1 files changed, 245 insertions, 0 deletions
diff --git a/Documentation/media/uapi/dvb/frontend-stat-properties.rst b/Documentation/media/uapi/dvb/frontend-stat-properties.rst
new file mode 100644
index 000000000..e73754fd0
--- /dev/null
+++ b/Documentation/media/uapi/dvb/frontend-stat-properties.rst
@@ -0,0 +1,245 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _frontend-stat-properties:
+
+******************************
+Frontend statistics indicators
+******************************
+
+The values are returned via ``dtv_property.stat``. If the property is
+supported, ``dtv_property.stat.len`` is bigger than zero.
+
+For most delivery systems, ``dtv_property.stat.len`` will be 1 if the
+stats is supported, and the properties will return a single value for
+each parameter.
+
+It should be noted, however, that new OFDM delivery systems like ISDB
+can use different modulation types for each group of carriers. On such
+standards, up to 3 groups of statistics can be provided, and
+``dtv_property.stat.len`` is updated to reflect the "global" metrics,
+plus one metric per each carrier group (called "layer" on ISDB).
+
+So, in order to be consistent with other delivery systems, the first
+value at :c:type:`dtv_property.stat.dtv_stats <dtv_stats>` array refers
+to the global metric. The other elements of the array represent each
+layer, starting from layer A(index 1), layer B (index 2) and so on.
+
+The number of filled elements are stored at ``dtv_property.stat.len``.
+
+Each element of the ``dtv_property.stat.dtv_stats`` array consists on
+two elements:
+
+-  ``svalue`` or ``uvalue``, where ``svalue`` is for signed values of
+   the measure (dB measures) and ``uvalue`` is for unsigned values
+   (counters, relative scale)
+
+-  ``scale`` - Scale for the value. It can be:
+
+   -  ``FE_SCALE_NOT_AVAILABLE`` - The parameter is supported by the
+      frontend, but it was not possible to collect it (could be a
+      transitory or permanent condition)
+
+   -  ``FE_SCALE_DECIBEL`` - parameter is a signed value, measured in
+      1/1000 dB
+
+   -  ``FE_SCALE_RELATIVE`` - parameter is a unsigned value, where 0
+      means 0% and 65535 means 100%.
+
+   -  ``FE_SCALE_COUNTER`` - parameter is a unsigned value that counts
+      the occurrence of an event, like bit error, block error, or lapsed
+      time.
+
+
+.. _DTV-STAT-SIGNAL-STRENGTH:
+
+DTV_STAT_SIGNAL_STRENGTH
+========================
+
+Indicates the signal strength level at the analog part of the tuner or
+of the demod.
+
+Possible scales for this metric are:
+
+-  ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
+   measurement was not complete yet.
+
+-  ``FE_SCALE_DECIBEL`` - signal strength is in 0.001 dBm units, power
+   measured in miliwatts. This value is generally negative.
+
+-  ``FE_SCALE_RELATIVE`` - The frontend provides a 0% to 100%
+   measurement for power (actually, 0 to 65535).
+
+
+.. _DTV-STAT-CNR:
+
+DTV_STAT_CNR
+============
+
+Indicates the Signal to Noise ratio for the main carrier.
+
+Possible scales for this metric are:
+
+-  ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
+   measurement was not complete yet.
+
+-  ``FE_SCALE_DECIBEL`` - Signal/Noise ratio is in 0.001 dB units.
+
+-  ``FE_SCALE_RELATIVE`` - The frontend provides a 0% to 100%
+   measurement for Signal/Noise (actually, 0 to 65535).
+
+
+.. _DTV-STAT-PRE-ERROR-BIT-COUNT:
+
+DTV_STAT_PRE_ERROR_BIT_COUNT
+============================
+
+Measures the number of bit errors before the forward error correction
+(FEC) on the inner coding block (before Viterbi, LDPC or other inner
+code).
+
+This measure is taken during the same interval as
+``DTV_STAT_PRE_TOTAL_BIT_COUNT``.
+
+In order to get the BER (Bit Error Rate) measurement, it should be
+divided by
+:ref:`DTV_STAT_PRE_TOTAL_BIT_COUNT <DTV-STAT-PRE-TOTAL-BIT-COUNT>`.
+
+This measurement is monotonically increased, as the frontend gets more
+bit count measurements. The frontend may reset it when a
+channel/transponder is tuned.
+
+Possible scales for this metric are:
+
+-  ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
+   measurement was not complete yet.
+
+-  ``FE_SCALE_COUNTER`` - Number of error bits counted before the inner
+   coding.
+
+
+.. _DTV-STAT-PRE-TOTAL-BIT-COUNT:
+
+DTV_STAT_PRE_TOTAL_BIT_COUNT
+============================
+
+Measures the amount of bits received before the inner code block, during
+the same period as
+:ref:`DTV_STAT_PRE_ERROR_BIT_COUNT <DTV-STAT-PRE-ERROR-BIT-COUNT>`
+measurement was taken.
+
+It should be noted that this measurement can be smaller than the total
+amount of bits on the transport stream, as the frontend may need to
+manually restart the measurement, losing some data between each
+measurement interval.
+
+This measurement is monotonically increased, as the frontend gets more
+bit count measurements. The frontend may reset it when a
+channel/transponder is tuned.
+
+Possible scales for this metric are:
+
+-  ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
+   measurement was not complete yet.
+
+-  ``FE_SCALE_COUNTER`` - Number of bits counted while measuring
+   :ref:`DTV_STAT_PRE_ERROR_BIT_COUNT <DTV-STAT-PRE-ERROR-BIT-COUNT>`.
+
+
+.. _DTV-STAT-POST-ERROR-BIT-COUNT:
+
+DTV_STAT_POST_ERROR_BIT_COUNT
+=============================
+
+Measures the number of bit errors after the forward error correction
+(FEC) done by inner code block (after Viterbi, LDPC or other inner
+code).
+
+This measure is taken during the same interval as
+``DTV_STAT_POST_TOTAL_BIT_COUNT``.
+
+In order to get the BER (Bit Error Rate) measurement, it should be
+divided by
+:ref:`DTV_STAT_POST_TOTAL_BIT_COUNT <DTV-STAT-POST-TOTAL-BIT-COUNT>`.
+
+This measurement is monotonically increased, as the frontend gets more
+bit count measurements. The frontend may reset it when a
+channel/transponder is tuned.
+
+Possible scales for this metric are:
+
+-  ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
+   measurement was not complete yet.
+
+-  ``FE_SCALE_COUNTER`` - Number of error bits counted after the inner
+   coding.
+
+
+.. _DTV-STAT-POST-TOTAL-BIT-COUNT:
+
+DTV_STAT_POST_TOTAL_BIT_COUNT
+=============================
+
+Measures the amount of bits received after the inner coding, during the
+same period as
+:ref:`DTV_STAT_POST_ERROR_BIT_COUNT <DTV-STAT-POST-ERROR-BIT-COUNT>`
+measurement was taken.
+
+It should be noted that this measurement can be smaller than the total
+amount of bits on the transport stream, as the frontend may need to
+manually restart the measurement, losing some data between each
+measurement interval.
+
+This measurement is monotonically increased, as the frontend gets more
+bit count measurements. The frontend may reset it when a
+channel/transponder is tuned.
+
+Possible scales for this metric are:
+
+-  ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
+   measurement was not complete yet.
+
+-  ``FE_SCALE_COUNTER`` - Number of bits counted while measuring
+   :ref:`DTV_STAT_POST_ERROR_BIT_COUNT <DTV-STAT-POST-ERROR-BIT-COUNT>`.
+
+
+.. _DTV-STAT-ERROR-BLOCK-COUNT:
+
+DTV_STAT_ERROR_BLOCK_COUNT
+==========================
+
+Measures the number of block errors after the outer forward error
+correction coding (after Reed-Solomon or other outer code).
+
+This measurement is monotonically increased, as the frontend gets more
+bit count measurements. The frontend may reset it when a
+channel/transponder is tuned.
+
+Possible scales for this metric are:
+
+-  ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
+   measurement was not complete yet.
+
+-  ``FE_SCALE_COUNTER`` - Number of error blocks counted after the outer
+   coding.
+
+
+.. _DTV-STAT-TOTAL-BLOCK-COUNT:
+
+DTV-STAT_TOTAL_BLOCK_COUNT
+==========================
+
+Measures the total number of blocks received during the same period as
+:ref:`DTV_STAT_ERROR_BLOCK_COUNT <DTV-STAT-ERROR-BLOCK-COUNT>`
+measurement was taken.
+
+It can be used to calculate the PER indicator, by dividing
+:ref:`DTV_STAT_ERROR_BLOCK_COUNT <DTV-STAT-ERROR-BLOCK-COUNT>` by
+:ref:`DTV-STAT-TOTAL-BLOCK-COUNT`.
+
+Possible scales for this metric are:
+
+-  ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
+   measurement was not complete yet.
+
+-  ``FE_SCALE_COUNTER`` - Number of blocks counted while measuring
+   :ref:`DTV_STAT_ERROR_BLOCK_COUNT <DTV-STAT-ERROR-BLOCK-COUNT>`.