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/bitops.h> 9 #include <linux/errno.h> 10 #include <linux/kernel.h> 11 #include <linux/ktime.h> 12 #include <linux/string.h> 13 #include <linux/videodev2.h> 14 15 #include "vivid-vbi-gen.h" 16 17 static void wss_insert(u8 *wss, u32 val, unsigned size) 18 { 19 while (size--) 20 *wss++ = (val & (1 << size)) ? 0xc0 : 0x10; 21 } 22 23 static void vivid_vbi_gen_wss_raw(const struct v4l2_sliced_vbi_data *data, 24 u8 *buf, unsigned sampling_rate) 25 { 26 const unsigned rate = 5000000; /* WSS has a 5 MHz transmission rate */ 27 u8 wss[29 + 24 + 24 + 24 + 18 + 18] = { 0 }; 28 const unsigned zero = 0x07; 29 const unsigned one = 0x38; 30 unsigned bit = 0; 31 u16 wss_data; 32 int i; 33 34 wss_insert(wss + bit, 0x1f1c71c7, 29); bit += 29; 35 wss_insert(wss + bit, 0x1e3c1f, 24); bit += 24; 36 37 wss_data = (data->data[1] << 8) | data->data[0]; 38 for (i = 0; i <= 13; i++, bit += 6) 39 wss_insert(wss + bit, (wss_data & (1 << i)) ? one : zero, 6); 40 41 for (i = 0, bit = 0; bit < sizeof(wss); bit++) { 42 unsigned n = ((bit + 1) * sampling_rate) / rate; 43 44 while (i < n) 45 buf[i++] = wss[bit]; 46 } 47 } 48 49 static void vivid_vbi_gen_teletext_raw(const struct v4l2_sliced_vbi_data *data, 50 u8 *buf, unsigned sampling_rate) 51 { 52 const unsigned rate = 6937500 / 10; /* Teletext has a 6.9375 MHz transmission rate */ 53 u8 teletext[45] = { 0x55, 0x55, 0x27 }; 54 unsigned bit = 0; 55 int i; 56 57 memcpy(teletext + 3, data->data, sizeof(teletext) - 3); 58 /* prevents 32 bit overflow */ 59 sampling_rate /= 10; 60 61 for (i = 0, bit = 0; bit < sizeof(teletext) * 8; bit++) { 62 unsigned n = ((bit + 1) * sampling_rate) / rate; 63 u8 val = (teletext[bit / 8] & (1 << (bit & 7))) ? 0xc0 : 0x10; 64 65 while (i < n) 66 buf[i++] = val; 67 } 68 } 69 70 static void cc_insert(u8 *cc, u8 ch) 71 { 72 unsigned tot = 0; 73 unsigned i; 74 75 for (i = 0; i < 7; i++) { 76 cc[2 * i] = cc[2 * i + 1] = (ch & (1 << i)) ? 1 : 0; 77 tot += cc[2 * i]; 78 } 79 cc[14] = cc[15] = !(tot & 1); 80 } 81 82 #define CC_PREAMBLE_BITS (14 + 4 + 2) 83 84 static void vivid_vbi_gen_cc_raw(const struct v4l2_sliced_vbi_data *data, 85 u8 *buf, unsigned sampling_rate) 86 { 87 const unsigned rate = 1000000; /* CC has a 1 MHz transmission rate */ 88 89 u8 cc[CC_PREAMBLE_BITS + 2 * 16] = { 90 /* Clock run-in: 7 cycles */ 91 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 92 /* 2 cycles of 0 */ 93 0, 0, 0, 0, 94 /* Start bit of 1 (each bit is two cycles) */ 95 1, 1 96 }; 97 unsigned bit, i; 98 99 cc_insert(cc + CC_PREAMBLE_BITS, data->data[0]); 100 cc_insert(cc + CC_PREAMBLE_BITS + 16, data->data[1]); 101 102 for (i = 0, bit = 0; bit < sizeof(cc); bit++) { 103 unsigned n = ((bit + 1) * sampling_rate) / rate; 104 105 while (i < n) 106 buf[i++] = cc[bit] ? 0xc0 : 0x10; 107 } 108 } 109 110 void vivid_vbi_gen_raw(const struct vivid_vbi_gen_data *vbi, 111 const struct v4l2_vbi_format *vbi_fmt, u8 *buf) 112 { 113 unsigned idx; 114 115 for (idx = 0; idx < 25; idx++) { 116 const struct v4l2_sliced_vbi_data *data = vbi->data + idx; 117 unsigned start_2nd_field; 118 unsigned line = data->line; 119 u8 *linebuf = buf; 120 121 start_2nd_field = (data->id & V4L2_SLICED_VBI_525) ? 263 : 313; 122 if (data->field) 123 line += start_2nd_field; 124 line -= vbi_fmt->start[data->field]; 125 126 if (vbi_fmt->flags & V4L2_VBI_INTERLACED) 127 linebuf += (line * 2 + data->field) * 128 vbi_fmt->samples_per_line; 129 else 130 linebuf += (line + data->field * vbi_fmt->count[0]) * 131 vbi_fmt->samples_per_line; 132 if (data->id == V4L2_SLICED_CAPTION_525) 133 vivid_vbi_gen_cc_raw(data, linebuf, vbi_fmt->sampling_rate); 134 else if (data->id == V4L2_SLICED_WSS_625) 135 vivid_vbi_gen_wss_raw(data, linebuf, vbi_fmt->sampling_rate); 136 else if (data->id == V4L2_SLICED_TELETEXT_B) 137 vivid_vbi_gen_teletext_raw(data, linebuf, vbi_fmt->sampling_rate); 138 } 139 } 140 141 static const u8 vivid_cc_sequence1[30] = { 142 0x14, 0x20, /* Resume Caption Loading */ 143 'H', 'e', 144 'l', 'l', 145 'o', ' ', 146 'w', 'o', 147 'r', 'l', 148 'd', '!', 149 0x14, 0x2f, /* End of Caption */ 150 }; 151 152 static const u8 vivid_cc_sequence2[30] = { 153 0x14, 0x20, /* Resume Caption Loading */ 154 'C', 'l', 155 'o', 's', 156 'e', 'd', 157 ' ', 'c', 158 'a', 'p', 159 't', 'i', 160 'o', 'n', 161 's', ' ', 162 't', 'e', 163 's', 't', 164 0x14, 0x2f, /* End of Caption */ 165 }; 166 167 static u8 calc_parity(u8 val) 168 { 169 return val | (parity8(val) ? 0 : 0x80); 170 } 171 172 static void vivid_vbi_gen_set_time_of_day(u8 *packet) 173 { 174 struct tm tm; 175 u8 checksum, i; 176 177 time64_to_tm(ktime_get_real_seconds(), 0, &tm); 178 packet[0] = calc_parity(0x07); 179 packet[1] = calc_parity(0x01); 180 packet[2] = calc_parity(0x40 | tm.tm_min); 181 packet[3] = calc_parity(0x40 | tm.tm_hour); 182 packet[4] = calc_parity(0x40 | tm.tm_mday); 183 if (tm.tm_mday == 1 && tm.tm_mon == 2 && 184 sys_tz.tz_minuteswest > tm.tm_min + tm.tm_hour * 60) 185 packet[4] = calc_parity(0x60 | tm.tm_mday); 186 packet[5] = calc_parity(0x40 | (1 + tm.tm_mon)); 187 packet[6] = calc_parity(0x40 | (1 + tm.tm_wday)); 188 packet[7] = calc_parity(0x40 | ((tm.tm_year - 90) & 0x3f)); 189 packet[8] = calc_parity(0x0f); 190 for (checksum = i = 0; i <= 8; i++) 191 checksum += packet[i] & 0x7f; 192 packet[9] = calc_parity(0x100 - checksum); 193 packet[10] = calc_parity(0x07); 194 packet[11] = calc_parity(0x04); 195 if (sys_tz.tz_minuteswest >= 0) 196 packet[12] = calc_parity(0x40 | ((sys_tz.tz_minuteswest / 60) & 0x1f)); 197 else 198 packet[12] = calc_parity(0x40 | ((24 + sys_tz.tz_minuteswest / 60) & 0x1f)); 199 packet[13] = calc_parity(0); 200 packet[14] = calc_parity(0x0f); 201 for (checksum = 0, i = 10; i <= 14; i++) 202 checksum += packet[i] & 0x7f; 203 packet[15] = calc_parity(0x100 - checksum); 204 } 205 206 static const u8 hamming[16] = { 207 0x15, 0x02, 0x49, 0x5e, 0x64, 0x73, 0x38, 0x2f, 208 0xd0, 0xc7, 0x8c, 0x9b, 0xa1, 0xb6, 0xfd, 0xea 209 }; 210 211 static void vivid_vbi_gen_teletext(u8 *packet, unsigned line, unsigned frame) 212 { 213 unsigned offset = 2; 214 unsigned i; 215 216 packet[0] = hamming[1 + ((line & 1) << 3)]; 217 packet[1] = hamming[line >> 1]; 218 memset(packet + 2, 0x20, 40); 219 if (line == 0) { 220 /* subcode */ 221 packet[2] = hamming[frame % 10]; 222 packet[3] = hamming[frame / 10]; 223 packet[4] = hamming[0]; 224 packet[5] = hamming[0]; 225 packet[6] = hamming[0]; 226 packet[7] = hamming[0]; 227 packet[8] = hamming[0]; 228 packet[9] = hamming[1]; 229 offset = 10; 230 } 231 packet += offset; 232 memcpy(packet, "Page: 100 Row: 10", 17); 233 packet[7] = '0' + frame / 10; 234 packet[8] = '0' + frame % 10; 235 packet[15] = '0' + line / 10; 236 packet[16] = '0' + line % 10; 237 for (i = 0; i < 42 - offset; i++) 238 packet[i] = calc_parity(packet[i]); 239 } 240 241 void vivid_vbi_gen_sliced(struct vivid_vbi_gen_data *vbi, 242 bool is_60hz, unsigned seqnr) 243 { 244 struct v4l2_sliced_vbi_data *data0 = vbi->data; 245 struct v4l2_sliced_vbi_data *data1 = vbi->data + 1; 246 unsigned frame = seqnr % 60; 247 248 memset(vbi->data, 0, sizeof(vbi->data)); 249 250 if (!is_60hz) { 251 unsigned i; 252 253 for (i = 0; i <= 11; i++) { 254 data0->id = V4L2_SLICED_TELETEXT_B; 255 data0->line = 7 + i; 256 vivid_vbi_gen_teletext(data0->data, i, frame); 257 data0++; 258 } 259 data0->id = V4L2_SLICED_WSS_625; 260 data0->line = 23; 261 /* 4x3 video aspect ratio */ 262 data0->data[0] = 0x08; 263 data0++; 264 for (i = 0; i <= 11; i++) { 265 data0->id = V4L2_SLICED_TELETEXT_B; 266 data0->field = 1; 267 data0->line = 7 + i; 268 vivid_vbi_gen_teletext(data0->data, 12 + i, frame); 269 data0++; 270 } 271 return; 272 } 273 274 data0->id = V4L2_SLICED_CAPTION_525; 275 data0->line = 21; 276 data1->id = V4L2_SLICED_CAPTION_525; 277 data1->field = 1; 278 data1->line = 21; 279 280 if (frame < 15) { 281 data0->data[0] = calc_parity(vivid_cc_sequence1[2 * frame]); 282 data0->data[1] = calc_parity(vivid_cc_sequence1[2 * frame + 1]); 283 } else if (frame >= 30 && frame < 45) { 284 frame -= 30; 285 data0->data[0] = calc_parity(vivid_cc_sequence2[2 * frame]); 286 data0->data[1] = calc_parity(vivid_cc_sequence2[2 * frame + 1]); 287 } else { 288 data0->data[0] = calc_parity(0); 289 data0->data[1] = calc_parity(0); 290 } 291 292 frame = seqnr % (30 * 60); 293 switch (frame) { 294 case 0: 295 vivid_vbi_gen_set_time_of_day(vbi->time_of_day_packet); 296 fallthrough; 297 case 1 ... 7: 298 data1->data[0] = vbi->time_of_day_packet[frame * 2]; 299 data1->data[1] = vbi->time_of_day_packet[frame * 2 + 1]; 300 break; 301 default: 302 data1->data[0] = calc_parity(0); 303 data1->data[1] = calc_parity(0); 304 break; 305 } 306 } 307