cpu/esp_common: Add Kconfig symbols

cpu/esp_common/Kconfig

@@ -0,0 +1,48 @@
+# Copyright (c) 2020 HAW Hamburg
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+
+config CPU_ARCH_XTENSA
+    bool
+    select HAS_ARCH_32BIT
+    select HAS_ARCH_ESP
+
+config CPU_COMMON_ESP
+    bool
+    select HAS_CPP
+    select HAS_ESP_NOW
+    select HAS_ESP_SPIFFS
+    select HAS_ESP_WIFI
+    select HAS_PERIPH_CPUID
+    select HAS_PERIPH_HWRNG
+    select HAS_PERIPH_PM
+    select HAS_PERIPH_TIMER
+    select HAS_SSP
+
+## Declaration of specific features
+config HAS_ESP_SPIFFS
+    bool
+    help
+        Indicates that a Serial Peripheral Interface Flash File System can be
+        used.
+
+config HAS_ESP_WIFI
+    bool
+    help
+        Indicates that an ESP WiFi radio is present.
+
+config HAS_ESP_NOW
+    bool
+    help
+        Indicates that an ESP NOW-compatible radio is present.
+
+config HAS_ARCH_ESP
+    bool
+    help
+        Indicates that an 'ESP' architecture is being used.
+
+## Common CPU symbols
+config CPU_ARCH
+    default "xtensa" if CPU_ARCH_XTENSA

cpu/esp_common/Makefile.features

@@ -1,3 +1,5 @@
+CPU_ARCH = xtensa
+
 # MCU defined features that are provided independent on board definitions
 
 FEATURES_PROVIDED += arch_32bit