1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 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 16 static void wss_insert(u8 *wss, u32 val, unsigned size) 17 { 18 while (size--) 19 *wss++ = (val & (1 << size)) ? 0xc0 : 0x10; 20 } 21 22 static 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 48 static 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 69 static 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 83 static 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, 1 95 }; 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 } 108 109 void 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 else 129 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 } 139 140 static 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 }; 150 151 static 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 }; 165 166 static 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 } 175 176 static 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 else 202 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 } 209 210 static const u8 hamming[16] = { 211 0x15, 0x02, 0x49, 0x5e, 0x64, 0x73, 0x38, 0x2f, 212 0xd0, 0xc7, 0x8c, 0x9b, 0xa1, 0xb6, 0xfd, 0xea 213 }; 214 215 static 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 } 244 245 void 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