Re: [PATCH 4/5] arm64: dts: rockchip: add the PCIe power domain to the RK3588 PCIe SMMU

[Sebastian Reichel <sebastian.reichel@collabora.com>]

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Hi,

On Tue, Nov 10, 2026 at 07:11:51AM +0000, Arun Iyengar via B4 Relay wrote:
> From: Arun Iyengar <aiyengar1990@gmail.com>
> 
> The MMU-600 for the PCIe controllers (mmu600_pcie) is enabled for every
> RK3588 board, but its node does not describe that it lives in
> RK3588_PD_PCIE. It only works today because TF-A leaves the domain on at
> boot and, on most boards, an enabled PCIe controller holds it on later.
> 
> On a board that disables all PCIe controllers using that domain (the
> Orange Pi 5 with its M.2 slot in SATA mode is one), genpd powers
> PD_PCIE off as unused after boot while arm-smmu-v3 is still bound. Then
> at reboot arm_smmu_device_shutdown() writes CR0 and polls CR0ACK on the
> unpowered block, which stalls the bus: the kernel never reaches
> "reboot: Restarting system" and the board only comes back once the
> watchdog fires.
> 
> Describe the power domain, so genpd keeps it on for as long as the SMMU
> is bound.
> 
> Fixes: da92d3dfc871 ("arm64: dts: rockchip: enable the mmu600_pcie IOMMU on the rk3588 SoC")
> Signed-off-by: Arun Iyengar <aiyengar1990@gmail.com>
> ---
>  arch/arm64/boot/dts/rockchip/rk3588-base.dtsi | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3588-base.dtsi b/arch/arm64/boot/dts/rockchip/rk3588-base.dtsi
> index aa69fd3793fd..bcd342c025c9 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3588-base.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3588-base.dtsi
> @@ -560,6 +560,7 @@ mmu600_pcie: iommu@fc900000 {
>  			     <GIC_SPI 367 IRQ_TYPE_EDGE_RISING 0>;
>  		interrupt-names = "eventq", "gerror", "priq", "cmdq-sync";
>  		#iommu-cells = <1>;
> +		power-domains = <&power RK3588_PD_PCIE>;

The TRM says the power domain of MMU600_PCIE is PD_PHP, not PD_PCIE.
See Table 7-1 RK3588 Voltage Domain and Power Domain Summary around
page 1096 (depending on specific TRM version).

Note, that PD_PCIE is a child of PD_PHP, so it makes sense that
PD_PCIE also works.

Greetings,

-- Sebastian

>  	};
>  
>  	mmu600_php: iommu@fcb00000 {
> 
> -- 
> 2.55.0
> 
> 
> 

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