LXR linux/drivers/media/platform/vivid/vivid-vbi-gen.c

   1/*
   2 * vivid-vbi-gen.c - vbi generator support functions.
   3 *
   4 * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
   5 *
   6 * This program is free software; you may redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; version 2 of the License.
   9 *
  10 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  11 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  12 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  13 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  14 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  15 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  16 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  17 * SOFTWARE.
  18 */
  19
  20#include <linux/errno.h>
  21#include <linux/kernel.h>
  22#include <linux/ktime.h>
  23#include <linux/string.h>
  24#include <linux/videodev2.h>
  25
  26#include "vivid-vbi-gen.h"
  27
  28static void wss_insert(u8 *wss, u32 val, unsigned size)
  29{
  30        while (size--)
  31                *wss++ = (val & (1 << size)) ? 0xc0 : 0x10;
  32}
  33
  34static void vivid_vbi_gen_wss_raw(const struct v4l2_sliced_vbi_data *data,
  35                u8 *buf, unsigned sampling_rate)
  36{
  37        const unsigned rate = 5000000;  /* WSS has a 5 MHz transmission rate */
  38        u8 wss[29 + 24 + 24 + 24 + 18 + 18] = { 0 };
  39        const unsigned zero = 0x07;
  40        const unsigned one = 0x38;
  41        unsigned bit = 0;
  42        u16 wss_data;
  43        int i;
  44
  45        wss_insert(wss + bit, 0x1f1c71c7, 29); bit += 29;
  46        wss_insert(wss + bit, 0x1e3c1f, 24); bit += 24;
  47
  48        wss_data = (data->data[1] << 8) | data->data[0];
  49        for (i = 0; i <= 13; i++, bit += 6)
  50                wss_insert(wss + bit, (wss_data & (1 << i)) ? one : zero, 6);
  51
  52        for (i = 0, bit = 0; bit < sizeof(wss); bit++) {
  53                unsigned n = ((bit + 1) * sampling_rate) / rate;
  54
  55                while (i < n)
  56                        buf[i++] = wss[bit];
  57        }
  58}
  59
  60static void vivid_vbi_gen_teletext_raw(const struct v4l2_sliced_vbi_data *data,
  61                u8 *buf, unsigned sampling_rate)
  62{
  63        const unsigned rate = 6937500 / 10;     /* Teletext has a 6.9375 MHz transmission rate */
  64        u8 teletext[45] = { 0x55, 0x55, 0x27 };
  65        unsigned bit = 0;
  66        int i;
  67
  68        memcpy(teletext + 3, data->data, sizeof(teletext) - 3);
  69        /* prevents 32 bit overflow */
  70        sampling_rate /= 10;
  71
  72        for (i = 0, bit = 0; bit < sizeof(teletext) * 8; bit++) {
  73                unsigned n = ((bit + 1) * sampling_rate) / rate;
  74                u8 val = (teletext[bit / 8] & (1 << (bit & 7))) ? 0xc0 : 0x10;
  75
  76                while (i < n)
  77                        buf[i++] = val;
  78        }
  79}
  80
  81static void cc_insert(u8 *cc, u8 ch)
  82{
  83        unsigned tot = 0;
  84        unsigned i;
  85
  86        for (i = 0; i < 7; i++) {
  87                cc[2 * i] = cc[2 * i + 1] = (ch & (1 << i)) ? 1 : 0;
  88                tot += cc[2 * i];
  89        }
  90        cc[14] = cc[15] = !(tot & 1);
  91}
  92
  93#define CC_PREAMBLE_BITS (14 + 4 + 2)
  94
  95static void vivid_vbi_gen_cc_raw(const struct v4l2_sliced_vbi_data *data,
  96                u8 *buf, unsigned sampling_rate)
  97{
  98        const unsigned rate = 1000000;  /* CC has a 1 MHz transmission rate */
  99
 100        u8 cc[CC_PREAMBLE_BITS + 2 * 16] = {
 101                /* Clock run-in: 7 cycles */
 102                0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
 103                /* 2 cycles of 0 */
 104                0, 0, 0, 0,
 105                /* Start bit of 1 (each bit is two cycles) */
 106                1, 1
 107        };
 108        unsigned bit, i;
 109
 110        cc_insert(cc + CC_PREAMBLE_BITS, data->data[0]);
 111        cc_insert(cc + CC_PREAMBLE_BITS + 16, data->data[1]);
 112
 113        for (i = 0, bit = 0; bit < sizeof(cc); bit++) {
 114                unsigned n = ((bit + 1) * sampling_rate) / rate;
 115
 116                while (i < n)
 117                        buf[i++] = cc[bit] ? 0xc0 : 0x10;
 118        }
 119}
 120
 121void vivid_vbi_gen_raw(const struct vivid_vbi_gen_data *vbi,
 122                const struct v4l2_vbi_format *vbi_fmt, u8 *buf)
 123{
 124        unsigned idx;
 125
 126        for (idx = 0; idx < 25; idx++) {
 127                const struct v4l2_sliced_vbi_data *data = vbi->data + idx;
 128                unsigned start_2nd_field;
 129                unsigned line = data->line;
 130                u8 *linebuf = buf;
 131
 132                start_2nd_field = (data->id & V4L2_SLICED_VBI_525) ? 263 : 313;
 133                if (data->field)
 134                        line += start_2nd_field;
 135                line -= vbi_fmt->start[data->field];
 136
 137                if (vbi_fmt->flags & V4L2_VBI_INTERLACED)
 138                        linebuf += (line * 2 + data->field) *
 139                                vbi_fmt->samples_per_line;
 140                else
 141                        linebuf += (line + data->field * vbi_fmt->count[0]) *
 142                                vbi_fmt->samples_per_line;
 143                if (data->id == V4L2_SLICED_CAPTION_525)
 144                        vivid_vbi_gen_cc_raw(data, linebuf, vbi_fmt->sampling_rate);
 145                else if (data->id == V4L2_SLICED_WSS_625)
 146                        vivid_vbi_gen_wss_raw(data, linebuf, vbi_fmt->sampling_rate);
 147                else if (data->id == V4L2_SLICED_TELETEXT_B)
 148                        vivid_vbi_gen_teletext_raw(data, linebuf, vbi_fmt->sampling_rate);
 149        }
 150}
 151
 152static const u8 vivid_cc_sequence1[30] = {
 153        0x14, 0x20,     /* Resume Caption Loading */
 154        'H',  'e',
 155        'l',  'l',
 156        'o',  ' ',
 157        'w',  'o',
 158        'r',  'l',
 159        'd',  '!',
 160        0x14, 0x2f,     /* End of Caption */
 161};
 162
 163static const u8 vivid_cc_sequence2[30] = {
 164        0x14, 0x20,     /* Resume Caption Loading */
 165        'C',  'l',
 166        'o',  's',
 167        'e',  'd',
 168        ' ',  'c',
 169        'a',  'p',
 170        't',  'i',
 171        'o',  'n',
 172        's',  ' ',
 173        't',  'e',
 174        's',  't',
 175        0x14, 0x2f,     /* End of Caption */
 176};
 177
 178static u8 calc_parity(u8 val)
 179{
 180        unsigned i;
 181        unsigned tot = 0;
 182
 183        for (i = 0; i < 7; i++)
 184                tot += (val & (1 << i)) ? 1 : 0;
 185        return val | ((tot & 1) ? 0 : 0x80);
 186}
 187
 188static void vivid_vbi_gen_set_time_of_day(u8 *packet)
 189{
 190        struct tm tm;
 191        u8 checksum, i;
 192
 193        time64_to_tm(ktime_get_real_seconds(), 0, &tm);
 194        packet[0] = calc_parity(0x07);
 195        packet[1] = calc_parity(0x01);
 196        packet[2] = calc_parity(0x40 | tm.tm_min);
 197        packet[3] = calc_parity(0x40 | tm.tm_hour);
 198        packet[4] = calc_parity(0x40 | tm.tm_mday);
 199        if (tm.tm_mday == 1 && tm.tm_mon == 2 &&
 200            sys_tz.tz_minuteswest > tm.tm_min + tm.tm_hour * 60)
 201                packet[4] = calc_parity(0x60 | tm.tm_mday);
 202        packet[5] = calc_parity(0x40 | (1 + tm.tm_mon));
 203        packet[6] = calc_parity(0x40 | (1 + tm.tm_wday));
 204        packet[7] = calc_parity(0x40 | ((tm.tm_year - 90) & 0x3f));
 205        packet[8] = calc_parity(0x0f);
 206        for (checksum = i = 0; i <= 8; i++)
 207                checksum += packet[i] & 0x7f;
 208        packet[9] = calc_parity(0x100 - checksum);
 209        checksum = 0;
 210        packet[10] = calc_parity(0x07);
 211        packet[11] = calc_parity(0x04);
 212        if (sys_tz.tz_minuteswest >= 0)
 213                packet[12] = calc_parity(0x40 | ((sys_tz.tz_minuteswest / 60) & 0x1f));
 214        else
 215                packet[12] = calc_parity(0x40 | ((24 + sys_tz.tz_minuteswest / 60) & 0x1f));
 216        packet[13] = calc_parity(0);
 217        packet[14] = calc_parity(0x0f);
 218        for (checksum = 0, i = 10; i <= 14; i++)
 219                checksum += packet[i] & 0x7f;
 220        packet[15] = calc_parity(0x100 - checksum);
 221}
 222
 223static const u8 hamming[16] = {
 224        0x15, 0x02, 0x49, 0x5e, 0x64, 0x73, 0x38, 0x2f,
 225        0xd0, 0xc7, 0x8c, 0x9b, 0xa1, 0xb6, 0xfd, 0xea
 226};
 227
 228static void vivid_vbi_gen_teletext(u8 *packet, unsigned line, unsigned frame)
 229{
 230        unsigned offset = 2;
 231        unsigned i;
 232
 233        packet[0] = hamming[1 + ((line & 1) << 3)];
 234        packet[1] = hamming[line >> 1];
 235        memset(packet + 2, 0x20, 40);
 236        if (line == 0) {
 237                /* subcode */
 238                packet[2] = hamming[frame % 10];
 239                packet[3] = hamming[frame / 10];
 240                packet[4] = hamming[0];
 241                packet[5] = hamming[0];
 242                packet[6] = hamming[0];
 243                packet[7] = hamming[0];
 244                packet[8] = hamming[0];
 245                packet[9] = hamming[1];
 246                offset = 10;
 247        }
 248        packet += offset;
 249        memcpy(packet, "Page: 100 Row: 10", 17);
 250        packet[7] = '0' + frame / 10;
 251        packet[8] = '0' + frame % 10;
 252        packet[15] = '0' + line / 10;
 253        packet[16] = '0' + line % 10;
 254        for (i = 0; i < 42 - offset; i++)
 255                packet[i] = calc_parity(packet[i]);
 256}
 257
 258void vivid_vbi_gen_sliced(struct vivid_vbi_gen_data *vbi,
 259                bool is_60hz, unsigned seqnr)
 260{
 261        struct v4l2_sliced_vbi_data *data0 = vbi->data;
 262        struct v4l2_sliced_vbi_data *data1 = vbi->data + 1;
 263        unsigned frame = seqnr % 60;
 264
 265        memset(vbi->data, 0, sizeof(vbi->data));
 266
 267        if (!is_60hz) {
 268                unsigned i;
 269
 270                for (i = 0; i <= 11; i++) {
 271                        data0->id = V4L2_SLICED_TELETEXT_B;
 272                        data0->line = 7 + i;
 273                        vivid_vbi_gen_teletext(data0->data, i, frame);
 274                        data0++;
 275                }
 276                data0->id = V4L2_SLICED_WSS_625;
 277                data0->line = 23;
 278                /* 4x3 video aspect ratio */
 279                data0->data[0] = 0x08;
 280                data0++;
 281                for (i = 0; i <= 11; i++) {
 282                        data0->id = V4L2_SLICED_TELETEXT_B;
 283                        data0->field = 1;
 284                        data0->line = 7 + i;
 285                        vivid_vbi_gen_teletext(data0->data, 12 + i, frame);
 286                        data0++;
 287                }
 288                return;
 289        }
 290
 291        data0->id = V4L2_SLICED_CAPTION_525;
 292        data0->line = 21;
 293        data1->id = V4L2_SLICED_CAPTION_525;
 294        data1->field = 1;
 295        data1->line = 21;
 296
 297        if (frame < 15) {
 298                data0->data[0] = calc_parity(vivid_cc_sequence1[2 * frame]);
 299                data0->data[1] = calc_parity(vivid_cc_sequence1[2 * frame + 1]);
 300        } else if (frame >= 30 && frame < 45) {
 301                frame -= 30;
 302                data0->data[0] = calc_parity(vivid_cc_sequence2[2 * frame]);
 303                data0->data[1] = calc_parity(vivid_cc_sequence2[2 * frame + 1]);
 304        } else {
 305                data0->data[0] = calc_parity(0);
 306                data0->data[1] = calc_parity(0);
 307        }
 308
 309        frame = seqnr % (30 * 60);
 310        switch (frame) {
 311        case 0:
 312                vivid_vbi_gen_set_time_of_day(vbi->time_of_day_packet);
 313                /* fall through */
 314        case 1 ... 7:
 315                data1->data[0] = vbi->time_of_day_packet[frame * 2];
 316                data1->data[1] = vbi->time_of_day_packet[frame * 2 + 1];
 317                break;
 318        default:
 319                data1->data[0] = calc_parity(0);
 320                data1->data[1] = calc_parity(0);
 321                break;
 322        }
 323}
 324