board: motorola: add Atrix 4G MB860 and Droid X2 MB870 support
The Motorola Atrix 4G (MB860) and Droid X2 (MB870) both featured a
dual-core NVIDIA Tegra 2 AP20H processor clocked at 1GHz, coupled with 1GB
of DDR2 RAM. Storage consisted of 16GB of internal flash memory, expandable
via microSD. The display was a 4.0-inch TFT LCD with a resolution of
960x540 pixels (qHD). The devices originally ran on Android up to 2.3
(Gingerbread).
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
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+.. SPDX-License-Identifier: GPL-2.0+
+
+Motorola
+========
+
+.. toctree::
+ :maxdepth: 2
+
+ mot
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+.. SPDX-License-Identifier: GPL-2.0+
+
+U-Boot for the Motorola Atrix 4G (MB860) and Droid X2 (MB870)
+=============================================================
+
+``DISCLAMER!`` Moving your device to use U-Boot assumes replacement of the
+vendor bootloader. Vendor Android firmwares will no longer be able to run on
+the device. This replacement IS reversible if you have backups.
+
+Quick Start
+-----------
+
+- Prerequisites
+- Build U-Boot
+- Process U-Boot
+- Flashing U-Boot into the eMMC
+- Boot
+- Self Upgrading
+
+Prerequisites
+-------------
+
+In order to work with RCM/APX mode, both devices require a factory cable which
+is made by routing 5V to the ID pin of a micro-USB cable (5v is applied to both
+ID and dedicated 5v). This way, the host PC can detect the device in RCM mode,
+and the device can operate without a battery.
+
+Build U-Boot
+------------
+
+Device support is implemented by applying config fragment to a generic
+board defconfig. Valid fragments are ``daytona.config`` and ``olympus.config``.
+
+.. code-block:: bash
+
+ $ export CROSS_COMPILE=arm-none-eabi-
+ $ make mot_defconfig olympus.config # For Atrix 4G
+ $ make
+
+After the build succeeds, you will obtain the final ``u-boot-dtb-tegra.bin``
+image, ready for further processing.
+
+Process U-Boot
+--------------
+
+``DISCLAMER!`` All questions related to the re-crypt work should be asked
+in re-crypt repo issues. NOT HERE!
+
+re-crypt is a tool that processes the ``u-boot-dtb-tegra.bin`` binary into form
+usable by device. This process is required only on the first installation or to
+recover the device in case of a failed update. You need to know your device
+individual SBK to continue.
+
+.. code-block:: bash
+
+ $ git clone https://gitlab.com/grate-driver/re-crypt.git
+ $ cd re-crypt # place your u-boot-dtb-tegra.bin here
+ $ ./re-crypt.py --dev olympus --sbk <your sbk> --split
+
+where SBK has next form ``0xXXXXXXXX`` ``0xXXXXXXXX`` ``0xXXXXXXXX`` ``0xXXXXXXXX``
+
+The script will produce ``bct.img`` and ``ebt.img`` ready to flash.
+
+Flashing U-Boot into the eMMC
+-----------------------------
+
+``DISCLAMER!`` All questions related to fusee-tools should be asked in the proper
+place. NOT HERE! Flashing U-Boot will erase all eMMC, so make a backup before!
+
+U-Boot pre-loaded into RAM acts the same as when it was booted "cold". Currently
+U-Boot supports bootmenu entry fastboot, which allows to write a processed copy
+of U-Boot permanently into eMMC.
+
+While pre-loading U-Boot, hold the ``volume down`` button which will trigger
+the bootmenu. There, select ``fastboot`` using the volume and power buttons.
+After, on host PC, do:
+
+.. code-block:: bash
+
+ $ fastboot flash 0.1 bct.img
+ $ fastboot flash 0.2 ebt.img
+ $ fastboot reboot
+
+Device will reboot.
+
+Boot
+----
+
+To boot Linux, U-Boot will look for an ``extlinux.conf`` on MicroSD and then on
+eMMC. Additionally, if the Volume Down button is pressed while booting, the
+device will enter bootmenu. Bootmenu contains entries to mount MicroSD and eMMC
+as mass storage, fastboot, reboot, reboot RCM, poweroff, enter U-Boot console
+and update bootloader (check the next chapter).
+
+Flashing ``repart-block.bin`` eliminates vendor restrictions on eMMC and allows
+the user to use/partition it in any way the user desires.
+
+Self Upgrading
+--------------
+
+Place your ``u-boot-dtb-tegra.bin`` on the first partition of the MicroSD card
+and insert it into the device. Enter bootmenu, choose update the bootloader
+option with the Power button and U-Boot should update itself. Once the process
+is completed, U-Boot will ask to press any button to reboot.