doc: android: Convert to Sphinx format
Convert Android documentation from regular txt format to Sphinx (RST).
Also add Android index.rst file and reference it in root index.rst, so
that Android documentation is visible.
Test:
$ make htmldocs
$ xdg-open doc/output/index.html
Signed-off-by: Sam Protsenko <joe.skb7@gmail.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
This commit is contained in:
Sam Protsenko
Lokesh Vutla
parent
34b4319304
commit
586a1bf5b2
@ -56,7 +56,7 @@ R: Sam Protsenko <joe.skb7@gmail.com>
|
||||
S: Maintained
|
||||
F: cmd/ab_select.c
|
||||
F: common/android_ab.c
|
||||
F: doc/android/ab.txt
|
||||
F: doc/android/ab.rst
|
||||
F: include/android_ab.h
|
||||
F: test/py/tests/test_android/test_ab.py
|
||||
|
||||
@ -65,7 +65,7 @@ M: Igor Opaniuk <igor.opaniuk@gmail.com>
|
||||
S: Maintained
|
||||
F: cmd/avb.c
|
||||
F: common/avb_verify.c
|
||||
F: doc/android/avb2.txt
|
||||
F: doc/android/avb2.rst
|
||||
F: include/avb_verify.h
|
||||
F: lib/libavb/
|
||||
F: test/py/tests/test_android/test_avb.py
|
||||
|
||||
@ -880,7 +880,7 @@ config CMD_FASTBOOT
|
||||
Android devices. Fastboot requires either the network stack
|
||||
enabled or support for acting as a USB device.
|
||||
|
||||
See doc/android/fastboot.txt for more information.
|
||||
See doc/android/fastboot.rst for more information.
|
||||
|
||||
config CMD_FLASH
|
||||
bool "flinfo, erase, protect"
|
||||
|
||||
@ -1,3 +1,5 @@
|
||||
.. SPDX-License-Identifier: GPL-2.0+
|
||||
|
||||
Android A/B updates
|
||||
===================
|
||||
|
||||
@ -7,41 +9,44 @@ Overview
|
||||
A/B system updates ensures modern approach for system update. This feature
|
||||
allows one to use two sets (or more) of partitions referred to as slots
|
||||
(normally slot A and slot B). The system runs from the current slot while the
|
||||
partitions in the unused slot can be updated [1].
|
||||
partitions in the unused slot can be updated [1]_.
|
||||
|
||||
A/B enablement
|
||||
--------------
|
||||
|
||||
The A/B updates support can be activated by specifying next options in
|
||||
your board configuration file:
|
||||
your board configuration file::
|
||||
|
||||
CONFIG_ANDROID_AB=y
|
||||
CONFIG_CMD_AB_SELECT=y
|
||||
|
||||
The disk space on target device must be partitioned in a way so that each
|
||||
partition which needs to be updated has two or more instances. The name of
|
||||
each instance must be formed by adding suffixes: _a, _b, _c, etc.
|
||||
For example: boot_a, boot_b, system_a, system_b, vendor_a, vendor_b.
|
||||
each instance must be formed by adding suffixes: ``_a``, ``_b``, ``_c``, etc.
|
||||
For example: ``boot_a``, ``boot_b``, ``system_a``, ``system_b``, ``vendor_a``,
|
||||
``vendor_b``.
|
||||
|
||||
As a result you can use 'ab_select' command to ensure A/B boot process in your
|
||||
As a result you can use ``ab_select`` command to ensure A/B boot process in your
|
||||
boot script. This command analyzes and processes A/B metadata stored on a
|
||||
special partition (e.g. "misc") and determines which slot should be used for
|
||||
special partition (e.g. ``misc``) and determines which slot should be used for
|
||||
booting up.
|
||||
|
||||
Command usage
|
||||
-------------
|
||||
|
||||
.. code-block:: none
|
||||
|
||||
ab_select <slot_var_name> <interface> <dev[:part_number|#part_name]>
|
||||
|
||||
for example:
|
||||
for example::
|
||||
|
||||
=> ab_select slot_name mmc 1:4
|
||||
|
||||
or
|
||||
or::
|
||||
|
||||
=> ab_select slot_name mmc 1#misc
|
||||
|
||||
Result:
|
||||
Result::
|
||||
|
||||
=> printenv slot_name
|
||||
slot_name=a
|
||||
@ -49,19 +54,19 @@ Result:
|
||||
Based on this slot information, the current boot partition should be defined,
|
||||
and next kernel command line parameters should be generated:
|
||||
|
||||
- androidboot.slot_suffix=
|
||||
- root=
|
||||
* ``androidboot.slot_suffix=``
|
||||
* ``root=``
|
||||
|
||||
For example:
|
||||
For example::
|
||||
|
||||
androidboot.slot_suffix=_a root=/dev/mmcblk1p12
|
||||
|
||||
A/B metadata is organized according to AOSP reference [2]. On the first system
|
||||
start with A/B enabled, when 'misc' partition doesn't contain required data,
|
||||
the default A/B metadata will be created and written to 'misc' partition.
|
||||
A/B metadata is organized according to AOSP reference [2]_. On the first system
|
||||
start with A/B enabled, when ``misc`` partition doesn't contain required data,
|
||||
the default A/B metadata will be created and written to ``misc`` partition.
|
||||
|
||||
References
|
||||
----------
|
||||
|
||||
[1] https://source.android.com/devices/tech/ota/ab
|
||||
[2] bootable/recovery/bootloader_message/include/bootloader_message/bootloader_message.h
|
||||
.. [1] https://source.android.com/devices/tech/ota/ab
|
||||
.. [2] https://android.googlesource.com/platform/bootable/recovery/+/refs/tags/android-10.0.0_r25/bootloader_message/include/bootloader_message/bootloader_message.h
|
||||
133
doc/android/avb2.rst
Normal file
133
doc/android/avb2.rst
Normal file
@ -0,0 +1,133 @@
|
||||
.. SPDX-License-Identifier: GPL-2.0+
|
||||
|
||||
Android Verified Boot 2.0
|
||||
=========================
|
||||
|
||||
This file contains information about the current support of Android Verified
|
||||
Boot 2.0 in U-Boot.
|
||||
|
||||
Overview
|
||||
--------
|
||||
|
||||
Verified Boot establishes a chain of trust from the bootloader to system images:
|
||||
|
||||
* Provides integrity checking for:
|
||||
|
||||
* Android Boot image: Linux kernel + ramdisk. RAW hashing of the whole
|
||||
partition is done and the hash is compared with the one stored in
|
||||
the VBMeta image
|
||||
* ``system``/``vendor`` partitions: verifying root hash of dm-verity hashtrees
|
||||
|
||||
* Provides capabilities for rollback protection
|
||||
|
||||
Integrity of the bootloader (U-Boot BLOB and environment) is out of scope.
|
||||
|
||||
For additional details check [1]_.
|
||||
|
||||
AVB using OP-TEE (optional)
|
||||
^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
If AVB is configured to use OP-TEE (see `Enable on your board`_) rollback
|
||||
indexes and device lock state are stored in RPMB. The RPMB partition is managed
|
||||
by OP-TEE (see [2]_ for details) which is a secure OS leveraging ARM
|
||||
TrustZone.
|
||||
|
||||
AVB 2.0 U-Boot shell commands
|
||||
-----------------------------
|
||||
|
||||
Provides CLI interface to invoke AVB 2.0 verification + misc. commands for
|
||||
different testing purposes::
|
||||
|
||||
avb init <dev> - initialize avb 2.0 for <dev>
|
||||
avb verify - run verification process using hash data from vbmeta structure
|
||||
avb read_rb <num> - read rollback index at location <num>
|
||||
avb write_rb <num> <rb> - write rollback index <rb> to <num>
|
||||
avb is_unlocked - returns unlock status of the device
|
||||
avb get_uuid <partname> - read and print uuid of partition <partname>
|
||||
avb read_part <partname> <offset> <num> <addr> - read <num> bytes from
|
||||
partition <partname> to buffer <addr>
|
||||
avb write_part <partname> <offset> <num> <addr> - write <num> bytes to
|
||||
<partname> by <offset> using data from <addr>
|
||||
|
||||
Partitions tampering (example)
|
||||
------------------------------
|
||||
|
||||
Boot or system/vendor (dm-verity metadata section) is tampered::
|
||||
|
||||
=> avb init 1
|
||||
=> avb verify
|
||||
avb_slot_verify.c:175: ERROR: boot: Hash of data does not match digest in
|
||||
descriptor.
|
||||
Slot verification result: ERROR_IO
|
||||
|
||||
Vbmeta partition is tampered::
|
||||
|
||||
=> avb init 1
|
||||
=> avb verify
|
||||
avb_vbmeta_image.c:206: ERROR: Hash does not match!
|
||||
avb_slot_verify.c:388: ERROR: vbmeta: Error verifying vbmeta image:
|
||||
HASH_MISMATCH
|
||||
Slot verification result: ERROR_IO
|
||||
|
||||
Enable on your board
|
||||
--------------------
|
||||
|
||||
The following options must be enabled::
|
||||
|
||||
CONFIG_LIBAVB=y
|
||||
CONFIG_AVB_VERIFY=y
|
||||
CONFIG_CMD_AVB=y
|
||||
|
||||
In addtion optionally if storing rollback indexes in RPMB with help of
|
||||
OP-TEE::
|
||||
|
||||
CONFIG_TEE=y
|
||||
CONFIG_OPTEE=y
|
||||
CONFIG_OPTEE_TA_AVB=y
|
||||
CONFIG_SUPPORT_EMMC_RPMB=y
|
||||
|
||||
Then add ``avb verify`` invocation to your android boot sequence of commands,
|
||||
e.g.::
|
||||
|
||||
=> avb_verify=avb init $mmcdev; avb verify;
|
||||
=> if run avb_verify; then \
|
||||
echo AVB verification OK. Continue boot; \
|
||||
set bootargs $bootargs $avb_bootargs; \
|
||||
else \
|
||||
echo AVB verification failed; \
|
||||
exit; \
|
||||
fi; \
|
||||
|
||||
=> emmc_android_boot= \
|
||||
echo Trying to boot Android from eMMC ...; \
|
||||
... \
|
||||
run avb_verify; \
|
||||
mmc read ${fdtaddr} ${fdt_start} ${fdt_size}; \
|
||||
mmc read ${loadaddr} ${boot_start} ${boot_size}; \
|
||||
bootm $loadaddr $loadaddr $fdtaddr; \
|
||||
|
||||
If partitions you want to verify are slotted (have A/B suffixes), then current
|
||||
slot suffix should be passed to ``avb verify`` sub-command, e.g.::
|
||||
|
||||
=> avb verify _a
|
||||
|
||||
To switch on automatic generation of vbmeta partition in AOSP build, add these
|
||||
lines to device configuration mk file::
|
||||
|
||||
BOARD_AVB_ENABLE := true
|
||||
BOARD_AVB_ALGORITHM := SHA512_RSA4096
|
||||
BOARD_BOOTIMAGE_PARTITION_SIZE := <boot partition size>
|
||||
|
||||
After flashing U-Boot don't forget to update environment and write new
|
||||
partition table::
|
||||
|
||||
=> env default -f -a
|
||||
=> setenv partitions $partitions_android
|
||||
=> env save
|
||||
=> gpt write mmc 1 $partitions_android
|
||||
|
||||
References
|
||||
----------
|
||||
|
||||
.. [1] https://android.googlesource.com/platform/external/avb/+/master/README.md
|
||||
.. [2] https://www.op-tee.org/
|
||||
@ -1,115 +0,0 @@
|
||||
Android Verified Boot 2.0
|
||||
|
||||
This file contains information about the current support of Android Verified
|
||||
Boot 2.0 in U-boot
|
||||
|
||||
1. OVERVIEW
|
||||
---------------------------------
|
||||
Verified Boot establishes a chain of trust from the bootloader to system images
|
||||
* Provides integrity checking for:
|
||||
- Android Boot image: Linux kernel + ramdisk. RAW hashing of the whole
|
||||
partition is done and the hash is compared with the one stored in
|
||||
the VBMeta image
|
||||
- system/vendor partitions: verifying root hash of dm-verity hashtrees.
|
||||
* Provides capabilities for rollback protection.
|
||||
|
||||
Integrity of the bootloader (U-boot BLOB and environment) is out of scope.
|
||||
|
||||
For additional details check:
|
||||
https://android.googlesource.com/platform/external/avb/+/master/README.md
|
||||
|
||||
1.1. AVB using OP-TEE (optional)
|
||||
---------------------------------
|
||||
If AVB is configured to use OP-TEE (see 4. below) rollback indexes and
|
||||
device lock state are stored in RPMB. The RPMB partition is managed by
|
||||
OP-TEE (https://www.op-tee.org/) which is a secure OS leveraging ARM
|
||||
TrustZone.
|
||||
|
||||
|
||||
2. AVB 2.0 U-BOOT SHELL COMMANDS
|
||||
-----------------------------------
|
||||
Provides CLI interface to invoke AVB 2.0 verification + misc. commands for
|
||||
different testing purposes:
|
||||
|
||||
avb init <dev> - initialize avb 2.0 for <dev>
|
||||
avb verify - run verification process using hash data from vbmeta structure
|
||||
avb read_rb <num> - read rollback index at location <num>
|
||||
avb write_rb <num> <rb> - write rollback index <rb> to <num>
|
||||
avb is_unlocked - returns unlock status of the device
|
||||
avb get_uuid <partname> - read and print uuid of partition <partname>
|
||||
avb read_part <partname> <offset> <num> <addr> - read <num> bytes from
|
||||
partition <partname> to buffer <addr>
|
||||
avb write_part <partname> <offset> <num> <addr> - write <num> bytes to
|
||||
<partname> by <offset> using data from <addr>
|
||||
|
||||
|
||||
3. PARTITIONS TAMPERING (EXAMPLE)
|
||||
-----------------------------------
|
||||
Boot or system/vendor (dm-verity metadata section) is tampered:
|
||||
=> avb init 1
|
||||
=> avb verify
|
||||
avb_slot_verify.c:175: ERROR: boot: Hash of data does not match digest in
|
||||
descriptor.
|
||||
Slot verification result: ERROR_IO
|
||||
|
||||
Vbmeta partition is tampered:
|
||||
=> avb init 1
|
||||
=> avb verify
|
||||
avb_vbmeta_image.c:206: ERROR: Hash does not match!
|
||||
avb_slot_verify.c:388: ERROR: vbmeta: Error verifying vbmeta image:
|
||||
HASH_MISMATCH
|
||||
Slot verification result: ERROR_IO
|
||||
|
||||
|
||||
4. ENABLE ON YOUR BOARD
|
||||
-----------------------------------
|
||||
The following options must be enabled:
|
||||
CONFIG_LIBAVB=y
|
||||
CONFIG_AVB_VERIFY=y
|
||||
CONFIG_CMD_AVB=y
|
||||
|
||||
In addtion optionally if storing rollback indexes in RPMB with help of
|
||||
OP-TEE:
|
||||
CONFIG_TEE=y
|
||||
CONFIG_OPTEE=y
|
||||
CONFIG_OPTEE_TA_AVB=y
|
||||
CONFIG_SUPPORT_EMMC_RPMB=y
|
||||
|
||||
Then add `avb verify` invocation to your android boot sequence of commands,
|
||||
e.g.:
|
||||
|
||||
=> avb_verify=avb init $mmcdev; avb verify;
|
||||
=> if run avb_verify; then \
|
||||
echo AVB verification OK. Continue boot; \
|
||||
set bootargs $bootargs $avb_bootargs; \
|
||||
else \
|
||||
echo AVB verification failed; \
|
||||
exit; \
|
||||
fi; \
|
||||
|
||||
=> emmc_android_boot= \
|
||||
echo Trying to boot Android from eMMC ...; \
|
||||
... \
|
||||
run avb_verify; \
|
||||
mmc read ${fdtaddr} ${fdt_start} ${fdt_size}; \
|
||||
mmc read ${loadaddr} ${boot_start} ${boot_size}; \
|
||||
bootm $loadaddr $loadaddr $fdtaddr; \
|
||||
|
||||
If partitions you want to verify are slotted (have A/B suffixes), then current
|
||||
slot suffix should be passed to 'avb verify' sub-command, e.g.:
|
||||
|
||||
=> avb verify _a
|
||||
|
||||
To switch on automatic generation of vbmeta partition in AOSP build, add these
|
||||
lines to device configuration mk file:
|
||||
|
||||
BOARD_AVB_ENABLE := true
|
||||
BOARD_AVB_ALGORITHM := SHA512_RSA4096
|
||||
BOARD_BOOTIMAGE_PARTITION_SIZE := <boot partition size>
|
||||
|
||||
After flashing U-boot don't forget to update environment and write new
|
||||
partition table:
|
||||
=> env default -f -a
|
||||
=> setenv partitions $partitions_android
|
||||
=> env save
|
||||
=> gpt write mmc 1 $partitions_android
|
||||
100
doc/android/bcb.rst
Normal file
100
doc/android/bcb.rst
Normal file
@ -0,0 +1,100 @@
|
||||
.. SPDX-License-Identifier: GPL-2.0+
|
||||
|
||||
Android Bootloader Control Block (BCB)
|
||||
======================================
|
||||
|
||||
The purpose behind this file is to:
|
||||
|
||||
* give an overview of BCB w/o duplicating public documentation
|
||||
* describe the main BCB use-cases which concern U-Boot
|
||||
* reflect current support status in U-Boot
|
||||
* mention any relevant U-Boot build-time tunables
|
||||
* precisely exemplify one or more use-cases
|
||||
|
||||
Additions and fixes are welcome!
|
||||
|
||||
Overview
|
||||
--------
|
||||
|
||||
Bootloader Control Block (BCB) is a well established term/acronym in
|
||||
the Android namespace which refers to a location in a dedicated raw
|
||||
(i.e. FS-unaware) flash (e.g. eMMC) partition, usually called ``misc``,
|
||||
which is used as media for exchanging messages between Android userspace
|
||||
(particularly recovery [1]_) and an Android-capable bootloader.
|
||||
|
||||
On higher level, BCB provides a way to implement a subset of Android
|
||||
Bootloader Requirements [2]_, amongst which are:
|
||||
|
||||
* Android-specific bootloader flow [3]_
|
||||
* Get the "reboot reason" (and act accordingly) [4]_
|
||||
* Get/pass a list of commands from/to recovery [1]_
|
||||
* TODO
|
||||
|
||||
|
||||
'bcb'. Shell command overview
|
||||
-----------------------------
|
||||
|
||||
The ``bcb`` command provides a CLI to facilitate the development of the
|
||||
requirements enumerated above. Below is the command's help message::
|
||||
|
||||
=> bcb
|
||||
bcb - Load/set/clear/test/dump/store Android BCB fields
|
||||
|
||||
Usage:
|
||||
bcb load <dev> <part> - load BCB from mmc <dev>:<part>
|
||||
bcb set <field> <val> - set BCB <field> to <val>
|
||||
bcb clear [<field>] - clear BCB <field> or all fields
|
||||
bcb test <field> <op> <val> - test BCB <field> against <val>
|
||||
bcb dump <field> - dump BCB <field>
|
||||
bcb store - store BCB back to mmc
|
||||
|
||||
Legend:
|
||||
<dev> - MMC device index containing the BCB partition
|
||||
<part> - MMC partition index or name containing the BCB
|
||||
<field> - one of {command,status,recovery,stage,reserved}
|
||||
<op> - the binary operator used in 'bcb test':
|
||||
'=' returns true if <val> matches the string stored in <field>
|
||||
'~' returns true if <val> matches a subset of <field>'s string
|
||||
<val> - string/text provided as input to bcb {set,test}
|
||||
NOTE: any ':' character in <val> will be replaced by line feed
|
||||
during 'bcb set' and used as separator by upper layers
|
||||
|
||||
|
||||
'bcb'. Example of getting reboot reason
|
||||
---------------------------------------
|
||||
|
||||
.. code-block:: bash
|
||||
|
||||
if bcb load 1 misc; then
|
||||
# valid BCB found
|
||||
if bcb test command = bootonce-bootloader; then
|
||||
bcb clear command; bcb store;
|
||||
# do the equivalent of AOSP ${fastbootcmd}
|
||||
# i.e. call fastboot
|
||||
else if bcb test command = boot-recovery; then
|
||||
bcb clear command; bcb store;
|
||||
# do the equivalent of AOSP ${recoverycmd}
|
||||
# i.e. do anything required for booting into recovery
|
||||
else
|
||||
# boot Android OS normally
|
||||
fi
|
||||
else
|
||||
# corrupted/non-existent BCB
|
||||
# report error or boot non-Android OS (platform-specific)
|
||||
fi
|
||||
|
||||
|
||||
Enable on your board
|
||||
--------------------
|
||||
|
||||
The following Kconfig options must be enabled::
|
||||
|
||||
CONFIG_PARTITIONS=y
|
||||
CONFIG_MMC=y
|
||||
CONFIG_BCB=y
|
||||
|
||||
.. [1] https://android.googlesource.com/platform/bootable/recovery
|
||||
.. [2] https://source.android.com/devices/bootloader
|
||||
.. [3] https://patchwork.ozlabs.org/patch/746835/
|
||||
("[U-Boot,5/6] Initial support for the Android Bootloader flow")
|
||||
.. [4] https://source.android.com/devices/bootloader/boot-reason
|
||||
@ -1,89 +0,0 @@
|
||||
Android Bootloader Control Block (BCB)
|
||||
|
||||
The purpose behind this file is to:
|
||||
- give an overview of BCB w/o duplicating public documentation
|
||||
- describe the main BCB use-cases which concern U-Boot
|
||||
- reflect current support status in U-Boot
|
||||
- mention any relevant U-Boot build-time tunables
|
||||
- precisely exemplify one or more use-cases
|
||||
|
||||
Additions and fixes are welcome!
|
||||
|
||||
|
||||
1. OVERVIEW
|
||||
---------------------------------
|
||||
Bootloader Control Block (BCB) is a well established term/acronym in
|
||||
the Android namespace which refers to a location in a dedicated raw
|
||||
(i.e. FS-unaware) flash (e.g. eMMC) partition, usually called "misc",
|
||||
which is used as media for exchanging messages between Android userspace
|
||||
(particularly recovery [1]) and an Android-capable bootloader.
|
||||
|
||||
On higher level, BCB provides a way to implement a subset of Android
|
||||
Bootloader Requirements [2], amongst which are:
|
||||
- Android-specific bootloader flow [3]
|
||||
- Get the "reboot reason" (and act accordingly) [4]
|
||||
- Get/pass a list of commands from/to recovery [1]
|
||||
- TODO
|
||||
|
||||
|
||||
2. 'BCB'. SHELL COMMAND OVERVIEW
|
||||
-----------------------------------
|
||||
The 'bcb' command provides a CLI to facilitate the development of the
|
||||
requirements enumerated above. Below is the command's help message:
|
||||
|
||||
=> bcb
|
||||
bcb - Load/set/clear/test/dump/store Android BCB fields
|
||||
|
||||
Usage:
|
||||
bcb load <dev> <part> - load BCB from mmc <dev>:<part>
|
||||
bcb set <field> <val> - set BCB <field> to <val>
|
||||
bcb clear [<field>] - clear BCB <field> or all fields
|
||||
bcb test <field> <op> <val> - test BCB <field> against <val>
|
||||
bcb dump <field> - dump BCB <field>
|
||||
bcb store - store BCB back to mmc
|
||||
|
||||
Legend:
|
||||
<dev> - MMC device index containing the BCB partition
|
||||
<part> - MMC partition index or name containing the BCB
|
||||
<field> - one of {command,status,recovery,stage,reserved}
|
||||
<op> - the binary operator used in 'bcb test':
|
||||
'=' returns true if <val> matches the string stored in <field>
|
||||
'~' returns true if <val> matches a subset of <field>'s string
|
||||
<val> - string/text provided as input to bcb {set,test}
|
||||
NOTE: any ':' character in <val> will be replaced by line feed
|
||||
during 'bcb set' and used as separator by upper layers
|
||||
|
||||
|
||||
3. 'BCB'. EXAMPLE OF GETTING REBOOT REASON
|
||||
-----------------------------------
|
||||
if bcb load 1 misc; then
|
||||
# valid BCB found
|
||||
if bcb test command = bootonce-bootloader; then
|
||||
bcb clear command; bcb store;
|
||||
# do the equivalent of AOSP ${fastbootcmd}
|
||||
# i.e. call fastboot
|
||||
else if bcb test command = boot-recovery; then
|
||||
bcb clear command; bcb store;
|
||||
# do the equivalent of AOSP ${recoverycmd}
|
||||
# i.e. do anything required for booting into recovery
|
||||
else
|
||||
# boot Android OS normally
|
||||
fi
|
||||
else
|
||||
# corrupted/non-existent BCB
|
||||
# report error or boot non-Android OS (platform-specific)
|
||||
fi
|
||||
|
||||
|
||||
4. ENABLE ON YOUR BOARD
|
||||
-----------------------------------
|
||||
The following Kconfig options must be enabled:
|
||||
CONFIG_PARTITIONS=y
|
||||
CONFIG_MMC=y
|
||||
CONFIG_BCB=y
|
||||
|
||||
[1] https://android.googlesource.com/platform/bootable/recovery
|
||||
[2] https://source.android.com/devices/bootloader
|
||||
[3] https://patchwork.ozlabs.org/patch/746835/
|
||||
("[U-Boot,5/6] Initial support for the Android Bootloader flow")
|
||||
[4] https://source.android.com/devices/bootloader/boot-reason
|
||||
@ -1,12 +1,13 @@
|
||||
FastBoot Version 0.4
|
||||
----------------------
|
||||
.. SPDX-License-Identifier: GPL-2.0+
|
||||
|
||||
FastBoot Version 0.4
|
||||
====================
|
||||
|
||||
The fastboot protocol is a mechanism for communicating with bootloaders
|
||||
over USB. It is designed to be very straightforward to implement, to
|
||||
allow it to be used across a wide range of devices and from hosts running
|
||||
Linux, Windows, or OSX.
|
||||
|
||||
|
||||
Basic Requirements
|
||||
------------------
|
||||
|
||||
@ -66,31 +67,33 @@ Transport and Framing
|
||||
Example Session
|
||||
---------------
|
||||
|
||||
Host: "getvar:version" request version variable
|
||||
.. code-block:: none
|
||||
|
||||
Client: "OKAY0.4" return version "0.4"
|
||||
Host: "getvar:version" request version variable
|
||||
|
||||
Host: "getvar:nonexistant" request some undefined variable
|
||||
Client: "OKAY0.4" return version "0.4"
|
||||
|
||||
Client: "OKAY" return value ""
|
||||
Host: "getvar:nonexistant" request some undefined variable
|
||||
|
||||
Host: "download:00001234" request to send 0x1234 bytes of data
|
||||
Client: "OKAY" return value ""
|
||||
|
||||
Client: "DATA00001234" ready to accept data
|
||||
Host: "download:00001234" request to send 0x1234 bytes of data
|
||||
|
||||
Host: < 0x1234 bytes > send data
|
||||
Client: "DATA00001234" ready to accept data
|
||||
|
||||
Client: "OKAY" success
|
||||
Host: < 0x1234 bytes > send data
|
||||
|
||||
Host: "flash:bootloader" request to flash the data to the bootloader
|
||||
Client: "OKAY" success
|
||||
|
||||
Client: "INFOerasing flash" indicate status / progress
|
||||
"INFOwriting flash"
|
||||
"OKAY" indicate success
|
||||
Host: "flash:bootloader" request to flash the data to the bootloader
|
||||
|
||||
Host: "powerdown" send a command
|
||||
Client: "INFOerasing flash" indicate status / progress
|
||||
"INFOwriting flash"
|
||||
"OKAY" indicate success
|
||||
|
||||
Client: "FAILunknown command" indicate failure
|
||||
Host: "powerdown" send a command
|
||||
|
||||
Client: "FAILunknown command" indicate failure
|
||||
|
||||
|
||||
Command Reference
|
||||
@ -105,6 +108,8 @@ Command Reference
|
||||
specification. OEM-specific commands should not begin with a
|
||||
lowercase letter, to prevent incompatibilities with future specs.
|
||||
|
||||
.. code-block:: none
|
||||
|
||||
"getvar:%s" Read a config/version variable from the bootloader.
|
||||
The variable contents will be returned after the
|
||||
OKAY response.
|
||||
@ -139,16 +144,14 @@ Command Reference
|
||||
|
||||
"powerdown" Power off the device.
|
||||
|
||||
|
||||
|
||||
Client Variables
|
||||
----------------
|
||||
|
||||
The "getvar:%s" command is used to read client variables which
|
||||
The ``getvar:%s`` command is used to read client variables which
|
||||
represent various information about the device and the software
|
||||
on it.
|
||||
|
||||
The various currently defined names are:
|
||||
The various currently defined names are::
|
||||
|
||||
version Version of FastBoot protocol supported.
|
||||
It should be "0.3" for this document.
|
||||
@ -1,12 +1,12 @@
|
||||
================
|
||||
.. SPDX-License-Identifier: GPL-2.0+
|
||||
|
||||
Android Fastboot
|
||||
================
|
||||
|
||||
Overview
|
||||
========
|
||||
--------
|
||||
|
||||
The protocol that is used over USB and UDP is described in
|
||||
``doc/android/fastboot-protocol.txt``.
|
||||
The protocol that is used over USB and UDP is described in [1]_.
|
||||
|
||||
The current implementation supports the following standard commands:
|
||||
|
||||
@ -22,25 +22,23 @@ The current implementation supports the following standard commands:
|
||||
|
||||
The following OEM commands are supported (if enabled):
|
||||
|
||||
- oem format - this executes ``gpt write mmc %x $partitions``
|
||||
- ``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
|
||||
part of the Android SDK Platform-Tools and can be downloaded from [2]_.
|
||||
|
||||
Board specific
|
||||
==============
|
||||
--------------
|
||||
|
||||
USB configuration
|
||||
-----------------
|
||||
^^^^^^^^^^^^^^^^^
|
||||
|
||||
The fastboot gadget relies on the USB download gadget, so the following
|
||||
options must be configured:
|
||||
@ -57,7 +55,7 @@ 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
|
||||
@ -67,46 +65,46 @@ 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
|
||||
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:
|
||||
add an environment variable similar to::
|
||||
|
||||
``fastboot_partition_alias_<alias partition name>=<actual partition name>``
|
||||
fastboot_partition_alias_<alias partition name>=<actual partition name>
|
||||
|
||||
for example:
|
||||
for example::
|
||||
|
||||
``fastboot_partition_alias_boot=LNX``
|
||||
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.
|
||||
up, e.g.::
|
||||
|
||||
``fastboot.partition-type:boot=jffs2``
|
||||
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>``.
|
||||
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
|
||||
@ -115,11 +113,11 @@ 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:
|
||||
following schema::
|
||||
|
||||
<device type><device index letter><partition index>
|
||||
<device type><device index letter><partition index>
|
||||
|
||||
Example: ``hda3``, ``sdb1``, ``usbda1``
|
||||
Example: ``hda3``, ``sdb1``, ``usbda1``.
|
||||
|
||||
The device type is as follows:
|
||||
|
||||
@ -135,7 +133,7 @@ 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
|
||||
@ -148,34 +146,26 @@ configuration options:
|
||||
CONFIG_FASTBOOT_MBR_NAME
|
||||
|
||||
In Action
|
||||
=========
|
||||
---------
|
||||
|
||||
Enter into fastboot by executing the fastboot command in U-Boot for either USB:
|
||||
|
||||
::
|
||||
Enter into fastboot by executing the fastboot command in U-Boot for either USB::
|
||||
|
||||
=> fastboot usb 0
|
||||
|
||||
or UDP:
|
||||
|
||||
::
|
||||
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:
|
||||
|
||||
::
|
||||
On the client side you can fetch the bootloader version for instance::
|
||||
|
||||
$ fastboot getvar version-bootloader
|
||||
version-bootloader: U-Boot 2019.07-rc4-00240-g00c9f2a2ec
|
||||
Finished. Total time: 0.005s
|
||||
|
||||
or initiate a reboot:
|
||||
|
||||
::
|
||||
or initiate a reboot::
|
||||
|
||||
$ fastboot reboot
|
||||
|
||||
@ -184,9 +174,7 @@ 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:
|
||||
|
||||
::
|
||||
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...
|
||||
@ -197,9 +185,7 @@ take zImage kernel and pass it to the fastboot client:
|
||||
OKAY [ -0.000s]
|
||||
finished. total time: 2.766s
|
||||
|
||||
and on the U-Boot side you should see:
|
||||
|
||||
::
|
||||
and on the U-Boot side you should see::
|
||||
|
||||
Starting download of 1847296 bytes
|
||||
........................................................
|
||||
@ -212,3 +198,9 @@ and on the U-Boot side you should see:
|
||||
OK
|
||||
|
||||
Starting kernel ...
|
||||
|
||||
References
|
||||
----------
|
||||
|
||||
.. [1] :doc:`fastboot-protocol`
|
||||
.. [2] https://developer.android.com/studio/releases/platform-tools
|
||||
14
doc/android/index.rst
Normal file
14
doc/android/index.rst
Normal file
@ -0,0 +1,14 @@
|
||||
.. SPDX-License-Identifier: GPL-2.0+
|
||||
|
||||
Android-specific doc
|
||||
====================
|
||||
|
||||
.. toctree::
|
||||
:maxdepth: 2
|
||||
|
||||
ab
|
||||
avb2
|
||||
bcb
|
||||
boot-image
|
||||
fastboot-protocol
|
||||
fastboot
|
||||
@ -86,6 +86,18 @@ organized in a vendor subdirectory.
|
||||
|
||||
board/index
|
||||
|
||||
Android-specific doc
|
||||
--------------------
|
||||
|
||||
These books provide information about booting the Android OS from U-Boot,
|
||||
manipulating Android images from U-Boot shell and discusses other
|
||||
Android-specific features available in U-Boot.
|
||||
|
||||
.. toctree::
|
||||
:maxdepth: 2
|
||||
|
||||
android/index
|
||||
|
||||
Indices and tables
|
||||
==================
|
||||
|
||||
|
||||
@ -8,7 +8,7 @@
|
||||
This tests Android Verified Boot 2.0 support in U-boot:
|
||||
|
||||
For additional details about how to build proper vbmeta partition
|
||||
check doc/android/avb2.txt
|
||||
check doc/android/avb2.rst
|
||||
|
||||
For configuration verification:
|
||||
- Corrupt boot partition and check for failure
|
||||
|
||||
Loading…
Reference in New Issue
Block a user