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 | 114 +++++++++++++++++++++++++++++++++++++ 2 files changed, 115 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..3d20ff129c --- /dev/null +++ b/doc/board/armltd/juno.rst @@ -0,0 +1,114 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. Copyright (C) 2021 Arm Ltd. + +Arm Juno development platform +============================= + +The `Juno development board`_ is an open, vendor-neutral, Armv8-A development +platform, made by Arm Ltd. It is part of the Versatile Express family. +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 (MCC), +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). +The `V2M-Juno TRM`_ contains more technical details. + +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 MCC, based on the content of a micro-SD +card, which is exported as a USB mass storage device via the rear USB-B +socket. So to access that SD card, connect a cable to some host computer, and +mount the FAT16 partition of 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, or at least +the current ``fip.bin``, beforehand. + +To just replace the BL33 image in the exising FIP image, you can use +`fiptool`_ from the Trusted Firmware repository, on the image file: + +.. code-block:: bash + + $ git clone https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git + $ cd trusted-firmware-a + $ make fiptool + $ tools/fiptool/fiptool update --nt-fw=/path/to/your/u-boot.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``, using `fiptool`_ (see 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 ``SOFTWARE/`` directory of the SD card, as +``juno.dtb``, ``juno-r1.dtb``, and ``juno-r2.dtb``, respectively. The MCC +firmware will look into the images.txt file matching the board revision, from +the ``SITE1/`` directory. Each version there will reference its respective DTB +file in ``SOFTWARE/``, and so the correct version will end in the NOR flash, in +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 ``SOFTWARE/`` directory of the SD card. + +.. _`Juno development board`: https://developer.arm.com/tools-and-software/development-boards/juno-develop... +.. _`V2M-Juno TRM`: https://developer.arm.com/documentation/100113/latest +.. _`fiptool`: https://github.com/ARM-software/arm-trusted-firmware/tree/master/tools/fipto... +.. _`SCP firmware`: https://github.com/ARM-software/SCP-firmware.git