uboot config requirement

To talk with uuu, uboot need enable fastboot. fastboot need auto run when detect boot from USB.

    CONFIG_CMD_FASTBOOT=y
    CONFIG_USB_FUNCTION_FASTBOOT=y
    CONFIG_USB_GADGET=y
    CONFIG_USB_GADGET_DOWNLOAD=y
    CONFIG_USB_GADGET_MANUFACTURER="FSL"
    CONFIG_USB_GADGET_VENDOR_NUM=0x0525
    CONFIG_USB_GADGET_PRODUCT_NUM=0xa4a5
    CONFIG_CI_UDC=y                           # UDC need change according system, some system use CONFIG_USB_DWC3, some use CONFIG_USB_CDNS3
    CONFIG_FSL_FASTBOOT=y
    CONFIG_FASTBOOT=y
    CONFIG_FASTBOOT_BUF_ADDR=0x83800000       # Address need change according system, generally it can be the same as ${LOADADDR}
    CONFIG_FASTBOOT_BUF_SIZE=0x40000000
    CONFIG_FASTBOOT_FLASH=y
    CONFIG_FASTBOOT_FLASH_MMC_DEV=1
    CONFIG_EFI_PARTITION=y
    CONFIG_ANDROID_BOOT_IMAGE=y

If use SPL, SDP need be enabled.

     CONFIG_SPL_USB_HOST_SUPPORT=y
     CONFIG_SPL_USB_GADGET_SUPPORT=y
     CONFIG_SPL_USB_SDP_SUPPORT=y
     CONFIG_SDP_LOADADDR=0x40400000           # Address need change according system, choose free memory

uuu related patches.

https://source.codeaurora.org/external/imx/uboot-imx/log/?h=imx_v2017.03_4.9.123_imx8mm_ga

About Fastboot enable:

     719651a MLK-18257-1 Enable fastboot support in qxp mek board
     d5226a3 MLK-18257-2: fix fastboot build warning
     219c989 MLK-18257-3 run fastboot if initramfs is in validate
     09b1876 MLK-18257-4 use another method check if need run bootcmd_mfg
     3b1fa9d MLK-18257-5 enhence fastboot uboot cmd
     ca96e0b MLK-18406 fastboot support all partition

About uboot SDP enable:

     192a26d MLK-18707-1: SDP: use CONFIG_SDP_LOADADDR as default load address
     9764fb2 MLK-18707-2 iMX8M enable fastboot as default
     db9a634 MLK-18862 imx8mm uuu can write emmc by fastboot

Additional environment need be define

Table 1. Table uuu environment

Variable	Usage	Description
emmc_dev	emmc burn	eMMC device number
sd_dev	burn sd	sd slot device number
kboot	boot kernel\burn nand	kernel boot command, it is booti for arm64, bootz for arm32
weim_uboot	burn weim nor	uboot burn to position of weim nor
weim_base	burn weim nor	weim base address
mtdparts	burn nand	NAND flash partition configuration, such as "mtdparts=8000000.nor:1m(boot),-(rootfs)\\;gpmi-nand:64m(nandboot),16m(nandkernel),16m(nanddtb),16m(nandtee),-(nandrootfs) "
spi_bus	burn spi (not qspi\fspi)	spi nor flash bus number
spi_uboot	burn spi (not qspi\fspi)	spi nor flash uboot offset