Build drivers from source for rpi

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The main resources in this section are the official piOS building method. We use the method of cross-compilation, and the 5.4.72 version of 32bitOS is taken as an example.

The following operations are done on ubuntu PC.

1 Build cross-compilation environment on Ubuntu 64-bitoperating system)

sudo apt install git bc bison flex libssl-dev make libc6-dev libncurses5-dev

• 32-bit piOS target version

sudo apt install crossbuild-essential-armhf

• 64-bit piOS target version

sudo apt install crossbuild-essential-arm64

2 Download the standard version of the piOS source code

2.1 Confirm the piOS version of your raspberry Pi

• Release version

$ uname -a

Linux raspberrypi 5.4.72-v7l+ #1356 SMP Thu Oct 22 13:57:51 BST 2020 armv7l GNU/Linux

• Code tag

$ cp /usr/share/doc/raspberrypi-bootloader/changelog.Debian.gz ./

gunzip changelog.Debian.gz

Check the top lines and you will know the tag.

2.2 There are two ways to get the source code of the version you want:

1. using git to clone the corresponding branch and checkout the corresponding tag.

git clone --branch rpi-5.4.y https://github.com/raspberrypi/linux

git checkout raspberrypi-kernel_1.20201022-1

PS: Please replace the above two commands with your own corresponding versions.

2. Manually download the version code of the corresponding tag directly from the link below.

https://github.com/raspberrypi/linux/tags

3 Patch our code to kernel

• Driver source code

camera driver path is ： linux/drivers/media/i2c，copy our camera module drivers to this path.

• Modify the the Makefile and Kconfig files

Modify the Config and Makefile in the same path，add the corresponding camera driver.

• dts file

dts file path is ：linux/arch/arm/boot/dts/overlays，copy our [camera]-overlay.dts files to this path.

• Modify dts Makefile

Modify the Makefile in the same path，add the corresponding dts compilation option.

5 Preparing

• For Raspberry Pi 1, Zero and Zero W, and Raspberry Pi Compute Module 1 default (32-bit only) build configuration

KERNEL=kernel

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- bcmrpi_defconfig

• For Raspberry Pi 2, 3, 3+ and Zero 2 W, and Raspberry Pi Compute Modules 3 and 3+ default 32-bit build configuration

KERNEL=kernel7

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- bcm2709_defconfig

• For Raspberry Pi 4 and 400, and Raspberry Pi Compute Module 4 default 32-bit build configuration

KERNEL=kernel7l

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- bcm2711_defconfig

• For Raspberry Pi 3, 3+, 4, 400 and Zero 2 W, and Raspberry Pi Compute Modules 3, 3+ and 4 default 64-bit build configuration

KERNEL=kernel8

make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- bcm2711_defconfig

6 Add compilation options

• 32-bit version

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- menuconfig

• 64-bit version

make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig

Add the compilation options by the corresponding camera module, for 5.4 version kernel the path is driver-- > multimedia-- > i2C.

For 5.10 version kernel,the path is Device Drivers --> Multimedia Support --> Media ancillary drivers --> Camera sensor devices.

6.1 Build

• 32-bit version

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- zImage modules dtbs -j4

• 64-bit version

make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- Image modules dtbs -j4

7 Frequently Questions

• disagrees about version of symbol module_layout

After the system has been booted, dmesg can see this error reported when the driver of camera is loaded. It is caused by the mismatch between the original piOS version on the board and the compiled camera driver version.

It is recommended to refer to this link to recompile from the code and install Image, dtb, modules as a whole.

8 References

https://www.raspberrypi.org/documentation/linux/kernel/building.md