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From: Nicolas Chautru <nicolas.chautru@intel.com>
To: dev@dpdk.org, gakhil@marvell.com
Cc: thomas@monjalon.net, trix@redhat.com, hemant.agrawal@nxp.com,
	mingshan.zhang@intel.com,
	Nicolas Chautru <nicolas.chautru@intel.com>
Subject: [dpdk-dev] [PATCH v1 5/6] doc: clarification of usage of HARQ in bbdev doc
Date: Fri, 13 Aug 2021 09:51:24 -0700	[thread overview]
Message-ID: <1628873485-30596-6-git-send-email-nicolas.chautru@intel.com> (raw)
In-Reply-To: <1628873485-30596-1-git-send-email-nicolas.chautru@intel.com>

New paragraph detailing typical VRAN usecase and mapping
to bbdev API usage.

Signed-off-by: Nicolas Chautru <nicolas.chautru@intel.com>
---
 doc/guides/prog_guide/bbdev.rst | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/doc/guides/prog_guide/bbdev.rst b/doc/guides/prog_guide/bbdev.rst
index 8bd7cba..d48c9a0 100644
--- a/doc/guides/prog_guide/bbdev.rst
+++ b/doc/guides/prog_guide/bbdev.rst
@@ -1054,6 +1054,29 @@ 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. typicallly 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 not 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 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.
 
-- 
1.8.3.1


  parent reply	other threads:[~2021-08-13 16:52 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-13 16:51 [dpdk-dev] [PATCH v1 0/6] bbdev update related to CRC usage Nicolas Chautru
2021-08-13 16:51 ` [dpdk-dev] [PATCH v1 1/6] bbdev: add capability for CRC16 check Nicolas Chautru
2021-10-11 20:17   ` Thomas Monjalon
2021-10-11 20:38     ` Chautru, Nicolas
2021-10-12  6:53       ` Thomas Monjalon
2021-10-12 16:36         ` Chautru, Nicolas
2021-10-12 16:59           ` Thomas Monjalon
2021-08-13 16:51 ` [dpdk-dev] [PATCH v1 2/6] baseband/turbo_sw: add support for CRC16 Nicolas Chautru
2021-08-13 16:51 ` [dpdk-dev] [PATCH v1 3/6] bbdev: add capability for 4G CB CRC DROP Nicolas Chautru
2021-08-13 16:51 ` [dpdk-dev] [PATCH v1 4/6] baseband/acc100: add support for 4G CRC drop Nicolas Chautru
2021-08-13 16:51 ` Nicolas Chautru [this message]
2021-08-13 16:51 ` [dpdk-dev] [PATCH v1 6/6] bbdev: reduce warning level for one scenario Nicolas Chautru

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