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diff --git a/Documentation/boards/imx/nxp-imx8mn-evk.rst b/Documentation/boards/imx/nxp-imx8mn-evk.rst new file mode 100644 index 0000000000..597db57eaf --- /dev/null +++ b/Documentation/boards/imx/nxp-imx8mn-evk.rst @@ -0,0 +1,96 @@ +NXP i.MX8MN EVK Evaluation Board +================================ + +Board comes with either: + +* 2GiB of LPDDR4 RAM +* 2GiB of DDR4 RAM + +barebox supports both variants with the same image. + +Downloading DDR PHY Firmware +---------------------------- + +As a part of DDR intialization routine NXP i.MX8MN EVK requires and +uses several binary firmware blobs that are distributed under a +separate EULA and cannot be included in Barebox. In order to obtain +them do the following:: + + wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.12.bin + chmod +x firmware-imx-8.12.bin + ./firmware-imx-8.12.bin + +Executing that file should produce a EULA acceptance dialog as well as +result in the following files: + +- lpddr4_pmu_train_1d_dmem.bin +- lpddr4_pmu_train_1d_imem.bin +- lpddr4_pmu_train_2d_dmem.bin +- lpddr4_pmu_train_2d_imem.bin +- ddr4_dmem_1d_201810.bin +- ddr4_imem_1d_201810.bin +- ddr4_dmem_2d_201810.bin +- ddr4_imem_2d_201810.bin + +As a last step of this process those files need to be placed in +"firmware/":: + + for f in lpddr4_pmu_train_1d_dmem.bin \ + lpddr4_pmu_train_1d_imem.bin \ + lpddr4_pmu_train_2d_dmem.bin \ + lpddr4_pmu_train_2d_imem.bin; \ + do \ + cp firmware-imx-8.12/firmware/ddr/synopsys/${f} \ + firmware/${f}; \ + done + + for f in ddr4_dmem_1d_201810.bin \ + ddr4_imem_1d_201810.bin \ + ddr4_dmem_2d_201810.bin \ + ddr4_imem_2d_201810.bin; \ + do \ + cp firmware-imx-8.12/firmware/ddr/synopsys/${f} \ + firmware/${f%_201810.bin}.bin; \ + done + +Build barebox +============= + + make imx_v8_defconfig + make + +Installing barebox +================== + +When the EVK is strapped to boot from eMMC, the i.MX8M bootrom will +consult the eMMC ext_csd register to determine whether to boot +from the active eMMC boot partition or from the user area. + +The same barebox image written to the start of the SD-Card can +be written to the start of the eMMC user area. Power-fail-safe +installation to the eMMC boot partition requires special handling: + + - The barebox image must be written to the inactive boot partition, + then afterwards, the newly written boot partition is activated + (This is controlled by the barebox ``mmcX.boot`` variable). + + - The barebox image includes a 32KiB preamble that allows the image + to be directly writable to the start of the SD-Card or eMMC user area. + Unlike older i.MX8M, the i.MX8MN BootROM expects the bootloader to not + start at an offset when booting from eMMC boot partitions, thus the first + 32KiB must be stripped. + +The following steps are required to write the image to the QSPI NOR flash: + + - Strip the 32KiB preamble, like it is done for the eMMC boot partition case + (see above). + + - The QSPI NOR partition ``barebox`` must be erased before the stripped + image is written. The erase size depends on the stripped image size but + always start at offset 0. + + - Write the stripped barebox image to the QSPI NOR partition ``barebox`` + at offset 0. + +The ``barebox_update`` command takes care of this and need just be +supplied a barebox image as argument. |