Re: [PATCH v2] arm64: dts: rockchip: Add PCIe pinctrls to Turing RK1

[Heiko Stübner]

Hi Sam,

Am Freitag, 8. Dezember 2023, 07:25:10 CET schrieb Sam Edwards:
> The RK3588 PCIe 3.0 controller seems to have unpredictable behavior when
> no CLKREQ/PERST/WAKE pins are configured in the pinmux. In particular, it
> will sometimes (varying between specific RK3588 chips, not over time) shut
> off the DBI block, and reads to this range will instead stall
> indefinitely.
> 
> When this happens, it will prevent Linux from booting altogether. The
> PCIe driver will stall the CPU core once it attempts to read the version
> information from the DBI range.
> 
> Fix this boot hang by adding the correct pinctrl configuration to the
> PCIe 3.0 device node, which is the proper thing to do anyway. While
> we're at it, also add the necessary configuration to the PCIe 2.0 node,
> which may or may not fix the equivalent problem over there -- but is the
> proper thing to do anyway. :)
> 
> Fixes: 2806a69f3fef6 ("arm64: dts: rockchip: Add Turing RK1 SoM support")
> Signed-off-by: Sam Edwards <CFSworks@xxxxxxxxx>
> ---
> 
> Hi list,
> 
> Compared to v1, v2 removes the `reset-gpios` properties as well -- this should
> give control of the PCIe resets exclusively to the PCIe cores. (And even if the
> `reset-gpios` props had no effect in v1, it'd be confusing to have them there.)

Hmm, I'd think this could result in differing behaviour.

I.e. I tried the same on a different board with a nvme drive on the pci30x4
controller. But moving the reset from the gpio-way to "just" setting the
perstn pinctrl, simply hung the controller when probing the device.

So I guess I'd think the best way would be to split the pinctrl up into the
3 separate functions (clkreqn, perstn, waken) so that boards can include
them individually.

Nobody is using the controller pinctrl entries so far anyway :-) .


Heiko


> Note that it is OK for the pcie2x1l1 node to refer to pcie30x1m1_pins. The
> pcie2x1l1 device is *in fact* a PCIe 3.0 controller, and the pcie30x1m1_pins
> pinmux setting is so-named to reflect this. The pcie2x1l1 node is so-named
> because Linux does not (currently) support routing it to a PCIe 3.0 PHY; so in
> practice it is effectively a PCIe 2.0 controller, for the time being.
> 
> Cheers and thank you for your time,
> Sam
> 
> ---
>  .../boot/dts/rockchip/rk3588-turing-rk1.dtsi     | 16 ++--------------
>  1 file changed, 2 insertions(+), 14 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3588-turing-rk1.dtsi b/arch/arm64/boot/dts/rockchip/rk3588-turing-rk1.dtsi
> index 9570b34aca2e..875446fdb67e 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3588-turing-rk1.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3588-turing-rk1.dtsi
> @@ -214,8 +214,7 @@ rgmii_phy: ethernet-phy@1 {
>  &pcie2x1l1 {
>  	linux,pci-domain = <1>;
>  	pinctrl-names = "default";
> -	pinctrl-0 = <&pcie2_reset>;
> -	reset-gpios = <&gpio4 RK_PA2 GPIO_ACTIVE_HIGH>;
> +	pinctrl-0 = <&pcie30x1m1_pins>;
>  	status = "okay";
>  };
>  
> @@ -226,8 +225,7 @@ &pcie30phy {
>  &pcie3x4 {
>  	linux,pci-domain = <0>;
>  	pinctrl-names = "default";
> -	pinctrl-0 = <&pcie3_reset>;
> -	reset-gpios = <&gpio4 RK_PB6 GPIO_ACTIVE_HIGH>;
> +	pinctrl-0 = <&pcie30x4m1_pins>;
>  	vpcie3v3-supply = <&vcc3v3_pcie30>;
>  	status = "okay";
>  };
> @@ -245,17 +243,7 @@ hym8563_int: hym8563-int {
>  		};
>  	};
>  
> -	pcie2 {
> -		pcie2_reset: pcie2-reset {
> -			rockchip,pins = <4 RK_PA2 RK_FUNC_GPIO &pcfg_pull_none>;
> -		};
> -	};
> -
>  	pcie3 {
> -		pcie3_reset: pcie3-reset {
> -			rockchip,pins = <4 RK_PB6 RK_FUNC_GPIO &pcfg_pull_none>;
> -		};
> -
>  		vcc3v3_pcie30_en: pcie3-reg {
>  			rockchip,pins = <2 RK_PC5 RK_FUNC_GPIO &pcfg_pull_none>;
>  		};
>