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From: "Heiko Stübner" <heiko@sntech.de>
To: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Ed Wildgoose <lists@wildgooses.com>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	Ed Wildgoose <lists@wildgooses.com>
Subject: Re: [PATCH 2/2] rockchip: dts: Enable UART DMA by adding default dma-names property
Date: Thu, 18 Sep 2025 18:22:12 +0200	[thread overview]
Message-ID: <3477683.usfYGdeWWP@diego> (raw)
In-Reply-To: <20250918093246.15623-3-lists@wildgooses.com>

Hi,

Am Donnerstag, 18. September 2025, 11:32:46 Mitteleuropäische Sommerzeit schrieb Ed Wildgoose:
> Kernel appears to need a dma-names set for DMA to actually enable. Set a
> default dma-names property for all UARTs defined in the board
> definition: rk3566-radxa-zero-3.dtsi
> 
> This is tested on a Radxa Zero 3W (which has 5x UARTs) and removes the
> warnings and enables DMA on this platform

the kernel does not _need_ the dmas and the uart will work just fine
without.

And as was pointed out in the previous version, the uarts have possible
stability issues, when connected to specific peripherals

So I'd prefer to not enable uart dmas "just for fun".

Heiko


> Signed-off-by: Ed Wildgoose <lists@wildgooses.com>
> ---
>  arch/arm64/boot/dts/rockchip/rk3566-radxa-zero-3.dtsi | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3566-radxa-zero-3.dtsi b/arch/arm64/boot/dts/rockchip/rk3566-radxa-zero-3.dtsi
> index e644bfc9c..fc26a4a52 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3566-radxa-zero-3.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3566-radxa-zero-3.dtsi
> @@ -488,21 +488,29 @@ &tsadc {
>  	status = "okay";
>  };
>  
> +&uart1 {
> +	dma-names = "tx", "rx";
> +};
> +
>  &uart2 {
> +	dma-names = "tx", "rx";
>  	status = "okay";
>  };
>  
>  &uart4{
> +	dma-names = "tx", "rx";
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&uart4m1_xfer>;
>  };
>  
>  &uart5 {
> +	dma-names = "tx", "rx";
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&uart5m1_xfer>;
>  };
>  
>  &uart9 {
> +	dma-names = "tx", "rx";
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&uart9m1_xfer>;
>  };
> 





  reply	other threads:[~2025-09-18 16:22 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-17 11:49 [PATCH 0/2] arm64: dts: rockchip: fix dma and pinctrl defs Ed Wildgoose
2025-09-17 11:49 ` [PATCH 1/2] arm64: dts: rockchip: correct uart mux for Radxa ZERO 3 Ed Wildgoose
2025-09-18  4:53   ` FUKAUMI Naoki
2025-09-18 15:23     ` Ed W
2025-09-18 16:18       ` [PATCH 1/2] arm64: dts: rockchip: correct uart mux for Radxa ZERO3 Heiko Stübner
2025-09-18 23:57         ` FUKAUMI Naoki
2025-09-19  9:28           ` Ed W
2025-09-19 10:17           ` Heiko Stübner
2025-09-19 10:21             ` FUKAUMI Naoki
2025-09-19  0:13       ` [PATCH 1/2] arm64: dts: rockchip: correct uart mux for Radxa ZERO 3 FUKAUMI Naoki
2025-09-20  8:14   ` Jonas Karlman
2025-09-17 11:49 ` [PATCH 2/2] rockchip: dts: Enable UART DMA by adding default dma-names property Ed Wildgoose
2025-09-17 12:22   ` Dragan Simic
2025-09-17 14:25     ` Heiko Stübner
2025-09-18  9:32 ` [PATCH 0/2] arm64: dts: rockchip: fix dma and pinctrl defs v2 Ed Wildgoose
2025-09-18  9:32   ` [PATCH 1/2] arm64: dts: rockchip: correct uart mux for Radxa ZERO 3 Ed Wildgoose
2025-09-18  9:32   ` [PATCH 2/2] rockchip: dts: Enable UART DMA by adding default dma-names property Ed Wildgoose
2025-09-18 16:22     ` Heiko Stübner [this message]
2025-09-18 16:20   ` [PATCH 0/2] arm64: dts: rockchip: fix dma and pinctrl defs v2 Heiko Stübner

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