target/linux/rockchip/patches-5.4/004-arm64-dts-rockchip-Add-txpbl-node-for-RK3399-RK3328.patch

   1 From 8a469ee35606ba65448d54e5a2a23302f7e79e3c Mon Sep 17 00:00:00 2001
   2 From: Carlos de Paula <me@carlosedp.com>
   3 Date: Tue, 18 Feb 2020 17:10:37 -0500
   4 Subject: [PATCH] arm64: dts: rockchip: Add txpbl node for RK3399/RK3328
   5
   6 Some rockchip SoCs like the RK3399 and RK3328 exhibit an issue
   7 where tx checksumming does not work with packets larger than 1498.
   8
   9 The default Programmable Buffer Length for TX in these GMAC's is
  10 not suitable for MTUs higher than 1498. The workaround is to disable
  11 TX offloading with 'ethtool -K eth0 tx off rx off' causing performance
  12 impacts as it disables hardware checksumming.
  13
  14 This patch sets snps,txpbl to 0x4 which is a safe number tested ok for
  15 the most popular MTU value of 1500.
  16
  17 For reference, see https://lkml.org/lkml/2019/4/1/1382.
  18
  19 Signed-off-by: Carlos de Paula <me@carlosedp.com>
  20 Link: https://lore.kernel.org/r/20200218221040.10955-1-me@carlosedp.com
  21 Signed-off-by: Heiko Stuebner <heiko@sntech.de>
  22 ---
  23  arch/arm64/boot/dts/rockchip/rk3328.dtsi | 2 ++
  24  arch/arm64/boot/dts/rockchip/rk3399.dtsi | 1 +
  25  2 files changed, 3 insertions(+)
  26
  27 --- a/arch/arm64/boot/dts/rockchip/rk3328.dtsi
  28 +++ b/arch/arm64/boot/dts/rockchip/rk3328.dtsi
  29 @@ -857,6 +857,7 @@
  30                 resets = <&cru SRST_GMAC2IO_A>;
  31                 reset-names = "stmmaceth";
  32                 rockchip,grf = <&grf>;
  33 +               snps,txpbl = <0x4>;
  34                 status = "disabled";
  35         };
  36
  37 @@ -878,6 +879,7 @@
  38                 reset-names = "stmmaceth", "mac-phy";
  39                 phy-mode = "rmii";
  40                 phy-handle = <&phy>;
  41 +               snps,txpbl = <0x4>;
  42                 status = "disabled";
  43
  44                 mdio {
  45 --- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
  46 +++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
  47 @@ -291,6 +291,7 @@
  48                 resets = <&cru SRST_A_GMAC>;
  49                 reset-names = "stmmaceth";
  50                 rockchip,grf = <&grf>;
  51 +               snps,txpbl = <0x4>;
  52                 status = "disabled";
  53         };
  54