1SPDX-License-Identifier: GPL-2.0+ 2/* 3 * (C) Copyright 2001 4 * Denis Peter, MPL AG Switzerland 5 */ 6 7USB Support 8=========== 9 10The USB support is implemented on the base of the UHCI Host 11controller. 12 13Currently supported are USB Hubs, USB Keyboards, USB Floppys, USB 14flash sticks and USB network adaptors. 15Tested with a TEAC Floppy TEAC FD-05PUB and Chicony KU-8933 Keyboard. 16 17How it works: 18------------- 19 20The USB (at least the USB UHCI) needs a frame list (4k), transfer 21descriptor and queue headers which are all located in the main memory. 22The UHCI allocates every millisecond the PCI bus and reads the current 23frame pointer. This may cause to crash the OS during boot. So the USB 24_MUST_ be stopped during OS boot. This is the reason, why the USB is 25NOT automatically started during start-up. If someone needs the USB 26he has to start it and should therefore be aware that he had to stop 27it before booting the OS. 28 29For USB keyboards this can be done by a script which is automatically 30started after the U-Boot is up and running. To boot an OS with a 31USB keyboard another script is necessary, which first disables the 32USB and then executes the boot command. If the boot command fails, 33the script can re-enable the USB keyboard. 34 35Common USB Commands: 36- usb start: 37- usb reset: (re)starts the USB. All USB devices will be 38 initialized and a device tree is build for them. 39- usb tree: shows all USB devices in a tree like display 40- usb info [dev]: shows all USB infos of the device dev, or of all 41 the devices 42- usb stop [f]: stops the USB. If f==1 the USB will also stop if 43 a USB keyboard is assigned as stdin. The stdin 44 is then switched to serial input. 45Storage USB Commands: 46- usb scan: scans the USB for storage devices. The USB must be 47 running for this command (usb start) 48- usb device [dev]: show or set current USB storage device 49- usb part [dev]: print partition table of one or all USB storage 50 devices 51- usb read addr blk# cnt: 52 read `cnt' blocks starting at block `blk#'to 53 memory address `addr' 54- usbboot addr dev:part: 55 boot from USB device 56 57Config Switches: 58---------------- 59CONFIG_CMD_USB enables basic USB support and the usb command 60CONFIG_USB_UHCI defines the lowlevel part. A lowlevel part must be defined 61 if using CONFIG_CMD_USB 62CONFIG_USB_KEYBOARD enables the USB Keyboard 63CONFIG_USB_STORAGE enables the USB storage devices 64CONFIG_USB_HOST_ETHER enables USB ethernet adapter support 65 66 67USB Host Networking 68=================== 69 70If you have a supported USB Ethernet adapter you can use it in U-Boot 71to obtain an IP address and load a kernel from a network server. 72 73Note: USB Host Networking is not the same as making your board act as a USB 74client. In that case your board is pretending to be an Ethernet adapter 75and will appear as a network interface to an attached computer. In that 76case the connection is via a USB cable with the computer acting as the host. 77 78With USB Host Networking, your board is the USB host. It controls the 79Ethernet adapter to which it is directly connected and the connection to 80the outside world is your adapter's Ethernet cable. Your board becomes an 81independent network device, able to connect and perform network operations 82independently of your computer. 83 84 85Device support 86-------------- 87 88Currently supported devices are listed in the drivers according to 89their vendor and product IDs. You can check your device by connecting it 90to a Linux machine and typing 'lsusb'. The drivers are in 91drivers/usb/eth. 92 93For example this lsusb output line shows a device with Vendor ID 0x0x95 94and product ID 0x7720: 95 96Bus 002 Device 010: ID 0b95:7720 ASIX Electronics Corp. AX88772 97 98If you look at drivers/usb/eth/asix.c you will see this line within the 99supported device list, so we know this adapter is supported. 100 101 { 0x0b95, 0x7720 }, /* Trendnet TU2-ET100 V3.0R */ 102 103If your adapter is not listed there is a still a chance that it will 104work. Try looking up the manufacturer of the chip inside your adapter. 105or take the adapter apart and look for chip markings. Then add a line 106for your vendor/product ID into the table of the appropriate driver, 107build U-Boot and see if it works. If not then there might be differences 108between the chip in your adapter and the driver. You could try to get a 109datasheet for your device and add support for it to U-Boot. This is not 110particularly difficult - you only need to provide support for four basic 111functions: init, halt, send and recv. 112 113 114Enabling USB Host Networking 115---------------------------- 116 117The normal U-Boot commands are used with USB networking, but you must 118start USB first. For example: 119 120usb start 121setenv bootfile /tftpboot/uImage 122bootp 123 124 125To enable USB Host Ethernet in U-Boot, your platform must of course 126support USB with CONFIG_CMD_USB enabled and working. You will need to 127add some settings to your board configuration: 128 129CONFIG_CMD_USB=y /* the 'usb' interactive command */ 130CONFIG_USB_HOST_ETHER=y /* Enable USB Ethernet adapters */ 131 132and one or more of the following for individual adapter hardware: 133 134CONFIG_USB_ETHER_ASIX=y 135CONFIG_USB_ETHER_ASIX88179=y 136CONFIG_USB_ETHER_LAN75XX=y 137CONFIG_USB_ETHER_LAN78XX=y 138CONFIG_USB_ETHER_MCS7830=y 139CONFIG_USB_ETHER_RTL8152=y 140CONFIG_USB_ETHER_SMSC95XX=y 141 142As with built-in networking, you will also want to enable some network 143commands, for example: 144 145CONFIG_CMD_NET=y 146CONFIG_CMD_PING=y 147CONFIG_CMD_DHCP=y 148 149and some bootp options, which tell your board to obtain its subnet, 150gateway IP, host name and boot path from the bootp/dhcp server. These 151settings should start you off: 152 153#define CONFIG_BOOTP_SUBNETMASK 154#define CONFIG_BOOTP_GATEWAY 155#define CONFIG_BOOTP_HOSTNAME 156#define CONFIG_BOOTP_BOOTPATH 157 158You can also set the default IP address of your board and the server 159as well as the default file to load when a 'bootp' command is issued. 160However note that encoding these individual network settings into a 161common executable is discouraged, as it leads to potential conflicts, 162and all the parameters can either get stored in the board's external 163environment, or get obtained from the bootp server if not set. 164 165#define CONFIG_IPADDR 10.0.0.2 (replace with your value) 166#define CONFIG_SERVERIP 10.0.0.1 (replace with your value) 167#define CONFIG_BOOTFILE "uImage" 168 169The 'usb start' command should identify the adapter something like this: 170 171CrOS> usb start 172(Re)start USB... 173USB EHCI 1.00 174scanning bus for devices... 3 USB Device(s) found 175 scanning bus for storage devices... 0 Storage Device(s) found 176 scanning bus for ethernet devices... 1 Ethernet Device(s) found 177CrOS> print ethact 178ethact=asx0 179 180You can see that it found an ethernet device and we can print out the 181device name (asx0 in this case). 182 183Then 'bootp' or 'dhcp' should use it to obtain an IP address from DHCP, 184perhaps something like this: 185 186CrOS> bootp 187Waiting for Ethernet connection... done. 188BOOTP broadcast 1 189BOOTP broadcast 2 190DHCP client bound to address 172.22.73.81 191Using asx0 device 192TFTP from server 172.22.72.144; our IP address is 172.22.73.81 193Filename '/tftpboot/uImage-sjg-seaboard-261347'. 194Load address: 0x40c000 195Loading: ################################################################# 196 ################################################################# 197 ################################################################# 198 ################################################ 199done 200Bytes transferred = 3557464 (364858 hex) 201CrOS> 202 203 204Another way of doing this is to issue a tftp command, which will cause the 205bootp to happen automatically. 206 207 208MAC Addresses 209------------- 210 211Most Ethernet dongles have a built-in MAC address which is unique in the 212world. This is important so that devices on the network can be 213distinguished from each other. MAC address conflicts are evil and 214generally result in strange and erratic behaviour. 215 216Some boards have USB Ethernet chips on-board, and these sometimes do not 217have an assigned MAC address. In this case it is up to you to assign 218one which is unique. You should obtain a valid MAC address from a range 219assigned to you before you ship the product. 220 221Built-in Ethernet adapters support setting the MAC address by means of 222an ethaddr environment variable for each interface (ethaddr, eth1addr, 223eth2addr). There is similar support on the USB network side, using the 224names usbethaddr, usbeth1addr, etc. They are kept separate since we 225don't want a USB device taking the MAC address of a built-in device or 226vice versa. 227 228So if your USB Ethernet chip doesn't have a MAC address available then 229you must set usbethaddr to a suitable MAC address. At the time of 230writing this functionality is only supported by the SMSC driver. 231