net: openthread: implement otPlatResetToBootloader

This commit implements `otPlatResetToBootloader` in two ways:

- trigger reset to bootloader using boot mode retention API
- trigger reset to bootloader by triggering GPIO pin (applicable
for nRF52840 Dongle)

Signed-off-by: Maciej Baczmanski <maciej.baczmanski@nordicsemi.no>

dts/bindings/options/openthread,config.yaml

@@ -10,6 +10,7 @@ description: |
       compatible = "openthread,config";
       diag-gpios = <&gpio0 0  GPIO_ACTIVE_HIGH>,
                    <&gpio1 0  GPIO_ACTIVE_LOW>;
+      bootloader-gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
     };
   };
 
@@ -21,3 +22,9 @@ properties:
     description: |
       This enables access to diagnostic GPIO pins. Each field consists of
       GPIO pin's configuration: controller's phandle, pin number and configuration flags.
+
+  bootloader-gpios:
+    type: phandle-array
+    description: |
+      This enables resetting to bootloader by triggering given GPIO pin. Property represents
+      chosen GPIO pin's configuration: controller's phandle, pin number and configuration flags.

modules/openthread/CMakeLists.txt

@@ -99,6 +99,7 @@ kconfig_to_ot_option(CONFIG_OPENTHREAD_NETDATA_PUBLISHER OT_NETDATA_PUBLISHER "E
 kconfig_to_ot_option(CONFIG_OPENTHREAD_OPERATIONAL_DATASET_AUTO_INIT OT_OPERATIONAL_DATASET_AUTO_INIT "Enable operational dataset auto init")
 kconfig_to_ot_option(CONFIG_OPENTHREAD_OTNS OT_OTNS "Enable OTNS support")
 kconfig_to_ot_option(CONFIG_OPENTHREAD_PING_SENDER OT_PING_SENDER "Enable ping sender support")
+kconfig_to_ot_option(CONFIG_OPENTHREAD_PLATFORM_BOOTLOADER_MODE OT_PLATFORM_BOOTLOADER_MODE "Enable platform bootloader mode support")
 kconfig_to_ot_option(CONFIG_OPENTHREAD_PLATFORM_KEY_REF OT_PLATFORM_KEY_REF "Enable platform key reference support")
 kconfig_to_ot_option(CONFIG_OPENTHREAD_PLATFORM_NETIF OT_PLATFORM_NETIF "Enable platform netif support")
 kconfig_to_ot_option(CONFIG_OPENTHREAD_PLATFORM_UDP OT_PLATFORM_UDP "Enable platform UDP support")

modules/openthread/Kconfig.features

@@ -17,7 +17,7 @@ config OPENTHREAD_THREAD_VERSION_1_3
 	bool "Version 1.3"
 config OPENTHREAD_THREAD_VERSION_1_3_1
 	bool "Version 1.3.1"
-endchoice
+endchoice # OPENTHREAD_STACK_VERSION
 
 config OPENTHREAD_THREAD_VERSION
 	string
@@ -255,6 +255,25 @@ config OPENTHREAD_PLATFORM_KEY_REF
 	  Enable usage of cryptographic key references instead of literal keys.
 	  This requires a crypto backend library that supports key references.
 
+choice OPENTHREAD_PLATFORM_BOOTLOADER_MODE_CHOICE
+	prompt "Platform bootloader mode configuration"
+	optional
+
+config OPENTHREAD_PLATFORM_BOOTLOADER_MODE_RETENTION
+	bool "Bootloader mode support with boot mode retention API"
+	depends on RETENTION_BOOT_MODE && REBOOT
+	select OPENTHREAD_PLATFORM_BOOTLOADER_MODE
+
+config OPENTHREAD_PLATFORM_BOOTLOADER_MODE_GPIO
+	bool "Bootloader mode support with GPIO pin trigger"
+	select OPENTHREAD_PLATFORM_BOOTLOADER_MODE
+endchoice # OPENTHREAD_PLATFORM_BOOTLOADER_MODE
+
+config OPENTHREAD_PLATFORM_BOOTLOADER_MODE
+	bool
+	help
+	  Platform bootloader mode support
+
 config OPENTHREAD_PLATFORM_NETIF
 	bool "Platform netif support"
 
@@ -276,7 +295,7 @@ config OPENTHREAD_POWER_SUPPLY_EXTERNAL_STABLE
 
 config OPENTHREAD_POWER_SUPPLY_EXTERNAL_UNSTABLE
 	bool "OT_POWER_SUPPLY_EXTERNAL_UNSTABLE"
-endchoice
+endchoice # OPENTHREAD_POWER_SUPPLY_CHOICE
 
 config OPENTHREAD_POWER_SUPPLY
 	string

modules/openthread/platform/misc.c

@@ -9,6 +9,24 @@
 #include <openthread/instance.h>
 #include <openthread/platform/misc.h>
 
+#if defined(CONFIG_OPENTHREAD_PLATFORM_BOOTLOADER_MODE_RETENTION)
+
+#include <zephyr/retention/bootmode.h>
+
+#elif defined(CONFIG_OPENTHREAD_PLATFORM_BOOTLOADER_MODE_GPIO)
+
+BUILD_ASSERT(DT_HAS_COMPAT_STATUS_OKAY(openthread_config),
+	"`openthread,config` compatible node not found");
+BUILD_ASSERT(DT_NODE_HAS_PROP(DT_COMPAT_GET_ANY_STATUS_OKAY(openthread_config), bootloader_gpios),
+	"`bootloader-gpios` property missing from `openthread,config` compatible node");
+
+#include <zephyr/drivers/gpio.h>
+
+static const struct gpio_dt_spec bootloader_gpio =
+	GPIO_DT_SPEC_GET(DT_COMPAT_GET_ANY_STATUS_OKAY(openthread_config),
+			 bootloader_gpios);
+#endif
+
 #include "platform-zephyr.h"
 
 void otPlatReset(otInstance *aInstance)
@@ -19,6 +37,54 @@ void otPlatReset(otInstance *aInstance)
 	sys_reboot(SYS_REBOOT_WARM);
 }
 
+#if defined(CONFIG_OPENTHREAD_PLATFORM_BOOTLOADER_MODE)
+otError otPlatResetToBootloader(otInstance *aInstance)
+{
+	OT_UNUSED_VARIABLE(aInstance);
+
+#if defined(CONFIG_OPENTHREAD_PLATFORM_BOOTLOADER_MODE_RETENTION)
+	if (bootmode_set(BOOT_MODE_TYPE_BOOTLOADER)) {
+		return OT_ERROR_NOT_CAPABLE;
+	}
+	sys_reboot(SYS_REBOOT_WARM);
+
+#elif defined(CONFIG_OPENTHREAD_PLATFORM_BOOTLOADER_MODE_GPIO)
+	/*
+	 * To enable resetting to bootloader by triggering gpio pin,
+	 * select `CONFIG_OPENTHREAD_PLATFORM_BOOTLOADER_MODE_GPIO=y`,
+	 * and in Devicetree create `openthread` node in `/options/` path with
+	 * `compatible = "openthread,config"` property and `bootloader-gpios` property,
+	 * which should represent GPIO pin's configuration,
+	 * containing controller phandle, pin number and pin flags. e.g:
+	 *
+	 * options {
+	 *	openthread {
+	 *		compatible = "openthread,config";
+	 *		bootloader-gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
+	 *	};
+	 * };
+	 *
+	 * Note: in below implementation, chosen GPIO pin is configured as output
+	 * and initialized to active state (logical value ‘1’).
+	 * Configuring pin flags in `bootloader-gpios` allows to choose
+	 * if pin should be active in high or in low state.
+	 */
+
+	if (!gpio_is_ready_dt(&bootloader_gpio)) {
+		return OT_ERROR_NOT_CAPABLE;
+	}
+	gpio_pin_configure_dt(&bootloader_gpio, GPIO_OUTPUT_ACTIVE);
+
+#endif
+
+	/*
+	 * Return OT_ERROR_NOT_CAPABLE if resetting has been unsuccessful (invalid configuration or
+	 * triggering reset had no effect)
+	 */
+	return OT_ERROR_NOT_CAPABLE;
+}
+#endif /* defined(CONFIG_OPENTHREAD_PLATFORM_BOOTLOADER_MODE) */
+
 otPlatResetReason otPlatGetResetReason(otInstance *aInstance)
 {
 	ARG_UNUSED(aInstance);