Documentation for plugin-manager / EEPROM -- Source code for cboot / nvtboot?

I am working on building a modular system with Jetson TX2 where you can exchange different camera modules connected to the CSI port (after power-down, of course). My implementation will be based on how the OV5693 camera EEPROM (included with TX2 Dev Kit) interact with the plugin-manager and bootloader (cboot) to overlay the required device-tree nodes.

I can see from the cboot log that it reads the module EEPROM (24C02) that is connected to camera’s I2C bus addressed 0x54. I extracted its content using i2cdump and found that it uses the same EEPROM format as documented in (see below)

I assume that the cboot reads a string related to the part number and creates a device-tree node, then plugin-manager takes that node and match it with a pre-configured matching pattern. In this case it’s "ids = “3326-*” found on tegra186-quill-camera-plugin-manager.dtsi.

I would like to implement a similar scheme for my custom-made camera board with an EEPROM. However, this whole process is not well documented. I am also not sure whether I had the correct assumption, so I want to make sure I fully understand the plugin-manager before going any further. What I essentially need is either

  • source code for cboot / nvtboot
  • documentation of the plugin-manager

For the source code, I tried to locate it on, but only found U-boot.


[0001.174] I> Welcome to Cboot
[0001.846] I> Find /i2c@3180000’s alias i2c2
[0001.850] I> Reading eeprom i2c=2 address=0x54
[0001.854] I> Enablindtb (bin_type 1)
[0003.373] I> Kernel DTB @ 0x92000000
[0003.504] I> Updated bootarg info to DTB
[0003.508] E> "plugin-manager" doesn’t exist, creating
[0003.582] I> create_pm_ids: id: 3326-1000-100-M, len: 15
[0003.622] E> "module@0x57" doesn’t exist, creating
[0003.627] I> Adding plugin-manager/ids/3326-1000-100=/i2c@3180000:module0x70000000] to /memory
U-Boot 2016.07-g9c3b9a4 (Mar 01 2018 - 20:41:10 -0800)
Starting kernel ...
[    0.138901] Initializing plugin-manager
[    0.138953] Plugin module not found
[    0.146099] node /plugin-manager/fragment-e3326@0 match with board 3326-*

OV5693 camera’s EEPROM from TX2 Dev Kit

Name			Value			Start	Size	Comment
uint16 version		1			0h	2h	Board ID, EEPROM format version.
uint16 size		7			2h	2h	Length of board ID data; no longer supported.
uint16 board_no		3326			4h	2h	board ID
uint16 sku		1000			6h	2h	1000 is the Jetson TX1/TX2 SKU
ubyte fab		1			8h	1h	
char rev		77 'M'			9h	1h	single capital letter, the manufacturing major revision
char minor_rev		0			Ah	1h	single decimal digit, the manufacturing minor revision
ubyte mem_type		255			Bh	1h	
ubyte pwr_cfg		255			Ch	1h	
ubyte misc_cfg		255			Dh	1h	
ubyte modem_cfg		255			Eh	1h	
ubyte touch_cfg		255			Fh	1h	
ubyte disp_cfg		255			10h	1h	
ubyte rework_lvl	0			11h	1h	
uint16 sno		6691			12h	2h	serial no.?
char assetf1[30]	699-83326-1000-100 M.0	14h	1Eh	Product Part Number*, used for asset tracking.
ubyte wifi_mac[6]	FF:FF:FF:FF:FF:FF	32h	6h	Factory default Wi-Fi MAC address.
ubyte bt_mac[6]		FF:FF:FF:FF:FF:FF	38h	6h	Factory default BT MAC address.
ubyte second_wifi_mac[6]FF:FF:FF:FF:FF:FF	3Eh	6h	Secondary Wi-Fi MAC address.
ubyte eth_mac[6]	FF:FF:FF:FF:FF:FF	44h	6h	Factory default Gigabit Ethernet MAC address.
char assetf2[15]	0325017206691		4Ah	Fh	Asset tracking number, a unique string corresponding to the number on the device’s identifying sticker. A character string padded with 0x00 or 0xFF characters.
ubyte reserved[61]				59h	3Dh	Reserved for future use.
char cust_block_sig[4]	"FFFF"			96h	4h	Block signature; stands for "NVIDIA Configuration Block."
uint16 cust_block_len	65535			9Ah	2h	Length of this struct from block signature to end. Value is subject to change.
char cust_type_sig[2]	"FF"			9Ch	2h	Format of following MAC address data: "MAC address, field format version 1."
uint16 cust_ver	65535				9Eh	2h	Version.
ubyte cust_wifi_mac[6]	FF:FF:FF:FF:FF:FF	A0h	6h	Vendor-specified Wi-Fi MAC address.
ubyte cust_bt_mac[6]	FF:FF:FF:FF:FF:FF	A6h	6h	Vendor-specified Wi-Fi MAC address.
ubyte cust_eth_mac[6]	FF:FF:FF:FF:FF:FF	ACh	6h	Vendor-specified Gigabit Ethernet MAC address. Last field in the struct whose length is in bytes 154-155.
ubyte cust_reserved[77]				B2h	4Dh	Reserved for future use.
ubyte checksum		17h			FFh	1h	CRC-8 computed for bytes 0-254.


Sorry that we lack of this document. We will try to improve it.
You could refer to the source code of plugin-manager as a start. It is in our publilc kernel driver-> “kernel/kernel-4.4/drivers/of/plugin-manager.c”

Hi piyamate, Please see if is enough. Thanks!

I can see that the cboot source code is now publicly avilable. It was released on yesterday together with the new JetPack 28.2.1.

Thanks to @WayneWWW and @vickyy I think I have most of the information I need.
The device-tree file editing is still an unknown becuase there is no documentation, but I can start trying something now that I have the source code of everything.