1NXP i.MX 8M Series 2================== 3 4The i.MX 8M family of applications processors based on Arm Corte-A53 and Cortex-M4 5cores provide high-performance computing, power efficiency, enhanced system 6reliability and embedded security needed to drive the growth of fast-growing 7edge node computing, streaming multimedia, and machine learning applications. 8 9Boot Sequence 10------------- 11 12Bootrom --> SPL --> BL31 --> BL33(u-boot) --> Linux kernel 13 14How to build 15------------ 16 17Build Procedure 18~~~~~~~~~~~~~~~ 19 20- Prepare AARCH64 toolchain. 21 22- Build spl and u-boot firstly, and get binary images: u-boot-spl.bin, 23 u-boot-nodtb.bin and dtb for the target board. 24 25- Build TF-A 26 27 Build bl31: 28 29 .. code:: shell 30 31 CROSS_COMPILE=aarch64-linux-gnu- make PLAT=<Target_SoC> bl31 32 33 Target_SoC should be "imx8mq" for i.MX8MQ SoC. 34 Target_SoC should be "imx8mm" for i.MX8MM SoC. 35 Target_SoC should be "imx8mn" for i.MX8MN SoC. 36 Target_SoC should be "imx8mp" for i.MX8MP SoC. 37 38Deploy TF-A Images 39~~~~~~~~~~~~~~~~~~ 40 41TF-A binary(bl31.bin), u-boot-spl.bin u-boot-nodtb.bin and dtb are combined 42together to generate a binary file called flash.bin, the imx-mkimage tool is 43used to generate flash.bin, and flash.bin needs to be flashed into SD card 44with certain offset for BOOT ROM. the u-boot and imx-mkimage will be upstreamed 45soon, this doc will be updated once they are ready, and the link will be posted. 46 47TBBR Boot Sequence 48------------------ 49 50When setting NEED_BL2=1 on imx8mm. We support an alternative way of 51boot sequence to support TBBR. 52 53Bootrom --> SPL --> BL2 --> BL31 --> BL33(u-boot with UEFI) --> grub 54 55This helps us to fulfill the SystemReady EBBR standard. 56BL2 will be in the FIT image and SPL will verify it. 57All of the BL3x will be put in the FIP image. BL2 will verify them. 58In U-boot we turn on the UEFI secure boot features so it can verify 59grub. And we use grub to verify linux kernel. 60