drivers/media/test-drivers/vidtv/vidtv_ts.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * The Virtual DVB test driver serves as a reference DVB driver and helps
   4  * validate the existing APIs in the media subsystem. It can also aid
   5  * developers working on userspace applications.
   6  *
   7  * Copyright (C) 2020 Daniel W. S. Almeida
   8  */
   9
  10 #ifndef VIDTV_TS_H
  11 #define VIDTV_TS_H
  12
  13 #include <linux/types.h>
  14
  15 #define TS_SYNC_BYTE 0x47
  16 #define TS_PACKET_LEN 188
  17 #define TS_PAYLOAD_LEN 184
  18 #define TS_NULL_PACKET_PID 0x1fff
  19 #define TS_CC_MAX_VAL 0x0f /* 4 bits */
  20 #define TS_LAST_VALID_PID 8191
  21 #define TS_FILL_BYTE 0xff /* the byte used in packet stuffing */
  22
  23 struct vidtv_mpeg_ts_adaption {
  24         u8 length;
  25         struct {
  26                 u8 extension:1;
  27                 u8 private_data:1;
  28                 u8 splicing_point:1;
  29                 u8 OPCR:1;
  30                 u8 PCR:1;
  31                 u8 priority:1;
  32                 u8 random_access:1;
  33                 u8 discontinued:1;
  34         } __packed;
  35         u8 data[];
  36 } __packed;
  37
  38 struct vidtv_mpeg_ts {
  39         u8 sync_byte;
  40         __be16 bitfield; /* tei: 1, payload_start:1 priority: 1, pid:13 */
  41         struct {
  42                 u8 continuity_counter:4;
  43                 u8 payload:1;
  44                 u8 adaptation_field:1;
  45                 u8 scrambling:2;
  46         } __packed;
  47         struct vidtv_mpeg_ts_adaption *adaption;
  48 } __packed;
  49
  50 /**
  51  * struct pcr_write_args - Arguments for the pcr_write_into function.
  52  * @dest_buf: The buffer to write into.
  53  * @dest_offset: The byte offset into the buffer.
  54  * @pid: The TS PID for the PCR packets.
  55  * @buf_sz: The size of the buffer in bytes.
  56  * @continuity_counter: The TS continuity_counter.
  57  * @pcr: A sample from the system clock.
  58  */
  59 struct pcr_write_args {
  60         void *dest_buf;
  61         u32 dest_offset;
  62         u16 pid;
  63         u32 buf_sz;
  64         u8 *continuity_counter;
  65         u64 pcr;
  66 };
  67
  68 /**
  69  * struct null_packet_write_args - Arguments for the null_write_into function
  70  * @dest_buf: The buffer to write into.
  71  * @dest_offset: The byte offset into the buffer.
  72  * @buf_sz: The size of the buffer in bytes.
  73  * @continuity_counter: The TS continuity_counter.
  74  */
  75 struct null_packet_write_args {
  76         void *dest_buf;
  77         u32 dest_offset;
  78         u32 buf_sz;
  79         u8 *continuity_counter;
  80 };
  81
  82 /* Increment the continuity counter */
  83 void vidtv_ts_inc_cc(u8 *continuity_counter);
  84
  85 /**
  86  * vidtv_ts_null_write_into - Write a TS null packet into a buffer.
  87  * @args: the arguments to use when writing.
  88  *
  89  * This function will write a null packet into a buffer. This is usually used to
  90  * pad TS streams.
  91  *
  92  * Return: The number of bytes written into the buffer.
  93  */
  94 u32 vidtv_ts_null_write_into(struct null_packet_write_args args);
  95
  96 /**
  97  * vidtv_ts_pcr_write_into - Write a PCR  packet into a buffer.
  98  * @args: the arguments to use when writing.
  99  *
 100  * This function will write a PCR packet into a buffer. This is used to
 101  * synchronize the clocks between encoders and decoders.
 102  *
 103  * Return: The number of bytes written into the buffer.
 104  */
 105 u32 vidtv_ts_pcr_write_into(struct pcr_write_args args);
 106
 107 #endif //VIDTV_TS_H