Re: [dpdk-dev] [PATCH v2 4/6] baseband/acc100: add support for 4G CRC drop

[Tom Rix]

On 9/7/21 6:04 PM, Chautru, Nicolas wrote:

-----Original Message-----
From: Tom Rix <t...@redhat.com>
Sent: Wednesday, September 1, 2021 7:20 AM
To: Chautru, Nicolas <nicolas.chau...@intel.com>; dev@dpdk.org;
gak...@marvell.com
Cc: tho...@monjalon.net; hemant.agra...@nxp.com; Zhang, Mingshan
<mingshan.zh...@intel.com>; Joshi, Arun <arun.jo...@intel.com>
Subject: Re: [PATCH v2 4/6] baseband/acc100: add support for 4G CRC drop


On 8/19/21 2:10 PM, Nicolas Chautru wrote:

This implements in PMD the option to drop the CB CRC after 4G decoding
to help transport block concatenation.

Signed-off-by: Nicolas Chautru <nicolas.chau...@intel.com>
---
   doc/guides/bbdevs/acc100.rst             |  1 +
   doc/guides/rel_notes/release_21_11.rst   |  4 ++++
   drivers/baseband/acc100/rte_acc100_pmd.c | 12 +++++++++---
   3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/doc/guides/bbdevs/acc100.rst
b/doc/guides/bbdevs/acc100.rst index ff0fa4b..9fff6ab 100644
--- a/doc/guides/bbdevs/acc100.rst
+++ b/doc/guides/bbdevs/acc100.rst
@@ -58,6 +58,7 @@ ACC100 5G/4G FEC PMD supports the following BBDEV

capabilities:

      - ``RTE_BBDEV_TURBO_NEG_LLR_1_BIT_IN`` :  set if negative LLR

encoder i/p is supported

      - ``RTE_BBDEV_TURBO_POS_LLR_1_BIT_IN`` :  set if positive LLR encoder

i/p is supported

      - ``RTE_BBDEV_TURBO_DEC_TB_CRC_24B_KEEP`` :  keep CRC24B bits
appended while decoding
+   - ``RTE_BBDEV_TURBO_DEC_CRC_24B_DROP`` : option to drop the code
+ block CRC after decoding
      - ``RTE_BBDEV_TURBO_EARLY_TERMINATION`` :  set early termination

feature

      - ``RTE_BBDEV_TURBO_DEC_SCATTER_GATHER`` :  supports scatter-

gather for input/output data

      - ``RTE_BBDEV_TURBO_HALF_ITERATION_EVEN`` :  set half iteration
granularity diff --git a/doc/guides/rel_notes/release_21_11.rst
b/doc/guides/rel_notes/release_21_11.rst
index 8ca59b7..f7843bc 100644
--- a/doc/guides/rel_notes/release_21_11.rst
+++ b/doc/guides/rel_notes/release_21_11.rst
@@ -59,6 +59,10 @@ New Features

     Added support for more comprehensive CRC options.

+* **Updated the ACC100 bbdev PMD.**
+
+  Added support for more comprehensive CRC options.
+
   Removed Items
   -------------

diff --git a/drivers/baseband/acc100/rte_acc100_pmd.c
b/drivers/baseband/acc100/rte_acc100_pmd.c
index 68ba523..891be81 100644
--- a/drivers/baseband/acc100/rte_acc100_pmd.c
+++ b/drivers/baseband/acc100/rte_acc100_pmd.c
@@ -980,6 +980,7 @@

        RTE_BBDEV_TURBO_NEG_LLR_1_BIT_IN |

                                        RTE_BBDEV_TURBO_MAP_DEC |

        RTE_BBDEV_TURBO_DEC_TB_CRC_24B_KEEP |

+

        RTE_BBDEV_TURBO_DEC_CRC_24B_DROP |
        RTE_BBDEV_TURBO_DEC_SCATTER_GATHER,

                                .max_llr_modulus = INT8_MAX,
                                .num_buffers_src =
@@ -1708,8 +1709,12 @@
        }

        if ((op->turbo_dec.code_block_mode ==

RTE_BBDEV_TRANSPORT_BLOCK)

-               && !check_bit(op->turbo_dec.op_flags,
-               RTE_BBDEV_TURBO_DEC_TB_CRC_24B_KEEP))
+                       && !check_bit(op->turbo_dec.op_flags,
+                       RTE_BBDEV_TURBO_DEC_TB_CRC_24B_KEEP))
+               crc24_overlap = 24;
+       if ((op->turbo_dec.code_block_mode == RTE_BBDEV_CODE_BLOCK)

These two if-statements can be combined.

They could but really when I tried  that became arguably unreadable, I thought 
it was still better this way.

Ok

Tom

+                       && check_bit(op->turbo_dec.op_flags,
+                       RTE_BBDEV_TURBO_DEC_CRC_24B_DROP))
                crc24_overlap = 24;

        /* Calculates circular buffer size.
@@ -1744,7 +1749,8 @@

        next_triplet = acc100_dma_fill_blk_type_out(
                        desc, h_output, *h_out_offset,
-                       k >> 3, next_triplet,

ACC100_DMA_BLKID_OUT_HARD);

+                       (k - crc24_overlap)  >> 3, next_triplet,

crc24_overlap had been set before this patch in the above if-statement for
crc_24b_keep.

so this looks like a bug.

If it is a bug, it should be separated out as its own patch.

Ok fair enough, will do. Thanks

Tom

+                       ACC100_DMA_BLKID_OUT_HARD);
        if (unlikely(next_triplet < 0)) {
                rte_bbdev_log(ERR,
                                "Mismatch between data to process and

mbuf data length in

bbdev_op: %p",