This commit adds a page for the newly added Variscite board. The information about downloading the NXP firmware blobs was obtained from NXP's public U-Boot sources for the i.MX processors [1]. [1] https://github.com/nxp-imx/uboot-imx Signed-off-by: Michael Kopfensteiner <michael.kopfensteiner@xxxxxxxxx> --- .../imx/variscite-dt8mcustomboard-imx8mp.rst | 149 ++++++++++++++++++ 1 file changed, 149 insertions(+) create mode 100644 Documentation/boards/imx/variscite-dt8mcustomboard-imx8mp.rst diff --git a/Documentation/boards/imx/variscite-dt8mcustomboard-imx8mp.rst b/Documentation/boards/imx/variscite-dt8mcustomboard-imx8mp.rst new file mode 100644 index 0000000000..0e986a1086 --- /dev/null +++ b/Documentation/boards/imx/variscite-dt8mcustomboard-imx8mp.rst @@ -0,0 +1,149 @@ +Variscite DT8MCustomBoard with DART-MX8M-PLUS SOM +================================================= + +This board is an eval-kit for the Variscite DART-MX8M-PLUS SOM. The latter is a +SOM based on the i.MX8M Plus processor. As seen in official Variscite documents there exist +several hardware revisions for this board. Currently only revision 3.0 could was tested +with Barebox. + +The Variscite DART-MX8M-PLUS SOM is available in different configurations. For a rough overview, +these are some of the possible options: + +* Processor: NXP i.MX8M Plus, either @1.6GHz or @1.8GHz +* 1 to 8 GiB LPDDR4 RAM +* 8 to 128 GiB eMMC +* (optional) GigE PHY on module +* (optional) Wifi + Bluetooth Chip on module + +Besides that the SOM offers a lot of interfaces. Among some of the interfaces that are +made available by the eval-board are: + +* USB3 +* GigE Ethernet +* PCIe +* SD-card slot +* HDMI + +More Information about the eval-board can be found at +https://www.variscite.com/product/single-board-computers/var-dt8mcustomboard/ + +More Information about the targeted SOM can be found at +https://www.variscite.com/product/system-on-module-som/cortex-a53-krait/dart-mx8m-plus-nxp-i-mx-8m-plus + +Providing necessary binary files +-------------------------------- + +Barebox requires some blobs to successfully bringup the system. These blobs +serve different use cases. Barebox's build system will look for these files +in the configured firmware directory (``firmware`` by default). The build +systems expects these files to have certain names. + +Hence the very first thing before building Barebox is to obtain these files and +placing them in the firmware folder. + +The DDR4 training files are part of a set of files that is provided by NXP. +They are provided under the terms of a proprietary EULA one has to agree to, +before getting access to the blobs. They are provided as self-extracting +archive. To get a hand on them, perform the following:: + + $ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.10.bin + $ chmod u+x firmware-imx-8.10.bin + $ ./firmware-imx-8.10.bin + +Assuming that the downloaded executable was run from inside the toplevel directory of the Barebox repo, +the necessary DDR4 training files can simply be hardlinked (or copied):: + + $ ln firmware-imx-8.10/firmware/ddr/synopsys/lpddr4_pmu_train_1d_dmem_202006.bin firmware/lpddr4_pmu_train_1d_dmem.bin + $ ln firmware-imx-8.10/firmware/ddr/synopsys/lpddr4_pmu_train_1d_imem_202006.bin firmware/lpddr4_pmu_train_1d_imem.bin + $ ln firmware-imx-8.10/firmware/ddr/synopsys/lpddr4_pmu_train_2d_dmem_202006.bin firmware/lpddr4_pmu_train_2d_dmem.bin + $ ln firmware-imx-8.10/firmware/ddr/synopsys/lpddr4_pmu_train_2d_imem_202006.bin firmware/lpddr4_pmu_train_2d_imem.bin + +Another required binary is the Secure Monitor Firmware (BL31). This is build by some ARM Trusted Firmware project (ATF). +One fork is provided by NXP and can be downloaded from https://github.com/nxp-imx/imx-atf. Variscite does maintain it's +own fork of NXP's ATF project. This can be found at https://github.com/varigit/imx-atf/. + +Once the ATF has been built successfully, the resulting BL31 binary needs to be placed in the ``firmware`` directory +under the filename ``imx8mp-bl31.bin``. + +After those files are in place, one can proceed with the usual Barebox build routine. + +Compiling Barebox +----------------- + +A quick way to configure and compile Barebox for this board is by starting from +the `imx_v8_defconfig`:: + + export ARCH=arm + export CROSS_COMPILE=/path/to/your/toolchain/bin/aarch64-v8a-linux-gnu- + make imx_v8_defconfig + make + +With this procedure one might need some additional firmware files in place to +successfully build the Barebox images for all selected boards. A solution to this is +either to copy the necessary files to the `firmware` directory or simply run +`make menuconfig` and deselect the unwanted boards under "System Type". + +When the build succeeds, the Barebox image `barebox-variscite-imx8mp-dart-cb.img` +can be found in the `images` subdirectory. + +Boot Configuration +------------------ + +The DT8MCustomBoard allows the user to choose whether to proceed with the *internal* +or *external boot mode*. With this board, *internal boot mode* refers to booting +from the eMMC memory, while *external boot mode* refers to booting from an SD-card. + +The mode is selected with switch SW7, located below the buttons on the board. + +Set the switch to **ON** for the BootROM to perform an *internal boot*. Otherwise +set the switch to **OFF** to follow the *external boot* procedure. + +If in doubt, refer to the silk screen on the board, to select the correct switch +position. + +If the BootROM cannot find a valid bootloader image in the selected source, +it'll try several fallbacks until it finally ends in USB download mode or finds +a valid bootloader image to load. + +To load an image when the board is in USB download mode the imx-usb-loader tool +is required. To build this tool alongside the Barebox image, select it in the +config menu under "Host Tools". + +Starting Barebox +---------------- + +An easy solution to start Barebox bare metal is to use the *external boot* mode and +copy Barebox onto a SD-card. + +To copy the Barebox binary onto a SD-card, use the `dd` tool on linux:: + + dd if=images/barebox-variscite-imx8mp-dart-cb.img of=/dev/mmcblk0 bs=512 seek=1 skip=1 + +Next, you insert the SD-card into the eval board and select *external boot mode* on +switch SW7. + +When you power up the board, you should now see Barebox's output appearing on your +serial console. + +Currently Supported Features +---------------------------- + +The Barebox binary configured by the `variscite_imx8mp_dart_cb_defconfig` does currently +not support all possible features of the DT8MCustomBoard. Yet the binary does contain +everything necessary to boot an operating system on the i.MX8MP. + +Some of the currently supported features: + +* general i.MX8MP bringup, including DRAM initialisation +* working eMMC and SD-card support +* serial console on UART 1 - available through the micro-USB connector on the board +* working gigabit ethernet on the first port (labeled ETH, named `eth0` in Barebox and linux) +* working LED and GPIO support + +Some functionality that is currently missing or untested: + +* secondary ethernet interface (labeled ETH2) will currently not work +* secure boot (not tested) +* framebuffer support (missing driver) +* OP-TEE integration (not tested - early loading currently not supported by the startup code) +* running on other hardware revisions of the DT8MCustomBoard than v3.0 (not tested) \ No newline at end of file -- 2.30.2
