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
vidtv_match_cnr_s(struct dvb_frontend * fe)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
vidtv_clean_stats(struct dvb_frontend * fe)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
vidtv_demod_update_stats(struct dvb_frontend * fe)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
vidtv_demod_read_status(struct dvb_frontend * fe,enum fe_status * status)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
vidtv_demod_read_signal_strength(struct dvb_frontend * fe,u16 * strength)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 */
vidtv_demod_get_frontend(struct dvb_frontend * fe,struct dtv_frontend_properties * p)256 static int vidtv_demod_get_frontend(struct dvb_frontend *fe,
257 struct dtv_frontend_properties *p)
258 {
259 return 0;
260 }
261
vidtv_demod_set_frontend(struct dvb_frontend * fe)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 */
vidtv_demod_set_tone(struct dvb_frontend * fe,enum fe_sec_tone_mode tone)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 */
vidtv_demod_set_voltage(struct dvb_frontend * fe,enum fe_sec_voltage voltage)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 */
vidtv_send_diseqc_msg(struct dvb_frontend * fe,struct dvb_diseqc_master_cmd * cmd)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 */
vidtv_diseqc_send_burst(struct dvb_frontend * fe,enum fe_sec_mini_cmd burst)340 static int vidtv_diseqc_send_burst(struct dvb_frontend *fe,
341 enum fe_sec_mini_cmd burst)
342 {
343 return 0;
344 }
345
vidtv_demod_release(struct dvb_frontend * fe)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
vidtv_demod_i2c_probe(struct i2c_client * client)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
vidtv_demod_i2c_remove(struct i2c_client * client)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
