1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * The Virtual DTV 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 #ifndef VIDTV_DEMOD_H
12 #define VIDTV_DEMOD_H
13 
14 #include <linux/dvb/frontend.h>
15 #include <media/dvb_frontend.h>
16 
17 /**
18  * struct vidtv_demod_cnr_to_qual_s - Map CNR values to a given combination of
19  * modulation and fec_inner
20  * @modulation: see enum fe_modulation
21  * @fec: see enum fe_fec_rate
22  *
23  * This struct matches values for 'good' and 'ok' CNRs given the combination
24  * of modulation and fec_inner in use. We might simulate some noise if the
25  * signal quality is not too good.
26  *
27  * The values were taken from libdvbv5.
28  */
29 struct vidtv_demod_cnr_to_qual_s {
30 	u32 modulation;
31 	u32 fec;
32 	u32 cnr_ok;
33 	u32 cnr_good;
34 };
35 
36 /**
37  * struct vidtv_demod_config - Configuration used to init the demod
38  * @drop_tslock_prob_on_low_snr: probability of losing the lock due to low snr
39  * @recover_tslock_prob_on_good_snr: probability of recovering when the signal
40  * improves
41  *
42  * The configuration used to init the demodulator module, usually filled
43  * by a bridge driver. For vidtv, this is filled by vidtv_bridge before the
44  * demodulator module is probed.
45  */
46 struct vidtv_demod_config {
47 	u8 drop_tslock_prob_on_low_snr;
48 	u8 recover_tslock_prob_on_good_snr;
49 };
50 
51 /**
52  * struct vidtv_demod_state - The demodulator state
53  * @frontend: The frontend structure allocated by the demod.
54  * @config: The config used to init the demod.
55  * @poll_snr: The task responsible for periodically checking the simulated
56  * signal quality, eventually dropping or reacquiring the TS lock.
57  * @status: the demod status.
58  * @cold_start: Whether the demod has not been init yet.
59  * @poll_snr_thread_running: Whether the task responsible for periodically
60  * checking the simulated signal quality is running.
61  * @poll_snr_thread_restart: Whether we should restart the poll_snr task.
62  */
63 struct vidtv_demod_state {
64 	struct dvb_frontend frontend;
65 	struct vidtv_demod_config config;
66 	enum fe_status status;
67 	u16 tuner_cnr;
68 };
69 #endif // VIDTV_DEMOD_H
70