arm64: dts: rockchip: Add txpbl node for RK3399/RK3328
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Message ID 20200218221040.10955-1-me@carlosedp.com
State New
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Series
  • arm64: dts: rockchip: Add txpbl node for RK3399/RK3328
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Commit Message

Carlos Eduardo de Paula Feb. 18, 2020, 10:10 p.m. UTC
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.

For reference, see https://lkml.org/lkml/2019/4/1/1382.

Signed-off-by: Carlos de Paula <me@carlosedp.com>
---
 arch/arm64/boot/dts/rockchip/rk3328.dtsi | 2 ++
 arch/arm64/boot/dts/rockchip/rk3399.dtsi | 1 +
 2 files changed, 3 insertions(+)

Comments

Heiko Stuebner March 1, 2020, 12:25 a.m. UTC | #1
Am Dienstag, 18. Februar 2020, 23:10:37 CET schrieb Carlos de Paula:
> 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.
> 
> For reference, see https://lkml.org/lkml/2019/4/1/1382.
> 
> Signed-off-by: Carlos de Paula <me@carlosedp.com>

applied for 5.7

Thanks
Heiko
Leonidas P. March 1, 2020, 2:06 a.m. UTC | #2
I am also in favor of this but I think we should remove the line that 
specifies the txpbl in the rk3328-roc-cc.dts gmac2io since it will get 
applied here in the .dtsi
Daniel Lezcano March 1, 2020, 8:22 a.m. UTC | #3
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@carlosedp.com>
> ---
>  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";
>  	};
>  
>
Daniel Lezcano March 1, 2020, 9:02 a.m. UTC | #4
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.

What about using something like:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/net/marvell-armada-370-neta.txt#n16

or

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/net/ethernet-controller.yaml#n37

?

> For reference, see https://lkml.org/lkml/2019/4/1/1382.
> 
> Signed-off-by: Carlos de Paula <me@carlosedp.com>
> ---
>  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";
>  	};
>  
>

Patch
diff mbox series

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";
 	};