 * @dev: pointer to struct device.92 * @timing: Keeps track of timing related information.93 * @mux_rate_kbytes_sec: The bit rate for the TS, in kbytes.94 * @pid_ctx: A hash table to keep track of per-PID metadata.95 * @on_new_packets_available_cb: A callback to inform of new TS packets ready.96 * @mux_buf: A pointer to a buffer for this muxer. TS packets are stored there97 * and then passed on to the bridge driver.98 * @mux_buf_sz: The size for 'mux_buf'.99 * @mux_buf_offset: The current offset into 'mux_buf'.100 * @channels: The channels associated with this muxer.101 * @si: Keeps track of the PSI context.102 * @num_streamed_pcr: Number of PCR packets streamed.103 * @num_streamed_si: The number of PSI packets streamed.104 * @mpeg_thread: Thread responsible for the muxer loop.105 * @streaming: whether 'mpeg_thread' is running.106 * @pcr_pid: The TS PID used for the PSI packets. All channels will share the107 * same PCR.108 * @transport_stream_id: The transport stream ID109 * @network_id: The network ID110 * @network_name: The network name111 * @priv: Private data.112 */113struct vidtv_mux {114 struct dvb_frontend *fe;115 struct device *dev;116 117 struct vidtv_mux_timing timing;118 119 u32 mux_rate_kbytes_sec;120 121 DECLARE_HASHTABLE(pid_ctx, 3);122 123 void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets);124 125 u8 *mux_buf;126 u32 mux_buf_sz;127 u32 mux_buf_offset;128 129 struct vidtv_channel *channels;130 131 struct vidtv_mux_si si;132 u64 num_streamed_pcr;133 u64 num_streamed_si;134 135 struct work_struct mpeg_thread;136 bool streaming;137 138 u16 pcr_pid;139 u16 transport_stream_id;140 u16 network_id;141 char *network_name;142 void *priv;143};144 145/**146 * struct vidtv_mux_init_args - Arguments used to inix the muxer.147 * @mux_rate_kbytes_sec: The bit rate for the TS, in kbytes.148 * @on_new_packets_available_cb: A callback to inform of new TS packets ready.149 * @mux_buf_sz: The size for 'mux_buf'.150 * @pcr_period_usecs: How often we should send PCR packets.151 * @si_period_usecs: How often we should send PSI packets.152 * @pcr_pid: The TS PID used for the PSI packets. All channels will share the153 * same PCR.154 * @transport_stream_id: The transport stream ID155 * @channels: an optional list of channels to use156 * @network_id: The network ID157 * @network_name: The network name158 * @priv: Private data.159 */160struct vidtv_mux_init_args {161 u32 mux_rate_kbytes_sec;162 void (*on_new_packets_available_cb)(void *priv, u8 *buf, u32 npackets);163 u32 mux_buf_sz;164 u64 pcr_period_usecs;165 u64 si_period_usecs;166 u16 pcr_pid;167 u16 transport_stream_id;168 struct vidtv_channel *channels;169 u16 network_id;170 char *network_name;171 void *priv;172};173 174struct vidtv_mux *vidtv_mux_init(struct dvb_frontend *fe,175 struct device *dev,176 struct vidtv_mux_init_args *args);177void vidtv_mux_destroy(struct vidtv_mux *m);178 179void vidtv_mux_start_thread(struct vidtv_mux *m);180void vidtv_mux_stop_thread(struct vidtv_mux *m);181 182#endif //VIDTV_MUX_H183