ethdev: introduce shared Rx queue

[dpdk.git] / doc / guides / prog_guide / bbdev.rst

diff --git a/doc/guides/prog_guide/bbdev.rst b/doc/guides/prog_guide/bbdev.rst
index d39167a..70fa01a 100644 (file)
--- a/doc/guides/prog_guide/bbdev.rst
+++ b/doc/guides/prog_guide/bbdev.rst
@@ -13,7 +13,7 @@ optimized libraries to appear as virtual bbdev devices.
 The functional scope of the BBDEV library are those functions in relation to
 the 3GPP Layer 1 signal processing (channel coding, modulation, ...).
 
-The framework currently only supports Turbo Code FEC function.
+The framework currently only supports FEC function.
 
 
 Design Principles
@@ -639,7 +639,7 @@ optionally the ``soft_output`` mbuf data pointers.
    "soft output","soft LLR output buffer (optional)"
    "op_flags","bitmask of all active operation capabilities"
    "rv_index","redundancy version index [0..3]"
-   "iter_max","maximum number of iterations to perofrm in decode all CBs"
+   "iter_max","maximum number of iterations to perform in decode all CBs"
    "iter_min","minimum number of iterations to perform in decoding all CBs"
    "iter_count","number of iterations to performed in decoding all CBs"
    "ext_scale","scale factor on extrinsic info (5 bits)"
@@ -891,6 +891,9 @@ given below.
 |RTE_BBDEV_LDPC_CRC_TYPE_24B_DROP                                    |
 | Set to drop the last CRC bits decoding output                      |
 +--------------------------------------------------------------------+
+|RTE_BBDEV_LDPC_CRC_TYPE_16_CHECK                                    |
+| Set for code block CRC-16 checking                                 |
++--------------------------------------------------------------------+
 |RTE_BBDEV_LDPC_DEINTERLEAVER_BYPASS                                 |
 | Set for bit-level de-interleaver bypass on input stream            |
 +--------------------------------------------------------------------+
@@ -927,9 +930,11 @@ given below.
 +--------------------------------------------------------------------+
 |RTE_BBDEV_LDPC_HARQ_6BIT_COMPRESSION                                |
 | Set if a device supports input/output HARQ compression             |
+| Data is packed as 6 bits by dropping and saturating the MSBs       |
 +--------------------------------------------------------------------+
 |RTE_BBDEV_LDPC_LLR_COMPRESSION                                      |
 | Set if a device supports input LLR compression                     |
+| Data is packed as 6 bits by dropping and saturating the MSBs       |
 +--------------------------------------------------------------------+
 |RTE_BBDEV_LDPC_INTERNAL_HARQ_MEMORY_IN_ENABLE                       |
 | Set if a device supports HARQ input to device's internal memory    |
@@ -1049,6 +1054,37 @@ capability RTE_BBDEV_LDPC_INTERNAL_HARQ_MEMORY_OUT_ENABLE is set
 then the HARQ is stored in memory internal to the device and not visible
 to BBDEV.
 
+.. note::
+
+    More explicitly for a typical usage of HARQ retransmission
+    in a VRAN application using a HW PMD, there will be 2 cases.
+
+    For 1st transmission, only the HARQ output is enabled:
+
+    - the harq_combined_output.offset is provided to a given address.
+      ie. typically an integer index * 32K,
+      where the index is tracked by the application based on code block index
+      for a given UE and HARQ process.
+
+    - the related operation flag would notably include
+      RTE_BBDEV_LDPC_HQ_COMBINE_OUT_ENABLE and RTE_BBDEV_LDPC_HARQ_6BIT_COMPRESSION.
+
+    - note that no explicit flush or reset of the memory is required.
+
+    For 2nd transmission, an input is also required to benefit from HARQ combination gain:
+
+    - the changes mentioned above are the same (note that rvIndex may be adjusted).
+
+    - the operation flag would additionally include the LDPC_HQ_COMBINE_IN_ENABLE flag.
+
+    - the harq_combined_input.offset must be set to the address of the related code block
+      (ie. same as the harq_combine_output index above for the same code block, HARQ process, UE).
+
+    - the harq_combined_input.length must be set to the length
+      which was provided back in the related harq_combined_output.length
+      when it has processed and dequeued (previous HARQ iteration).
+
+
 The output mbuf data structures are expected to be allocated by the
 application with enough room for the output data.