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.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
---
drivers/media/dvb-frontends/mb86a20s.c | 186 ++++++++++++++++++++++++++++-----
1 file changed, 162 insertions(+), 24 deletions(-)
diff --git a/drivers/media/dvb-frontends/mb86a20s.c b/drivers/media/dvb-frontends/mb86a20s.c
index 6265003..b612985 100644
--- a/drivers/media/dvb-frontends/mb86a20s.c
+++ b/drivers/media/dvb-frontends/mb86a20s.c
@@ -30,6 +30,8 @@ struct mb86a20s_state {
struct dvb_frontend frontend;
+ u32 estimated_rate[3];
+
bool need_init;
/*
@@ -89,31 +91,20 @@ static struct regdata mb86a20s_init[] = {
/*
* On this demod, when the bit count reaches the count below,
- * it collects the bit error count.
- *
- * As FE thread runs on every 3 seconds, adjust the counters to
- * provide one collect before 3 seconds, at the worse case (DQPSK,
- * 1/4 guard interval, 1/2 FEC, 1-seg rate is 280 Mbps, and
- * 3 seconds takes 0xcdb9f bits. Rounds it down to 0xccfff
- *
- * It should be noticed, however, that, with QAM-64 1/32 guard interval,
- * 1 segment bit rate is 1.78 Mbps, and 12-seg is about 21.5 Mbps.
- * At such rate, the time to measure BER is about 40 ms.
- *
- * It makes sense to change the logic there to use TMCC parameters and
- * adjust the counters in order to have all of them to take a little
- * less than 3 seconds, in order to have a more realistic BER rate,
- * instead of having short samples for 12-segs.
+ * 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
+ * will be adjusted later in the driver's code.
*/
{ 0x52, 0x01 }, /* Turn on BER before Viterbi */
- { 0x50, 0xa7 }, { 0x51, 0x0c },
- { 0x50, 0xa8 }, { 0x51, 0xcf },
+ { 0x50, 0xa7 }, { 0x51, 0x00 },
+ { 0x50, 0xa8 }, { 0x51, 0xff },
{ 0x50, 0xa9 }, { 0x51, 0xff },
- { 0x50, 0xaa }, { 0x51, 0x0c },
- { 0x50, 0xab }, { 0x51, 0xcf },
+ { 0x50, 0xaa }, { 0x51, 0x00 },
+ { 0x50, 0xab }, { 0x51, 0xff },
{ 0x50, 0xac }, { 0x51, 0xff },
- { 0x50, 0xad }, { 0x51, 0x0c },
- { 0x50, 0xae }, { 0x51, 0xcf },
+ { 0x50, 0xad }, { 0x51, 0x00 },
+ { 0x50, 0xae }, { 0x51, 0xff },
{ 0x50, 0xaf }, { 0x51, 0xff },
{ 0x5e, 0x07 },
@@ -208,7 +199,7 @@ static struct regdata mb86a20s_clear_stats[] = {
*/
static int mb86a20s_i2c_writereg(struct mb86a20s_state *state,
- u8 i2c_addr, int reg, int data)
+ u8 i2c_addr, u8 reg, u8 data)
{
u8 buf[] = { reg, data };
struct i2c_msg msg = {
@@ -504,6 +495,112 @@ 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;
+
+ /*
+ * default is always the lowest bit rate, to be sure that it will
+ * take less than 1 second to count the bits
+ */
+ 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;
+ }
+
+ /*
+ * Estimates a rate below the real one, to have more hope that the
+ * BER calculus will finish before 1 second.
+ */
+ rate = (isdbt_rate[m][f][i] >> 16) << 15;
+
+ /* Multiplies the rate by the number of segments */
+ rate *= segment;
+
+ 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;
@@ -533,10 +630,11 @@ 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;
@@ -558,6 +656,10 @@ 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);
@@ -754,6 +856,42 @@ static int mb86a20s_get_ber_before_vterbi(struct dvb_frontend *fe,
"%s: bit count before Viterbi for layer %c: %d.\n",
__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)
--
1.7.11.7
--
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