X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=doc%2FREADME.commands;h=1d29c4d91dddf9b1552f8b8f26aa5596a94f9077;hb=d99894dd3a713ea6226ac39a7e332b55cf8aca49;hp=125f077c08ffc03f7cf549e6c54480e3a6a41b87;hpb=2d1d65838eacd314b989701bd2f9e2b657bbf62b;p=u-boot

diff --git a/doc/README.commands b/doc/README.commands
index 125f077c08..1d29c4d91d 100644
--- a/doc/README.commands
+++ b/doc/README.commands
@@ -1,38 +1,100 @@
+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.
 
-The structure created is named with a special prefix (__u_boot_cmd_)
-and placed by the linker in a special section.
+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
+(see include/linker_lists.h)
 
 This makes it possible for the final link to extract all commands
 compiled into any object code and construct a static array so the
-command can be found in an array starting at __u_boot_cmd_start.
+command array can be iterated over using the linker lists macros.
 
-To ensure that the linker does not discard these symbols when linking
-full U-Boot we generate a list of all the commands we have built (based
-on the sections mentioned above) and use that to force the linker to
-first enter the symbol as undefined in the output object so that there
-is then a need for the symbol to be kept (this is the UNDEF_SYM logic in
-the Makefile).
+The linker lists feature ensures that the linker does not discard
+these symbols when linking full U-Boot even though they are not
+referenced in the source code as such.
 
 If a new board is defined do not forget to define the command section
-by writing in u-boot.lds ($(TOPDIR)/board/boardname/u-boot.lds) these
+by writing in u-boot.lds ($(srctree)/board/boardname/u-boot.lds) these
 3 lines:
 
-	__u_boot_cmd_start = .;
-	.u_boot_cmd : { *(.u_boot_cmd) }
-	__u_boot_cmd_end = .;
+	.u_boot_list : {
+		KEEP(*(SORT(.u_boot_list*)));
+	}