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

[Tom Rix <trix@redhat.com>]

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.chautru@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.
> +			&& 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.

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",