diff options
Diffstat (limited to 'drivers/media/test-drivers/vidtv/vidtv_mux.h')
| -rw-r--r-- | drivers/media/test-drivers/vidtv/vidtv_mux.h | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/drivers/media/test-drivers/vidtv/vidtv_mux.h b/drivers/media/test-drivers/vidtv/vidtv_mux.h new file mode 100644 index 000000000000..2caa60623e97 --- /dev/null +++ b/drivers/media/test-drivers/vidtv/vidtv_mux.h @@ -0,0 +1,167 @@ +/* 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 |