On Wednesday, 10 July 2024 11:33:56 CEST Philipp Puschmann wrote:
> DMA names are required by of_dma_request_slave_channel function that is
> called during uart probe. So to enable DMA for uarts add the names as in
> the RK3568 TRM.

Setting it on channels without flow control apparently causes issues. See

https://lore.kernel.org/linux-rockchip/20240628120130.24076-1-didi.debian@cknow.org/

> Signed-off-by: Philipp Puschmann <p.puschmann@pironex.com>
> ---
>  arch/arm64/boot/dts/rockchip/rk356x.dtsi | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> b/arch/arm64/boot/dts/rockchip/rk356x.dtsi index d8543b5557ee..4ae40661ca6a
> 100644
> --- a/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> @@ -489,6 +489,7 @@ uart0: serial@fdd50000 {
>  		clocks = <&pmucru SCLK_UART0>, <&pmucru PCLK_UART0>;
>  		clock-names = "baudclk", "apb_pclk";
>  		dmas = <&dmac0 0>, <&dmac0 1>;
> +		dma-names = "tx", "rx";
>  		pinctrl-0 = <&uart0_xfer>;
>  		pinctrl-names = "default";
>  		reg-io-width = <4>;
> @@ -1389,6 +1390,7 @@ uart1: serial@fe650000 {
>  		clocks = <&cru SCLK_UART1>, <&cru PCLK_UART1>;
>  		clock-names = "baudclk", "apb_pclk";
>  		dmas = <&dmac0 2>, <&dmac0 3>;
> +		dma-names = "tx", "rx";
>  		pinctrl-0 = <&uart1m0_xfer>;
>  		pinctrl-names = "default";
>  		reg-io-width = <4>;
> ...