CL-SOM-AM57x: Linux: Getting started

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Introduction

This article provides an introduction on how to install the example root filesystem image on the CompuLab CL-SOM-AM57x System-on-Module / Computer-on-Module eMMC internal storage device.

Preparation steps

  • Obtain a PC workstation with a serial communication port or a free USB 2.0 Host port.
  • For networked installation you need to install a TFTP server on the host PC. For Windows machines we recommend TFTPD32 included in the Linux package for CL-SOM-AM57x (link below).
  • Download the Linux package for CL-SOM-AM57x from CompuLab website. Unzip the package to a directory on your host workstation.
  • All image files mentioned below can be found in the images subdirectory
  • Connect the host PC to the SB-SOM-AM57x base-board (connector P8) via the serial cable supplied with the evaluation kit.
    • SB-SOM-AM57x base-board features Serial-to-USB adapter available through connector P7. It can be used as an alternative debug port to connect the Host PC via the micro-USB cable supplied with the evaluation kit.
  • Start terminal emulation software on your PC. Set baud rate to 115200 bps, 8 bit per frame, 1 stop bit, no parity, no flow control.
  • Turn on the CL-SOM-AM57x evaluation system. The U-Boot boot-loader will start and you will get a command prompt.
Admolition note.png If the boot settings of your CL-SOM-AM57x are different than default, you may need to press and hold Ctrl-C while turning the CL-SOM-AM57x on, in order to get command prompt.

Boot into the installation environment (ramdisk)

The first step in CL-SOM-AM57x Linux installation is starting the installation environment (Linux kernel and Ramdisk image). This can be done using one of the following media:

Using installation environment on MMC/SD card

  • Copy kernel.img, am57xx-sbc-am57x.dtb, ramdisk.img and bootscr.img from images sub-directory of Linux package for CL-SOM-AM57x to the root directory on the first partition of the MMC/SD card.
  • Insert the MMC/SD card into the MMC/SD socket (P9) on the SB-SOM-AM57x baseboard and reset the module.
  • The installation environment boot will start automatically.
  • To start installation environment boot manually, use the following U-Boot commands:
CL-SOM-AM57x # mmc dev 0
CL-SOM-AM57x # mmc rescan
CL-SOM-AM57x # load mmc 0 0x82000000 bootscr.img
CL-SOM-AM57x # source 0x82000000

Using installation environment from USB storage device

  • Copy kernel.img, am57xx-sbc-am57x.dtb, ramdisk.img and bootscr.img from images sub-directory of Linux package for CL-SOM-AM57x to the root directory on the first partition of the USB storage device.
  • Insert USB storage device into SB-SOM-AM57x USB port P6.
  • Remove MMC/SD card from the MMC/SD socket (P9) on the SB-SOM-AM57x baseboard.
  • The installation environment boot will start automatically.
  • To start installation environment boot manually, use the following U-Boot commands:
CL-SOM-AM57x # usb start
CL-SOM-AM57x # load usb 0 0x82000000 bootscr.img
CL-SOM-AM57x # source 0x82000000

Using installation environment from TFTP server

  • Connect the SB-SOM-AM57x Ethernet port to your local network.
  • Put kernel.img, am57xx-sbc-am57x.dtb, and ramdisk.img from images sub-directory of Linux package for CL-SOM-AM57x to a location accessible by the TFTP server:
    - On Windows machine: copy kernel.img, am57xx-sbc-am57x.dtb, and ramdisk.img to the same folder and point the TFTP server to that folder
    - On Linux machine: copy kernel.img, am57xx-sbc-am57x.dtb, and ramdisk.img to TFTP server root directory, usually /tftpboot or /tftproot.

Use U-Boot dhcp command to obtain IP address

CL-SOM-AM57x # dhcp
or manually set ipaddr environment variable:
CL-SOM-AM57x # setenv ipaddr <ip address>
  • Use the following U-Boot commands to start installation environment boot:
CL-SOM-AM57x # setenv bootargs "root=/dev/ram0 rw ramdisk_size=16384 console=ttyO2,115200n8 vram=16M ip=dhcp"
CL-SOM-AM57x # tftpboot 0x88000000 am57xx-sbc-am57x.dtb
CL-SOM-AM57x # tftpboot 0x82000000 kernel.img
CL-SOM-AM57x # tftpboot 0x88080000 ramdisk.img
CL-SOM-AM57x # bootz 0x82000000 0x88080000 0x88000000

Install Kernel and Root File System Images

After the ramdisk image is loaded the Linux login prompt will appear. Login as root into the system.

compulab login: root

Mount the installation source media

The next step is installing the kernel and Root File System images. The following media can be used as a source for installation:

Mount an MMC/SD Card
  • Copy the zImage-cl-som-am57x, am57xx-sbc-am57x.dtb and the debian-armhf-image.tar.bz2 to the root directory of any partition on the MMC/SD card. The partition can be formatted either ext2/3/4 or FAT file system.
  • Insert the MMC/SD card into the SD socket (P9) on the SB-SOM-AM57x.
  • The MMC/SD card is mounted automatically under /media/mmcblk0pX. Where X is the partition number.
  • If for some reason the MMC/SD card hasn't been mounted automatically, use the following mount command:
root@compulab:~# mkdir -p /media/mmcblk0pX && mount /dev/mmcblk0pX /media/mmcblk0pX
Mount a USB Storage Device
  • Copy the zImage-cl-som-am57x, am57xx-sbc-am57x.dtb and the debian-armhf-image.tar.bz2 to the root directory of any partition on the USB storage device. The partition can be formatted either ext2/3/4 or FAT file system.
  • Plug the USB storage device to any USB host port (P6) on the SB-SOM-AM57x.
  • The USB device is mounted automatically under /media/sdXY. Where X is the device letter and Y is the partition number.
  • If for some reason the USB storage device hasn't been mounted automatically, use the following mount command:
root@compulab:~# mkdir -p /media/sdXY && mount /dev/sdXY /media/sdXY
Mount an NFS drive
  • Connect the CL-SOM-AM57x Ethernet port (P21) to your local network.
  • Copy the zImage-cl-som-am57x, am57xx-sbc-am57x.dtb and the debian-armhf-image.tar.bz2 to a directory exported through NFS.
  • During Ramdisk image booting the CL-SOM-AM57x attempts to obtain an IP address using DHCP. If from some reason the IP address has not been obtained, use the following commands to obtain IP address for the CL-SOM-AM57x:
    • Obtain IP using DHCP:
      root@compulab:~# ifup eth1
    or
    • If there is no DHCP server on the network, you can set a static IP address using ifconfig:
      root@compulab:~# ifconfig eth1 <ip address>
  • Mount the NFS share containing the zImage-cl-som-am57x, am57xx-sbc-am57x.dtb and the debian-armhf-image.tar.bz2 files:
root@compulab:~#  mount -o nolock <host ip>:/path/to/nfs/share /mnt/net

Install Linux kernel and filesystem images

The Linux kernel and Root File System images can be installed on the following media:

Install Images on eMMC
Admolition note.png The below procedure will work only on empty eMMC chip. If you have already used the eMMC, please delete all the partitions before proceeding.
  • In this subsection the term /mount/point can be:
    • /mnt/net if NFS is used.
    • /media/mmcblk1pX if an MMC/SD card is used, where X is the partition number.
    • /media/sdXY if USB storage is used, where X is the USB drive letter and Y is the partition number.
Admolition note.png In the below procedure the first (boot) partition can be either FAT32 or EXT2/3/4. The example below is only for FAT32 filesystem.
  • Create two partitions for the Linux kernel (FAT32 100M) and root file system (EXT4 the rest of the disk) on the eMMC:
root@compulab:~# echo -e "n\np\n1\n2048\n204800\na\n1\nt\nc\nn\np\n2\n204801\n\nw\neof\n" | fdisk -u /dev/mmcblk0
  • Refresh the device nodes:
root@compulab:~# mdev -s && umount /dev/mmcblk0p1 && umount /dev/mmcblk0p2
  • Format the first partition with FAT32 file system:
root@compulab:~# mkfs.vfat -n boot /dev/mmcblk0p1
  • Format the second partition with EXT4 file system:
root@compulab:~# mkfs.ext4 /dev/mmcblk0p2
  • Mount both partitions:
root@compulab:~# mkdir -p /media/mmcblk0p1 && mount /dev/mmcblk0p1 /media/mmcblk0p1
root@compulab:~# mkdir -p /media/mmcblk0p2 && mount /dev/mmcblk0p2 /media/mmcblk0p2
  • Copy the zImage-cl-som-am57x and the am57xx-sbc-am57x.dtb to the first (FAT) partition:
root@compulab:~# cp /mount/point/zImage-cl-som-am57x /mount/point/am57xx-sbc-am57x.dtb /media/mmcblk0p1 && sync
  • Extract the content of the debian-armhf-image.tar.bz2 onto the second partition:
root@compulab:~# tar --numeric-owner -xvpjf /mount/point/debian-armhf-image.tar.bz2 -C /media/mmcblk0p2 && sync
  • Remove MMC/SD card from SB-SOM-AM57x MMC/SD card socket (if used for installation) and reboot the module:
root@compulab:~# reboot
Install on SATA drive
Admolition note.png The below procedure will work only on empty SATA drive. If you have already used the drive, please delete all the partitions before proceeding.
  • In this subsection the term /mount/point can be:
    • /mnt/net if NFS is used
    • /media/mmcblk1pX if an MMC/SD card is used, where X is the partition number.
    • /media/sdXY if USB storage is used, where X is the USB drive letter and Y is the partition number.
Admolition note.png In the below procedure the first (boot) partition can be either FAT32 or EXT2/3/4. The example below is only for FAT32 filesystem.
  • Identify SATA drive special device file
export SATA_DRIVE=/dev/`basename /sys/devices/platform/44000000.ocp/4a140000.sata/ata1/host0/target0\:0\:0/0\:0\:0\:0/block/sd?`
  • Create two partitions for the Linux kernel (FAT32 100M) and root file system (EXT4 the rest of the disk) on SATA drive:
root@compulab:~# echo -e "n\np\n1\n\n+100M\na\n1\nt\nc\nn\np\n2\n\n\nw\neof\n" | fdisk ${SATA_DRIVE}
  • Format the first partition with FAT32 file system:
root@compulab:~# mkfs.vfat -n boot ${SATA_DRIVE}1
  • Format the second partition with EXT4 file system:
root@compulab:~# mkfs.ext4 ${SATA_DRIVE}2
  • Mount both partitions:
root@compulab:~# mkdir -p /media/boot && mount ${SATA_DRIVE}1 /media/boot
root@compulab:~# mkdir -p /media/rootfs && mount ${SATA_DRIVE}2 /media/rootfs
  • Copy the zImage-cl-som-am57x and the am57xx-sbc-am57x.dtb to the first (FAT) partition:
root@compulab:~# cp /mount/point/zImage-cl-som-am57x /mount/point/am57xx-sbc-am57x.dtb /media/boot && sync
  • Extract the content of debian-armhf-image.tar.bz2 onto the second partition:
root@compulab:~# tar --numeric-owner -xvpjf /mount/point/debian-armhf-image.tar.bz2 -C /media/rootfs && sync
  • Reboot the module:
root@compulab:~# reboot

After Installation

Boot from eMMC

Default boot settings of CL-SOM-AM57x allows auto eMMC boot. If the boot settings are different than default, the following manual setup may be required.

  • Set the bootargs environment variable:
CL-SOM-AM57x # setenv bootargs "root=/dev/mmcblk0p2 rw rootwait console=ttyO2,115200n8"
  • To boot Linux, type:
CL-SOM-AM57x # setenv bootdelay 3
CL-SOM-AM57x # setenv bootcmd 'mmc dev 1 && mmc rescan && load mmc 1 ${loadaddr} zImage-cl-som-am57x && load mmc 1 ${fdtaddr}  am57xx-sbc-am57x.dtb && bootz ${loadaddr} - ${fdtaddr}''
CL-SOM-AM57x # saveenv
CL-SOM-AM57x # boot

Boot from SATA drive

  • Set the bootargs environment variable:
CL-SOM-AM57x # setenv bootargs "root=/dev/sda2 rootfstype=ext4 rw rootwait console=ttyO2"
  • To boot Linux, type:
CL-SOM-AM57x # setenv bootdelay 3
CL-SOM-AM57x # setenv bootcmd 'load scsi 0 ${loadaddr} zImage-cl-som-am57x && load scsi 0 ${fdtaddr} am57xx-sbc-am57x.dtb && bootz ${loadaddr} - ${fdtaddr}'
CL-SOM-AM57x # saveenv
CL-SOM-AM57x # boot

See also