[nrfconnect] Added calculating unique id length based on kconfig (#27032

)

Currently the unique id length is fixed to 16 B and in nrfconnect
platform we allow to set unique id value through kconfig, which may
lead to a problem that length of selected data will not match the
unique id length hardcoded to 16 B.

Added calculating the unique id length based on Kconfig
or assigning the max value assumed for the factory data storage.

config/nrfconnect/chip-module/Kconfig

@@ -127,6 +127,13 @@ config CHIP_FACTORY_DATA_VERSION
 	  this value in the factory data provider implementation to verify that the
 	  factory data saved in the flash memory has the expected version.
 
+config CHIP_FACTORY_DATA_ROTATING_DEVICE_UID_MAX_LEN
+	int "Maximum length of rotating device ID unique ID in bytes"
+	default 16
+	depends on CHIP_FACTORY_DATA
+	help
+	  Maximum acceptable length of rotating device ID unique ID in bytes.
+
 if CHIP_FACTORY_DATA_BUILD
 
 # Factory data definitions

src/platform/nrfconnect/CHIPDevicePlatformConfig.h

@@ -249,3 +249,15 @@
 #ifdef CONFIG_CHIP_EXTENDED_DISCOVERY
 #define CHIP_DEVICE_CONFIG_ENABLE_EXTENDED_DISCOVERY 1
 #endif // CONFIG_CHIP_EXTENDED_DISCOVERY
+
+#ifndef CHIP_DEVICE_CONFIG_ROTATING_DEVICE_ID_UNIQUE_ID_LENGTH
+#if CONFIG_CHIP_FACTORY_DATA
+// UID will be copied from the externally programmed factory data, so we don't know the actual length and we need to assume some max
+// boundary.
+#define CHIP_DEVICE_CONFIG_ROTATING_DEVICE_ID_UNIQUE_ID_LENGTH CONFIG_CHIP_FACTORY_DATA_ROTATING_DEVICE_UID_MAX_LEN
+#else
+// UID will be copied from hex encoded Kconfig option, so we may calculate its length in bytes by subtracting null terminator and
+// dividing size by 2.
+#define CHIP_DEVICE_CONFIG_ROTATING_DEVICE_ID_UNIQUE_ID_LENGTH ((sizeof(CONFIG_CHIP_DEVICE_ROTATING_DEVICE_UID) - 1) / 2)
+#endif // CONFIG_CHIP_FACTORY_DATA
+#endif // CHIP_DEVICE_CONFIG_ROTATING_DEVICE_ID_UNIQUE_ID_LENGTH

src/platform/nrfconnect/FactoryDataProvider.cpp

@@ -323,6 +323,8 @@ CHIP_ERROR FactoryDataProvider<FlashFactoryData>::GetRotatingDeviceIdUniqueId(Mu
 
     memcpy(uniqueIdSpan.data(), mFactoryData.rd_uid.data, mFactoryData.rd_uid.len);
 
+    uniqueIdSpan.reduce_size(mFactoryData.rd_uid.len);
+
     return CHIP_NO_ERROR;
 }