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diff --git a/Documentation/boards/imx/nxp-imx8mm-evk.rst b/Documentation/boards/imx/nxp-imx8mm-evk.rst new file mode 100644 index 0000000000..aa70419139 --- /dev/null +++ b/Documentation/boards/imx/nxp-imx8mm-evk.rst @@ -0,0 +1,100 @@ +NXP i.MX8MM EVK Evaluation Board +================================ + +Board comes with: + +* 2GiB of LPDDR4 RAM +* 16GiB eMMC + +Not including booting via serial, the device can boot from either SD or eMMC. + +Downloading DDR PHY Firmware +---------------------------- + +As a part of DDR intialization routine NXP i.MX8MM 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-8.0.bin + chmod +x firmware-imx-8.0.bin + ./firmware-imx-8.0.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 + +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-8.0/firmware/ddr/synopsys/${f} \ + firmware/${f}; \ + done + +DDR Configuration Code +====================== + +The following two files: + + - arch/arm/boards/nxp-imx8mq-evk/ddr_init.c + - arch/arm/boards/nxp-imx8mq-evk/ddrphy_train.c + +were obtained by running i.MX 8M DDR Tool that can be found here: + +https://community.nxp.com/docs/DOC-340179 + +Only minimal amount of necessary changes were made to those files. +All of the "impedance matching" code is located in "ddr.h". + +Build barebox +============= + + make imx_v8_defconfig + make + +Start barebox +============= + +The resulting image file is images/barebox-nxp-imx8mm-evk.img. Configure the +board for serial download mode as printed on the PCB. You can start barebox with +the imx-usb-loader tool that comes with barebox like this: + +./scripts/imx/imx-usb-loader images/barebox-nxp-imx8mm-evk.img + +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 following steps are required to write the image to the QSPI NOR flash: + + - The 32KiB preamble MMC preamble must be stripped. + + - 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. |