Exploring-Linux-RPI4

Minimal workspace for:

• Raspberry Pi kernel (submodule)
• Out-of-tree kernel modules
• Cross-compilation workflow

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Structure

.
├── kernel/           # RPi Linux (submodule)
├── kernel_headers/   # Exported headers (userspace only)
├── modules/          # Custom modules
├── build_kernel.sh
└── build_module.sh

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Update Kernel

git submodule sync
git submodule update --init --remote kernel

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Prepare Kernel (REQUIRED for modules)

cd kernel
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- bcm2711_defconfig
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- modules_prepare

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Build Module

./build_module.sh <module_name> build

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Key Rule

• Use kernel/ → for module builds
• Do NOT use kernel_headers/ for modules

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(Optional) Full Kernel Build

./build_kernel.sh build

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Fix: Detached HEAD in submodule

cd kernel
git checkout -B rpi-6.12.y origin/rpi-6.12.y

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Toolchain

sudo apt install gcc-aarch64-linux-gnu

References

Build and copy kernel:

• https://www.raspberrypi.com/documentation/computers/linux_kernel.html

Kernel modules inspired from:

• https://github.com/Johannes4Linux/Linux_Driver_Tutorial/tree/main
• https://github.com/Embetronicx/Tutorials/tree/master/Linux/Device_Driver

Pinout reference:

• https://pinout.xyz/