diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/README.OXC | 25 | ||||
| -rw-r--r-- | doc/README.autoboot | 158 | ||||
| -rw-r--r-- | doc/README.console | 118 |
3 files changed, 301 insertions, 0 deletions
diff --git a/doc/README.OXC b/doc/README.OXC new file mode 100644 index 0000000..e7bb76f --- /dev/null +++ b/doc/README.OXC @@ -0,0 +1,25 @@ +This document contains different information about the port +of U-Boot for the OXC board designed by Lucent Technologies, +Inc. + +1. Showing activity + +U-Boot for the OXC board can show its current status using +the Active LED. This feature is configured by the following +options: + +CONFIG_SHOW_ACTIVITY + + When this option is on, the Active LED is blinking fast +when U-Boot runs in the idle loop (i.e. waits for user +commands from serial console) and blinking slow when it +downloads an image over network. When U-Boot loads an image +over serial line the Active LED does not blink and its state +is random (i.e. either constant on or constant off). + +CONFIG_SHOW_BOOT_PROGRESS + + When this option is on, U-Boot switches the Active LED +off before booting an image and switches it on if booting +failed due to some reasons. + diff --git a/doc/README.autoboot b/doc/README.autoboot new file mode 100644 index 0000000..20736ca --- /dev/null +++ b/doc/README.autoboot @@ -0,0 +1,158 @@ +/* + * (C) Copyright 2001 + * Dave Ellis, SIXNET, dge@sixnetio.com + * + * 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 + */ + +Using autoboot configuration options +==================================== + +The basic autoboot configuration options are documented in the main +U-Boot README. See it for details. They are: + + bootdelay + bootcmd + CONFIG_BOOTDELAY + CONFIG_BOOTCOMMAND + +Some additional options that make autoboot safer in a production +product are documented here. + +Why use them? +------------- + +The basic autoboot feature allows a system to automatically boot to +the real application (such as Linux) without a user having to enter +any commands. If any key is pressed before the boot delay time +expires, U-Boot stops the autoboot process, gives a U-Boot prompt +and waits forever for a command. That's a good thing if you pressed a +key because you wanted to get the prompt. + +It's not so good if the key press was a stray character on the +console serial port, say because a user who knows nothing about +U-Boot pressed a key before the system had time to boot. It's even +worse on an embedded product that doesn't have a console during +normal use. The modem plugged into that console port sends a +character at the wrong time and the system hangs, with no clue as to +why it isn't working. + +You might want the system to autoboot to recover after an external +configuration program stops autoboot. If the configuration program +dies or loses its connection (modems can disconnect at the worst +time) U-Boot will patiently wait forever for it to finish. + +These additional configuration options can help provide a system that +boots when it should, but still allows access to U-Boot. + +What they do +------------ + + CONFIG_BOOT_RETRY_TIME + CONFIG_BOOT_RETRY_MIN + + bootretry environment variable + + These options determine what happens after autoboot is + stopped and U-Boot is waiting for commands. + + CONFIG_BOOT_RETRY_TIME must be defined to enable the boot + retry feature. If the environment variable 'bootretry' is + found then its value is used, otherwise the retry timeout is + CONFIG_BOOT_RETRY_TIME. CONFIG_BOOT_RETRY_MIN is optional and + defaults to CONFIG_BOOT_RETRY_TIME. All times are in seconds. + + If the retry timeout is negative, the U-Boot command prompt + never times out. Otherwise it is forced to be at least + CONFIG_BOOT_RETRY_MIN seconds. If no valid U-Boot command is + entered before the specified time the boot delay sequence is + restarted. Each command that U-Boot executes restarts the + timeout. + + If CONFIG_BOOT_RETRY_TIME < 0 the feature is there, but + doesn't do anything unless the environment variable + 'bootretry' is >= 0. + + CONFIG_AUTOBOOT_KEYED + CONFIG_AUTOBOOT_PROMPT + CONFIG_AUTOBOOT_DELAY_STR + CONFIG_AUTOBOOT_STOP_STR + CONFIG_AUTOBOOT_DELAY_STR2 + CONFIG_AUTOBOOT_STOP_STR2 + + bootdelaykey environment variable + bootstopkey environment variable + bootdelaykey2 environment variable + bootstopkey2 environment variable + + These options give more control over stopping autoboot. When + they are used a specific character or string is required to + stop or delay autoboot. + + Define CONFIG_AUTOBOOT_KEYED (no value required) to enable + this group of options. CONFIG_AUTOBOOT_DELAY_STR, + CONFIG_AUTOBOOT_STOP_STR or both should be specified (or + specified by the corresponding environment variable), + otherwise there is no way to stop autoboot. + + CONFIG_AUTOBOOT_PROMPT is displayed before the boot delay + selected by CONFIG_BOOTDELAY starts. If it is not defined + there is no output indicating that autoboot is in progress. + If "%d" is included, it is replaced by the number of seconds + remaining before autoboot will start, but it does not count + down the seconds. "autoboot in %d seconds\n" is a reasonable + prompt. + + If CONFIG_AUTOBOOT_DELAY_STR or bootdelaykey is specified and + this string is received from console input before autoboot + starts booting, U-Boot gives a command prompt. The U-Boot + prompt will time out if CONFIG_BOOT_RETRY_TIME is used, + otherwise it never times out. + + If CONFIG_AUTOBOOT_STOP_STR or bootstopkey is specified and + this string is received from console input before autoboot + starts booting, U-Boot gives a command prompt. The U-Boot + prompt never times out, even if CONFIG_BOOT_RETRY_TIME is + used. + + The string recognition is not very sophisticated. If a + partial match is detected, the first non-matching character + is checked to see if starts a new match. There is no check + for a shorter partial match, so it's best if the first + character of a key string does not appear in the rest of the + string. + + Using the CONFIG_AUTOBOOT_DELAY_STR2 / bootdelaykey2 and/or + CONFIG_AUTOBOOT_STOP_STR2 / bootstopkey #defines and/or + environment variables you can specify a second, alternate + string (which allows you to haw two "password" strings). + + CONFIG_ZERO_BOOTDELAY_CHECK + + If this option is defined, you can stop the autoboot process + by hitting a key even in that case when "bootdelay" has been + set to 0. You can set "bootdelay" to a negative value to + prevent the check for console input. + + CONFIG_RESET_TO_RETRY + + (Only effective when CONFIG_BOOT_RETRY_TIME is also set) + After the countdown timed out, the board will be reset to restart + again. + diff --git a/doc/README.console b/doc/README.console new file mode 100644 index 0000000..6d477df --- /dev/null +++ b/doc/README.console @@ -0,0 +1,118 @@ +/* + * (C) Copyright 2000 + * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it + * + * 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 + */ + +U-Boot console handling +======================== + +HOW THE CONSOLE WORKS? +---------------------- + +At system startup U-Boot initializes a serial console. When U-Boot +relocates itself to RAM, all console drivers are initialized (they +will register all detected console devices to the system for further +use). + +If not defined in the environment, the first input device is assigned +to the 'stdin' file, the first output one to 'stdout' and 'stderr'. + +You can use the command "coninfo" to see all registered console +devices and their flags. You can assign a standard file (stdin, +stdout or stderr) to any device you see in that list simply by +assigning its name to the corresponding environment variable. For +example: + + setenv stdin wl_kbd <- To use the wireless keyboard + setenv stdout video <- To use the video console + +Do a simple "saveenv" to save the console settings in the environment +and get them working on the next startup, too. + +HOW CAN I USE STANDARD FILE INTO THE SOURCES? +--------------------------------------------- + +You can use the following functions to access the console: + +* STDOUT: + putc (to put a char to stdout) + puts (to put a string to stdout) + printf (to format and put a string to stdout) + +* STDIN: + tstc (to test for the presence of a char in stdin) + getc (to get a char from stdin) + +* STDERR: + eputc (to put a char to stderr) + eputs (to put a string to stderr) + eprintf (to format and put a string to stderr) + +* FILE (can be 'stdin', 'stdout', 'stderr'): + fputc (like putc but redirected to a file) + fputs (like puts but redirected to a file) + fprintf (like printf but redirected to a file) + ftstc (like tstc but redirected to a file) + fgetc (like getc but redirected to a file) + +Remember that all FILE-related functions CANNOT be used before +U-Boot relocation (done in 'board_init_r' in common/board.c). + +HOW CAN I USE STANDARD FILE INTO APPLICATIONS? +---------------------------------------------- + +Use the 'bd_mon_fnc' field of the bd_t structure passed to the +application to do everything you want with the console. + +But REMEMBER that that will work only if you have not overwritten any +U-Boot code while loading (or uncompressing) the image of your +application. + +For example, you won't get the console stuff running in the Linux +kernel because the kernel overwrites U-Boot before running. Only +some parameters like the framebuffer descriptors are passed to the +kernel in the high memory area to let the applications (the kernel) +use the framebuffers initialized by U-Boot. + +SUPPORTED DRIVERS +----------------- + +Working drivers: + + serial (architecture dependent serial stuff) + video (mpc8xx video controller) + +Work in progress: + + wl_kbd (Wireless 4PPM keyboard) + +Waiting for volounteers: + + lcd (mpc8xx lcd controller; to ) + +TESTED CONFIGURATIONS +--------------------- + +The driver has been tested with the following configurations (see +CREDITS for other contact informations): + +- MPC823FADS with AD7176 on a PAL TV (YCbYCr) - arsenio@tin.it +- GENIETV with AD7177 on a PAL TV (YCbYCr) - arsenio@tin.it |