X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=doc%2FREADME.autoboot;h=14e3660dd8d7634e058d280bed1e457de8838066;hb=14b256e5c084e1b693f4ad73c6a8beee7ffcb4af;hp=20736ca47634beb49a6654c7437358fb3662b0b0;hpb=cc1c8a136f9813d0a9cb9a94d2f12206873ddc4e;p=u-boot diff --git a/doc/README.autoboot b/doc/README.autoboot index 20736ca476..14e3660dd8 100644 --- a/doc/README.autoboot +++ b/doc/README.autoboot @@ -2,23 +2,7 @@ * (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 + * SPDX-License-Identifier: GPL-2.0+ */ Using autoboot configuration options @@ -67,92 +51,107 @@ What they do CONFIG_BOOT_RETRY_TIME CONFIG_BOOT_RETRY_MIN - bootretry environment variable + "bootretry" environment variable - These options determine what happens after autoboot is - stopped and U-Boot is waiting for commands. + 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. + 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 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. + 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_KEYED_CTRLC 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 + "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. + 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, + 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_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. + + Note that CONFIG_AUTOBOOT_PROMPT is used as the (only) + argument to a printf() call, so it may contain '%' format + specifications, provided that it also includes, sepearated by + commas exactly like in a printf statement, the required + arguments. It is the responsibility of the user to select only + such arguments that are valid in the given context. A + reasonable prompt could be defined as + + #define CONFIG_AUTOBOOT_PROMPT \ + "autoboot in %d seconds\n",bootdelay + + 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 #define or the + "bootdelaykey2" environment variable and/or the + CONFIG_AUTOBOOT_STOP_STR2 #define or the "bootstopkey" + environment variable you can specify a second, alternate + string (which allows you to have two "password" strings). + + The CONFIG_AUTOBOOT_KEYED_CTRLC #define allows for the boot + sequence to be interrupted by ctrl-c, in addition to the + "bootdelaykey" and "bootstopkey". Setting this variable + provides an escape sequence from the limited "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. + 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. - + (Only effective when CONFIG_BOOT_RETRY_TIME is also set) + After the countdown timed out, the board will be reset to restart + again.