readme

blob1.0是最早版本的sa1100的bootloader

(emacs users can use -*- outline -*- mode for this file)

$Id: README,v 1.7 1999/10/03 22:03:52 erikm Exp $

* Info
======

** What is blob?
----------------

Blob is the Boot Loader OBject, the boot loader for the LART. Blob is
able to boot a Linux kernel stored in flash or RAM and provide that
kernel with a ramdisk (again from flash or RAM).

Blob is copyrighted by Jan-Derk Bakker ([e-mail]) and
Erik Mouw ([e-mail]). Blob is released with a GNU GPL
license.




** So what is LART?
-------------------

LART is the Linux Advanced Radio Terminal, a small low power computing
element used in the MMC project (http://mmc.et.tudelft.nl/ and
http://www-ict.its.tudelft.nl/~erik/open-source/LART/).

LART features:

- 10x7.5 cm (that's 4x3 inch in Stonehenge Units)
- 220 MHz Digital StrongARM SA-1100 CPU
- 4 Mbyte flash memory
- 32 Mbyte DRAM memory
- Low power: peak power consumption is 1W




* Building blob
===============

** Prerequisites
----------------

- A native ARM/StrongARM Linux system with egcs 1.1.2 or gcc 2.95, and
  binutils 2.9.1.0.19 or better
- Or any UNIX system with cross compiling binutils 2.9.1.0.19 (or
  better) and gcc 2.95 (or egcs 1.1.2) installed
- GNU make (although some vendor supplied make utilities will do)
- GNU autoconf and automake (if you build blob from CVS)




** Generating configure and Makefiles
-------------------------------------

This step is only necessary if you build blob from CVS.

- Run "tools/rebuild-gcc" ttwwiiccee




** Configuring and compiling the package
----------------------------------------

With a cross compiler tool chain:

- setenv CC /path/to/cross/gcc
- setenv OBJCOPY /path/to/cross/objcopy
- Run "./configure --target=arm-lart-linux-gnu --host=i386-unknown-linux \
       --with-linux-prefix=/path/to/armlinux/source"
  Use the appropriate host OS for the --host flag
- Run "make"


With a native ARM Linux tool chain:

- Run "./configure" 
- Run "make"


The binary image is in src/blob, src/blob-elf32 is the image with
complete ELF headers. To disassemble "blob-elf32", use:

  objdump --disassemble-all blob-elf32

To see the actual hex codes of blob, use:

  od -t x4 blob




** Installing
-------------

Use whatever tool you need to download the blob image (src/blob) at
address 0x00000000 of your SA-1100 target. The LART project currently
uses the following wisdom to install blob:

Required hardware & software:
- The LART itself with 4 Mbyte flash memory
- An external 128 kbyte flash board
- A PCI 7200 (???) digital I/O card with a Linux driver
- A flash burn program for this I/O card

The external flash board is connected to the PCI 7200 card and blob is
written into the flash memory using the flash burn program. The
external flash board is connected to the LART low speed interface. The
external flash chip is mapped at address 0x00000000, and the internal
flash is remapped at 0x08000000. As soon as the LART boots, the
external flash is copied to the first 128 kbyte of the internal
flash. The next time the LART is started without external flash board,
it starts from its internal flash which now contains the just
downloaded blob.

Why this strange way to download blob? We first tried to use the
SA-1100 JTAG interface to program the flash directly, but soon found
out that it would take weeks to write a decent JTAG tool because JTAG
is a real brain-damaged protocol (it was designed by a committee). To
meet a deadline, we decided to make a special board with 128 kbyte
external flash memory (and an LCD interface).




** Making a distribution
------------------------

This is only needed when you want to make a tar file from the current
blob sources.

- First configure the package
- Run "make dist"




* Using blob on the LART
========================

** Booting
----------

First connect a terminal (or a terminal emulator like miniterm or
Seyon) to the LART's serial port. Use the following settings for your
terminal: 9600 baud, 8 data bits, no parity, 1 stop bit, no start bits
(9600 8N1, a pretty standard setting for Unix systems). If possible,
use VT100 terminal emulation. Switch on the power to the LART. The
LART should respond with:

  Consider yourself LARTed!
  Running from internal Flash.
  Starting the memory tester...
  Zeroing memory...0xD0000000
  Zeroing done. Testing for aliases...
  Loading kernel from flash ....... done
  Loading ramdisk from flash ............... done

  blob version 1.0.0, Copyright (C) 1999 Jan-Derk Bakker and Erik Mouw.
  blob comes with ABSOLUTELY NO WARRANTY; read the GNU GPL for details.
  This is free software, and you are welcome to redistribute it
  under certain conditions; read the GNU GPL for details.

  Autoboot in progress, press <enter> to stop ...

If you don't press the <enter> key within 10 seconds, blob will
automatically start the Linux kernel:

  Starting kernel ...

  Uncompressing Linux...done.
  Now booting the kernel
  ...

However, if you press the <enter> key, you will get the blob
prompt:

  Autoboot aborted
  Type "help" to get a list of commands
  blob> 




** Commands
-----------

Blob knows several commands, typing "help" (without the ") will show
you which:

  Help for blob 1.0.0, the LART bootloader
  The following commands are supported:
  * boot [kernel options]      Boot Linux with optional kernel options
  * download {kernel|ramdisk}  Download kernel or ramdisk image to RAM
  * flash {kernel|ramdisk}     Copy kernel or ramdisk from RAM to flash
  * help                       Get this help
  * reload {kernel|ramdisk}    Reload kernel or ramdisk from flash to RAM
  * reset                      Reset terminal
  * speed                      Set download speed
  * status                     Display current status




*** "boot"
--------------------

Boot the Linux kernel. You can supply extra parameters to the Linux
kernel, but the current version of blob will not pass them to the
kernel (this will change as soon as I find out how -- Erik). Blob will
respond with:

  blob> boot

  Starting kernel ...

  Uncompressing Linux...done.
  Now booting the kernel
  ...




*** "download"
--------------

Download a uuencoded kernel or ramdisk to the LART RAM. This command
needs an extra parameter: "kernel" or "ramdisk". Blob will respond
with:

  blob> download kernel
  Switching to 115200 baud
  You have 60 seconds to switch your terminal emulator to the same speed and
  start downloading. After that blob will switch back to 9600 baud.

Switch your terminal emulator to the indicated speed and start
downloading the kernel or ramdisk. With minicom, you can use the ASCII
download method, or use another shell to download the file:

  uuencode zImage zImage > /dev/ttyS1

Of course, use the correct serial port. If the download is successful,
blob will respond with:

  (Please switch your terminal emulator back to 9600 baud)
  Received 65536 (0x00010000) bytes.

If an error occurs during downloading, blob will respond with:

  (Please switch your terminal emulator back to 9600 baud)
  *** Uudecode receive failed

A failed download session can have several reasons: the file is too
big, the download speed too high (see the "speed" command), or the
uuencoded file to be downloaded is corrupt. Correct the error and
retry.

A downloaded kernel or ramdisk can be written to flash with the
"flash" command, or it can directly be used to boot with the "boot"
command.




*** "flash"
-----------

Write the kernel or ramdisk from RAM to flash memory. This command
needs an extra parameter: "kernel" or "ramdisk". Blob will respond
with:

  blob> flash kernel
  Saving kernel to flash ..... .................... done

Currently this command only works when blob is started from the
external flash board.




*** "reload"
------------

Reload the kernel or ramdisk from flash memory to RAM. This command
needs an extra parameter: "kernel" or "ramdisk". Blob will respond
with:

  blob> reload kernel
  Loading kernel from flash ....... done

The "reload command" will overwrite a just downloaded a kernel or ramdisk.




*** "reset"
-----------

Reset the terminal. This command will write the VT100 reset sequence
(Esc-c) to the terminal. Useful if you forgot to switch your terminal
emulator back to 9600 baud after downloading a kernel or ramdisk.




*** "speed"
-----------

Set the download speed. This command needs a download speed value as
an extra parameter. Valid values are: 1200, 9600, 19200, 38400, 57600,
and 115200. Blob will respond with:

  blob> speed 19200
  Download speed set to 19200 baud




*** "status"
------------

Show the current status. Blob will respond with:

  blob> status
  Bootloader    : blob
  Version       : 1.0.0
  Running from  : internal flash
  Blocksize     : 0x00800000
  Download speed: 115200 baud
  Kernel        : downloaded, 424333 bytes
  Ramdisk       : from flash

Depending on what commands you used before, these values may or may
not be different.