cortex_a/r/m: fix handling of un-examined cores

On multi-core systems, with some cores in power-down state, examination
will fail for these cores. Make sure assert- and deassert_reset functions
don't crash due to uninitialized variables.

Change-Id: I472f8d19af2cd3c770c05f3e57a31b35a863b687
Signed-off-by: Matthias Welwarsky <matthias.welwarsky@sysgo.com>
Reviewed-on: http://openocd.zylin.com/3552
Tested-by: jenkins
Reviewed-by: Jiri Kastner <cz172638@gmail.com>
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>

src/target/cortex_a.c

@@ -853,7 +853,8 @@ static int cortex_a_halt_smp(struct target *target)
 	head = target->head;
 	while (head != (struct target_list *)NULL) {
 		curr = head->target;
-		if ((curr != target) && (curr->state != TARGET_HALTED))
+		if ((curr != target) && (curr->state != TARGET_HALTED)
+			&& target_was_examined(curr))
 			retval += cortex_a_halt(curr);
 		head = head->next;
 	}
@@ -1156,7 +1157,8 @@ static int cortex_a_restore_smp(struct target *target, int handle_breakpoints)
 	head = target->head;
 	while (head != (struct target_list *)NULL) {
 		curr = head->target;
-		if ((curr != target) && (curr->state != TARGET_RUNNING)) {
+		if ((curr != target) && (curr->state != TARGET_RUNNING)
+			&& target_was_examined(curr)) {
 			/*  resume current address , not in step mode */
 			retval += cortex_a_internal_restore(curr, 1, &address,
 					handle_breakpoints, 0);
@@ -1936,7 +1938,8 @@ static int cortex_a_assert_reset(struct target *target)
 	}
 
 	/* registers are now invalid */
-	register_cache_invalidate(armv7a->arm.core_cache);
+	if (target_was_examined(target))
+		register_cache_invalidate(armv7a->arm.core_cache);
 
 	target->state = TARGET_RESET;
 
@@ -1952,17 +1955,22 @@ static int cortex_a_deassert_reset(struct target *target)
 	/* be certain SRST is off */
 	jtag_add_reset(0, 0);
 
-	retval = cortex_a_poll(target);
-	if (retval != ERROR_OK)
-		return retval;
+	if (target_was_examined(target)) {
+		retval = cortex_a_poll(target);
+		if (retval != ERROR_OK)
+			return retval;
+	}
 
 	if (target->reset_halt) {
 		if (target->state != TARGET_HALTED) {
 			LOG_WARNING("%s: ran after reset and before halt ...",
 				target_name(target));
-			retval = target_halt(target);
-			if (retval != ERROR_OK)
-				return retval;
+			if (target_was_examined(target)) {
+				retval = target_halt(target);
+				if (retval != ERROR_OK)
+					return retval;
+			} else
+				target->state = TARGET_UNKNOWN;
 		}
 	}
 

src/target/cortex_m.c

@@ -981,6 +981,18 @@ static int cortex_m_assert_reset(struct target *target)
 
 	bool srst_asserted = false;
 
+	if (!target_was_examined(target)) {
+		if (jtag_reset_config & RESET_HAS_SRST) {
+			adapter_assert_reset();
+			if (target->reset_halt)
+				LOG_ERROR("Target not examined, will not halt after reset!");
+			return ERROR_OK;
+		} else {
+			LOG_ERROR("Target not examined, reset NOT asserted!");
+			return ERROR_FAIL;
+		}
+	}
+
 	if ((jtag_reset_config & RESET_HAS_SRST) &&
 	    (jtag_reset_config & RESET_SRST_NO_GATING)) {
 		adapter_assert_reset();
@@ -1101,7 +1113,8 @@ static int cortex_m_deassert_reset(struct target *target)
 	enum reset_types jtag_reset_config = jtag_get_reset_config();
 
 	if ((jtag_reset_config & RESET_HAS_SRST) &&
-	    !(jtag_reset_config & RESET_SRST_NO_GATING)) {
+	    !(jtag_reset_config & RESET_SRST_NO_GATING) &&
+		target_was_examined(target)) {
 		int retval = dap_dp_init(armv7m->debug_ap->dap);
 		if (retval != ERROR_OK) {
 			LOG_ERROR("DP initialisation failed");