target/cortex_m: drop useless target_halt() call

In 2008 the commit 182936125371 ("define resetting
the target into the halted or running state as an atomic operation.")
introduced the target_halt() call to the end of cortex_m3_assert_reset(),

Checkpatch-ignore: GIT_COMMIT_ID

A year later the commit ed36a8d15dfd
("... Updated halt handling for cortex_m3")
prevented cortex_m3_halt() take any action in case of TARGET_RESET state.
This narrowed the target_halt() called from cortex_m3_assert_reset()
to setting target->halt_issued and storing a time stamp.

Introducing ocd_process_reset(_inner) made the setting of halt_issued
and halt_issued_time useless. The Tcl function waits for halt
of all targets if applicable.

cortex_m_halt() and also target_halt() does not work as expected
if the cached target state is TARGET_RESET (although the core could
be out of reset and ready to be halted, just have not been polled).
Explicit Tcl arp_poll must be issued in many scenarios.

Remove the useless hack.

Also remove the explicit error return from cortex_m_halt_one()
in case of RESET_SRST_PULLS_TRST and asserted srst. If the communication
with the target is gated by any reset, cortex_m_write_debug_halt_mask()
fails. Propagate the error return of this call instead.

Change-Id: I0da05b87f43c3d0facb78e54d8f00c1728fe7c46
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: https://review.openocd.org/c/openocd/+/8098
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

1 files changed, 4 insertions, 27 deletions

diff --git a/src/target/cortex_m.c b/src/target/cortex_m.c
index 8bb852f..fb1794a 100644
--- a/src/target/cortex_m.c
+++ b/src/target/cortex_m.c
@@ -1106,6 +1106,7 @@ static int cortex_m_poll(struct target *target)
 
 static int cortex_m_halt_one(struct target *target)
 {
+	int retval;
 	LOG_TARGET_DEBUG(target, "target->state: %s", target_state_name(target));
 
 	if (target->state == TARGET_HALTED) {
@@ -1116,22 +1117,8 @@ static int cortex_m_halt_one(struct target *target)
 	if (target->state == TARGET_UNKNOWN)
 		LOG_TARGET_WARNING(target, "target was in unknown state when halt was requested");
 
-	if (target->state == TARGET_RESET) {
-		if ((jtag_get_reset_config() & RESET_SRST_PULLS_TRST) && jtag_get_srst()) {
-			LOG_TARGET_ERROR(target, "can't request a halt while in reset if nSRST pulls nTRST");
-			return ERROR_TARGET_FAILURE;
-		} else {
-			/* we came here in a reset_halt or reset_init sequence
-			 * debug entry was already prepared in cortex_m3_assert_reset()
-			 */
-			target->debug_reason = DBG_REASON_DBGRQ;
-
-			return ERROR_OK;
-		}
-	}
-
 	/* Write to Debug Halting Control and Status Register */
-	cortex_m_write_debug_halt_mask(target, C_HALT, 0);
+	retval = cortex_m_write_debug_halt_mask(target, C_HALT, 0);
 
 	/* Do this really early to minimize the window where the MASKINTS erratum
 	 * can pile up pending interrupts. */
@@ -1139,7 +1126,7 @@ static int cortex_m_halt_one(struct target *target)
 
 	target->debug_reason = DBG_REASON_DBGRQ;
 
-	return ERROR_OK;
+	return retval;
 }
 
 static int cortex_m_halt(struct target *target)
@@ -1755,17 +1742,7 @@ static int cortex_m_assert_reset(struct target *target)
 
 	register_cache_invalidate(cortex_m->armv7m.arm.core_cache);
 
-	/* now return stored error code if any */
-	if (retval != ERROR_OK)
-		return retval;
-
-	if (target->reset_halt && target_was_examined(target)) {
-		retval = target_halt(target);
-		if (retval != ERROR_OK)
-			return retval;
-	}
-
-	return ERROR_OK;
+	return retval;
 }
 
 static int cortex_m_deassert_reset(struct target *target)