Extended the "maxwidth" DRC rule to take an optional set of layers

that exclude the maxwidth rule from taking effect.  This is
especially useful for implementing a maxwidth rule on top metal
that does not apply to pads, using the passivation cut layer to
prevent the maxwidth rule from being applied.

drc/DRCextend.c

@@ -449,6 +449,31 @@ drcCheckRectSize(starttile, arg, cptr)
     }
 }
 
+/*
+ *-------------------------------------------------------------------------
+ *
+ * MaxRectsExclude ---
+ *
+ *	Trivial callback function which detects if a type is found
+ *	overlapping a Maxrects area.
+ *
+ * Results:
+ *	Always return 1 to immediately halt the search.
+ *
+ * Side effects:
+ *	None.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+int
+MaxRectsExclude(
+    Tile *tile,
+    ClientData clientdata)
+{
+    return 1;
+}
+
 /*
  *-------------------------------------------------------------------------
  *
@@ -563,10 +588,31 @@ drcCanonicalMaxwidth(starttile, dir, arg, cptr)
     mrd->maxdist = edgelimit;
     TTMaskCom2(&wrongtypes, &cptr->drcc_mask);
     boundorig = *boundrect;
-    DBSrPaintArea(starttile, arg->dCD_celldef->cd_planes[cptr->drcc_plane],
+    DBSrPaintArea(starttile, arg->dCD_celldef->cd_planes[cptr->drcc_edgeplane],
 		&boundorig, &wrongtypes, FindMaxRects, mrd);
     if (mrd->entries == 0)
 	return NULL;
+    else if (cptr->drcc_plane != cptr->drcc_edgeplane)
+    {
+	/* If the "exclude" option is used, then the maxrect rule will be
+	 * ignored for any metal area partially or totally covered by any
+	 * type in cptr->drcc_corner on plane cptr->drcc_plane (!=
+	 * cptr->drcc_edgeplane).
+	 */
+	for (s = 0; s < mrd->entries; s++)
+	{
+	    Rect *r = &(mrd->rlist[s]);
+	    if (DBSrPaintArea((Tile *)NULL,
+			arg->dCD_celldef->cd_planes[cptr->drcc_plane],
+			r, &cptr->drcc_corner, MaxRectsExclude, NULL) != 0)
+	    {
+		/* Take this area out of consideration */
+		r->r_xtop = r->r_xbot;
+		r->r_ytop = r->r_ybot;
+	    }
+	}
+	return (MaxRectsData *)mrd;
+    }
     else
 	return (MaxRectsData *)mrd;
 }

drc/DRCtech.c

@@ -1061,7 +1061,7 @@ DRCTechAddRule(sectionName, argc, argv)
     "layers area horizon why"},
         {"off_grid",	 4,	4,	drcOffGrid,
     "layers pitch why"},
-        {"maxwidth",	 4,	5,	drcMaxwidth,
+        {"maxwidth",	 4,	6,	drcMaxwidth,
     "layers maxwidth bends why"},
 	{"cifstyle",	 2,	2,	drcCifSetStyle,
     "cif_style"},
@@ -1582,7 +1582,7 @@ drcOffGrid(argc, argv)
  * Process a maxwidth rule.
  * This is of the form:
  *
- *	maxwidth layers distance [bends] why
+ *	maxwidth layers distance [bends] [exclude_layers] why
  *
  * This routine was updated 3/6/05 to match the "canonical" definition of
  * a maxwidth region, which is any rectangle containing <layers> that is
@@ -1591,6 +1591,11 @@ drcOffGrid(argc, argv)
  * (see below) for backwards-compatibility.  Otherwise ("bend_ok" or
  * nothing), the new routine is used.
  *
+ * exclude_layers is optional and indicates a type or types (which if more
+ * than one must all be on the same plane) that prevent "maxwidth" from
+ * being checked.  A common use case is using "glass" (passivation cut) to
+ * exclude top metal on a pad from being checked for maximum metal width.
+ *
  *	maxwidth metal1 389 "metal1 width > 35um must be slotted"
  *	maxwidth pmc 4 bend_illegal "poly contact area must be no wider than 4"
  *	maxwidth trench 4 bend_ok "trench width must be exactly 4"
@@ -1629,11 +1634,11 @@ drcMaxwidth(argc, argv)
     int distance = atoi(argv[2]);
     char *bends = argv[3];
     int why;
-    TileTypeBitMask set, setC;
+    TileTypeBitMask set, setC, setE;
     DRCCookie *dp, *dpnew;
     TileType i, j;
-    PlaneMask pmask, ptest, pset;
-    int plane;
+    PlaneMask pmask, pmask2, ptest, pset;
+    int plane, plane2;
     int bend;
 
     ptest = DBTechNoisyNameMask(layers, &set);
@@ -1667,8 +1672,34 @@ drcMaxwidth(argc, argv)
 	    TechError("unknown bend option %s\n",bends);
 	    return (0);
 	}
-	why = drcWhyCreate(argv[4]);
+	if (argc == 6)
+	    why = drcWhyCreate(argv[5]);
+	else
+	    why = drcWhyCreate(argv[4]);
     }
+    if (argc == 6)
+    {
+	ptest = DBTechNoisyNameMask(argv[4], &setE);
+	pmask2 = CoincidentPlanes(&setE, ptest);
+	if (pmask2 == 0)
+	{
+	    TechError("All layers for \"maxwidth\" exclude types must "
+			"be on same plane.\n");
+	    return (0);
+	}
+	else
+	{
+	    for (plane2 = PL_TECHDEPBASE; plane2 < DBNumPlanes; plane2++)
+	        if (PlaneMaskHasPlane(pmask2, plane2))
+		    break;
+
+	    if (plane2 == plane)
+		TechError("Warning:  Exclude types for \"maxwidth\" are on the "
+			"same plane and so cannot be checked.\n");
+	}
+    }
+    else
+	plane2 = -1;
 
     for (i = 0; i < DBNumTypes; i++)
     {
@@ -1689,8 +1720,12 @@ drcMaxwidth(argc, argv)
 		    /* find bucket preceding the new one we wish to insert */
 		    dp = drcFindBucket(i, j, distance);
 		    dpnew = (DRCCookie *) mallocMagic(sizeof (DRCCookie));
-		    drcAssign(dpnew, distance, dp->drcc_next, &set, &set, why,
+		    if (plane2 == -1)
+			drcAssign(dpnew, distance, dp->drcc_next, &set, &set, why,
 				    distance, DRC_MAXWIDTH | bend, plane, plane);
+		    else
+			drcAssign(dpnew, distance, dp->drcc_next, &set, &setE, why,
+				    distance, DRC_MAXWIDTH | bend, plane2, plane);
 
 		    dp->drcc_next = dpnew;
 		}