Getting Started with ROACH

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Your ROACH boards ship with all devices already programmed. However, there are some aspects of the device you may wish to customise before deployment.

Contents

Shipping Defaults

ROACH ships with the FLASH memory containing uBoot (a simple bootloader including some ROACH-specific commands), a custom Linux kernel for the PPC and a stripped-down Linux root filesystem called Busybox.

  • X-port IP Address: 192.168.4.20
  • PPC Ethernet port IP address (uBoot): not configured.
  • PPC Ethernet port IP address (busybox): not configured. Use busybox ifconfig eth0 ... to configure.
  • PPC Ethernet port IP address (debian etch off USB): not configured
  • PPC Ethernet port IP address (debian etch off network boot): DHCP
  • PPC Ethernet port MAC address: Software reconfigurable, defaults to 02:00:00:xx:yy:zz where xxyyzz is the serial number of the board.
  • Hostname under linux: not set. Defaults to any supplied DHCP option.

To change the IP address of the X-port, connect to its web interface and use the supplied GUI. There is also a telnet server on port 10001.

The MAC address of the PPC 1GbE port can be changed in uBoot with the command setenv ethaddr xx:xx:xx:xx:xx:xx. Any changes are volatile and requires a saveenv command to store them on flash.

The front panel

There are two switches and two LEDs on the front panel.

  • Pressing the power switch briefly will power the board on. Hold it down for ~7 seconds to power off.
  • Pressing the reset switch performs a hard reset. By default, the board will remain in the powered-off state after a hard reset. This behaviour can be changed by setting a bit of the SYS_CTRL register on the Fusion. See documentation on the ROACH Monitor for further information.
  • The green LED indicates power.
    • Off indicates no power at all.
    • Flashing indicates AC power is present, but the board is powered down.
    • Constant on indicates that the board is powered up.
  • The red LED indicates an error condition.
    • Off indicates nominal operation (no error).
    • On indicates a warning threshold has been exceeded (temperature or voltage). The board will continue to operate under this condition.
    • Flashing indicates that the board automatically powered down due to an error. Either a voltage rail or temperature was overrange.

The boot procedure

You can watch the boot procedure by connecting a serial port configured for 115200,N,8.

The PowerPC loads uBoot, checks memory and network. Unless you press a key to interrupt the boot process (over the serial port), it will load Linux. The kernel's default boot parameters will load Busybox from flash. With no additional hardware, you can use Busybox by logging in as "root", with no password.

How do I soft-reboot the board?

  • From uBoot: restart
  • From Busybox: busybox reboot -f
  • From supplied Linux: reboot or shutdown -r now

Adding your own Linux filesystem

The preferred filesystem is based on Debian Etch. It is over 200MB when unzipped and does not fit on the onboard flash, so you will need to host it on a network share or on an external drive.

USB stick

Download this file.

This filesystem should be placed on either a USB drive or a MMC/SD card; see below for more information on getting the SD/MMC interface running.

Unzip it and place it on an ext2 formatted USB stick. It must be the first partition on the USB stick. Plug it into ROACH and turn on. You will need a serial cable connected to interrupt the standard boot process and altering the default boot process. Press any key when prompted to interrupt booting from flash, and type

run usbboot

This will boot the Linux kernel from onboard flash, but attempt to mount /dev/sda1 as your root filesystem. The default is to mount the filesystem read only. If you want read/write, at the uboot prompt, type

setenv usbboot setenv bootargs console=ttyS0,115200 mtdparts=\$\{partitions\} rootdelay=8 root='/dev/sda1 rw'\; bootm 0xfc000000

These changes are volatile. ROACH will only boot this one time off USB, next time it will again default to booting off onboard flash after the usual 10 second timeout, unless you alter you environment variables...

How do I save the changes?

To change the default boot action change the 'bootcmd' environment variable:

setenv bootcmd run usbboot

Then save the changes to non-volatile flash:

saveenv

To permanently allow the filesystem to be mounted read/write, in /etc/rcSimple change the line:

mount -n -o remount, ro, noatime /

to:

mount -n -o remount, rw, noatime /

What if mount fails?

If the boot sequence fails to mount the usb stick's first partition, it will dump you into a shell on a read-only filesystem. This means that something is broken, and you should fix it. But as an interim solution, you can manually mount and pivot_root to the usb stick.

mount /dev/sda1 /mnt/disk
mount -o loop /mnt/disk/roach /mnt/loop
pivot_root /mnt/loop /mnt/loop/mnt/pivot
PATH=$PATH:/mnt/pivot/sbin:/mnt/pivot/bin
umount /mnt/pivot/proc
mount -t proc proc /proc

SD/MMC boot

The ROACH flash slot accepts Secure-Digital (SD) and Multimedia Memory Cards (MMC) cards upside-down.

The first-generation of ROACH boards' firmware does not include a controller for this card that is accessible from the PPC. Kernel support is also required. As such, the CPLD requires a reflash and U-boot and the kernel need to be updated before the SD/MMC slot can be used. You will need a standard Xilinx JTAG programmer for this. See Enabling the MMC card slot for details on how to get the SD/MMC card slot up and running.

The filesystem must be placed in the first partition on the card, formatted as ext2, as outlined above for the USB boot method.

Once the MMC interface is configured, you can boot from the MMC via the command:

run mmcboot

There is no DMA on the SD/MMC interface. The CPU polls the CPLD, resulting in higher CPU usage and lower performace. Expect read speeds of about 4MB/s and write speeds of just under 1.9MB/s. We recommend that you set noatime to your mount options to improve read/write performance.

NFS Boot

ROACH can boot off a network. This is useful if you have lots of ROACH boards and only want to maintain one kernel/filesystem. uBoot can pull all the necessary parameters from DHCP. You will need to preconfigure a server on the network to supply a root filesystem as well as a suitable kernel (not covered here). You can download a suitable Debian Etch filesystem here and the kernel here. Your local DHCP server should then provide the locations of these services to the ROACH board. More information can be found in the ROACH NFS guide.

uBoot commands

When ROACH boots, interrupt it at the uBoot prompt. Run the script called netboot:

run netboot

This will obtain the necessary boot information and boot Linux by executing the following three uBoot commands sequentially:

dhcp
setenv bootargs console=ttyS0,115200 root=${rootpath}$ ip=dhcp
boot

If your ROACH does not have this command (netboot), either run the aforementioned commands manually, or reset your environment settings back to default using the clearenv command to recover it. Bear in mind that this will erase your uboot settings, including erasing your preset MAC address. You will need to reenter this using setenv ethaddr xx:xx:xx:xx:xx:xx (MAC address suggestion: 02:00:00:serial_number) in order to get the network working.

These settings are volatile. Next time ROACH reboots, it will again boot off the onboard FLASH device, unless you save the changes...

How do I save the changes?

To change the default boot action change the 'bootcmd' environment variable:

setenv bootcmd run netboot


Then save the changes to non-volatile flash:

saveenv

What do all the board-mounted LEDs mean and what are all the connectors, jumpers and DIP switches for?

The LEDs are all soft-function, and their functions are thus not labelled on the board. The DIP switches are also soft function and by default will change some boot parameters. They should all be off by default.

For further information, see this document: ROACH configuration memo (KAT-7 DBE internal memo 008)

How do I talk to my ROACH over the network?

KATCP is the preferred communication protocol for talking to your applications over the network. This allows you to remotely program the FPGA with your bitstreams and control onboard registers, brams and network interfaces.

If you want to perform housekeeping functions (remote powerup or health monitoring like temperatures, fan speeds and voltage rails) take a look at the roach_monitor.py Python script.

How do I update the firmware and software on my ROACH?

You can update your onboard flash without any special hardware using your existing uBoot. This will allow you to update uBoot itself, the onboard Linux kernel and Busybox filesystem. There are precompiled binaries of this software available here. See the guide on this wiki, here, for detailed instructions.

The CPLD and Actel Fusion parts can only be updated using JTAG chains, which will require suitable programmers. This is beyond the scope of this guide. See ROACH_Bringup for further info.

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