RE: [PATCH v6 net-next 4/6] net: fec: add rx_frame_size to support configurable RX length

[Wei Fang]

> Add a new rx_frame_size member in the fec_enet_private structure to
> track the RX buffer size. On the Jumbo frame enabled system, the value
> will be recalculated whenever the MTU is updated, allowing the driver
> to allocate RX buffer efficiently.
> 
> Configure the TRUNC_FL (Frame Truncation Length) based on the smaller
> value between max_buf_size and the rx_frame_size to maintain consistent
> RX error behavior, regardless of whether Jumbo frames are enabled.
> 
> Signed-off-by: Shenwei Wang <shenwei.wang@xxxxxxx>
> ---
>  drivers/net/ethernet/freescale/fec.h      | 1 +
>  drivers/net/ethernet/freescale/fec_main.c | 3 ++-
>  2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fec.h
> b/drivers/net/ethernet/freescale/fec.h
> index 47317346b2f3..f1032a11aa76 100644
> --- a/drivers/net/ethernet/freescale/fec.h
> +++ b/drivers/net/ethernet/freescale/fec.h
> @@ -621,6 +621,7 @@ struct fec_enet_private {
>  	unsigned int total_rx_ring_size;
>  	unsigned int max_buf_size;
>  	unsigned int pagepool_order;
> +	unsigned int rx_frame_size;
> 
>  	struct	platform_device *pdev;
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index 5b71c4cf86bc..df8b69af5296 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -1192,7 +1192,7 @@ fec_restart(struct net_device *ndev)
>  		else
>  			val &= ~FEC_RACC_OPTIONS;
>  		writel(val, fep->hwp + FEC_RACC);
> -		writel(fep->max_buf_size, fep->hwp + FEC_FTRL);
> +		writel(min(fep->rx_frame_size, fep->max_buf_size), fep->hwp +
> FEC_FTRL);
>  	}
>  #endif
> 
> @@ -4562,6 +4562,7 @@ fec_probe(struct platform_device *pdev)
>  	pinctrl_pm_select_sleep_state(&pdev->dev);
> 
>  	fep->pagepool_order = 0;
> +	fep->rx_frame_size = FEC_ENET_RX_FRSIZE;
>  	fep->max_buf_size = PKT_MAXBUF_SIZE;
>  	ndev->max_mtu = fep->max_buf_size - ETH_HLEN - ETH_FCS_LEN;
> 
> --
> 2.43.0

Reviewed-by: Wei Fang <wei.fang@xxxxxxx>