RE: [PATCH iwl-net] igc: Fix hicredit calculation

From: Chilakala, Mallikarjuna
Date: Sat Dec 09 2023 - 12:22:22 EST


Rodrigo Cataldo via B4 Relay
<devnull+rodrigo.cadore.l-acoustics.com@xxxxxxxxxx> writes:

> From: Rodrigo Cataldo <rodrigo.cadore@xxxxxxxxxxxxxxx>
>
> According to the Intel Software Manual for I225, Section 7.5.2.7,
> hicredit should be multiplied by the constant link-rate value, 0x7736.
>
> Currently, the old constant link-rate value, 0x7735, from the boards
> supported on igb are being used, most likely due to a copy'n'paste, as
> the rest of the logic is the same for both drivers.
>
> Update hicredit accordingly.
>
> Fixes: 1ab011b0bf07 ("igc: Add support for CBS offloading")
> Reviewed-by: Kurt Kanzenbach <kurt@xxxxxxxxxxxxx>
> Signed-off-by: Rodrigo Cataldo <rodrigo.cadore@xxxxxxxxxxxxxxx>
> ---

Looks good to me!
Acked-by: Malli Chilakala <mallikarjuna.chilakala@xxxxxxxxx>

> This is a simple fix for the credit calculation on igc devices
> (i225/i226) to match the Intel software manual.
>
> This is my first contribution to the Linux Kernel. Apologies for any
> mistakes and let me know if I improve anything.
> ---
> drivers/net/ethernet/intel/igc/igc_tsn.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c
> b/drivers/net/ethernet/intel/igc/igc_tsn.c
> index a9c08321aca9..22cefb1eeedf 100644
> --- a/drivers/net/ethernet/intel/igc/igc_tsn.c
> +++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
> @@ -227,7 +227,7 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
> wr32(IGC_TQAVCC(i), tqavcc);
>
> wr32(IGC_TQAVHC(i),
> - 0x80000000 + ring->hicredit * 0x7735);
> + 0x80000000 + ring->hicredit * 0x7736);
> } else {
> /* Disable any CBS for the queue */
> txqctl &= ~(IGC_TXQCTL_QAV_SEL_MASK);
>
> ---
> base-commit: 2078a341f5f609d55667c2dc6337f90d8f322b8f
> change-id: 20231206-igc-fix-hicredit-calc-028bf73c50a8
>
> Best regards,
> --
> Rodrigo Cataldo <rodrigo.cadore@xxxxxxxxxxxxxxx>
>