Cortex-A/R: Fix Mask-ISR parsing

Remove needless error when not halted with wrong return.
Allow usage in any mode
Add error message for incorrect arguments

Change-Id: I3e94e159609351e503ed3f35760503079e3aa53c
Signed-off-by: Evan Hunter <ehunter@broadcom.com>
Reviewed-on: http://openocd.zylin.com/3195
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>

src/target/cortex_a.c

@@ -3336,17 +3336,14 @@ COMMAND_HANDLER(handle_cortex_a_mask_interrupts_command)
 	};
 	const Jim_Nvp *n;
 
-	if (target->state != TARGET_HALTED) {
-		command_print(CMD_CTX, "target must be stopped for \"%s\" command", CMD_NAME);
-		return ERROR_OK;
-	}
-
 	if (CMD_ARGC > 0) {
 		n = Jim_Nvp_name2value_simple(nvp_maskisr_modes, CMD_ARGV[0]);
-		if (n->name == NULL)
+		if (n->name == NULL) {
+			LOG_ERROR("Unknown parameter: %s - should be off or on", CMD_ARGV[0]);
 			return ERROR_COMMAND_SYNTAX_ERROR;
-		cortex_a->isrmasking_mode = n->value;
+		}
 
+		cortex_a->isrmasking_mode = n->value;
 	}
 
 	n = Jim_Nvp_value2name_simple(nvp_maskisr_modes, cortex_a->isrmasking_mode);
@@ -3418,7 +3415,7 @@ static const struct command_registration cortex_a_exec_command_handlers[] = {
 	{
 		.name = "maskisr",
 		.handler = handle_cortex_a_mask_interrupts_command,
-		.mode = COMMAND_EXEC,
+		.mode = COMMAND_ANY,
 		.help = "mask cortex_a interrupts",
 		.usage = "['on'|'off']",
 	},