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

diff --git a/src/jtag/core.c b/src/jtag/core.c
index 0cec11ad35134abc429c282b70aff583c42066de..a8d65f1e59000ddf21d42a1f9a0fad55a41cf706 100644 (file)
--- a/src/jtag/core.c
+++ b/src/jtag/core.c
@@ -61,6 +61,8 @@ static int jtag_error = ERROR_OK;
 static const char *jtag_event_strings[] =
 {
        [JTAG_TRST_ASSERTED] = "JTAG controller reset (RESET or TRST)",
+       [JTAG_TAP_EVENT_ENABLE] = "TAP enabled",
+       [JTAG_TAP_EVENT_DISABLE] = "TAP disabled",
 };
 
 static int jtag_trst = 0;

diff --git a/src/jtag/jtag.h b/src/jtag/jtag.h
index 956343eea4a6099c85fa2180532f3dcee344b2a2..cddceef4a061fa86733df98d9feb57bb2c4a1a2b 100644 (file)
--- a/src/jtag/jtag.h
+++ b/src/jtag/jtag.h
@@ -201,19 +201,18 @@ extern unsigned jtag_tap_count(void);
  * - SRST pulls TRST
  * - TRST asserted
  *
- **/
+ * TAP activation/deactivation is currently implemented outside the core
+ * using scripted code that understands the specific router type.
+ */
 enum jtag_event {
-       JTAG_TRST_ASSERTED
-};
-
-enum jtag_tap_event {
+       JTAG_TRST_ASSERTED,
        JTAG_TAP_EVENT_ENABLE,
-       JTAG_TAP_EVENT_DISABLE
+       JTAG_TAP_EVENT_DISABLE,
 };
 
 struct jtag_tap_event_action_s
 {
-       enum jtag_tap_event      event;
+       enum jtag_event         event;
        Jim_Obj*                 body;
        jtag_tap_event_action_t* next;
 };

diff --git a/src/jtag/tcl.c b/src/jtag/tcl.c
index aa55809fb4f515134b7e22e96b7c4bb8f720a9ce..ec74a9e17bd29ecc40a4d6e559ba0975ba2b8854 100644 (file)
--- a/src/jtag/tcl.c
+++ b/src/jtag/tcl.c
@@ -256,7 +256,7 @@ static int jtag_tap_configure_cmd( Jim_GetOptInfo *goi, jtag_tap_t * tap)
                                        jteap = tap->event_action;
                                        /* replace existing? */
                                        while (jteap) {
-                                               if (jteap->event == (enum jtag_tap_event)n->value) {
+                                               if (jteap->event == (enum jtag_event)n->value) {
                                                        break;
                                                }
                                                jteap = jteap->next;
@@ -460,7 +460,7 @@ static int jim_newtap_cmd( Jim_GetOptInfo *goi )
        return JIM_ERR;
 }
 
-static void jtag_tap_handle_event( jtag_tap_t * tap, enum jtag_tap_event e)
+static void jtag_tap_handle_event(jtag_tap_t *tap, enum jtag_event e)
 {
        jtag_tap_event_action_t * jteap;
        int done;
@@ -594,6 +594,8 @@ static int jim_jtag_command( Jim_Interp *interp, int argc, Jim_Obj *const *argv
                                 *  - scan chain length grew by one (this)
                                 *  - IDs and IR lengths are as expected
                                 */
+
+                               jtag_call_event_callbacks(JTAG_TAP_EVENT_ENABLE);
                                break;
                        case JTAG_CMD_TAPDISABLE:
                                if (!t->enabled)
@@ -606,6 +608,8 @@ static int jim_jtag_command( Jim_Interp *interp, int argc, Jim_Obj *const *argv
                                 *  - scan chain length shrank by one (this)
                                 *  - IDs and IR lengths are as expected
                                 */
+
+                               jtag_call_event_callbacks(JTAG_TAP_EVENT_DISABLE);
                                break;
                        }
                        e = t->enabled;

diff --git a/src/target/target.c b/src/target/target.c
index d0227247096c23c8b322c0780ac6c71719a62e0a..32e46b2759d11fc69369867cc05e714b7bbdefe9 100644 (file)
--- 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;
        }