[media] mb86a20s: add BER measurement

Add the methods to read bit error/bit count measurements from
mb86a20s. On ISDB-T devices, those reads are done per layer.
However, as userspace applications may not be aware of that,
add a global measure that will sum the bit errors and bit
counts for each layer, storing them into a global value.

Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/dvb-frontends/mb86a20s.c b/drivers/media/dvb-frontends/mb86a20s.c
index d7668e6..354ea66 100644 (file)
--- a/drivers/media/dvb-frontends/mb86a20s.c
+++ b/drivers/media/dvb-frontends/mb86a20s.c
@@ -650,10 +650,95 @@ static int mb86a20s_reset_counters(struct dvb_frontend *fe)
        if (rc < 0)
                goto err;
 
+       goto ok;
 err:
+       dev_err(&state->i2c->dev,
+               "%s: Can't reset FE statistics (error %d).\n",
+               __func__, rc);
+ok:
        return rc;
 }
 
+static int mb86a20s_get_ber_before_vterbi(struct dvb_frontend *fe,
+                                         unsigned layer,
+                                         u32 *error, u32 *count)
+{
+       struct mb86a20s_state *state = fe->demodulator_priv;
+       int rc;
+
+       dev_dbg(&state->i2c->dev, "%s called.\n", __func__);
+
+       if (layer >= 3)
+               return -EINVAL;
+
+       /* Check if the BER measures are already available */
+       rc = mb86a20s_readreg(state, 0x54);
+       if (rc < 0)
+               return rc;
+
+       /* Check if data is available for that layer */
+       if (!(rc & (1 << layer))) {
+               dev_dbg(&state->i2c->dev,
+                       "%s: BER for layer %c is not available yet.\n",
+                       __func__, 'A' + layer);
+               return -EBUSY;
+       }
+
+       /* Read Bit Error Count */
+       rc = mb86a20s_readreg(state, 0x55 + layer * 3);
+       if (rc < 0)
+               return rc;
+       *error = rc << 16;
+       rc = mb86a20s_readreg(state, 0x56 + layer * 3);
+       if (rc < 0)
+               return rc;
+       *error |= rc << 8;
+       rc = mb86a20s_readreg(state, 0x57 + layer * 3);
+       if (rc < 0)
+               return rc;
+       *error |= rc;
+
+       dev_dbg(&state->i2c->dev,
+               "%s: bit error before Viterbi for layer %c: %d.\n",
+               __func__, 'A' + layer, *error);
+
+       /* Read Bit Count */
+       rc = mb86a20s_writereg(state, 0x50, 0xa7 + layer * 3);
+       if (rc < 0)
+               return rc;
+       rc = mb86a20s_readreg(state, 0x51);
+       if (rc < 0)
+               return rc;
+       *count = rc << 16;
+       rc = mb86a20s_writereg(state, 0x50, 0xa8 + layer * 3);
+       if (rc < 0)
+               return rc;
+       rc = mb86a20s_readreg(state, 0x51);
+       if (rc < 0)
+               return rc;
+       *count |= rc << 8;
+       rc = mb86a20s_writereg(state, 0x50, 0xa9 + layer * 3);
+       if (rc < 0)
+               return rc;
+       rc = mb86a20s_readreg(state, 0x51);
+       if (rc < 0)
+               return rc;
+       *count |= rc;
+
+       dev_dbg(&state->i2c->dev,
+               "%s: bit count before Viterbi for layer %c: %d.\n",
+               __func__, 'A' + layer, *count);
+
+
+       /* Reset counter to collect new data */
+       rc = mb86a20s_writereg(state, 0x53, 0x07 & ~(1 << layer));
+       if (rc < 0)
+               return rc;
+       rc = mb86a20s_writereg(state, 0x53, 0x07);
+
+       return 0;
+}
+
 static void mb86a20s_stats_not_ready(struct dvb_frontend *fe)
 {
        struct mb86a20s_state *state = fe->demodulator_priv;
@@ -688,6 +773,72 @@ static void mb86a20s_stats_not_ready(struct dvb_frontend *fe)
        }
 }
 
+static int mb86a20s_get_stats(struct dvb_frontend *fe)
+{
+       struct mb86a20s_state *state = fe->demodulator_priv;
+       struct dtv_frontend_properties *c = &fe->dtv_property_cache;
+       int rc = 0, i;
+       u32 bit_error = 0, bit_count = 0;
+       u32 t_pre_bit_error = 0, t_pre_bit_count = 0;
+       int active_layers = 0, ber_layers = 0;
+
+       /* Get per-layer stats */
+       for (i = 0; i < 3; i++) {
+               if (c->isdbt_layer_enabled & (1 << i)) {
+                       /* Layer is active and has rc segments */
+                       active_layers++;
+
+                       /* Read per-layer BER */
+                       /* Handle BER before vterbi */
+                       rc = mb86a20s_get_ber_before_vterbi(fe, i,
+                                                       &bit_error,
+                                                       &bit_count);
+                       if (rc >= 0) {
+                               c->pre_bit_error.stat[1 + i].scale = FE_SCALE_COUNTER;
+                               c->pre_bit_error.stat[1 + i].uvalue += bit_error;
+                               c->pre_bit_count.stat[1 + i].scale = FE_SCALE_COUNTER;
+                               c->pre_bit_count.stat[1 + i].uvalue += bit_count;
+                       } else if (rc != -EBUSY) {
+                               /*
+                                       * If an I/O error happened,
+                                       * measures are now unavailable
+                                       */
+                               c->pre_bit_error.stat[1 + i].scale = FE_SCALE_NOT_AVAILABLE;
+                               c->pre_bit_count.stat[1 + i].scale = FE_SCALE_NOT_AVAILABLE;
+                               dev_err(&state->i2c->dev,
+                                       "%s: Can't get BER for layer %c (error %d).\n",
+                                       __func__, 'A' + i, rc);
+                       }
+
+                       if (c->block_error.stat[1 + i].scale != FE_SCALE_NOT_AVAILABLE)
+                               ber_layers++;
+
+                       /* Update total BER */
+                       t_pre_bit_error += c->pre_bit_error.stat[1 + i].uvalue;
+                       t_pre_bit_count += c->pre_bit_count.stat[1 + i].uvalue;
+               }
+       }
+
+       /*
+        * Start showing global count if at least one error count is
+        * available.
+        */
+       if (ber_layers) {
+               /*
+                * At least one per-layer BER measure was read. We can now
+                * calculate the total BER
+                *
+                * Total Bit Error/Count is calculated as the sum of the
+                * bit errors on all active layers.
+                */
+               c->pre_bit_error.stat[0].scale = FE_SCALE_COUNTER;
+               c->pre_bit_error.stat[0].uvalue = t_pre_bit_error;
+               c->pre_bit_count.stat[0].scale = FE_SCALE_COUNTER;
+               c->pre_bit_count.stat[0].uvalue = t_pre_bit_count;
+       }
+
+       return rc;
+}
 
 /*
  * The functions below are called via DVB callbacks, so they need to
@@ -797,14 +948,21 @@ static int mb86a20s_read_status_and_stats(struct dvb_frontend *fe,
                mb86a20s_stats_not_ready(fe);
                mb86a20s_reset_frontend_cache(fe);
        }
-       if (rc < 0)
+       if (rc < 0) {
+               dev_err(&state->i2c->dev,
+                       "%s: Can't read frontend lock status\n", __func__);
                goto error;
+       }
 
        /* Get signal strength */
        rc = mb86a20s_read_signal_strength(fe);
        if (rc < 0) {
+               dev_err(&state->i2c->dev,
+                       "%s: Can't reset VBER registers.\n", __func__);
                mb86a20s_stats_not_ready(fe);
                mb86a20s_reset_frontend_cache(fe);
+
+               rc = 0;         /* Status is OK */
                goto error;
        }
        /* Fill signal strength */
@@ -813,15 +971,32 @@ static int mb86a20s_read_status_and_stats(struct dvb_frontend *fe,
        if (*status & FE_HAS_LOCK) {
                /* Get TMCC info*/
                rc = mb86a20s_get_frontend(fe);
-               if (rc < 0)
+               if (rc < 0) {
+                       dev_err(&state->i2c->dev,
+                               "%s: Can't get FE TMCC data.\n", __func__);
+                       rc = 0;         /* Status is OK */
+                       goto error;
+               }
+
+               /* Get statistics */
+               rc = mb86a20s_get_stats(fe);
+               if (rc < 0 && rc != -EBUSY) {
+                       dev_err(&state->i2c->dev,
+                               "%s: Can't get FE statistics.\n", __func__);
+                       rc = 0;
                        goto error;
+               }
+               rc = 0; /* Don't return EBUSY to userspace */
        }
+       goto ok;
 
+error:
        mb86a20s_stats_not_ready(fe);
 
+ok:
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);
-error:
+
        return rc;
 }