usb/gadget: add the fastboot gadget

This patch contains an implementation of the fastboot protocol on the
device side and documentation. This is based on USB download gadget
infrastructure. The fastboot function implements the getvar, reboot,
download and reboot commands. What is missing is the flash handling i.e.
writting the image to media.

v3 (Rob Herring):
This is based on http://patchwork.ozlabs.org/patch/126798/ with the
following changes:
- Rebase to current mainline and updates for current gadget API
- Use SPDX identifiers for licenses
- Traced the history and added missing copyright to cmd_fastboot.c
- Use load_addr/load_size for transfer buffer
- Allow vendor strings to be optional
- Set vendor/product ID from config defines
- Allow Ctrl-C to exit fastboot mode
v4:
- Major re-write to use the USB download gadget. Consolidated function
code to a single file.
- Moved globals into single struct.
- Use puts and putc as appropriate.
- Added CONFIG_USB_FASTBOOT_BUF_ADDR and CONFIG_USB_FASTBOOT_BUF_SIZE to
set the fastboot transfer buffer.
v5:
- Add CONFIG option documentation to README
- Rebase using new downloader registration

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Rob Herring <robh@kernel.org>

1 files changed, 91 insertions, 0 deletions

diff --git a/doc/README.android-fastboot b/doc/README.android-fastboot
new file mode 100644
index 0000000000..f1d128caa9
--- /dev/null
+++ b/doc/README.android-fastboot
@@ -0,0 +1,91 @@
+Android Fastboot
+~~~~~~~~~~~~~~~~
+
+Overview
+========
+The protocol that is used over USB is described in
+README.android-fastboot-protocol in same directory.
+
+The current implementation does not yet support the flash and erase
+commands.
+
+Client installation
+===================
+The counterpart to this gadget 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 even OSX. Linux user are lucky since
+they only need libusb.
+Windows users need to bring some time until they have Android SDK (currently
+http://dl.google.com/android/installer_r12-windows.exe) installed. You
+need to install ADB package which contains the required glue libraries for
+accessing USB. Also you need "Google USB driver package" and "SDK platform
+tools". Once installed the usb driver is placed in your SDK folder under
+extras\google\usb_driver. The android_winusb.inf needs a line like
+
+   %SingleBootLoaderInterface% = USB_Install, USB\VID_0451&PID_D022
+
+either in the [Google.NTx86] section for 32bit Windows or [Google.NTamd64]
+for 64bit Windows. VID and PID should match whatever the fastboot is
+advertising.
+
+Board specific
+==============
+The fastboot gadget relies on the USB download gadget, so the following
+options must be configured:
+
+CONFIG_USBDOWNLOAD_GADGET
+CONFIG_G_DNL_VENDOR_NUM
+CONFIG_G_DNL_PRODUCT_NUM
+CONFIG_G_DNL_MANUFACTURER
+
+The fastboot function is enabled by defining CONFIG_CMD_FASTBOOT and
+CONFIG_ANDROID_BOOT_IMAGE.
+
+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_USB_FASTBOOT_BUF_ADDR and
+CONFIG_USB_FASTBOOT_BUF_SIZE.
+
+In Action
+=========
+Enter into fastboot by executing the fastboot command in u-boot and you
+should see:
+|GADGET DRIVER: usb_dnl_fastboot
+
+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 gadget 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 ...