soc: esp32s2: add initial soc support files for esp32s2

by adding specific soc files for esp32s2 bring-up, such as:
- linker script
- soc initialization code
- initial device tree source files
- esp32s2 saola board support.

Signed-off-by: Glauber Maroto Ferreira <glauber.ferreira@espressif.com>

CODEOWNERS

@@ -400,6 +400,7 @@
 /dts/x86/                                 @jhedberg
 /dts/xtensa/xtensa.dtsi                   @ydamigos
 /dts/xtensa/intel/                        @dcpleung
+/dts/xtensa/espressif/                    @glaubermaroto
 /dts/sparc/                               @martin-aberg
 /dts/bindings/                            @galak
 /dts/bindings/can/                        @alexanderwachter

Kconfig.zephyr

@@ -568,7 +568,7 @@ endif # BOOTLOADER_MCUBOOT
 
 config BOOTLOADER_ESP_IDF
 	bool "ESP-IDF bootloader support"
-	depends on SOC_ESP32
+	depends on SOC_ESP32 || SOC_ESP32S2
 	help
 	  This option will trigger the compilation of the ESP-IDF bootloader
 	  inside the build folder.

boards/xtensa/esp32s2_saola/CMakeLists.txt

@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: Apache-2.0
+
+if(CONFIG_BOOTLOADER_ESP_IDF)
+  include(ExternalProject)
+
+  ## we use hello-world project, but I think any can be used.
+  set(espidf_components_dir   ${ESP_IDF_PATH}/components)
+  set(espidf_prefix    ${CMAKE_BINARY_DIR}/esp-idf)
+  set(espidf_build_dir ${espidf_prefix}/build)
+
+  ExternalProject_Add(
+    EspIdfBootloader
+    PREFIX ${espidf_prefix}
+    SOURCE_DIR ${espidf_components_dir}/bootloader/subproject
+    BINARY_DIR ${espidf_build_dir}/bootloader
+    CONFIGURE_COMMAND
+    ${CMAKE_COMMAND} -G${CMAKE_GENERATOR}
+    -S ${espidf_components_dir}/bootloader/subproject
+    -B ${espidf_build_dir}/bootloader -DSDKCONFIG=${espidf_build_dir}/sdkconfig
+    -DIDF_PATH=${ESP_IDF_PATH} -DIDF_TARGET=${CONFIG_SOC}
+    -DPYTHON_DEPS_CHECKED=1
+    -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
+    -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
+    -DCMAKE_ASM_COMPILER=${CMAKE_ASM_COMPILER}
+    -DCMAKE_SYSTEM_NAME=${CMAKE_SYSTEM_NAME}
+    BUILD_COMMAND
+    ${CMAKE_COMMAND} --build .
+    INSTALL_COMMAND ""      # This particular build system has no install command
+    )
+
+  ExternalProject_Add(
+    EspPartitionTable
+    SOURCE_DIR ${espidf_components_dir}/partition_table
+    BINARY_DIR ${espidf_build_dir}
+    CONFIGURE_COMMAND ""
+    BUILD_COMMAND
+    python ${ESP_IDF_PATH}/components/partition_table/gen_esp32part.py -q
+    --offset 0x1000 --flash-size 4MB ${ESP_IDF_PATH}/components/partition_table/partitions_singleapp.csv ${espidf_build_dir}/partitions_singleapp.bin
+    INSTALL_COMMAND ""
+    )
+
+  if(CONFIG_BUILD_OUTPUT_BIN)
+    set_property(GLOBAL APPEND PROPERTY extra_post_build_commands
+      COMMAND python ${ESP_IDF_PATH}/components/esptool_py/esptool/esptool.py
+      ARGS --chip esp32s2 elf2image --flash_mode dio --flash_freq 40m
+      -o ${CMAKE_BINARY_DIR}/zephyr/${CONFIG_KERNEL_BIN_NAME}.bin
+      ${CMAKE_BINARY_DIR}/zephyr/${CONFIG_KERNEL_BIN_NAME}.elf)
+  endif()
+
+  set_property(TARGET bintools PROPERTY disassembly_flag_inline_source)
+
+  add_dependencies(app EspIdfBootloader EspPartitionTable)
+
+  board_finalize_runner_args(esp32 "--esp-flash-bootloader=${espidf_build_dir}/bootloader/bootloader.bin")
+
+  board_finalize_runner_args(esp32 "--esp-flash-partition_table=${espidf_build_dir}/partitions_singleapp.bin")
+
+  board_finalize_runner_args(esp32 "--esp-boot-address=0x1000")
+
+  board_finalize_runner_args(esp32 "--esp-partition-table-address=0x8000")
+
+  board_finalize_runner_args(esp32 "--esp-app-address=0x10000")
+
+endif()

boards/xtensa/esp32s2_saola/Kconfig.board

@@ -0,0 +1,8 @@
+# ESP32S2 saola board configuration
+
+# Copyright (c) 2021 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD_ESP32S2_SAOLA
+	bool "ESP32S2 Saola Board"
+	depends on SOC_ESP32S2

boards/xtensa/esp32s2_saola/Kconfig.defconfig

@@ -0,0 +1,8 @@
+# ESP32S2 Saola board configuration
+
+# Copyright (c) 2021 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+config BOARD
+	default "esp32s2_saola"
+	depends on BOARD_ESP32S2_SAOLA

boards/xtensa/esp32s2_saola/board.cmake

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: Apache-2.0
+
+include(${ZEPHYR_BASE}/boards/common/esp32.board.cmake)

boards/xtensa/esp32s2_saola/doc/index.rst

@@ -0,0 +1,137 @@
+.. _esp32s2_saola:
+
+ESP32-S2
+########
+
+Overview
+********
+
+ESP32-S2 is a highly integrated, low-power, single-core Wi-Fi Microcontroller SoC, designed to be secure and
+cost-effective, with a high performance and a rich set of IO capabilities. [1]_
+
+The features include the following:
+
+- RSA-3072-based secure boot
+- AES-XTS-256-based flash encryption
+- Protected private key and device secrets from software access
+- Cryptographic accelerators for enhanced performance
+- Protection against physical fault injection attacks
+- Various peripherals:
+
+  - 43x programmable GPIOs
+  - 14x configurable capacitive touch GPIOs
+  - USB OTG
+  - LCD interface
+  - camera interface
+  - SPI
+  - I2S
+  - UART
+  - ADC
+  - DAC
+
+System requirements
+*******************
+
+Build Environment Setup
+=======================
+
+Some variables must be exported into the environment prior to building this port.
+Find more information at :ref:`env_vars` on how to keep this settings saved in you environment.
+
+.. note::
+
+   In case of manual toolchain installation, set :file:`ESPRESSIF_TOOLCHAIN_PATH` accordingly.
+   Otherwise, set toolchain path as below. If necessary.
+
+On Linux and macOS:
+
+.. code-block:: console
+
+   export ZEPHYR_TOOLCHAIN_VARIANT="espressif"
+   export ESPRESSIF_TOOLCHAIN_PATH="${HOME}/.espressif/tools/xtensa-esp32s2-elf/esp-2020r3-8.4.0/xtensa-esp32s2-elf"
+
+On Windows:
+
+.. code-block:: console
+
+   # on CMD:
+   set ESPRESSIF_TOOLCHAIN_PATH=%USERPROFILE%\.espressif\tools\xtensa-esp32s2-elf\esp-2020r3-8.4.0\xtensa-esp32s2-elf
+   set ZEPHYR_TOOLCHAIN_VARIANT=espressif
+
+   # on PowerShell
+   $env:ESPRESSIF_TOOLCHAIN_PATH="$env:USERPROFILE\.espressif\tools\xtensa-esp32s2-elf\esp-2020r3-8.4.0\xtensa-esp32s2-elf"
+   $env:ZEPHYR_TOOLCHAIN_VARIANT="espressif"
+
+Finally, retrieve required submodules to build this port. This might take a while for the first time:
+
+.. code-block:: console
+
+   west espressif update
+
+.. note::
+
+    It is recommended running the command above after :file:`west update` so that submodules also get updated.
+
+Flashing
+========
+
+The usual ``flash`` target will work with the ``esp32s2_saola`` board
+configuration. Here is an example for the :ref:`hello_world`
+application.
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/hello_world
+   :board: esp32s2_saola
+   :goals: flash
+
+Refer to :ref:`build_an_application` and :ref:`application_run` for
+more details.
+
+It's impossible to determine which serial port the ESP32-S2 board is
+connected to, as it uses a generic RS232-USB converter.  The default of
+``/dev/ttyUSB0`` is provided as that's often the assigned name on a Linux
+machine without any other such converters.
+
+The baud rate of 921600bps is recommended.  If experiencing issues when
+flashing, try halving the value a few times (460800, 230400, 115200,
+etc).
+
+All flashing options are now handled by the :ref:`west` tool, including flashing
+with custom options such as a different serial port.  The ``west`` tool supports
+specific options for the ESP32-S2 board, as listed here:
+
+  --esp-idf-path ESP_IDF_PATH
+                        path to ESP-IDF
+  --esp-device ESP_DEVICE
+                        serial port to flash, default /dev/ttyUSB0
+  --esp-baud-rate ESP_BAUD_RATE
+                        serial baud rate, default 921600
+  --esp-flash-size ESP_FLASH_SIZE
+                        flash size, default "detect"
+  --esp-flash-freq ESP_FLASH_FREQ
+                        flash frequency, default "40m"
+  --esp-flash-mode ESP_FLASH_MODE
+                        flash mode, default "dio"
+  --esp-tool ESP_TOOL   if given, complete path to espidf. default is to
+                        search for it in [ESP_IDF_PATH]/components/esptool_py/
+                        esptool/esptool.py
+  --esp-flash-bootloader ESP_FLASH_BOOTLOADER
+                        Bootloader image to flash
+  --esp-flash-partition_table ESP_FLASH_PARTITION_TABLE
+                        Partition table to flash
+
+For example, to flash to ``/dev/ttyUSB2``, use the following command after
+having build the application in the ``build`` directory:
+
+
+.. code-block:: console
+
+   west flash -d build/ --skip-rebuild --esp-device /dev/ttyUSB2
+
+
+References
+**********
+
+.. [1] https://www.espressif.com/en/products/socs/esp32-s2
+.. _`ESP32S2 Technical Reference Manual`: https://espressif.com/sites/default/files/documentation/esp32-s2_technical_reference_manual_en.pdf
+.. _`ESP32S2 Datasheet`: https://www.espressif.com/sites/default/files/documentation/esp32-s2_datasheet_en.pdf

boards/xtensa/esp32s2_saola/esp32s2_saola.dts

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2021 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/dts-v1/;
+
+#include <espressif/esp32s2.dtsi>
+
+/ {
+	model = "esp32s2_saola";
+	compatible = "espressif,esp32s2";
+
+	chosen {
+		zephyr,sram = &sram0;
+	};
+};

boards/xtensa/esp32s2_saola/esp32s2_saola.yaml

@@ -0,0 +1,6 @@
+identifier: esp32s2_saola
+name: ESP32-S2
+type: mcu
+arch: xtensa
+toolchain:
+  - espressif

boards/xtensa/esp32s2_saola/esp32s2_saola_defconfig

@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_XTENSA_RESET_VECTOR=n
+
+CONFIG_BOARD_ESP32S2_SAOLA=y
+CONFIG_SOC_ESP32S2=y
+CONFIG_MAIN_STACK_SIZE=2048
+
+CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=240000000
+
+CONFIG_XTENSA_USE_CORE_CRT1=n
+
+CONFIG_GEN_ISR_TABLES=y
+CONFIG_GEN_IRQ_VECTOR_TABLE=n
+
+CONFIG_BOOTLOADER_ESP_IDF=y

cmake/toolchain/espressif/generic.cmake

@@ -10,8 +10,19 @@ set(COMPILER gcc)
 set(LINKER ld)
 set(BINTOOLS gnu)
 
-set(CROSS_COMPILE_TARGET xtensa-esp32-elf)
-set(SYSROOT_TARGET       xtensa-esp32-elf)
+file(GLOB toolchain_paths
+  LIST_DIRECTORIES true
+  ${TOOLCHAIN_HOME}
+  )
+
+if(toolchain_paths)
+  list(GET toolchain_paths 0 soc_toolchain_path)
+
+  get_filename_component(soc_toolchain "${soc_toolchain_path}" NAME)
+
+  set(CROSS_COMPILE_TARGET ${soc_toolchain})
+  set(SYSROOT_TARGET       ${soc_toolchain})
+endif()
 
 set(CROSS_COMPILE ${TOOLCHAIN_HOME}/bin/${CROSS_COMPILE_TARGET}-)
 set(SYSROOT_DIR   ${TOOLCHAIN_HOME}/${SYSROOT_TARGET})

dts/xtensa/espressif/esp32s2.dtsi

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2021 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include <mem.h>
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu0: cpu@0 {
+			device_type = "cpu";
+			compatible = "cadence,tensilica-xtensa-lx7";
+			reg = <0>;
+		};
+	};
+
+	soc {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		compatible = "simple-bus";
+		ranges;
+
+		sram0: memory@3ffb0000 {
+			compatible = "mmio-sram";
+			reg = <0x3ffb0000 0x50000>;
+		};
+	};
+
+};

soc/xtensa/esp32s2/CMakeLists.txt

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_sources(
+  soc.c
+  )

soc/xtensa/esp32s2/Kconfig.defconfig

@@ -0,0 +1,29 @@
+# ESP32S2 board configuration
+
+# Copyright (c) 2021 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+if SOC_ESP32S2
+
+config SOC
+	default "esp32s2"
+
+config GEN_ISR_TABLES
+	default y
+
+config GEN_IRQ_VECTOR_TABLE
+	default n
+
+config XIP
+	default n
+
+config ISR_STACK_SIZE
+	default 2048
+
+config IRQ_OFFLOAD_INTNUM
+	default 7
+
+config MP_NUM_CPUS
+	default 1
+
+endif