doc: relocate/rename Android README and add BCB overview

Rename:
 - doc/{README.avb2 => android/avb2.txt}
 - doc/{README.android-fastboot => android/fastboot.txt}

Add a new file documenting the 'bcb' command:
 - doc/android/bcb.txt

The new directory structure has been reviewed by Simon in
https://patchwork.ozlabs.org/patch/1101107/#2176031 .

Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 214 insertions, 0 deletions

diff --git a/doc/android/fastboot.txt b/doc/android/fastboot.txt
new file mode 100644
index 0000000000..431191c473
--- /dev/null
+++ b/doc/android/fastboot.txt
@@ -0,0 +1,214 @@
+================
+Android Fastboot
+================
+
+Overview
+========
+
+The protocol that is used over USB and UDP is described in the
+``README.android-fastboot-protocol`` file in the same directory.
+
+The current implementation supports the following standard commands:
+
+- ``boot``
+- ``continue``
+- ``download``
+- ``erase`` (if enabled)
+- ``flash`` (if enabled)
+- ``getvar``
+- ``reboot``
+- ``reboot-bootloader``
+- ``set_active`` (only a stub implementation which always succeeds)
+
+The following OEM commands are supported (if enabled):
+
+- oem format - this executes ``gpt write mmc %x $partitions``
+
+Support for both eMMC and NAND devices is included.
+
+Client installation
+===================
+
+The counterpart to this is the fastboot client which can be found in
+Android's ``platform/system/core`` repository in the fastboot
+folder. It runs on Windows, Linux and OSX. The fastboot client is
+part of the Android SDK Platform-Tools and can be downloaded from:
+
+https://developer.android.com/studio/releases/platform-tools
+
+Board specific
+==============
+
+USB configuration
+-----------------
+
+The fastboot gadget relies on the USB download gadget, so the following
+options must be configured:
+
+::
+
+   CONFIG_USB_GADGET_DOWNLOAD
+   CONFIG_USB_GADGET_VENDOR_NUM
+   CONFIG_USB_GADGET_PRODUCT_NUM
+   CONFIG_USB_GADGET_MANUFACTURER
+
+NOTE: The ``CONFIG_USB_GADGET_VENDOR_NUM`` must be one of the numbers
+supported by the fastboot client. The list of vendor IDs supported can
+be found in the fastboot client source code.
+
+General configuration
+---------------------
+
+The fastboot protocol requires a large memory buffer for
+downloads. This buffer should be as large as possible for a
+platform. The location of the buffer and size are set with
+``CONFIG_FASTBOOT_BUF_ADDR`` and ``CONFIG_FASTBOOT_BUF_SIZE``. These
+may be overridden on the fastboot command line using ``-l`` and
+``-s``.
+
+Fastboot environment variables
+==============================
+
+Partition aliases
+-----------------
+
+Fastboot partition aliases can also be defined for devices where GPT
+limitations prevent user-friendly partition names such as "boot", "system"
+and "cache".  Or, where the actual partition name doesn't match a standard
+partition name used commonly with fastboot.
+
+The current implementation checks aliases when accessing partitions by
+name (flash_write and erase functions).  To define a partition alias
+add an environment variable similar to:
+
+``fastboot_partition_alias_<alias partition name>=<actual partition name>``
+
+for example:
+
+``fastboot_partition_alias_boot=LNX``
+
+Variable overrides
+------------------
+
+Variables retrived through ``getvar`` can be overridden by defining
+environment variables of the form ``fastboot.<variable>``. These are
+looked up first so can be used to override values which would
+otherwise be returned. Using this mechanism you can also return types
+for NAND filesystems, as the fully parameterised variable is looked
+up, e.g.
+
+``fastboot.partition-type:boot=jffs2``
+
+Boot command
+------------
+
+When executing the fastboot ``boot`` command, if ``fastboot_bootcmd`` is set then
+that will be executed in place of ``bootm <CONFIG_FASTBOOT_BUF_ADDR>``.
+
+Partition Names
+===============
+
+The Fastboot implementation in U-Boot allows to write images into disk
+partitions. Target partitions are referred on the host computer by
+their names.
+
+For GPT/EFI the respective partition name is used.
+
+For MBR the partitions are referred by generic names according to the
+following schema:
+
+  <device type><device index letter><partition index>
+
+Example: ``hda3``, ``sdb1``, ``usbda1``
+
+The device type is as follows:
+
+  * IDE, ATAPI and SATA disks: ``hd``
+  * SCSI disks: ``sd``
+  * USB media: ``usbd``
+  * MMC and SD cards: ``mmcsd``
+  * Disk on chip: ``docd``
+  * other: ``xx``
+
+The device index starts from ``a`` and refers to the interface (e.g. USB
+controller, SD/MMC controller) or disk index. The partition index starts
+from ``1`` and describes the partition number on the particular device.
+
+Writing Partition Table
+=======================
+
+Fastboot also allows to write the partition table to the media. This can be
+done by writing the respective partition table image to a special target
+"gpt" or "mbr". These names can be customized by defining the following
+configuration options:
+
+::
+
+   CONFIG_FASTBOOT_GPT_NAME
+   CONFIG_FASTBOOT_MBR_NAME
+
+In Action
+=========
+
+Enter into fastboot by executing the fastboot command in U-Boot for either USB:
+
+::
+
+   => fastboot usb 0
+
+or UDP:
+
+::
+
+   => fastboot udp
+   link up on port 0, speed 100, full duplex
+   Using ethernet@4a100000 device
+   Listening for fastboot command on 192.168.0.102
+
+On the client side you can fetch the bootloader version for instance:
+
+::
+
+   $ fastboot getvar bootloader-version
+   bootloader-version: U-Boot 2014.04-00005-gd24cabc
+   finished. total time: 0.000s
+
+or initiate a reboot:
+
+::
+
+   $ fastboot reboot
+
+and once the client comes back, the board should reset.
+
+You can also specify a kernel image to boot. You have to either specify
+the an image in Android format *or* pass a binary kernel and let the
+fastboot client wrap the Android suite around it. On OMAP for instance you
+take zImage kernel and pass it to the fastboot client:
+
+::
+
+   $ fastboot -b 0x80000000 -c "console=ttyO2 earlyprintk root=/dev/ram0 mem=128M" boot zImage
+   creating boot image...
+   creating boot image - 1847296 bytes
+   downloading 'boot.img'...
+   OKAY [  2.766s]
+   booting...
+   OKAY [ -0.000s]
+   finished. total time: 2.766s
+
+and on the U-Boot side you should see:
+
+::
+
+   Starting download of 1847296 bytes
+   ........................................................
+   downloading of 1847296 bytes finished
+   Booting kernel..
+   ## Booting Android Image at 0x81000000 ...
+   Kernel load addr 0x80008000 size 1801 KiB
+   Kernel command line: console=ttyO2 earlyprintk root=/dev/ram0 mem=128M
+      Loading Kernel Image ... OK
+   OK
+
+   Starting kernel ...