NXP i.MX8MQ EVK Evaluation Board
================================

Board comes with:

* 3GiB of LPDDR4 RAM
* 16GiB eMMC

Not including booting via serial, the device can boot from either SD or eMMC.

Downloading DDR PHY and HDMI/eDP Firmware
-----------------------------------------

As a part of DDR intialization routine NXP i.MX8MQ 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

You will also need to copy the HDMITX controller firmware in order to
use the HDMI and/or eDP display output::

  for f in signed_dp_imx8m.bin \
	   signed_hdmi_imx8m.bin; \
  do \
	   cp firmware-imx-8.0/firmware/hdmi/cadence/${f} \
	      firmware/${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

Boot Configuration
==================

The NXP i.MX8MQ EVK Evaluation Board has two switches responsible for
configuring bootsource/boot mode:

 * SW802 for selecting appropriate BMOD
 * SW801 for selecting appropriate boot medium

In order to select internal boot set SW802 as follows::

  +-----+
  |     |
  | O | | <--- on = high level
  | | | |
  | | O | <--- off = low level
  |     |
  | 1 2 |
  +-----+

Bootsource is the internal eMMC::

  +---------+
  |         |
  | | | O | |
  | | | | | |  <---- eMMC
  | O O | O |
  |         |
  | 1 2 3 4 |
  +---------+

Bootsource is the SD2 slot::

  +---------+
  |         |
  | O O | | |
  | | | | | |  <---- SD2
  | | | O O |
  |         |
  | 1 2 3 4 |
  +---------+


Serial boot SW802 setting needed for i.MX8 DDR Tool is as follows::

  +-----+
  |     |
  | | O | <--- on = high level
  | | | |
  | O | | <--- off = low level
  |     |
  | 1 2 |
  +-----+
