Change jtag_add_pathmove to set jtag_error rather than call exit():

- Add new error codes to encode the possible failure conditions.
- Add documentation to describe the routine's possible error codes.


git-svn-id: svn://svn.berlios.de/openocd/trunk@2138 b42882b7-edfa-0310-969c-e2dbd0fdcd60

src/jtag/jtag.c

@@ -613,7 +613,8 @@ void jtag_add_pathmove(int num_states, const tap_state_t *path)
 	if (!tap_is_state_stable(path[num_states - 1]))
 	{
 		LOG_ERROR("BUG: TAP path doesn't finish in a stable state");
-		exit(-1);
+		jtag_set_error(ERROR_JTAG_NOT_STABLE_STATE);
+		return;
 	}
 
 	for (int i = 0; i < num_states; i++)
@@ -621,7 +622,8 @@ void jtag_add_pathmove(int num_states, const tap_state_t *path)
 		if (path[i] == TAP_RESET)
 		{
 			LOG_ERROR("BUG: TAP_RESET is not a valid state for pathmove sequences");
-			exit(-1);
+			jtag_set_error(ERROR_JTAG_STATE_INVALID);
+			return;
 		}
 
 		if ( tap_state_transition(cur_state, true)  != path[i]
@@ -629,7 +631,8 @@ void jtag_add_pathmove(int num_states, const tap_state_t *path)
 		{
 			LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition",
 					tap_state_name(cur_state), tap_state_name(path[i]));
-			exit(-1);
+			jtag_set_error(ERROR_JTAG_TRANSITION_INVALID);
+			return;
 		}
 		cur_state = path[i];
 	}

src/jtag/jtag.h

@@ -447,6 +447,12 @@ extern void jtag_add_tlr(void);
  * can only implement a few transitions and therefore
  * a partial implementation of pathmove would have little practical
  * application.
+ *
+ * If an error occurs, jtag_error will contain one of these error codes:
+ *   - ERROR_JTAG_NOT_STABLE_STATE -- The final state was not stable.
+ *   - ERROR_JTAG_STATE_INVALID -- The path passed through TAP_RESET.
+ *   - ERROR_JTAG_TRANSITION_INVALID -- The path includes invalid
+ *     state transitions.
  */
 extern void jtag_add_pathmove(int num_states, const tap_state_t* path);
 
@@ -606,6 +612,8 @@ void jtag_tap_handle_event(jtag_tap_t* tap, enum jtag_tap_event e);
 #define ERROR_JTAG_QUEUE_FAILED      (-104)
 #define ERROR_JTAG_NOT_STABLE_STATE  (-105)
 #define ERROR_JTAG_DEVICE_ERROR      (-107)
+#define ERROR_JTAG_STATE_INVALID     (-108)
+#define ERROR_JTAG_TRANSITION_INVALID (-109)
 
 /**
  * jtag_add_dr_out() is a version of jtag_add_dr_scan() which