The Juno Arm development board is an open, vendor-neutral, Armv8-A development platform. Add documentation that briefly outlines the hardware, and describes building and installation of U-Boot.
Signed-off-by: Andre Przywara andre.przywara@arm.com --- doc/board/armltd/index.rst | 1 + doc/board/armltd/juno.rst | 117 +++++++++++++++++++++++++++++++++++++ 2 files changed, 118 insertions(+) create mode 100644 doc/board/armltd/juno.rst
diff --git a/doc/board/armltd/index.rst b/doc/board/armltd/index.rst index caa6fd2bb0..68d938c647 100644 --- a/doc/board/armltd/index.rst +++ b/doc/board/armltd/index.rst @@ -8,3 +8,4 @@ ARM Ltd. boards and emulated systems :maxdepth: 2
fvp64 + juno diff --git a/doc/board/armltd/juno.rst b/doc/board/armltd/juno.rst new file mode 100644 index 0000000000..f37bc2c78e --- /dev/null +++ b/doc/board/armltd/juno.rst @@ -0,0 +1,117 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. Copyright (C) 2021 Arm Ltd. + +Arm Juno board +============== + +The `Juno development board`_ is an open, vendor-neutral, Armv8-A +development platform, made by Arm Ltd. It is based on the former Versatile +Express series. +There are three revisions of the board: + +* Juno r0, with two Cortex-A57 and four Cortex-A53 cores, without PCIe. +* Juno r1, with two Cortex-A57 and four Cortex-A53 cores, in later silicon + revisions, and with PCIe slots, Gigabit Ethernet and two SATA ports. +* Juno r2, with two Cortex-A72 and four Cortex-A53 cores, otherwise the + same as r1. + +Among other things, the motherboard contains a management controller (MCP), +an FPGA providing I/O interfaces (IOFPGA) and 64MB of NOR flash. The provided +platform devices resemble the VExpress peripherals. +The actual SoC also contains a Cortex-M3 based System Control Processor (SCP). + +U-Boot build +------------ +There is only one defconfig and one binary build that covers all three board +revisions, so to generate the needed ``u-boot.bin``: + +.. code-block:: bash + + $ make vexpress_aemv8a_juno_defconfig + $ make + +The automatic distro boot sequence looks for UEFI boot applications and +``boot.scr`` scripts on various boot media, starting with USB, then on disks +connected to the two SATA ports, PXE, DHCP and eventually on the NOR flash. + +U-Boot installation +------------------- +This assumes there is some firmware on the SD card or NOR flash (see below +for more details). The U-Boot binary is included in the Trusted Firmware +FIP image, so after building U-Boot, this needs to be repackaged or recompiled. + +The NOR flash will be updated by the MCP, based on the content of a micro-SD +card, which will be exported as a USB mass storage device via the rear USB-B +socket. So to access that SD card, connect a USB-A->USB-B cable between some +host computer and the board, and mount the FAT partition on the UMS device. +If there is no device, check the upper serial port for a prompt, and +explicitly enable the USB interface:: + + Cmd> usb_on + Enabling debug USB... + +Repackaging an existing FIP image +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +To prevent problems, it is probably a good idea to backup the existing firmware, +for instance by just copying the entire SOFTWARE directory beforehand. + +To just repackage with an updated U-Boot, first extract the current FIP image: + +.. code-block:: bash + + $ mkdir /tmp/juno; cd /tmp/juno + $ fiptool unpack /mnt/juno/SOFTWARE/fip.bin + +Then, re-assemble the FIP image, replacing the "``nt-fw``" component with +your newly compiled ``u-boot.bin``. To find the right command line, look at the +output of "``fiptool info``", then use the given command line option for each +file: + +.. code-block:: bash + + $ fiptool info /mnt/juno/SOFTWARE/fip.bin + $ fiptool create --scp-fw scp-fw.bin --soc-fw soc-fw.bin \ + --hw-config hw-config.bin ... --nt-fw /path/to/your/u-boot.bin fip.bin + $ cp fip.bin /mnt/juno/SOFTWARE/fip.bin + +Unmount the USB mass storage device and reboot the board, the new ``fip.bin`` +will be automatically written to the NOR flash and then used. + +Rebuilding Trusted Firmware +^^^^^^^^^^^^^^^^^^^^^^^^^^^ +You can also generate a new FIP image by compiling Arm Trusted Firmware, +and providing ``u-boot.bin`` as the BL33 file. For that you can either build +the required `SCP firmware`_ yourself, or just extract the existing +version from your ``fip.bin`` (as above): + +.. code-block:: bash + + $ mkdir /tmp/juno; cd /tmp/juno + $ fiptool unpack /mnt/juno/SOFTWARE/fip.bin + +Then build TF-A: + +.. code-block:: bash + + $ git clone https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git + $ cd trusted-firmware-a + $ make CROSS_COMPILE=aarch64-linux-gnu- PLAT=juno DEBUG=1 \ + SCP_BL2=/tmp/juno/scp-fw.bin BL33=/path/to/your/u-boot.bin fiptool all fip + $ cp build/juno/debug/bl1.bin build/juno/debug/fip.bin /mnt/juno/SOFTWARE + +Then umount the USB device, and reboot, as above. + +Device trees +------------ +The device tree files for the boards are maintained in the Linux kernel +repository. They end up in the root of the SD card, as ``juno.dtb``, +``juno-r1.dtb``, and ``juno-r2.dtb``, respectively. The MCP firmware will copy +the one matching the board revision into the NOR flash, into the ``board.dtb`` +partition. U-Boot picks its control DTB from there, you can pass this on to +a kernel using ``$fdtcontroladdr``. +You can update the DTBs anytime, by building them using the ``dtbs`` make +target from a Linux kernel tree, then just copying the generated binaries +to the SD card. + +.. _`Juno development board`: https://developer.arm.com/tools-and-software/development-boards/juno-develop... +.. _`SCP firmware`: https://github.com/ARM-software/SCP-firmware.git