On Thu, Oct 29, 2020 at 02:39:15PM +0800, DENG Qingfang wrote:
> MT762x HW supports frame length up to 2048 (maximum length on GDM),
> so allow setting MTU up to 2030.
>
> Signed-off-by: DENG Qingfang <[email protected]>
> ---
>
> I only tested this on MT7621, no sure if it is applicable for other SoCs
> especially MT7628, which has an old IP.
>
> ---
> drivers/net/ethernet/mediatek/mtk_eth_soc.c | 31 ++++++++++++++++++++-
> drivers/net/ethernet/mediatek/mtk_eth_soc.h | 11 ++++++--
> 2 files changed, 38 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> index 6d2d60675ffd..a0c56d9be1d5 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> @@ -353,7 +353,7 @@ static void mtk_mac_config(struct phylink_config *config,
> unsigned int mode,
> /* Setup gmac */
> mcr_cur = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id));
> mcr_new = mcr_cur;
> - mcr_new |= MAC_MCR_MAX_RX_1536 | MAC_MCR_IPG_CFG | MAC_MCR_FORCE_MODE |
> + mcr_new |= MAC_MCR_IPG_CFG | MAC_MCR_FORCE_MODE |
> MAC_MCR_BACKOFF_EN | MAC_MCR_BACKPR_EN | MAC_MCR_FORCE_LINK;
Since you no longer set MAC_MCR_MAX_RX_1536, what does the hardware
default to?
> /* Only update control register when needed! */
> @@ -2499,6 +2499,34 @@ static void mtk_uninit(struct net_device *dev)
> mtk_rx_irq_disable(eth, ~0);
> }
>
> +static int mtk_change_mtu(struct net_device *dev, int new_mtu)
> +{
> + struct mtk_mac *mac = netdev_priv(dev);
> + u32 mcr_cur, mcr_new;
> + int length;
> +
> + mcr_cur = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id));
> + mcr_new = mcr_cur & ~MAC_MCR_MAX_RX_LEN_MASK;
> + length = new_mtu + MTK_RX_ETH_HLEN;
> +
> + if (length <= 1518)
> + mcr_new |= MAC_MCR_MAX_RX_LEN(MAC_MCR_MAX_RX_LEN_1518);
> + else if (length <= 1536)
> + mcr_new |= MAC_MCR_MAX_RX_LEN(MAC_MCR_MAX_RX_LEN_1536);
> + else if (length <= 1552)
> + mcr_new |= MAC_MCR_MAX_RX_LEN(MAC_MCR_MAX_RX_LEN_1552);
> + else
> + mcr_new |= MAC_MCR_MAX_RX_LEN(MAC_MCR_MAX_RX_LEN_2048);
You should have another if here, and return -EIVAL is the user asked
for an MTU of 2049 of greater.
Andrew
