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