// SPDX-License-Identifier: GPL-2.0-or-later
/*
* The Virtual DVB test driver serves as a reference DVB driver and helps
* validate the existing APIs in the media subsystem. It can also aid
* developers working on userspace applications.
*
* Copyright (C) 2020 Daniel W. S. Almeida
* Based on the example driver written by Emard <emard@softhome.net>
*/
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/ratelimit.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/workqueue.h>
#include <media/dvb_frontend.h>
#include "vidtv_demod.h"
#define POLL_THRD_TIME 2000 /* ms */
static const struct vidtv_demod_cnr_to_qual_s vidtv_demod_c_cnr_2_qual[] = {
/* from libdvbv5 source code, in milli db */
{ QAM_256, FEC_NONE, 34000, 38000},
{ QAM_64, FEC_NONE, 30000, 34000},
};
static const struct vidtv_demod_cnr_to_qual_s vidtv_demod_s_cnr_2_qual[] = {
/* from libdvbv5 source code, in milli db */
{ QPSK, FEC_1_2, 7000, 10000},
{ QPSK, FEC_2_3, 9000, 12000},
{ QPSK, FEC_3_4, 10000, 13000},
{ QPSK, FEC_5_6, 11000, 14000},
{ QPSK, FEC_7_8, 12000, 15000},
};
static const struct vidtv_demod_cnr_to_qual_s vidtv_demod_s2_cnr_2_qual[] = {
/* from libdvbv5 source code, in milli db */
{ QPSK, FEC_1_2, 9000, 12000},
{ QPSK, FEC_2_3, 11000, 14000},
{ QPSK, FEC_3_4, 12000, 15000},
{ QPSK, FEC_5_6, 12000, 15000},
{ QPSK, FEC_8_9, 13000, 16000},
{ QPSK, FEC_9_10, 13500, 16500},
{ PSK_8, FEC_2_3, 14500, 17500},
{ PSK_8, FEC_3_4, 16000, 19000},
{ PSK_8, FEC_5_6, 17500, 20500},
{ PSK_8, FEC_8_9, 19000, 22000},
};
static const struct vidtv_demod_cnr_to_qual_s vidtv_demod_t_cnr_2_qual[] = {
/* from libdvbv5 source code, in milli db*/
{ QPSK, FEC_1_2, 4100, 5900},
{ QPSK, FEC_2_3, 6100, 9600},
{ QPSK, FEC_3_4, 7200, 12400},
{ QPSK, FEC_5_6, 8500, 15600},
{ QPSK, FEC_7_8, 9200, 17500},
{ QAM_16, FEC_1_2, 9800, 11800},
{ QAM_16, FEC_2_3, 12100, 15300},
{ QAM_16, FEC_3_4, 13400, 18100},
{ QAM_16, FEC_5_6, 14800, 21300},
{ QAM_16, FEC_7_8, 15700, 23600},
{ QAM_64, FEC_1_2, 14000, 16000},
{ QAM_64, FEC_2_3, 19900, 25400},
{ QAM_64, FEC_3_4, 24900, 27900},
{ QAM_64, FEC_5_6, 21300, 23300},
{ QAM_64, FEC_7_8, 22000, 24000},
};
static const struct vidtv_demod_cnr_to_qual_s *vidtv_match_cnr_s(struct dvb_frontend *fe)
{
const struct vidtv_demod_cnr_to_qual_s *cnr2qual = NULL;
struct device *dev = fe->dvb->device;
struct dtv_frontend_properties *c;
u32 array_size = 0;
u32 i;
c = &fe->dtv_property_cache;
switch (c->delivery_system) {
case SYS_DVBT:
case SYS_DVBT2:
cnr2qual = vidtv_demod_t_cnr_2_qual;
array_size = ARRAY_SIZE(vidtv_demod_t_cnr_2_qual);
break;
case SYS_DVBS:
cnr2qual = vidtv_demod_s_cnr_2_qual;
array_size = ARRAY_SIZE(vidtv_demod_s_cnr_2_qual);
break;
case SYS_DVBS2:
cnr2qual = vidtv_demod_s2_cnr_2_qual;
array_size = ARRAY_SIZE(vidtv_demod_s2_cnr_2_qual);
break;
case SYS_DVBC_ANNEX_A:
cnr2qual = vidtv_demod_c_cnr_2_qual;
array_size = ARRAY_SIZE(vidtv_demod_c_cnr_2_qual);
break;
default:
dev_warn_ratelimited(dev,
"%s: unsupported delivery system: %u\n",
__func__,
c->delivery_system);
break;
}
for (i = 0; i < array_size; i++)
if (cnr2qual[i].modulation == c->modulation &&
cnr2qual[i].fec == c->fec_inner)
return &cnr2qual[i];
return NULL; /* not found */
}
static void vidtv_clean_stats(struct dvb_frontend *fe)
{
struct dtv_frontend_properties *c = &fe->dtv_property_cache;
/* Fill the length of each status counter */
/* Signal is always available */
c->strength.len = 1;
c->strength.stat[0].scale = FE_SCALE_DECIBEL;
c->strength.stat[0].svalue = 0;
/* Usually available only after Viterbi lock */
c->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
c->cnr.stat[0].svalue = 0;
c->cnr.len = 1;
/* Those depends on full lock */
c->pre_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
c->pre_bit_error.stat[0].uvalue = 0;
c->pre_bit_error.len = 1;
c->pre_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
c->pre_bit_count.stat[0].uvalue = 0;
c->pre_bit_count.len = 1;
c->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
c->post_bit_error.stat[0].uvalue = 0;
c->post_bit_error.len = 1;
c->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
c->post_bit_count.stat[0].uvalue = 0;
c->post_bit_count.len = 1;
c->block_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
c->block_error.stat[0].uvalue = 0;
c->block_error.len = 1;
c->block_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
c->block_count.stat[0].uvalue = 0;
c->block_count.len = 1;
}
static void vidtv_demod_update_stats(struct dvb_frontend *fe)
{
struct dtv_frontend_properties *c = &fe->dtv_property_cache;
struct vidtv_demod_state *state = fe->demodulator_priv;
u32 scale;
if (state->status & FE_HAS_LOCK) {
scale = FE_SCALE_COUNTER;
c->cnr.stat[0].scale = FE_SCALE_DECIBEL;
} else {
scale = FE_SCALE_NOT_AVAILABLE;
c->cnr.stat[0].scale = scale;
}
c->pre_bit_error.stat[0].scale = scale;
c->pre_bit_count.stat[0].scale = scale;
c->post_bit_error.stat[0].scale = scale;
c->post_bit_count.stat[0].scale = scale;
c->block_error.stat[0].scale = scale;
c->block_count.stat[0].scale = scale;
/*
* Add a 0.5% of randomness at the signal strength and CNR,
* and make them different, as we want to have something closer
* to a real case scenario.
*
* Also, usually, signal strength is a negative number in dBm.
*/
c->strength.stat[0].svalue = state->tuner_cnr;
c->strength.stat[0].svalue -= prandom_u32_max(state->tuner_cnr / 50);
c->strength.stat[0].svalue -= 68000; /* Adjust to a better range */
c->cnr.stat[0].svalue = state->tuner_cnr;
c->cnr.stat[0].svalue -= prandom_u32_max(state->tuner_cnr / 50);
}
static int vidtv_demod_read_status(struct dvb_frontend *fe,
enum fe_status *status)
{
struct vidtv_demod_state *state = fe->demodulator_priv;
const struct vidtv_demod_cnr_to_qual_s *cnr2qual = NULL;
struct vidtv_demod_config *config = &state->config;
u16 snr = 0;
/* Simulate random lost of signal due to a bad-tuned channel */
cnr2qual = vidtv_match_cnr_s(&state->frontend);
if (cnr2qual && state->tuner_cnr < cnr2qual->cnr_good &&
state->frontend.ops.tuner_ops.get_rf_strength) {
state->frontend.ops.tuner_ops.get_rf_strength(&state->frontend,
&snr);
if (snr < cnr2qual->cnr_ok) {
/* eventually lose the TS lock */
if (prandom_u32_max(100) < config->drop_tslock_prob_on_low_snr)
state->status = 0;
} else {
/* recover if the signal improves */
if (prandom_u32_max(100) <
config->recover_tslock_prob_on_good_snr)
state->status = FE_HAS_SIGNAL |
FE_HAS_CARRIER |
FE_HAS_VITERBI |
FE_HAS_SYNC |
FE_HAS_LOCK;
}
}
vidtv_demod_update_stats(&state->frontend);
*status = state->status;
return 0;
}
static int vidtv_demod_read_signal_strength(struct dvb_frontend *fe,
u16 *strength)
{
struct dtv_frontend_properties *c = &fe->dtv_property_cache;
*strength = c->strength.stat[0].uvalue;
return 0;
}
/*
* NOTE:
* This is implemented here just to be used as an example for real
* demod drivers.
*
* Should only be implemented if it actually reads something from the hardware.
* Also, it should check for the locks, in order to avoid report wrong data
* to userspace.
*/
static int vidtv_demod_get_frontend(struct dvb_frontend *fe,
struct dtv_frontend_properties *p)
{
return 0;
}
static int vidtv_demod_set_frontend(struct dvb_frontend *fe)
{
struct vidtv_demod_state *state = fe->demodulator_priv;
u32 tuner_status = 0;
int ret;
if (!fe->ops.tuner_ops.set_params)
return 0;
fe->ops.tuner_ops.set_params(fe);
/* store the CNR returned by the tuner */
ret = fe->ops.tuner_ops.get_rf_strength(fe, &state->tuner_cnr);
if (ret < 0)
return ret;
fe->ops.tuner_ops.get_status(fe, &tuner_status);
state->status = (state->tuner_cnr > 0) ? FE_HAS_SIGNAL |
FE_HAS_CARRIER |
FE_HAS_VITERBI |
FE_HAS_SYNC |
FE_HAS_LOCK :
0;
vidtv_demod_update_stats(fe);
if (fe->ops.i2c_gate_ctrl)
fe->ops.i2c_gate_ctrl(fe, 0);
return 0;
}
/*
* NOTE:
* This is implemented here just to be used as an example for real
* demod drivers.
*
* Should only be implemented if the demod has support for DVB-S or DVB-S2
*/
static int vidtv_demod_set_tone(struct dvb_frontend *fe,
enum fe_sec_tone_mode tone)
{
return 0;
}
/*
* NOTE:
* This is implemented here just to be used as an example for real
* demod drivers.
*
* Should only be implemented if the demod has support for DVB-S or DVB-S2
*/
static int vidtv_demod_set_voltage(struct dvb_frontend *fe,
enum fe_sec_voltage voltage)
{
return 0;
}
/*
* NOTE:
* This is implemented here just to be used as an example for real
* demod drivers.
*
* Should only be implemented if the demod has support for DVB-S or DVB-S2
*/
static int vidtv_send_diseqc_msg(struct dvb_frontend *fe,
struct dvb_diseqc_master_cmd *cmd)
{
return 0;
}
/*
* NOTE:
* This is implemented here just to be used as an example for real
* demod drivers.
*
* Should only be implemented if the demod has support for DVB-S or DVB-S2
*/
static int vidtv_diseqc_send_burst(struct dvb_frontend *fe,
enum fe_sec_mini_cmd burst)
{
return 0;
}
static void vidtv_demod_release(struct dvb_frontend *fe)
{
struct vidtv_demod_state *state = fe->demodulator_priv;
kfree(state);
}
static const struct dvb_frontend_ops vidtv_demod_ops = {
.delsys = {
SYS_DVBT,
SYS_DVBT2,
SYS_DVBC_ANNEX_A,
SYS_DVBS,
SYS_DVBS2,
},
.info = {
.name = "Dummy demod for DVB-T/T2/C/S/S2",
.frequency_min_hz = 51 * MHz,
.frequency_max_hz = 2150 * MHz,
.frequency_stepsize_hz = 62500,
.frequency_tolerance_hz = 29500 * kHz,
.symbol_rate_min = 1000000,
.symbol_rate_max = 45000000,
.caps = FE_CAN_FEC_1_2 |
FE_CAN_FEC_2_3 |
FE_CAN_FEC_3_4 |
FE_CAN_FEC_4_5 |
FE_CAN_FEC_5_6 |
FE_CAN_FEC_6_7 |
FE_CAN_FEC_7_8 |
FE_CAN_FEC_8_9 |
FE_CAN_QAM_16 |
FE_CAN_QAM_64 |
FE_CAN_QAM_32 |
FE_CAN_QAM_128 |
FE_CAN_QAM_256 |
FE_CAN_QAM_AUTO |
FE_CAN_QPSK |
FE_CAN_FEC_AUTO |
FE_CAN_INVERSION_AUTO |
FE_CAN_TRANSMISSION_MODE_AUTO |
FE_CAN_GUARD_INTERVAL_AUTO |
FE_CAN_HIERARCHY_AUTO,
},
.release = vidtv_demod_release,
.set_frontend = vidtv_demod_set_frontend,
.get_frontend = vidtv_demod_get_frontend,
.read_status = vidtv_demod_read_status,
.read_signal_strength = vidtv_demod_read_signal_strength,
/* For DVB-S/S2 */
.set_voltage = vidtv_demod_set_voltage,
.set_tone = vidtv_demod_set_tone,
.diseqc_send_master_cmd = vidtv_send_diseqc_msg,
.diseqc_send_burst = vidtv_diseqc_send_burst,
};
static const struct i2c_device_id vidtv_demod_i2c_id_table[] = {
{"dvb_vidtv_demod", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, vidtv_demod_i2c_id_table);
static int vidtv_demod_i2c_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct vidtv_tuner_config *config = client->dev.platform_data;
struct vidtv_demod_state *state;
/* allocate memory for the internal state */
state = kzalloc(sizeof(*state), GFP_KERNEL);
if (!state)
return -ENOMEM;
/* create dvb_frontend */
memcpy(&state->frontend.ops,
&vidtv_demod_ops,
sizeof(struct dvb_frontend_ops));
memcpy(&state->config, config, sizeof(state->config));
state->frontend.demodulator_priv = state;
i2c_set_clientdata(client, state);
vidtv_clean_stats(&state->frontend);
return 0;
}
static int vidtv_demod_i2c_remove(struct i2c_client *client)
{
struct vidtv_demod_state *state = i2c_get_clientdata(client);
kfree(state);
return 0;
}
static struct i2c_driver vidtv_demod_i2c_driver = {
.driver = {
.name = "dvb_vidtv_demod",
.suppress_bind_attrs = true,
},
.probe = vidtv_demod_i2c_probe,
.remove = vidtv_demod_i2c_remove,
.id_table = vidtv_demod_i2c_id_table,
};
module_i2c_driver(vidtv_demod_i2c_driver);
MODULE_DESCRIPTION("Virtual DVB Demodulator Driver");
MODULE_AUTHOR("Daniel W. S. Almeida");
MODULE_LICENSE("GPL");