BlueField Rshim Host Driver

The rshim driver provides a way to access the rshim resources on the BlueField target from external host machine. The current version implements virtual console and virtual network interface over rshim. It also provides rshim register access and some tools to manage the target, such as doing soft-reset, etc.

*) Source Code

The source code can be found under <BF_INSTALL>/src/drivers/rshim, where BF_INSTALL is the installation location of the BlueField release tarball.

*) Build & Install

Need to be root to install the driver

cd <BF_INSTALL>/src/drivers/rshim/ make -C /lib/modules/uname -r/build M=$PWD make -C /lib/modules/uname -r/build M=$PWD INSTALL_MOD_DIR=extra/rshim modules_install

The following kernel modules will be installed:

Common modules: rshim.ko rshim common code including console support rshim_net.ko rshim network driver

Different Backends: rshim_usb.ko rshim USB backend rshim_pcie.ko rshim PCIe backend with firmware burnt rshim_pcie_lf.ko rshim PCIe backend in livefish mode

*) Device Files

Each rshim backend will create a directory /dev/rshim/ with the following files. '' is the device id, which could be 0, 1, etc.

• /dev/rshim/boot Boot device file used to send boot stream to the ARM side, for example, cat install.bfb > /dev/rshim/boot

• /dev/rshim/console Console device, which can be used by console tools to connect to the ARM side, such as "screen /dev/rshim/console".

• /dev/rshim/rshim Device file used to access rshim register space. When reading / writing to this file, encode the offset as "((rshim_channel << 16) | register_offset)".

• /dev/rshim/misc: Key/Value pairs used to read/write misc information. For example,

  Dump the content.

  cat /dev/rshim/misc BOOT_MODE 1 # eMMC boot mode # 0: boot from USB/PCIe, 1: boot from eMMC SW_RESET 0 # Set to 1 to initiate SW RESET DRV_NAME rshim_usb # Backend driver name (display-only)

  Initiate a SW reset.

  It'll depend on the 'BOOT_MODE' to boot from USB/PCIe or eMMC.

  echo "SW_RESET 1" > /dev/rshim/misc

*) What if both USB and PCIe access are enabled

When both USB and PCIe are enabled, the related kernel modules rshim_usb.ko and rshim_pcie.ko will be loaded automatically. By default, the driver will pick one to access rshim depending on which one is detected first.

/etc/modprobe.d/rshim.conf can be used to specify which rshim driver to use, which will disable the 'auto-select' behavior.

 # /etc/modprobe.d/rshim.conf
 #
 # Uncomment the 'options' line below to specify a driver to use (rshim_usb,
 # rshim_pcie, or rshim_pcie_lf). If not specified, the first available one
 # will be selected by default.
 #
 # options rshim backend_driver=rshim_usb

*) Multiple Boards Support

Multiple boards could connect to the same host machine. Each of them has its own device directory /dev/rshim. Below are some guidelines how to set up rshim networking properly in such case.

• Each target should load only one backend (usb, pcie or pcie_lf).

• The host rshim network interface should have different MAC address and IP address, which can be configured with ifconfig like below or save it in configuration. ifconfig tmfifo_net0 192.168.100.2/24 hw ether 02:02:02:02:02:02

• The ARM side tmfifo interface should have unique MAC and IP as well, which can be done in the console.

*) How to change the MAC address of the ARM side permanently

• Login into Linux from the ARM console;
• mount -t efivarfs none /sys/firmware/efi/efivars
• chattr -i /sys/firmware/efi/efivars/RshimMacAddr-8be4df61-93ca-11d2-aa0d-00e098032b8c
• printf "\x07\x00\x00\x00\x00\x1a\xca\xff\xff\x03" >
  /sys/firmware/efi/efivars/RshimMacAddr-8be4df61-93ca-11d2-aa0d-00e098032b8c

The above 'printf' command set the MAC address to 00:1a:ca:ff:ff:03 (the last six bytes of the printf value).