CM-T3517: Linux: Getting started

Preparation steps

• Obtain a PC workstation with a serial communication 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 CM-T3517 (link below).
• Download the Linux package for CM-T3517 from CompuLab website. Unzip the package to a directory on your host workstation.
• If MMC/SD card is used for booting into U-Boot, it must be prepared as described in CM-T3x: Linux: Booting from MMC/SD card article.
• All image files mentioned below can be found in images subdirectory

Image installation

• Connect the host PC to the SB-T35 base-board (connector P12) via the serial 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 CM-T3517 evaluation system. The U-Boot boot-loader will start and you will get a command prompt.

If the boot settings of your CM-T3517 are different than default, you may need to press and hold ^C while turning the CM-T3517 on, in order to get command prompt.

Installation using MMC/SD card

• Copy debian-image.ubi, uImage-cm-t3517, kernel.img, ramdisk.img and bootscr.img from Linux package for CM-T3517 to the root directory of the MMC/SD card.
• Insert the MMC/SD card into the SD socket (P13) on SB-T35.
• Use the following U-boot commands to boot Linux on CM-T3517:

> mmc init
> fatload mmc 0:1 80400000 bootscr.img
> source 80400000

• After the ramdisk image is loaded, you will get Linux login prompt. Login as root into the system.
• The MMC/CD card will be mounted automatically under /media/mmcblk0p1
• Format the NAND flash kernel partition and write the kernel image onto it:

$ flash_eraseall /dev/mtd3
$ nandwrite -p /dev/mtd3 /media/mmcblk0p1/uImage-cm-t3517

• Format the NAND flash root filesystem partition and write Debian filesystem image onto it:

$ ubiformat -O 2048 /dev/mtd4 -f /media/mmcblk0p1/debian-image.ubi

• Continue to After Installation section

Installation using NFS

• Connect the CM-T3517 Ethernet port (connector P18 on SB-T35) to your local network
• Copy debian-image.ubi and uImage-cm-t3517 from Linux package for CM-T3517 to a directory exported through NFS.
• Make sure that Linux kernel binary image kernel.img, ramdisk image ramdisk.img and bootloader script image bootscr.img are accessible by the TFTP server.

  - On Windows machine: copy kernel.img, ramdisk.img and bootscr.img to the same folder and point the TFTP server to that folder

  - On Linux machine: copy kernel.img, ramdisk.img and bootscr.img to TFTP server root directory, usually /tftpboot or /tftproot.

• You can use U-boot dhcp command to obtain IP address or manually set ipaddr environment variable:

> setenv ipaddr <CM-T3517 ip address>

• Set serverip environment variable and save the new environment to NAND flash:

> setenv serverip <host ip address>
> saveenv

• Use the following U-boot command to boot Linux on CM-T3517:

> tftp 80400000 bootscr.img && source 80400000

• After the ramdisk image is loaded you will get Linux login prompt. Login as root into the system.
• Obtain the IP address for CM-T3517:
  • Using DHCP:

    $ ifup `basename /sys/devices/platform/davinci_emac/net/eth?`

  • If you do not have DHCP server, you can set a static IP address using ifconfig:

    $ ifconfig `basename /sys/devices/platform/davinci_emac/net/eth?` <ip address>

• Mount the NFS share containing uImage-cm-t3517 and debian-image.ubi image:

$ mount -n <host ip>:/path/to/nfs/share /mnt/net

• Format the NAND flash kernel partition and write the kernel image onto it:

$ flash_eraseall /dev/mtd3
$ nandwrite -p /dev/mtd3 /mnt/net/uImage-cm-t3517

• Format the NAND flash root filesystem partition and write Debian filesystem image onto it:

$ ubiformat -O 2048 /dev/mtd4 -f /mnt/net/debian-image.ubi

• Continue to After Installation section

After Installation

• Make sure there is no MMC/SD card in the SD socket (P13) on SB-T35.
• Reset the system.

If the boot settings of your CM-T3517 are different than default, you may need to press and hold ^C while turning the CM-T3517 on, in order to get command prompt.

• To boot Linux, type:

> nboot 82000000 nand0 2a0000; bootm

The Linux kernel for CM-T3517 is shipped with built-in command line parameters that define primary console, default display settings, root device and root filesystem type. Setting U-Boot bootargs environment variable overrides default kernel command line!

• For Linux automatic boot, type:

> setenv bootdelay 3
> setenv bootcmd "nboot 82000000 nand0 2a0000; bootm"
> saveenv
> boot

If you want to get back to U-Boot prompt, hold Ctrl-C during reset.

CM-T3517 will boot Debian Linux from the internal NAND flash.

See also

• CM-T3517: Linux: Debian
• CM-T3517: Linux: Kernel
• Linux Development for ARM modules
• U-Boot for CM-T3517