U-Boot for the Toradex Verdin iMX8M Mini Module

Quick Start
===========

- Build the ARM trusted firmware binary
- Get the DDR firmware
- Build U-Boot
- Flash to eMMC
- Boot

Get and Build the ARM Trusted Firmware (Trusted Firmware A)
===========================================================

$ echo "Downloading and building TF-A..."
$ git clone -b imx_4.14.98_2.3.0 https://source.codeaurora.org/external/imx/imx-atf
$ cd imx-atf

Please edit `plat/imx/imx8mm/include/platform_def.h` so it contains proper
values for UART configuration and BL31 base address (correct values listed
below):
#define BL31_BASE		0x910000
#define IMX_BOOT_UART_BASE	0x30860000
#define DEBUG_CONSOLE		1

Then build ATF (TF-A):
$ make PLAT=imx8mm bl31

Get the DDR Firmware
====================

$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.4.1.bin
$ chmod +x firmware-imx-8.4.1.bin
$ ./firmware-imx-8.4.1.bin
$ cp firmware-imx-8.4.1/firmware/ddr/synopsys/lpddr4*.bin ./

Build U-Boot
============

$ export CROSS_COMPILE=aarch64-linux-gnu-
$ make verdin-imx8mm_defconfig
$ make flash.bin

Flash to eMMC
=============

> tftpboot ${loadaddr} flash.bin
> setexpr blkcnt ${filesize} + 0x1ff && setexpr blkcnt ${blkcnt} / 0x200
> mmc dev 0 1 && mmc write ${loadaddr} 0x2 ${blkcnt}

As a convenience, instead of the last two commands one may also use the update
U-Boot wrapper:
> run update_uboot

Boot
====

ATF, U-boot proper and u-boot.dtb images are packed into FIT image,
which is loaded and parsed by SPL.

Boot sequence is:
SPL ---> ATF (TF-A) ---> U-boot proper

Output:
U-Boot SPL 2020.01-00187-gd411d164e5 (Jan 26 2020 - 04:47:26 +0100)
Normal Boot
Trying to boot from MMC1
NOTICE:  Configuring TZASC380
NOTICE:  RDC off
NOTICE:  BL31: v2.0(release):rel_imx_4.14.98_2.3.0-0-g09c5cc994-dirty
NOTICE:  BL31: Built : 01:11:41, Jan 25 2020
NOTICE:  sip svc init


U-Boot 2020.01-00187-gd411d164e5 (Jan 26 2020 - 04:47:26 +0100)

CPU:   Freescale i.MX8MMQ rev1.0 at 0 MHz
Reset cause: POR
DRAM:  2 GiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... OK
In:    serial
Out:   serial
Err:   serial
Model: Toradex Verdin iMX8M Mini Quad 2GB Wi-Fi / BT IT V1.0A, Serial# 06535149
Net:   eth0: ethernet@30be0000
Hit any key to stop autoboot:  0
Verdin iMX8MM #