Implement device wipe using the hardware button on Green (#3523)

* Improve LED naming in U-Boot DTS

Port Stefan's patch from Linux patchset to U-Boot.

* Implement device wipe using the hardware button on Green

Unlike Yellow, Green doesn't have a way to easily wipe the device, e.g. if the
user forgets the password - in that case the only option is to use a microSD
card and reflash the system. Fortunately, Green has a hardware button wired to
the PMIC chip which exposes the button state in one of the registers. Read this
value in U-Boot and decide if cmdline flag for device wipe should be set - same
as we do on Yellow.

Also enable LED driver and command in U-Boot. In the current implementation, if
the button is held for ~5 seconds when plugging in the device (this time
includes DDR training, SPL, etc.), the yellow LED turns solid to indicate wipe
is about the start. When the Linux kernel starts, the kernel LED driver takes
over and starts blinking in heartbeat pattern. Because it takes a while to load
the kernel, the LED stays solid for 2-3 seconds, which should be enough to
recognize it was acknowledged.

* Wait for button to be released before wiping

buildroot-external/board/nabucasa/green/patches/uboot/0010-arch-arm64-dts-green-Improve-LED-representation.patch

@@ -0,0 +1,52 @@
+From d3fb1ec2364b20025d71e2263514a71208cfb61e Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Jan=20=C4=8Cerm=C3=A1k?= <[email protected]>
+Date: Tue, 13 Aug 2024 17:51:29 +0200
+Subject: [PATCH] arch: arm64: dts: green: Improve LED representation
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Fix color and use labels/node names according to the LEDs functionality.
+
+Signed-off-by: Jan Čermák <[email protected]>
+Co-authored-by: Stefan Agner <[email protected]>
+---
+ arch/arm/dts/rk3566-ha-green.dts | 11 +++++++----
+ 1 file changed, 7 insertions(+), 4 deletions(-)
+
+diff --git a/arch/arm/dts/rk3566-ha-green.dts b/arch/arm/dts/rk3566-ha-green.dts
+index 68d836911e..c3adc59904 100644
+--- a/arch/arm/dts/rk3566-ha-green.dts
++++ b/arch/arm/dts/rk3566-ha-green.dts
+@@ -48,16 +48,18 @@
+ 	leds {
+ 		compatible = "gpio-leds";
+
+-		led_power: led-0 {
++		led_power: led-power {
++			label = "power";
+ 			gpios = <&gpio0 RK_PB6 GPIO_ACTIVE_HIGH>;
+ 			function = LED_FUNCTION_POWER;
+-			color = <LED_COLOR_ID_RED>;
++			color = <LED_COLOR_ID_WHITE>;
+ 			default-state = "keep";
+ 			linux,default-trigger = "default-on";
+ 			pinctrl-names = "default";
+ 			pinctrl-0 = <&led_power_pin>;
+ 		};
+-		led_act: led-1 {
++		led_act: led-activity {
++			label = "activity";
+ 			gpios = <&gpio0 RK_PB7 GPIO_ACTIVE_HIGH>;
+ 			function = LED_FUNCTION_ACTIVITY;
+ 			color = <LED_COLOR_ID_GREEN>;
+@@ -65,7 +67,8 @@
+ 			pinctrl-names = "default";
+ 			pinctrl-0 = <&led_act_pin>;
+ 		};
+-		led_user: led-2 {
++		led_user: led-user {
++			label = "user";
+ 			gpios = <&gpio0 RK_PC5 GPIO_ACTIVE_HIGH>;
+ 			function = LED_FUNCTION_HEARTBEAT;
+ 			color = <LED_COLOR_ID_YELLOW>;

buildroot-external/board/nabucasa/green/uboot-boot.ush

@@ -27,6 +27,36 @@ test -n "${MACHINE_ID}" || setenv BOOT_CONDITION "systemd.condition-first-boot=t
 # HassOS bootargs
 setenv bootargs_hassos "zram.enabled=1 zram.num_devices=3 rootwait systemd.machine_id=${MACHINE_ID} fsck.repair=yes ${BOOT_CONDITION}"
 
+i2c dev 0
+setenv check_btn_pressed ' \
+    i2c read 0x20 0xf0.1 1 ${loadaddr}; \
+    setexpr PWRON_STS *${loadaddr} \\\& 0x80; \
+    test ${PWRON_STS} -eq 0x0;'
+
+# Check if button is held for device wipe
+setenv counter 0
+while test ${counter} -lt 2; do
+  if run check_btn_pressed; then
+    echo "Reset button pressed for ${counter} seconds"
+    setexpr counter ${counter} + 1
+
+    if test ${counter} -eq 2; then
+      led user on
+      echo "Waiting for button to be released"
+      while run check_btn_pressed; do
+        sleep 0.5
+      done
+      echo "Proceeding with device wipe"
+      setenv bootargs_hassos "${bootargs_hassos} haos.wipe=1"
+    else
+      sleep 1
+    fi
+  else
+    # U-Boot has no break statement :')
+    setenv counter 2
+  fi
+done
+
 # HassOS system A/B
 setenv bootargs_a "root=PARTUUID=8d3d53e3-6d49-4c38-8349-aff6859e82fd ro"
 setenv bootargs_b "root=PARTUUID=a3ec664e-32ce-4665-95ea-7ae90ce9aa20 ro"

buildroot-external/board/nabucasa/green/uboot.config

@@ -0,0 +1,3 @@
+CONFIG_LED=y
+CONFIG_LED_GPIO=y
+CONFIG_CMD_LED=y

buildroot-external/configs/green_defconfig

@@ -143,7 +143,7 @@ BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2024.01"
 BR2_TARGET_UBOOT_BOARD_DEFCONFIG="green"
-BR2_TARGET_UBOOT_CONFIG_FRAGMENT_FILES="$(BR2_EXTERNAL_HASSOS_PATH)/bootloader/uboot.config"
+BR2_TARGET_UBOOT_CONFIG_FRAGMENT_FILES="$(BR2_EXTERNAL_HASSOS_PATH)/bootloader/uboot.config $(BR2_EXTERNAL_HASSOS_PATH)/board/nabucasa/green/uboot.config"
 BR2_TARGET_UBOOT_NEEDS_PYLIBFDT=y
 BR2_TARGET_UBOOT_NEEDS_PYELFTOOLS=y
 BR2_TARGET_UBOOT_NEEDS_ATF_BL31=y