u-boot/doc/README.usb

5  * SPDX-License-Identifier:	GPL-2.0+
8 USB Support
11 The USB support is implemented on the base of the UHCI Host
14 Currently supported are USB Hubs, USB Keyboards, USB Floppys, USB
15 flash sticks and USB network adaptors.
16 Tested with a TEAC Floppy TEAC FD-05PUB and Chicony KU-8933 Keyboard.
19 -------------
21 The USB (at least the USB UHCI) needs a frame list (4k), transfer
24 frame pointer. This may cause to crash the OS during boot. So the USB
25 _MUST_ be stopped during OS boot. This is the reason, why the USB is
26 NOT automatically started during start-up. If someone needs the USB
30 For USB keyboards this can be done by a script which is automatically
31 started after the U-Boot is up and running. To boot an OS with a an
32 USB keyboard another script is necessary, which first disables the
33 USB and then executes the boot command. If the boot command fails,
34 the script can reenable the USB kbd.
36 Common USB Commands:
37 - usb start:
38 - usb reset:	    (re)starts the USB. All USB devices will be
39 		    initialized and a device tree is build for them.
40 - usb tree:	    shows all USB devices in a tree like display
41 - usb info [dev]:   shows all USB infos of the device dev, or of all
43 - usb stop [f]:	    stops the USB. If f==1 the USB will also stop if
44 		    an USB keyboard is assigned as stdin. The stdin
46 Storage USB Commands:
47 - usb scan:	    scans the USB for storage devices.The USB must be
48 		    running for this command (usb start)
49 - usb device [dev]: show or set current USB storage device
50 - usb part [dev]:   print partition table of one or all USB storage
52 - usb read addr blk# cnt:
55 - usbboot addr dev:part:
56 		    boot from USB device
59 ----------------
60 CONFIG_CMD_USB	    enables basic USB support and the usb command
61 CONFIG_USB_UHCI	    defines the lowlevel part.A lowlevel part must be defined
63 CONFIG_USB_KEYBOARD enables the USB Keyboard
64 CONFIG_USB_STORAGE  enables the USB storage devices
65 CONFIG_USB_HOST_ETHER	enables USB ethernet adapter support
68 USB Host Networking
71 If you have a supported USB Ethernet adapter you can use it in U-Boot
72 to obtain an IP address and load a kernel from a network server.
74 Note: USB Host Networking is not the same as making your board act as a USB
76 and will appear as a network interface to an attached computer. In that
77 case the connection is via a USB cable with the computer acting as the host.
79 With USB Host Networking, your board is the USB host. It controls the
87 --------------
91 to a Linux machine and typing 'lsusb'. The drivers are in
92 drivers/usb/eth.
94 For example this lsusb output line shows a device with Vendor ID 0x0x95
99 If you look at drivers/usb/eth/asix.c you will see this line within the
102 	{ 0x0b95, 0x7720 },	/* Trendnet TU2-ET100 V3.0R */
104 If your adapter is not listed there is a still a chance that it will
106 or take the adapter apart and look for chip markings. Then add a line
108 build U-Boot and see if it works. If not then there might be differences
109 between the chip in your adapter and the driver. You could try to get a
110 datasheet for your device and add support for it to U-Boot. This is not
111 particularly difficult - you only need to provide support for four basic
115 Enabling USB Host Networking
116 ----------------------------
118 The normal U-Boot commands are used with USB networking, but you must
119 start USB first. For example:
121 usb start
126 To enable USB Host Ethernet in U-Boot, your platform must of course
127 support USB with CONFIG_CMD_USB enabled and working. You will need to
130 CONFIG_CMD_USB=y		/* the 'usb' interactive command */
131 CONFIG_USB_HOST_ETHER=y		/* Enable USB Ethernet adapters */
143 As with built-in networking, you will also want to enable some network
160 as well as the default file to load when a 'bootp' command is issued.
161 However note that encoding these individual network settings into a
171 The 'usb start' command should identify the adapter something like this:
173 CrOS> usb start
174 (Re)start USB...
175 USB EHCI 1.00
176 scanning bus for devices... 3 USB Device(s) found
195 Filename '/tftpboot/uImage-sjg-seaboard-261347'.
206 Another way of doing this is to issue a tftp command, which will cause the
211 -------------
213 Most Ethernet dongles have a built-in MAC address which is unique in the
218 Some boards have USB Ethernet chips on-board, and these sometimes do not
220 one which is unique. You should obtain a valid MAC address from a range
223 Built-in Ethernet adapters support setting the MAC address by means of
225 eth2addr). There is similar support on the USB network side, using the
227 don't want a USB device taking the MAC address of a built-in device or
230 So if your USB Ethernet chip doesn't have a MAC address available then
231 you must set usbethaddr to a suitable MAC address. At the time of