From d01a8ee37afdeb1a00458a79854a1672ada5c9f0 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Mon, 14 Jan 2013 20:34:55 -0300 Subject: [media] mb86a20s: improve bit error count for BER Do a better job on setting the bit error counters, in order to have all layer measures to happen in a little less than one second. Reviewed-by: Antti Palosaari Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb-frontends/mb86a20s.c | 160 ++++++++++++++++++++++++++++++++- 1 file changed, 157 insertions(+), 3 deletions(-) diff --git a/drivers/media/dvb-frontends/mb86a20s.c b/drivers/media/dvb-frontends/mb86a20s.c index 354ea664b713..c68e4676e5fd 100644 --- a/drivers/media/dvb-frontends/mb86a20s.c +++ b/drivers/media/dvb-frontends/mb86a20s.c @@ -31,6 +31,8 @@ struct mb86a20s_state { struct dvb_frontend frontend; + u32 estimated_rate[3]; + bool need_init; }; @@ -39,6 +41,8 @@ struct regdata { u8 data; }; +#define BER_SAMPLING_RATE 1 /* Seconds */ + /* * Initialization sequence: Use whatevere default values that PV SBTVD * does on its initialisation, obtained via USB snoop @@ -87,7 +91,7 @@ static struct regdata mb86a20s_init[] = { * it collects the bit error count. The bit counters are initialized * to 65535 here. This warrants that all of them will be quickly * calculated when device gets locked. As TMCC is parsed, the values - * can be adjusted later in the driver's code. + * will be adjusted later in the driver's code. */ { 0x52, 0x01 }, /* Turn on BER before Viterbi */ { 0x50, 0xa7 }, { 0x51, 0x00 }, @@ -485,6 +489,113 @@ static void mb86a20s_reset_frontend_cache(struct dvb_frontend *fe) c->isdbt_sb_segment_count = 0; } +/* + * Estimates the bit rate using the per-segment bit rate given by + * ABNT/NBR 15601 spec (table 4). + */ +static u32 isdbt_rate[3][5][4] = { + { /* DQPSK/QPSK */ + { 280850, 312060, 330420, 340430 }, /* 1/2 */ + { 374470, 416080, 440560, 453910 }, /* 2/3 */ + { 421280, 468090, 495630, 510650 }, /* 3/4 */ + { 468090, 520100, 550700, 567390 }, /* 5/6 */ + { 491500, 546110, 578230, 595760 }, /* 7/8 */ + }, { /* QAM16 */ + { 561710, 624130, 660840, 680870 }, /* 1/2 */ + { 748950, 832170, 881120, 907820 }, /* 2/3 */ + { 842570, 936190, 991260, 1021300 }, /* 3/4 */ + { 936190, 1040210, 1101400, 1134780 }, /* 5/6 */ + { 983000, 1092220, 1156470, 1191520 }, /* 7/8 */ + }, { /* QAM64 */ + { 842570, 936190, 991260, 1021300 }, /* 1/2 */ + { 1123430, 1248260, 1321680, 1361740 }, /* 2/3 */ + { 1263860, 1404290, 1486900, 1531950 }, /* 3/4 */ + { 1404290, 1560320, 1652110, 1702170 }, /* 5/6 */ + { 1474500, 1638340, 1734710, 1787280 }, /* 7/8 */ + } +}; + +static void mb86a20s_layer_bitrate(struct dvb_frontend *fe, u32 layer, + u32 modulation, u32 fec, u32 interleaving, + u32 segment) +{ + struct mb86a20s_state *state = fe->demodulator_priv; + u32 rate; + int m, f, i; + + /* + * If modulation/fec/interleaving is not detected, the default is + * to consider the lowest bit rate, to avoid taking too long time + * to get BER. + */ + switch (modulation) { + case DQPSK: + case QPSK: + default: + m = 0; + break; + case QAM_16: + m = 1; + break; + case QAM_64: + m = 2; + break; + } + + switch (fec) { + default: + case FEC_1_2: + case FEC_AUTO: + f = 0; + break; + case FEC_2_3: + f = 1; + break; + case FEC_3_4: + f = 2; + break; + case FEC_5_6: + f = 3; + break; + case FEC_7_8: + f = 4; + break; + } + + switch (interleaving) { + default: + case GUARD_INTERVAL_1_4: + i = 0; + break; + case GUARD_INTERVAL_1_8: + i = 1; + break; + case GUARD_INTERVAL_1_16: + i = 2; + break; + case GUARD_INTERVAL_1_32: + i = 3; + break; + } + + /* Samples BER at BER_SAMPLING_RATE seconds */ + rate = isdbt_rate[m][f][i] * segment * BER_SAMPLING_RATE; + + /* Avoids sampling too quickly or to overflow the register */ + if (rate < 256) + rate = 256; + else if (rate > (1 << 24) - 1) + rate = (1 << 24) - 1; + + dev_dbg(&state->i2c->dev, + "%s: layer %c bitrate: %d kbps; counter = %d (0x%06x)\n", + __func__, 'A' + layer, segment * isdbt_rate[m][f][i]/1000, + rate, rate); + + state->estimated_rate[i] = rate; +} + + static int mb86a20s_get_frontend(struct dvb_frontend *fe) { struct mb86a20s_state *state = fe->demodulator_priv; @@ -514,10 +625,11 @@ static int mb86a20s_get_frontend(struct dvb_frontend *fe) rc = mb86a20s_get_segment_count(state, i); if (rc < 0) goto noperlayer_error; - if (rc >= 0 && rc < 14) + if (rc >= 0 && rc < 14) { c->layer[i].segment_count = rc; - else { + } else { c->layer[i].segment_count = 0; + state->estimated_rate[i] = 0; continue; } c->isdbt_layer_enabled |= 1 << i; @@ -539,6 +651,10 @@ static int mb86a20s_get_frontend(struct dvb_frontend *fe) dev_dbg(&state->i2c->dev, "%s: interleaving %d.\n", __func__, rc); c->layer[i].interleaving = rc; + mb86a20s_layer_bitrate(fe, i, c->layer[i].modulation, + c->layer[i].fec, + c->layer[i].interleaving, + c->layer[i].segment_count); } rc = mb86a20s_writereg(state, 0x6d, 0x84); @@ -730,6 +846,42 @@ static int mb86a20s_get_ber_before_vterbi(struct dvb_frontend *fe, __func__, 'A' + layer, *count); + /* + * As we get TMCC data from the frontend, we can better estimate the + * BER bit counters, in order to do the BER measure during a longer + * time. Use those data, if available, to update the bit count + * measure. + */ + + if (state->estimated_rate[layer] + && state->estimated_rate[layer] != *count) { + dev_dbg(&state->i2c->dev, + "%s: updating layer %c counter to %d.\n", + __func__, 'A' + layer, state->estimated_rate[layer]); + rc = mb86a20s_writereg(state, 0x50, 0xa7 + layer * 3); + if (rc < 0) + return rc; + rc = mb86a20s_writereg(state, 0x51, + state->estimated_rate[layer] >> 16); + if (rc < 0) + return rc; + rc = mb86a20s_writereg(state, 0x50, 0xa8 + layer * 3); + if (rc < 0) + return rc; + rc = mb86a20s_writereg(state, 0x51, + state->estimated_rate[layer] >> 8); + if (rc < 0) + return rc; + rc = mb86a20s_writereg(state, 0x50, 0xa9 + layer * 3); + if (rc < 0) + return rc; + rc = mb86a20s_writereg(state, 0x51, + state->estimated_rate[layer]); + if (rc < 0) + return rc; + } + + /* Reset counter to collect new data */ rc = mb86a20s_writereg(state, 0x53, 0x07 & ~(1 << layer)); if (rc < 0) @@ -922,8 +1074,10 @@ static int mb86a20s_set_frontend(struct dvb_frontend *fe) if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 0); + rc = mb86a20s_writeregdata(state, mb86a20s_reset_reception); mb86a20s_reset_counters(fe); + if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 1); -- cgit v1.2.3