ayufan: stmmac: disable TX offload for mtu bigger than 1498

arch/arm64/boot/dts/rockchip/rk3328-rock64.dts

@@ -170,7 +170,7 @@ &gmac2io {
 	phy-mode = "rgmii";
 	pinctrl-names = "default";
 	pinctrl-0 = <&rgmiim1_pins>;
-	snps,force_thresh_dma_mode;
+	rockchip,bugged_tx_coe;
 	snps,reset-gpio = <&gpio1 RK_PC2 GPIO_ACTIVE_LOW>;
 	snps,reset-active-low;
 	snps,reset-delays-us = <0 10000 50000>;

arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dts

@@ -265,7 +265,7 @@ &gmac {
 	phy-mode = "rgmii";
 	pinctrl-names = "default";
 	pinctrl-0 = <&rgmii_pins>;
-	snps,force_thresh_dma_mode;
+	rockchip,bugged_tx_coe;
 	snps,reset-gpio = <&gpio3 RK_PB7 GPIO_ACTIVE_LOW>;
 	snps,reset-active-low;
 	snps,reset-delays-us = <0 10000 50000>;

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -3629,6 +3629,10 @@ static netdev_features_t stmmac_fix_features(struct net_device *dev,
 	if (priv->plat->bugged_jumbo && (dev->mtu > ETH_DATA_LEN))
 		features &= ~NETIF_F_CSUM_MASK;
 
+	/* Including very small MTUs of 1498 for Rockchip devices */
+	if (priv->plat->bugged_tx_coe && (dev->mtu > ETH_DATA_LEN - 2))
+		features &= ~NETIF_F_CSUM_MASK;
+
 	/* Disable tso if asked by ethtool */
 	if ((priv->plat->tso_en) && (priv->dma_cap.tsoen)) {
 		if (features & NETIF_F_TSO)

drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c

@@ -516,6 +516,8 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac)
 		pr_warn("force_sf_dma_mode is ignored if force_thresh_dma_mode is set.");
 	}
 
+	plat->bugged_tx_coe = of_property_read_bool(np, "rockchip,bugged_tx_coe");
+
 	of_property_read_u32(np, "snps,ps-speed", &plat->mac_port_sel_speed);
 
 	plat->axi = stmmac_axi_setup(pdev);

include/linux/stmmac.h

@@ -162,6 +162,7 @@ struct plat_stmmacenet_data {
 	int pmt;
 	int force_sf_dma_mode;
 	int force_thresh_dma_mode;
+	int bugged_tx_coe;
 	int riwt_off;
 	int max_speed;
 	int maxmtu;