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Linux Kernel - 4.19

Last modified by Microchip on 2025/03/03 06:28

Linux 4.19 for AT91 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/linux4sam/linux-at91/tree/linux-4.19-at91

Tag

linux4sam_6.2-icp tag

Enhancements are added on top of the official v4.19 Linux kernel tag where most of the Microchip SoC features are already supported. Note as well that we re-integrate each and every stable kernel release on top of this Long Term Support (LTS) kernel revision. This means that each v4.19.x version is merged in our branch.

Here is a little summary of the main additional enhancements:

  • Integration of stable kernel updates up to v4.19.78
  • Added support for SAMA5D2-ICP board
  • SAMA5D2 ICP drivers:
    • MCP16502 PMIC driver
    • KSZ 8563 ethernet switch driver
    • USB 2534 hub generic driver
    • LAN7850 driver with suspend / resume fix
    • Driver for the WILC3000 and WILC1000 release 15.2 in place in the Linux4SAM kernel and ready to use

linux4sam_6.2 tag

Enhancements are added on top of the official v4.19 Linux kernel tag where most of the Microchip SoC features are already supported. Note as well that we re-integrate each and every stable kernel release on top of this Long Term Support (LTS) kernel revision. This means that each v4.19.x version is merged in our branch.

Here is a little summary of the main additional enhancements:

  • SAM9X60 SoC drivers:
    • PLL Fractional support
    • PIT64 driver used for clock event
    • PIO drive strength and slew rate support
    • PWM support
    • QSPI controller support
    • NAND controller support
    • ISI support
    • ADC support
    • Reworked USB gadget driver. Updated endpoint allocation scheme. Fixed driver when working in FIFO mode only
    • I2S Multi Channel driver with support of up to 8 channels in TDM mode
    • Power management: ULP0 PM and Idle
    • Watchdog support
    • TRNG support
    • RTC support
  • SAMA5D27 WLSOM1 drivers:
    • Backup and self-refresh support for LPDDR2
    • PTC support for QT1 Mutual/Self Capacitance and Q2 wings

linux4sam_6.1 tag

Enhancements are added on top of the official v4.19 Linux kernel tag where most of the Microchip SoC features are already supported. Note as well that we re-integrate each and every stable kernel release on top of this Long Term Support (LTS) kernel revision. This means that each v4.19.x version is merged in our branch.

Here is a little summary of the main additional enhancements:

  • Integration of stable kernel updates up to v4.19.56
  • Redesign of the Image Sensor Controller (ISC) driver with new White balance enhanced features.
  • Driver for the WILC3000 and WILC1000 release 15.2 in place in the Linux4SAM kernel and ready to use
  • TWI hardware filters support that filter out possible glitches on the TWI wires for both SAMA5D4 Xplained and SAMA5D2 Xplained
  • Add 9bit/Multidrop support in USART driver
  • PIOBU pin controller driver
  • MCP16502 PMIC driver
  • ACT8945A: PM support (integrated in mainline)
  • Ethernet: add runtime PM support (integrated in mainline)
  • Ethernet: add backup and self-refresh support (integrated in mainline)
  • Ethernet: use of NAPI GRO helpers to improve RX performance
  • QSPI: move driver under the SPI-MEM interface. The controller can be used with NAND or NOR flashes.
  • Support for Omnivision ov5640 now available for both SAMA5D2 Xplained and SAMA5D27 SOM1 EK

Getting Kernel sources

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

$ git clone git://github.com/linux4sam/linux-at91.git
Cloning into 'linux-at91'...
remote: Enumerating objects: 5812545, done.
remote: Total 5812545 (delta 0), reused 0 (delta 0), pack-reused 5812545
Receiving objects: 100% (5812545/5812545), 1.63 GiB | 4.89 MiB/s, done.
Resolving deltas: 100% (4862825/4862825), done.
Checking connectivity... done.
Checking out files: 100% (56330/56330), done.
$ cd linux-at91

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 repositoryhttps://www.linux4sam.org/pub/TWiki/TWikiDocGraphics/external-link.gif to your usual Linux git tree. It will save you a lot of bandwidth and download time:

$ git remote add linux4sam git://github.com/linux4sam/linux-at91.git
$ git remote update linux4sam
Fetching linux4sam
From git://github.com/linux4sam/linux-at91
 * [new branch]                linux-2.6.39-at91 -> linux4sam/linux-2.6.39-at91
 * [new branch]                linux-3.10-at91 -> linux4sam/linux-3.10-at91
 * [new branch]                linux-3.15-at91 -> linux4sam/linux-3.15-at91
 * [new branch]                linux-3.18-at91 -> linux4sam/linux-3.18-at91
 * [new branch]                linux-3.4.9-at91 -> linux4sam/linux-3.4.9-at91
 * [new branch]                linux-3.6.9-at91 -> linux4sam/linux-3.6.9-at91
 * [new branch]                linux-4.1-at91 -> linux4sam/linux-4.1-at91
 * [new branch]                linux-4.4-at91 -> linux4sam/linux-4.4-at91
 * [new branch]                linux-4.9-at91 -> linux4sam/linux-4.9-at91
 * [new branch]                linux-4.14-at91 -> linux4sam/linux-4.14-at91
 * [new branch]                linux-4.19-at91 -> linux4sam/linux-4.19-at91
 * [new branch]                master     -> linux4sam/master

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

$ git branch -r
  origin/HEAD -> origin/master
  origin/linux-2.6.39-at91
  origin/linux-3.10-at91
  origin/linux-3.15-at91
  origin/linux-3.18-at91
  origin/linux-3.4.9-at91
  origin/linux-3.6.9-at91
  origin/linux-4.1-at91
  origin/linux-4.4-at91
  origin/linux-4.9-at91
  origin/linux-4.14-at91
  origin/linux-4.19-at91
  origin/master
$ git checkout origin/linux-4.19-at91 -b linux-4.19-at91
Branch linux-4.19-at91 set up to track remote branch linux-4.19-at91 from origin.
Switched to a new branch 'linux-4.19-at91'

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
  • at91_dt_defconfig: for at91sam ARM926 series chips
  • sama5_defconfig: for SAMA5 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.(This link points to a non-existent 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-4.1.0-linux4sam_5.3+
Created:      Fri Sep  9 17:02:45 2016
Image Type:   ARM Linux Kernel Image (uncompressed)
Data Size:    3441072 Bytes = 3360.42 kB = 3.28 MB
Load Address: 20008000
Entry Point:  20008000
  Image arch/arm/boot/uImage is ready


make ARCH=arm dtbs

[..]
  DTC     arch/arm/boot/dts/at91-kizbox2.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-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-tse850-3.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-sama5d4ek_isi.dtb
  DTC     arch/arm/boot/dts/at91-vinco.dtb
[..]

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

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