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
wss_insert(u8 * wss,u32 val,unsigned size)16 static void wss_insert(u8 *wss, u32 val, unsigned size)
17 {
18 while (size--)
19 *wss++ = (val & (1 << size)) ? 0xc0 : 0x10;
20 }
21
vivid_vbi_gen_wss_raw(const struct v4l2_sliced_vbi_data * data,u8 * buf,unsigned sampling_rate)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
vivid_vbi_gen_teletext_raw(const struct v4l2_sliced_vbi_data * data,u8 * buf,unsigned sampling_rate)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
cc_insert(u8 * cc,u8 ch)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
vivid_vbi_gen_cc_raw(const struct v4l2_sliced_vbi_data * data,u8 * buf,unsigned sampling_rate)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
vivid_vbi_gen_raw(const struct vivid_vbi_gen_data * vbi,const struct v4l2_vbi_format * vbi_fmt,u8 * buf)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
calc_parity(u8 val)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
vivid_vbi_gen_set_time_of_day(u8 * packet)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 checksum = 0;
198 packet[10] = calc_parity(0x07);
199 packet[11] = calc_parity(0x04);
200 if (sys_tz.tz_minuteswest >= 0)
201 packet[12] = calc_parity(0x40 | ((sys_tz.tz_minuteswest / 60) & 0x1f));
202 else
203 packet[12] = calc_parity(0x40 | ((24 + sys_tz.tz_minuteswest / 60) & 0x1f));
204 packet[13] = calc_parity(0);
205 packet[14] = calc_parity(0x0f);
206 for (checksum = 0, i = 10; i <= 14; i++)
207 checksum += packet[i] & 0x7f;
208 packet[15] = calc_parity(0x100 - checksum);
209 }
210
211 static const u8 hamming[16] = {
212 0x15, 0x02, 0x49, 0x5e, 0x64, 0x73, 0x38, 0x2f,
213 0xd0, 0xc7, 0x8c, 0x9b, 0xa1, 0xb6, 0xfd, 0xea
214 };
215
vivid_vbi_gen_teletext(u8 * packet,unsigned line,unsigned frame)216 static void vivid_vbi_gen_teletext(u8 *packet, unsigned line, unsigned frame)
217 {
218 unsigned offset = 2;
219 unsigned i;
220
221 packet[0] = hamming[1 + ((line & 1) << 3)];
222 packet[1] = hamming[line >> 1];
223 memset(packet + 2, 0x20, 40);
224 if (line == 0) {
225 /* subcode */
226 packet[2] = hamming[frame % 10];
227 packet[3] = hamming[frame / 10];
228 packet[4] = hamming[0];
229 packet[5] = hamming[0];
230 packet[6] = hamming[0];
231 packet[7] = hamming[0];
232 packet[8] = hamming[0];
233 packet[9] = hamming[1];
234 offset = 10;
235 }
236 packet += offset;
237 memcpy(packet, "Page: 100 Row: 10", 17);
238 packet[7] = '0' + frame / 10;
239 packet[8] = '0' + frame % 10;
240 packet[15] = '0' + line / 10;
241 packet[16] = '0' + line % 10;
242 for (i = 0; i < 42 - offset; i++)
243 packet[i] = calc_parity(packet[i]);
244 }
245
vivid_vbi_gen_sliced(struct vivid_vbi_gen_data * vbi,bool is_60hz,unsigned seqnr)246 void vivid_vbi_gen_sliced(struct vivid_vbi_gen_data *vbi,
247 bool is_60hz, unsigned seqnr)
248 {
249 struct v4l2_sliced_vbi_data *data0 = vbi->data;
250 struct v4l2_sliced_vbi_data *data1 = vbi->data + 1;
251 unsigned frame = seqnr % 60;
252
253 memset(vbi->data, 0, sizeof(vbi->data));
254
255 if (!is_60hz) {
256 unsigned i;
257
258 for (i = 0; i <= 11; i++) {
259 data0->id = V4L2_SLICED_TELETEXT_B;
260 data0->line = 7 + i;
261 vivid_vbi_gen_teletext(data0->data, i, frame);
262 data0++;
263 }
264 data0->id = V4L2_SLICED_WSS_625;
265 data0->line = 23;
266 /* 4x3 video aspect ratio */
267 data0->data[0] = 0x08;
268 data0++;
269 for (i = 0; i <= 11; i++) {
270 data0->id = V4L2_SLICED_TELETEXT_B;
271 data0->field = 1;
272 data0->line = 7 + i;
273 vivid_vbi_gen_teletext(data0->data, 12 + i, frame);
274 data0++;
275 }
276 return;
277 }
278
279 data0->id = V4L2_SLICED_CAPTION_525;
280 data0->line = 21;
281 data1->id = V4L2_SLICED_CAPTION_525;
282 data1->field = 1;
283 data1->line = 21;
284
285 if (frame < 15) {
286 data0->data[0] = calc_parity(vivid_cc_sequence1[2 * frame]);
287 data0->data[1] = calc_parity(vivid_cc_sequence1[2 * frame + 1]);
288 } else if (frame >= 30 && frame < 45) {
289 frame -= 30;
290 data0->data[0] = calc_parity(vivid_cc_sequence2[2 * frame]);
291 data0->data[1] = calc_parity(vivid_cc_sequence2[2 * frame + 1]);
292 } else {
293 data0->data[0] = calc_parity(0);
294 data0->data[1] = calc_parity(0);
295 }
296
297 frame = seqnr % (30 * 60);
298 switch (frame) {
299 case 0:
300 vivid_vbi_gen_set_time_of_day(vbi->time_of_day_packet);
301 /* fall through */
302 case 1 ... 7:
303 data1->data[0] = vbi->time_of_day_packet[frame * 2];
304 data1->data[1] = vbi->time_of_day_packet[frame * 2 + 1];
305 break;
306 default:
307 data1->data[0] = calc_parity(0);
308 data1->data[1] = calc_parity(0);
309 break;
310 }
311 }
312
