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#
# (C) Copyright 2000 - 2004
# Wolfgang Denk, DENX Software Engineering, [e-mail].
#
# See file CREDITS for list of people who contributed to this
# project.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of
# the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA 02111-1307 USA
#

Summary:
========

This directory contains the source code for U-Boot-aesop, a boot loader for
Embedded boards based on ARM only which can be installed in a boot ROM and used to
initialize and test the hardware or to download and run application
code.

The development of U-Boot-aesop is closely related to Linux: some parts of
the source code originate in the Linux source tree, we have some
header files in common, and special provision has been made to
support booting of Linux images.

Some attention has been paid to make this software easily
configurable and extendable. For instance, all monitor commands are
implemented with the same call interface, so that it's very easy to
add new commands. Also, instead of permanently adding rarely used
code (for instance hardware test utilities) to the monitor, you can
load and run it dynamically.


Status:
=======

In general, all boards for which a configuration option exists in the
Makefile have been tested to some extent and can be considered
"working". In fact, many of them are used in production systems.

In case of problems see the CHANGELOG and CREDITS files to find out
who contributed the specific port.


Where to get help:
==================

In case you have questions about, problems with or contributions for
U-Boot-aesop you should send a message to the U-Boot-aesop mailing list at
<[e-mail]>. There is also an archive of
previous traffic on the mailing list - please search the archive
before asking FAQ's. Please see
http://lists.sourceforge.net/lists/listinfo/u-boot-aesop-users/


Where we come from:
===================

- start from www.kernelproject.org and elinux in daum.net
- next please ...

Versioning:
===========

U-Boot-aesop uses a 3 level version number containing a version, a
sub-version, and a patchlevel: "U-Boot-aesop-2.34.5" means version "2",
sub-version "34", and patchlevel "4".

The patchlevel is used to indicate certain stages of development
between released versions, i. e. officially released versions of
U-Boot-aesop will always have a patchlevel of "0".


Directory Hierarchy:
====================

- board		Board dependent files
  - aesop2440   aesop board 
- common	Misc architecture independent functions
- cpu		CPU specific files
  - arm920t	Files specific to ARM 920 CPUs
- disk		Code for disk drive partition handling
- doc		Documentation (don't expect too much)
- drivers	Commonly used device drivers
- dtt		Digital Thermometer and Thermostat drivers
- examples	Example code for standalone applications, etc.
- include	Header Files
- lib_arm	Files generic to ARM	 architecture
- lib_generic	Files generic to all	 architectures
- net		Networking code
- post		Power On Self Test
- rtc		Real Time Clock drivers
- tools		Tools to build S-Record or U-Boot-aesop images, etc.

Software Configuration:
=======================

Configuration is usually done using C preprocessor defines; the
rationale behind that is to avoid dead code whenever possible.

There are two classes of configuration variables:

* Configuration _OPTIONS_:
  These are selectable by the user and have names beginning with
  "CONFIG_".

* Configuration _SETTINGS_:
  These depend on the hardware etc. and should not be meddled with if
  you don't know what you're doing; they have names beginning with
  "CFG_".

Later we will add a configuration tool - probably similar to or even
identical to what's used for the Linux kernel. Right now, we have to
do the configuration by hand, which means creating some symbolic
links and editing some configuration files. We use the TQM8xxL boards
as an example here.


Selection of Processor Architecture and Board Type:
---------------------------------------------------

For all supported boards there are ready-to-use default
configurations available; just type "make <board_name>_config".

Example: For a aesop2440 module type:

	cd u-boot-aesop-x.x.x
	make aesop2440_config

For the Cogent platform, you need to specify the cpu type as well;
e.g. "make cogent_arm920t_config". And also configure the cogent
directory according to the instructions in cogent/README.


Configuration Options:
----------------------

Configuration depends on the combination of board and CPU type; all
such information is kept in a configuration file
"include/configs/<board_name>.h".

Example: For a aesop2440 module, all configuration settings are in
"include/configs/aesop.h".


Many of the options are named exactly as the corresponding Linux
kernel configuration options. The intention is to make it easier to
build a config tool - later.


The following options need to be configured:

- CPU Type:	Define exactly one of

		ARM based CPUs:
		---------------
		CONFIG_SA1110
		CONFIG_ARM7
		CONFIG_PXA250

- Board Type:	Define exactly one of

		ARM based boards:
		-----------------
		CONFIG_AESOP2440	CONFIG_CONFIG_SMDK2410		CONFIG_SMDK2440	


- CPU Type:     Define exactly one of 

		CONFIG_S3C2440


- Linux Kernel Interface:
		CONFIG_CLOCKS_IN_MHZ

		U-Boot-aesop stores all clock information in Hz
		internally. For binary compatibility with older Linux
		kernels (which expect the clocks passed in the
		bd_info data to be in MHz) the environment variable
		"clocks_in_mhz" can be defined so that U-Boot-aesop
		converts clock data to MHZ before passing it to the
		Linux kernel.
		When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
		"clocks_in_mhz=1" is  automatically  included  in  the
		default environment.

		CONFIG_MEMSIZE_IN_BYTES		[relevant for MIPS only]

		When transfering memsize parameter to linux, some versions
		expect it to be in bytes, others in MB.
		Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.

- Serial Ports:
		CFG_PL010_SERIAL

		Define this if you want support for Amba PrimeCell PL010 UARTs.

		CFG_PL011_SERIAL

		Define this if you want support for Amba PrimeCell PL011 UARTs.

		CONFIG_PL011_CLOCK

		If you have Amba PrimeCell PL011 UARTs, set this variable to
		the clock speed of the UARTs.

		CONFIG_PL01x_PORTS

		If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
		define this to a list of base addresses for each (supported)
		port. See e.g. include/configs/versatile.h


- Console Interface:
		Depending on board, define exactly one serial port
		(like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
		CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
		console by defining CONFIG_8xx_CONS_NONE

		Note: if CONFIG_8xx_CONS_NONE is defined, the serial
		port routines must be defined elsewhere
		(i.e. serial_init(), serial_getc(), ...)

		CONFIG_CFB_CONSOLE
		Enables console device for a color framebuffer. Needs following
		defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
			VIDEO_FB_LITTLE_ENDIAN	graphic memory organisation
						(default big endian)
			VIDEO_HW_RECTFILL	graphic chip supports
						rectangle fill
						(cf. smiLynxEM)
			VIDEO_HW_BITBLT		graphic chip supports
						bit-blit (cf. smiLynxEM)
			VIDEO_VISIBLE_COLS	visible pixel columns
						(cols=pitch)
			VIDEO_VISIBLE_ROWS	visible pixel rows
			VIDEO_PIXEL_SIZE	bytes per pixel
			VIDEO_DATA_FORMAT	graphic data format
						(0-5, cf. cfb_console.c)
			VIDEO_FB_ADRS		framebuffer address
			VIDEO_KBD_INIT_FCT	keyboard int fct
						(i.e. i8042_kbd_init())
			VIDEO_TSTC_FCT		test char fct
						(i.e. i8042_tstc)
			VIDEO_GETC_FCT		get char fct
						(i.e. i8042_getc)
			CONFIG_CONSOLE_CURSOR	cursor drawing on/off
						(requires blink timer
						cf. i8042.c)
			CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
			CONFIG_CONSOLE_TIME	display time/date info in
						upper right corner
						(requires CFG_CMD_DATE)
			CONFIG_VIDEO_LOGO	display Linux logo in
						upper left corner
			CONFIG_VIDEO_BMP_LOGO	use bmp_logo.h instead of
						linux_logo.h for logo.
						Requires CONFIG_VIDEO_LOGO
			CONFIG_CONSOLE_EXTRA_INFO
						addional board info beside
						the logo

		When CONFIG_CFB_CONSOLE is defined, video console is
		default i/o. Serial console can be forced with
		environment 'console=serial'.

		When CONFIG_SILENT_CONSOLE is defined, all console
		messages (by U-Boot-aesop and Linux!) can be silenced with
		the "silent" environment variable. See
		doc/README.silent for more information.

- Console Baudrate:
		CONFIG_BAUDRATE - in bps
		Select one of the baudrates listed in
		CFG_BAUDRATE_TABLE, see below.
		CFG_BRGCLK_PRESCALE, baudrate prescale

- Interrupt driven serial port input:
		CONFIG_SERIAL_SOFTWARE_FIFO

		PPC405GP only.
		Use an interrupt handler for receiving data on the
		serial port. It also enables using hardware handshake
		(RTS/CTS) and UART's built-in FIFO. Set the number of
		bytes the interrupt driven input buffer should have.

		Leave undefined to disable this feature, including
		disable the buffer and hardware handshake.

- Console UART Number:
		CONFIG_UART1_CONSOLE

		IBM PPC4xx only.
		If defined internal UART1 (and not UART0) is used
		as default U-Boot-aesop console.

- Boot Delay:	CONFIG_BOOTDELAY - in seconds
		Delay before automatically booting the default image;
		set to -1 to disable autoboot.

		See doc/README.autoboot for these options that
		work with CONFIG_BOOTDELAY. None are required.
		CONFIG_BOOT_RETRY_TIME
		CONFIG_BOOT_RETRY_MIN
		CONFIG_AUTOBOOT_KEYED
		CONFIG_AUTOBOOT_PROMPT
		CONFIG_AUTOBOOT_DELAY_STR
		CONFIG_AUTOBOOT_STOP_STR
		CONFIG_AUTOBOOT_DELAY_STR2
		CONFIG_AUTOBOOT_STOP_STR2
		CONFIG_ZERO_BOOTDELAY_CHECK
		CONFIG_RESET_TO_RETRY

- Autoboot Command:
		CONFIG_BOOTCOMMAND
		Only needed when CONFIG_BOOTDELAY is enabled;
		define a command string that is automatically executed
		when no character is read on the console interface
		within "Boot Delay" after reset.

		CONFIG_BOOTARGS
		This can be used to pass arguments to the bootm
		command. The value of CONFIG_BOOTARGS goes into the
		environment value "bootargs".

		CONFIG_RAMBOOT and CONFIG_NFSBOOT
		The value of these goes into the environment as
		"ramboot" and "nfsboot" respectively, and can be used
		as a convenience, when switching between booting from
		ram and nfs.

- Pre-Boot Commands:
		CONFIG_PREBOOT

		When this option is #defined, the existence of the
		environment variable "preboot" will be checked
		immediately before starting the CONFIG_BOOTDELAY
		countdown and/or running the auto-boot command resp.
		entering interactive mode.

		This feature is especially useful when "preboot" is
		automatically generated or modified. For an example
		see the LWMON board specific code: here "preboot" is
		modified when the user holds down a certain
		combination of keys on the (special) keyboard when
		booting the systems

- Serial Download Echo Mode:
		CONFIG_LOADS_ECHO
		If defined to 1, all characters received during a
		serial download (using the "loads" command) are
		echoed back. This might be needed by some terminal
		emulations (like "cu"), but may as well just take
		time on others. This setting #define's the initial
		value of the "loads_echo" environment variable.

- Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
		CONFIG_KGDB_BAUDRATE
		Select one of the baudrates listed in
		CFG_BAUDRATE_TABLE, see below.

- Monitor Functions:
		CONFIG_COMMANDS
		Most monitor functions can be selected (or
		de-selected) by adjusting the definition of
		CONFIG_COMMANDS; to select individual functions,
		#define CONFIG_COMMANDS by "OR"ing any of the
		following values:

		#define enables commands:
		-------------------------
		CFG_CMD_ASKENV	* ask for env variable
		CFG_CMD_AUTOSCRIPT Autoscript Support
		CFG_CMD_BDI	  bdinfo
		CFG_CMD_BEDBUG	* Include BedBug Debugger
		CFG_CMD_BMP	* BMP support
		CFG_CMD_BSP	* Board specific commands
		CFG_CMD_BOOTD	  bootd
		CFG_CMD_CACHE	* icache, dcache
		CFG_CMD_CONSOLE	  coninfo
		CFG_CMD_DATE	* support for RTC, date/time...
		CFG_CMD_DHCP	* DHCP support
		CFG_CMD_DIAG	* Diagnostics
		CFG_CMD_DOC	* Disk-On-Chip Support
		CFG_CMD_DTT	* Digital Therm and Thermostat
		CFG_CMD_ECHO	* echo arguments
		CFG_CMD_EEPROM	* EEPROM read/write support
		CFG_CMD_ELF	* bootelf, bootvx
		CFG_CMD_ENV	  saveenv
		CFG_CMD_FDC	* Floppy Disk Support
		CFG_CMD_FAT	* FAT partition support
		CFG_CMD_FDOS	* Dos diskette Support
		CFG_CMD_FLASH	  flinfo, erase, protect
		CFG_CMD_FPGA	  FPGA device initialization support