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

[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.)

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>;
 		};
-- 
2.41.0