uboot/doc/README.usb
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   1/*
   2 * (C) Copyright 2001
   3 * Denis Peter, MPL AG Switzerland
   4 *
   5 * See file CREDITS for list of people who contributed to this
   6 * project.
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License as
  10 * published by the Free Software Foundation; either version 2 of
  11 * the License, or (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21 * MA 02111-1307 USA
  22 *
  23 */
  24
  25USB Support for PIP405 and MIP405 (UHCI)
  26========================================
  27
  28The USB support is implemented on the base of the UHCI Host
  29controller.
  30
  31Currently supported are USB Hubs, USB Keyboards and USB Floppys.
  32Tested with a TEAC Floppy TEAC FD-05PUB and Chicony KU-8933 Keyboard.
  33
  34How it works:
  35-------------
  36
  37The USB (at least the USB UHCI) needs a frame list (4k), transfer
  38descripor and queue headers which are all located in the main memory.
  39The UHCI allocates every milisecond the PCI bus and reads the current
  40frame pointer. This may cause to crash the OS during boot. So the USB
  41_MUST_ be stopped during OS boot. This is the reason, why the USB is
  42NOT automatically started during start-up. If someone needs the USB
  43he has to start it and should therefore be aware that he had to stop
  44it before booting the OS.
  45
  46For USB keyboards this can be done by a script which is automatically
  47started after the U-Boot is up and running. To boot an OS with a an
  48USB keyboard another script is necessary, which first disables the
  49USB and then executes the boot command. If the boot command fails,
  50the script can reenable the USB kbd.
  51
  52Common USB Commands:
  53- usb start:
  54- usb reset:        (re)starts the USB. All USB devices will be
  55                    initialized and a device tree is build for them.
  56- usb tree:         shows all USB devices in a tree like display
  57- usb info [dev]:   shows all USB infos of the device dev, or of all
  58                    the devices
  59- usb stop [f]:     stops the USB. If f==1 the USB will also stop if
  60                    an USB keyboard is assigned as stdin. The stdin
  61                    is then switched to serial input.
  62Storage USB Commands:
  63- usb scan:         scans the USB for storage devices.The USB must be
  64                    running for this command (usb start)
  65- usb device [dev]: show or set current USB staorage device
  66- usb part [dev]:   print partition table of one or all USB storage
  67                    devices
  68- usb read addr blk# cnt:
  69                    read `cnt' blocks starting at block `blk#'to
  70                    memory address `addr'
  71- usbboot addr dev:part:
  72                    boot from USB device
  73
  74Config Switches:
  75----------------
  76CONFIG_CMD_USB      enables basic USB support and the usb command
  77CONFIG_USB_UHCI     defines the lowlevel part.A lowlevel part must be defined
  78                    if using CONFIG_CMD_USB
  79CONFIG_USB_KEYBOARD enables the USB Keyboard
  80CONFIG_USB_STORAGE  enables the USB storage devices
  81