311 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * vivid-vbi-gen.c - vbi generator support functions.4 *5 * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.6 */7 8#include <linux/errno.h>9#include <linux/kernel.h>10#include <linux/ktime.h>11#include <linux/string.h>12#include <linux/videodev2.h>13 14#include "vivid-vbi-gen.h"15 16static void wss_insert(u8 *wss, u32 val, unsigned size)17{18 while (size--)19 *wss++ = (val & (1 << size)) ? 0xc0 : 0x10;20}21 22static void vivid_vbi_gen_wss_raw(const struct v4l2_sliced_vbi_data *data,23 u8 *buf, unsigned sampling_rate)24{25 const unsigned rate = 5000000; /* WSS has a 5 MHz transmission rate */26 u8 wss[29 + 24 + 24 + 24 + 18 + 18] = { 0 };27 const unsigned zero = 0x07;28 const unsigned one = 0x38;29 unsigned bit = 0;30 u16 wss_data;31 int i;32 33 wss_insert(wss + bit, 0x1f1c71c7, 29); bit += 29;34 wss_insert(wss + bit, 0x1e3c1f, 24); bit += 24;35 36 wss_data = (data->data[1] << 8) | data->data[0];37 for (i = 0; i <= 13; i++, bit += 6)38 wss_insert(wss + bit, (wss_data & (1 << i)) ? one : zero, 6);39 40 for (i = 0, bit = 0; bit < sizeof(wss); bit++) {41 unsigned n = ((bit + 1) * sampling_rate) / rate;42 43 while (i < n)44 buf[i++] = wss[bit];45 }46}47 48static void vivid_vbi_gen_teletext_raw(const struct v4l2_sliced_vbi_data *data,49 u8 *buf, unsigned sampling_rate)50{51 const unsigned rate = 6937500 / 10; /* Teletext has a 6.9375 MHz transmission rate */52 u8 teletext[45] = { 0x55, 0x55, 0x27 };53 unsigned bit = 0;54 int i;55 56 memcpy(teletext + 3, data->data, sizeof(teletext) - 3);57 /* prevents 32 bit overflow */58 sampling_rate /= 10;59 60 for (i = 0, bit = 0; bit < sizeof(teletext) * 8; bit++) {61 unsigned n = ((bit + 1) * sampling_rate) / rate;62 u8 val = (teletext[bit / 8] & (1 << (bit & 7))) ? 0xc0 : 0x10;63 64 while (i < n)65 buf[i++] = val;66 }67}68 69static void cc_insert(u8 *cc, u8 ch)70{71 unsigned tot = 0;72 unsigned i;73 74 for (i = 0; i < 7; i++) {75 cc[2 * i] = cc[2 * i + 1] = (ch & (1 << i)) ? 1 : 0;76 tot += cc[2 * i];77 }78 cc[14] = cc[15] = !(tot & 1);79}80 81#define CC_PREAMBLE_BITS (14 + 4 + 2)82 83static void vivid_vbi_gen_cc_raw(const struct v4l2_sliced_vbi_data *data,84 u8 *buf, unsigned sampling_rate)85{86 const unsigned rate = 1000000; /* CC has a 1 MHz transmission rate */87 88 u8 cc[CC_PREAMBLE_BITS + 2 * 16] = {89 /* Clock run-in: 7 cycles */90 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,91 /* 2 cycles of 0 */92 0, 0, 0, 0,93 /* Start bit of 1 (each bit is two cycles) */94 1, 195 };96 unsigned bit, i;97 98 cc_insert(cc + CC_PREAMBLE_BITS, data->data[0]);99 cc_insert(cc + CC_PREAMBLE_BITS + 16, data->data[1]);100 101 for (i = 0, bit = 0; bit < sizeof(cc); bit++) {102 unsigned n = ((bit + 1) * sampling_rate) / rate;103 104 while (i < n)105 buf[i++] = cc[bit] ? 0xc0 : 0x10;106 }107}108 109void vivid_vbi_gen_raw(const struct vivid_vbi_gen_data *vbi,110 const struct v4l2_vbi_format *vbi_fmt, u8 *buf)111{112 unsigned idx;113 114 for (idx = 0; idx < 25; idx++) {115 const struct v4l2_sliced_vbi_data *data = vbi->data + idx;116 unsigned start_2nd_field;117 unsigned line = data->line;118 u8 *linebuf = buf;119 120 start_2nd_field = (data->id & V4L2_SLICED_VBI_525) ? 263 : 313;121 if (data->field)122 line += start_2nd_field;123 line -= vbi_fmt->start[data->field];124 125 if (vbi_fmt->flags & V4L2_VBI_INTERLACED)126 linebuf += (line * 2 + data->field) *127 vbi_fmt->samples_per_line;128 else129 linebuf += (line + data->field * vbi_fmt->count[0]) *130 vbi_fmt->samples_per_line;131 if (data->id == V4L2_SLICED_CAPTION_525)132 vivid_vbi_gen_cc_raw(data, linebuf, vbi_fmt->sampling_rate);133 else if (data->id == V4L2_SLICED_WSS_625)134 vivid_vbi_gen_wss_raw(data, linebuf, vbi_fmt->sampling_rate);135 else if (data->id == V4L2_SLICED_TELETEXT_B)136 vivid_vbi_gen_teletext_raw(data, linebuf, vbi_fmt->sampling_rate);137 }138}139 140static const u8 vivid_cc_sequence1[30] = {141 0x14, 0x20, /* Resume Caption Loading */142 'H', 'e',143 'l', 'l',144 'o', ' ',145 'w', 'o',146 'r', 'l',147 'd', '!',148 0x14, 0x2f, /* End of Caption */149};150 151static const u8 vivid_cc_sequence2[30] = {152 0x14, 0x20, /* Resume Caption Loading */153 'C', 'l',154 'o', 's',155 'e', 'd',156 ' ', 'c',157 'a', 'p',158 't', 'i',159 'o', 'n',160 's', ' ',161 't', 'e',162 's', 't',163 0x14, 0x2f, /* End of Caption */164};165 166static u8 calc_parity(u8 val)167{168 unsigned i;169 unsigned tot = 0;170 171 for (i = 0; i < 7; i++)172 tot += (val & (1 << i)) ? 1 : 0;173 return val | ((tot & 1) ? 0 : 0x80);174}175 176static void vivid_vbi_gen_set_time_of_day(u8 *packet)177{178 struct tm tm;179 u8 checksum, i;180 181 time64_to_tm(ktime_get_real_seconds(), 0, &tm);182 packet[0] = calc_parity(0x07);183 packet[1] = calc_parity(0x01);184 packet[2] = calc_parity(0x40 | tm.tm_min);185 packet[3] = calc_parity(0x40 | tm.tm_hour);186 packet[4] = calc_parity(0x40 | tm.tm_mday);187 if (tm.tm_mday == 1 && tm.tm_mon == 2 &&188 sys_tz.tz_minuteswest > tm.tm_min + tm.tm_hour * 60)189 packet[4] = calc_parity(0x60 | tm.tm_mday);190 packet[5] = calc_parity(0x40 | (1 + tm.tm_mon));191 packet[6] = calc_parity(0x40 | (1 + tm.tm_wday));192 packet[7] = calc_parity(0x40 | ((tm.tm_year - 90) & 0x3f));193 packet[8] = calc_parity(0x0f);194 for (checksum = i = 0; i <= 8; i++)195 checksum += packet[i] & 0x7f;196 packet[9] = calc_parity(0x100 - checksum);197 packet[10] = calc_parity(0x07);198 packet[11] = calc_parity(0x04);199 if (sys_tz.tz_minuteswest >= 0)200 packet[12] = calc_parity(0x40 | ((sys_tz.tz_minuteswest / 60) & 0x1f));201 else202 packet[12] = calc_parity(0x40 | ((24 + sys_tz.tz_minuteswest / 60) & 0x1f));203 packet[13] = calc_parity(0);204 packet[14] = calc_parity(0x0f);205 for (checksum = 0, i = 10; i <= 14; i++)206 checksum += packet[i] & 0x7f;207 packet[15] = calc_parity(0x100 - checksum);208}209 210static const u8 hamming[16] = {211 0x15, 0x02, 0x49, 0x5e, 0x64, 0x73, 0x38, 0x2f,212 0xd0, 0xc7, 0x8c, 0x9b, 0xa1, 0xb6, 0xfd, 0xea213};214 215static void vivid_vbi_gen_teletext(u8 *packet, unsigned line, unsigned frame)216{217 unsigned offset = 2;218 unsigned i;219 220 packet[0] = hamming[1 + ((line & 1) << 3)];221 packet[1] = hamming[line >> 1];222 memset(packet + 2, 0x20, 40);223 if (line == 0) {224 /* subcode */225 packet[2] = hamming[frame % 10];226 packet[3] = hamming[frame / 10];227 packet[4] = hamming[0];228 packet[5] = hamming[0];229 packet[6] = hamming[0];230 packet[7] = hamming[0];231 packet[8] = hamming[0];232 packet[9] = hamming[1];233 offset = 10;234 }235 packet += offset;236 memcpy(packet, "Page: 100 Row: 10", 17);237 packet[7] = '0' + frame / 10;238 packet[8] = '0' + frame % 10;239 packet[15] = '0' + line / 10;240 packet[16] = '0' + line % 10;241 for (i = 0; i < 42 - offset; i++)242 packet[i] = calc_parity(packet[i]);243}244 245void vivid_vbi_gen_sliced(struct vivid_vbi_gen_data *vbi,246 bool is_60hz, unsigned seqnr)247{248 struct v4l2_sliced_vbi_data *data0 = vbi->data;249 struct v4l2_sliced_vbi_data *data1 = vbi->data + 1;250 unsigned frame = seqnr % 60;251 252 memset(vbi->data, 0, sizeof(vbi->data));253 254 if (!is_60hz) {255 unsigned i;256 257 for (i = 0; i <= 11; i++) {258 data0->id = V4L2_SLICED_TELETEXT_B;259 data0->line = 7 + i;260 vivid_vbi_gen_teletext(data0->data, i, frame);261 data0++;262 }263 data0->id = V4L2_SLICED_WSS_625;264 data0->line = 23;265 /* 4x3 video aspect ratio */266 data0->data[0] = 0x08;267 data0++;268 for (i = 0; i <= 11; i++) {269 data0->id = V4L2_SLICED_TELETEXT_B;270 data0->field = 1;271 data0->line = 7 + i;272 vivid_vbi_gen_teletext(data0->data, 12 + i, frame);273 data0++;274 }275 return;276 }277 278 data0->id = V4L2_SLICED_CAPTION_525;279 data0->line = 21;280 data1->id = V4L2_SLICED_CAPTION_525;281 data1->field = 1;282 data1->line = 21;283 284 if (frame < 15) {285 data0->data[0] = calc_parity(vivid_cc_sequence1[2 * frame]);286 data0->data[1] = calc_parity(vivid_cc_sequence1[2 * frame + 1]);287 } else if (frame >= 30 && frame < 45) {288 frame -= 30;289 data0->data[0] = calc_parity(vivid_cc_sequence2[2 * frame]);290 data0->data[1] = calc_parity(vivid_cc_sequence2[2 * frame + 1]);291 } else {292 data0->data[0] = calc_parity(0);293 data0->data[1] = calc_parity(0);294 }295 296 frame = seqnr % (30 * 60);297 switch (frame) {298 case 0:299 vivid_vbi_gen_set_time_of_day(vbi->time_of_day_packet);300 fallthrough;301 case 1 ... 7:302 data1->data[0] = vbi->time_of_day_packet[frame * 2];303 data1->data[1] = vbi->time_of_day_packet[frame * 2 + 1];304 break;305 default:306 data1->data[0] = calc_parity(0);307 data1->data[1] = calc_parity(0);308 break;309 }310}311