Linux Kernel - 6.1

Linux 6.1 for MPU source code

The Linux kernel for Microchip ARM-Based MPUs (aka AT91) is distributed as a GIT tree hosted on GitHub as a fork of the official Linus Torvalds' git tree. The objective of the Microchip Linux team is to integrate all the AT91-related material in the official Linux Kernel.
Before completing this inclusion process, which can take time, this website provides the Linux4SAM Linux Kernel git tree for AT91 devices at:

https://github.com/linux4microchip/linux/tree/linux-6.1-mchp

Required packages

You must install essential host packages on your build host. These requirements are listed in the Linux kernel documentation with the chapter Install build requirements. You must follow this process which includes, but not limited to, the following packages:

build-essential
flex
bison
git
perl-base
libssl-dev
libncurses5-dev
libncursesw5-dev
ncurses-dev

Getting Kernel sources

To get the source code, you have to clone the repository:

$ git clone https://github.com/linux4microchip/linux.git
Cloning into 'linux'...
remote: Enumerating objects: 8587836, done.
remote: Total 8587836 (delta 0), reused 0 (delta 0), pack-reused 8587836
Receiving objects: 100% (8587836/8587836), 3.49 GiB | 13.44 MiB/s, done.
Resolving deltas: 100% (7117887/7117887), done.
Updating files: 100% (70687/70687), done.
$ cd linux

The source code has been taken from the master branch which is pointing on the latest branch we use.

Note that you can also add this Linux4SAM repository as a remote GIT repository to your usual Linux git tree. It will save you a lot of bandwidth and download time:

$ git remote add linux4microchip https://github.com/linux4microchip/linux.git
$ git remote update linux4microchip
Fetching linux4icrochip
From https://github.com/linux4microchip/linux
 * [new branch]                linux-5.10-mchp -> linux4microchip/linux-5.10-mchp
 * [new branch]                linux-5.15-mchp -> linux4microchip/linux-5.15-mchp
 * [new branch]                linux-6.1-mchp -> linux4microchip/linux-6.1-mchp
 * [new branch]                master     -> linux4microchip/master

If you want to use another branch, you can list them and use one of them by doing this:

$ git branch -r
  origin/HEAD -> origin/master
  origin/linux-5.10-mchp
  origin/linux-5.15-mchp
  origin/linux-6.1-mchp
  origin/master
$ git checkout origin/linux-6.1-mchp -b linux-6.1-mchp
Branch linux-6.1-mchp set up to track remote branch linux-6.1-mchp from origin.
Switched to a new branch 'linux-6.1-mchp'

Setup ARM Cross Compiler

Ubuntu:
In Ubuntu 22.04 LTS, you can install the ARM Cross Compiler by doing:

sudo apt-get install gcc-arm-linux-gnueabi
export CROSS_COMPILE=arm-linux-gnueabi-

Others:
For others, you can download the ARM cross compiler and setup the environment by doing:

wget -c https://developer.arm.com/-/media/Files/downloads/gnu/11.2-2022.02/binrel/gcc-arm-11.2-2022.02-x86_64-arm-none-linux-gnueabihf.tar.xz
tar -xf gcc-arm-11.2-2022.02-x86_64-arm-none-linux-gnueabihf.tar.xz
export CROSS_COMPILE=`pwd`/gcc-arm-11.2-2022.02-x86_64-arm-none-linux-gnueabihf/bin/arm-none-linux-gnueabihf-

Configure and Build the Linux kernel

Now you have to configure the Linux kernel according to your hardware. We have two default configuration at91 SoC in arch/arm/configs

arch/arm/configs/at91_dt_defconfig
arch/arm/configs/sama5_defconfig
arch/arm/configs/sama7_defconfig

at91_dt_defconfig: for SAM9 (ARM926) series chips
sama5_defconfig: for SAMA5 series chips
sama7_defconfig: for SAMA7 series chips

Now we Configure and Build kernel for board:

$ make ARCH=arm sama5_defconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  SHIPPED scripts/kconfig/zconf.tab.c
  SHIPPED scripts/kconfig/zconf.lex.c
  SHIPPED scripts/kconfig/zconf.hash.c
  HOSTCC  scripts/kconfig/zconf.tab.o
  HOSTLD  scripts/kconfig/conf
#
# configuration written to .config
#

At this step, you can modify default configuration using the menuconfig

$ make ARCH=arm menuconfig

Now, in the menuconfig dialog, you can easily add or remove some features. Once done, Move to <Exit> with arrows and press this button hitting the Enter key to exit from this screen.

Build the Linux kernel image, before you build you need set up the cross compile toolchain, check this section.

$ make ARCH=arm

[..]

  Kernel: arch/arm/boot/Image is ready
  Kernel: arch/arm/boot/zImage is ready

Now you have an usable compressed kernel image zImage.

If you need an uImage you can run this additional step:

make ARCH=arm uImage LOADADDR=0x20008000

[..]

  Kernel: arch/arm/boot/zImage is ready
  UIMAGE  arch/arm/boot/uImage
Image Name:   Linux-6.1.22-linux4microchip-20
Created:      Wed May  4 21:18:58 2022
Image Type:   ARM Linux Kernel Image (uncompressed)
Data Size:    5069704 Bytes = 4950.88 KiB = 4.83 MiB
Load Address: 20008000
Entry Point:  20008000
  Kernel: arch/arm/boot/uImage is ready

make ARCH=arm dtbs

[..]

  DTC     arch/arm/boot/dts/at91-kizbox2-2.dtb
  DTC     arch/arm/boot/dts/at91-kizbox3-hs.dtb
  DTC     arch/arm/boot/dts/at91-nattis-2-natte-2.dtb
  DTC     arch/arm/boot/dts/at91-sama5d27_som1_ek.dtb
  DTC     arch/arm/boot/dts/at91-sama5d27_wlsom1_ek.dtb
  DTC     arch/arm/boot/dts/at91-sama5d2_icp.dtb
  DTC     arch/arm/boot/dts/at91-sama5d2_ptc_ek.dtb
  DTC     arch/arm/boot/dts/at91-sama5d2_xplained.dtb
  DTC     arch/arm/boot/dts/at91-sama5d3_xplained.dtb
  DTC     arch/arm/boot/dts/at91-dvk_som60.dtb
  DTC     arch/arm/boot/dts/at91-gatwick.dtb
  DTC     arch/arm/boot/dts/at91-tse850-3.dtb
  DTC     arch/arm/boot/dts/at91-wb50n.dtb
  DTC     arch/arm/boot/dts/sama5d31ek.dtb
  DTC     arch/arm/boot/dts/sama5d33ek.dtb
  DTC     arch/arm/boot/dts/sama5d34ek.dtb
  DTC     arch/arm/boot/dts/sama5d35ek.dtb
  DTC     arch/arm/boot/dts/sama5d36ek.dtb
  DTC     arch/arm/boot/dts/sama5d36ek_cmp.dtb
  DTC     arch/arm/boot/dts/at91-sama5d4_ma5d4evk.dtb
  DTC     arch/arm/boot/dts/at91-sama5d4_xplained.dtb
  DTC     arch/arm/boot/dts/at91-sama5d4ek.dtb
  DTC     arch/arm/boot/dts/at91-vinco.dtb
  DTC     arch/arm/boot/dts/at91-sama7g5ek.dtb
  DTC     arch/arm/boot/dts/at91-sam9x60_curiosity.dtb

[..]

If the building process is successful, the final images can be found under arch/arm/boot/ directory.

Recent FAQ

linux-6.1-mchp: • Media Controller: What is Media controller and how to use it with SAM products.. (Sam9x75Curiosity, Sama7g5-ek, Sama5d27WLSom1EK, Sama5d27Som1EK, Sama5d2Xplained)
• Using Atmel DRMDriver: Using Atmel KMS/DRM LCD driver. (Sama7d65Curiosity, Sama5d29Curiosity, Sam9x75Curiosity, Sam9x60Curiosity, Sam9x60EK, Sama5d27WLSom1EK, Sama5d27Som1EK, Sama5d2PtcEK, Sama5d2Xplained, Sama5d4Xplained, Sama5d4ek, Sama5d3Xplained, Sama5d3xek)
• Using Systemd: Basic systemd user guide. (Sama7d65Curiosity, Sama5d29Curiosity, Sam9x75Curiosity, Sam9x60Curiosity, Sama7g5-ek, Sama5d2-icp, Sam9x60EK, Sama5d27WLSom1EK, Sama5d27Som1EK)
• Thermal Faq: Thermal management support on SAMA7G5. (Sama7d65Curiosity, Sama7g5-ek)
• Using SAMA 5 D 2 ADCDevice: Using the SAMA5D2-compatible ADC device. (Sama7d65Curiosity, Sama5d29Curiosity, Sam9x75Curiosity, Sam9x60Curiosity, Sama7g5-ek, Sama5d2-icp, Sam9x60EK, Sama5d27WLSom1EK, Sama5d27Som1EK, Sama5d2PtcEK, Sama5d2Xplained)
• Using Max Touch: Introduction for how to use maxTouch. (Sama5d29Curiosity, Sam9x75Curiosity, Sam9x60Curiosity)
• Crypto Config: How to configure Crypto driver. (Sama5d29Curiosity, Sam9x75Curiosity, Sam9x60Curiosity, Sama5d2-icp, Sam9x60EK, Sama5d27WLSom1EK, Sama5d27Som1EK, Sama5d2PtcEK, Sama5d2Xplained, Sama5d4Xplained, Sama5d4ek, Sama5d3Xplained, Sama5d3xek)
• USBGadget Config: Configure AT91 USB Gadget on Linux and Endpoint order management (composite USB). (Sama5d29Curiosity, Sam9x75Curiosity, Sam9x60Curiosity, Sama5d2-icp, Sam9x60EK, Sama5d27WLSom1EK, Sama5d27Som1EK, Sama5d2PtcEK, Sama5d2Xplained, Sama5d4Xplained, Sama5d4ek, Sama5d3Xplained, Sama5d3xek, AT91sam9x5-ek, other AT91SAM9 boards)
• Pwm Faq: PWM Driver. (Sama5d29Curiosity, Sam9x75Curiosity, Sam9x60Curiosity, Sam9x60EK, Sama5d27WLSom1EK, Sama5d27Som1EK, Sama5d2PtcEK, Sama5d2Xplained, Sama5d4Xplained, Sama5d3Xplained, Sama5d3xek)
• Using I 2 SC: How to use I2SC. (Sam9x75Curiosity, Sama7g5-ek, Sam9x60EK, Sama5d2Xplained)
• ISCWhite Balance Features: White balance features of the Image sensor controller.. (Sam9x75Curiosity, Sama7g5-ek, Sama5d27WLSom1EK, Sama5d27Som1EK, Sama5d2Xplained)
• Sama 7 g 5 Xisc: Detailed explanation of the sama7g5 image acquisition pipeline. (Sam9x75Curiosity, Sama7g5-ek)
• External Component On EBI: Connecting an external component on the External Bus Interface. (Sam9x75Curiosity, Sam9x60Curiosity, Sam9x60EK, Sama5d27Som1EK, Sama5d2PtcEK, Sama5d2Xplained, Sama5d4Xplained, Sama5d4ek, Sama5d3Xplained, Sama5d3xek, AT91sam9x5-ek)
• Sama 7 g 5 Ov 7740: Interfacing sama7g5 with parallel omnivision ov7740 sensor.. (Sama7g5-ek)
• Using ASRC: How to use ASRC. (Sama7g5-ek)
• Boot Logo: Boot Logo for At91 SOC's. (Sama5d2Xplained)