[PATCH v3 7/7] rockchip: doc: add rkmtd.rst

[Johan Jonker <jbx6244@gmail.com>]

Add documention for Rockchip rkmtd virtual block device.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
---

Changed V3:
  New patch
---
 doc/board/rockchip/index.rst |   1 +
 doc/board/rockchip/rkmtd.rst | 105 +++++++++++++++++++++++++++++++++++
 2 files changed, 106 insertions(+)
 create mode 100644 doc/board/rockchip/rkmtd.rst

diff --git a/doc/board/rockchip/index.rst b/doc/board/rockchip/index.rst
index 0c377e9bbba0..9a87a035e95e 100644
--- a/doc/board/rockchip/index.rst
+++ b/doc/board/rockchip/index.rst
@@ -8,3 +8,4 @@ Rockchip
    :maxdepth: 2

    rockchip
+   rkmtd
diff --git a/doc/board/rockchip/rkmtd.rst b/doc/board/rockchip/rkmtd.rst
new file mode 100644
index 000000000000..1481380ba6c5
--- /dev/null
+++ b/doc/board/rockchip/rkmtd.rst
@@ -0,0 +1,105 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. Copyright (C) 2023 Johan Jonker <jbx6244@gmail.com>
+
+RKMTD
+=====
+
+Info
+----
+
+The command rkmtd creates a virtual block device to transfer
+Rockchip boot block data to and from NAND with block orientated
+tools like "ums" and "rockusb".
+
+It uses the Rockchip MTD driver to scan for boot blocks and copies
+data from the first block in a GPT formatted virtual disk.
+Data must be written in U-boot "idbloader.img" format and start at
+partition "loader1" offset 64. The data header is parsed
+for length and offset. When the last sector is received
+it erases up to 5 erase blocks on NAND and writes boot blocks
+in a pattern depending on the NAND ID. Data is then verified.
+When a block turns out bad the block header is discarded.
+
+Limitations
+-----------
+
+- Support with CONFIG_ROCKCHIP_NAND MTD driver only.
+- Support for Rockchip boot block header type 1 only.
+- Pattern for listed NAND IDs only. (Logic still not disclosed by Rockchip)
+- The MTD framework driver data and NAND ID must be extracted at a lower level.
+
+Available rkmtd commands
+------------------------
+
+.. code-block:: bash
+
+        rkmtd bind <label>      - bind RKMTD device
+        rkmtd unbind <label>    - unbind RKMTD device
+        rkmtd info [<label>]    - show all available RKMTD devices
+        rkmtd dev [<label>]     - show or set current RKMTD device
+
+U-boot settings
+---------------
+
+Config to enable Rockchip MTD support:
+
+.. code-block:: bash
+
+        CONFIG_MTD=y
+        CONFIG_MTD_RAW_NAND=y
+        CONFIG_SYS_NAND_DRIVER_ECC_LAYOUT=y
+        CONFIG_SYS_NAND_USE_FLASH_BBT=y
+        CONFIG_ROCKCHIP_NAND=y
+
+Option to keep existing NAND data unchanged:
+
+.. code-block:: bash
+
+        CONFIG_ROCKCHIP_NAND_SKIP_BBTSCAN=y
+
+Commands to enable:
+
+.. code-block:: bash
+
+        CONFIG_CMD_USB=y
+        CONFIG_CMD_RKMTD=y
+        CONFIG_CMD_ROCKUSB=y
+        CONFIG_CMD_USB_MASS_STORAGE=y
+
+Linux Host (PC) tool commands combinations that work
+----------------------------------------------------
+
+.. table::
+   :widths: 20 44
+
+   ==================== ============================================
+   U-boot               Linux
+   ==================== ============================================
+   rkmtd bind 0
+   rockusb 0 rkmtd 0
+                        upgrade_tool pl
+
+                        upgrade_tool rl 64 512 idbloader_backup.img
+
+                        upgrade_tool wl 64 idbloader.img
+
+                        upgrade_tool rd
+
+                        rkdeveloptool ppt
+
+                        rkdeveloptool rl 64 512 idbloader_backup.img
+
+                        rkdeveloptool wlx loader1 idbloader.img
+
+                        rkdeveloptool wl 64 idbloader.img
+
+                        rkdeveloptool rd
+
+                        rkflashtool r 64 512 > idbloader_backup.img
+
+                        rkflashtool w 64 512 < idbloader.img
+   ums 0 rkmtd 0
+                        dd if=/dev/sda1 of=idbloader_backup.img
+
+                        dd if=idbloader.img of=/dev/sda1
+   ==================== ============================================
--
2.39.2