doc/README.usb - platform/external/u-boot - Gitiles

 SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2001
  * Denis Peter, MPL AG Switzerland
  */

 USB Support
 ===========

 The USB support is implemented on the base of the UHCI Host
 controller.

 Currently supported are USB Hubs, USB Keyboards, USB Floppys, USB
 flash sticks and USB network adaptors.
 Tested with a TEAC Floppy TEAC FD-05PUB and Chicony KU-8933 Keyboard.

 How it works:
 -------------

 The USB (at least the USB UHCI) needs a frame list (4k), transfer
 descriptor and queue headers which are all located in the main memory.
 The UHCI allocates every millisecond the PCI bus and reads the current
 frame pointer. This may cause to crash the OS during boot. So the USB
 _MUST_ be stopped during OS boot. This is the reason, why the USB is
 NOT automatically started during start-up. If someone needs the USB
 he has to start it and should therefore be aware that he had to stop
 it before booting the OS.

 For USB keyboards this can be done by a script which is automatically
 started after the U-Boot is up and running. To boot an OS with a
 USB keyboard another script is necessary, which first disables the
 USB and then executes the boot command. If the boot command fails,
 the script can re-enable the USB keyboard.

 Common USB Commands:
 - usb start:
 - usb reset:	    (re)starts the USB. All USB devices will be
 		    initialized and a device tree is build for them.
 - usb tree:	    shows all USB devices in a tree like display
 - usb info [dev]:   shows all USB infos of the device dev, or of all
 		    the devices
 - usb stop [f]:	    stops the USB. If f==1 the USB will also stop if
 		    a USB keyboard is assigned as stdin. The stdin
 		    is then switched to serial input.
 Storage USB Commands:
 - usb scan:	    scans the USB for storage devices. The USB must be
 		    running for this command (usb start)
 - usb device [dev]: show or set current USB storage device
 - usb part [dev]:   print partition table of one or all USB storage
 		    devices
 - usb read addr blk# cnt:
 		    read `cnt' blocks starting at block `blk#'to
 		    memory address `addr'
 - usbboot addr dev:part:
 		    boot from USB device

 Config Switches:
 ----------------
 CONFIG_CMD_USB	    enables basic USB support and the usb command
 CONFIG_USB_UHCI	    defines the lowlevel part. A lowlevel part must be defined
 		    if using CONFIG_CMD_USB
 CONFIG_USB_KEYBOARD enables the USB Keyboard
 CONFIG_USB_STORAGE  enables the USB storage devices
 CONFIG_USB_HOST_ETHER	enables USB ethernet adapter support


 USB Host Networking
 ===================

 If you have a supported USB Ethernet adapter you can use it in U-Boot
 to obtain an IP address and load a kernel from a network server.

 Note: USB Host Networking is not the same as making your board act as a USB
 client. In that case your board is pretending to be an Ethernet adapter
 and will appear as a network interface to an attached computer. In that
 case the connection is via a USB cable with the computer acting as the host.

 With USB Host Networking, your board is the USB host. It controls the
 Ethernet adapter to which it is directly connected and the connection to
 the outside world is your adapter's Ethernet cable. Your board becomes an
 independent network device, able to connect and perform network operations
 independently of your computer.


 Device support
 --------------

 Currently supported devices are listed in the drivers according to
 their vendor and product IDs. You can check your device by connecting it
 to a Linux machine and typing 'lsusb'. The drivers are in
 drivers/usb/eth.

 For example this lsusb output line shows a device with Vendor ID 0x0x95
 and product ID 0x7720:

 Bus 002 Device 010: ID 0b95:7720 ASIX Electronics Corp. AX88772

 If you look at drivers/usb/eth/asix.c you will see this line within the
 supported device list, so we know this adapter is supported.

 	{ 0x0b95, 0x7720 },	/* Trendnet TU2-ET100 V3.0R */

 If your adapter is not listed there is a still a chance that it will
 work. Try looking up the manufacturer of the chip inside your adapter.
 or take the adapter apart and look for chip markings. Then add a line
 for your vendor/product ID into the table of the appropriate driver,
 build U-Boot and see if it works. If not then there might be differences
 between the chip in your adapter and the driver. You could try to get a
 datasheet for your device and add support for it to U-Boot. This is not
 particularly difficult - you only need to provide support for four basic
 functions: init, halt, send and recv.


 Enabling USB Host Networking
 ----------------------------

 The normal U-Boot commands are used with USB networking, but you must
 start USB first. For example:

 usb start
 setenv bootfile /tftpboot/uImage
 bootp


 To enable USB Host Ethernet in U-Boot, your platform must of course
 support USB with CONFIG_CMD_USB enabled and working. You will need to
 add some settings to your board configuration:

 CONFIG_CMD_USB=y		/* the 'usb' interactive command */
 CONFIG_USB_HOST_ETHER=y		/* Enable USB Ethernet adapters */

 and one or more of the following for individual adapter hardware:

 CONFIG_USB_ETHER_ASIX=y
 CONFIG_USB_ETHER_ASIX88179=y
 CONFIG_USB_ETHER_LAN75XX=y
 CONFIG_USB_ETHER_LAN78XX=y
 CONFIG_USB_ETHER_MCS7830=y
 CONFIG_USB_ETHER_RTL8152=y
 CONFIG_USB_ETHER_SMSC95XX=y

 As with built-in networking, you will also want to enable some network
 commands, for example:

 CONFIG_CMD_NET=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_DHCP=y

 and some bootp options, which tell your board to obtain its subnet,
 gateway IP, host name and boot path from the bootp/dhcp server. These
 settings should start you off:

 #define CONFIG_BOOTP_SUBNETMASK
 #define CONFIG_BOOTP_GATEWAY
 #define CONFIG_BOOTP_HOSTNAME
 #define CONFIG_BOOTP_BOOTPATH

 You can also set the default IP address of your board and the server
 as well as the default file to load when a 'bootp' command is issued.
 However note that encoding these individual network settings into a
 common executable is discouraged, as it leads to potential conflicts,
 and all the parameters can either get stored in the board's external
 environment, or get obtained from the bootp server if not set.

 #define CONFIG_IPADDR		10.0.0.2  (replace with your value)
 #define CONFIG_SERVERIP		10.0.0.1  (replace with your value)
 #define CONFIG_BOOTFILE		"uImage"

 The 'usb start' command should identify the adapter something like this:

 CrOS> usb start
 (Re)start USB...
 USB EHCI 1.00
 scanning bus for devices... 3 USB Device(s) found
        scanning bus for storage devices... 0 Storage Device(s) found
        scanning bus for ethernet devices... 1 Ethernet Device(s) found
 CrOS> print ethact
 ethact=asx0

 You can see that it found an ethernet device and we can print out the
 device name (asx0 in this case).

 Then 'bootp' or 'dhcp' should use it to obtain an IP address from DHCP,
 perhaps something like this:

 CrOS> bootp
 Waiting for Ethernet connection... done.
 BOOTP broadcast 1
 BOOTP broadcast 2
 DHCP client bound to address 172.22.73.81
 Using asx0 device
 TFTP from server 172.22.72.144; our IP address is 172.22.73.81
 Filename '/tftpboot/uImage-sjg-seaboard-261347'.
 Load address: 0x40c000
 Loading: #################################################################
 	 #################################################################
 	 #################################################################
 	 ################################################
 done
 Bytes transferred = 3557464 (364858 hex)
 CrOS>


 Another way of doing this is to issue a tftp command, which will cause the
 bootp to happen automatically.


 MAC Addresses
 -------------

 Most Ethernet dongles have a built-in MAC address which is unique in the
 world. This is important so that devices on the network can be
 distinguished from each other. MAC address conflicts are evil and
 generally result in strange and erratic behaviour.

 Some boards have USB Ethernet chips on-board, and these sometimes do not
 have an assigned MAC address. In this case it is up to you to assign
 one which is unique. You should obtain a valid MAC address from a range
 assigned to you before you ship the product.

 Built-in Ethernet adapters support setting the MAC address by means of
 an ethaddr environment variable for each interface (ethaddr, eth1addr,
 eth2addr). There is similar support on the USB network side, using the
 names usbethaddr, usbeth1addr, etc. They are kept separate since we
 don't want a USB device taking the MAC address of a built-in device or
 vice versa.

 So if your USB Ethernet chip doesn't have a MAC address available then
 you must set usbethaddr to a suitable MAC address. At the time of
 writing this functionality is only supported by the SMSC driver.
	SPDX-License-Identifier: GPL-2.0+
	/*
	* (C) Copyright 2001
	* Denis Peter, MPL AG Switzerland
	*/

	USB Support
	===========

	The USB support is implemented on the base of the UHCI Host
	controller.

	Currently supported are USB Hubs, USB Keyboards, USB Floppys, USB
	flash sticks and USB network adaptors.
	Tested with a TEAC Floppy TEAC FD-05PUB and Chicony KU-8933 Keyboard.

	How it works:
	-------------

	The USB (at least the USB UHCI) needs a frame list (4k), transfer
	descriptor and queue headers which are all located in the main memory.
	The UHCI allocates every millisecond the PCI bus and reads the current
	frame pointer. This may cause to crash the OS during boot. So the USB
	_MUST_ be stopped during OS boot. This is the reason, why the USB is
	NOT automatically started during start-up. If someone needs the USB
	he has to start it and should therefore be aware that he had to stop
	it before booting the OS.

	For USB keyboards this can be done by a script which is automatically
	started after the U-Boot is up and running. To boot an OS with a
	USB keyboard another script is necessary, which first disables the
	USB and then executes the boot command. If the boot command fails,
	the script can re-enable the USB keyboard.

	Common USB Commands:
	- usb start:
	- usb reset: (re)starts the USB. All USB devices will be
	initialized and a device tree is build for them.
	- usb tree: shows all USB devices in a tree like display
	- usb info [dev]: shows all USB infos of the device dev, or of all
	the devices
	- usb stop [f]: stops the USB. If f==1 the USB will also stop if
	a USB keyboard is assigned as stdin. The stdin
	is then switched to serial input.
	Storage USB Commands:
	- usb scan: scans the USB for storage devices. The USB must be
	running for this command (usb start)
	- usb device [dev]: show or set current USB storage device
	- usb part [dev]: print partition table of one or all USB storage
	devices
	- usb read addr blk# cnt:
	read `cnt' blocks starting at block `blk#'to
	memory address `addr'
	- usbboot addr dev:part:
	boot from USB device

	Config Switches:
	----------------
	CONFIG_CMD_USB enables basic USB support and the usb command
	CONFIG_USB_UHCI defines the lowlevel part. A lowlevel part must be defined
	if using CONFIG_CMD_USB
	CONFIG_USB_KEYBOARD enables the USB Keyboard
	CONFIG_USB_STORAGE enables the USB storage devices
	CONFIG_USB_HOST_ETHER enables USB ethernet adapter support


	USB Host Networking
	===================

	If you have a supported USB Ethernet adapter you can use it in U-Boot
	to obtain an IP address and load a kernel from a network server.

	Note: USB Host Networking is not the same as making your board act as a USB
	client. In that case your board is pretending to be an Ethernet adapter
	and will appear as a network interface to an attached computer. In that
	case the connection is via a USB cable with the computer acting as the host.

	With USB Host Networking, your board is the USB host. It controls the
	Ethernet adapter to which it is directly connected and the connection to
	the outside world is your adapter's Ethernet cable. Your board becomes an
	independent network device, able to connect and perform network operations
	independently of your computer.


	Device support
	--------------

	Currently supported devices are listed in the drivers according to
	their vendor and product IDs. You can check your device by connecting it
	to a Linux machine and typing 'lsusb'. The drivers are in
	drivers/usb/eth.

	For example this lsusb output line shows a device with Vendor ID 0x0x95
	and product ID 0x7720:

	Bus 002 Device 010: ID 0b95:7720 ASIX Electronics Corp. AX88772

	If you look at drivers/usb/eth/asix.c you will see this line within the
	supported device list, so we know this adapter is supported.

	{ 0x0b95, 0x7720 }, /* Trendnet TU2-ET100 V3.0R */

	If your adapter is not listed there is a still a chance that it will
	work. Try looking up the manufacturer of the chip inside your adapter.
	or take the adapter apart and look for chip markings. Then add a line
	for your vendor/product ID into the table of the appropriate driver,
	build U-Boot and see if it works. If not then there might be differences
	between the chip in your adapter and the driver. You could try to get a
	datasheet for your device and add support for it to U-Boot. This is not
	particularly difficult - you only need to provide support for four basic
	functions: init, halt, send and recv.


	Enabling USB Host Networking
	----------------------------

	The normal U-Boot commands are used with USB networking, but you must
	start USB first. For example:

	usb start
	setenv bootfile /tftpboot/uImage
	bootp


	To enable USB Host Ethernet in U-Boot, your platform must of course
	support USB with CONFIG_CMD_USB enabled and working. You will need to
	add some settings to your board configuration:

	CONFIG_CMD_USB=y /* the 'usb' interactive command */
	CONFIG_USB_HOST_ETHER=y /* Enable USB Ethernet adapters */

	and one or more of the following for individual adapter hardware:

	CONFIG_USB_ETHER_ASIX=y
	CONFIG_USB_ETHER_ASIX88179=y
	CONFIG_USB_ETHER_LAN75XX=y
	CONFIG_USB_ETHER_LAN78XX=y
	CONFIG_USB_ETHER_MCS7830=y
	CONFIG_USB_ETHER_RTL8152=y
	CONFIG_USB_ETHER_SMSC95XX=y

	As with built-in networking, you will also want to enable some network
	commands, for example:

	CONFIG_CMD_NET=y
	CONFIG_CMD_PING=y
	CONFIG_CMD_DHCP=y

	and some bootp options, which tell your board to obtain its subnet,
	gateway IP, host name and boot path from the bootp/dhcp server. These
	settings should start you off:

	#define CONFIG_BOOTP_SUBNETMASK
	#define CONFIG_BOOTP_GATEWAY
	#define CONFIG_BOOTP_HOSTNAME
	#define CONFIG_BOOTP_BOOTPATH

	You can also set the default IP address of your board and the server
	as well as the default file to load when a 'bootp' command is issued.
	However note that encoding these individual network settings into a
	common executable is discouraged, as it leads to potential conflicts,
	and all the parameters can either get stored in the board's external
	environment, or get obtained from the bootp server if not set.

	#define CONFIG_IPADDR 10.0.0.2 (replace with your value)
	#define CONFIG_SERVERIP 10.0.0.1 (replace with your value)
	#define CONFIG_BOOTFILE "uImage"

	The 'usb start' command should identify the adapter something like this:

	CrOS> usb start
	(Re)start USB...
	USB EHCI 1.00
	scanning bus for devices... 3 USB Device(s) found
	scanning bus for storage devices... 0 Storage Device(s) found
	scanning bus for ethernet devices... 1 Ethernet Device(s) found
	CrOS> print ethact
	ethact=asx0

	You can see that it found an ethernet device and we can print out the
	device name (asx0 in this case).

	Then 'bootp' or 'dhcp' should use it to obtain an IP address from DHCP,
	perhaps something like this:

	CrOS> bootp
	Waiting for Ethernet connection... done.
	BOOTP broadcast 1
	BOOTP broadcast 2
	DHCP client bound to address 172.22.73.81
	Using asx0 device
	TFTP from server 172.22.72.144; our IP address is 172.22.73.81
	Filename '/tftpboot/uImage-sjg-seaboard-261347'.
	Load address: 0x40c000
	Loading: #################################################################
	#################################################################
	#################################################################
	################################################
	done
	Bytes transferred = 3557464 (364858 hex)
	CrOS>


	Another way of doing this is to issue a tftp command, which will cause the
	bootp to happen automatically.


	MAC Addresses
	-------------

	Most Ethernet dongles have a built-in MAC address which is unique in the
	world. This is important so that devices on the network can be
	distinguished from each other. MAC address conflicts are evil and
	generally result in strange and erratic behaviour.

	Some boards have USB Ethernet chips on-board, and these sometimes do not
	have an assigned MAC address. In this case it is up to you to assign
	one which is unique. You should obtain a valid MAC address from a range
	assigned to you before you ship the product.

	Built-in Ethernet adapters support setting the MAC address by means of
	an ethaddr environment variable for each interface (ethaddr, eth1addr,
	eth2addr). There is similar support on the USB network side, using the
	names usbethaddr, usbeth1addr, etc. They are kept separate since we
	don't want a USB device taking the MAC address of a built-in device or
	vice versa.

	So if your USB Ethernet chip doesn't have a MAC address available then
	you must set usbethaddr to a suitable MAC address. At the time of
	writing this functionality is only supported by the SMSC driver.