From 9ab49135c639e6ed5e3997356b54c6cf79d04985 Mon Sep 17 00:00:00 2001
From: oharboe <oharboe@b42882b7-edfa-0310-969c-e2dbd0fdcd60>
Date: Thu, 4 Jun 2009 06:56:22 +0000
Subject: [PATCH] JTAG_TRST_ASSERTED event cleanup. More clear where and when
 it is invoked and some duplicate(harmless) invocations avoided.

git-svn-id: svn://svn.berlios.de/openocd/trunk@2040 b42882b7-edfa-0310-969c-e2dbd0fdcd60
---
 src/jtag/jtag.c | 14 ++++++--------
 src/jtag/jtag.h | 11 +++++++++++
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/jtag/jtag.c b/src/jtag/jtag.c
index fca603657f..0733789f1b 100644
--- a/src/jtag/jtag.c
+++ b/src/jtag/jtag.c
@@ -385,17 +385,14 @@ int jtag_call_event_callbacks(enum jtag_event event)
 	return ERROR_OK;
 }
 
-static void jtag_prelude1(void)
+static void jtag_checks(void)
 {
 	assert(jtag_trst == 0);
-
-	if (cmd_queue_end_state == TAP_RESET)
-		jtag_call_event_callbacks(JTAG_TRST_ASSERTED);
 }
 
 static void jtag_prelude(tap_state_t state)
 {
-	jtag_prelude1();
+	jtag_checks();
 
 	if (state != TAP_INVALID)
 		jtag_add_end_state(state);
@@ -596,6 +593,8 @@ void jtag_add_tlr(void)
 	retval=interface_jtag_add_tlr();
 	if (retval!=ERROR_OK)
 		jtag_error=retval;
+	
+	jtag_call_event_callbacks(JTAG_TRST_ASSERTED);
 }
 
 void jtag_add_pathmove(int num_states, const tap_state_t *path)
@@ -628,7 +627,7 @@ void jtag_add_pathmove(int num_states, const tap_state_t *path)
 		cur_state = path[i];
 	}
 
-	jtag_prelude1();
+	jtag_checks();
 
 	retval = interface_jtag_add_pathmove(num_states, path);
 	cmd_queue_cur_state = path[num_states - 1];
@@ -663,7 +662,7 @@ void jtag_add_clocks( int num_cycles )
 
 	if( num_cycles > 0 )
 	{
-		jtag_prelude1();
+		jtag_checks();
 
 		retval = interface_jtag_add_clocks(num_cycles);
 		if (retval != ERROR_OK)
@@ -755,7 +754,6 @@ void jtag_add_reset(int req_tlr_or_trst, int req_srst)
 		LOG_DEBUG("JTAG reset with RESET instead of TRST");
 		jtag_add_end_state(TAP_RESET);
 		jtag_add_tlr();
-		jtag_call_event_callbacks(JTAG_TRST_ASSERTED);
 		return;
 	}
 
diff --git a/src/jtag/jtag.h b/src/jtag/jtag.h
index 04eefaadb3..5fbe7dc103 100644
--- a/src/jtag/jtag.h
+++ b/src/jtag/jtag.h
@@ -218,6 +218,17 @@ enum reset_line_mode {
 	LINE_PUSH_PULL  = 0x1,
 };
 
+/* 
+ * There are three cases when JTAG_TRST_ASSERTED callback is invoked. The
+ * event is invoked *after* TRST is asserted(or queued rather). It is illegal 
+ * to communicate with the JTAG interface during the callback(as there is 
+ * currently a queue being built).
+ * 
+ * - TMS reset
+ * - SRST pulls TRST
+ * - TRST asserted
+ * 
+ **/
 enum jtag_event {
 	JTAG_TRST_ASSERTED
 };
-- 
2.30.2