diff options
| -rw-r--r-- | drivers/base/core.c | 58 |
1 files changed, 57 insertions, 1 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 1107d03aa6b3..4cc030361165 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1506,6 +1506,53 @@ static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode) } /** + * 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. + */ +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_INFERRED) == + (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) + continue; + + if (!fw_devlink_relax_cycle(link->consumer, sup)) + continue; + + ret = 1; + + if (!(link->flags & DL_FLAG_INFERRED)) + continue; + + pm_runtime_drop_link(link); + link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE; + dev_dbg(link->consumer, "Relaxing link with %s\n", + dev_name(link->supplier)); + } + return ret; +} + +/** * 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 @@ -1536,8 +1583,17 @@ static int fw_devlink_create_devlink(struct device *con, * 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)) + 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); ret = -EINVAL; + } goto out; } |