target/cortex_m: fix cortex_m reset_config help and check for syntax error

Remove option 'srst' which is not recognized from on-line help and texi.
Check parameter and return syntax error if wrong option is entered.

Change-Id: I87daa423a9f53193a0b015080594820b933628f5
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/4795
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

2 files changed, 11 insertions, 8 deletions

diff --git a/doc/openocd.texi b/doc/openocd.texi
index bc24aed..aa901e6 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -3458,6 +3458,7 @@ How long (in milliseconds) OpenOCD should wait after deasserting
 nTRST (active-low JTAG TAP reset) before starting new JTAG operations.
 @end deffn
 
+@anchor {reset_config}
 @deffn {Command} reset_config mode_flag ...
 This command displays or modifies the reset configuration
 of your combination of JTAG board and target in target
@@ -8994,13 +8995,13 @@ must also be explicitly enabled.
 This finishes by listing the current vector catch configuration.
 @end deffn
 
-@deffn Command {cortex_m reset_config} (@option{srst}|@option{sysresetreq}|@option{vectreset})
-Control reset handling. The default @option{srst} is to use srst if fitted,
-otherwise fallback to @option{vectreset}.
+@deffn Command {cortex_m reset_config} (@option{sysresetreq}|@option{vectreset})
+Control reset handling if hardware srst is not fitted
+@xref{reset_config,,reset_config}.
+
 @itemize @minus
-@item @option{srst} use hardware srst if fitted otherwise fallback to @option{vectreset}.
-@item @option{sysresetreq} use NVIC SYSRESETREQ to reset system.
-@item @option{vectreset} use NVIC VECTRESET to reset system.
+@item @option{sysresetreq} use AIRCR SYSRESETREQ to reset system.
+@item @option{vectreset} use AIRCR VECTRESET to reset system (default).
 @end itemize
 
 Using @option{vectreset} is a safe option for Cortex-M3, M4 and M7 cores.
diff --git a/src/target/cortex_m.c b/src/target/cortex_m.c
index bb8c06d..4ce776c 100644
--- a/src/target/cortex_m.c
+++ b/src/target/cortex_m.c
@@ -2436,7 +2436,9 @@ COMMAND_HANDLER(handle_cortex_m_reset_config_command)
 				LOG_WARNING("VECTRESET is not supported on your Cortex-M core!");
 			else
 				cortex_m->soft_reset_config = CORTEX_M_RESET_VECTRESET;
-		}
+
+		} else
+			return ERROR_COMMAND_SYNTAX_ERROR;
 	}
 
 	switch (cortex_m->soft_reset_config) {
@@ -2478,7 +2480,7 @@ static const struct command_registration cortex_m_exec_command_handlers[] = {
 		.handler = handle_cortex_m_reset_config_command,
 		.mode = COMMAND_ANY,
 		.help = "configure software reset handling",
-		.usage = "['srst'|'sysresetreq'|'vectreset']",
+		.usage = "['sysresetreq'|'vectreset']",
 	},
 	COMMAND_REGISTRATION_DONE
 };