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

[Tom Rix <trix@redhat.com>]

On 9/7/21 6:04 PM, Chautru, Nicolas wrote:
>
>> -----Original Message-----
>> From: Tom Rix <trix@redhat.com>
>> Sent: Wednesday, September 1, 2021 7:20 AM
>> To: Chautru, Nicolas <nicolas.chautru@intel.com>; dev@dpdk.org;
>> gakhil@marvell.com
>> Cc: thomas@monjalon.net; hemant.agrawal@nxp.com; Zhang, Mingshan
>> <mingshan.zhang@intel.com>; Joshi, Arun <arun.joshi@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.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.
> 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",