drivers/media/test-drivers/vidtv/vidtv_demod.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * The Virtual DVB test driver serves as a reference DVB driver and helps
   4  * validate the existing APIs in the media subsystem. It can also aid
   5  * developers working on userspace applications.
   6  *
   7  * Copyright (C) 2020 Daniel W. S. Almeida
   8  * Based on the example driver written by Emard <emard@softhome.net>
   9  */
  10
  11 #include <linux/errno.h>
  12 #include <linux/i2c.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/printk.h>
  17 #include <linux/random.h>
  18 #include <linux/ratelimit.h>
  19 #include <linux/slab.h>
  20 #include <linux/string.h>
  21 #include <linux/workqueue.h>
  22
  23 #include <media/dvb_frontend.h>
  24
  25 #include "vidtv_demod.h"
  26
  27 #define POLL_THRD_TIME 2000 /* ms */
  28
  29 static const struct vidtv_demod_cnr_to_qual_s vidtv_demod_c_cnr_2_qual[] = {
  30         /* from libdvbv5 source code, in milli db */
  31         { QAM_256, FEC_NONE,  34000, 38000},
  32         { QAM_64,  FEC_NONE,  30000, 34000},
  33 };
  34
  35 static const struct vidtv_demod_cnr_to_qual_s vidtv_demod_s_cnr_2_qual[] = {
  36         /* from libdvbv5 source code, in milli db */
  37         { QPSK, FEC_1_2,  7000, 10000},
  38         { QPSK, FEC_2_3,  9000, 12000},
  39         { QPSK, FEC_3_4, 10000, 13000},
  40         { QPSK, FEC_5_6, 11000, 14000},
  41         { QPSK, FEC_7_8, 12000, 15000},
  42 };
  43
  44 static const struct vidtv_demod_cnr_to_qual_s vidtv_demod_s2_cnr_2_qual[] = {
  45         /* from libdvbv5 source code, in milli db */
  46         { QPSK,  FEC_1_2,   9000,  12000},
  47         { QPSK,  FEC_2_3,  11000,  14000},
  48         { QPSK,  FEC_3_4,  12000,  15000},
  49         { QPSK,  FEC_5_6,  12000,  15000},
  50         { QPSK,  FEC_8_9,  13000,  16000},
  51         { QPSK,  FEC_9_10, 13500,  16500},
  52         { PSK_8, FEC_2_3,  14500,  17500},
  53         { PSK_8, FEC_3_4,  16000,  19000},
  54         { PSK_8, FEC_5_6,  17500,  20500},
  55         { PSK_8, FEC_8_9,  19000,  22000},
  56 };
  57
  58 static const struct vidtv_demod_cnr_to_qual_s vidtv_demod_t_cnr_2_qual[] = {
  59         /* from libdvbv5 source code, in milli db*/
  60         {   QPSK, FEC_1_2,  4100,  5900},
  61         {   QPSK, FEC_2_3,  6100,  9600},
  62         {   QPSK, FEC_3_4,  7200, 12400},
  63         {   QPSK, FEC_5_6,  8500, 15600},
  64         {   QPSK, FEC_7_8,  9200, 17500},
  65         { QAM_16, FEC_1_2,  9800, 11800},
  66         { QAM_16, FEC_2_3, 12100, 15300},
  67         { QAM_16, FEC_3_4, 13400, 18100},
  68         { QAM_16, FEC_5_6, 14800, 21300},
  69         { QAM_16, FEC_7_8, 15700, 23600},
  70         { QAM_64, FEC_1_2, 14000, 16000},
  71         { QAM_64, FEC_2_3, 19900, 25400},
  72         { QAM_64, FEC_3_4, 24900, 27900},
  73         { QAM_64, FEC_5_6, 21300, 23300},
  74         { QAM_64, FEC_7_8, 22000, 24000},
  75 };
  76
  77 static const struct vidtv_demod_cnr_to_qual_s *vidtv_match_cnr_s(struct dvb_frontend *fe)
  78 {
  79         const struct vidtv_demod_cnr_to_qual_s *cnr2qual = NULL;
  80         struct device *dev = fe->dvb->device;
  81         struct dtv_frontend_properties *c;
  82         u32 array_size = 0;
  83         u32 i;
  84
  85         c = &fe->dtv_property_cache;
  86
  87         switch (c->delivery_system) {
  88         case SYS_DVBT:
  89         case SYS_DVBT2:
  90                 cnr2qual   = vidtv_demod_t_cnr_2_qual;
  91                 array_size = ARRAY_SIZE(vidtv_demod_t_cnr_2_qual);
  92                 break;
  93
  94         case SYS_DVBS:
  95                 cnr2qual   = vidtv_demod_s_cnr_2_qual;
  96                 array_size = ARRAY_SIZE(vidtv_demod_s_cnr_2_qual);
  97                 break;
  98
  99         case SYS_DVBS2:
 100                 cnr2qual   = vidtv_demod_s2_cnr_2_qual;
 101                 array_size = ARRAY_SIZE(vidtv_demod_s2_cnr_2_qual);
 102                 break;
 103
 104         case SYS_DVBC_ANNEX_A:
 105                 cnr2qual   = vidtv_demod_c_cnr_2_qual;
 106                 array_size = ARRAY_SIZE(vidtv_demod_c_cnr_2_qual);
 107                 break;
 108
 109         default:
 110                 dev_warn_ratelimited(dev,
 111                                      "%s: unsupported delivery system: %u\n",
 112                                      __func__,
 113                                      c->delivery_system);
 114                 break;
 115         }
 116
 117         for (i = 0; i < array_size; i++)
 118                 if (cnr2qual[i].modulation == c->modulation &&
 119                     cnr2qual[i].fec == c->fec_inner)
 120                         return &cnr2qual[i];
 121
 122         return NULL; /* not found */
 123 }
 124
 125 static void vidtv_clean_stats(struct dvb_frontend *fe)
 126 {
 127         struct dtv_frontend_properties *c = &fe->dtv_property_cache;
 128
 129         /* Fill the length of each status counter */
 130
 131         /* Signal is always available */
 132         c->strength.len = 1;
 133         c->strength.stat[0].scale = FE_SCALE_DECIBEL;
 134         c->strength.stat[0].svalue = 0;
 135
 136         /* Usually available only after Viterbi lock */
 137         c->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 138         c->cnr.stat[0].svalue = 0;
 139         c->cnr.len = 1;
 140
 141         /* Those depends on full lock */
 142         c->pre_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 143         c->pre_bit_error.stat[0].uvalue = 0;
 144         c->pre_bit_error.len = 1;
 145         c->pre_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 146         c->pre_bit_count.stat[0].uvalue = 0;
 147         c->pre_bit_count.len = 1;
 148         c->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 149         c->post_bit_error.stat[0].uvalue = 0;
 150         c->post_bit_error.len = 1;
 151         c->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 152         c->post_bit_count.stat[0].uvalue = 0;
 153         c->post_bit_count.len = 1;
 154         c->block_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 155         c->block_error.stat[0].uvalue = 0;
 156         c->block_error.len = 1;
 157         c->block_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 158         c->block_count.stat[0].uvalue = 0;
 159         c->block_count.len = 1;
 160 }
 161
 162 static void vidtv_demod_update_stats(struct dvb_frontend *fe)
 163 {
 164         struct dtv_frontend_properties *c = &fe->dtv_property_cache;
 165         struct vidtv_demod_state *state = fe->demodulator_priv;
 166         u32 scale;
 167
 168         if (state->status & FE_HAS_LOCK) {
 169                 scale = FE_SCALE_COUNTER;
 170                 c->cnr.stat[0].scale = FE_SCALE_DECIBEL;
 171         } else {
 172                 scale = FE_SCALE_NOT_AVAILABLE;
 173                 c->cnr.stat[0].scale = scale;
 174         }
 175
 176         c->pre_bit_error.stat[0].scale = scale;
 177         c->pre_bit_count.stat[0].scale = scale;
 178         c->post_bit_error.stat[0].scale = scale;
 179         c->post_bit_count.stat[0].scale = scale;
 180         c->block_error.stat[0].scale = scale;
 181         c->block_count.stat[0].scale = scale;
 182
 183         /*
 184          * Add a 0.5% of randomness at the signal strength and CNR,
 185          * and make them different, as we want to have something closer
 186          * to a real case scenario.
 187          *
 188          * Also, usually, signal strength is a negative number in dBm.
 189          */
 190         c->strength.stat[0].svalue = state->tuner_cnr;
 191         c->strength.stat[0].svalue -= prandom_u32_max(state->tuner_cnr / 50);
 192         c->strength.stat[0].svalue -= 68000; /* Adjust to a better range */
 193
 194         c->cnr.stat[0].svalue = state->tuner_cnr;
 195         c->cnr.stat[0].svalue -= prandom_u32_max(state->tuner_cnr / 50);
 196 }
 197
 198 static int vidtv_demod_read_status(struct dvb_frontend *fe,
 199                                    enum fe_status *status)
 200 {
 201         struct vidtv_demod_state *state = fe->demodulator_priv;
 202         const struct vidtv_demod_cnr_to_qual_s *cnr2qual = NULL;
 203         struct vidtv_demod_config *config = &state->config;
 204         u16 snr = 0;
 205
 206         /* Simulate random lost of signal due to a bad-tuned channel */
 207         cnr2qual = vidtv_match_cnr_s(&state->frontend);
 208
 209         if (cnr2qual && state->tuner_cnr < cnr2qual->cnr_good &&
 210             state->frontend.ops.tuner_ops.get_rf_strength) {
 211                 state->frontend.ops.tuner_ops.get_rf_strength(&state->frontend,
 212                                                               &snr);
 213
 214                 if (snr < cnr2qual->cnr_ok) {
 215                         /* eventually lose the TS lock */
 216                         if (prandom_u32_max(100) < config->drop_tslock_prob_on_low_snr)
 217                                 state->status = 0;
 218                 } else {
 219                         /* recover if the signal improves */
 220                         if (prandom_u32_max(100) <
 221                             config->recover_tslock_prob_on_good_snr)
 222                                 state->status = FE_HAS_SIGNAL  |
 223                                                 FE_HAS_CARRIER |
 224                                                 FE_HAS_VITERBI |
 225                                                 FE_HAS_SYNC    |
 226                                                 FE_HAS_LOCK;
 227                 }
 228         }
 229
 230         vidtv_demod_update_stats(&state->frontend);
 231
 232         *status = state->status;
 233
 234         return 0;
 235 }
 236
 237 static int vidtv_demod_read_signal_strength(struct dvb_frontend *fe,
 238                                             u16 *strength)
 239 {
 240         struct dtv_frontend_properties *c = &fe->dtv_property_cache;
 241
 242         *strength = c->strength.stat[0].uvalue;
 243
 244         return 0;
 245 }
 246
 247 /*
 248  * NOTE:
 249  * This is implemented here just to be used as an example for real
 250  * demod drivers.
 251  *
 252  * Should only be implemented if it actually reads something from the hardware.
 253  * Also, it should check for the locks, in order to avoid report wrong data
 254  * to userspace.
 255  */
 256 static int vidtv_demod_get_frontend(struct dvb_frontend *fe,
 257                                     struct dtv_frontend_properties *p)
 258 {
 259         return 0;
 260 }
 261
 262 static int vidtv_demod_set_frontend(struct dvb_frontend *fe)
 263 {
 264         struct vidtv_demod_state *state = fe->demodulator_priv;
 265         u32 tuner_status = 0;
 266         int ret;
 267
 268         if (!fe->ops.tuner_ops.set_params)
 269                 return 0;
 270
 271         fe->ops.tuner_ops.set_params(fe);
 272
 273         /* store the CNR returned by the tuner */
 274         ret = fe->ops.tuner_ops.get_rf_strength(fe, &state->tuner_cnr);
 275         if (ret < 0)
 276                 return ret;
 277
 278         fe->ops.tuner_ops.get_status(fe, &tuner_status);
 279         state->status = (state->tuner_cnr > 0) ?  FE_HAS_SIGNAL  |
 280                                                     FE_HAS_CARRIER |
 281                                                     FE_HAS_VITERBI |
 282                                                     FE_HAS_SYNC    |
 283                                                     FE_HAS_LOCK  :
 284                                                     0;
 285
 286         vidtv_demod_update_stats(fe);
 287
 288         if (fe->ops.i2c_gate_ctrl)
 289                 fe->ops.i2c_gate_ctrl(fe, 0);
 290
 291         return 0;
 292 }
 293
 294 /*
 295  * NOTE:
 296  * This is implemented here just to be used as an example for real
 297  * demod drivers.
 298  *
 299  * Should only be implemented if the demod has support for DVB-S or DVB-S2
 300  */
 301 static int vidtv_demod_set_tone(struct dvb_frontend *fe,
 302                                 enum fe_sec_tone_mode tone)
 303 {
 304         return 0;
 305 }
 306
 307 /*
 308  * NOTE:
 309  * This is implemented here just to be used as an example for real
 310  * demod drivers.
 311  *
 312  * Should only be implemented if the demod has support for DVB-S or DVB-S2
 313  */
 314 static int vidtv_demod_set_voltage(struct dvb_frontend *fe,
 315                                    enum fe_sec_voltage voltage)
 316 {
 317         return 0;
 318 }
 319
 320 /*
 321  * NOTE:
 322  * This is implemented here just to be used as an example for real
 323  * demod drivers.
 324  *
 325  * Should only be implemented if the demod has support for DVB-S or DVB-S2
 326  */
 327 static int vidtv_send_diseqc_msg(struct dvb_frontend *fe,
 328                                  struct dvb_diseqc_master_cmd *cmd)
 329 {
 330         return 0;
 331 }
 332
 333 /*
 334  * NOTE:
 335  * This is implemented here just to be used as an example for real
 336  * demod drivers.
 337  *
 338  * Should only be implemented if the demod has support for DVB-S or DVB-S2
 339  */
 340 static int vidtv_diseqc_send_burst(struct dvb_frontend *fe,
 341                                    enum fe_sec_mini_cmd burst)
 342 {
 343         return 0;
 344 }
 345
 346 static void vidtv_demod_release(struct dvb_frontend *fe)
 347 {
 348         struct vidtv_demod_state *state = fe->demodulator_priv;
 349
 350         kfree(state);
 351 }
 352
 353 static const struct dvb_frontend_ops vidtv_demod_ops = {
 354         .delsys = {
 355                 SYS_DVBT,
 356                 SYS_DVBT2,
 357                 SYS_DVBC_ANNEX_A,
 358                 SYS_DVBS,
 359                 SYS_DVBS2,
 360         },
 361
 362         .info = {
 363                 .name                   = "Dummy demod for DVB-T/T2/C/S/S2",
 364                 .frequency_min_hz       = 51 * MHz,
 365                 .frequency_max_hz       = 2150 * MHz,
 366                 .frequency_stepsize_hz  = 62500,
 367                 .frequency_tolerance_hz = 29500 * kHz,
 368                 .symbol_rate_min        = 1000000,
 369                 .symbol_rate_max        = 45000000,
 370
 371                 .caps = FE_CAN_FEC_1_2 |
 372                         FE_CAN_FEC_2_3 |
 373                         FE_CAN_FEC_3_4 |
 374                         FE_CAN_FEC_4_5 |
 375                         FE_CAN_FEC_5_6 |
 376                         FE_CAN_FEC_6_7 |
 377                         FE_CAN_FEC_7_8 |
 378                         FE_CAN_FEC_8_9 |
 379                         FE_CAN_QAM_16 |
 380                         FE_CAN_QAM_64 |
 381                         FE_CAN_QAM_32 |
 382                         FE_CAN_QAM_128 |
 383                         FE_CAN_QAM_256 |
 384                         FE_CAN_QAM_AUTO |
 385                         FE_CAN_QPSK |
 386                         FE_CAN_FEC_AUTO |
 387                         FE_CAN_INVERSION_AUTO |
 388                         FE_CAN_TRANSMISSION_MODE_AUTO |
 389                         FE_CAN_GUARD_INTERVAL_AUTO |
 390                         FE_CAN_HIERARCHY_AUTO,
 391         },
 392
 393         .release = vidtv_demod_release,
 394
 395         .set_frontend = vidtv_demod_set_frontend,
 396         .get_frontend = vidtv_demod_get_frontend,
 397
 398         .read_status          = vidtv_demod_read_status,
 399         .read_signal_strength = vidtv_demod_read_signal_strength,
 400
 401         /* For DVB-S/S2 */
 402         .set_voltage            = vidtv_demod_set_voltage,
 403         .set_tone               = vidtv_demod_set_tone,
 404         .diseqc_send_master_cmd = vidtv_send_diseqc_msg,
 405         .diseqc_send_burst      = vidtv_diseqc_send_burst,
 406
 407 };
 408
 409 static const struct i2c_device_id vidtv_demod_i2c_id_table[] = {
 410         {"dvb_vidtv_demod", 0},
 411         {}
 412 };
 413 MODULE_DEVICE_TABLE(i2c, vidtv_demod_i2c_id_table);
 414
 415 static int vidtv_demod_i2c_probe(struct i2c_client *client,
 416                                  const struct i2c_device_id *id)
 417 {
 418         struct vidtv_tuner_config *config = client->dev.platform_data;
 419         struct vidtv_demod_state *state;
 420
 421         /* allocate memory for the internal state */
 422         state = kzalloc(sizeof(*state), GFP_KERNEL);
 423         if (!state)
 424                 return -ENOMEM;
 425
 426         /* create dvb_frontend */
 427         memcpy(&state->frontend.ops,
 428                &vidtv_demod_ops,
 429                sizeof(struct dvb_frontend_ops));
 430
 431         memcpy(&state->config, config, sizeof(state->config));
 432
 433         state->frontend.demodulator_priv = state;
 434         i2c_set_clientdata(client, state);
 435
 436         vidtv_clean_stats(&state->frontend);
 437
 438         return 0;
 439 }
 440
 441 static int vidtv_demod_i2c_remove(struct i2c_client *client)
 442 {
 443         struct vidtv_demod_state *state = i2c_get_clientdata(client);
 444
 445         kfree(state);
 446
 447         return 0;
 448 }
 449
 450 static struct i2c_driver vidtv_demod_i2c_driver = {
 451         .driver = {
 452                 .name                = "dvb_vidtv_demod",
 453                 .suppress_bind_attrs = true,
 454         },
 455         .probe    = vidtv_demod_i2c_probe,
 456         .remove   = vidtv_demod_i2c_remove,
 457         .id_table = vidtv_demod_i2c_id_table,
 458 };
 459
 460 module_i2c_driver(vidtv_demod_i2c_driver);
 461
 462 MODULE_DESCRIPTION("Virtual DVB Demodulator Driver");
 463 MODULE_AUTHOR("Daniel W. S. Almeida");
 464 MODULE_LICENSE("GPL");