- 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.
+
+ 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.
+