target: add examine-fail event

A configuration script may want to check the reason why examine fails
e.g. device has security lock engaged.

tcl/target/kx.cfg and klx.cfg is modified to use the new event
for testing of the security lock of Kinetis MCU

Change-Id: Id1d3a79d24e84b513f4ea35586cd2ab0437ff9b3
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/4289
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

doc/openocd.texi

@@ -4820,6 +4820,8 @@ The following target events are defined:
 @* Before target examine is called.
 @item @b{examine-end}
 @* After target examine is called with no errors.
+@item @b{examine-fail}
+@* After target examine fails.
 @item @b{gdb-attach}
 @* When GDB connects. Issued before any GDB communication with the target
 starts. GDB expects the target is halted during attachment.
@@ -5991,7 +5993,8 @@ Used in kinetis 'fcf_source protection' mode only.
 @end deffn
 
 @deffn Command {kinetis mdm check_security}
-Checks status of device security lock. Used internally in examine-end event.
+Checks status of device security lock. Used internally in examine-end
+and examine-fail event.
 @end deffn
 
 @deffn Command {kinetis mdm halt}

src/target/startup.tcl

@@ -66,7 +66,9 @@ proc ocd_process_reset_inner { MODE } {
 		if {![using_jtag] || [jtag tapisenabled [$t cget -chain-position]]} {
 			$t invoke-event examine-start
 			set err [catch "$t arp_examine allow-defer"]
-			if { $err == 0 } {
+			if { $err } {
+				$t invoke-event examine-fail
+			} else {
 				$t invoke-event examine-end
 			}
 		}

src/target/target.c

@@ -219,6 +219,7 @@ static const Jim_Nvp nvp_target_event[] = {
 	{ .value = TARGET_EVENT_RESET_END,           .name = "reset-end" },
 
 	{ .value = TARGET_EVENT_EXAMINE_START, .name = "examine-start" },
+	{ .value = TARGET_EVENT_EXAMINE_FAIL, .name = "examine-fail" },
 	{ .value = TARGET_EVENT_EXAMINE_END, .name = "examine-end" },
 
 	{ .value = TARGET_EVENT_DEBUG_HALTED, .name = "debug-halted" },
@@ -708,13 +709,17 @@ static int default_check_reset(struct target *target)
 	return ERROR_OK;
 }
 
+/* Equvivalent Tcl code arp_examine_one is in src/target/startup.tcl
+ * Keep in sync */
 int target_examine_one(struct target *target)
 {
 	target_call_event_callbacks(target, TARGET_EVENT_EXAMINE_START);
 
 	int retval = target->type->examine(target);
-	if (retval != ERROR_OK)
+	if (retval != ERROR_OK) {
+		target_call_event_callbacks(target, TARGET_EVENT_EXAMINE_FAIL);
 		return retval;
+	}
 
 	target_call_event_callbacks(target, TARGET_EVENT_EXAMINE_END);
 

src/target/target.h

@@ -275,6 +275,7 @@ enum target_event {
 	TARGET_EVENT_DEBUG_RESUMED, /* target resumed to execute on behalf of the debugger */
 
 	TARGET_EVENT_EXAMINE_START,
+	TARGET_EVENT_EXAMINE_FAIL,
 	TARGET_EVENT_EXAMINE_END,
 
 	TARGET_EVENT_GDB_ATTACH,

tcl/target/klx.cfg

@@ -56,9 +56,9 @@ if {[using_hla]} {
    echo " it without mass erase. Don't set write protection on the first block."
    echo "!!!!!!!!!!!!!!!!!!!!!! WARNING !!!!!!!!!!!!!!!!! WARNING !!!!!!!!!!!!!!!!!!!!!!"
    echo ""
-} {
-   # Detect secured MCU or boot lock-up in RESET/WDOG loop
-   $_CHIPNAME.cpu configure -event examine-start {
+} else {
+   # Detect secured MCU
+   $_TARGETNAME configure -event examine-fail {
       kinetis mdm check_security
    }
 

tcl/target/kx.cfg

@@ -58,9 +58,13 @@ if {[using_hla]} {
    echo " it without mass erase. Don't set write protection on the first block."
    echo "!!!!!!!!!!!!!!!!!!!!!! WARNING !!!!!!!!!!!!!!!!! WARNING !!!!!!!!!!!!!!!!!!!!!!"
    echo ""
-} {
+} else {
    # Detect secured MCU or boot lock-up in RESET/WDOG loop
-   $_CHIPNAME.cpu configure -event examine-start {
+   $_TARGETNAME configure -event examine-fail {
+      kinetis mdm check_security
+   }
+   # During RESET/WDOG loop the target is sometimes falsely examined
+   $_TARGETNAME configure -event examine-end {
       kinetis mdm check_security
    }