1 files changed, 319 insertions, 212 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index a3e14143ec0c..e54a10b5dbd7 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -54,11 +54,12 @@ static LIST_HEAD(deferred_sync);
 static unsigned int defer_sync_state_count = 1;
 static DEFINE_MUTEX(fwnode_link_lock);
 static bool fw_devlink_is_permissive(void);
+static void __fw_devlink_link_to_consumers(struct device *dev);
 static bool fw_devlink_drv_reg_done;
 static bool fw_devlink_best_effort;
 
 /**
- * fwnode_link_add - Create a link between two fwnode_handles.
+ * __fwnode_link_add - Create a link between two fwnode_handles.
  * @con: Consumer end of the link.
  * @sup: Supplier end of the link.
  *
@@ -74,35 +75,42 @@ static bool fw_devlink_best_effort;
  * Attempts to create duplicate links between the same pair of fwnode handles
  * are ignored and there is no reference counting.
  */
-int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
+static int __fwnode_link_add(struct fwnode_handle *con,
+			     struct fwnode_handle *sup, u8 flags)
 {
 	struct fwnode_link *link;
-	int ret = 0;
-
-	mutex_lock(&fwnode_link_lock);
 
 	list_for_each_entry(link, &sup->consumers, s_hook)
-		if (link->consumer == con)
-			goto out;
+		if (link->consumer == con) {
+			link->flags |= flags;
+			return 0;
+		}
 
 	link = kzalloc(sizeof(*link), GFP_KERNEL);
-	if (!link) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!link)
+		return -ENOMEM;
 
 	link->supplier = sup;
 	INIT_LIST_HEAD(&link->s_hook);
 	link->consumer = con;
 	INIT_LIST_HEAD(&link->c_hook);
+	link->flags = flags;
 
 	list_add(&link->s_hook, &sup->consumers);
 	list_add(&link->c_hook, &con->suppliers);
 	pr_debug("%pfwP Linked as a fwnode consumer to %pfwP\n",
 		 con, sup);
-out:
-	mutex_unlock(&fwnode_link_lock);
 
+	return 0;
+}
+
+int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
+{
+	int ret;
+
+	mutex_lock(&fwnode_link_lock);
+	ret = __fwnode_link_add(con, sup, 0);
+	mutex_unlock(&fwnode_link_lock);
 	return ret;
 }
 
@@ -122,6 +130,19 @@ static void __fwnode_link_del(struct fwnode_link *link)
 }
 
 /**
+ * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle.
+ * @link: the fwnode_link to be marked
+ *
+ * The fwnode_link_lock needs to be held when this function is called.
+ */
+static void __fwnode_link_cycle(struct fwnode_link *link)
+{
+	pr_debug("%pfwf: Relaxing link with %pfwf\n",
+		 link->consumer, link->supplier);
+	link->flags |= FWLINK_FLAG_CYCLE;
+}
+
+/**
  * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
  * @fwnode: fwnode whose supplier links need to be deleted
  *
@@ -181,7 +202,51 @@ void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
 }
 EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
 
-#ifdef CONFIG_SRCU
+/**
+ * __fwnode_links_move_consumers - Move consumer from @from to @to fwnode_handle
+ * @from: move consumers away from this fwnode
+ * @to: move consumers to this fwnode
+ *
+ * Move all consumer links from @from fwnode to @to fwnode.
+ */
+static void __fwnode_links_move_consumers(struct fwnode_handle *from,
+					  struct fwnode_handle *to)
+{
+	struct fwnode_link *link, *tmp;
+
+	list_for_each_entry_safe(link, tmp, &from->consumers, s_hook) {
+		__fwnode_link_add(link->consumer, to, link->flags);
+		__fwnode_link_del(link);
+	}
+}
+
+/**
+ * __fw_devlink_pickup_dangling_consumers - Pick up dangling consumers
+ * @fwnode: fwnode from which to pick up dangling consumers
+ * @new_sup: fwnode of new supplier
+ *
+ * If the @fwnode has a corresponding struct device and the device supports
+ * probing (that is, added to a bus), then we want to let fw_devlink create
+ * MANAGED device links to this device, so leave @fwnode and its descendant's
+ * fwnode links alone.
+ *
+ * Otherwise, move its consumers to the new supplier @new_sup.
+ */
+static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode,
+						   struct fwnode_handle *new_sup)
+{
+	struct fwnode_handle *child;
+
+	if (fwnode->dev && fwnode->dev->bus)
+		return;
+
+	fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
+	__fwnode_links_move_consumers(fwnode, new_sup);
+
+	fwnode_for_each_available_child_node(fwnode, child)
+		__fw_devlink_pickup_dangling_consumers(child, new_sup);
+}
+
 static DEFINE_MUTEX(device_links_lock);
 DEFINE_STATIC_SRCU(device_links_srcu);
 
@@ -220,47 +285,6 @@ static void device_link_remove_from_lists(struct device_link *link)
 	list_del_rcu(&link->s_node);
 	list_del_rcu(&link->c_node);
 }
-#else /* !CONFIG_SRCU */
-static DECLARE_RWSEM(device_links_lock);
-
-static inline void device_links_write_lock(void)
-{
-	down_write(&device_links_lock);
-}
-
-static inline void device_links_write_unlock(void)
-{
-	up_write(&device_links_lock);
-}
-
-int device_links_read_lock(void)
-{
-	down_read(&device_links_lock);
-	return 0;
-}
-
-void device_links_read_unlock(int not_used)
-{
-	up_read(&device_links_lock);
-}
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-int device_links_read_lock_held(void)
-{
-	return lockdep_is_held(&device_links_lock);
-}
-#endif
-
-static inline void device_link_synchronize_removal(void)
-{
-}
-
-static void device_link_remove_from_lists(struct device_link *link)
-{
-	list_del(&link->s_node);
-	list_del(&link->c_node);
-}
-#endif /* !CONFIG_SRCU */
 
 static bool device_is_ancestor(struct device *dev, struct device *target)
 {
@@ -272,6 +296,12 @@ static bool device_is_ancestor(struct device *dev, struct device *target)
 	return false;
 }
 
+static inline bool device_link_flag_is_sync_state_only(u32 flags)
+{
+	return (flags & ~(DL_FLAG_INFERRED | DL_FLAG_CYCLE)) ==
+		(DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED);
+}
+
 /**
  * device_is_dependent - Check if one device depends on another one
  * @dev: Device to check dependencies for.
@@ -298,8 +328,7 @@ int device_is_dependent(struct device *dev, void *target)
 		return ret;
 
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
-		if ((link->flags & ~DL_FLAG_INFERRED) ==
-		    (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
+		if (device_link_flag_is_sync_state_only(link->flags))
 			continue;
 
 		if (link->consumer == target)
@@ -372,8 +401,7 @@ static int device_reorder_to_tail(struct device *dev, void *not_used)
 
 	device_for_each_child(dev, NULL, device_reorder_to_tail);
 	list_for_each_entry(link, &dev->links.consumers, s_node) {
-		if ((link->flags & ~DL_FLAG_INFERRED) ==
-		    (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
+		if (device_link_flag_is_sync_state_only(link->flags))
 			continue;
 		device_reorder_to_tail(link->consumer, NULL);
 	}
@@ -634,7 +662,8 @@ postcore_initcall(devlink_class_init);
 			       DL_FLAG_AUTOREMOVE_SUPPLIER | \
 			       DL_FLAG_AUTOPROBE_CONSUMER  | \
 			       DL_FLAG_SYNC_STATE_ONLY | \
-			       DL_FLAG_INFERRED)
+			       DL_FLAG_INFERRED | \
+			       DL_FLAG_CYCLE)
 
 #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
 			    DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
@@ -703,8 +732,6 @@ struct device_link *device_link_add(struct device *consumer,
 	if (!consumer || !supplier || consumer == supplier ||
 	    flags & ~DL_ADD_VALID_FLAGS ||
 	    (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
-	    (flags & DL_FLAG_SYNC_STATE_ONLY &&
-	     (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
 	    (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
 	     flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
 		      DL_FLAG_AUTOREMOVE_SUPPLIER)))
@@ -720,6 +747,10 @@ struct device_link *device_link_add(struct device *consumer,
 	if (!(flags & DL_FLAG_STATELESS))
 		flags |= DL_FLAG_MANAGED;
 
+	if (flags & DL_FLAG_SYNC_STATE_ONLY &&
+	    !device_link_flag_is_sync_state_only(flags))
+		return NULL;
+
 	device_links_write_lock();
 	device_pm_lock();
 
@@ -984,6 +1015,21 @@ static bool dev_is_best_effort(struct device *dev)
 		(dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
 }
 
+static struct fwnode_handle *fwnode_links_check_suppliers(
+						struct fwnode_handle *fwnode)
+{
+	struct fwnode_link *link;
+
+	if (!fwnode || fw_devlink_is_permissive())
+		return NULL;
+
+	list_for_each_entry(link, &fwnode->suppliers, c_hook)
+		if (!(link->flags & FWLINK_FLAG_CYCLE))
+			return link->supplier;
+
+	return NULL;
+}
+
 /**
  * device_links_check_suppliers - Check presence of supplier drivers.
  * @dev: Consumer device.
@@ -1011,11 +1057,8 @@ int device_links_check_suppliers(struct device *dev)
 	 * probe.
 	 */
 	mutex_lock(&fwnode_link_lock);
-	if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
-	    !fw_devlink_is_permissive()) {
-		sup_fw = list_first_entry(&dev->fwnode->suppliers,
-					  struct fwnode_link,
-					  c_hook)->supplier;
+	sup_fw = fwnode_links_check_suppliers(dev->fwnode);
+	if (sup_fw) {
 		if (!dev_is_best_effort(dev)) {
 			fwnode_ret = -EPROBE_DEFER;
 			dev_err_probe(dev, -EPROBE_DEFER,
@@ -1204,7 +1247,9 @@ static ssize_t waiting_for_supplier_show(struct device *dev,
 	bool val;
 
 	device_lock(dev);
-	val = !list_empty(&dev->fwnode->suppliers);
+	mutex_lock(&fwnode_link_lock);
+	val = !!fwnode_links_check_suppliers(dev->fwnode);
+	mutex_unlock(&fwnode_link_lock);
 	device_unlock(dev);
 	return sysfs_emit(buf, "%u\n", val);
 }
@@ -1267,16 +1312,23 @@ void device_links_driver_bound(struct device *dev)
 	 * them. So, fw_devlink no longer needs to create device links to any
 	 * of the device's suppliers.
 	 *
-	 * Also, if a child firmware node of this bound device is not added as
-	 * a device by now, assume it is never going to be added and make sure
-	 * other devices don't defer probe indefinitely by waiting for such a
-	 * child device.
+	 * Also, if a child firmware node of this bound device is not added as a
+	 * device by now, assume it is never going to be added. Make this bound
+	 * device the fallback supplier to the dangling consumers of the child
+	 * firmware node because this bound device is probably implementing the
+	 * child firmware node functionality and we don't want the dangling
+	 * consumers to defer probe indefinitely waiting for a device for the
+	 * child firmware node.
 	 */
 	if (dev->fwnode && dev->fwnode->dev == dev) {
 		struct fwnode_handle *child;
 		fwnode_links_purge_suppliers(dev->fwnode);
+		mutex_lock(&fwnode_link_lock);
 		fwnode_for_each_available_child_node(dev->fwnode, child)
-			fw_devlink_purge_absent_suppliers(child);
+			__fw_devlink_pickup_dangling_consumers(child,
+							       dev->fwnode);
+		__fw_devlink_link_to_consumers(dev);
+		mutex_unlock(&fwnode_link_lock);
 	}
 	device_remove_file(dev, &dev_attr_waiting_for_supplier);
 
@@ -1633,8 +1685,11 @@ static int __init fw_devlink_strict_setup(char *arg)
 }
 early_param("fw_devlink.strict", fw_devlink_strict_setup);
 
-u32 fw_devlink_get_flags(void)
+static inline u32 fw_devlink_get_flags(u8 fwlink_flags)
 {
+	if (fwlink_flags & FWLINK_FLAG_CYCLE)
+		return FW_DEVLINK_FLAGS_PERMISSIVE | DL_FLAG_CYCLE;
+
 	return fw_devlink_flags;
 }
 
@@ -1672,7 +1727,7 @@ static void fw_devlink_relax_link(struct device_link *link)
 	if (!(link->flags & DL_FLAG_INFERRED))
 		return;
 
-	if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
+	if (device_link_flag_is_sync_state_only(link->flags))
 		return;
 
 	pm_runtime_drop_link(link);
@@ -1769,44 +1824,138 @@ static void fw_devlink_unblock_consumers(struct device *dev)
 	device_links_write_unlock();
 }
 
+
+static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
+{
+	struct device *dev;
+	bool ret;
+
+	if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED))
+		return false;
+
+	dev = get_dev_from_fwnode(fwnode);
+	ret = !dev || dev->links.status == DL_DEV_NO_DRIVER;
+	put_device(dev);
+
+	return ret;
+}
+
+static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
+{
+	struct fwnode_handle *parent;
+
+	fwnode_for_each_parent_node(fwnode, parent) {
+		if (fwnode_init_without_drv(parent)) {
+			fwnode_handle_put(parent);
+			return true;
+		}
+	}
+
+	return false;
+}
+
 /**
- * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
- * @con: Device to check dependencies for.
- * @sup: Device to check against.
- *
- * Check if @sup depends on @con or any device dependent on it (its child or
- * its consumer etc).  When such a cyclic dependency is found, convert all
- * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
- * This is the equivalent of doing fw_devlink=permissive just between the
- * devices in the cycle. We need to do this because, at this point, fw_devlink
- * can't tell which of these dependencies is not a real dependency.
- *
- * Return 1 if a cycle is found. Otherwise, return 0.
+ * __fw_devlink_relax_cycles - Relax and mark dependency cycles.
+ * @con: Potential consumer device.
+ * @sup_handle: Potential supplier's fwnode.
+ *
+ * Needs to be called with fwnode_lock and device link lock held.
+ *
+ * Check if @sup_handle or any of its ancestors or suppliers direct/indirectly
+ * depend on @con. This function can detect multiple cyles between @sup_handle
+ * and @con. When such dependency cycles are found, convert all device links
+ * created solely by fw_devlink into SYNC_STATE_ONLY device links. Also, mark
+ * all fwnode links in the cycle with FWLINK_FLAG_CYCLE so that when they are
+ * converted into a device link in the future, they are created as
+ * SYNC_STATE_ONLY device links. This is the equivalent of doing
+ * fw_devlink=permissive just between the devices in the cycle. We need to do
+ * this because, at this point, fw_devlink can't tell which of these
+ * dependencies is not a real dependency.
+ *
+ * Return true if one or more cycles were found. Otherwise, return false.
  */
-static int fw_devlink_relax_cycle(struct device *con, void *sup)
+static bool __fw_devlink_relax_cycles(struct device *con,
+				 struct fwnode_handle *sup_handle)
 {
-	struct device_link *link;
-	int ret;
+	struct device *sup_dev = NULL, *par_dev = NULL;
+	struct fwnode_link *link;
+	struct device_link *dev_link;
+	bool ret = false;
 
-	if (con == sup)
-		return 1;
+	if (!sup_handle)
+		return false;
 
-	ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
-	if (ret)
-		return ret;
+	/*
+	 * We aren't trying to find all cycles. Just a cycle between con and
+	 * sup_handle.
+	 */
+	if (sup_handle->flags & FWNODE_FLAG_VISITED)
+		return false;
 
-	list_for_each_entry(link, &con->links.consumers, s_node) {
-		if ((link->flags & ~DL_FLAG_INFERRED) ==
-		    (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
-			continue;
+	sup_handle->flags |= FWNODE_FLAG_VISITED;
 
-		if (!fw_devlink_relax_cycle(link->consumer, sup))
-			continue;
+	sup_dev = get_dev_from_fwnode(sup_handle);
 
-		ret = 1;
+	/* Termination condition. */
+	if (sup_dev == con) {
+		ret = true;
+		goto out;
+	}
 
-		fw_devlink_relax_link(link);
+	/*
+	 * If sup_dev is bound to a driver and @con hasn't started binding to a
+	 * driver, sup_dev can't be a consumer of @con. So, no need to check
+	 * further.
+	 */
+	if (sup_dev && sup_dev->links.status ==  DL_DEV_DRIVER_BOUND &&
+	    con->links.status == DL_DEV_NO_DRIVER) {
+		ret = false;
+		goto out;
+	}
+
+	list_for_each_entry(link, &sup_handle->suppliers, c_hook) {
+		if (__fw_devlink_relax_cycles(con, link->supplier)) {
+			__fwnode_link_cycle(link);
+			ret = true;
+		}
+	}
+
+	/*
+	 * Give priority to device parent over fwnode parent to account for any
+	 * quirks in how fwnodes are converted to devices.
+	 */
+	if (sup_dev)
+		par_dev = get_device(sup_dev->parent);
+	else
+		par_dev = fwnode_get_next_parent_dev(sup_handle);
+
+	if (par_dev && __fw_devlink_relax_cycles(con, par_dev->fwnode))
+		ret = true;
+
+	if (!sup_dev)
+		goto out;
+
+	list_for_each_entry(dev_link, &sup_dev->links.suppliers, c_node) {
+		/*
+		 * Ignore a SYNC_STATE_ONLY flag only if it wasn't marked as
+		 * such due to a cycle.
+		 */
+		if (device_link_flag_is_sync_state_only(dev_link->flags) &&
+		    !(dev_link->flags & DL_FLAG_CYCLE))
+			continue;
+
+		if (__fw_devlink_relax_cycles(con,
+					      dev_link->supplier->fwnode)) {
+			fw_devlink_relax_link(dev_link);
+			dev_link->flags |= DL_FLAG_CYCLE;
+			ret = true;
+		}
 	}
+
+out:
+	sup_handle->flags &= ~FWNODE_FLAG_VISITED;
+	put_device(sup_dev);
+	put_device(par_dev);
 	return ret;
 }
 
@@ -1814,7 +1963,7 @@ static int fw_devlink_relax_cycle(struct device *con, void *sup)
  * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
  * @con: consumer device for the device link
  * @sup_handle: fwnode handle of supplier
- * @flags: devlink flags
+ * @link: fwnode link that's being converted to a device link
  *
  * This function will try to create a device link between the consumer device
  * @con and the supplier device represented by @sup_handle.
@@ -1831,10 +1980,17 @@ static int fw_devlink_relax_cycle(struct device *con, void *sup)
  *  possible to do that in the future
  */
 static int fw_devlink_create_devlink(struct device *con,
-				     struct fwnode_handle *sup_handle, u32 flags)
+				     struct fwnode_handle *sup_handle,
+				     struct fwnode_link *link)
 {
 	struct device *sup_dev;
 	int ret = 0;
+	u32 flags;
+
+	if (con->fwnode == link->consumer)
+		flags = fw_devlink_get_flags(link->flags);
+	else
+		flags = FW_DEVLINK_FLAGS_PERMISSIVE;
 
 	/*
 	 * In some cases, a device P might also be a supplier to its child node
@@ -1855,7 +2011,26 @@ static int fw_devlink_create_devlink(struct device *con,
 	    fwnode_is_ancestor_of(sup_handle, con->fwnode))
 		return -EINVAL;
 
-	sup_dev = get_dev_from_fwnode(sup_handle);
+	/*
+	 * SYNC_STATE_ONLY device links don't block probing and supports cycles.
+	 * So cycle detection isn't necessary and shouldn't be done.
+	 */
+	if (!(flags & DL_FLAG_SYNC_STATE_ONLY)) {
+		device_links_write_lock();
+		if (__fw_devlink_relax_cycles(con, sup_handle)) {
+			__fwnode_link_cycle(link);
+			flags = fw_devlink_get_flags(link->flags);
+			dev_info(con, "Fixed dependency cycle(s) with %pfwf\n",
+				 sup_handle);
+		}
+		device_links_write_unlock();
+	}
+
+	if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)
+		sup_dev = fwnode_get_next_parent_dev(sup_handle);
+	else
+		sup_dev = get_dev_from_fwnode(sup_handle);
+
 	if (sup_dev) {
 		/*
 		 * If it's one of those drivers that don't actually bind to
@@ -1864,71 +2039,34 @@ static int fw_devlink_create_devlink(struct device *con,
 		 */
 		if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
 		    sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
+			dev_dbg(con,
+				"Not linking %pfwf - dev might never probe\n",
+				sup_handle);
 			ret = -EINVAL;
 			goto out;
 		}
 
-		/*
-		 * If this fails, it is due to cycles in device links.  Just
-		 * give up on this link and treat it as invalid.
-		 */
-		if (!device_link_add(con, sup_dev, flags) &&
-		    !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
-			dev_info(con, "Fixing up cyclic dependency with %s\n",
-				 dev_name(sup_dev));
-			device_links_write_lock();
-			fw_devlink_relax_cycle(con, sup_dev);
-			device_links_write_unlock();
-			device_link_add(con, sup_dev,
-					FW_DEVLINK_FLAGS_PERMISSIVE);
+		if (!device_link_add(con, sup_dev, flags)) {
+			dev_err(con, "Failed to create device link with %s\n",
+				dev_name(sup_dev));
 			ret = -EINVAL;
 		}
 
 		goto out;
 	}
 
-	/* Supplier that's already initialized without a struct device. */
-	if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
-		return -EINVAL;
-
 	/*
-	 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
-	 * cycles. So cycle detection isn't necessary and shouldn't be
-	 * done.
+	 * Supplier or supplier's ancestor already initialized without a struct
+	 * device or being probed by a driver.
 	 */
-	if (flags & DL_FLAG_SYNC_STATE_ONLY)
-		return -EAGAIN;
-
-	/*
-	 * If we can't find the supplier device from its fwnode, it might be
-	 * due to a cyclic dependency between fwnodes. Some of these cycles can
-	 * be broken by applying logic. Check for these types of cycles and
-	 * break them so that devices in the cycle probe properly.
-	 *
-	 * If the supplier's parent is dependent on the consumer, then the
-	 * consumer and supplier have a cyclic dependency. Since fw_devlink
-	 * can't tell which of the inferred dependencies are incorrect, don't
-	 * enforce probe ordering between any of the devices in this cyclic
-	 * dependency. Do this by relaxing all the fw_devlink device links in
-	 * this cycle and by treating the fwnode link between the consumer and
-	 * the supplier as an invalid dependency.
-	 */
-	sup_dev = fwnode_get_next_parent_dev(sup_handle);
-	if (sup_dev && device_is_dependent(con, sup_dev)) {
-		dev_info(con, "Fixing up cyclic dependency with %pfwP (%s)\n",
-			 sup_handle, dev_name(sup_dev));
-		device_links_write_lock();
-		fw_devlink_relax_cycle(con, sup_dev);
-		device_links_write_unlock();
-		ret = -EINVAL;
-	} else {
-		/*
-		 * Can't check for cycles or no cycles. So let's try
-		 * again later.
-		 */
-		ret = -EAGAIN;
+	if (fwnode_init_without_drv(sup_handle) ||
+	    fwnode_ancestor_init_without_drv(sup_handle)) {
+		dev_dbg(con, "Not linking %pfwf - might never become dev\n",
+			sup_handle);
+		return -EINVAL;
 	}
 
+	ret = -EAGAIN;
 out:
 	put_device(sup_dev);
 	return ret;
@@ -1956,7 +2094,6 @@ static void __fw_devlink_link_to_consumers(struct device *dev)
 	struct fwnode_link *link, *tmp;
 
 	list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
-		u32 dl_flags = fw_devlink_get_flags();
 		struct device *con_dev;
 		bool own_link = true;
 		int ret;
@@ -1986,14 +2123,13 @@ static void __fw_devlink_link_to_consumers(struct device *dev)
 				con_dev = NULL;
 			} else {
 				own_link = false;
-				dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
 			}
 		}
 
 		if (!con_dev)
 			continue;
 
-		ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
+		ret = fw_devlink_create_devlink(con_dev, fwnode, link);
 		put_device(con_dev);
 		if (!own_link || ret == -EAGAIN)
 			continue;
@@ -2013,10 +2149,7 @@ static void __fw_devlink_link_to_consumers(struct device *dev)
  *
  * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
  * and the real suppliers of @dev. Once these device links are created, the
- * fwnode links are deleted. When such device links are successfully created,
- * this function is called recursively on those supplier devices. This is
- * needed to detect and break some invalid cycles in fwnode links.  See
- * fw_devlink_create_devlink() for more details.
+ * fwnode links are deleted.
  *
  * In addition, it also looks at all the suppliers of the entire fwnode tree
  * because some of the child devices of @dev that have not been added yet
@@ -2034,44 +2167,16 @@ static void __fw_devlink_link_to_suppliers(struct device *dev,
 	bool own_link = (dev->fwnode == fwnode);
 	struct fwnode_link *link, *tmp;
 	struct fwnode_handle *child = NULL;
-	u32 dl_flags;
-
-	if (own_link)
-		dl_flags = fw_devlink_get_flags();
-	else
-		dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
 
 	list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
 		int ret;
-		struct device *sup_dev;
 		struct fwnode_handle *sup = link->supplier;
 
-		ret = fw_devlink_create_devlink(dev, sup, dl_flags);
+		ret = fw_devlink_create_devlink(dev, sup, link);
 		if (!own_link || ret == -EAGAIN)
 			continue;
 
 		__fwnode_link_del(link);
-
-		/* If no device link was created, nothing more to do. */
-		if (ret)
-			continue;
-
-		/*
-		 * If a device link was successfully created to a supplier, we
-		 * now need to try and link the supplier to all its suppliers.
-		 *
-		 * This is needed to detect and delete false dependencies in
-		 * fwnode links that haven't been converted to a device link
-		 * yet. See comments in fw_devlink_create_devlink() for more
-		 * details on the false dependency.
-		 *
-		 * Without deleting these false dependencies, some devices will
-		 * never probe because they'll keep waiting for their false
-		 * dependency fwnode links to be converted to device links.
-		 */
-		sup_dev = get_dev_from_fwnode(sup);
-		__fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
-		put_device(sup_dev);
 	}
 
 	/*
@@ -2354,7 +2459,7 @@ static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t
 		dev->class->get_ownership(dev, uid, gid);
 }
 
-static struct kobj_type device_ktype = {
+static const struct kobj_type device_ktype = {
 	.release	= device_release,
 	.sysfs_ops	= &dev_sysfs_ops,
 	.namespace	= device_namespace,
@@ -2387,9 +2492,9 @@ static const char *dev_uevent_name(const struct kobject *kobj)
 	return NULL;
 }
 
-static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env)
+static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
 {
-	struct device *dev = kobj_to_dev(kobj);
+	const struct device *dev = kobj_to_dev(kobj);
 	int retval = 0;
 
 	/* add device node properties if present */
@@ -2992,7 +3097,7 @@ struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *ko
 	return dir->class->ns_type;
 }
 
-static struct kobj_type class_dir_ktype = {
+static const struct kobj_type class_dir_ktype = {
 	.release	= class_dir_release,
 	.sysfs_ops	= &kobj_sysfs_ops,
 	.child_ns_type	= class_dir_child_ns_type
@@ -3026,8 +3131,9 @@ static DEFINE_MUTEX(gdp_mutex);
 static struct kobject *get_device_parent(struct device *dev,
 					 struct device *parent)
 {
+	struct kobject *kobj = NULL;
+
 	if (dev->class) {
-		struct kobject *kobj = NULL;
 		struct kobject *parent_kobj;
 		struct kobject *k;
 
@@ -3075,8 +3181,15 @@ static struct kobject *get_device_parent(struct device *dev,
 	}
 
 	/* subsystems can specify a default root directory for their devices */
-	if (!parent && dev->bus && dev->bus->dev_root)
-		return &dev->bus->dev_root->kobj;
+	if (!parent && dev->bus) {
+		struct device *dev_root = bus_get_dev_root(dev->bus);
+
+		if (dev_root) {
+			kobj = &dev_root->kobj;
+			put_device(dev_root);
+			return kobj;
+		}
+	}
 
 	if (parent)
 		return &parent->kobj;
@@ -3413,7 +3526,7 @@ int device_add(struct device *dev)
 	/* we require the name to be set before, and pass NULL */
 	error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
 	if (error) {
-		glue_dir = get_glue_dir(dev);
+		glue_dir = kobj;
 		goto Error;
 	}
 
@@ -3453,10 +3566,7 @@ int device_add(struct device *dev)
 	/* Notify clients of device addition.  This call must come
 	 * after dpm_sysfs_add() and before kobject_uevent().
 	 */
-	if (dev->bus)
-		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
-					     BUS_NOTIFY_ADD_DEVICE, dev);
-
+	bus_notify(dev, BUS_NOTIFY_ADD_DEVICE);
 	kobject_uevent(&dev->kobj, KOBJ_ADD);
 
 	/*
@@ -3513,6 +3623,7 @@ done:
 	device_pm_remove(dev);
 	dpm_sysfs_remove(dev);
  DPMError:
+	dev->driver = NULL;
 	bus_remove_device(dev);
  BusError:
 	device_remove_attrs(dev);
@@ -3636,9 +3747,7 @@ void device_del(struct device *dev)
 	 * before dpm_sysfs_remove().
 	 */
 	noio_flag = memalloc_noio_save();
-	if (dev->bus)
-		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
-					     BUS_NOTIFY_DEL_DEVICE, dev);
+	bus_notify(dev, BUS_NOTIFY_DEL_DEVICE);
 
 	dpm_sysfs_remove(dev);
 	if (parent)
@@ -3669,9 +3778,7 @@ void device_del(struct device *dev)
 	device_platform_notify_remove(dev);
 	device_links_purge(dev);
 
-	if (dev->bus)
-		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
-					     BUS_NOTIFY_REMOVED_DEVICE, dev);
+	bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE);
 	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
 	glue_dir = get_glue_dir(dev);
 	kobject_del(&dev->kobj);
@@ -3739,7 +3846,7 @@ static struct device *next_device(struct klist_iter *i)
  * a name. This memory is returned in tmp and needs to be
  * freed by the caller.
  */
-const char *device_get_devnode(struct device *dev,
+const char *device_get_devnode(const struct device *dev,
 			       umode_t *mode, kuid_t *uid, kgid_t *gid,
 			       const char **tmp)
 {