Merge tag 'v2023.07-rc6' into next

Prepare v2023.07-rc6

30 files changed, 4721 insertions, 3 deletions

diff --git a/doc/usage/cmd/bind.rst b/doc/usage/cmd/bind.rst
new file mode 100644
index 00000000000..1a5cffcb723
--- /dev/null
+++ b/doc/usage/cmd/bind.rst
@@ -0,0 +1,103 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+bind command
+============
+
+Synopsis
+--------
+
+::
+
+    bind <node path> <driver>
+    bind <class> <index> <driver>
+
+Description
+-----------
+
+The bind command is used to bind a device to a driver. This makes the
+device available in U-Boot.
+
+While binding to a *node path* typically provides a working device
+binding by parent node and driver may lead to a device that is only
+partially initialized.
+
+node path
+    path of the device's device-tree node
+
+class
+    device class name
+
+index
+    index of the parent device in the device class
+
+driver
+    device driver name
+
+Example
+-------
+
+Given a system with a real time clock device with device path */pl031@9010000*
+and using driver rtc-pl031 unbinding and binding of the device is demonstrated
+using the two alternative bind syntaxes.
+
+.. code-block::
+
+    => dm tree
+     Class     Index  Probed  Driver                Name
+    -----------------------------------------------------------
+     root          0  [ + ]   root_driver           root_driver
+    ...
+     rtc           0  [   ]   rtc-pl031             |-- pl031@9010000
+    ...
+    => fdt addr $fdtcontroladdr
+    Working FDT set to 7ed7fdb0
+    => fdt print
+    / {
+            interrupt-parent = <0x00008003>;
+            model = "linux,dummy-virt";
+            #size-cells = <0x00000002>;
+            #address-cells = <0x00000002>;
+            compatible = "linux,dummy-virt";
+    ...
+            pl031@9010000 {
+                    clock-names = "apb_pclk";
+                    clocks = <0x00008000>;
+                    interrupts = <0x00000000 0x00000002 0x00000004>;
+                    reg = <0x00000000 0x09010000 0x00000000 0x00001000>;
+                    compatible = "arm,pl031", "arm,primecell";
+            };
+    ...
+    }
+    => unbind /pl031@9010000
+    => date
+    Cannot find RTC: err=-19
+    => dm tree
+     Class     Index  Probed  Driver                Name
+    -----------------------------------------------------------
+     root          0  [ + ]   root_driver           root_driver
+    ...
+    => bind /pl031@9010000 rtc-pl031
+    => dm tree
+     Class     Index  Probed  Driver                Name
+    -----------------------------------------------------------
+     root          0  [ + ]   root_driver           root_driver
+    ...
+     rtc           0  [   ]   rtc-pl031             |-- pl031@9010000
+    => date
+    Date: 2023-06-22 (Thursday)    Time: 15:14:51
+    => unbind rtc 0 rtc-pl031
+    => bind root 0 rtc-pl031
+    => date
+    Date: 1980-08-19 (Tuesday)    Time: 14:45:30
+
+Obviously the device is not initialized correctly by the last bind command.
+
+Configuration
+-------------
+
+The bind command is only available if CONFIG_CMD_BIND=y.
+
+Return code
+-----------
+
+The return code $? is 0 (true) on success and 1 (false) on failure.
diff --git a/doc/usage/cmd/bootm.rst b/doc/usage/cmd/bootm.rst
new file mode 100644
index 00000000000..a7e5f6ce69a
--- /dev/null
+++ b/doc/usage/cmd/bootm.rst
@@ -0,0 +1,300 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+bootm command
+=============
+
+Synopsis
+--------
+
+::
+
+    bootm [fit_addr]#<conf>[#extra-conf]
+    bootm [[fit_addr]:<os_subimg>] [[<fit_addr2>]:<rd_subimg2>] [[<fit_addr3>]:<fdt_subimg>]
+
+    bootm <addr1> [[<addr2> [<addr3>]]    # Legacy boot
+
+Description
+-----------
+
+The *bootm* command is used to boot an Operating System. It has a large number
+of options depending on what needs to be booted.
+
+Note that the second form supports the first and/or second arguments to be
+omitted by using a hyphen '-' instead.
+
+fit_addr / fit_addr2 / fit_addr3
+    address of FIT to boot, defaults to CONFIG_SYS_LOAD_ADDR. See notes below.
+
+conf
+    configuration unit to boot (must be preceded by hash '#')
+
+extra-conf
+    extra configuration to boot. This is supported only for additional
+    devicetree overlays to apply on the base device tree supplied by the first
+    configuration unit.
+
+os_subimg
+    OS sub-image to boot (must be preceded by colon ':')
+
+rd_subimg
+    ramdisk sub-image to boot. Use a hyphen '-' if there is no ramdisk but an
+    FDT is needed.
+
+fdt_subimg
+    FDT sub-image to boot
+
+See below for legacy boot. Booting using :doc:`../fit/index` is recommended.
+
+Note on current image address
+-----------------------------
+
+When bootm is called without arguments, the image at current image address is
+booted. The current image address is the address set most recently by a load
+command, etc, and is by default equal to CONFIG_SYS_LOAD_ADDR. For example,
+consider the following commands::
+
+    tftp 200000 /tftpboot/kernel
+    bootm
+    # Last command is equivalent to:
+    # bootm 200000
+
+As shown above, with FIT the address portion of any argument
+can be omitted. If <addr3> is omitted, then it is assumed that image at
+<addr2> should be used. Similarly, when <addr2> is omitted, it is assumed that
+image at <addr1> should be used. If <addr1> is omitted, it is assumed that the
+current image address is to be used. For example, consider the following
+commands::
+
+    tftp 200000 /tftpboot/uImage
+    bootm :kernel-1
+    # Last command is equivalent to:
+    # bootm 200000:kernel-1
+
+    tftp 200000 /tftpboot/uImage
+    bootm 400000:kernel-1 :ramdisk-1
+    # Last command is equivalent to:
+    # bootm 400000:kernel-1 400000:ramdisk-1
+
+    tftp 200000 /tftpboot/uImage
+    bootm :kernel-1 400000:ramdisk-1 :fdt-1
+    # Last command is equivalent to:
+    # bootm 200000:kernel-1 400000:ramdisk-1 400000:fdt-1
+
+
+Legacy boot
+-----------
+
+U-Boot supports a legacy image format, enabled by `CONFIG_LEGACY_IMAGE_FORMAT`.
+This is not recommended as it is quite limited and insecure. Use
+:doc:`../fit/index` instead. It is documented here for old boards which still
+use it.
+
+Arguments are:
+
+addr1
+    address of legacy image to boot. If the image includes a second component
+    (ramdisk) it is used as well, unless the second parameter is hyphen '-'.
+
+addr2
+    address of legacy image to use as ramdisk
+
+addr3
+    address of legacy image to use as FDT
+
+
+Example syntax
+--------------
+
+This section provides various examples of possible usage::
+
+    1.  bootm       /* boot image at the current address, equivalent to 2,3,8 */
+
+This is equivalent to cases 2, 3 or 8, depending on the type of image at
+the current image address.
+
+Boot method: see cases 2,3,8
+
+Legacy uImage syntax
+~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    2.  bootm <addr1>            /* single image at <addr1> */
+
+Boot kernel image located at <addr1>.
+
+Boot method: non-FDT
+
+::
+
+    3.  bootm <addr1>            /* multi-image at <addr1>  */
+
+First and second components of the image at <addr1> are assumed to be a
+kernel and a ramdisk, respectively. The kernel is booted with initrd loaded
+with the ramdisk from the image.
+
+Boot method: depends on the number of components at <addr1>, and on whether
+U-Boot is compiled with OF support, which it should be.
+
+    ==================== ======================== ========================
+    Configuration        2 components             3 components
+                         (kernel, initrd)         (kernel, initrd, fdt)
+    ==================== ======================== ========================
+    #ifdef CONFIG_OF_*                   non-FDT                     FDT
+    #ifndef CONFIG_OF_*                  non-FDT                 non-FDT
+    ==================== ======================== ========================
+
+::
+
+    4.  bootm <addr1> -            /* multi-image at <addr1>  */
+
+Similar to case 3, but the kernel is booted without initrd.  Second
+component of the multi-image is irrelevant (it can be a dummy, 1-byte file).
+
+Boot method: see case 3
+
+::
+
+    5.  bootm <addr1> <addr2>        /* single image at <addr1> */
+
+Boot kernel image located at <addr1> with initrd loaded with ramdisk
+from the image at <addr2>.
+
+Boot method: non-FDT
+
+::
+
+    6.  bootm <addr1> <addr2> <addr3>   /* single image at <addr1> */
+
+<addr1> is the address of a kernel image, <addr2> is the address of a
+ramdisk image, and <addr3> is the address of a FDT binary blob.  Kernel is
+booted with initrd loaded with ramdisk from the image at <addr2>.
+
+Boot method: FDT
+
+::
+
+    7.  bootm <addr1> -      <addr3>   /* single image at <addr1> */
+
+<addr1> is the address of a kernel image and <addr3> is the address of
+a FDT binary blob. Kernel is booted without initrd.
+
+Boot method: FDT
+
+FIT syntax
+~~~~~~~~~~
+
+::
+
+    8.  bootm <addr1>
+
+Image at <addr1> is assumed to contain a default configuration, which
+is booted.
+
+Boot method: FDT or non-FDT, depending on whether the default configuration
+defines FDT
+
+::
+
+    9.  bootm [<addr1>]:<subimg1>
+
+Similar to case 2: boot kernel stored in <subimg1> from the image at
+address <addr1>.
+
+Boot method: non-FDT
+
+::
+
+    10. bootm [<addr1>]#<conf>[#<extra-conf[#...]]
+
+Boot configuration <conf> from the image at <addr1>.
+
+Boot method: FDT or non-FDT, depending on whether the configuration given
+defines FDT
+
+::
+
+    11. bootm [<addr1>]:<subimg1> [<addr2>]:<subimg2>
+
+Equivalent to case 5: boot kernel stored in <subimg1> from the image
+at <addr1> with initrd loaded with ramdisk <subimg2> from the image at
+<addr2>.
+
+Boot method: non-FDT
+
+::
+
+    12. bootm [<addr1>]:<subimg1> [<addr2>]:<subimg2> [<addr3>]:<subimg3>
+
+Equivalent to case 6: boot kernel stored in <subimg1> from the image
+at <addr1> with initrd loaded with ramdisk <subimg2> from the image at
+<addr2>, and pass FDT blob <subimg3> from the image at <addr3>.
+
+Boot method: FDT
+
+::
+
+    13. bootm [<addr1>]:<subimg1> [<addr2>]:<subimg2> <addr3>
+
+Similar to case 12, the difference being that <addr3> is the address
+of FDT binary blob that is to be passed to the kernel.
+
+Boot method: FDT
+
+::
+
+    14. bootm [<addr1>]:<subimg1> -              [<addr3>]:<subimg3>
+
+Equivalent to case 7: boot kernel stored in <subimg1> from the image
+at <addr1>, without initrd, and pass FDT blob <subimg3> from the image at
+<addr3>.
+
+Boot method: FDT
+
+    15. bootm [<addr1>]:<subimg1> -              <addr3>
+
+Similar to case 14, the difference being that <addr3> is the address
+of the FDT binary blob that is to be passed to the kernel.
+
+Boot method: FDT
+
+
+
+Example
+-------
+
+boot kernel "kernel-1" stored in a new uImage located at 200000::
+
+    bootm 200000:kernel-1
+
+boot configuration "cfg-1" from a new uImage located at 200000::
+
+    bootm 200000#cfg-1
+
+boot configuration "cfg-1" with extra "cfg-2" from a new uImage located
+at 200000::
+
+    bootm 200000#cfg-1#cfg-2
+
+boot "kernel-1" from a new uImage at 200000 with initrd "ramdisk-2" found in
+some other new uImage stored at address 800000::
+
+    bootm 200000:kernel-1 800000:ramdisk-2
+
+boot "kernel-2" from a new uImage at 200000, with initrd "ramdisk-1" and FDT
+"fdt-1", both stored in some other new uImage located at 800000::
+
+    bootm 200000:kernel-1 800000:ramdisk-1 800000:fdt-1
+
+boot kernel "kernel-2" with initrd "ramdisk-2", both stored in a new uImage
+at address 200000, with a raw FDT blob stored at address 600000::
+
+    bootm 200000:kernel-2 200000:ramdisk-2 600000
+
+boot kernel "kernel-2" from new uImage at 200000 with FDT "fdt-1" from the
+same new uImage::
+
+    bootm 200000:kernel-2 - 200000:fdt-1
+
+.. sectionauthor:: Bartlomiej Sieka <[email protected]>
+.. sectionauthor:: Simon Glass <[email protected]>
diff --git a/doc/usage/cmd/imxtract.rst b/doc/usage/cmd/imxtract.rst
new file mode 100644
index 00000000000..eb64b1cefab
--- /dev/null
+++ b/doc/usage/cmd/imxtract.rst
@@ -0,0 +1,81 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+imxtract command
+================
+
+Synopsis
+--------
+
+::
+
+    imxtract addr part [dest]
+    imxtract addr uname [dest]
+
+Description
+-----------
+
+The imxtract command is used to extract a part of a multi-image file.
+
+Two different file formats are supported:
+
+* FIT images
+* legacy U-Boot images
+
+addr
+    Address of the multi-image file from which a part shall be extracted
+
+part
+    Index (hexadecimal) of the part of a legacy U-Boot image to be extracted
+
+uname
+    Name of the part of a FIT image to be extracted
+
+dest
+    Destination address (defaults to 0x0)
+
+The value of environment variable *verify* controls if the hashes and
+signatures of FIT images or the check sums of legacy U-Boot images are checked.
+To enable checking set *verify* to one of the values *1*, *yes*, *true*.
+(Actually only the first letter is checked disregarding the case.)
+
+To list the parts of an image the *iminfo* command can be used.
+
+Examples
+--------
+
+With verify=no incorrect hashes, signatures, or check sums don't stop the
+extraction. But correct hashes are still indicated in the output
+(here: md5, sha1).
+
+.. code-block:: console
+
+    => setenv verify no
+    => imxtract $loadaddr kernel-1 $kernel_addr_r
+    ## Copying 'kernel-1' subimage from FIT image at 40200000 ...
+    md5+ sha1+    Loading part 0 ... OK
+    =>
+
+With verify=yes incorrect hashes, signatures, or check sums stop the extraction.
+
+.. code-block:: console
+
+    => setenv verify yes
+    => imxtract $loadaddr kernel-1 $kernel_addr_r
+    ## Copying 'kernel-1' subimage from FIT image at 40200000 ...
+    md5 error!
+    Bad hash value for 'hash-1' hash node in 'kernel-1' image node
+    Bad Data Hash
+    =>
+
+Configuration
+-------------
+
+The imxtract command is only available if CONFIG_CMD_XIMG=y. Support for FIT
+images requires CONFIG_FIT=y. Support for legacy U-Boot images requires
+CONFIG_LEGACY_IMAGE_FORMAT=y.
+
+Return value
+------------
+
+On success the return value $? of the command is 0 (true). On failure the
+return value is 1 (false).
diff --git a/doc/usage/cmd/loadb.rst b/doc/usage/cmd/loadb.rst
index b37d1d7b596..0464b1f41ce 100644
--- a/doc/usage/cmd/loadb.rst
+++ b/doc/usage/cmd/loadb.rst
@@ -13,7 +13,7 @@ Synopsis
 Description
 -----------
 
-The loady command is used to transfer a file to the device via the serial line
+The loadb command is used to transfer a file to the device via the serial line
 using the Kermit protocol.
 
 The number of transferred bytes is saved in environment variable filesize.
diff --git a/doc/usage/cmd/loads.rst b/doc/usage/cmd/loads.rst
new file mode 100644
index 00000000000..e4cb063df6d
--- /dev/null
+++ b/doc/usage/cmd/loads.rst
@@ -0,0 +1,96 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+loads command
+=============
+
+Synopsis
+--------
+
+::
+
+    loads [offset [baud]]
+
+Description
+-----------
+
+The loads command is used to transfer a file to the device via the serial line
+using the Motorola S-record file format.
+
+offset
+    offset added to the addresses in the S-record file
+
+baud
+    baud rate to use for download. This parameter is only available if
+    CONFIG_SYS_LOADS_BAUD_CHANGE=y
+
+Example
+-------
+
+As example file to be transferred we use a script printing 'hello s-record'.
+Here are the commands to create the S-record file:
+
+.. code-block:: bash
+
+    $ echo 'echo hello s-record' > script.txt
+    $ mkimage -T script -d script.txt script.scr
+    Image Name:
+    Created:      Sun Jun 25 10:35:02 2023
+    Image Type:   PowerPC Linux Script (gzip compressed)
+    Data Size:    28 Bytes = 0.03 KiB = 0.00 MiB
+    Load Address: 00000000
+    Entry Point:  00000000
+    Contents:
+       Image 0: 20 Bytes = 0.02 KiB = 0.00 MiB
+    $ srec_cat script.scr -binary -CRLF -Output script.srec
+    $ echo -e "S9030000FC\r" >> script.srec
+    $ cat script.srec
+    S0220000687474703A2F2F737265636F72642E736F75726365666F7267652E6E65742F1D
+    S1230000270519566D773EB6649815E30000001700000000000000003DE3D97005070601E2
+    S12300200000000000000000000000000000000000000000000000000000000000000000BC
+    S11A00400000000F0000000068656C6C6F20732D7265636F72640A39
+    S5030003F9
+    S9030000FC
+    $
+
+The load address in the first S1 record is 0x0000.
+
+The terminal emulation program picocom is invoked with *cat* as the send
+command to transfer the file.
+
+.. code-block::
+
+    picocom --send-cmd 'cat' --baud 115200 /dev/ttyUSB0
+
+After entering the *loads* command the key sequence <CTRL-A><CTRL-S> is used to
+let picocom prompt for the file name. Picocom invokes the program *cat* for the
+file transfer. The loaded script is executed using the *source* command.
+
+.. code-block::
+
+    => loads $scriptaddr
+    ## Ready for S-Record download ...
+
+    *** file: script.srec
+    $ cat script.srec
+
+    *** exit status: 0 ***
+
+    ## First Load Addr = 0x4FC00000
+    ## Last  Load Addr = 0x4FC0005B
+    ## Total Size      = 0x0000005C = 92 Bytes
+    ## Start Addr      = 0x00000000
+    => source $scriptaddr
+    ## Executing script at 4fc00000
+    hello s-record
+    =>
+
+Configuration
+-------------
+
+The command is only available if CONFIG_CMD_LOADS=y. The parameter to set the
+baud rate is only available if CONFIG_SYS_LOADS_BAUD_CHANGE=y
+
+Return value
+------------
+
+The return value $? is 0 (true) on success, 1 (false) otherwise.
diff --git a/doc/usage/cmd/saves.rst b/doc/usage/cmd/saves.rst
new file mode 100644
index 00000000000..5823f883790
--- /dev/null
+++ b/doc/usage/cmd/saves.rst
@@ -0,0 +1,88 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+saves command
+=============
+
+Synopsis
+--------
+
+::
+
+    saves [offset [size [baud]]]
+
+Description
+-----------
+
+The *saves* command is used to transfer a file from the device via the serial
+line using the Motorola S-record file format.
+
+offset
+    start address of memory area to save, defaults to 0x0
+
+size
+    size of memory area to save, defaults to 0x0
+
+baud
+    baud rate to use for upload. This parameter is only available if
+    CONFIG_SYS_LOADS_BAUD_CHANGE=y
+
+Example
+-------
+
+In the example the *screen* command is used to connect to the U-Boot serial
+console.
+
+In a first screen session a file is loaded from the SD-card and the *saves*
+command is invoked. <CTRL+A><k> is used to kill the screen session.
+
+A new screen session is started which logs the output to a file and the
+<ENTER> key is hit to start the file output. <CTRL+A><k> is issued to kill the
+screen session.
+
+The log file is converted to a binary file using the *srec_cat* command.
+A negative offset of -1337982976 (= -0x4c000000) is applied to compensate for
+the offset used in the *saves* command.
+
+.. code-block::
+
+    $ screen /dev/ttyUSB0 115200
+    => echo $scriptaddr
+    0x4FC00000
+    => load mmc 0:1 $scriptaddr boot.txt
+    124 bytes read in 1 ms (121.1 KiB/s)
+    => saves $scriptaddr $filesize
+    ## Ready for S-Record upload, press ENTER to proceed ...
+    Really kill this window [y/n]
+    $ screen -Logfile out.srec -L /dev/ttyUSB0 115200
+    S0030000FC
+    S3154FC00000736574656E76206175746F6C6F616420AD
+    S3154FC000106E6F0A646863700A6C6F6164206D6D633E
+    S3154FC0002020303A3120246664745F616464725F72B3
+    S3154FC00030206474620A6C6F6164206D6D6320303AC0
+    S3154FC000403120246B65726E656C5F616464725F72DA
+    S3154FC0005020736E702E6566690A626F6F74656669C6
+    S3154FC0006020246B65726E656C5F616464725F7220CB
+    S3114FC00070246664745F616464725F720A38
+    S70500000000FA
+    ## S-Record upload complete
+    =>
+    Really kill this window [y/n]
+    $ srec_cat out.srec -offset -1337982976 -Output out.txt -binary 2>/dev/null
+    $ cat out.txt
+    setenv autoload no
+    dhcp
+    load mmc 0:1 $fdt_addr_r dtb
+    load mmc 0:1 $kernel_addr_r snp.efi
+    bootefi $kernel_addr_r $fdt_addr_r
+    $
+
+Configuration
+-------------
+
+The command is only available if CONFIG_CMD_SAVES=y. The parameter to set the
+baud rate is only available if CONFIG_SYS_LOADS_BAUD_CHANGE=y
+
+Return value
+------------
+
+The return value $? is 0 (true) on success, 1 (false) otherwise.
diff --git a/doc/usage/cmd/source.rst b/doc/usage/cmd/source.rst
index a5c5204a28b..697f644745b 100644
--- a/doc/usage/cmd/source.rst
+++ b/doc/usage/cmd/source.rst
@@ -22,7 +22,7 @@ Two formats for script files exist:
 * Flat Image Tree (FIT)
 
 The benefit of the FIT images is that they can be signed and verifed as
-decribed in :download:`signature.txt <../../uImage.FIT/signature.txt>`.
+described in :doc:`../fit/signature`.
 
 Both formats can be created with the mkimage tool.
 
diff --git a/doc/usage/cmd/unbind.rst b/doc/usage/cmd/unbind.rst
new file mode 100644
index 00000000000..594e4f06892
--- /dev/null
+++ b/doc/usage/cmd/unbind.rst
@@ -0,0 +1,95 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+unbind command
+==============
+
+Synopsis
+--------
+
+::
+
+    unbind <node path>
+    unbind <class> <index>
+    unbind <class> <index> <driver>
+
+Description
+-----------
+
+The unbind command is used to unbind a device from a driver. This makes the
+device unavailable in U-Boot.
+
+node path
+    path of the device's device-tree node
+
+class
+    device class name
+
+index
+    index of the device in the device class
+
+driver
+    device driver name
+
+Example
+-------
+
+Given a system with a real time clock device with device path */pl031@9010000*
+and using driver rtc-pl031 unbinding and binding of the device is demonstrated
+using the three alternative unbind syntaxes.
+
+.. code-block::
+
+    => dm tree
+     Class     Index  Probed  Driver                Name
+    -----------------------------------------------------------
+     root          0  [ + ]   root_driver           root_driver
+    ...
+     rtc           0  [   ]   rtc-pl031             |-- pl031@9010000
+    ...
+    => fdt addr $fdtcontroladdr
+    Working FDT set to 7ed7fdb0
+    => fdt print
+    / {
+            interrupt-parent = <0x00008003>;
+            model = "linux,dummy-virt";
+            #size-cells = <0x00000002>;
+            #address-cells = <0x00000002>;
+            compatible = "linux,dummy-virt";
+    ...
+            pl031@9010000 {
+                    clock-names = "apb_pclk";
+                    clocks = <0x00008000>;
+                    interrupts = <0x00000000 0x00000002 0x00000004>;
+                    reg = <0x00000000 0x09010000 0x00000000 0x00001000>;
+                    compatible = "arm,pl031", "arm,primecell";
+            };
+    ...
+    }
+    => unbind /pl031@9010000
+    => dm tree
+     Class     Index  Probed  Driver                Name
+    -----------------------------------------------------------
+     root          0  [ + ]   root_driver           root_driver
+    ...
+    => unbind /pl031@9010000
+    Cannot find a device with path /pl031@9010000
+    => bind /pl031@9010000 rtc-pl031
+    => dm tree
+     Class     Index  Probed  Driver                Name
+    -----------------------------------------------------------
+     root          0  [ + ]   root_driver           root_driver
+    ...
+     rtc           0  [   ]   rtc-pl031             |-- pl031@9010000
+    => unbind rtc 0
+    => bind /pl031@9010000 rtc-pl031
+    => unbind rtc 0 rtc-pl031
+
+Configuration
+-------------
+
+The unbind command is only available if CONFIG_CMD_BIND=y.
+
+Return code
+-----------
+
+The return code $? is 0 (true) on success and 1 (false) on failure.
diff --git a/doc/usage/fit/beaglebone_vboot.rst b/doc/usage/fit/beaglebone_vboot.rst
new file mode 100644
index 00000000000..0580ee10bdc
--- /dev/null
+++ b/doc/usage/fit/beaglebone_vboot.rst
@@ -0,0 +1,612 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Verified Boot on the Beaglebone Black
+=====================================
+
+Introduction
+------------
+
+Before reading this, please read :doc:`verified-boot` and :doc:`signature`.
+These instructions are for mainline U-Boot from v2014.07 onwards.
+
+There is quite a bit of documentation in this directory describing how
+verified boot works in U-Boot. There is also a test which runs through the
+entire process of signing an image and running U-Boot (sandbox) to check it.
+However, it might be useful to also have an example on a real board.
+
+Beaglebone Black is a fairly common board so seems to be a reasonable choice
+for an example of how to enable verified boot using U-Boot.
+
+First a note that may to help avoid confusion. U-Boot and Linux both use
+device tree. They may use the same device tree source, but it is seldom useful
+for them to use the exact same binary from the same place. More typically,
+U-Boot has its device tree packaged with it, and the kernel's device tree is
+packaged with the kernel. In particular this is important with verified boot,
+since U-Boot's device tree must be immutable. If it can be changed then the
+public keys can be changed and verified boot is useless. An attacker can
+simply generate a new key and put his public key into U-Boot so that
+everything verifies. On the other hand the kernel's device tree typically
+changes when the kernel changes, so it is useful to package an updated device
+tree with the kernel binary. U-Boot supports the latter with its flexible FIT
+format (Flat Image Tree).
+
+
+Overview
+--------
+
+The steps are roughly as follows:
+
+#. Build U-Boot for the board, with the verified boot options enabled.
+
+#. Obtain a suitable Linux kernel
+
+#. Create a Image Tree Source file (ITS) file describing how you want the
+   kernel to be packaged, compressed and signed.
+
+#. Create a key pair
+
+#. Sign the kernel
+
+#. Put the public key into U-Boot's image
+
+#. Put U-Boot and the kernel onto the board
+
+#. Try it
+
+
+Step 1: Build U-Boot
+--------------------
+
+a. Set up the environment variable to point to your toolchain. You will need
+   this for U-Boot and also for the kernel if you build it. For example if you
+   installed a Linaro version manually it might be something like::
+
+       export CROSS_COMPILE=/opt/linaro/gcc-linaro-arm-linux-gnueabihf-4.8-2013.08_linux/bin/arm-linux-gnueabihf-
+
+   or if you just installed gcc-arm-linux-gnueabi then it might be::
+
+       export CROSS_COMPILE=arm-linux-gnueabi-
+
+b. Configure and build U-Boot with verified boot enabled::
+
+    export UBOOT=/path/to/u-boot
+    cd $UBOOT
+    # You can add -j10 if you have 10 CPUs to make it faster
+    make O=b/am335x_boneblack_vboot am335x_boneblack_vboot_config all
+    export UOUT=$UBOOT/b/am335x_boneblack_vboot
+
+c. You will now have a U-Boot image::
+
+    file b/am335x_boneblack_vboot/u-boot-dtb.img
+    b/am335x_boneblack_vboot/u-boot-dtb.img: u-boot legacy uImage,
+      U-Boot 2014.07-rc2-00065-g2f69f8, Firmware/ARM, Firmware Image
+      (Not compressed), 395375 bytes, Sat May 31 16:19:04 2014,
+      Load Address: 0x80800000, Entry Point: 0x00000000,
+      Header CRC: 0x0ABD6ACA, Data CRC: 0x36DEF7E4
+
+
+Step 2: Build Linux
+--------------------
+
+a. Find the kernel image ('Image') and device tree (.dtb) file you plan to
+   use. In our case it is am335x-boneblack.dtb and it is built with the kernel.
+   At the time of writing an SD Boot image can be obtained from here::
+
+       http://www.elinux.org/Beagleboard:Updating_The_Software#Image_For_Booting_From_microSD
+
+   You can write this to an SD card and then mount it to extract the kernel and
+   device tree files.
+
+   You can also build a kernel. Instructions for this are are here::
+
+       http://elinux.org/Building_BBB_Kernel
+
+   or you can use your favourite search engine. Following these instructions
+   produces a kernel Image and device tree files. For the record the steps
+   were::
+
+        export KERNEL=/path/to/kernel
+        cd $KERNEL
+        git clone git://github.com/beagleboard/kernel.git .
+        git checkout v3.14
+        ./patch.sh
+        cp configs/beaglebone kernel/arch/arm/configs/beaglebone_defconfig
+        cd kernel
+        make beaglebone_defconfig
+        make uImage dtbs   # -j10 if you have 10 CPUs
+        export OKERNEL=$KERNEL/kernel/arch/arm/boot
+
+b. You now have the 'Image' and 'am335x-boneblack.dtb' files needed to boot.
+
+
+Step 3: Create the ITS
+----------------------
+
+Set up a directory for your work::
+
+   export WORK=/path/to/dir
+   cd $WORK
+
+Put this into a file in that directory called sign.its::
+
+    /dts-v1/;
+
+    / {
+        description = "Beaglebone black";
+        #address-cells = <1>;
+
+        images {
+            kernel {
+                data = /incbin/("Image.lzo");
+                type = "kernel";
+                arch = "arm";
+                os = "linux";
+                compression = "lzo";
+                load = <0x80008000>;
+                entry = <0x80008000>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+            fdt-1 {
+                description = "beaglebone-black";
+                data = /incbin/("am335x-boneblack.dtb");
+                type = "flat_dt";
+                arch = "arm";
+                compression = "none";
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+        };
+        configurations {
+            default = "conf-1";
+            conf-1 {
+                kernel = "kernel";
+                fdt = "fdt-1";
+                signature-1 {
+                    algo = "sha1,rsa2048";
+                    key-name-hint = "dev";
+                    sign-images = "fdt", "kernel";
+                };
+            };
+        };
+    };
+
+
+The explanation for this is all in the documentation you have already read.
+But briefly it packages a kernel and device tree, and provides a single
+configuration to be signed with a key named 'dev'. The kernel is compressed
+with LZO to make it smaller.
+
+
+Step 4: Create a key pair
+-------------------------
+
+See :doc:`signature` for details on this step::
+
+   cd $WORK
+   mkdir keys
+   openssl genrsa -F4 -out keys/dev.key 2048
+   openssl req -batch -new -x509 -key keys/dev.key -out keys/dev.crt
+
+Note: keys/dev.key contains your private key and is very secret. If anyone
+gets access to that file they can sign kernels with it. Keep it secure.
+
+
+Step 5: Sign the kernel
+-----------------------
+
+We need to use mkimage (which was built when you built U-Boot) to package the
+Linux kernel into a FIT (Flat Image Tree, a flexible file format that U-Boot
+can load) using the ITS file you just created.
+
+At the same time we must put the public key into U-Boot device tree, with the
+'required' property, which tells U-Boot that this key must be verified for the
+image to be valid. You will make this key available to U-Boot for booting in
+step 6::
+
+   ln -s $OKERNEL/dts/am335x-boneblack.dtb
+   ln -s $OKERNEL/Image
+   ln -s $UOUT/u-boot-dtb.img
+   cp $UOUT/arch/arm/dts/am335x-boneblack.dtb am335x-boneblack-pubkey.dtb
+   lzop Image
+   $UOUT/tools/mkimage -f sign.its -K am335x-boneblack-pubkey.dtb -k keys -r image.fit
+
+You should see something like this::
+
+    FIT description: Beaglebone black
+    Created:         Sun Jun  1 12:50:30 2014
+     Image 0 (kernel)
+      Description:  unavailable
+      Created:      Sun Jun  1 12:50:30 2014
+      Type:         Kernel Image
+      Compression:  lzo compressed
+      Data Size:    7790938 Bytes = 7608.34 kB = 7.43 MB
+      Architecture: ARM
+      OS:           Linux
+      Load Address: 0x80008000
+      Entry Point:  0x80008000
+      Hash algo:    sha1
+      Hash value:   c94364646427e10f423837e559898ef02c97b988
+     Image 1 (fdt-1)
+      Description:  beaglebone-black
+      Created:      Sun Jun  1 12:50:30 2014
+      Type:         Flat Device Tree
+      Compression:  uncompressed
+      Data Size:    31547 Bytes = 30.81 kB = 0.03 MB
+      Architecture: ARM
+      Hash algo:    sha1
+      Hash value:   cb09202f889d824f23b8e4404b781be5ad38a68d
+     Default Configuration: 'conf-1'
+     Configuration 0 (conf-1)
+      Description:  unavailable
+      Kernel:       kernel
+      FDT:          fdt-1
+
+
+Now am335x-boneblack-pubkey.dtb contains the public key and image.fit contains
+the signed kernel. Jump to step 6 if you like, or continue reading to increase
+your understanding.
+
+You can also run fit_check_sign to check it::
+
+   $UOUT/tools/fit_check_sign -f image.fit -k am335x-boneblack-pubkey.dtb
+
+which results in::
+
+    Verifying Hash Integrity ... sha1,rsa2048:dev+
+    ## Loading kernel from FIT Image at 7fc6ee469000 ...
+       Using 'conf-1' configuration
+       Verifying Hash Integrity ...
+    sha1,rsa2048:dev+
+    OK
+
+       Trying 'kernel' kernel subimage
+         Description:  unavailable
+         Created:      Sun Jun  1 12:50:30 2014
+         Type:         Kernel Image
+         Compression:  lzo compressed
+         Data Size:    7790938 Bytes = 7608.34 kB = 7.43 MB
+         Architecture: ARM
+         OS:           Linux
+         Load Address: 0x80008000
+         Entry Point:  0x80008000
+         Hash algo:    sha1
+         Hash value:   c94364646427e10f423837e559898ef02c97b988
+       Verifying Hash Integrity ...
+    sha1+
+    OK
+
+    Unimplemented compression type 4
+    ## Loading fdt from FIT Image at 7fc6ee469000 ...
+       Using 'conf-1' configuration
+       Trying 'fdt-1' fdt subimage
+         Description:  beaglebone-black
+         Created:      Sun Jun  1 12:50:30 2014
+         Type:         Flat Device Tree
+         Compression:  uncompressed
+         Data Size:    31547 Bytes = 30.81 kB = 0.03 MB
+         Architecture: ARM
+         Hash algo:    sha1
+         Hash value:   cb09202f889d824f23b8e4404b781be5ad38a68d
+       Verifying Hash Integrity ...
+    sha1+
+    OK
+
+       Loading Flat Device Tree ... OK
+
+    ## Loading ramdisk from FIT Image at 7fc6ee469000 ...
+       Using 'conf-1' configuration
+    Could not find subimage node
+
+    Signature check OK
+
+
+At the top, you see "sha1,rsa2048:dev+". This means that it checked an RSA key
+of size 2048 bits using SHA1 as the hash algorithm. The key name checked was
+'dev' and the '+' means that it verified. If it showed '-' that would be bad.
+
+Once the configuration is verified it is then possible to rely on the hashes
+in each image referenced by that configuration. So fit_check_sign goes on to
+load each of the images. We have a kernel and an FDT but no ramkdisk. In each
+case fit_check_sign checks the hash and prints sha1+ meaning that the SHA1
+hash verified. This means that none of the images has been tampered with.
+
+There is a test in test/vboot which uses U-Boot's sandbox build to verify that
+the above flow works.
+
+But it is fun to do this by hand, so you can load image.fit into a hex editor
+like ghex, and change a byte in the kernel::
+
+    $UOUT/tools/fit_info -f image.fit -n /images/kernel -p data
+    NAME: kernel
+    LEN: 7790938
+    OFF: 168
+
+This tells us that the kernel starts at byte offset 168 (decimal) in image.fit
+and extends for about 7MB. Try changing a byte at 0x2000 (say) and run
+fit_check_sign again. You should see something like::
+
+    Verifying Hash Integrity ... sha1,rsa2048:dev+
+    ## Loading kernel from FIT Image at 7f5a39571000 ...
+       Using 'conf-1' configuration
+       Verifying Hash Integrity ...
+    sha1,rsa2048:dev+
+    OK
+
+       Trying 'kernel' kernel subimage
+         Description:  unavailable
+         Created:      Sun Jun  1 13:09:21 2014
+         Type:         Kernel Image
+         Compression:  lzo compressed
+         Data Size:    7790938 Bytes = 7608.34 kB = 7.43 MB
+         Architecture: ARM
+         OS:           Linux
+         Load Address: 0x80008000
+         Entry Point:  0x80008000
+         Hash algo:    sha1
+         Hash value:   c94364646427e10f423837e559898ef02c97b988
+       Verifying Hash Integrity ...
+    sha1 error
+    Bad hash value for 'hash-1' hash node in 'kernel' image node
+    Bad Data Hash
+
+    ## Loading fdt from FIT Image at 7f5a39571000 ...
+       Using 'conf-1' configuration
+       Trying 'fdt-1' fdt subimage
+         Description:  beaglebone-black
+         Created:      Sun Jun  1 13:09:21 2014
+         Type:         Flat Device Tree
+         Compression:  uncompressed
+         Data Size:    31547 Bytes = 30.81 kB = 0.03 MB
+         Architecture: ARM
+         Hash algo:    sha1
+         Hash value:   cb09202f889d824f23b8e4404b781be5ad38a68d
+       Verifying Hash Integrity ...
+    sha1+
+    OK
+
+       Loading Flat Device Tree ... OK
+
+    ## Loading ramdisk from FIT Image at 7f5a39571000 ...
+       Using 'conf-1' configuration
+    Could not find subimage node
+
+    Signature check Bad (error 1)
+
+
+It has detected the change in the kernel.
+
+You can also be sneaky and try to switch images, using the libfdt utilities
+that come with dtc (package name is device-tree-compiler but you will need a
+recent version like 1.4::
+
+    dtc -v
+    Version: DTC 1.4.0
+
+First we can check which nodes are actually hashed by the configuration::
+
+    $ fdtget -l image.fit /
+    images
+    configurations
+
+    $ fdtget -l image.fit /configurations
+    conf-1
+    fdtget -l image.fit /configurations/conf-1
+    signature-1
+
+    $ fdtget -p image.fit /configurations/conf-1/signature-1
+    hashed-strings
+    hashed-nodes
+    timestamp
+    signer-version
+    signer-name
+    value
+    algo
+    key-name-hint
+    sign-images
+
+    $ fdtget image.fit /configurations/conf-1/signature-1 hashed-nodes
+    / /configurations/conf-1 /images/fdt-1 /images/fdt-1/hash /images/kernel /images/kernel/hash-1
+
+This gives us a bit of a look into the signature that mkimage added. Note you
+can also use fdtdump to list the entire device tree.
+
+Say we want to change the kernel that this configuration uses
+(/images/kernel). We could just put a new kernel in the image, but we will
+need to change the hash to match. Let's simulate that by changing a byte of
+the hash::
+
+    fdtget -tx image.fit /images/kernel/hash-1 value
+    c9436464 6427e10f 423837e5 59898ef0 2c97b988
+    fdtput -tx image.fit /images/kernel/hash-1 value c9436464 6427e10f 423837e5 59898ef0 2c97b981
+
+Now check it again::
+
+    $UOUT/tools/fit_check_sign -f image.fit -k am335x-boneblack-pubkey.dtb
+    Verifying Hash Integrity ... sha1,rsa2048:devrsa_verify_with_keynode: RSA failed to verify: -13
+    rsa_verify_with_keynode: RSA failed to verify: -13
+    -
+    Failed to verify required signature 'key-dev'
+    Signature check Bad (error 1)
+
+This time we don't even get as far as checking the images, since the
+configuration signature doesn't match. We can't change any hashes without the
+signature check noticing. The configuration is essentially locked. U-Boot has
+a public key for which it requires a match, and will not permit the use of any
+configuration that does not match that public key. The only way the
+configuration will match is if it was signed by the matching private key.
+
+It would also be possible to add a new signature node that does match your new
+configuration. But that won't work since you are not allowed to change the
+configuration in any way. Try it with a fresh (valid) image if you like by
+running the mkimage link again. Then::
+
+    fdtput -p image.fit /configurations/conf-1/signature-1 value fred
+    $UOUT/tools/fit_check_sign -f image.fit -k am335x-boneblack-pubkey.dtb
+    Verifying Hash Integrity ... -
+    sha1,rsa2048:devrsa_verify_with_keynode: RSA failed to verify: -13
+    rsa_verify_with_keynode: RSA failed to verify: -13
+    -
+    Failed to verify required signature 'key-dev'
+    Signature check Bad (error 1)
+
+
+Of course it would be possible to add an entirely new configuration and boot
+with that, but it still needs to be signed, so it won't help.
+
+
+6. Put the public key into U-Boot's image
+-----------------------------------------
+
+Having confirmed that the signature is doing its job, let's try it out in
+U-Boot on the board. U-Boot needs access to the public key corresponding to
+the private key that you signed with so that it can verify any kernels that
+you sign::
+
+    cd $UBOOT
+    make O=b/am335x_boneblack_vboot EXT_DTB=${WORK}/am335x-boneblack-pubkey.dtb
+
+Here we are overriding the normal device tree file with our one, which
+contains the public key.
+
+Now you have a special U-Boot image with the public key. It can verify can
+kernel that you sign with the private key as in step 5.
+
+If you like you can take a look at the public key information that mkimage
+added to U-Boot's device tree::
+
+    fdtget -p am335x-boneblack-pubkey.dtb /signature/key-dev
+    required
+    algo
+    rsa,r-squared
+    rsa,modulus
+    rsa,n0-inverse
+    rsa,num-bits
+    key-name-hint
+
+This has information about the key and some pre-processed values which U-Boot
+can use to verify against it. These values are obtained from the public key
+certificate by mkimage, but require quite a bit of code to generate. To save
+code space in U-Boot, the information is extracted and written in raw form for
+U-Boot to easily use. The same mechanism is used in Google's Chrome OS.
+
+Notice the 'required' property. This marks the key as required - U-Boot will
+not boot any image that does not verify against this key.
+
+
+7. Put U-Boot and the kernel onto the board
+-------------------------------------------
+
+The method here varies depending on how you are booting. For this example we
+are booting from an micro-SD card with two partitions, one for U-Boot and one
+for Linux. Put it into your machine and write U-Boot and the kernel to it.
+Here the card is /dev/sde::
+
+    cd $WORK
+    export UDEV=/dev/sde1   # Change thes two lines to the correct device
+    export KDEV=/dev/sde2
+    sudo mount $UDEV /mnt/tmp && sudo cp $UOUT/u-boot-dtb.img /mnt/tmp/u-boot.img  && sleep 1 && sudo umount $UDEV
+    sudo mount $KDEV /mnt/tmp && sudo cp $WORK/image.fit /mnt/tmp/boot/image.fit && sleep 1 && sudo umount $KDEV
+
+
+8. Try it
+---------
+
+Boot the board using the commands below::
+
+    setenv bootargs console=ttyO0,115200n8 quiet root=/dev/mmcblk0p2 ro rootfstype=ext4 rootwait
+    ext2load mmc 0:2 82000000 /boot/image.fit
+    bootm 82000000
+
+You should then see something like this::
+
+    U-Boot# setenv bootargs console=ttyO0,115200n8 quiet root=/dev/mmcblk0p2 ro rootfstype=ext4 rootwait
+    U-Boot# ext2load mmc 0:2 82000000 /boot/image.fit
+    7824930 bytes read in 589 ms (12.7 MiB/s)
+    U-Boot# bootm 82000000
+    ## Loading kernel from FIT Image at 82000000 ...
+       Using 'conf-1' configuration
+       Verifying Hash Integrity ... sha1,rsa2048:dev+ OK
+       Trying 'kernel' kernel subimage
+         Description:  unavailable
+         Created:      2014-06-01  19:32:54 UTC
+         Type:         Kernel Image
+         Compression:  lzo compressed
+         Data Start:   0x820000a8
+         Data Size:    7790938 Bytes = 7.4 MiB
+         Architecture: ARM
+         OS:           Linux
+         Load Address: 0x80008000
+         Entry Point:  0x80008000
+         Hash algo:    sha1
+         Hash value:   c94364646427e10f423837e559898ef02c97b988
+       Verifying Hash Integrity ... sha1+ OK
+    ## Loading fdt from FIT Image at 82000000 ...
+       Using 'conf-1' configuration
+       Trying 'fdt-1' fdt subimage
+         Description:  beaglebone-black
+         Created:      2014-06-01  19:32:54 UTC
+         Type:         Flat Device Tree
+         Compression:  uncompressed
+         Data Start:   0x8276e2ec
+         Data Size:    31547 Bytes = 30.8 KiB
+         Architecture: ARM
+         Hash algo:    sha1
+         Hash value:   cb09202f889d824f23b8e4404b781be5ad38a68d
+       Verifying Hash Integrity ... sha1+ OK
+       Booting using the fdt blob at 0x8276e2ec
+       Uncompressing Kernel Image ... OK
+       Loading Device Tree to 8fff5000, end 8ffffb3a ... OK
+
+    Starting kernel ...
+
+    [    0.582377] omap_init_mbox: hwmod doesn't have valid attrs
+    [    2.589651] musb-hdrc musb-hdrc.0.auto: Failed to request rx1.
+    [    2.595830] musb-hdrc musb-hdrc.0.auto: musb_init_controller failed with status -517
+    [    2.606470] musb-hdrc musb-hdrc.1.auto: Failed to request rx1.
+    [    2.612723] musb-hdrc musb-hdrc.1.auto: musb_init_controller failed with status -517
+    [    2.940808] drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
+    [    7.248889] libphy: PHY 4a101000.mdio:01 not found
+    [    7.253995] net eth0: phy 4a101000.mdio:01 not found on slave 1
+    systemd-fsck[83]: Angstrom: clean, 50607/218160 files, 306348/872448 blocks
+
+    .---O---.
+    |       |                  .-.           o o
+    |   |   |-----.-----.-----.| |   .----..-----.-----.
+    |       |     | __  |  ---'| '--.|  .-'|     |     |
+    |   |   |  |  |     |---  ||  --'|  |  |  '  | | | |
+    '---'---'--'--'--.  |-----''----''--'  '-----'-'-'-'
+                    -'  |
+                    '---'
+
+    The Angstrom Distribution beaglebone ttyO0
+
+    Angstrom v2012.12 - Kernel 3.14.1+
+
+    beaglebone login:
+
+At this point your kernel has been verified and you can be sure that it is one
+that you signed. As an exercise, try changing image.fit as in step 5 and see
+what happens.
+
+
+Further Improvements
+--------------------
+
+Several of the steps here can be easily automated. In particular it would be
+capital if signing and packaging a kernel were easy, perhaps a simple make
+target in the kernel.
+
+Some mention of how to use multiple .dtb files in a FIT might be useful.
+
+U-Boot's verified boot mechanism has not had a robust and independent security
+review. Such a review should look at the implementation and its resistance to
+attacks.
+
+Perhaps the verified boot feature could be integrated into the Amstrom
+distribution.
+
+
+.. sectionauthor:: Simon Glass <[email protected]>, 2-June-14
diff --git a/doc/usage/fit/howto.rst b/doc/usage/fit/howto.rst
new file mode 100644
index 00000000000..c933703d1d0
--- /dev/null
+++ b/doc/usage/fit/howto.rst
@@ -0,0 +1,419 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+How to use images in the new image format
+=========================================
+
+Overview
+--------
+
+The new uImage format allows more flexibility in handling images of various
+types (kernel, ramdisk, etc.), it also enhances integrity protection of images
+with sha1 and md5 checksums.
+
+Two auxiliary tools are needed on the development host system in order to
+create an uImage in the new format: mkimage and dtc, although only one
+(mkimage) is invoked directly. dtc is called from within mkimage and operates
+behind the scenes, but needs to be present in the $PATH nevertheless. It is
+important that the dtc used has support for binary includes -- refer to::
+
+    git://git.kernel.org/pub/scm/utils/dtc/dtc.git
+
+for its latest version. mkimage (together with dtc) takes as input
+an image source file, which describes the contents of the image and defines
+its various properties used during booting. By convention, image source file
+has the ".its" extension, also, the details of its format are given in
+doc/uImage.FIT/source_file_format.txt. The actual data that is to be included in
+the uImage (kernel, ramdisk, etc.) is specified in the image source file in the
+form of paths to appropriate data files. The outcome of the image creation
+process is a binary file (by convention with the ".itb" extension) that
+contains all the referenced data (kernel, ramdisk, etc.) and other information
+needed by U-Boot to handle the uImage properly. The uImage file is then
+transferred to the target (e.g., via tftp) and booted using the bootm command.
+
+To summarize the prerequisites needed for new uImage creation:
+
+- mkimage
+- dtc (with support for binary includes)
+- image source file (`*.its`)
+- image data file(s)
+
+
+Here's a graphical overview of the image creation and booting process::
+
+    image source file     mkimage + dtc          transfer to target
+        +          ---------------> image file --------------------> bootm
+    image data file(s)
+
+SPL usage
+---------
+
+The SPL can make use of the new image format as well, this traditionally
+is used to ship multiple device tree files within one image. Code in the SPL
+will choose the one matching the current board and append this to the
+U-Boot proper binary to be automatically used up by it.
+Aside from U-Boot proper and one device tree blob the SPL can load multiple,
+arbitrary image files as well. These binaries should be specified in their
+own subnode under the /images node, which should then be referenced from one or
+multiple /configurations subnodes. The required images must be enumerated in
+the "loadables" property as a list of strings.
+
+If a platform specific image source file (.its) is shipped with the U-Boot
+source, it can be specified using the CONFIG_SPL_FIT_SOURCE Kconfig symbol.
+In this case it will be automatically used by U-Boot's Makefile to generate
+the image.
+If a static source file is not flexible enough, CONFIG_SPL_FIT_GENERATOR
+can point to a script which generates this image source file during
+the build process. It gets passed a list of device tree files (taken from the
+CONFIG_OF_LIST symbol).
+
+The SPL also records to a DT all additional images (called loadables) which are
+loaded. The information about loadables locations is passed via the DT node with
+fit-images name.
+
+Finally, if there are multiple xPL phases (e.g. SPL, VPL), images can be marked
+as intended for a particular phase using the 'phase' property. For example, if
+fit_image_load() is called with image_ph(IH_PHASE_SPL, IH_TYPE_FIRMWARE), then
+only the image listed into the "firmware" property where phase is set to "spl"
+will be loaded.
+
+Loadables Example
+-----------------
+Consider the following case for an ARM64 platform where U-Boot runs in EL2
+started by ATF where SPL is loading U-Boot (as loadables) and ATF (as firmware).
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "Configuration to load ATF before U-Boot";
+
+        images {
+            uboot {
+                description = "U-Boot (64-bit)";
+                data = /incbin/("u-boot-nodtb.bin");
+                type = "firmware";
+                os = "u-boot";
+                arch = "arm64";
+                compression = "none";
+                load = <0x8 0x8000000>;
+                entry = <0x8 0x8000000>;
+                hash {
+                    algo = "md5";
+                };
+            };
+            atf {
+                description = "ARM Trusted Firmware";
+                data = /incbin/("bl31.bin");
+                type = "firmware";
+                os = "arm-trusted-firmware";
+                arch = "arm64";
+                compression = "none";
+                load = <0xfffea000>;
+                entry = <0xfffea000>;
+                hash {
+                    algo = "md5";
+                };
+            };
+            fdt_1 {
+                description = "zynqmp-zcu102-revA";
+                data = /incbin/("arch/arm/dts/zynqmp-zcu102-revA.dtb");
+                type = "flat_dt";
+                arch = "arm64";
+                compression = "none";
+                load = <0x100000>;
+                hash {
+                    algo = "md5";
+                };
+            };
+        };
+        configurations {
+            default = "config_1";
+
+            config_1 {
+                description = "zynqmp-zcu102-revA";
+                firmware = "atf";
+                loadables = "uboot";
+                fdt = "fdt_1";
+            };
+        };
+    };
+
+In this case the SPL records via fit-images DT node the information about
+loadables U-Boot image::
+
+    ZynqMP> fdt addr $fdtcontroladdr
+    ZynqMP> fdt print /fit-images
+    fit-images {
+        uboot {
+            os = "u-boot";
+            type = "firmware";
+            size = <0x001017c8>;
+            entry = <0x00000008 0x08000000>;
+            load = <0x00000008 0x08000000>;
+        };
+    };
+
+As you can see entry and load properties are 64bit wide to support loading
+images above 4GB (in past entry and load properties where just 32bit).
+
+
+Example 1 -- old-style (non-FDT) kernel booting
+-----------------------------------------------
+
+Consider a simple scenario, where a PPC Linux kernel built from sources on the
+development host is to be booted old-style (non-FDT) by U-Boot on an embedded
+target. Assume that the outcome of the build is vmlinux.bin.gz, a file which
+contains a gzip-compressed PPC Linux kernel (the only data file in this case).
+The uImage can be produced using the image source file
+doc/uImage.FIT/kernel.its (note that kernel.its assumes that vmlinux.bin.gz is
+in the current working directory; if desired, an alternative path can be
+specified in the kernel.its file). Here's how to create the image and inspect
+its contents:
+
+[on the host system]::
+
+    $ mkimage -f kernel.its kernel.itb
+    DTC: dts->dtb  on file "kernel.its"
+    $
+    $ mkimage -l kernel.itb
+    FIT description: Simple image with single Linux kernel
+    Created:     Tue Mar 11 17:26:15 2008
+     Image 0 (kernel)
+      Description:    Vanilla Linux kernel
+      Type:        Kernel Image
+      Compression:    gzip compressed
+      Data Size:    943347 Bytes = 921.24 kB = 0.90 MB
+      Architecture: PowerPC
+      OS:        Linux
+      Load Address: 0x00000000
+      Entry Point:    0x00000000
+      Hash algo:    crc32
+      Hash value:    2ae2bb40
+      Hash algo:    sha1
+      Hash value:    3c200f34e2c226ddc789240cca0c59fc54a67cf4
+     Default Configuration: 'config-1'
+     Configuration 0 (config-1)
+      Description:    Boot Linux kernel
+      Kernel:    kernel
+
+
+The resulting image file kernel.itb can be now transferred to the target,
+inspected and booted (note that first three U-Boot commands below are shown
+for completeness -- they are part of the standard booting procedure and not
+specific to the new image format).
+
+[on the target system]::
+
+    => print nfsargs
+    nfsargs=setenv bootargs root=/dev/nfs rw nfsroot=${serverip}:${rootpath}
+    => print addip
+    addip=setenv bootargs ${bootargs} ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}:${netdev}:off panic=1
+    => run nfsargs addip
+    => tftp 900000 /path/to/tftp/location/kernel.itb
+    Using FEC device
+    TFTP from server 192.168.1.1; our IP address is 192.168.160.5
+    Filename '/path/to/tftp/location/kernel.itb'.
+    Load address: 0x900000
+    Loading: #################################################################
+    done
+    Bytes transferred = 944464 (e6950 hex)
+    => iminfo
+
+    ## Checking Image at 00900000 ...
+       FIT image found
+       FIT description: Simple image with single Linux kernel
+       Created:        2008-03-11    16:26:15 UTC
+        Image 0 (kernel)
+         Description:  Vanilla Linux kernel
+         Type:       Kernel Image
+         Compression:  gzip compressed
+         Data Start:   0x009000e0
+         Data Size:    943347 Bytes = 921.2 kB
+         Architecture: PowerPC
+         OS:       Linux
+         Load Address: 0x00000000
+         Entry Point:  0x00000000
+         Hash algo:    crc32
+         Hash value:   2ae2bb40
+         Hash algo:    sha1
+         Hash value:   3c200f34e2c226ddc789240cca0c59fc54a67cf4
+        Default Configuration: 'config-1'
+        Configuration 0 (config-1)
+         Description:  Boot Linux kernel
+         Kernel:       kernel
+
+    => bootm
+    ## Booting kernel from FIT Image at 00900000 ...
+       Using 'config-1' configuration
+       Trying 'kernel' kernel subimage
+         Description:  Vanilla Linux kernel
+         Type:       Kernel Image
+         Compression:  gzip compressed
+         Data Start:   0x009000e0
+         Data Size:    943347 Bytes = 921.2 kB
+         Architecture: PowerPC
+         OS:       Linux
+         Load Address: 0x00000000
+         Entry Point:  0x00000000
+         Hash algo:    crc32
+         Hash value:   2ae2bb40
+         Hash algo:    sha1
+         Hash value:   3c200f34e2c226ddc789240cca0c59fc54a67cf4
+       Verifying Hash Integrity ... crc32+ sha1+ OK
+       Uncompressing Kernel Image ... OK
+    Memory BAT mapping: BAT2=256Mb, BAT3=0Mb, residual: 0Mb
+    Linux version 2.4.25 (m8@hekate) (gcc version 4.0.0 (DENX ELDK 4.0 4.0.0)) #2 czw lip 5 17:56:18 CEST 2007
+    On node 0 totalpages: 65536
+    zone(0): 65536 pages.
+    zone(1): 0 pages.
+    zone(2): 0 pages.
+    Kernel command line: root=/dev/nfs rw nfsroot=192.168.1.1:/opt/eldk-4.1/ppc_6xx ip=192.168.160.5:192.168.1.1::255.255.0.0:lite5200b:eth0:off panic=1
+    Calibrating delay loop... 307.20 BogoMIPS
+
+
+Example 2 -- new-style (FDT) kernel booting
+-------------------------------------------
+
+Consider another simple scenario, where a PPC Linux kernel is to be booted
+new-style, i.e., with a FDT blob. In this case there are two prerequisite data
+files: vmlinux.bin.gz (Linux kernel) and target.dtb (FDT blob). The uImage can
+be produced using image source file doc/uImage.FIT/kernel_fdt.its like this
+(note again, that both prerequisite data files are assumed to be present in
+the current working directory -- image source file kernel_fdt.its can be
+modified to take the files from some other location if needed):
+
+[on the host system]::
+
+    $ mkimage -f kernel_fdt.its kernel_fdt.itb
+    DTC: dts->dtb  on file "kernel_fdt.its"
+    $
+    $ mkimage -l kernel_fdt.itb
+    FIT description: Simple image with single Linux kernel and FDT blob
+    Created:     Tue Mar 11 16:29:22 2008
+     Image 0 (kernel)
+      Description:    Vanilla Linux kernel
+      Type:        Kernel Image
+      Compression:    gzip compressed
+      Data Size:    1092037 Bytes = 1066.44 kB = 1.04 MB
+      Architecture: PowerPC
+      OS:        Linux
+      Load Address: 0x00000000
+      Entry Point:    0x00000000
+      Hash algo:    crc32
+      Hash value:    2c0cc807
+      Hash algo:    sha1
+      Hash value:    264b59935470e42c418744f83935d44cdf59a3bb
+     Image 1 (fdt-1)
+      Description:    Flattened Device Tree blob
+      Type:        Flat Device Tree
+      Compression:    uncompressed
+      Data Size:    16384 Bytes = 16.00 kB = 0.02 MB
+      Architecture: PowerPC
+      Hash algo:    crc32
+      Hash value:    0d655d71
+      Hash algo:    sha1
+      Hash value:    25ab4e15cd4b8a5144610394560d9c318ce52def
+     Default Configuration: 'conf-1'
+     Configuration 0 (conf-1)
+      Description:    Boot Linux kernel with FDT blob
+      Kernel:    kernel
+      FDT:        fdt-1
+
+
+The resulting image file kernel_fdt.itb can be now transferred to the target,
+inspected and booted:
+
+[on the target system]::
+
+    => tftp 900000 /path/to/tftp/location/kernel_fdt.itb
+    Using FEC device
+    TFTP from server 192.168.1.1; our IP address is 192.168.160.5
+    Filename '/path/to/tftp/location/kernel_fdt.itb'.
+    Load address: 0x900000
+    Loading: #################################################################
+         ###########
+    done
+    Bytes transferred = 1109776 (10ef10 hex)
+    => iminfo
+
+    ## Checking Image at 00900000 ...
+       FIT image found
+       FIT description: Simple image with single Linux kernel and FDT blob
+       Created:        2008-03-11    15:29:22 UTC
+        Image 0 (kernel)
+         Description:  Vanilla Linux kernel
+         Type:       Kernel Image
+         Compression:  gzip compressed
+         Data Start:   0x009000ec
+         Data Size:    1092037 Bytes =  1 MB
+         Architecture: PowerPC
+         OS:       Linux
+         Load Address: 0x00000000
+         Entry Point:  0x00000000
+         Hash algo:    crc32
+         Hash value:   2c0cc807
+         Hash algo:    sha1
+         Hash value:   264b59935470e42c418744f83935d44cdf59a3bb
+        Image 1 (fdt-1)
+         Description:  Flattened Device Tree blob
+         Type:       Flat Device Tree
+         Compression:  uncompressed
+         Data Start:   0x00a0abdc
+         Data Size:    16384 Bytes = 16 kB
+         Architecture: PowerPC
+         Hash algo:    crc32
+         Hash value:   0d655d71
+         Hash algo:    sha1
+         Hash value:   25ab4e15cd4b8a5144610394560d9c318ce52def
+        Default Configuration: 'conf-1'
+        Configuration 0 (conf-1)
+         Description:  Boot Linux kernel with FDT blob
+         Kernel:       kernel
+         FDT:       fdt-1
+    => bootm
+    ## Booting kernel from FIT Image at 00900000 ...
+       Using 'conf-1' configuration
+       Trying 'kernel' kernel subimage
+         Description:  Vanilla Linux kernel
+         Type:       Kernel Image
+         Compression:  gzip compressed
+         Data Start:   0x009000ec
+         Data Size:    1092037 Bytes =  1 MB
+         Architecture: PowerPC
+         OS:       Linux
+         Load Address: 0x00000000
+         Entry Point:  0x00000000
+         Hash algo:    crc32
+         Hash value:   2c0cc807
+         Hash algo:    sha1
+         Hash value:   264b59935470e42c418744f83935d44cdf59a3bb
+       Verifying Hash Integrity ... crc32+ sha1+ OK
+       Uncompressing Kernel Image ... OK
+    ## Flattened Device Tree from FIT Image at 00900000
+       Using 'conf-1' configuration
+       Trying 'fdt-1' FDT blob subimage
+         Description:  Flattened Device Tree blob
+         Type:       Flat Device Tree
+         Compression:  uncompressed
+         Data Start:   0x00a0abdc
+         Data Size:    16384 Bytes = 16 kB
+         Architecture: PowerPC
+         Hash algo:    crc32
+         Hash value:   0d655d71
+         Hash algo:    sha1
+         Hash value:   25ab4e15cd4b8a5144610394560d9c318ce52def
+       Verifying Hash Integrity ... crc32+ sha1+ OK
+       Booting using the fdt blob at 0xa0abdc
+       Loading Device Tree to 007fc000, end 007fffff ... OK
+    [    0.000000] Using lite5200 machine description
+    [    0.000000] Linux version 2.6.24-rc6-gaebecdfc (m8@hekate) (gcc version 4.0.0 (DENX ELDK 4.1 4.0.0)) #1 Sat Jan 12 15:38:48 CET 2008
+
+
+Example 3 -- advanced booting
+-----------------------------
+
+Refer to :doc:`multi` for an image source file that allows more
+sophisticated booting scenarios (multiple kernels, ramdisks and fdt blobs).
+
+.. sectionauthor:: Bartlomiej Sieka <[email protected]>
diff --git a/doc/usage/fit.rst b/doc/usage/fit/index.rst
index 70374340577..bd25bd30b28 100644
--- a/doc/usage/fit.rst
+++ b/doc/usage/fit/index.rst
@@ -6,3 +6,14 @@ Flat Image Tree (FIT)
 U-Boot uses Flat Image Tree (FIT) as a standard file format for packaging
 images that it it reads and boots. Documentation about FIT is available at
 doc/uImage.FIT
+
+.. toctree::
+    :maxdepth: 1
+
+    source_file_format
+    howto
+    x86-fit-boot
+    signature
+    verified-boot
+    beaglebone_vboot
+    overlay-fdt-boot
diff --git a/doc/usage/fit/kernel.rst b/doc/usage/fit/kernel.rst
new file mode 100644
index 00000000000..012a81efead
--- /dev/null
+++ b/doc/usage/fit/kernel.rst
@@ -0,0 +1,93 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Single kernel
+=============
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "Simple image with single Linux kernel";
+        #address-cells = <1>;
+
+        images {
+            kernel {
+                description = "Vanilla Linux kernel";
+                data = /incbin/("./vmlinux.bin.gz");
+                type = "kernel";
+                arch = "ppc";
+                os = "linux";
+                compression = "gzip";
+                load = <00000000>;
+                entry = <00000000>;
+                hash-1 {
+                    algo = "crc32";
+                };
+                hash-2 {
+                    algo = "sha1";
+                };
+            };
+        };
+
+        configurations {
+            default = "config-1";
+            config-1 {
+                description = "Boot Linux kernel";
+                kernel = "kernel";
+            };
+        };
+    };
+
+
+For x86 a setup node is also required: see x86-fit-boot::
+
+    /dts-v1/;
+
+    / {
+        description = "Simple image with single Linux kernel on x86";
+        #address-cells = <1>;
+
+        images {
+            kernel {
+                description = "Vanilla Linux kernel";
+                data = /incbin/("./image.bin.lzo");
+                type = "kernel";
+                arch = "x86";
+                os = "linux";
+                compression = "lzo";
+                load = <0x01000000>;
+                entry = <0x00000000>;
+                hash-2 {
+                    algo = "sha1";
+                };
+            };
+
+            setup {
+                description = "Linux setup.bin";
+                data = /incbin/("./setup.bin");
+                type = "x86_setup";
+                arch = "x86";
+                os = "linux";
+                compression = "none";
+                load = <0x00090000>;
+                entry = <0x00090000>;
+                hash-2 {
+                    algo = "sha1";
+                };
+            };
+        };
+
+        configurations {
+            default = "config-1";
+            config-1 {
+                description = "Boot Linux kernel";
+                kernel = "kernel";
+                setup = "setup";
+            };
+        };
+    };
+
+Note: the above assumes a 32-bit kernel. To directly boot a 64-bit kernel,
+change both arch values to "x86_64". U-Boot will then change to 64-bit mode
+before booting the kernel (see boot_linux_kernel()).
diff --git a/doc/usage/fit/kernel_fdt.rst b/doc/usage/fit/kernel_fdt.rst
new file mode 100644
index 00000000000..8eee13af780
--- /dev/null
+++ b/doc/usage/fit/kernel_fdt.rst
@@ -0,0 +1,54 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Single kernel and FDT blob
+==========================
+
+::
+
+	/dts-v1/;
+
+	/ {
+	description = "Simple image with single Linux kernel and FDT blob";
+	#address-cells = <1>;
+
+	images {
+		kernel {
+		description = "Vanilla Linux kernel";
+		data = /incbin/("./vmlinux.bin.gz");
+		type = "kernel";
+		arch = "ppc";
+		os = "linux";
+		compression = "gzip";
+		load = <00000000>;
+		entry = <00000000>;
+		hash-1 {
+			algo = "crc32";
+		};
+		hash-2 {
+			algo = "sha1";
+		};
+		};
+		fdt-1 {
+		description = "Flattened Device Tree blob";
+		data = /incbin/("./target.dtb");
+		type = "flat_dt";
+		arch = "ppc";
+		compression = "none";
+		hash-1 {
+			algo = "crc32";
+		};
+		hash-2 {
+			algo = "sha1";
+		};
+		};
+	};
+
+	configurations {
+		default = "conf-1";
+		conf-1 {
+		description = "Boot Linux kernel with FDT blob";
+		kernel = "kernel";
+		fdt = "fdt-1";
+		};
+	};
+	};
diff --git a/doc/usage/fit/kernel_fdts_compressed.rst b/doc/usage/fit/kernel_fdts_compressed.rst
new file mode 100644
index 00000000000..0b169c7c27c
--- /dev/null
+++ b/doc/usage/fit/kernel_fdts_compressed.rst
@@ -0,0 +1,77 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Kernel and multiple compressed FDT blobs
+========================================
+
+Since the FDTs are compressed, configurations must provide a compatible
+string to match directly.
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "Image with single Linux kernel and compressed FDT blobs";
+        #address-cells = <1>;
+
+        images {
+            kernel {
+                description = "Vanilla Linux kernel";
+                data = /incbin/("./vmlinux.bin.gz");
+                type = "kernel";
+                arch = "ppc";
+                os = "linux";
+                compression = "gzip";
+                load = <00000000>;
+                entry = <00000000>;
+                hash-1 {
+                    algo = "crc32";
+                };
+                hash-2 {
+                    algo = "sha1";
+                };
+            };
+            fdt@1 {
+                description = "Flattened Device Tree blob 1";
+                data = /incbin/("./myboard-var1.dtb");
+                type = "flat_dt";
+                arch = "ppc";
+                compression = "gzip";
+                hash-1 {
+                    algo = "crc32";
+                };
+                hash-2 {
+                    algo = "sha1";
+                };
+            };
+            fdt@2 {
+                description = "Flattened Device Tree blob 2";
+                data = /incbin/("./myboard-var2.dtb");
+                type = "flat_dt";
+                arch = "ppc";
+                compression = "lzma";
+                hash-1 {
+                    algo = "crc32";
+                };
+                hash-2 {
+                    algo = "sha1";
+                };
+            };
+        };
+
+        configurations {
+            default = "conf@1";
+            conf@1 {
+                description = "Boot Linux kernel with FDT blob 1";
+                kernel = "kernel";
+                fdt = "fdt@1";
+                compatible = "myvendor,myboard-variant1";
+            };
+            conf@2 {
+                description = "Boot Linux kernel with FDT blob 2";
+                kernel = "kernel";
+                fdt = "fdt@2";
+                compatible = "myvendor,myboard-variant2";
+            };
+        };
+    };
diff --git a/doc/usage/fit/multi-with-fpga.rst b/doc/usage/fit/multi-with-fpga.rst
new file mode 100644
index 00000000000..28d7d5d2626
--- /dev/null
+++ b/doc/usage/fit/multi-with-fpga.rst
@@ -0,0 +1,70 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Multiple kernels, ramdisks and FDT blobs with FPGA
+==================================================
+
+This example makes use of the 'loadables' field::
+
+    /dts-v1/;
+
+    / {
+        description = "Configuration to load fpga before Kernel";
+        #address-cells = <1>;
+
+        images {
+            fdt-1 {
+                description = "zc706";
+                data = /incbin/("/tftpboot/devicetree.dtb");
+                type = "flat_dt";
+                arch = "arm";
+                compression = "none";
+                load = <0x10000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            fpga {
+                description = "FPGA";
+                data = /incbin/("/tftpboot/download.bit");
+                type = "fpga";
+                arch = "arm";
+                compression = "none";
+                load = <0x30000000>;
+                compatible = "u-boot,fpga-legacy"
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            linux_kernel {
+                description = "Linux";
+                data = /incbin/("/tftpboot/zImage");
+                type = "kernel";
+                arch = "arm";
+                os = "linux";
+                compression = "none";
+                load = <0x8000>;
+                entry = <0x8000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+        };
+
+        configurations {
+            default = "config-2";
+            config-1 {
+                description = "Linux";
+                kernel = "linux_kernel";
+                fdt = "fdt-1";
+            };
+
+            config-2 {
+                description = "Linux with fpga";
+                kernel = "linux_kernel";
+                fdt = "fdt-1";
+                loadables = "fpga";
+            };
+        };
+    };
diff --git a/doc/usage/fit/multi-with-loadables.rst b/doc/usage/fit/multi-with-loadables.rst
new file mode 100644
index 00000000000..a0241df96ca
--- /dev/null
+++ b/doc/usage/fit/multi-with-loadables.rst
@@ -0,0 +1,91 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Multiple kernels, ramdisks and FDT blobs with Xen
+=================================================
+
+This example makes use of the 'loadables' field::
+
+    /dts-v1/;
+
+    / {
+        description = "Configuration to load a Xen Kernel";
+        #address-cells = <1>;
+
+        images {
+            xen_kernel {
+                description = "xen binary";
+                data = /incbin/("./xen");
+                type = "kernel";
+                arch = "arm";
+                os = "linux";
+                compression = "none";
+                load = <0xa0000000>;
+                entry = <0xa0000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            fdt-1 {
+                description = "xexpress-ca15 tree blob";
+                data = /incbin/("./vexpress-v2p-ca15-tc1.dtb");
+                type = "flat_dt";
+                arch = "arm";
+                compression = "none";
+                load = <0xb0000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            fdt-2 {
+                description = "xexpress-ca15 tree blob";
+                data = /incbin/("./vexpress-v2p-ca15-tc1.dtb");
+                type = "flat_dt";
+                arch = "arm";
+                compression = "none";
+                load = <0xb0400000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            linux_kernel {
+                description = "Linux Image";
+                data = /incbin/("./Image");
+                type = "kernel";
+                arch = "arm";
+                os = "linux";
+                compression = "none";
+                load = <0xa0000000>;
+                entry = <0xa0000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+        };
+
+        configurations {
+            default = "config-2";
+
+            config-1 {
+                description = "Just plain Linux";
+                kernel = "linux_kernel";
+                fdt = "fdt-1";
+            };
+
+            config-2 {
+                description = "Xen one loadable";
+                kernel = "xen_kernel";
+                fdt = "fdt-1";
+                loadables = "linux_kernel";
+            };
+
+            config-3 {
+                description = "Xen two loadables";
+                kernel = "xen_kernel";
+                fdt = "fdt-1";
+                loadables = "linux_kernel", "fdt-2";
+            };
+        };
+    };
diff --git a/doc/usage/fit/multi.rst b/doc/usage/fit/multi.rst
new file mode 100644
index 00000000000..2e6ae58c409
--- /dev/null
+++ b/doc/usage/fit/multi.rst
@@ -0,0 +1,136 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Multiple kernels, ramdisks and FDT blobs
+========================================
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "Various kernels, ramdisks and FDT blobs";
+        #address-cells = <1>;
+
+        images {
+            kernel-1 {
+                description = "vanilla-2.6.23";
+                data = /incbin/("./vmlinux.bin.gz");
+                type = "kernel";
+                arch = "ppc";
+                os = "linux";
+                compression = "gzip";
+                load = <00000000>;
+                entry = <00000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+                hash-2 {
+                    algo = "sha1";
+                };
+            };
+
+            kernel-2 {
+                description = "2.6.23-denx";
+                data = /incbin/("./2.6.23-denx.bin.gz");
+                type = "kernel";
+                arch = "ppc";
+                os = "linux";
+                compression = "gzip";
+                load = <00000000>;
+                entry = <00000000>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+
+            kernel-3 {
+                description = "2.4.25-denx";
+                data = /incbin/("./2.4.25-denx.bin.gz");
+                type = "kernel";
+                arch = "ppc";
+                os = "linux";
+                compression = "gzip";
+                load = <00000000>;
+                entry = <00000000>;
+                hash-1 {
+                    algo = "md5";
+                };
+            };
+
+            ramdisk-1 {
+                description = "eldk-4.2-ramdisk";
+                data = /incbin/("./eldk-4.2-ramdisk");
+                type = "ramdisk";
+                arch = "ppc";
+                os = "linux";
+                compression = "gzip";
+                load = <00000000>;
+                entry = <00000000>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+
+            ramdisk-2 {
+                description = "eldk-3.1-ramdisk";
+                data = /incbin/("./eldk-3.1-ramdisk");
+                type = "ramdisk";
+                arch = "ppc";
+                os = "linux";
+                compression = "gzip";
+                load = <00000000>;
+                entry = <00000000>;
+                hash-1 {
+                    algo = "crc32";
+                };
+            };
+
+            fdt-1 {
+                description = "tqm5200-fdt";
+                data = /incbin/("./tqm5200.dtb");
+                type = "flat_dt";
+                arch = "ppc";
+                compression = "none";
+                hash-1 {
+                    algo = "crc32";
+                };
+            };
+
+            fdt-2 {
+                description = "tqm5200s-fdt";
+                data = /incbin/("./tqm5200s.dtb");
+                type = "flat_dt";
+                arch = "ppc";
+                compression = "none";
+                load = <00700000>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+
+        };
+
+        configurations {
+            default = "config-1";
+
+            config-1 {
+                description = "tqm5200 vanilla-2.6.23 configuration";
+                kernel = "kernel-1";
+                ramdisk = "ramdisk-1";
+                fdt = "fdt-1";
+            };
+
+            config-2 {
+                description = "tqm5200s denx-2.6.23 configuration";
+                kernel = "kernel-2";
+                ramdisk = "ramdisk-1";
+                fdt = "fdt-2";
+            };
+
+            config-3 {
+                description = "tqm5200s denx-2.4.25 configuration";
+                kernel = "kernel-3";
+                ramdisk = "ramdisk-2";
+            };
+        };
+    };
diff --git a/doc/usage/fit/multi_spl.rst b/doc/usage/fit/multi_spl.rst
new file mode 100644
index 00000000000..74b6f865abd
--- /dev/null
+++ b/doc/usage/fit/multi_spl.rst
@@ -0,0 +1,101 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Multiple images for SPL
+=======================
+
+(Bogus) example FIT image description file demonstrating the usage
+of multiple images loaded by the SPL.
+Several binaries will be loaded at their respective load addresses.
+
+For booting U-Boot, "firmware" is searched first. If not found, "loadables"
+is used to identify images to be loaded into memory. If falcon boot is
+enabled, "kernel" is searched first. If not found, it falls back to the
+same flow as booting U-Boot. Changing image type will result skipping
+specific image.
+
+Finally the one image specifying an entry point will be entered by the SPL.
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "multiple firmware blobs and U-Boot, loaded by SPL";
+        #address-cells = <0x1>;
+
+        images {
+
+            uboot {
+                description = "U-Boot (64-bit)";
+                type = "standalone";
+                arch = "arm64";
+                compression = "none";
+                load = <0x4a000000>;
+            };
+
+            atf {
+                description = "ARM Trusted Firmware";
+                type = "firmware";
+                arch = "arm64";
+                compression = "none";
+                load = <0x18000>;
+                entry = <0x18000>;
+            };
+
+            mgmt-firmware {
+                description = "arisc management processor firmware";
+                type = "firmware";
+                arch = "or1k";
+                compression = "none";
+                load = <0x40000>;
+            };
+
+            fdt-1 {
+                description = "Pine64+ DT";
+                type = "flat_dt";
+                compression = "none";
+                load = <0x4fa00000>;
+                arch = "arm64";
+            };
+
+            fdt-2 {
+                description = "Pine64 DT";
+                type = "flat_dt";
+                compression = "none";
+                load = <0x4fa00000>;
+                arch = "arm64";
+            };
+
+            kernel {
+                description = "4.7-rc5 kernel";
+                type = "kernel";
+                compression = "none";
+                load = <0x40080000>;
+                arch = "arm64";
+            };
+
+            initrd {
+                description = "Debian installer initrd";
+                type = "ramdisk";
+                compression = "none";
+                load = <0x4fe00000>;
+                arch = "arm64";
+            };
+        };
+
+        configurations {
+            default = "config-1";
+
+            config-1 {
+                description = "sun50i-a64-pine64-plus";
+                loadables = "uboot", "atf", "kernel", "initrd";
+                fdt = "fdt-1";
+            };
+
+            config-2 {
+                description = "sun50i-a64-pine64";
+                loadables = "uboot", "atf", "mgmt-firmware";
+                fdt = "fdt-2";
+            };
+        };
+    };
diff --git a/doc/usage/fit/overlay-fdt-boot.rst b/doc/usage/fit/overlay-fdt-boot.rst
new file mode 100644
index 00000000000..a7db1a37f7a
--- /dev/null
+++ b/doc/usage/fit/overlay-fdt-boot.rst
@@ -0,0 +1,227 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+U-Boot FDT Overlay FIT usage
+============================
+
+Introduction
+------------
+
+In many cases it is desirable to have a single FIT image support a multitude
+of similar boards and their expansion options. The same kernel on DT enabled
+platforms can support this easily enough by providing a DT blob upon boot
+that matches the desired configuration.
+
+This document focuses on specifically using overlays as part of a FIT image.
+General information regarding overlays including its syntax and building it
+can be found in doc/README.fdt-overlays
+
+Configuration without overlays
+------------------------------
+
+Take a hypothetical board named 'foo' where there are different supported
+revisions, reva and revb. Assume that both board revisions can use add a bar
+add-on board, while only the revb board can use a baz add-on board.
+
+Without using overlays the configuration would be as follows for every case::
+
+	/dts-v1/;
+	/ {
+	    images {
+	    kernel {
+		data = /incbin/("./zImage");
+		type = "kernel";
+		arch = "arm";
+		os = "linux";
+		load = <0x82000000>;
+		entry = <0x82000000>;
+	    };
+	    fdt-1 {
+		data = /incbin/("./foo-reva.dtb");
+		type = "flat_dt";
+		arch = "arm";
+	    };
+	    fdt-2 {
+		data = /incbin/("./foo-revb.dtb");
+		type = "flat_dt";
+		arch = "arm";
+	    };
+	    fdt-3 {
+		data = /incbin/("./foo-reva-bar.dtb");
+		type = "flat_dt";
+		arch = "arm";
+	    };
+	    fdt-4 {
+		data = /incbin/("./foo-revb-bar.dtb");
+		type = "flat_dt";
+		arch = "arm";
+	    };
+	    fdt-5 {
+		data = /incbin/("./foo-revb-baz.dtb");
+		type = "flat_dt";
+		arch = "arm";
+	    };
+	    fdt-6 {
+		data = /incbin/("./foo-revb-bar-baz.dtb");
+		type = "flat_dt";
+		arch = "arm";
+	    };
+	    };
+
+	    configurations {
+	    default = "foo-reva.dtb;
+	    foo-reva.dtb {
+		kernel = "kernel";
+		fdt = "fdt-1";
+	    };
+	    foo-revb.dtb {
+		kernel = "kernel";
+		fdt = "fdt-2";
+	    };
+	    foo-reva-bar.dtb {
+		kernel = "kernel";
+		fdt = "fdt-3";
+	    };
+	    foo-revb-bar.dtb {
+		kernel = "kernel";
+		fdt = "fdt-4";
+	    };
+	    foo-revb-baz.dtb {
+		kernel = "kernel";
+		fdt = "fdt-5";
+	    };
+	    foo-revb-bar-baz.dtb {
+		kernel = "kernel";
+		fdt = "fdt-6";
+	    };
+	    };
+	};
+
+Note the blob needs to be compiled for each case and the combinatorial explosion of
+configurations. A typical device tree blob is in the low hunderds of kbytes so a
+multitude of configuration grows the image quite a bit.
+
+Booting this image is done by using::
+
+    # bootm <addr>#<config>
+
+Where config is one of::
+
+    foo-reva.dtb, foo-revb.dtb, foo-reva-bar.dtb, foo-revb-bar.dtb,
+    foo-revb-baz.dtb, foo-revb-bar-baz.dtb
+
+This selects the DTB to use when booting.
+
+Configuration using overlays
+----------------------------
+
+Device tree overlays can be applied to a base DT and result in the same blob
+being passed to the booting kernel. This saves on space and avoid the combinatorial
+explosion problem::
+
+    /dts-v1/;
+    / {
+        images {
+            kernel {
+                data = /incbin/("./zImage");
+                type = "kernel";
+                arch = "arm";
+                os = "linux";
+                load = <0x82000000>;
+                entry = <0x82000000>;
+            };
+            fdt-1 {
+                data = /incbin/("./foo.dtb");
+                type = "flat_dt";
+                arch = "arm";
+                load = <0x87f00000>;
+            };
+            fdt-2 {
+                data = /incbin/("./reva.dtbo");
+                type = "flat_dt";
+                arch = "arm";
+                load = <0x87fc0000>;
+            };
+            fdt-3 {
+                data = /incbin/("./revb.dtbo");
+                type = "flat_dt";
+                arch = "arm";
+                load = <0x87fc0000>;
+            };
+            fdt-4 {
+                data = /incbin/("./bar.dtbo");
+                type = "flat_dt";
+                arch = "arm";
+                load = <0x87fc0000>;
+            };
+            fdt-5 {
+                data = /incbin/("./baz.dtbo");
+                type = "flat_dt";
+                arch = "arm";
+                load = <0x87fc0000>;
+            };
+        };
+
+        configurations {
+            default = "foo-reva.dtb;
+            foo-reva.dtb {
+                kernel = "kernel";
+                fdt = "fdt-1", "fdt-2";
+            };
+            foo-revb.dtb {
+                kernel = "kernel";
+                fdt = "fdt-1", "fdt-3";
+            };
+            foo-reva-bar.dtb {
+                kernel = "kernel";
+                fdt = "fdt-1", "fdt-2", "fdt-4";
+            };
+            foo-revb-bar.dtb {
+                kernel = "kernel";
+                fdt = "fdt-1", "fdt-3", "fdt-4";
+            };
+            foo-revb-baz.dtb {
+                kernel = "kernel";
+                fdt = "fdt-1", "fdt-3", "fdt-5";
+            };
+            foo-revb-bar-baz.dtb {
+                kernel = "kernel";
+                fdt = "fdt-1", "fdt-3", "fdt-4", "fdt-5";
+            };
+            bar {
+                fdt = "fdt-4";
+            };
+            baz {
+                fdt = "fdt-5";
+            };
+        };
+    };
+
+Booting this image is exactly the same as the non-overlay example.
+u-boot will retrieve the base blob and apply the overlays in sequence as
+they are declared in the configuration.
+
+Note the minimum amount of different DT blobs, as well as the requirement for
+the DT blobs to have a load address; the overlay application requires the blobs
+to be writeable.
+
+Configuration using overlays and feature selection
+--------------------------------------------------
+
+Although the configuration in the previous section works is a bit inflexible
+since it requires all possible configuration options to be laid out before
+hand in the FIT image. For the add-on boards the extra config selection method
+might make sense.
+
+Note the two bar & baz configuration nodes. To boot a reva board with
+the bar add-on board enabled simply use::
+
+    => bootm <addr>#foo-reva.dtb#bar
+
+While booting a revb with bar and baz is as follows::
+
+    => bootm <addr>#foo-revb.dtb#bar#baz
+
+The limitation for a feature selection configuration node is that a single
+fdt option is currently supported.
+
+.. sectionauthor:: Pantelis Antoniou <[email protected]>, 12/6/2017
diff --git a/doc/usage/fit/sec_firmware_ppa.rst b/doc/usage/fit/sec_firmware_ppa.rst
new file mode 100644
index 00000000000..4cb292cb4ee
--- /dev/null
+++ b/doc/usage/fit/sec_firmware_ppa.rst
@@ -0,0 +1,54 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+SEC Firmware and multiple loadable images
+=========================================
+
+Example FIT image description file demonstrating the usage
+of SEC Firmware and multiple loadable images loaded by U-Boot.
+For booting PPA (SEC Firmware), "firmware" is searched and loaded.
+
+Multiple binaries will be loaded as "loadables" (if present) at their
+respective load offsets from firmware image address.
+
+::
+
+    /dts-v1/;
+
+    /{
+        description = "PPA Firmware";
+        #address-cells = <1>;
+        images {
+            firmware@1 {
+                description = "PPA Firmware: <version>";
+                data = /incbin/("../obj/monitor.bin");
+                type = "firmware";
+                arch = "arm64";
+                compression = "none";
+            };
+            trustedOS@1 {
+                description = "Trusted OS";
+                data = /incbin/("../../tee.bin");
+                type = "OS";
+                arch = "arm64";
+                compression = "none";
+                load = <0x00200000>;
+            };
+            fuse_scr {
+                description = "Fuse Script";
+                data = /incbin/("../../fuse_scr.bin");
+                type = "firmware";
+                arch = "arm64";
+                compression = "none";
+                load = <0x00180000>;
+            };
+        };
+
+        configurations {
+            default = "config-1";
+            config-1 {
+                description = "PPA Secure firmware";
+                firmware = "firmware@1";
+                loadables = "trustedOS@1", "fuse_scr";
+            };
+        };
+    };
diff --git a/doc/usage/fit/sign-configs.rst b/doc/usage/fit/sign-configs.rst
new file mode 100644
index 00000000000..6a3df8f2c5b
--- /dev/null
+++ b/doc/usage/fit/sign-configs.rst
@@ -0,0 +1,52 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Signed configurations
+=====================
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "Chrome OS kernel image with one or more FDT blobs";
+        #address-cells = <1>;
+
+        images {
+            kernel {
+                data = /incbin/("test-kernel.bin");
+                type = "kernel_noload";
+                arch = "sandbox";
+                os = "linux";
+                compression = "lzo";
+                load = <0x4>;
+                entry = <0x8>;
+                kernel-version = <1>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+            fdt-1 {
+                description = "snow";
+                data = /incbin/("sandbox-kernel.dtb");
+                type = "flat_dt";
+                arch = "sandbox";
+                compression = "none";
+                fdt-version = <1>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+        };
+        configurations {
+            default = "conf-1";
+            conf-1 {
+                kernel = "kernel";
+                fdt = "fdt-1";
+                signature {
+                    algo = "sha1,rsa2048";
+                    key-name-hint = "dev";
+                    sign-images = "fdt", "kernel";
+                };
+            };
+        };
+    };
diff --git a/doc/usage/fit/sign-images.rst b/doc/usage/fit/sign-images.rst
new file mode 100644
index 00000000000..7d54d702c97
--- /dev/null
+++ b/doc/usage/fit/sign-images.rst
@@ -0,0 +1,49 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Signed Images
+=============
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "Chrome OS kernel image with one or more FDT blobs";
+        #address-cells = <1>;
+
+        images {
+            kernel {
+                data = /incbin/("test-kernel.bin");
+                type = "kernel_noload";
+                arch = "sandbox";
+                os = "linux";
+                compression = "none";
+                load = <0x4>;
+                entry = <0x8>;
+                kernel-version = <1>;
+                signature {
+                    algo = "sha1,rsa2048";
+                    key-name-hint = "dev";
+                };
+            };
+            fdt-1 {
+                description = "snow";
+                data = /incbin/("sandbox-kernel.dtb");
+                type = "flat_dt";
+                arch = "sandbox";
+                compression = "none";
+                fdt-version = <1>;
+                signature {
+                    algo = "sha1,rsa2048";
+                    key-name-hint = "dev";
+                };
+            };
+        };
+        configurations {
+            default = "conf-1";
+            conf-1 {
+                kernel = "kernel";
+                fdt = "fdt-1";
+            };
+        };
+    };
diff --git a/doc/usage/fit/signature.rst b/doc/usage/fit/signature.rst
new file mode 100644
index 00000000000..0804bffd1ed
--- /dev/null
+++ b/doc/usage/fit/signature.rst
@@ -0,0 +1,696 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+U-Boot FIT Signature Verification
+=================================
+
+Introduction
+------------
+
+FIT supports hashing of images so that these hashes can be checked on
+loading. This protects against corruption of the image. However it does not
+prevent the substitution of one image for another.
+
+The signature feature allows the hash to be signed with a private key such
+that it can be verified using a public key later. Provided that the private
+key is kept secret and the public key is stored in a non-volatile place,
+any image can be verified in this way.
+
+See verified-boot.txt for more general information on verified boot.
+
+
+Concepts
+--------
+
+Some familiarity with public key cryptography is assumed in this section.
+
+The procedure for signing is as follows:
+
+   - hash an image in the FIT
+   - sign the hash with a private key to produce a signature
+   - store the resulting signature in the FIT
+
+The procedure for verification is:
+
+   - read the FIT
+   - obtain the public key
+   - extract the signature from the FIT
+   - hash the image from the FIT
+   - verify (with the public key) that the extracted signature matches the
+     hash
+
+The signing is generally performed by mkimage, as part of making a firmware
+image for the device. The verification is normally done in U-Boot on the
+device.
+
+
+Algorithms
+----------
+In principle any suitable algorithm can be used to sign and verify a hash.
+U-Boot supports a few hashing and verification algorithms. See below for
+details.
+
+While it is acceptable to bring in large cryptographic libraries such as
+openssl on the host side (e.g. mkimage), it is not desirable for U-Boot.
+For the run-time verification side, it is important to keep code and data
+size as small as possible.
+
+For this reason the RSA image verification uses pre-processed public keys
+which can be used with a very small amount of code - just some extraction
+of data from the FDT and exponentiation mod n. Code size impact is a little
+under 5KB on Tegra Seaboard, for example.
+
+It is relatively straightforward to add new algorithms if required. If
+another RSA variant is needed, then it can be added with the
+U_BOOT_CRYPTO_ALGO() macro. If another algorithm is needed (such as DSA) then
+it can be placed in a directory alongside lib/rsa/, and its functions added
+using U_BOOT_CRYPTO_ALGO().
+
+
+Creating an RSA key pair and certificate
+----------------------------------------
+To create a new public/private key pair, size 2048 bits::
+
+    $ openssl genpkey -algorithm RSA -out keys/dev.key \
+        -pkeyopt rsa_keygen_bits:2048 -pkeyopt rsa_keygen_pubexp:65537
+
+To create a certificate for this containing the public key::
+
+    $ openssl req -batch -new -x509 -key keys/dev.key -out keys/dev.crt
+
+If you like you can look at the public key also::
+
+    $ openssl rsa -in keys/dev.key -pubout
+
+
+Public Key Storage
+------------------
+In order to verify an image that has been signed with a public key we need to
+have a trusted public key. This cannot be stored in the signed image, since
+it would be easy to alter. For this implementation we choose to store the
+public key in U-Boot's control FDT (using CONFIG_OF_CONTROL).
+
+Public keys should be stored as sub-nodes in a /signature node. Required
+properties are:
+
+algo
+    Algorithm name (e.g. "sha1,rsa2048" or "sha256,ecdsa256")
+
+Optional properties are:
+
+key-name-hint
+    Name of key used for signing. This is only a hint since it
+    is possible for the name to be changed. Verification can proceed by checking
+    all available signing keys until one matches.
+
+required
+    If present this indicates that the key must be verified for the
+    image / configuration to be considered valid. Only required keys are
+    normally verified by the FIT image booting algorithm. Valid values are
+    "image" to force verification of all images, and "conf" to force verification
+    of the selected configuration (which then relies on hashes in the images to
+    verify those).
+
+Each signing algorithm has its own additional properties.
+
+For RSA the following are mandatory:
+
+rsa,num-bits
+    Number of key bits (e.g. 2048)
+
+rsa,modulus
+    Modulus (N) as a big-endian multi-word integer
+
+rsa,exponent
+    Public exponent (E) as a 64 bit unsigned integer
+
+rsa,r-squared
+    (2^num-bits)^2 as a big-endian multi-word integer
+
+rsa,n0-inverse
+    -1 / modulus[0] mod 2^32
+
+For ECDSA the following are mandatory:
+
+ecdsa,curve
+    Name of ECDSA curve (e.g. "prime256v1")
+
+ecdsa,x-point
+    Public key X coordinate as a big-endian multi-word integer
+
+ecdsa,y-point
+    Public key Y coordinate as a big-endian multi-word integer
+
+These parameters can be added to a binary device tree using parameter -K of the
+mkimage command::
+
+    tools/mkimage -f fit.its -K control.dtb -k keys -r image.fit
+
+Here is an example of a generated device tree node::
+
+    signature {
+        key-dev {
+            required = "conf";
+            algo = "sha256,rsa2048";
+            rsa,r-squared = <0xb76d1acf 0xa1763ca5 0xeb2f126
+                    0x742edc80 0xd3f42177 0x9741d9d9
+                    0x35bb476e 0xff41c718 0xd3801430
+                    0xf22537cb 0xa7e79960 0xae32a043
+                    0x7da1427a 0x341d6492 0x3c2762f5
+                    0xaac04726 0x5b262d96 0xf984e86d
+                    0xb99443c7 0x17080c33 0x940f6892
+                    0xd57a95d1 0x6ea7b691 0xc5038fa8
+                    0x6bb48a6e 0x73f1b1ea 0x37160841
+                    0xe05715ce 0xa7c45bbd 0x690d82d5
+                    0x99c2454c 0x6ff117b3 0xd830683b
+                    0x3f81c9cf 0x1ca38a91 0x0c3392e4
+                    0xd817c625 0x7b8e9a24 0x175b89ea
+                    0xad79f3dc 0x4d50d7b4 0x9d4e90f8
+                    0xad9e2939 0xc165d6a4 0x0ada7e1b
+                    0xfb1bf495 0xfc3131c2 0xb8c6e604
+                    0xc2761124 0xf63de4a6 0x0e9565f9
+                    0xc8e53761 0x7e7a37a5 0xe99dcdae
+                    0x9aff7e1e 0xbd44b13d 0x6b0e6aa4
+                    0x038907e4 0x8e0d6850 0xef51bc20
+                    0xf73c94af 0x88bea7b1 0xcbbb1b30
+                    0xd024b7f3>;
+            rsa,modulus = <0xc0711d6cb 0x9e86db7f 0x45986dbe
+                       0x023f1e8c9 0xe1a4c4d0 0x8a0dfdc9
+                       0x023ba0c48 0x06815f6a 0x5caa0654
+                       0x07078c4b7 0x3d154853 0x40729023
+                       0x0b007c8fe 0x5a3647e5 0x23b41e20
+                       0x024720591 0x66915305 0x0e0b29b0
+                       0x0de2ad30d 0x8589430f 0xb1590325
+                       0x0fb9f5d5e 0x9eba752a 0xd88e6de9
+                       0x056b3dcc6 0x9a6b8e61 0x6784f61f
+                       0x000f39c21 0x5eec6b33 0xd78e4f78
+                       0x0921a305f 0xaa2cc27e 0x1ca917af
+                       0x06e1134f4 0xd48cac77 0x4e914d07
+                       0x0f707aa5a 0x0d141f41 0x84677f1d
+                       0x0ad47a049 0x028aedb6 0xd5536fcf
+                       0x03fef1e4f 0x133a03d2 0xfd7a750a
+                       0x0f9159732 0xd207812e 0x6a807375
+                       0x06434230d 0xc8e22dad 0x9f29b3d6
+                       0x07c44ac2b 0xfa2aad88 0xe2429504
+                       0x041febd41 0x85d0d142 0x7b194d65
+                       0x06e5d55ea 0x41116961 0xf3181dde
+                       0x068bf5fbc 0x3dd82047 0x00ee647e
+                       0x0d7a44ab3>;
+            rsa,exponent = <0x00 0x10001>;
+            rsa,n0-inverse = <0xb3928b85>;
+            rsa,num-bits = <0x800>;
+            key-name-hint = "dev";
+        };
+    };
+
+
+Signed Configurations
+---------------------
+While signing images is useful, it does not provide complete protection
+against several types of attack. For example, it is possible to create a
+FIT with the same signed images, but with the configuration changed such
+that a different one is selected (mix and match attack). It is also possible
+to substitute a signed image from an older FIT version into a newer FIT
+(roll-back attack).
+
+As an example, consider this FIT::
+
+    / {
+        images {
+            kernel-1 {
+                data = <data for kernel1>
+                signature-1 {
+                    algo = "sha1,rsa2048";
+                    value = <...kernel signature 1...>
+                };
+            };
+            kernel-2 {
+                data = <data for kernel2>
+                signature-1 {
+                    algo = "sha1,rsa2048";
+                    value = <...kernel signature 2...>
+                };
+            };
+            fdt-1 {
+                data = <data for fdt1>;
+                signature-1 {
+                    algo = "sha1,rsa2048";
+                    value = <...fdt signature 1...>
+                };
+            };
+            fdt-2 {
+                data = <data for fdt2>;
+                signature-1 {
+                    algo = "sha1,rsa2048";
+                    value = <...fdt signature 2...>
+                };
+            };
+        };
+        configurations {
+            default = "conf-1";
+            conf-1 {
+                kernel = "kernel-1";
+                fdt = "fdt-1";
+            };
+            conf-2 {
+                kernel = "kernel-2";
+                fdt = "fdt-2";
+            };
+        };
+    };
+
+Since both kernels are signed it is easy for an attacker to add a new
+configuration 3 with kernel 1 and fdt 2::
+
+    configurations {
+        default = "conf-1";
+        conf-1 {
+            kernel = "kernel-1";
+            fdt = "fdt-1";
+        };
+        conf-2 {
+            kernel = "kernel-2";
+            fdt = "fdt-2";
+        };
+        conf-3 {
+            kernel = "kernel-1";
+            fdt = "fdt-2";
+        };
+    };
+
+With signed images, nothing protects against this. Whether it gains an
+advantage for the attacker is debatable, but it is not secure.
+
+To solve this problem, we support signed configurations. In this case it
+is the configurations that are signed, not the image. Each image has its
+own hash, and we include the hash in the configuration signature.
+
+So the above example is adjusted to look like this::
+
+    / {
+        images {
+            kernel-1 {
+                data = <data for kernel1>
+                hash-1 {
+                    algo = "sha1";
+                    value = <...kernel hash 1...>
+                };
+            };
+            kernel-2 {
+                data = <data for kernel2>
+                hash-1 {
+                    algo = "sha1";
+                    value = <...kernel hash 2...>
+                };
+            };
+            fdt-1 {
+                data = <data for fdt1>;
+                hash-1 {
+                    algo = "sha1";
+                    value = <...fdt hash 1...>
+                };
+            };
+            fdt-2 {
+                data = <data for fdt2>;
+                hash-1 {
+                    algo = "sha1";
+                    value = <...fdt hash 2...>
+                };
+            };
+        };
+        configurations {
+            default = "conf-1";
+            conf-1 {
+                kernel = "kernel-1";
+                fdt = "fdt-1";
+                signature-1 {
+                    algo = "sha1,rsa2048";
+                    value = <...conf 1 signature...>;
+                };
+            };
+            conf-2 {
+                kernel = "kernel-2";
+                fdt = "fdt-2";
+                signature-1 {
+                    algo = "sha1,rsa2048";
+                    value = <...conf 1 signature...>;
+                };
+            };
+        };
+    };
+
+
+You can see that we have added hashes for all images (since they are no
+longer signed), and a signature to each configuration. In the above example,
+mkimage will sign configurations/conf-1, the kernel and fdt that are
+pointed to by the configuration (/images/kernel-1, /images/kernel-1/hash-1,
+/images/fdt-1, /images/fdt-1/hash-1) and the root structure of the image
+(so that it isn't possible to add or remove root nodes). The signature is
+written into /configurations/conf-1/signature-1/value. It can easily be
+verified later even if the FIT has been signed with other keys in the
+meantime.
+
+
+Details
+-------
+The signature node contains a property ('hashed-nodes') which lists all the
+nodes that the signature was made over.  The image is walked in order and each
+tag processed as follows:
+
+DTB_BEGIN_NODE
+    The tag and the following name are included in the signature
+    if the node or its parent are present in 'hashed-nodes'
+
+DTB_END_NODE
+    The tag is included in the signature if the node or its parent
+    are present in 'hashed-nodes'
+
+DTB_PROPERTY
+    The tag, the length word, the offset in the string table, and
+    the data are all included if the current node is present in 'hashed-nodes'
+    and the property name is not 'data'.
+
+DTB_END
+    The tag is always included in the signature.
+
+DTB_NOP
+    The tag is included in the signature if the current node is present
+    in 'hashed-nodes'
+
+In addition, the signature contains a property 'hashed-strings' which contains
+the offset and length in the string table of the strings that are to be
+included in the signature (this is done last).
+
+IMPORTANT:  To verify the signature outside u-boot, it is vital to not only
+calculate the hash of the image and verify the signature with that, but also to
+calculate the hashes of the kernel, fdt, and ramdisk images and check those
+match the hash values in the corresponding 'hash*' subnodes.
+
+
+Verification
+------------
+FITs are verified when loaded. After the configuration is selected a list
+of required images is produced. If there are 'required' public keys, then
+each image must be verified against those keys. This means that every image
+that might be used by the target needs to be signed with 'required' keys.
+
+This happens automatically as part of a bootm command when FITs are used.
+
+For Signed Configurations, the default verification behavior can be changed by
+the following optional property in /signature node in U-Boot's control FDT.
+
+required-mode
+    Valid values are "any" to allow verified boot to succeed if
+    the selected configuration is signed by any of the 'required' keys, and "all"
+    to allow verified boot to succeed if the selected configuration is signed by
+    all of the 'required' keys.
+
+This property can be added to a binary device tree using fdtput as shown in
+below examples::
+
+    fdtput -t s control.dtb /signature required-mode any
+    fdtput -t s control.dtb /signature required-mode all
+
+
+Enabling FIT Verification
+-------------------------
+In addition to the options to enable FIT itself, the following CONFIGs must
+be enabled:
+
+CONFIG_FIT_SIGNATURE
+    enable signing and verification in FITs
+
+CONFIG_RSA
+    enable RSA algorithm for signing
+
+CONFIG_ECDSA
+    enable ECDSA algorithm for signing
+
+WARNING: When relying on signed FIT images with required signature check
+the legacy image format is default disabled by not defining
+CONFIG_LEGACY_IMAGE_FORMAT
+
+
+Testing
+-------
+
+An easy way to test signing and verification is to use the test script
+provided in test/vboot/vboot_test.sh. This uses sandbox (a special version
+of U-Boot which runs under Linux) to show the operation of a 'bootm'
+command loading and verifying images.
+
+A sample run is show below::
+
+    $ make O=sandbox sandbox_config
+    $ make O=sandbox
+    $ O=sandbox ./test/vboot/vboot_test.sh
+
+
+Simple Verified Boot Test
+-------------------------
+
+Please see :doc:`verified-boot` for more information::
+
+    /home/hs/ids/u-boot/sandbox/tools/mkimage -D -I dts -O dtb -p 2000
+    Build keys
+    do sha1 test
+    Build FIT with signed images
+    Test Verified Boot Run: unsigned signatures:: OK
+    Sign images
+    Test Verified Boot Run: signed images: OK
+    Build FIT with signed configuration
+    Test Verified Boot Run: unsigned config: OK
+    Sign images
+    Test Verified Boot Run: signed config: OK
+    check signed config on the host
+    Signature check OK
+    OK
+    Test Verified Boot Run: signed config: OK
+    Test Verified Boot Run: signed config with bad hash: OK
+    do sha256 test
+    Build FIT with signed images
+    Test Verified Boot Run: unsigned signatures:: OK
+    Sign images
+    Test Verified Boot Run: signed images: OK
+    Build FIT with signed configuration
+    Test Verified Boot Run: unsigned config: OK
+    Sign images
+    Test Verified Boot Run: signed config: OK
+    check signed config on the host
+    Signature check OK
+    OK
+    Test Verified Boot Run: signed config: OK
+    Test Verified Boot Run: signed config with bad hash: OK
+
+    Test passed
+
+
+Software signing: keydir vs keyfile
+-----------------------------------
+
+In the simplest case, signing is done by giving mkimage the 'keyfile'. This is
+the path to a file containing the signing key.
+
+The alternative is to pass the 'keydir' argument. In this case the filename of
+the key is derived from the 'keydir' and the "key-name-hint" property in the
+FIT. In this case the "key-name-hint" property is mandatory, and the key must
+exist in "<keydir>/<key-name-hint>.<ext>" Here the extension "ext" is
+specific to the signing algorithm.
+
+
+Hardware Signing with PKCS#11 or with HSM
+-----------------------------------------
+
+Securely managing private signing keys can challenging, especially when the
+keys are stored on the file system of a computer that is connected to the
+Internet. If an attacker is able to steal the key, they can sign malicious FIT
+images which will appear genuine to your devices.
+
+An alternative solution is to keep your signing key securely stored on hardware
+device like a smartcard, USB token or Hardware Security Module (HSM) and have
+them perform the signing. PKCS#11 is standard for interfacing with these crypto
+device.
+
+Requirements:
+    - Smartcard/USB token/HSM which can work with some openssl engine
+    - openssl
+
+For pkcs11 engine usage:
+    - libp11 (provides pkcs11 engine)
+    - p11-kit (recommended to simplify setup)
+    - opensc (for smartcards and smartcard like USB devices)
+    - gnutls (recommended for key generation, p11tool)
+
+For generic HSMs respective openssl engine must be installed and locateable by
+openssl. This may require setting up LD_LIBRARY_PATH if engine is not installed
+to openssl's default search paths.
+
+PKCS11 engine support forms "key id" based on "keydir" and with
+"key-name-hint". "key-name-hint" is used as "object" name (if not defined in
+keydir). "keydir" (if defined) is used to define (prefix for) which PKCS11 source
+is being used for lookup up for the key.
+
+PKCS11 engine key ids
+    "pkcs11:<keydir>;object=<key-name-hint>;type=<public|private>"
+
+or, if keydir contains "object="
+    "pkcs11:<keydir>;type=<public|private>"
+
+or
+    "pkcs11:object=<key-name-hint>;type=<public|private>",
+
+Generic HSM engine support forms "key id" based on "keydir" and with
+"key-name-hint". If "keydir" is specified for mkimage it is used as a prefix in
+"key id" and is appended with "key-name-hint".
+
+Generic engine key ids:
+    "<keydir><key-name-hint>"
+
+or
+    "<  key-name-hint>"
+
+In order to set the pin in the HSM, an environment variable "MKIMAGE_SIGN_PIN"
+can be specified.
+
+The following examples use the Nitrokey Pro using pkcs11 engine. Instructions
+for other devices may vary.
+
+Notes on pkcs11 engine setup:
+
+Make sure p11-kit, opensc are installed and that p11-kit is setup to use opensc.
+/usr/share/p11-kit/modules/opensc.module should be present on your system.
+
+
+Generating Keys On the Nitrokey::
+
+    $ gpg --card-edit
+
+    Reader ...........: Nitrokey Nitrokey Pro (xxxxxxxx0000000000000000) 00 00
+    Application ID ...: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+    Version ..........: 2.1
+    Manufacturer .....: ZeitControl
+    Serial number ....: xxxxxxxx
+    Name of cardholder: [not set]
+    Language prefs ...: de
+    Sex ..............: unspecified
+    URL of public key : [not set]
+    Login data .......: [not set]
+    Signature PIN ....: forced
+    Key attributes ...: rsa2048 rsa2048 rsa2048
+    Max. PIN lengths .: 32 32 32
+    PIN retry counter : 3 0 3
+    Signature counter : 0
+    Signature key ....: [none]
+    Encryption key....: [none]
+    Authentication key: [none]
+    General key info..: [none]
+
+    gpg/card> generate
+    Make off-card backup of encryption key? (Y/n) n
+
+    Please note that the factory settings of the PINs are
+    PIN = '123456' Admin PIN = '12345678'
+    You should change them using the command --change-pin
+
+    What keysize do you want for the Signature key? (2048) 4096
+    The card will now be re-configured to generate a key of 4096 bits
+    Note: There is no guarantee that the card supports the requested size.
+    If the key generation does not succeed, please check the
+    documentation of your card to see what sizes are allowed.
+    What keysize do you want for the Encryption key? (2048) 4096
+    The card will now be re-configured to generate a key of 4096 bits
+    What keysize do you want for the Authentication key? (2048) 4096
+    The card will now be re-configured to generate a key of 4096 bits
+    Please specify how long the key should be valid.
+    0 = key does not expire
+    <n> = key expires in n days
+    <n>w = key expires in n weeks
+    <n>m = key expires in n months
+    <n>y = key expires in n years
+    Key is valid for? (0)
+    Key does not expire at all
+    Is this correct? (y/N) y
+
+    GnuPG needs to construct a user ID to identify your key.
+
+    Real name: John Doe
+    Email address: [email protected]
+    Comment:
+    You selected this USER-ID:
+    "John Doe <[email protected]>"
+
+    Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
+
+
+Using p11tool to get the token URL:
+
+Depending on system configuration, gpg-agent may need to be killed first::
+
+    $ p11tool --provider /usr/lib/opensc-pkcs11.so --list-tokens
+    Token 0:
+    URL: pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29
+    Label: OpenPGP card (User PIN (sig))
+    Type: Hardware token
+    Manufacturer: ZeitControl
+    Model: PKCS#15 emulated
+    Serial: 000xxxxxxxxx
+    Module: (null)
+
+
+    Token 1:
+    URL: pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%29
+    Label: OpenPGP card (User PIN)
+    Type: Hardware token
+    Manufacturer: ZeitControl
+    Model: PKCS#15 emulated
+    Serial: 000xxxxxxxxx
+    Module: (null)
+
+Use the portion of the signature token URL after "pkcs11:" as the keydir argument (-k) to mkimage below.
+
+
+Use the URL of the token to list the private keys::
+
+    $ p11tool --login --provider /usr/lib/opensc-pkcs11.so --list-privkeys \
+    "pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29"
+    Token 'OpenPGP card (User PIN (sig))' with URL 'pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29' requires user PIN
+    Enter PIN:
+    Object 0:
+    URL: pkcs11:model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29;id=%01;object=Signature%20key;type=private
+    Type: Private key
+    Label: Signature key
+    Flags: CKA_PRIVATE; CKA_NEVER_EXTRACTABLE; CKA_SENSITIVE;
+    ID: 01
+
+Use the label, in this case "Signature key" as the key-name-hint in your FIT.
+
+Create the fitImage::
+
+    $ ./tools/mkimage -f fit-image.its fitImage
+
+
+Sign the fitImage with the hardware key::
+
+    $ ./tools/mkimage -F -k \
+    "model=PKCS%2315%20emulated;manufacturer=ZeitControl;serial=000xxxxxxxxx;token=OpenPGP%20card%20%28User%20PIN%20%28sig%29%29" \
+    -K u-boot.dtb -N pkcs11 -r fitImage
+
+
+Future Work
+-----------
+
+- Roll-back protection using a TPM is done using the tpm command. This can
+  be scripted, but we might consider a default way of doing this, built into
+  bootm.
+
+
+Possible Future Work
+--------------------
+
+- More sandbox tests for failure modes
+- Passwords for keys/certificates
+- Perhaps implement OAEP
+- Enhance bootm to permit scripted signature verification (so that a script
+  can verify an image but not actually boot it)
+
+
+.. sectionauthor:: Simon Glass <[email protected]>, 1-1-13
diff --git a/doc/usage/fit/source_file_format.rst b/doc/usage/fit/source_file_format.rst
new file mode 100644
index 00000000000..b2b1e42bd73
--- /dev/null
+++ b/doc/usage/fit/source_file_format.rst
@@ -0,0 +1,684 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Flattened Image Tree (FIT) Format
+=================================
+
+Introduction
+------------
+
+The number of elements playing a role in the kernel booting process has
+increased over time and now typically includes the devicetree, kernel image and
+possibly a ramdisk image. Generally, all must be placed in the system memory and
+booted together.
+
+For firmware images a similar process has taken place, with various binaries
+loaded at different addresses, such as ARM's ATF, OpenSBI, FPGA and U-Boot
+itself.
+
+FIT provides a flexible and extensible format to deal with this complexity. It
+provides support for multiple components. It also supports multiple
+configurations, so that the same FIT can be used to boot multiple boards, with
+some components in common (e.g. kernel) and some specific to that board (e.g.
+devicetree).
+
+Terminology
+~~~~~~~~~~~
+
+This document defines FIT by providing FDT (Flat Device Tree) bindings. These
+describe the final form of the FIT at the moment when it is used. The user
+perspective may be simpler, as some of the properties (like timestamps and
+hashes) are filled in automatically by the U-Boot mkimage tool.
+
+To avoid confusion with the kernel FDT the following naming convention is used:
+
+FIT
+    Flattened Image Tree
+
+FIT is formally a flattened devicetree (in the libfdt meaning), which conforms
+to bindings defined in this document.
+
+.its
+    image tree source
+
+.itb
+    flattened image tree blob
+
+Image-building procedure
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+The following picture shows how the FIT is prepared. Input consists of
+image source file (.its) and a set of data files. Image is created with the
+help of standard U-Boot mkimage tool which in turn uses dtc (device tree
+compiler) to produce image tree blob (.itb). The resulting .itb file is the
+actual binary of a new FIT::
+
+    tqm5200.its
+    +
+    vmlinux.bin.gz     mkimage + dtc               xfer to target
+    eldk-4.2-ramdisk  --------------> tqm5200.itb --------------> boot
+    tqm5200.dtb                          /|\
+                                          |
+                                     'new FIT'
+
+Steps:
+
+#. Create .its file, automatically filled-in properties are omitted
+
+#. Call mkimage tool on a .its file
+
+#. mkimage calls dtc to create .itb image and assures that
+   missing properties are added
+
+#. .itb (new FIT) is uploaded onto the target and used therein
+
+
+Unique identifiers
+~~~~~~~~~~~~~~~~~~
+
+To identify FIT sub-nodes representing images, hashes, configurations (which
+are defined in the following sections), the "unit name" of the given sub-node
+is used as it's identifier as it assures uniqueness without additional
+checking required.
+
+
+External data
+~~~~~~~~~~~~~
+
+FIT is normally built initially with image data in the 'data' property of each
+image node. It is also possible for this data to reside outside the FIT itself.
+This allows the 'FDT' part of the FIT to be quite small, so that it can be
+loaded and scanned without loading a large amount of data. Then when an image is
+needed it can be loaded from an external source.
+
+External FITs use 'data-offset' or 'data-position' instead of 'data'.
+
+The mkimage tool can convert a FIT to use external data using the `-E` argument,
+optionally using `-p` to specific a fixed position.
+
+It is often desirable to align each image to a block size or cache-line size
+(e.g. 512 bytes), so that there is no need to copy it to an aligned address when
+reading the image data. The mkimage tool provides a `-B` argument to support
+this.
+
+Root-node properties
+--------------------
+
+The root node of the FIT should have the following layout::
+
+    / o image-tree
+        |- description = "image description"
+        |- timestamp = <12399321>
+        |- #address-cells = <1>
+        |
+        o images
+        | |
+        | o image-1 {...}
+        | o image-2 {...}
+        | ...
+        |
+        o configurations
+          |- default = "conf-1"
+          |
+          o conf-1 {...}
+          o conf-2 {...}
+          ...
+
+Optional property
+~~~~~~~~~~~~~~~~~
+
+description
+    Textual description of the FIT
+
+Mandatory property
+~~~~~~~~~~~~~~~~~~
+
+timestamp
+    Last image modification time being counted in seconds since
+    1970-01-01 00:00:00 - to be automatically calculated by mkimage tool.
+
+Conditionally mandatory property
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+#address-cells
+    Number of 32bit cells required to represent entry and
+    load addresses supplied within sub-image nodes. May be omitted when no
+    entry or load addresses are used.
+
+Mandatory nodes
+~~~~~~~~~~~~~~~
+
+images
+    This node contains a set of sub-nodes, each of them representing
+    single component sub-image (like kernel, ramdisk, etc.). At least one
+    sub-image is required.
+
+configurations
+    Contains a set of available configuration nodes and
+    defines a default configuration.
+
+
+'/images' node
+--------------
+
+This node is a container node for component sub-image nodes. Each sub-node of
+the '/images' node should have the following layout::
+
+    o image-1
+        |- description = "component sub-image description"
+        |- data = /incbin/("path/to/data/file.bin")
+        |- type = "sub-image type name"
+        |- arch = "ARCH name"
+        |- os = "OS name"
+        |- compression = "compression name"
+        |- load = <00000000>
+        |- entry = <00000000>
+        |
+        o hash-1 {...}
+        o hash-2 {...}
+        ...
+
+Mandatory properties
+~~~~~~~~~~~~~~~~~~~~
+
+description
+    Textual description of the component sub-image
+
+type
+    Name of component sub-image type. Supported types are:
+
+    ====================  ==================
+    Sub-image type        Meaning
+    ====================  ==================
+    invalid               Invalid Image
+    aisimage              Davinci AIS image
+    atmelimage            ATMEL ROM-Boot Image
+    copro                 Coprocessor Image}
+    fdt_legacy            legacy Image with Flat Device Tree
+    filesystem            Filesystem Image
+    firmware              Firmware
+    firmware_ivt          Firmware with HABv4 IVT }
+    flat_dt               Flat Device Tree
+    fpga                  FPGA Image }
+    gpimage               TI Keystone SPL Image
+    imx8image             NXP i.MX8 Boot Image
+    imx8mimage            NXP i.MX8M Boot Image
+    imximage              Freescale i.MX Boot Image
+    kernel                Kernel Image
+    kernel_noload         Kernel Image (no loading done)
+    kwbimage              Kirkwood Boot Image
+    lpc32xximage          LPC32XX Boot Image
+    mtk_image             MediaTek BootROM loadable Image }
+    multi                 Multi-File Image
+    mxsimage              Freescale MXS Boot Image
+    omapimage             TI OMAP SPL With GP CH
+    pblimage              Freescale PBL Boot Image
+    pmmc                  TI Power Management Micro-Controller Firmware
+    ramdisk               RAMDisk Image
+    rkimage               Rockchip Boot Image }
+    rksd                  Rockchip SD Boot Image }
+    rkspi                 Rockchip SPI Boot Image }
+    script                Script
+    socfpgaimage          Altera SoCFPGA CV/AV preloader
+    socfpgaimage_v1       Altera SoCFPGA A10 preloader
+    spkgimage             Renesas SPKG Image }
+    standalone            Standalone Program
+    stm32image            STMicroelectronics STM32 Image }
+    sunxi_egon            Allwinner eGON Boot Image }
+    sunxi_toc0            Allwinner TOC0 Boot Image }
+    tee                   Trusted Execution Environment Image
+    ublimage              Davinci UBL image
+    vybridimage           Vybrid Boot Image
+    x86_setup             x86 setup.bin
+    zynqimage             Xilinx Zynq Boot Image }
+    zynqmpbif             Xilinx ZynqMP Boot Image (bif) }
+    zynqmpimage           Xilinx ZynqMP Boot Image }
+    ====================  ==================
+
+compression
+    Compression used by included data. If no compression is used, the
+    compression property should be set to "none". If the data is compressed but
+    it should not be uncompressed by the loader (e.g. compressed ramdisk), this
+    should also be set to "none".
+
+    Supported compression types are:
+
+    ====================  ==================
+    Compression type      Meaning
+    ====================  ==================
+    none                  uncompressed
+    bzip2                 bzip2 compressed
+    gzip                  gzip compressed
+    lz4                   lz4 compressed
+    lzma                  lzma compressed
+    lzo                   lzo compressed
+    zstd                  zstd compressed
+    ====================  ==================
+
+data-size
+    size of the data in bytes
+
+
+Conditionally mandatory property
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+data
+    Path to the external file which contains this node's binary data. Within
+    the FIT this is the contents of the file. This is mandatory unless
+    external data is used.
+
+data-offset
+    Offset of the data in a separate image store. The image store is placed
+    immediately after the last byte of the device tree binary, aligned to a
+    4-byte boundary. This is mandatory if external data is used, with an offset.
+
+data-position
+    Machine address at which the data is to be found. This is a fixed address
+    not relative to the loading of the FIT. This is mandatory if external data
+    used with a fixed address.
+
+os
+    OS name, mandatory for types "kernel". Valid OS names are:
+
+    ====================  ==================
+    OS name               Meaning
+    ====================  ==================
+    invalid               Invalid OS
+    4_4bsd                4_4BSD
+    arm-trusted-firmware  ARM Trusted Firmware
+    dell                  Dell
+    efi                   EFI Firmware
+    esix                  Esix
+    freebsd               FreeBSD
+    integrity             INTEGRITY
+    irix                  Irix
+    linux                 Linux
+    ncr                   NCR
+    netbsd                NetBSD
+    openbsd               OpenBSD
+    openrtos              OpenRTOS
+    opensbi               RISC-V OpenSBI
+    ose                   Enea OSE
+    plan9                 Plan 9
+    psos                  pSOS
+    qnx                   QNX
+    rtems                 RTEMS
+    sco                   SCO
+    solaris               Solaris
+    svr4                  SVR4
+    tee                   Trusted Execution Environment
+    u-boot                U-Boot
+    vxworks               VxWorks
+    ====================  ==================
+
+arch
+    Architecture name, mandatory for types: "standalone", "kernel",
+    "firmware", "ramdisk" and "fdt". Valid architecture names are:
+
+    ====================  ==================
+    Architecture type     Meaning
+    ====================  ==================
+    invalid               Invalid ARCH
+    alpha                 Alpha
+    arc                   ARC
+    arm64                 AArch64
+    arm                   ARM
+    avr32                 AVR32
+    blackfin              Blackfin
+    ia64                  IA64
+    m68k                  M68K
+    microblaze            MicroBlaze
+    mips64                MIPS 64 Bit
+    mips                  MIPS
+    nds32                 NDS32
+    nios2                 NIOS II
+    or1k                  OpenRISC 1000
+    powerpc               PowerPC
+    ppc                   PowerPC
+    riscv                 RISC-V
+    s390                  IBM S390
+    sandbox               Sandbox
+    sh                    SuperH
+    sparc64               SPARC 64 Bit
+    sparc                 SPARC
+    x86_64                AMD x86_64
+    x86                   Intel x86
+    xtensa                Xtensa
+    ====================  ==================
+
+entry
+    entry point address, address size is determined by
+    '#address-cells' property of the root node.
+    Mandatory for types: "firmware", and "kernel".
+
+load
+    load address, address size is determined by '#address-cells'
+    property of the root node.
+    Mandatory for types: "firmware", and "kernel".
+
+compatible
+    compatible method for loading image.
+    Mandatory for types: "fpga", and images that do not specify a load address.
+    Supported compatible methods:
+
+    ==========================  =========================================
+    Compatible string           Meaning
+    ==========================  =========================================
+    u-boot,fpga-legacy          Generic fpga loading routine.
+    u-boot,zynqmp-fpga-ddrauth  Signed non-encrypted FPGA bitstream for
+                                Xilinx Zynq UltraScale+ (ZymqMP) device.
+    u-boot,zynqmp-fpga-enc      Encrypted FPGA bitstream for Xilinx Zynq
+                                UltraScale+ (ZynqMP) device.
+    ==========================  =========================================
+
+phase
+    U-Boot phase for which the image is intended.
+
+    "spl"
+        image is an SPL image
+
+    "u-boot"
+        image is a U-Boot image
+
+Optional nodes:
+
+hash-1
+    Each hash sub-node represents separate hash or checksum
+    calculated for node's data according to specified algorithm.
+
+signature-1
+    Each signature sub-node represents separate signature
+    calculated for node's data according to specified algorithm.
+
+
+Hash nodes
+----------
+
+::
+
+    o hash-1
+        |- algo = "hash or checksum algorithm name"
+        |- value = [hash or checksum value]
+
+Mandatory properties
+~~~~~~~~~~~~~~~~~~~~
+
+algo
+    Algorithm name. Supported algoriths and their value sizes are:
+
+    ==================== ============ =========================================
+    Sub-image type       Size (bytes) Meaning
+    ==================== ============ =========================================
+    crc16-ccitt          2            Cyclic Redundancy Check 16-bit
+                                      (Consultative Committee for International
+                                      Telegraphy and Telephony)
+    crc32                4            Cyclic Redundancy Check 32-bit
+    md5                  16           Message Digest 5 (MD5)
+    sha1                 20           Secure Hash Algorithm 1 (SHA1)
+    sha256               32           Secure Hash Algorithm 2 (SHA256)
+    sha384               48           Secure Hash Algorithm 2 (SHA384)
+    sha512               64           Secure Hash Algorithm 2 (SHA512)
+    ==================== ============ =========================================
+
+value
+    Actual checksum or hash value.
+
+Image-signature nodes
+---------------------
+
+::
+
+    o signature-1
+        |- algo = "algorithm name"
+        |- key-name-hint = "key name"
+        |- value = [hash or checksum value]
+
+
+Mandatory properties
+~~~~~~~~~~~~~~~~~~~~
+
+_`FIT Algorithm`:
+
+algo
+    Algorithm name. Supported algoriths and their value sizes are shown below.
+    Note that the hash is specified separately from the signing algorithm, so
+    it is possible to mix and match any SHA algorithm with any signing
+    algorithm. The size of the signature relates to the signing algorithm, not
+    the hash, since it is the hash that is signed.
+
+    ==================== ============ =========================================
+    Sub-image type       Size (bytes) Meaning
+    ==================== ============ =========================================
+    sha1,rsa2048         256          SHA1 hash signed with 2048-bit
+                                      Rivest–Shamir–Adleman algorithm
+    sha1,rsa3072         384          SHA1 hash signed with 2048-bit RSA
+    sha1,rsa4096         512          SHA1 hash signed with 2048-bit RSA
+    sha1,ecdsa256        32           SHA1 hash signed with 256-bit  Elliptic
+                                      Curve Digital Signature Algorithm
+    sha256,...
+    sha384,...
+    sha512,...
+    ==================== ============ =========================================
+
+key-name-hint
+    Name of key to use for signing. The keys will normally be in
+    a single directory (parameter -k to mkimage). For a given key <name>, its
+    private key is stored in <name>.key and the certificate is stored in
+    <name>.crt.
+
+sign-images
+    A list of images to sign, each being a property of the conf
+    node that contains then. The default is "kernel,fdt" which means that these
+    two images will be looked up in the config and signed if present. This is
+    used by mkimage to determine which images to sign.
+
+The following properies are added as part of signing, and are mandatory:
+
+value
+    Actual signature value. This is added by mkimage.
+
+hashed-nodes
+    A list of nodes which were hashed by the signer. Each is
+    a string - the full path to node. A typical value might be::
+
+	hashed-nodes = "/", "/configurations/conf-1", "/images/kernel",
+	    "/images/kernel/hash-1", "/images/fdt-1",
+	    "/images/fdt-1/hash-1";
+
+hashed-strings
+    The start and size of the string region of the FIT that was hashed. The
+    start is normally 0, indicating the first byte of the string table. The size
+    indicates the number of bytes hashed as part of signing.
+
+The following properies are added as part of signing, and are optional:
+
+timestamp
+    Time when image was signed (standard Unix time_t format)
+
+signer-name
+    Name of the signer (e.g. "mkimage")
+
+signer-version
+    Version string of the signer (e.g. "2013.01")
+
+comment
+    Additional information about the signer or image
+
+padding
+    The padding algorithm, it may be pkcs-1.5 or pss,
+    if no value is provided we assume pkcs-1.5
+
+
+'/configurations' node
+----------------------
+
+The 'configurations' node creates convenient, labeled boot configurations,
+which combine together kernel images with their ramdisks and fdt blobs.
+
+The 'configurations' node has the following structure::
+
+    o configurations
+        |- default = "default configuration sub-node unit name"
+        |
+        o config-1 {...}
+        o config-2 {...}
+        ...
+
+
+Optional property
+~~~~~~~~~~~~~~~~~
+
+default
+    Selects one of the configuration sub-nodes as a default configuration.
+
+Mandatory nodes
+~~~~~~~~~~~~~~~
+
+configuration-sub-node-unit-name
+    At least one of the configuration sub-nodes is required.
+
+Optional nodes
+~~~~~~~~~~~~~~
+
+signature-1
+    Each signature sub-node represents separate signature
+    calculated for the configuration according to specified algorithm.
+
+
+Configuration nodes
+-------------------
+
+Each configuration has the following structure::
+
+    o config-1
+        |- description = "configuration description"
+        |- kernel = "kernel sub-node unit name"
+        |- fdt = "fdt sub-node unit-name" [, "fdt overlay sub-node unit-name", ...]
+        |- loadables = "loadables sub-node unit-name"
+        |- script = "
+        |- compatible = "vendor,board-style device tree compatible string"
+        o signature-1 {...}
+
+Mandatory properties
+~~~~~~~~~~~~~~~~~~~~
+
+description
+    Textual configuration description.
+
+kernel or firmware
+    Unit name of the corresponding kernel or firmware
+    (u-boot, op-tee, etc) image. If both "kernel" and "firmware" are specified,
+    control is passed to the firmware image.
+
+Optional properties
+~~~~~~~~~~~~~~~~~~~
+
+fdt
+    Unit name of the corresponding fdt blob (component image node of a
+    "fdt type"). Additional fdt overlay nodes can be supplied which signify
+    that the resulting device tree blob is generated by the first base fdt
+    blob with all subsequent overlays applied.
+
+fpga
+    Unit name of the corresponding fpga bitstream blob
+    (component image node of a "fpga type").
+
+loadables
+    Unit name containing a list of additional binaries to be
+    loaded at their given locations.  "loadables" is a comma-separated list
+    of strings. U-Boot will load each binary at its given start-address and
+    may optionally invoke additional post-processing steps on this binary based
+    on its component image node type.
+
+script
+    The image to use when loading a U-Boot script (for use with the
+    source command).
+
+compatible
+    The root compatible string of the U-Boot device tree that
+    this configuration shall automatically match when CONFIG_FIT_BEST_MATCH is
+    enabled. If this property is not provided, the compatible string will be
+    extracted from the fdt blob instead. This is only possible if the fdt is
+    not compressed, so images with compressed fdts that want to use compatible
+    string matching must always provide this property.
+
+The FDT blob is required to properly boot FDT based kernel, so the minimal
+configuration for 2.6 FDT kernel is (kernel, fdt) pair.
+
+Older, 2.4 kernel and 2.6 non-FDT kernel do not use FDT blob, in such cases
+'struct bd_info' must be passed instead of FDT blob, thus fdt property *must
+not* be specified in a configuration node.
+
+Configuration-signature nodes
+-----------------------------
+
+::
+
+    o signature-1
+        |- algo = "algorithm name"
+        |- key-name-hint = "key name"
+        |- sign-images = "path1", "path2";
+        |- value = [hash or checksum value]
+        |- hashed-strings = <0 len>
+
+
+Mandatory properties
+~~~~~~~~~~~~~~~~~~~~
+
+algo
+    See `FIT Algorithm`_.
+
+key-name-hint
+    Name of key to use for signing. The keys will normally be in
+    a single directory (parameter -k to mkimage). For a given key <name>, its
+    private key is stored in <name>.key and the certificate is stored in
+    <name>.crt.
+
+The following properies are added as part of signing, and are mandatory:
+
+value
+    Actual signature value. This is added by mkimage.
+
+The following properies are added as part of signing, and are optional:
+
+timestamp
+    Time when image was signed (standard Unix time_t format)
+
+signer-name
+    Name of the signer (e.g. "mkimage")
+
+signer-version
+    Version string of the signer (e.g. "2013.01")
+
+comment
+    Additional information about the signer or image
+
+padding
+    The padding algorithm, it may be pkcs-1.5 or pss,
+    if no value is provided we assume pkcs-1.5
+
+
+
+Examples
+--------
+
+Some example files are available here, showing various scenarios
+
+.. toctree::
+    :maxdepth: 1
+
+    kernel
+    kernel_fdt
+    kernel_fdts_compressed
+    multi
+    multi_spl
+    multi-with-fpga
+    multi-with-loadables
+    sec_firmware_ppa
+    sign-configs
+    sign-images
+    uefi
+    update3
+    update_uboot
+
+.. sectionauthor:: Marian Balakowicz <[email protected]>
+.. sectionauthor:: External data additions, 25/1/16 Simon Glass <[email protected]>
diff --git a/doc/usage/fit/uefi.rst b/doc/usage/fit/uefi.rst
new file mode 100644
index 00000000000..3bbacb5cad0
--- /dev/null
+++ b/doc/usage/fit/uefi.rst
@@ -0,0 +1,72 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+UEFI
+====
+
+Example FIT image description file demonstrating the usage of the
+bootm command to launch UEFI binaries.
+
+Two boot configurations are available to enable booting GRUB2 on QEMU,
+the former uses a FDT blob contained in the FIT image, while the later
+relies on the FDT provided by the board emulator.
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "GRUB2 EFI and QEMU FDT blob";
+        #address-cells = <1>;
+
+        images {
+            efi-grub {
+                description = "GRUB EFI Firmware";
+                data = /incbin/("bootarm.efi");
+                type = "kernel_noload";
+                arch = "arm";
+                os = "efi";
+                compression = "none";
+                load = <0x0>;
+                entry = <0x0>;
+                hash-1 {
+                    algo = "sha256";
+                };
+            };
+
+            fdt-qemu {
+                description = "QEMU DTB";
+                data = /incbin/("qemu-arm.dtb");
+                type = "flat_dt";
+                arch = "arm";
+                compression = "none";
+                hash-1 {
+                    algo = "sha256";
+                };
+            };
+        };
+
+        configurations {
+            default = "config-grub-fdt";
+
+            config-grub-fdt {
+                description = "GRUB EFI Boot w/ FDT";
+                kernel = "efi-grub";
+                fdt = "fdt-qemu";
+                signature-1 {
+                    algo = "sha256,rsa2048";
+                    key-name-hint = "dev";
+                    sign-images = "kernel", "fdt";
+                };
+            };
+
+            config-grub-nofdt {
+                description = "GRUB EFI Boot w/o FDT";
+                kernel = "efi-grub";
+                signature-1 {
+                    algo = "sha256,rsa2048";
+                    key-name-hint = "dev";
+                    sign-images = "kernel";
+                };
+            };
+        };
+    };
diff --git a/doc/usage/fit/update3.rst b/doc/usage/fit/update3.rst
new file mode 100644
index 00000000000..4ff3950c01e
--- /dev/null
+++ b/doc/usage/fit/update3.rst
@@ -0,0 +1,47 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Automatic software update: multiple files
+=========================================
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "Automatic software updates: kernel, ramdisk, FDT";
+        #address-cells = <1>;
+
+        images {
+            update-1 {
+                description = "Linux kernel binary";
+                data = /incbin/("./vmlinux.bin.gz");
+                compression = "none";
+                type = "firmware";
+                load = <FF700000>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+            update-2 {
+                description = "Ramdisk image";
+                data = /incbin/("./ramdisk_image.gz");
+                compression = "none";
+                type = "firmware";
+                load = <FF8E0000>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+
+            update-3 {
+                description = "FDT blob";
+                data = /incbin/("./blob.fdt");
+                compression = "none";
+                type = "firmware";
+                load = <FFAC0000>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+        };
+    };
diff --git a/doc/usage/fit/update_uboot.rst b/doc/usage/fit/update_uboot.rst
new file mode 100644
index 00000000000..a9288ee6367
--- /dev/null
+++ b/doc/usage/fit/update_uboot.rst
@@ -0,0 +1,28 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Automatic software update
+=========================
+
+Make sure the flashing addresses ('load' prop) is correct for your board!
+
+::
+
+    /dts-v1/;
+
+    / {
+        description = "Automatic U-Boot update";
+        #address-cells = <1>;
+
+        images {
+            update-1 {
+                description = "U-Boot binary";
+                data = /incbin/("./u-boot.bin");
+                compression = "none";
+                type = "firmware";
+                load = <0xFFFC0000>;
+                hash-1 {
+                    algo = "sha1";
+                };
+            };
+        };
+    };
diff --git a/doc/usage/fit/verified-boot.rst b/doc/usage/fit/verified-boot.rst
new file mode 100644
index 00000000000..301207711db
--- /dev/null
+++ b/doc/usage/fit/verified-boot.rst
@@ -0,0 +1,107 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+U-Boot Verified Boot
+====================
+
+Introduction
+------------
+
+Verified boot here means the verification of all software loaded into a
+machine during the boot process to ensure that it is authorised and correct
+for that machine.
+
+Verified boot extends from the moment of system reset to as far as you wish
+into the boot process. An example might be loading U-Boot from read-only
+memory, then loading a signed kernel, then using the kernel's dm-verity
+driver to mount a signed root filesystem.
+
+A key point is that it is possible to field-upgrade the software on machines
+which use verified boot. Since the machine will only run software that has
+been correctly signed, it is safe to read software from an updatable medium.
+It is also possible to add a secondary signed firmware image, in read-write
+memory, so that firmware can easily be upgraded in a secure manner.
+
+
+Signing
+-------
+
+Verified boot uses cryptographic algorithms to 'sign' software images.
+Images are signed using a private key known only to the signer, but can
+be verified using a public key. As its name suggests the public key can be
+made available without risk to the verification process. The private and
+public keys are mathematically related. For more information on how this
+works look up "public key cryptography" and "RSA" (a particular algorithm).
+
+The signing and verification process looks something like this::
+
+
+          Signing                                      Verification
+          =======                                      ============
+
+      +--------------+                 *
+      | RSA key pair |                 *             +---------------+
+      | .key  .crt   |                 *             | Public key in |
+      +--------------+     +------> public key ----->| trusted place |
+            |              |           *             +---------------+
+            |              |           *                    |
+            v              |           *                    v
+       +---------+         |           *             +--------------+
+       |         |---------+           *             |              |
+       | signer  |                     *             |    U-Boot    |
+       |         |---------+           *             |  signature   |--> yes/no
+       +---------+         |           *             | verification |
+            ^              |           *             |              |
+            |              |           *             +--------------+
+            |              |           *                    ^
+       +----------+        |           *                    |
+       | Software |        +----> signed image -------------+
+       |  image   |                    *
+       +----------+                    *
+
+
+The signature algorithm relies only on the public key to do its work. Using
+this key it checks the signature that it finds in the image. If it verifies
+then we know that the image is OK.
+
+The public key from the signer allows us to verify and therefore trust
+software from updatable memory.
+
+It is critical that the public key be secure and cannot be tampered with.
+It can be stored in read-only memory, or perhaps protected by other on-chip
+crypto provided by some modern SOCs. If the public key can be changed, then
+the verification is worthless.
+
+
+Chaining Images
+---------------
+
+The above method works for a signer providing images to a run-time U-Boot.
+It is also possible to extend this scheme to a second level, like this:
+
+#. Master private key is used by the signer to sign a first-stage image.
+#. Master public key is placed in read-only memory.
+#. Secondary private key is created and used to sign second-stage images.
+#. Secondary public key is placed in first stage images
+#. We use the master public key to verify the first-stage image. We then
+   use the secondary public key in the first-stage image to verify the second-
+   state image.
+#. This chaining process can go on indefinitely. It is recommended to use a
+   different key at each stage, so that a compromise in one place will not
+   affect the whole change.
+
+
+Flattened Image Tree (FIT)
+--------------------------
+
+The FIT format is already widely used in U-Boot. It is a flattened device
+tree (FDT) in a particular format, with images contained within. FITs
+include hashes to verify images, so it is relatively straightforward to
+add signatures as well.
+
+The public key can be stored in U-Boot's CONFIG_OF_CONTROL device tree in
+a standard place. Then when a FIT is loaded it can be verified using that
+public key. Multiple keys and multiple signatures are supported.
+
+See :doc:`signature` for more information.
+
+.. sectionauthor:: Simon Glass <[email protected]> 1-1-13
diff --git a/doc/usage/fit/x86-fit-boot.rst b/doc/usage/fit/x86-fit-boot.rst
new file mode 100644
index 00000000000..93b73bb9019
--- /dev/null
+++ b/doc/usage/fit/x86-fit-boot.rst
@@ -0,0 +1,269 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Booting Linux on x86 with FIT
+=============================
+
+Background
+----------
+
+Generally Linux x86 uses its own very complex booting method. There is a setup
+binary which contains all sorts of parameters and a compressed self-extracting
+binary for the kernel itself, often with a small built-in serial driver to
+display decompression progress.
+
+The x86 CPU has various processor modes. I am no expert on these, but my
+understanding is that an x86 CPU (even a really new one) starts up in a 16-bit
+'real' mode where only 1MB of memory is visible, moves to 32-bit 'protected'
+mode where 4GB is visible (or more with special memory access techniques) and
+then to 64-bit 'long' mode if 64-bit execution is required.
+
+Partly the self-extracting nature of Linux was introduced to cope with boot
+loaders that were barely capable of loading anything. Even changing to 32-bit
+mode was something of a challenge, so putting this logic in the kernel seemed
+to make sense.
+
+Bit by bit more and more logic has been added to this post-boot pre-Linux
+wrapper:
+
+- Changing to 32-bit mode
+- Decompression
+- Serial output (with drivers for various chips)
+- Load address randomisation
+- Elf loader complete with relocation (for the above)
+- Random number generator via 3 methods (again for the above)
+- Some sort of EFI mini-loader (1000+ glorious lines of code)
+- Locating and tacking on a device tree and ramdisk
+
+To my mind, if you sit back and look at things from first principles, this
+doesn't make a huge amount of sense. Any boot loader worth its salts already
+has most of the above features and more besides. The boot loader already knows
+the layout of memory, has a serial driver, can decompress things, includes an
+ELF loader and supports device tree and ramdisks. The decision to duplicate
+all these features in a Linux wrapper caters for the lowest common
+denominator: a boot loader which consists of a BIOS call to load something off
+disk, followed by a jmp instruction.
+
+(Aside: On ARM systems, we worry that the boot loader won't know where to load
+the kernel. It might be easier to just provide that information in the image,
+or in the boot loader rather than adding a self-relocator to put it in the
+right place. Or just use ELF?
+
+As a result, the x86 kernel boot process is needlessly complex. The file
+format is also complex, and obfuscates the contents to a degree that it is
+quite a challenge to extract anything from it. This bzImage format has become
+so prevalent that is actually isn't possible to produce the 'raw' kernel build
+outputs with the standard Makefile (as it is on ARM for example, at least at
+the time of writing).
+
+This document describes an alternative boot process which uses simple raw
+images which are loaded into the right place by the boot loader and then
+executed.
+
+
+Build the kernel
+----------------
+
+Note: these instructions assume a 32-bit kernel. U-Boot also supports directly
+booting a 64-bit kernel by jumping into 64-bit mode first (see below).
+
+You can build the kernel as normal with 'make'. This will create a file called
+'vmlinux'. This is a standard ELF file and you can look at it if you like::
+
+    $ objdump -h vmlinux
+
+    vmlinux:     file format elf32-i386
+
+    Sections:
+    Idx Name          Size      VMA       LMA       File off  Algn
+      0 .text         00416850  81000000  01000000  00001000  2**5
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
+      1 .notes        00000024  81416850  01416850  00417850  2**2
+                      CONTENTS, ALLOC, LOAD, READONLY, CODE
+      2 __ex_table    00000c50  81416880  01416880  00417880  2**3
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+      3 .rodata       00154b9e  81418000  01418000  00419000  2**5
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+      4 __bug_table   0000597c  8156cba0  0156cba0  0056dba0  2**0
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+      5 .pci_fixup    00001b80  8157251c  0157251c  0057351c  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+      6 .tracedata    00000024  8157409c  0157409c  0057509c  2**0
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+      7 __ksymtab     00007ec0  815740c0  015740c0  005750c0  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+      8 __ksymtab_gpl 00004a28  8157bf80  0157bf80  0057cf80  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+      9 __ksymtab_strings 0001d6fc  815809a8  015809a8  005819a8  2**0
+                      CONTENTS, ALLOC, LOAD, READONLY, DATA
+     10 __init_rodata 00001c3c  8159e0a4  0159e0a4  0059f0a4  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+     11 __param       00000ff0  8159fce0  0159fce0  005a0ce0  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+     12 __modver      00000330  815a0cd0  015a0cd0  005a1cd0  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+     13 .data         00063000  815a1000  015a1000  005a2000  2**12
+                      CONTENTS, ALLOC, LOAD, RELOC, DATA
+     14 .init.text    0002f104  81604000  01604000  00605000  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
+     15 .init.data    00040cdc  81634000  01634000  00635000  2**12
+                      CONTENTS, ALLOC, LOAD, RELOC, DATA
+     16 .x86_cpu_dev.init 0000001c  81674cdc  01674cdc  00675cdc  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+     17 .altinstructions 0000267c  81674cf8  01674cf8  00675cf8  2**0
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+     18 .altinstr_replacement 00000942  81677374  01677374  00678374  2**0
+                      CONTENTS, ALLOC, LOAD, READONLY, CODE
+     19 .iommu_table  00000014  81677cb8  01677cb8  00678cb8  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+     20 .apicdrivers  00000004  81677cd0  01677cd0  00678cd0  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, DATA
+     21 .exit.text    00001a80  81677cd8  01677cd8  00678cd8  2**0
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
+     22 .data..percpu 00007880  8167a000  0167a000  0067b000  2**12
+                      CONTENTS, ALLOC, LOAD, RELOC, DATA
+     23 .smp_locks    00003000  81682000  01682000  00683000  2**2
+                      CONTENTS, ALLOC, LOAD, RELOC, READONLY, DATA
+     24 .bss          000a1000  81685000  01685000  00686000  2**12
+                      ALLOC
+     25 .brk          00424000  81726000  01726000  00686000  2**0
+                      ALLOC
+     26 .comment      00000049  00000000  00000000  00686000  2**0
+                      CONTENTS, READONLY
+     27 .GCC.command.line 0003e055  00000000  00000000  00686049  2**0
+                      CONTENTS, READONLY
+     28 .debug_aranges 0000f4c8  00000000  00000000  006c40a0  2**3
+                      CONTENTS, RELOC, READONLY, DEBUGGING
+     29 .debug_info   0440b0df  00000000  00000000  006d3568  2**0
+                      CONTENTS, RELOC, READONLY, DEBUGGING
+     30 .debug_abbrev 0022a83b  00000000  00000000  04ade647  2**0
+                      CONTENTS, READONLY, DEBUGGING
+     31 .debug_line   004ead0d  00000000  00000000  04d08e82  2**0
+                      CONTENTS, RELOC, READONLY, DEBUGGING
+     32 .debug_frame  0010a960  00000000  00000000  051f3b90  2**2
+                      CONTENTS, RELOC, READONLY, DEBUGGING
+     33 .debug_str    001b442d  00000000  00000000  052fe4f0  2**0
+                      CONTENTS, READONLY, DEBUGGING
+     34 .debug_loc    007c7fa9  00000000  00000000  054b291d  2**0
+                      CONTENTS, RELOC, READONLY, DEBUGGING
+     35 .debug_ranges 00098828  00000000  00000000  05c7a8c8  2**3
+                      CONTENTS, RELOC, READONLY, DEBUGGING
+
+There is also the setup binary mentioned earlier. This is at
+arch/x86/boot/setup.bin and is about 12KB in size. It includes the command
+line and various settings need by the kernel. Arguably the boot loader should
+provide all of this also, but setting it up is some complex that the kernel
+helps by providing a head start.
+
+As you can see the code loads to address 0x01000000 and everything else
+follows after that. We could load this image using the 'bootelf' command but
+we would still need to provide the setup binary. This is not supported by
+U-Boot although I suppose you could mostly script it. This would permit the
+use of a relocatable kernel.
+
+All we need to boot is the vmlinux file and the setup.bin file.
+
+
+Create a FIT
+------------
+
+To create a FIT you will need a source file describing what should go in the
+FIT. See kernel.its for an example for x86 and also instructions on setting
+the 'arch' value for booting 64-bit kernels if desired. Put this into a file
+called image.its.
+
+Note that setup is loaded to the special address of 0x90000 (a special address
+you just have to know) and the kernel is loaded to 0x01000000 (the address you
+saw above). This means that you will need to load your FIT to a different
+address so that U-Boot doesn't overwrite it when decompressing. Something like
+0x02000000 will do so you can set CONFIG_SYS_LOAD_ADDR to that.
+
+In that example the kernel is compressed with lzo. Also we need to provide a
+flat binary, not an ELF. So the steps needed to set things are are::
+
+    # Create a flat binary
+    objcopy -O binary vmlinux vmlinux.bin
+
+    # Compress it into LZO format
+    lzop vmlinux.bin
+
+    # Build a FIT image
+    mkimage -f image.its image.fit
+
+(be careful to run the mkimage from your U-Boot tools directory since it
+will have x86_setup support.)
+
+You can take a look at the resulting fit file if you like::
+
+    $ dumpimage -l image.fit
+    FIT description: Simple image with single Linux kernel on x86
+    Created:         Tue Oct  7 10:57:24 2014
+     Image 0 (kernel)
+      Description:  Vanilla Linux kernel
+      Created:      Tue Oct  7 10:57:24 2014
+      Type:         Kernel Image
+      Compression:  lzo compressed
+      Data Size:    4591767 Bytes = 4484.15 kB = 4.38 MB
+      Architecture: Intel x86
+      OS:           Linux
+      Load Address: 0x01000000
+      Entry Point:  0x00000000
+      Hash algo:    sha1
+      Hash value:   446b5163ebfe0fb6ee20cbb7a8501b263cd92392
+     Image 1 (setup)
+      Description:  Linux setup.bin
+      Created:      Tue Oct  7 10:57:24 2014
+      Type:         x86 setup.bin
+      Compression:  uncompressed
+      Data Size:    12912 Bytes = 12.61 kB = 0.01 MB
+      Hash algo:    sha1
+      Hash value:   a1f2099cf47ff9816236cd534c77af86e713faad
+     Default Configuration: 'config-1'
+     Configuration 0 (config-1)
+      Description:  Boot Linux kernel
+      Kernel:       kernel
+
+
+Booting the FIT
+---------------
+
+To make it boot you need to load it and then use 'bootm' to boot it. A
+suitable script to do this from a network server is::
+
+    bootp
+    tftp image.fit
+    bootm
+
+This will load the image from the network and boot it. The command line (from
+the 'bootargs' environment variable) will be passed to the kernel.
+
+If you want a ramdisk you can add it as normal with FIT. If you want a device
+tree then x86 doesn't normally use those - it has ACPI instead.
+
+
+Why Bother?
+-----------
+
+#. It demystifies the process of booting an x86 kernel
+#. It allows use of the standard U-Boot boot file format
+#. It allows U-Boot to perform decompression - problems will provide an error
+   message and you are still in the boot loader. It is possible to investigate.
+#. It avoids all the pre-loader code in the kernel which is quite complex to
+   follow
+#. You can use verified/secure boot and other features which haven't yet been
+   added to the pre-Linux
+#. It makes x86 more like other architectures in the way it boots a kernel.
+   You can potentially use the same file format for the kernel, and the same
+   procedure for building and packaging it.
+
+
+References
+----------
+
+In the Linux kernel, Documentation/x86/boot.txt defines the boot protocol for
+the kernel including the setup.bin format. This is handled in U-Boot in
+arch/x86/lib/zimage.c and arch/x86/lib/bootm.c.
+
+Various files in the same directory as this file describe the FIT format.
+
+
+.. sectionauthor:: Simon Glass <[email protected]> 7-Oct-2014
diff --git a/doc/usage/index.rst b/doc/usage/index.rst
index 84ef8a9a427..388e59f1733 100644
--- a/doc/usage/index.rst
+++ b/doc/usage/index.rst
@@ -8,7 +8,7 @@ Use U-Boot
    dfu
    environment
    fdt_overlays
-   fit
+   fit/index
    netconsole
    partitions
    cmdline
@@ -25,12 +25,14 @@ Shell commands
    cmd/askenv
    cmd/base
    cmd/bdinfo
+   cmd/bind
    cmd/blkcache
    cmd/bootd
    cmd/bootdev
    cmd/bootefi
    cmd/bootflow
    cmd/booti
+   cmd/bootm
    cmd/bootmenu
    cmd/bootmeth
    cmd/button
@@ -62,9 +64,11 @@ Shell commands
    cmd/fwu_mdata
    cmd/gpio
    cmd/host
+   cmd/imxtract
    cmd/load
    cmd/loadb
    cmd/loadm
+   cmd/loads
    cmd/loadx
    cmd/loady
    cmd/mbr
@@ -81,6 +85,7 @@ Shell commands
    cmd/read
    cmd/reset
    cmd/rng
+   cmd/saves
    cmd/sbi
    cmd/sf
    cmd/scp03
@@ -96,6 +101,7 @@ Shell commands
    cmd/trace
    cmd/true
    cmd/ums
+   cmd/unbind
    cmd/ut
    cmd/wdt
    cmd/wget