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authorHeinrich Schuchardt <xypron.glpk@gmx.de>2018-05-10 15:57:27 +0200
committerTom Rini <trini@konsulko.com>2018-05-23 17:30:04 -0400
commit3d9640f55cb22afd018135768209bd79a7907270 (patch)
tree10fbb65781851b46f12f59c0b35a76c8a8387673 /doc
parent78ccbd1395dd5c183086390d4bcd6760c7cb7996 (diff)
doc: expand README.commands
Describe U_BOOT_CMD_COMPLETE. Describe the arguments of U_BOOT_CMD and U_BOOT_CMD_COMPLETE. Describe the arguments of the command function. Describe the arguments of the completion function. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Diffstat (limited to 'doc')
-rw-r--r--doc/README.commands84
1 files changed, 74 insertions, 10 deletions
diff --git a/doc/README.commands b/doc/README.commands
index afd5577b0a9..1d29c4d91dd 100644
--- a/doc/README.commands
+++ b/doc/README.commands
@@ -1,19 +1,83 @@
+Command definition
+------------------
Commands are added to U-Boot by creating a new command structure.
-This is done by first including command.h, then using the U_BOOT_CMD() macro
-to fill in a cmd_tbl_t struct.
+This is done by first including command.h, then using the U_BOOT_CMD() or the
+U_BOOT_CMD_COMPLETE macro to fill in a cmd_tbl_t struct.
-U_BOOT_CMD(name,maxargs,repeatable,command,"usage","help")
+U_BOOT_CMD(name, maxargs, repeatable, command, "usage", "help")
+U_BOOT_CMD_COMPLETE(name, maxargs, repeatable, command, "usage, "help", comp)
-name: is the name of the commad. THIS IS NOT a string.
-maxargs: the maximum number of arguments this function takes
-repeatable: either 0 or 1 to indicate if autorepeat is allowed
-command: Function pointer (*cmd)(struct cmd_tbl_s *, int, int, char *[]);
-usage: Short description. This is a string
-help: Long description. This is a string
+name: The name of the command. THIS IS NOT a string.
+maxargs: The maximum number of arguments this function takes including
+ the command itself.
-**** Behind the scene ******
+repeatable: Either 0 or 1 to indicate if autorepeat is allowed.
+
+command: Pointer to the command function. This is the function that is
+ called when the command is issued.
+
+usage: Short description. This is a string.
+
+help: Long description. This is a string. The long description is
+ only available if CONFIG_SYS_LONGHELP is defined.
+
+comp: Pointer to the completion function. May be NULL.
+ This function is called if the user hits the TAB key while
+ entering the command arguments to complete the entry. Command
+ completion is only available if CONFIG_AUTO_COMPLETE is defined.
+
+Command function
+----------------
+
+The commmand function pointer has to be of type
+int (*cmd)(struct cmd_tbl_s *cmdtp, int flag, int argc, const char *argv[]);
+
+cmdtp: Table entry describing the command (see above).
+
+flag: A bitmap which may contain the following bit:
+ CMD_FLAG_REPEAT - The last command is repeated.
+ CMD_FLAG_BOOTD - The command is called by the bootd command.
+ CMD_FLAG_ENV - The command is called by the run command.
+
+argc: Number of arguments including the command.
+
+argv: Arguments.
+
+Allowable return value are:
+
+CMD_SUCCESS The command was successfully executed.
+
+CMD_FAILURE The command failed.
+
+CMD_RET_USAGE The command was called with invalid parameters. This value
+ leads to the display of the usage string.
+
+Completion function
+-------------------
+
+The completion function pointer has to be of type
+int (*complete)(int argc, char *const argv[], char last_char,
+ int maxv, char *cmdv[]);
+
+argc: Number of arguments including the command.
+
+argv: Arguments.
+
+last_char: The last character in the command line buffer.
+
+maxv: Maximum number of possible completions that may be returned by
+ the function.
+
+cmdv: Used to return possible values for the last argument. The last
+ possible completion must be followed by NULL.
+
+The function returns the number of possible completions (without the terminating
+NULL value).
+
+Behind the scene
+----------------
The structure created is named with a special prefix and placed by
the linker in a special section using the linker lists mechanism