mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-06-09 23:36:03 +09:00
2fbb8462b0
As the help message of CONFIG_BOOTDELAY says, CONFIG_BOOTDELAY=-2
means the autoboot with no delay, with no abort check even if
CONFIG_ZERO_BOOTDELAY_CHECK is defined.
To sum up, the autoboot behaves as follows:
[1] CONFIG_BOOTDELAY=0 && CONFIG_ZERO_BOOTDELAY_CHECK=y
autoboot with no delay, but you can abort it by key input
[2] CONFIG_BOOTDELAY=0 && CONFIG_ZERO_BOOTDELAY_CHECK=n
autoboot with no delay, with no check for abort
[3] CONFIG_BOOTDELAY=-1
disable autoboot
[4] CONFIG_BOOTDELAY=-2
autoboot with no delay, with no check for abort
As you notice, [2] and [4] come to the same result, which means we
do not need CONFIG_ZERO_BOOTDELAY_CHECK. We can control all the
cases only by CONFIG_BOOTDELAY, like this:
[1] CONFIG_BOOTDELAY=0
autoboot with no delay, but you can abort it by key input
[2] CONFIG_BOOTDELAY=-1
disable autoboot
[3] CONFIG_BOOTDELAY=-2
autoboot with no delay, with no check for abort
This commit converts the logic as follow:
CONFIG_BOOTDELAY=0 && CONFIG_ZERO_BOOTDELAY_CHECK=n
--> CONFIG_BOOTDELAY=-2
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Acked-by: Christian Riesch <christian.riesch@omicronenergy.com>
Acked-by: Hannes Schmelzer <hannes.schmelzer@br-automation.com>
140 lines
5.0 KiB
Plaintext
140 lines
5.0 KiB
Plaintext
/*
|
|
* (C) Copyright 2001
|
|
* Dave Ellis, SIXNET, dge@sixnetio.com
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0+
|
|
*/
|
|
|
|
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_KEYED_CTRLC
|
|
CONFIG_AUTOBOOT_PROMPT
|
|
CONFIG_AUTOBOOT_DELAY_STR
|
|
CONFIG_AUTOBOOT_STOP_STR
|
|
|
|
"bootdelaykey" environment variable
|
|
"bootstopkey" 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.
|
|
|
|
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.
|
|
|
|
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_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.
|