On 18/02/2020 23:10, Carlos de Paula wrote: > Some rockchip SoCs like the RK3399 and RK3328 exhibit an issue > where tx checksumming does not work with packets larger than 1498. > > The default Programmable Buffer Length for TX in these GMAC's is > not suitable for MTUs higher than 1498. The workaround is to disable > TX offloading with 'ethtool -K eth0 tx off rx off' causing performance > impacts as it disables hardware checksumming. > > This patch sets snps,txpbl to 0x4 which is a safe number tested ok for > the most popular MTU value of 1500. I don't know what this option says, why not specify a mtu in the DT? The hardware limitation will be more clear, no? > For reference, see https://lkml.org/lkml/2019/4/1/1382. > > Signed-off-by: Carlos de Paula <me@xxxxxxxxxxxxx> > --- > arch/arm64/boot/dts/rockchip/rk3328.dtsi | 2 ++ > arch/arm64/boot/dts/rockchip/rk3399.dtsi | 1 + > 2 files changed, 3 insertions(+) > > diff --git a/arch/arm64/boot/dts/rockchip/rk3328.dtsi b/arch/arm64/boot/dts/rockchip/rk3328.dtsi > index 1f53ead52c7f..b7f1de4b7fd0 100644 > --- a/arch/arm64/boot/dts/rockchip/rk3328.dtsi > +++ b/arch/arm64/boot/dts/rockchip/rk3328.dtsi > @@ -906,6 +906,7 @@ > resets = <&cru SRST_GMAC2IO_A>; > reset-names = "stmmaceth"; > rockchip,grf = <&grf>; > + snps,txpbl = <0x4>; > status = "disabled"; > }; > > @@ -913,6 +914,7 @@ > compatible = "rockchip,rk3328-gmac"; > reg = <0x0 0xff550000 0x0 0x10000>; > rockchip,grf = <&grf>; > + snps,txpbl = <0x4>; > interrupts = <GIC_SPI 21 IRQ_TYPE_LEVEL_HIGH>; > interrupt-names = "macirq"; > clocks = <&cru SCLK_MAC2PHY_SRC>, <&cru SCLK_MAC2PHY_RXTX>, > diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi > index 33cc21fcf4c1..cd5415d7e559 100644 > --- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi > +++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi > @@ -288,6 +288,7 @@ > resets = <&cru SRST_A_GMAC>; > reset-names = "stmmaceth"; > rockchip,grf = <&grf>; > + snps,txpbl = <0x4>; > status = "disabled"; > }; > > -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
