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

Tighten error handling on TAP enable/disable paths a bit:

 - Don't enable/disable unless it's necessary.  Those event
   handlers could have nasty side effects...

 - Don't *succeed* enables/disables if there was no code which
   could have implemented that action.  This prevents bugs like
   wrongly acting as if the scan chain changed.

 - Minor whitespace cleanup in enable/disable command code.

The big problem is still the lack of code to verify scan chains
were actually updated as requested; this adds a comment on that.
I suspect the best we can do near term will be to verify IDCODE.

git-svn-id: svn://svn.berlios.de/openocd/trunk@2250 b42882b7-edfa-0310-969c-e2dbd0fdcd60

diff --git a/src/jtag/tcl.c b/src/jtag/tcl.c
index 0457bc70e0d4d2f7240e959b095aeaccd032513c..aa55809fb4f515134b7e22e96b7c4bb8f720a9ce 100644 (file)
--- a/src/jtag/tcl.c
+++ b/src/jtag/tcl.c
@@ -478,6 +478,12 @@ static void jtag_tap_handle_event( jtag_tap_t * tap, enum jtag_tap_event e)
                                        Jim_GetString(jteap->body, NULL) );
                        if (Jim_EvalObj(interp, jteap->body) != JIM_OK) {
                                Jim_PrintErrorMessage(interp);
+                       } else {
+                               /* NOTE:  we currently assume the handlers
+                                * can't fail.  That presumes later code
+                                * will be verifying the scan chains ...
+                                */
+                               tap->enabled = (e == JTAG_TAP_EVENT_ENABLE);
                        }
                }
 
@@ -569,26 +575,41 @@ static int jim_jtag_command( Jim_Interp *interp, int argc, Jim_Obj *const *argv
 
                {
                        jtag_tap_t *t;
-                       t = jtag_tap_by_jim_obj( goi.interp, goi.argv[0] );
-                       if( t == NULL ){
+
+                       t = jtag_tap_by_jim_obj(goi.interp, goi.argv[0]);
+                       if (t == NULL)
                                return JIM_ERR;
-                       }
-                       switch( n->value ){
+
+                       switch (n->value) {
                        case JTAG_CMD_TAPISENABLED:
-                               e = t->enabled;
                                break;
                        case JTAG_CMD_TAPENABLE:
-                               jtag_tap_handle_event( t, JTAG_TAP_EVENT_ENABLE);
-                               e = 1;
-                               t->enabled = e;
+                               if (t->enabled)
+                                       break;
+                               jtag_tap_handle_event(t, JTAG_TAP_EVENT_ENABLE);
+                               if (!t->enabled)
+                                       break;
+
+                               /* FIXME add JTAG sanity checks, w/o TLR
+                                *  - scan chain length grew by one (this)
+                                *  - IDs and IR lengths are as expected
+                                */
                                break;
                        case JTAG_CMD_TAPDISABLE:
-                               jtag_tap_handle_event( t, JTAG_TAP_EVENT_DISABLE);
-                               e = 0;
-                               t->enabled = e;
+                               if (!t->enabled)
+                                       break;
+                               jtag_tap_handle_event(t, JTAG_TAP_EVENT_DISABLE);
+                               if (t->enabled)
+                                       break;
+
+                               /* FIXME add JTAG sanity checks, w/o TLR
+                                *  - scan chain length shrank by one (this)
+                                *  - IDs and IR lengths are as expected
+                                */
                                break;
                        }
-                       Jim_SetResult( goi.interp, Jim_NewIntObj( goi.interp, e ) );
+                       e = t->enabled;
+                       Jim_SetResult(goi.interp, Jim_NewIntObj(goi.interp, e));
                        return JIM_OK;
                }
                break;