Re: [PATCH net-next v3] net: stmmac: dwxgmac2: enable L2 split header support

[Sagar Cheluvegowda <sagar.cheluvegowda@oss.qualcomm.com>]

>> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c
>> index 6719ac6e395b..65ac5403ec58 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c
>> @@ -292,8 +292,18 @@ static int dwxgmac2_get_rx_hash(struct dma_desc *p, u32 *hash,
>>  
>>  static void dwxgmac2_get_rx_header_len(struct dma_desc *p, unsigned int *len)
>>  {
>> -	if (le32_to_cpu(p->des3) & XGMAC_RDES3_L34T)
>> +	u32 rdes3 = le32_to_cpu(p->des3);
>> +
>> +	/* when FD=1 and LD=0, HL is RDES2[9:0] */
>> +	if (!(rdes3 & XGMAC_RDES3_LD)) {
>> +		*len = le32_to_cpu(p->des2) & XGMAC_RDES2_HL;
>> +		return;
>> +	}
>> +
>> +	if (rdes3 & XGMAC_RDES3_L34T)
> should we check FD=1 here? Since HL is not defined for the case {FD=0,LD=1},
> right?
>
>>  		*len = le32_to_cpu(p->des2) & XGMAC_RDES2_HL;
>> +	else if (rdes3 & XGMAC_RDES3_L2T)
>> +		*len = (le32_to_cpu(p->des2) & XGMAC_RDES2_NONIPHL) >> 2;
> same here.
>
> Regards,
> Lorenzo
>
Hi Lorenzo,

Thanks for the review. dwxgmac2_get_rx_header_len() is only called from stmmac_rx_buf1_len(),
after the sph_active && len early return, so with split header enabled it only runs on the
first descriptor (FD=1). I don't think an extra FD check is needed, but I can add one if you'd prefer.

Regards,
Sagar