diff options
| -rw-r--r-- | drivers/of/property.c | 62 |
1 files changed, 56 insertions, 6 deletions
diff --git a/drivers/of/property.c b/drivers/of/property.c index b4916dcc9e72..0930f402a232 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -1015,6 +1015,30 @@ static bool of_is_ancestor_of(struct device_node *test_ancestor, } /** + * of_get_next_parent_dev - Add device link to supplier from supplier phandle + * @np: device tree node + * + * Given a device tree node (@np), this function finds its closest ancestor + * device tree node that has a corresponding struct device. + * + * The caller of this function is expected to call put_device() on the returned + * device when they are done. + */ +static struct device *of_get_next_parent_dev(struct device_node *np) +{ + struct device *dev = NULL; + + of_node_get(np); + do { + np = of_get_next_parent(np); + if (np) + dev = get_dev_from_fwnode(&np->fwnode); + } while (np && !dev); + of_node_put(np); + return dev; +} + +/** * of_link_to_phandle - Add device link to supplier from supplier phandle * @dev: consumer device * @sup_np: phandle to supplier device tree node @@ -1035,10 +1059,9 @@ static bool of_is_ancestor_of(struct device_node *test_ancestor, static int of_link_to_phandle(struct device *dev, struct device_node *sup_np, u32 dl_flags) { - struct device *sup_dev; + struct device *sup_dev, *sup_par_dev; int ret = 0; struct device_node *tmp_np = sup_np; - int is_populated; of_node_get(sup_np); /* @@ -1063,16 +1086,43 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np, return -EINVAL; } sup_dev = get_dev_from_fwnode(&sup_np->fwnode); - is_populated = of_node_check_flag(sup_np, OF_POPULATED); - of_node_put(sup_np); - if (!sup_dev && is_populated) { + if (!sup_dev && of_node_check_flag(sup_np, OF_POPULATED)) { /* Early device without struct device. */ dev_dbg(dev, "Not linking to %pOFP - No struct device\n", sup_np); + of_node_put(sup_np); return -ENODEV; } else if (!sup_dev) { - return -EAGAIN; + /* + * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports + * cycles. So cycle detection isn't necessary and shouldn't be + * done. + */ + if (dl_flags & DL_FLAG_SYNC_STATE_ONLY) { + of_node_put(sup_np); + return -EAGAIN; + } + + sup_par_dev = of_get_next_parent_dev(sup_np); + + /* Cyclic dependency detected, don't try to link */ + if (sup_par_dev && device_is_dependent(dev, sup_par_dev)) { + dev_dbg(dev, "Not linking to %pOFP - cycle detected\n", + sup_np); + ret = -EINVAL; + } else { + /* + * Can't check for cycles or no cycles. So let's try + * again later. + */ + ret = -EAGAIN; + } + + of_node_put(sup_np); + put_device(sup_par_dev); + return ret; } + of_node_put(sup_np); if (!device_link_add(dev, sup_dev, dl_flags)) ret = -EAGAIN; put_device(sup_dev); |