[media] cxd2841er: fix BER report via DVBv5 stats API

What userspace expects is to receive both bit_error and bit_count
counters. So, instead of doing the division at the Kernel,
return the counters for userspace to handle it the way it
wants.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 66 insertions, 71 deletions

diff --git a/drivers/media/dvb-frontends/cxd2841er.c b/drivers/media/dvb-frontends/cxd2841er.c
index 721fb074da7c..94de6ba3d0e2 100644
--- a/drivers/media/dvb-frontends/cxd2841er.c
+++ b/drivers/media/dvb-frontends/cxd2841er.c
@@ -1330,11 +1330,10 @@ static int cxd2841er_read_packet_errors_i(
         return 0;
 }
 
-static int cxd2841er_mon_read_ber_s(struct cxd2841er_priv *priv, u32 *ber)
+static int cxd2841er_mon_read_ber_s(struct cxd2841er_priv *priv,
+                                    u32 *bit_error, u32 *bit_count)
 {
         u8 data[11];
-        u32 bit_error, bit_count;
-        u32 temp_q, temp_r;
 
         /* Set SLV-T Bank : 0xA0 */
         cxd2841er_write_reg(priv, I2C_SLVT, 0x00, 0xa0);
@@ -1350,28 +1349,18 @@ static int cxd2841er_mon_read_ber_s(struct cxd2841er_priv *priv, u32 *ber)
          */
         cxd2841er_read_regs(priv, I2C_SLVT, 0x35, data, 11);
         if (data[0] & 0x01) {
-                bit_error = ((u32)(data[1]  & 0x3F) << 16) |
-                        ((u32)(data[2]  & 0xFF) <<  8) |
-                        (u32)(data[3]  & 0xFF);
-                bit_count = ((u32)(data[8]  & 0x3F) << 16) |
-                        ((u32)(data[9]  & 0xFF) <<  8) |
-                        (u32)(data[10] & 0xFF);
-                /*
-                 *      BER = bitError / bitCount
-                 *      = (bitError * 10^7) / bitCount
-                 *      = ((bitError * 625 * 125 * 128) / bitCount
-                 */
-                if ((bit_count == 0) || (bit_error > bit_count)) {
+                *bit_error = ((u32)(data[1]  & 0x3F) << 16) |
+                             ((u32)(data[2]  & 0xFF) <<  8) |
+                             (u32)(data[3]  & 0xFF);
+                *bit_count = ((u32)(data[8]  & 0x3F) << 16) |
+                             ((u32)(data[9]  & 0xFF) <<  8) |
+                             (u32)(data[10] & 0xFF);
+                if ((*bit_count == 0) || (*bit_error > *bit_count)) {
                         dev_dbg(&priv->i2c->dev,
                                 "%s(): invalid bit_error %d, bit_count %d\n",
-                                __func__, bit_error, bit_count);
+                                __func__, *bit_error, *bit_count);
                         return -EINVAL;
                 }
-                temp_q = div_u64_rem(10000000ULL * bit_error,
-                                                bit_count, &temp_r);
-                if (bit_count != 1 && temp_r >= bit_count / 2)
-                        temp_q++;
-                *ber = temp_q;
                 return 0;
         }
         dev_dbg(&priv->i2c->dev, "%s(): no data available\n", __func__);
@@ -1379,11 +1368,11 @@ static int cxd2841er_mon_read_ber_s(struct cxd2841er_priv *priv, u32 *ber)
 }
 
 
-static int cxd2841er_mon_read_ber_s2(struct cxd2841er_priv *priv, u32 *ber)
+static int cxd2841er_mon_read_ber_s2(struct cxd2841er_priv *priv,
+                                     u32 *bit_error, u32 *bit_count)
 {
         u8 data[5];
-        u32 bit_error, period;
-        u32 temp_q, temp_r;
+        u32 period;
 
         /* Set SLV-T Bank : 0xB2 */
         cxd2841er_write_reg(priv, I2C_SLVT, 0x00, 0xb2);
@@ -1398,10 +1387,10 @@ static int cxd2841er_mon_read_ber_s2(struct cxd2841er_priv *priv, u32 *ber)
         cxd2841er_read_regs(priv, I2C_SLVT, 0x30, data, 5);
         if (data[0] & 0x01) {
                 /* Bit error count */
-                bit_error = ((u32)(data[1] & 0x0F) << 24) |
-                        ((u32)(data[2] & 0xFF) << 16) |
-                        ((u32)(data[3] & 0xFF) <<  8) |
-                        (u32)(data[4] & 0xFF);
+                *bit_error = ((u32)(data[1] & 0x0F) << 24) |
+                             ((u32)(data[2] & 0xFF) << 16) |
+                             ((u32)(data[3] & 0xFF) <<  8) |
+                             (u32)(data[4] & 0xFF);
 
                 /* Set SLV-T Bank : 0xA0 */
                 cxd2841er_write_reg(priv, I2C_SLVT, 0x00, 0xa0);
@@ -1413,24 +1402,14 @@ static int cxd2841er_mon_read_ber_s2(struct cxd2841er_priv *priv, u32 *ber)
                                 "%s(): period is 0\n", __func__);
                         return -EINVAL;
                 }
-                if (bit_error > (period * 64800)) {
+                if (*bit_error > (period * 64800)) {
                         dev_dbg(&priv->i2c->dev,
                                 "%s(): invalid bit_err 0x%x period 0x%x\n",
-                                __func__, bit_error, period);
+                                __func__, *bit_error, period);
                         return -EINVAL;
                 }
-                /*
-                 * BER = bitError / (period * 64800)
-                 *      = (bitError * 10^7) / (period * 64800)
-                 *      = (bitError * 10^5) / (period * 648)
-                 *      = (bitError * 12500) / (period * 81)
-                 *      = (bitError * 10) * 1250 / (period * 81)
-                 */
-                temp_q = div_u64_rem(12500ULL * bit_error,
-                                        period * 81, &temp_r);
-                if (temp_r >= period * 40)
-                        temp_q++;
-                *ber = temp_q;
+                *bit_count = period * 64800;
+
                 return 0;
         } else {
                 dev_dbg(&priv->i2c->dev,
@@ -1439,13 +1418,12 @@ static int cxd2841er_mon_read_ber_s2(struct cxd2841er_priv *priv, u32 *ber)
         return -EINVAL;
 }
 
-static int cxd2841er_read_ber_t2(struct cxd2841er_priv *priv, u32 *ber)
+static int cxd2841er_read_ber_t2(struct cxd2841er_priv *priv,
+                                 u32 *bit_error, u32 *bit_count)
 {
         u8 data[4];
-        u32 div, q, r;
-        u32 bit_err, period_exp, n_ldpc;
+        u32 period_exp, n_ldpc;
 
-        *ber = 0;
         if (priv->state != STATE_ACTIVE_TC) {
                 dev_dbg(&priv->i2c->dev,
                         "%s(): invalid state %d\n", __func__, priv->state);
@@ -1456,40 +1434,44 @@ static int cxd2841er_read_ber_t2(struct cxd2841er_priv *priv, u32 *ber)
         if (!(data[0] & 0x10)) {
                 dev_dbg(&priv->i2c->dev,
                         "%s(): no valid BER data\n", __func__);
-                return 0;
+                return -EINVAL;
         }
-        bit_err = ((u32)(data[0] & 0x0f) << 24) |
-                ((u32)data[1] << 16) |
-                ((u32)data[2] << 8) |
-                (u32)data[3];
+        *bit_error = ((u32)(data[0] & 0x0f) << 24) |
+                     ((u32)data[1] << 16) |
+                     ((u32)data[2] << 8) |
+                     (u32)data[3];
         cxd2841er_read_reg(priv, I2C_SLVT, 0x6f, data);
         period_exp = data[0] & 0x0f;
         cxd2841er_write_reg(priv, I2C_SLVT, 0x00, 0x22);
         cxd2841er_read_reg(priv, I2C_SLVT, 0x5e, data);
         n_ldpc = ((data[0] & 0x03) == 0 ? 16200 : 64800);
-        if (bit_err > ((1U << period_exp) * n_ldpc)) {
+        if (*bit_error > ((1U << period_exp) * n_ldpc)) {
                 dev_dbg(&priv->i2c->dev,
                         "%s(): invalid BER value\n", __func__);
                 return -EINVAL;
         }
+
+        /*
+         * FIXME: the right thing would be to return bit_error untouched,
+         * but, as we don't know the scale returned by the counters, let's
+         * at least preserver BER = bit_error/bit_count.
+         */
         if (period_exp >= 4) {
-                div = (1U << (period_exp - 4)) * (n_ldpc / 200);
-                q = div_u64_rem(3125ULL * bit_err, div, &r);
+                *bit_count = (1U << (period_exp - 4)) * (n_ldpc / 200);
+                *bit_error *= 3125ULL;
         } else {
-                div = (1U << period_exp) * (n_ldpc / 200);
-                q = div_u64_rem(50000ULL * bit_err, div, &r);
+                *bit_count = (1U << period_exp) * (n_ldpc / 200);
+                *bit_error *= 50000ULL;;
         }
-        *ber = (r >= div / 2) ? q + 1 : q;
         return 0;
 }
 
-static int cxd2841er_read_ber_t(struct cxd2841er_priv *priv, u32 *ber)
+static int cxd2841er_read_ber_t(struct cxd2841er_priv *priv,
+                                u32 *bit_error, u32 *bit_count)
 {
         u8 data[2];
-        u32 div, q, r;
-        u32 bit_err, period;
+        u32 period;
 
-        *ber = 0;
         if (priv->state != STATE_ACTIVE_TC) {
                 dev_dbg(&priv->i2c->dev,
                         "%s(): invalid state %d\n", __func__, priv->state);
@@ -1503,12 +1485,17 @@ static int cxd2841er_read_ber_t(struct cxd2841er_priv *priv, u32 *ber)
                 return 0;
         }
         cxd2841er_read_regs(priv, I2C_SLVT, 0x22, data, sizeof(data));
-        bit_err = ((u32)data[0] << 8) | (u32)data[1];
+        *bit_error = ((u32)data[0] << 8) | (u32)data[1];
         cxd2841er_read_reg(priv, I2C_SLVT, 0x6f, data);
         period = ((data[0] & 0x07) == 0) ? 256 : (4096 << (data[0] & 0x07));
-        div = period / 128;
-        q = div_u64_rem(78125ULL * bit_err, div, &r);
-        *ber = (r >= div / 2) ? q + 1 : q;
+
+        /*
+         * FIXME: the right thing would be to return bit_error untouched,
+         * but, as we don't know the scale returned by the counters, let's
+         * at least preserver BER = bit_error/bit_count.
+         */
+        *bit_count = period / 128;
+        *bit_error *= 78125ULL;
         return 0;
 }
 
@@ -1722,32 +1709,36 @@ static void cxd2841er_read_ber(struct dvb_frontend *fe)
 {
         struct dtv_frontend_properties *p = &fe->dtv_property_cache;
         struct cxd2841er_priv *priv = fe->demodulator_priv;
-        u32 ber = 0, ret;
+        u32 ret, bit_error = 0, bit_count = 0;
 
         dev_dbg(&priv->i2c->dev, "%s()\n", __func__);
         switch (p->delivery_system) {
         case SYS_DVBS:
-                ret = cxd2841er_mon_read_ber_s(priv, &ber);
+                ret = cxd2841er_mon_read_ber_s(priv, &bit_error, &bit_count);
                 break;
         case SYS_DVBS2:
-                ret = cxd2841er_mon_read_ber_s2(priv, &ber);
+                ret = cxd2841er_mon_read_ber_s2(priv, &bit_error, &bit_count);
                 break;
         case SYS_DVBT:
-                ret = cxd2841er_read_ber_t(priv, &ber);
+                ret = cxd2841er_read_ber_t(priv, &bit_error, &bit_count);
                 break;
         case SYS_DVBT2:
-                ret = cxd2841er_read_ber_t2(priv, &ber);
+                ret = cxd2841er_read_ber_t2(priv, &bit_error, &bit_count);
                 break;
         default:
                 p->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+                p->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
                 return;
         }
 
         if (!ret) {
                 p->post_bit_error.stat[0].scale = FE_SCALE_COUNTER;
-                p->post_bit_error.stat[0].uvalue = ber;
+                p->post_bit_error.stat[0].uvalue = bit_error;
+                p->post_bit_count.stat[0].scale = FE_SCALE_COUNTER;
+                p->post_bit_count.stat[0].uvalue = bit_count;
         } else {
                 p->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+                p->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
         }
 }
 
@@ -2988,6 +2979,7 @@ static int cxd2841er_get_frontend(struct dvb_frontend *fe,
                 p->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
                 p->block_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
                 p->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+                p->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
         }
         return 0;
 }
@@ -3052,6 +3044,7 @@ done:
         p->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
         p->block_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
         p->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+        p->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 
         return ret;
 }
@@ -3426,6 +3419,8 @@ static void cxd2841er_init_stats(struct dvb_frontend *fe)
         p->block_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
         p->post_bit_error.len = 1;
         p->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+        p->post_bit_count.len = 1;
+        p->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 }