On Thu, Aug 28, 2025 at 06:22:40PM +0800, luyulin@xxxxxxxxxxxxxxxxxx wrote: > > Do you mean that ports-implemented should be removed from the dts, > and the corresponding register should be configured by the firmware > (which is U-Boot on the HiFive Premier P550 board)? Is this understanding correct? > If so, when the driver is removed, a reset will be triggered, > causing the configuration of this register to be lost, > which will result in an error when insmod the driver again. My 50 cents, if the ports implemented register gets reset from the reset_control_reset() in ahci_platform_assert_rsts(), then it seems like having ports-implemented in device tree is acceptable. There are a bunch of device trees that have this already: arch/arm/boot/dts/qcom/qcom-apq8064.dtsi: ports-implemented = <0x1>; arch/arm/boot/dts/qcom/qcom-ipq8064-v1.0.dtsi: ports-implemented = <0x1>; arch/arm/boot/dts/qcom/qcom-ipq8064-v2.0.dtsi: ports-implemented = <0x1>; arch/arm/boot/dts/samsung/exynos5250.dtsi: ports-implemented = <0x1>; arch/arm/boot/dts/socionext/uniphier-pro4.dtsi: ports-implemented = <1>; arch/arm/boot/dts/socionext/uniphier-pro4.dtsi: ports-implemented = <1>; arch/arm/boot/dts/socionext/uniphier-pxs2.dtsi: ports-implemented = <1>; arch/arm/boot/dts/st/stih407-family.dtsi: ports-implemented = <0x1>; arch/arm/boot/dts/st/stih407-family.dtsi: ports-implemented = <0x1>; arch/arm/boot/dts/ti/omap/dra7-l4.dtsi: ports-implemented = <0x1>; arch/arm/boot/dts/ti/omap/omap5-l4.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/mediatek/mt7622.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/rockchip/rk3568.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/rockchip/rk356x-base.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/rockchip/rk356x-base.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/rockchip/rk3576.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/rockchip/rk3576.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/rockchip/rk3588-base.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/rockchip/rk3588-base.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/rockchip/rk3588-extra.dtsi: ports-implemented = <0x1>; arch/arm64/boot/dts/socionext/uniphier-pxs3.dtsi: ports-implemented = <1>; arch/arm64/boot/dts/socionext/uniphier-pxs3.dtsi: ports-implemented = <1>; Sure, if the ports implemented register was sticky (kept its value after a reset), then I think Rob's suggestion would make sense. Kind regards, Niklas
