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 -= get_random_u32_below(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 -= get_random_u32_below(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 (get_random_u32_below(100) < config->drop_tslock_prob_on_low_snr) 217 state->status = 0; 218 } else { 219 /* recover if the signal improves */ 220 if (get_random_u32_below(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" }, 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 { 417 struct vidtv_tuner_config *config = client->dev.platform_data; 418 struct vidtv_demod_state *state; 419 420 /* allocate memory for the internal state */ 421 state = kzalloc(sizeof(*state), GFP_KERNEL); 422 if (!state) 423 return -ENOMEM; 424 425 /* create dvb_frontend */ 426 memcpy(&state->frontend.ops, 427 &vidtv_demod_ops, 428 sizeof(struct dvb_frontend_ops)); 429 430 memcpy(&state->config, config, sizeof(state->config)); 431 432 state->frontend.demodulator_priv = state; 433 i2c_set_clientdata(client, state); 434 435 vidtv_clean_stats(&state->frontend); 436 437 return 0; 438 } 439 440 static void vidtv_demod_i2c_remove(struct i2c_client *client) 441 { 442 struct vidtv_demod_state *state = i2c_get_clientdata(client); 443 444 kfree(state); 445 } 446 447 static struct i2c_driver vidtv_demod_i2c_driver = { 448 .driver = { 449 .name = "dvb_vidtv_demod", 450 .suppress_bind_attrs = true, 451 }, 452 .probe = vidtv_demod_i2c_probe, 453 .remove = vidtv_demod_i2c_remove, 454 .id_table = vidtv_demod_i2c_id_table, 455 }; 456 457 module_i2c_driver(vidtv_demod_i2c_driver); 458 459 MODULE_DESCRIPTION("Virtual DVB Demodulator Driver"); 460 MODULE_AUTHOR("Daniel W. S. Almeida"); 461 MODULE_LICENSE("GPL"); 462