Trusty System Basics - Hardware & Toolchain Preparation

4. Hardware & Toolchain Preparation

4.1 Recommended Development Boards

For Trusty OS development, we recommend the following platforms:

Option 1: Google Pixel Phones (Recommended)

Pixel 3/3XL - Excellent support for Trusty development
Pixel 4/4XL - More recent hardware with good documentation
Pixel 5 - Supports latest Trusty features

Note: Pixel devices provide the most authentic TrustZone environment with production-grade hardware security features.

Option 2: QEMU Emulator (For Beginners)

AOSP's built-in ARM emulator with Trusty support
Good for initial learning and testing
Doesn't require physical hardware

Hardware Considerations

When selecting hardware for Trusty development:

Ensure the device supports fastboot oem commands
Verify bootloader unlock capability
Check for available Trusty TEE debugging interfaces
Consider device-specific Trusty implementations

4.2 AOSP Integrated Build Environment Configuration

Trusty development requires the Android Open Source Project (AOSP) build environment.

System Requirements

Ubuntu 18.04/20.04 LTS (recommended)
64-bit system
At least 16GB RAM (32GB recommended)
250GB+ free disk space (SSD strongly recommended)
Python 3.6+

Setup Steps

Install required packages:

sudo apt-get install git-core gnupg flex bison build-essential zip curl zlib1g-dev \
gcc-multilib g++-multilib libc6-dev-i386 lib32ncurses5-dev x11proto-core-dev \
libx11-dev lib32z1-dev libgl1-mesa-dev libxml2-utils xsltproc unzip fontconfig

Configure Git:

git config --global user.name "Your Name"
git config --global user.email "you@example.com"

Install repo tool:

mkdir ~/bin
curl https://storage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
chmod a+x ~/bin/repo

Add to PATH in ~/.bashrc:
```
export PATH=~/bin:$PATH
```

Initialize AOSP repository (choose branch):

mkdir ~/aosp
cd ~/aosp
repo init -u https://android.googlesource.com/platform/manifest -b android-12.0.0_r1

Sync the source code:
```
repo sync -j4
```

Pro Tip: Use repo sync -j$(nproc --all) to use all available CPU cores for faster synchronization.

4.3 Cross-Compilation Toolchain (AOSP Prebuilts)

AOSP provides prebuilt toolchains for Trusty development.

Toolchain Components

ARM GCC: prebuilts/gcc/linux-x86/arm/arm-eabi-4.8
ARM64 GCC: prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9
Clang: prebuilts/clang/host/linux-x86/clang-4639204
Trusty-specific tools: trusty/prebuilts

Environment Setup

Add these to your .bashrc or build script:

export CROSS_COMPILE=arm-eabi-
export PATH=$PATH:<AOSP_ROOT>/prebuilts/gcc/linux-x86/arm/arm-eabi-4.8/bin
export TRUSTY_TOP=<AOSP_ROOT>/trusty

Building Trusty Components

Navigate to Trusty directory:
```
cd $TRUSTY_TOP
```
Set up build environment:
```
. ./build/envsetup.sh
```
Select target device:
```
lunch trusty_<device>-userdebug
```
Build Trusty OS:
```
make -j$(nproc --all)
```

Important Notes

Always use the toolchain versions specified in AOSP manifests
Mixing toolchain versions can cause subtle TrustZone issues
For production builds, consider using the trusty_release target