blob: 70a4024d461e3a263d8dcac39049d2c843d4cc81 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* vivid-vbi-gen.c - vbi generator support functions.
*
* Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/string.h>
#include <linux/videodev2.h>
#include "vivid-vbi-gen.h"
static void wss_insert(u8 *wss, u32 val, unsigned size)
{
while (size--)
*wss++ = (val & (1 << size)) ? 0xc0 : 0x10;
}
static void vivid_vbi_gen_wss_raw(const struct v4l2_sliced_vbi_data *data,
u8 *buf, unsigned sampling_rate)
{
const unsigned rate = 5000000; /* WSS has a 5 MHz transmission rate */
u8 wss[29 + 24 + 24 + 24 + 18 + 18] = { 0 };
const unsigned zero = 0x07;
const unsigned one = 0x38;
unsigned bit = 0;
u16 wss_data;
int i;
wss_insert(wss + bit, 0x1f1c71c7, 29); bit += 29;
wss_insert(wss + bit, 0x1e3c1f, 24); bit += 24;
wss_data = (data->data[1] << 8) | data->data[0];
for (i = 0; i <= 13; i++, bit += 6)
wss_insert(wss + bit, (wss_data & (1 << i)) ? one : zero, 6);
for (i = 0, bit = 0; bit < sizeof(wss); bit++) {
unsigned n = ((bit + 1) * sampling_rate) / rate;
while (i < n)
buf[i++] = wss[bit];
}
}
static void vivid_vbi_gen_teletext_raw(const struct v4l2_sliced_vbi_data *data,
u8 *buf, unsigned sampling_rate)
{
const unsigned rate = 6937500 / 10; /* Teletext has a 6.9375 MHz transmission rate */
u8 teletext[45] = { 0x55, 0x55, 0x27 };
unsigned bit = 0;
int i;
memcpy(teletext + 3, data->data, sizeof(teletext) - 3);
/* prevents 32 bit overflow */
sampling_rate /= 10;
for (i = 0, bit = 0; bit < sizeof(teletext) * 8; bit++) {
unsigned n = ((bit + 1) * sampling_rate) / rate;
u8 val = (teletext[bit / 8] & (1 << (bit & 7))) ? 0xc0 : 0x10;
while (i < n)
buf[i++] = val;
}
}
static void cc_insert(u8 *cc, u8 ch)
{
unsigned tot = 0;
unsigned i;
for (i = 0; i < 7; i++) {
cc[2 * i] = cc[2 * i + 1] = (ch & (1 << i)) ? 1 : 0;
tot += cc[2 * i];
}
cc[14] = cc[15] = !(tot & 1);
}
#define CC_PREAMBLE_BITS (14 + 4 + 2)
static void vivid_vbi_gen_cc_raw(const struct v4l2_sliced_vbi_data *data,
u8 *buf, unsigned sampling_rate)
{
const unsigned rate = 1000000; /* CC has a 1 MHz transmission rate */
u8 cc[CC_PREAMBLE_BITS + 2 * 16] = {
/* Clock run-in: 7 cycles */
0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
/* 2 cycles of 0 */
0, 0, 0, 0,
/* Start bit of 1 (each bit is two cycles) */
1, 1
};
unsigned bit, i;
cc_insert(cc + CC_PREAMBLE_BITS, data->data[0]);
cc_insert(cc + CC_PREAMBLE_BITS + 16, data->data[1]);
for (i = 0, bit = 0; bit < sizeof(cc); bit++) {
unsigned n = ((bit + 1) * sampling_rate) / rate;
while (i < n)
buf[i++] = cc[bit] ? 0xc0 : 0x10;
}
}
void vivid_vbi_gen_raw(const struct vivid_vbi_gen_data *vbi,
const struct v4l2_vbi_format *vbi_fmt, u8 *buf)
{
unsigned idx;
for (idx = 0; idx < 25; idx++) {
const struct v4l2_sliced_vbi_data *data = vbi->data + idx;
unsigned start_2nd_field;
unsigned line = data->line;
u8 *linebuf = buf;
start_2nd_field = (data->id & V4L2_SLICED_VBI_525) ? 263 : 313;
if (data->field)
line += start_2nd_field;
line -= vbi_fmt->start[data->field];
if (vbi_fmt->flags & V4L2_VBI_INTERLACED)
linebuf += (line * 2 + data->field) *
vbi_fmt->samples_per_line;
else
linebuf += (line + data->field * vbi_fmt->count[0]) *
vbi_fmt->samples_per_line;
if (data->id == V4L2_SLICED_CAPTION_525)
vivid_vbi_gen_cc_raw(data, linebuf, vbi_fmt->sampling_rate);
else if (data->id == V4L2_SLICED_WSS_625)
vivid_vbi_gen_wss_raw(data, linebuf, vbi_fmt->sampling_rate);
else if (data->id == V4L2_SLICED_TELETEXT_B)
vivid_vbi_gen_teletext_raw(data, linebuf, vbi_fmt->sampling_rate);
}
}
static const u8 vivid_cc_sequence1[30] = {
0x14, 0x20, /* Resume Caption Loading */
'H', 'e',
'l', 'l',
'o', ' ',
'w', 'o',
'r', 'l',
'd', '!',
0x14, 0x2f, /* End of Caption */
};
static const u8 vivid_cc_sequence2[30] = {
0x14, 0x20, /* Resume Caption Loading */
'C', 'l',
'o', 's',
'e', 'd',
' ', 'c',
'a', 'p',
't', 'i',
'o', 'n',
's', ' ',
't', 'e',
's', 't',
0x14, 0x2f, /* End of Caption */
};
static u8 calc_parity(u8 val)
{
unsigned i;
unsigned tot = 0;
for (i = 0; i < 7; i++)
tot += (val & (1 << i)) ? 1 : 0;
return val | ((tot & 1) ? 0 : 0x80);
}
static void vivid_vbi_gen_set_time_of_day(u8 *packet)
{
struct tm tm;
u8 checksum, i;
time64_to_tm(ktime_get_real_seconds(), 0, &tm);
packet[0] = calc_parity(0x07);
packet[1] = calc_parity(0x01);
packet[2] = calc_parity(0x40 | tm.tm_min);
packet[3] = calc_parity(0x40 | tm.tm_hour);
packet[4] = calc_parity(0x40 | tm.tm_mday);
if (tm.tm_mday == 1 && tm.tm_mon == 2 &&
sys_tz.tz_minuteswest > tm.tm_min + tm.tm_hour * 60)
packet[4] = calc_parity(0x60 | tm.tm_mday);
packet[5] = calc_parity(0x40 | (1 + tm.tm_mon));
packet[6] = calc_parity(0x40 | (1 + tm.tm_wday));
packet[7] = calc_parity(0x40 | ((tm.tm_year - 90) & 0x3f));
packet[8] = calc_parity(0x0f);
for (checksum = i = 0; i <= 8; i++)
checksum += packet[i] & 0x7f;
packet[9] = calc_parity(0x100 - checksum);
packet[10] = calc_parity(0x07);
packet[11] = calc_parity(0x04);
if (sys_tz.tz_minuteswest >= 0)
packet[12] = calc_parity(0x40 | ((sys_tz.tz_minuteswest / 60) & 0x1f));
else
packet[12] = calc_parity(0x40 | ((24 + sys_tz.tz_minuteswest / 60) & 0x1f));
packet[13] = calc_parity(0);
packet[14] = calc_parity(0x0f);
for (checksum = 0, i = 10; i <= 14; i++)
checksum += packet[i] & 0x7f;
packet[15] = calc_parity(0x100 - checksum);
}
static const u8 hamming[16] = {
0x15, 0x02, 0x49, 0x5e, 0x64, 0x73, 0x38, 0x2f,
0xd0, 0xc7, 0x8c, 0x9b, 0xa1, 0xb6, 0xfd, 0xea
};
static void vivid_vbi_gen_teletext(u8 *packet, unsigned line, unsigned frame)
{
unsigned offset = 2;
unsigned i;
packet[0] = hamming[1 + ((line & 1) << 3)];
packet[1] = hamming[line >> 1];
memset(packet + 2, 0x20, 40);
if (line == 0) {
/* subcode */
packet[2] = hamming[frame % 10];
packet[3] = hamming[frame / 10];
packet[4] = hamming[0];
packet[5] = hamming[0];
packet[6] = hamming[0];
packet[7] = hamming[0];
packet[8] = hamming[0];
packet[9] = hamming[1];
offset = 10;
}
packet += offset;
memcpy(packet, "Page: 100 Row: 10", 17);
packet[7] = '0' + frame / 10;
packet[8] = '0' + frame % 10;
packet[15] = '0' + line / 10;
packet[16] = '0' + line % 10;
for (i = 0; i < 42 - offset; i++)
packet[i] = calc_parity(packet[i]);
}
void vivid_vbi_gen_sliced(struct vivid_vbi_gen_data *vbi,
bool is_60hz, unsigned seqnr)
{
struct v4l2_sliced_vbi_data *data0 = vbi->data;
struct v4l2_sliced_vbi_data *data1 = vbi->data + 1;
unsigned frame = seqnr % 60;
memset(vbi->data, 0, sizeof(vbi->data));
if (!is_60hz) {
unsigned i;
for (i = 0; i <= 11; i++) {
data0->id = V4L2_SLICED_TELETEXT_B;
data0->line = 7 + i;
vivid_vbi_gen_teletext(data0->data, i, frame);
data0++;
}
data0->id = V4L2_SLICED_WSS_625;
data0->line = 23;
/* 4x3 video aspect ratio */
data0->data[0] = 0x08;
data0++;
for (i = 0; i <= 11; i++) {
data0->id = V4L2_SLICED_TELETEXT_B;
data0->field = 1;
data0->line = 7 + i;
vivid_vbi_gen_teletext(data0->data, 12 + i, frame);
data0++;
}
return;
}
data0->id = V4L2_SLICED_CAPTION_525;
data0->line = 21;
data1->id = V4L2_SLICED_CAPTION_525;
data1->field = 1;
data1->line = 21;
if (frame < 15) {
data0->data[0] = calc_parity(vivid_cc_sequence1[2 * frame]);
data0->data[1] = calc_parity(vivid_cc_sequence1[2 * frame + 1]);
} else if (frame >= 30 && frame < 45) {
frame -= 30;
data0->data[0] = calc_parity(vivid_cc_sequence2[2 * frame]);
data0->data[1] = calc_parity(vivid_cc_sequence2[2 * frame + 1]);
} else {
data0->data[0] = calc_parity(0);
data0->data[1] = calc_parity(0);
}
frame = seqnr % (30 * 60);
switch (frame) {
case 0:
vivid_vbi_gen_set_time_of_day(vbi->time_of_day_packet);
fallthrough;
case 1 ... 7:
data1->data[0] = vbi->time_of_day_packet[frame * 2];
data1->data[1] = vbi->time_of_day_packet[frame * 2 + 1];
break;
default:
data1->data[0] = calc_parity(0);
data1->data[1] = calc_parity(0);
break;
}
}