From 2b583ab8a74a6bd41f1c9629b3b66ba561d6fceb Mon Sep 17 00:00:00 2001
From: David Bauer <mail@david-bauer.net>
Date: Tue, 25 Jan 2022 21:46:54 +0100
Subject: [PATCH] rockchip: disable UHS modes for NanoPi R4S
The NanoPi R4S leaves the SD card in 1.8V signalling when rebooting
while U-Boot requires the card to be in 3.3V mode.
Remove UHS support from the SD controller so the card remains in 3.3V
mode. This reduces transfer speeds but ensures a reboot whether from
userspace or following a kernel panic is always working.
Signed-off-by: David Bauer <mail@david-bauer.net>
---
.../105-nanopi-r4s-sd-signalling.patch | 26 +++++++++++++++++++
1 file changed, 26 insertions(+)
create mode 100644 target/linux/rockchip/patches-5.10/105-nanopi-r4s-sd-signalling.patch
diff --git a/target/linux/rockchip/patches-5.10/105-nanopi-r4s-sd-signalling.patch b/target/linux/rockchip/patches-5.10/105-nanopi-r4s-sd-signalling.patch
new file mode 100644
index 00000000000..a04c14b70a7
--- /dev/null
+++ b/target/linux/rockchip/patches-5.10/105-nanopi-r4s-sd-signalling.patch
@@ -0,0 +1,26 @@
+From: David Bauer <mail@david-bauer.net>
+Subject: arm64: dts: rockchip: disable UHS modes for NanoPi R4S
+
+The NanoPi R4S leaves the SD card in 1.8V signalling when rebooting
+while U-Boot requires the card to be in 3.3V mode.
+
+Remove UHS support from the SD controller so the card remains in 3.3V
+mode. This reduces transfer speeds but ensures a reboot whether from
+userspace or following a kernel panic is always working.
+
+Signed-off-by: David Bauer <mail@david-bauer.net>
+
+--- a/arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts
++++ b/arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts
+@@ -121,6 +121,11 @@
+ status = "disabled";
+ };
+
++&sdmmc {
++ /delete-property/ sd-uhs-sdr104;
++ cap-sd-highspeed;
++};
++
+ &u2phy0_host {
+ phy-supply = <&vdd_5v>;
+ };
--
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