[PATCH] rock64: dts: fix gmac2io stability issues

[PATCH] rock64: dts: fix gmac2io stability issues

[Kamil Trzciński]

This commit enables thresh dma mode as this forces to disable checksuming,
and chooses delay values which make the interface stable.

These changes are needed, because ROCK64 is faced with two problems:
1. tx checksuming does not work with packets larger than 1498,
2. the default delays for tx/rx are not stable when using 1Gbps connection.

Delays were found out with:
https://github.com/ayufan-rock64/linux-build/tree/master/recipes/gmac-delays-test

Change-Id: Ie894df4b52122988da683c02e3a05d635a5c7b84
Signed-off-by: Kamil Trzci?ski <ayufan@ayufan.eu>
---
 arch/arm64/boot/dts/rockchip/rk3328-rock64.dts | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts b/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
index 5602ec01fed9..bcc0bb35d840 100644
--- a/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
@@ -132,8 +132,6 @@
 	assigned-clocks = <&cru SCLK_MAC2IO>, <&cru SCLK_MAC2IO_EXT>;
 	assigned-clock-parents = <&gmac_clkin>, <&gmac_clkin>;
 	clock_in_out = "input";
-	/* shows instability at 1GBit right now */
-	max-speed = <100>;
 	phy-supply = <&vcc_io>;
 	phy-mode = "rgmii";
 	pinctrl-names = "default";
@@ -141,8 +139,9 @@
 	snps,reset-gpio = <&gpio1 RK_PC2 GPIO_ACTIVE_LOW>;
 	snps,reset-active-low;
 	snps,reset-delays-us = <0 10000 50000>;
-	tx_delay = <0x26>;
-	rx_delay = <0x11>;
+	snps,force_thresh_dma_mode;
+	tx_delay = <0x24>;
+	rx_delay = <0x18>;
 	status = "okay";
 };
 
-- 
2.14.1

[PATCH] rock64: dts: fix gmac2io stability issues

[Heiko Stübner]

Hi Kamil,

Thanks for figuring out the source of the gmac instability :-) .

I've applied the patch as fix for 4.16 but corrected some small issues while 
doing so:
- The subject should be something like
	"arm64: dts: rockchip: fix rock64 gmac2io stability issues"
  The prefixes to use vary per subsystem, so it's best to use git log to
  look at previous commits

Am Montag, 22. Januar 2018, 18:46:22 CET schrieb Kamil Trzci?ski:
> This commit enables thresh dma mode as this forces to disable checksuming,
> and chooses delay values which make the interface stable.
> 
> These changes are needed, because ROCK64 is faced with two problems:
> 1. tx checksuming does not work with packets larger than 1498,
> 2. the default delays for tx/rx are not stable when using 1Gbps connection.
> 
> Delays were found out with:
> https://github.com/ayufan-rock64/linux-build/tree/master/recipes/gmac-delays
> -test
> 
> Change-Id: Ie894df4b52122988da683c02e3a05d635a5c7b84

That is some gerrit thingy which should not be part when sending patches 
upstream.

> Signed-off-by: Kamil Trzci?ski <ayufan@ayufan.eu>
> ---
>  arch/arm64/boot/dts/rockchip/rk3328-rock64.dts | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
> b/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts index
> 5602ec01fed9..bcc0bb35d840 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
> @@ -132,8 +132,6 @@
>  	assigned-clocks = <&cru SCLK_MAC2IO>, <&cru SCLK_MAC2IO_EXT>;
>  	assigned-clock-parents = <&gmac_clkin>, <&gmac_clkin>;
>  	clock_in_out = "input";
> -	/* shows instability at 1GBit right now */
> -	max-speed = <100>;
>  	phy-supply = <&vcc_io>;
>  	phy-mode = "rgmii";
>  	pinctrl-names = "default";
> @@ -141,8 +139,9 @@
>  	snps,reset-gpio = <&gpio1 RK_PC2 GPIO_ACTIVE_LOW>;
>  	snps,reset-active-low;
>  	snps,reset-delays-us = <0 10000 50000>;
> -	tx_delay = <0x26>;
> -	rx_delay = <0x11>;
> +	snps,force_thresh_dma_mode;

With the exception of compatible, reg, interrupts and status, I try to keep
other properties alphabetically sorted in Rockchip dts, so I've moved the
snps,force_thres_dma_mode up between pinctrl-0 and snps-reset-gpio.


Heiko