David Brownell <david-b@pacbell.net>:

Extend the internal JTAG event handlers to cover enable/disable,
and use those events to make sure that targets get "examined" if
they were disabled when the scan chain was first set up:

 - Remove "enum jtag_tap_event", merge with "enum jtag_event",
   so C code can now listen for TAP enable/disable events.

 - Report those events so they can trigger callbacks.

 - During startup, make target_examine() register a handler to
   catch ENABLE events for any then-disabled targets.

This fixes bugs like "can't halt target after enabling its TAP".

One class of unresolved bugs:  if the target has an ETM hooked
up to an ETB, nothing activates the ETB.  But starting up the
ETM without access to the ETB registers fails...


git-svn-id: svn://svn.berlios.de/openocd/trunk@2251 b42882b7-edfa-0310-969c-e2dbd0fdcd60

1 files changed, 17 insertions, 1 deletions

diff --git a/src/target/target.c b/src/target/target.c
index d0227247..32e46b27 100644
--- a/src/target/target.c
+++ b/src/target/target.c
@@ -478,6 +478,18 @@ int target_examine_one(struct target_s *target)
 	return target->type->examine(target);
 }
 
+static int jtag_enable_callback(enum jtag_event event, void *priv)
+{
+	target_t *target = priv;
+
+	if (event != JTAG_TAP_EVENT_ENABLE || !target->tap->enabled)
+		return ERROR_OK;
+
+	jtag_unregister_event_callback(jtag_enable_callback, target);
+	return target_examine_one(target);
+}
+
+
 /* Targets that correctly implement init+examine, i.e.
  * no communication with target during init:
  *
@@ -490,8 +502,12 @@ int target_examine(void)
 
 	for (target = all_targets; target; target = target->next)
 	{
-		if (!target->tap->enabled)
+		/* defer examination, but don't skip it */
+		if (!target->tap->enabled) {
+			jtag_register_event_callback(jtag_enable_callback,
+					target);
 			continue;
+		}
 		if ((retval = target_examine_one(target)) != ERROR_OK)
 			return retval;
 	}