4 files changed, 45 insertions, 108 deletions

diff --git a/util/sconfig/main.c b/util/sconfig/main.c
index dd26e07de8..533c9fbb18 100644
--- a/util/sconfig/main.c
+++ b/util/sconfig/main.c
@@ -81,7 +81,6 @@ static struct device override_root_dev;
 static struct chip_instance mainboard_instance;
 
 static struct bus base_root_bus = {
-	.id = 0,
 	.dev = &base_root_dev,
 };
 
@@ -95,7 +94,6 @@ static struct device base_root_dev = {
 };
 
 static struct bus chipset_root_bus = {
-	.id = 0,
 	.dev = &chipset_root_dev,
 };
 
@@ -109,7 +107,6 @@ static struct device chipset_root_dev = {
 };
 
 static struct bus override_root_bus = {
-	.id = 0,
 	.dev = &override_root_dev,
 };
 
@@ -723,30 +720,13 @@ void add_device_ops(struct bus *bus, char *ops_id)
 	bus->dev->ops_id = ops_id;
 }
 
-/*
- * Allocate a new bus for the provided device.
- *   - If this is the first bus being allocated under this device, then its id
- *     is set to 0 and bus and last_bus are pointed to the newly allocated bus.
- *   - If this is not the first bus under this device, then its id is set to 1
- *     plus the id of last bus and newly allocated bus is added to the list of
- *     buses under the device. last_bus is updated to point to the newly
- *     allocated bus.
- */
+/* Allocate a new bus for the provided device. */
 static void alloc_bus(struct device *dev)
 {
 	struct bus *bus = S_ALLOC(sizeof(*bus));
 
 	bus->dev = dev;
-
-	if (dev->last_bus == NULL)  {
-		bus->id = 0;
-		dev->bus = bus;
-	} else {
-		bus->id = dev->last_bus->id + 1;
-		dev->last_bus->next_bus = bus;
-	}
-
-	dev->last_bus = bus;
+	dev->bus = bus;
 }
 
 /*
@@ -814,14 +794,15 @@ static const struct device *find_alias(const struct device *const parent,
 	if (parent->alias && !strcmp(parent->alias, alias))
 		return parent;
 
-	const struct bus *bus;
-	for (bus = parent->bus; bus; bus = bus->next_bus) {
-		const struct device *child;
-		for (child = bus->children; child; child = child->sibling) {
-			const struct device *const ret = find_alias(child, alias);
-			if (ret)
-				return ret;
-		}
+	const struct bus *bus = parent->bus;
+	if (!bus)
+		return NULL;
+
+	const struct device *child;
+	for (child = bus->children; child; child = child->sibling) {
+		const struct device *const ret = find_alias(child, alias);
+		if (ret)
+			return ret;
 	}
 
 	return NULL;
@@ -834,11 +815,11 @@ static struct device *new_device_with_path(struct bus *parent,
 {
 	struct device *new_d;
 
-	/* If device is found under parent, no need to allocate new device. */
+	/* We don't allow duplicate devices in devicetree. */
 	new_d = get_dev(parent, path_a, path_b, bustype, chip_instance);
 	if (new_d) {
-		alloc_bus(new_d);
-		return new_d;
+		printf("ERROR: Duplicate device! %s\n", new_d->name);
+		exit(1);
 	}
 
 	new_d = alloc_dev(parent);
@@ -1084,11 +1065,8 @@ static int dev_has_children(struct device *dev)
 {
 	struct bus *bus = dev->bus;
 
-	while (bus) {
-		if (bus->children)
-			return 1;
-		bus = bus->next_bus;
-	}
+	if (bus && bus->children)
+		return 1;
 
 	return 0;
 }
@@ -1098,7 +1076,7 @@ static void pass0(FILE *fil, FILE *head, struct device *ptr, struct device *next
 	static int dev_id;
 
 	if (ptr == &base_root_dev) {
-		fprintf(fil, "STORAGE struct bus %s_links[];\n",
+		fprintf(fil, "STORAGE struct bus %s_bus;\n",
 			ptr->name);
 		return;
 	}
@@ -1120,7 +1098,7 @@ static void pass0(FILE *fil, FILE *head, struct device *ptr, struct device *next
 		fprintf(fil, "STORAGE struct resource %s_res[];\n",
 			ptr->name);
 	if (dev_has_children(ptr))
-		fprintf(fil, "STORAGE struct bus %s_links[];\n",
+		fprintf(fil, "STORAGE struct bus %s_bus;\n",
 			ptr->name);
 
 	if (next)
@@ -1192,35 +1170,18 @@ static void emit_resources(FILE *fil, struct device *ptr)
 	fprintf(fil, "\t };\n");
 }
 
-static void emit_bus(FILE *fil, struct bus *bus)
+static void emit_dev_bus(FILE *fil, struct device *ptr)
 {
-	fprintf(fil, "\t\t[%d] = {\n", bus->id);
-	fprintf(fil, "\t\t\t.link_num = %d,\n", bus->id);
-	fprintf(fil, "\t\t\t.dev = &%s,\n", bus->dev->name);
-	if (bus->children)
-		fprintf(fil, "\t\t\t.children = &%s,\n", bus->children->name);
-
-	if (bus->next_bus)
-		fprintf(fil, "\t\t\t.next=&%s_links[%d],\n", bus->dev->name,
-			bus->id + 1);
-	else
-		fprintf(fil, "\t\t\t.next = NULL,\n");
-	fprintf(fil, "\t\t},\n");
-}
-
-static void emit_dev_links(FILE *fil, struct device *ptr)
-{
-	fprintf(fil, "STORAGE struct bus %s_links[] = {\n",
+	fprintf(fil, "STORAGE struct bus %s_bus = {\n",
 		ptr->name);
 
+	assert(ptr->bus && ptr->bus->children);
 	struct bus *bus = ptr->bus;
 
-	while (bus) {
-		emit_bus(fil, bus);
-		bus = bus->next_bus;
-	}
+	fprintf(fil, "\t.dev = &%s,\n", bus->dev->name);
+	fprintf(fil, "\t.children = &%s,\n", bus->children->name);
 
-	fprintf(fil, "\t};\n");
+	fprintf(fil, "};\n");
 }
 
 static struct chip_instance *get_chip_instance(const struct device *dev)
@@ -1268,8 +1229,7 @@ static void pass1(FILE *fil, FILE *head, struct device *ptr, struct device *next
 	else
 		fprintf(fil, "\t.ops = NULL,\n");
 	fprintf(fil, "#endif\n");
-	fprintf(fil, "\t.bus = &%s_links[%d],\n", ptr->parent->dev->name,
-		ptr->parent->id);
+	fprintf(fil, "\t.bus = &%s_bus,\n", ptr->parent->dev->name);
 	fprintf(fil, "\t.path = {");
 	fprintf(fil, ptr->path, ptr->path_a, ptr->path_b);
 	fprintf(fil, "},\n");
@@ -1290,7 +1250,7 @@ static void pass1(FILE *fil, FILE *head, struct device *ptr, struct device *next
 			ptr->name);
 	}
 	if (has_children)
-		fprintf(fil, "\t.link_list = &%s_links[0],\n",
+		fprintf(fil, "\t.link_list = &%s_bus,\n",
 			ptr->name);
 	else
 		fprintf(fil, "\t.link_list = NULL,\n");
@@ -1319,7 +1279,7 @@ static void pass1(FILE *fil, FILE *head, struct device *ptr, struct device *next
 	emit_resources(fil, ptr);
 
 	if (has_children)
-		emit_dev_links(fil, ptr);
+		emit_dev_bus(fil, ptr);
 }
 
 static void expose_device_names(FILE *fil, FILE *head, struct device *ptr, struct device *next)
@@ -1370,11 +1330,8 @@ static void add_children_to_queue(struct queue_entry **bfs_q_head,
 {
 	struct bus *bus = d->bus;
 
-	while (bus) {
-		if (bus->children)
-			add_siblings_to_queue(bfs_q_head, bus->children);
-		bus = bus->next_bus;
-	}
+	if (dev_has_children(d))
+		add_siblings_to_queue(bfs_q_head, bus->children);
 }
 
 static void walk_device_tree(FILE *fil, FILE *head, struct device *ptr,
@@ -1724,12 +1681,9 @@ static void override_devicetree(struct bus *base_parent,
  * +-----------------------------------------------------------------+
  * |                    |                                            |
  * | bus                | Recursively call override_devicetree on    |
- * | last_bus           | each bus of override device. It is assumed |
+ * |                    | each bus of override device. It is assumed |
  * |                    | that bus with id X under base device       |
- * |                    | to bus with id X under override device. If |
- * |                    | override device has more buses than base   |
- * |                    | device, then new buses are allocated under |
- * |                    | base device.                               |
+ * |                    | to bus with id X under override device.    |
  * |                    |                                            |
  * +-----------------------------------------------------------------+
  */
@@ -1841,29 +1795,20 @@ static void update_device(struct device *base_dev, struct device *override_dev)
 	/*
 	 * Now that the device properties are all copied over, look at each bus
 	 * of the override device and run override_devicetree in a recursive
-	 * manner. The assumption here is that first bus of override device
-	 * corresponds to first bus of base device and so on. If base device has
-	 * lesser buses than override tree, then new buses are allocated for it.
+	 * manner. If base device has no bus but the override tree has, then a new
+	 * bus is allocated for it.
 	 */
 	struct bus *override_bus = override_dev->bus;
 	struct bus *base_bus = base_dev->bus;
 
-	while (override_bus) {
-
-		/*
-		 * If we have more buses in override tree device, then allocate
-		 * a new bus for the base tree device as well.
-		 */
-		if (!base_bus) {
-			alloc_bus(base_dev);
-			base_bus = base_dev->last_bus;
-		}
-
-		override_devicetree(base_dev->bus, override_dev->bus);
+	/*
+	 * If we have more buses in override tree device, then allocate
+	 * a new bus for the base tree device as well.
+	 */
+	if (!base_bus)
+		alloc_bus(base_dev);
 
-		override_bus = override_bus->next_bus;
-		base_bus = base_bus->next_bus;
-	}
+	override_devicetree(base_dev->bus, override_dev->bus);
 }
 
 /*
diff --git a/util/sconfig/sconfig.h b/util/sconfig/sconfig.h
index cb8f7b36ef..bb9a98f268 100644
--- a/util/sconfig/sconfig.h
+++ b/util/sconfig/sconfig.h
@@ -106,17 +106,11 @@ struct chip {
 
 struct device;
 struct bus {
-	/* Instance/ID of the bus under the device. */
-	int id;
-
 	/* Pointer to device to which this bus belongs. */
 	struct device *dev;
 
 	/* Pointer to list of children. */
 	struct device *children;
-
-	/* Pointer to next bus for the device. */
-	struct bus *next_bus;
 };
 
 struct device {
@@ -157,10 +151,8 @@ struct device {
 	/* Pointer to chip instance for this device. */
 	struct chip_instance *chip_instance;
 
-	/* Pointer to list of buses under this device. */
+	/* Pointer to the bus under this device. */
 	struct bus *bus;
-	/* Pointer to last bus under this device. */
-	struct bus *last_bus;
 
 	/* Global identifier of the ops for this device. */
 	char *ops_id;
diff --git a/util/sconfig/sconfig.tab.c_shipped b/util/sconfig/sconfig.tab.c_shipped
index cb60fb59a7..5b10922a89 100644
--- a/util/sconfig/sconfig.tab.c_shipped
+++ b/util/sconfig/sconfig.tab.c_shipped
@@ -1238,7 +1238,7 @@ yyreduce:
   case 26: /* @2: %empty  */
                                                        {
 	(yyval.dev) = new_device_raw(cur_parent, cur_chip_instance, (yyvsp[-3].number), (yyvsp[-2].string), (yyvsp[-1].string), (yyvsp[0].number));
-	cur_parent = (yyval.dev)->last_bus;
+	cur_parent = (yyval.dev)->bus;
 }
     break;
 
@@ -1251,7 +1251,7 @@ yyreduce:
   case 28: /* @3: %empty  */
                                        {
 	(yyval.dev) = new_device_reference(cur_parent, cur_chip_instance, (yyvsp[-1].string), (yyvsp[0].number));
-	cur_parent = (yyval.dev)->last_bus;
+	cur_parent = (yyval.dev)->bus;
 }
     break;
 
diff --git a/util/sconfig/sconfig.y b/util/sconfig/sconfig.y
index 17ab9a5839..8ec103c018 100644
--- a/util/sconfig/sconfig.y
+++ b/util/sconfig/sconfig.y
@@ -44,7 +44,7 @@ chip: CHIP STRING /* == path */ {
 
 device: DEVICE BUS NUMBER /* == devnum */ alias status {
 	$<dev>$ = new_device_raw(cur_parent, cur_chip_instance, $<number>2, $<string>3, $<string>4, $<number>5);
-	cur_parent = $<dev>$->last_bus;
+	cur_parent = $<dev>$->bus;
 }
 	devicechildren END {
 	cur_parent = $<dev>6->parent;
@@ -52,7 +52,7 @@ device: DEVICE BUS NUMBER /* == devnum */ alias status {
 
 device: DEVICE REFERENCE STRING status {
 	$<dev>$ = new_device_reference(cur_parent, cur_chip_instance, $<string>3, $<number>4);
-	cur_parent = $<dev>$->last_bus;
+	cur_parent = $<dev>$->bus;
 }
 	devicechildren END {
 	cur_parent = $<dev>5->parent;