RP2350

Introduction

RP2350 features a dual-core Arm Cortex-M33 processor with 520 kiB on-chip SRAM, support for up to 16 MB of off-chip flash and a wide range of flexible I/O option including I2C, SPI, and - uniquely - Programmable I/O (PIO). With its security features RP2350 offers significant enhancements over RP2040.

This platform port supports TF-M regression tests (Secure and Non-Secure) with Isolation Level 1 and 2.

Note

Only the GNU toolchain is supported.

Note

Only the “profile_medium” predefined profile is supported.

Building TF-M

Follow the generic build instructions in Building instructions and specify the platform name by setting -DTFM_PLATFORM=rpi/rp2350.

Note

This platform port relies on the Raspberry Pi Pico SDK. Make sure it is either cloned locally or available to download during build. SDK version used for testing: SDK 2.0.0 release.

Note

Building the default platform configuration requires the board to be provisioned first. For this the provision bundle needs to be built and run on the board with -DPLATFORM_DEFAULT_PROVISIONING=OFF. The binary must be placed in flash at the start address defined by PROVISIONING_BUNDLE_START. One way to do this is to generate a .uf2 file containing the bundle at the start address and copy it to the board. There is an example in the provided pico_uf2.sh script and in the description below.

If -DPLATFORM_DEFAULT_PROVISIONING=OFF and -DTFM_DUMMY_PROVISIONING=ON then the keys in the <TF-M source dir>/platform/ext/common/provisioning_bundle/provisioning_config.cmake and the default MCUboot signing keys will be used for provisioning.

If -DPLATFORM_DEFAULT_PROVISIONING=OFF and -DTFM_DUMMY_PROVISIONING=OFF are set then unique assets can be used for provisioning. The keys and seeds can be changed by passing the new values to the build command, or by setting the -DPROVISIONING_KEYS_CONFIG config option to point to a .cmake config file that contains the keys. An example config file is available at <TF-M source dir>/platform/ext/common/provisioning_bundle/provisioning_config.cmake, otherwise new random values are going to be generated and used. For the image signing the ${MCUBOOT_KEY_S} and ${MCUBOOT_KEY_NS} will be used. These variables should point to .pem files that contain the private keys for signing the code. The respective public keys (or hashes of them) are going to be written in the provisioning data, i.e. in the autogenerated provisioning_data.c.

If -DMCUBOOT_GENERATE_SIGNING_KEYPAIR=ON is set then a new private key is going to be generated and used to sign the binaries.

The new generated key can be found in the <build dir>/bin directory or in the <install dir>/image_signing/keys after installation. The generated provisioning_data.c file can be found at <build dir>/platform/target/provisioning/provisioning_data.c

Note

The provisioning bundle generation depends on pyelftools that has to be installed before running the commands described above:

pip3 install pyelftools

Example of build instructions for regression tests with dummy keys:

Building Secure side with provisioning bundle:

Note

Add optionally:

-DTFM_MULTI_CORE_TOPOLOGY=ON for multicore support
-DPICO_SDK_PATH=<abs-path-to-pico-sdk-dir> for a pre-fetched Pico SDK

cmake -S <TF-M-tests source dir>/tests_reg/spe \
-B <TF-M-tests source dir>/tests_reg/spe/build_rpi_single \
-DTFM_PLATFORM=rpi/rp2350 \
-DTFM_TOOLCHAIN_FILE=<TF-M source dir>/toolchain_GNUARM.cmake \
-DCONFIG_TFM_SOURCE_PATH=<TF-M source dir> \
-DTFM_PROFILE=profile_medium \
-DPLATFORM_DEFAULT_PROVISIONING=OFF \
-DTEST_S=ON \
-DTEST_NS=ON

cmake --build <TF-M-tests source dir>/tests_reg/spe/build_rpi_single -- -j8 install

Building Non-Secure side:

cmake -S <TF-M-tests source dir>/tests_reg \
-B <TF-M-tests source dir>/tests_reg/build_rpi_single \
-DCONFIG_SPE_PATH=<TF-M-tests source dir>/tests_reg/spe/build_rpi_single/api_ns \
-DTFM_TOOLCHAIN_FILE=<TF-M-tests source dir>/tests_reg/spe/build_rpi_single/api_ns/cmake/toolchain_ns_GNUARM.cmake

cmake --build <TF-M-tests source dir>/tests_reg/build_rpi_single -- -j8

Binaries need to be converted with a small script pico_uf2.sh. It uses uf2conv.py and it depends on uf2families.json: both those files need to be copied into the same place where pico_uf2.sh runs. Also, you may need to give executable permissions to both pico_uf2.sh and uf2conv.py. The tool takes the combined and signed S and NS images in .bin format, and outputs .uf2. It also generates the .uf2 for the bootloader (bl2.uf2) and the provisioning bundle.

pico_uf2.sh <TF-M-tests source dir> build_rpi_single

Then just copy the bl2.uf2 and tfm_s_ns_signed.uf2 files to the board, one at a time. It will run the BL2, S and NS tests and print the results to the UART (Baud rate must be set to 115200). If the board needs to be provisioned, the .uf2 file containing the provisioning bundle needs to be copied before tfm_s_ns_signed.uf2. It only needs to be done once.

Note

If a different application was copied to the board before, erasing the flash might be necessary.

Erasing the flash

Generating flash sized image of zeros can be done with the truncate command, then it can be converted to the `uf2 format with the uf2conv.py utility. The resulting uf2 file then needs to be copied to the board. Current platform flash size is 2 MB, please adjust size based on your board specs, i.e. PICO_FLASH_SIZE_BYTES:

truncate -s 2M nullbytes2M.bin
uf2conv.py nullbytes2M.bin --base 0x10000000 --convert --output nullbytes2M.uf2 --family 0xe48bff59

SPDX-License-Identifier: BSD-3-Clause

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