diff --git a/drivers/base/core.c b/drivers/base/core.c
index 0a8a5ab344c1564bbcff01833927c14d2604f355..2712a1a1e9590c7ea78776d0349e4a2f7a888c00 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1866,47 +1866,6 @@ static void fw_devlink_unblock_consumers(struct device *dev)
device_links_write_unlock();
}
-/**
- * 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.
- */
-static int fw_devlink_relax_cycle(struct device *con, void *sup)
-{
- struct device_link *link;
- int ret;
-
- if (con == sup)
- return 1;
-
- ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
- if (ret)
- return ret;
-
- list_for_each_entry(link, &con->links.consumers, s_node) {
- if (!(link->flags & DL_FLAG_CYCLE) &&
- device_link_flag_is_sync_state_only(link->flags))
- continue;
-
- if (!fw_devlink_relax_cycle(link->consumer, sup))
- continue;
-
- ret = 1;
-
- fw_devlink_relax_link(link);
- link->flags |= DL_FLAG_CYCLE;
- }
- return ret;
-}
static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
{
@@ -1937,6 +1896,111 @@ static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
return false;
}
+/**
+ * __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 bool __fw_devlink_relax_cycles(struct device *con,
+ struct fwnode_handle *sup_handle)
+{
+ struct device *sup_dev = NULL, *par_dev = NULL;
+ struct fwnode_link *link;
+ struct device_link *dev_link;
+ bool ret = false;
+
+ if (!sup_handle)
+ return false;
+
+ /*
+ * 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;
+
+ sup_handle->flags |= FWNODE_FLAG_VISITED;
+
+ sup_dev = get_dev_from_fwnode(sup_handle);
+
+ /* Termination condition. */
+ if (sup_dev == con) {
+ ret = true;
+ goto out;
+ }
+
+ /*
+ * 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;
+}
+
/**
* fw_devlink_create_devlink - Create a device link from a consumer to fwnode
* @con: consumer device for the device link
@@ -1989,6 +2053,21 @@ static int fw_devlink_create_devlink(struct device *con,
fwnode_is_ancestor_of(sup_handle, con->fwnode))
return -EINVAL;
+ /*
+ * 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
@@ -2002,23 +2081,16 @@ 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;
}
@@ -2031,49 +2103,12 @@ static int fw_devlink_create_devlink(struct device *con,
*/
if (fwnode_init_without_drv(sup_handle) ||
fwnode_ancestor_init_without_drv(sup_handle)) {
- dev_dbg(con, "Not linking %pfwP - Might never probe\n",
+ dev_dbg(con, "Not linking %pfwf - might never become dev\n",
sup_handle);
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.
- */
- 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;
- }
-
+ ret = -EAGAIN;
out:
put_device(sup_dev);
return ret;
@@ -2156,10 +2191,7 @@ 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
@@ -2180,7 +2212,6 @@ static void __fw_devlink_link_to_suppliers(struct device *dev,
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, link);
@@ -2188,27 +2219,6 @@ static void __fw_devlink_link_to_suppliers(struct device *dev,
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);
}
/*