EFR32xG25 Secure Element example

[dgarske]

Add EFR32xG25 Secure Element example

Headless slc-cli project that runs the wolfCrypt test and benchmark, and an optional on-device TLS 1.3 test, on an EFR32xG25 with crypto routed to the Secure Element through the wolfSSL crypto callback port.

Needs the port from wolfSSL PR wolfSSL/wolfssl#11267

What it adds

embedded/efr32xg25/:

• wolfcrypt_test.slcp, user_settings.h - project and shared configuration
• app.c - entry point, prints the SE firmware version and Secure Vault level, then runs the test and benchmark
• tls13_test.c - optional TLS 1.3 client and server, both on the device
• build.sh, flash.sh - slc generate plus make, and commander flash
• README.md - toolchain install, build, and the measured hardware-versus-software table

Design notes

• Builds from a wolfSSL source checkout, no prebuilt library. It expects one beside wolfssl-examples; WOLFSSL_ROOT overrides that. slc resolves every path: entry relative to the .slcp file, so a non-default root is rewritten to a path relative to the example directory and the rewritten copy has to stay there.
• The toolchain installs headlessly with Silicon Labs Tool. As of SLC-CLI v6 the CLI is no longer a direct download, so build.sh and flash.sh read ~/.silabs/sdks.json and ~/.silabs/tools.json rather than hardcoding paths.
• WOLFSSL_SILABS_CRYPTOCB points WC_USE_DEVID at the SE, so the stock benchmark measures every algorithm twice and labels the rows HW and SW. Each comparison therefore comes from one run on one part.
• The kit has no RTC, so app.c supplies a _gettimeofday() seeded from the build date, overriding newlib's weak stub. Without it every certificate reads as not yet valid. That is adequate for a self-contained demo and nothing more.

Hardware and test status

Validated on an EFR32FG25B222F1920IM56 (BRD4270B, Secure Vault High, SE firmware 2.2.0):

• wolfcrypt_test full PASS, benchmark clean.
• TLS 1.3 handshake and application data for TLS13-AES128-GCM-SHA256, TLS13-AES256-GCM-SHA384 and TLS13-CHACHA20-POLY1305-SHA256, all pass.

Scope

The TLS 1.3 test and the Thumb2 assembly software path are both opt-in blocks at the top of user_settings.h; their sources are already in the project and compile to nothing while off.

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Pull request overview

Adds a headless Simplicity Studio (slc-cli) example project for EFR32xG25 that runs wolfcrypt_test + benchmark, with optional on-device TLS 1.3 mem-IO testing, all routed through the Silicon Labs Secure Element via wolfSSL crypto callbacks.

Changes:

• Adds an slc project (.slcp) that builds wolfSSL sources from a neighboring checkout and configures required Silicon Labs components.
• Introduces shared user_settings.h for Secure Element offload + optional TLS 1.3 and Thumb2 asm toggles.
• Adds headless build.sh / flash.sh scripts and documentation for toolchain setup, build/flash, and measured results.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
embedded/efr32xg25/wolfcrypt_test.slcp	New SLC project definition, sources, components, and build configuration for the example.
embedded/efr32xg25/user_settings.h	Shared wolfSSL/wolfCrypt configuration for SE crypto-callback routing and optional TLS/asm features.
embedded/efr32xg25/app.c	Main entry point: prints SE info, runs tests/bench, optional TLS 1.3, and provides _gettimeofday() when needed.
embedded/efr32xg25/tls13_test.c	Optional TLS 1.3 on-device handshake + record-layer test over an in-memory transport.
embedded/efr32xg25/build.sh	Headless generation/build script that locates SDK/tools via ~/.silabs/*.json registries.
embedded/efr32xg25/flash.sh	Flash/reset script using Silicon Labs Commander located via tools.json.
embedded/efr32xg25/README.md	Setup and usage docs plus performance measurements and notes.
embedded/efr32xg25/.gitignore	Ignores generated build output and local rewritten .slcp.

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