// SPDX-License-Identifier: GPL-2.0
|
/*
|
* The Virtual DVB test driver 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.
|
*
|
* Copyright (C) 2020 Daniel W. S. Almeida
|
*/
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ":%s, %d: " fmt, __func__, __LINE__
|
|
#include <linux/math64.h>
|
#include <linux/printk.h>
|
#include <linux/ratelimit.h>
|
#include <linux/types.h>
|
|
#include "vidtv_common.h"
|
#include "vidtv_ts.h"
|
|
static u32 vidtv_ts_write_pcr_bits(u8 *to, u32 to_offset, u64 pcr)
|
{
|
/* Exact same from ffmpeg. PCR is a counter driven by a 27Mhz clock */
|
u64 div;
|
u64 rem;
|
u8 *buf = to + to_offset;
|
u64 pcr_low;
|
u64 pcr_high;
|
|
div = div64_u64_rem(pcr, 300, &rem);
|
|
pcr_low = rem; /* pcr_low = pcr % 300 */
|
pcr_high = div; /* pcr_high = pcr / 300 */
|
|
*buf++ = pcr_high >> 25;
|
*buf++ = pcr_high >> 17;
|
*buf++ = pcr_high >> 9;
|
*buf++ = pcr_high >> 1;
|
*buf++ = pcr_high << 7 | pcr_low >> 8 | 0x7e;
|
*buf++ = pcr_low;
|
|
return 6;
|
}
|
|
void vidtv_ts_inc_cc(u8 *continuity_counter)
|
{
|
++*continuity_counter;
|
if (*continuity_counter > TS_CC_MAX_VAL)
|
*continuity_counter = 0;
|
}
|
|
u32 vidtv_ts_null_write_into(struct null_packet_write_args args)
|
{
|
u32 nbytes = 0;
|
struct vidtv_mpeg_ts ts_header = {};
|
|
ts_header.sync_byte = TS_SYNC_BYTE;
|
ts_header.bitfield = cpu_to_be16(TS_NULL_PACKET_PID);
|
ts_header.payload = 1;
|
ts_header.continuity_counter = *args.continuity_counter;
|
|
/* copy TS header */
|
nbytes += vidtv_memcpy(args.dest_buf,
|
args.dest_offset + nbytes,
|
args.buf_sz,
|
&ts_header,
|
sizeof(ts_header));
|
|
vidtv_ts_inc_cc(args.continuity_counter);
|
|
/* fill the rest with empty data */
|
nbytes += vidtv_memset(args.dest_buf,
|
args.dest_offset + nbytes,
|
args.buf_sz,
|
TS_FILL_BYTE,
|
TS_PACKET_LEN - nbytes);
|
|
/* we should have written exactly _one_ 188byte packet */
|
if (nbytes != TS_PACKET_LEN)
|
pr_warn_ratelimited("Expected exactly %d bytes, got %d\n",
|
TS_PACKET_LEN,
|
nbytes);
|
|
return nbytes;
|
}
|
|
u32 vidtv_ts_pcr_write_into(struct pcr_write_args args)
|
{
|
u32 nbytes = 0;
|
struct vidtv_mpeg_ts ts_header = {};
|
struct vidtv_mpeg_ts_adaption ts_adap = {};
|
|
ts_header.sync_byte = TS_SYNC_BYTE;
|
ts_header.bitfield = cpu_to_be16(args.pid);
|
ts_header.scrambling = 0;
|
/* cc is not incremented, but it is needed. see 13818-1 clause 2.4.3.3 */
|
ts_header.continuity_counter = *args.continuity_counter;
|
ts_header.payload = 0;
|
ts_header.adaptation_field = 1;
|
|
/* 13818-1 clause 2.4.3.5 */
|
ts_adap.length = 183;
|
ts_adap.PCR = 1;
|
|
/* copy TS header */
|
nbytes += vidtv_memcpy(args.dest_buf,
|
args.dest_offset + nbytes,
|
args.buf_sz,
|
&ts_header,
|
sizeof(ts_header));
|
|
/* write the adap after the TS header */
|
nbytes += vidtv_memcpy(args.dest_buf,
|
args.dest_offset + nbytes,
|
args.buf_sz,
|
&ts_adap,
|
sizeof(ts_adap));
|
|
/* write the PCR optional */
|
nbytes += vidtv_ts_write_pcr_bits(args.dest_buf,
|
args.dest_offset + nbytes,
|
args.pcr);
|
|
nbytes += vidtv_memset(args.dest_buf,
|
args.dest_offset + nbytes,
|
args.buf_sz,
|
TS_FILL_BYTE,
|
TS_PACKET_LEN - nbytes);
|
|
/* we should have written exactly _one_ 188byte packet */
|
if (nbytes != TS_PACKET_LEN)
|
pr_warn_ratelimited("Expected exactly %d bytes, got %d\n",
|
TS_PACKET_LEN,
|
nbytes);
|
|
return nbytes;
|
}
|
