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