Merge branch 'picasso' of https://source.denx.de/u-boot/custodians/u-boot-tegra

Branch contains bringup of Acer Iconia Tab A500 (codename picasso), a
Tegra 2 Android device with decent Linux kernel support. Ondevice tests
and U-Boot test suit all passed.

3 files changed, 135 insertions, 0 deletions

diff --git a/doc/board/acer/index.rst b/doc/board/acer/index.rst
new file mode 100644
index 00000000000..3741a700ccd
--- /dev/null
+++ b/doc/board/acer/index.rst
@@ -0,0 +1,9 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+ACER
+====
+
+.. toctree::
+   :maxdepth: 2
+
+   picasso
diff --git a/doc/board/acer/picasso.rst b/doc/board/acer/picasso.rst
new file mode 100644
index 00000000000..b1d360defd8
--- /dev/null
+++ b/doc/board/acer/picasso.rst
@@ -0,0 +1,125 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+U-Boot for the Acer Iconia Tab A500
+===================================
+
+``DISCLAMER!`` Moving your Acer Iconia Tab A500 to use U-Boot assumes
+replacement of the vendor Acer bootloader. Vendor Android firmwares will no
+longer be able to run on the device. This replacement IS reversible.
+
+Quick Start
+-----------
+
+- Build U-Boot
+- Process U-Boot
+- Flashing U-Boot into the eMMC
+- Boot
+- Self Upgrading
+
+Build U-Boot
+------------
+
+.. code-block:: bash
+
+    $ export CROSS_COMPILE=arm-none-eabi-
+    $ make picasso_defconfig
+    $ 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.
+
+Permanent installation can be performed either by using the nv3p protocol or by
+pre-loading just built U-Boot into RAM.
+
+Processing for the NV3P protocol
+********************************
+
+.. 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 a500
+
+The script will produce a ``repart-block.bin`` ready to flash.
+
+Processing for pre-loaded U-Boot
+********************************
+
+The procedure is the same, but the ``--split`` argument is used with the
+``re-crypt.py``. The script will produce ``bct.img`` and ``ebt.img`` ready
+to flash.
+
+Flashing U-Boot into the eMMC
+-----------------------------
+
+``DISCLAMER!`` All questions related to NvFlash should be asked in the proper
+place. NOT HERE! Flashing U-Boot will erase all eMMC, so make a backup before!
+
+Permanent installation can be performed either by using the nv3p protocol or by
+pre-loading just built U-Boot into RAM.
+
+Flashing with the NV3P protocol
+*******************************
+
+Nv3p is a custom Nvidia protocol used to recover bricked devices. Devices can
+enter it either by pre-loading vendor bootloader into RAM with the nvflash.
+
+With nv3p, ``repart-block.bin`` is used. It contains BCT and a bootloader in
+encrypted state in form, which can just be written RAW at the start of eMMC.
+
+.. code-block:: bash
+
+    $ nvflash --setbct --bct picasso.bct --configfile flash.cfg --bl bootloader.bin
+        --sbk 0xXXXXXXXX 0xXXXXXXXX 0xXXXXXXXX 0xXXXXXXXX --sync # replace with your SBK
+    $ nvflash --resume --rawdevicewrite 0 1024 repart-block.bin
+
+When flashing is done, reboot the device.
+
+Flashing with a pre-loaded U-Boot
+*********************************
+
+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 tablet. 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.
diff --git a/doc/board/index.rst b/doc/board/index.rst
index 74c4dd1f42d..b055046e649 100644
--- a/doc/board/index.rst
+++ b/doc/board/index.rst
@@ -6,6 +6,7 @@ Board-specific doc
 .. toctree::
    :maxdepth: 2
 
+   acer/index
    actions/index
    advantech/index
    andestech/index