of: property: Update implementation of add_links() to create fwnode links

The semantics of add_links() has changed from creating device link
between devices to creating fwnode links between fwnodes. So, update the
implementation of add_links() to match the new semantics.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-15-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 408a7b5..620d29f 100644 (file)
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1038,33 +1038,9 @@ 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
+ * of_link_to_phandle - Add fwnode link to supplier from supplier phandle
+ * @con_np: consumer device tree node
+ * @sup_np: supplier device tree node
  *
  * Given a phandle to a supplier device tree node (@sup_np), this function
  * finds the device that owns the supplier device tree node and creates a
@@ -1074,16 +1050,14 @@ static struct device *of_get_next_parent_dev(struct device_node *np)
  * cases, it returns an error.
  *
  * Returns:
- * - 0 if link successfully created to supplier
- * - -EAGAIN if linking to the supplier should be reattempted
+ * - 0 if fwnode link successfully created to supplier
  * - -EINVAL if the supplier link is invalid and should not be created
- * - -ENODEV if there is no device that corresponds to the supplier phandle
+ * - -ENODEV if struct device will never be create for supplier
  */
-static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
-                             u32 dl_flags)
+static int of_link_to_phandle(struct device_node *con_np,
+                             struct device_node *sup_np)
 {
-       struct device *sup_dev, *sup_par_dev;
-       int ret = 0;
+       struct device *sup_dev;
        struct device_node *tmp_np = sup_np;
 
        of_node_get(sup_np);
@@ -1106,7 +1080,8 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
        }
 
        if (!sup_np) {
-               dev_dbg(dev, "Not linking to %pOFP - No device\n", tmp_np);
+               pr_debug("Not linking %pOFP to %pOFP - No device\n",
+                        con_np, tmp_np);
                return -ENODEV;
        }
 
@@ -1115,53 +1090,30 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
         * descendant nodes. By definition, a child node can't be a functional
         * dependency for the parent node.
         */
-       if (of_is_ancestor_of(dev->of_node, sup_np)) {
-               dev_dbg(dev, "Not linking to %pOFP - is descendant\n", sup_np);
+       if (of_is_ancestor_of(con_np, sup_np)) {
+               pr_debug("Not linking %pOFP to %pOFP - is descendant\n",
+                        con_np, sup_np);
                of_node_put(sup_np);
                return -EINVAL;
        }
+
+       /*
+        * Don't create links to "early devices" that won't have struct devices
+        * created for them.
+        */
        sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
        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);
+               pr_debug("Not linking %pOFP to %pOFP - No struct device\n",
+                        con_np, sup_np);
                of_node_put(sup_np);
                return -ENODEV;
-       } else if (!sup_dev) {
-               /*
-                * 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);
-
-               if (sup_par_dev && device_is_dependent(dev, sup_par_dev)) {
-                       /* Cyclic dependency detected, don't try to link */
-                       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 = -EINVAL;
        put_device(sup_dev);
-       return ret;
+
+       fwnode_link_add(of_fwnode_handle(con_np), of_fwnode_handle(sup_np));
+       of_node_put(sup_np);
+
+       return 0;
 }
 
 /**
@@ -1361,37 +1313,29 @@ static const struct supplier_bindings of_supplier_bindings[] = {
  * that list phandles to suppliers. If @prop_name isn't one, this function
  * doesn't do anything.
  *
- * If @prop_name is one, this function attempts to create device links from the
- * consumer device @dev to all the devices of the suppliers listed in
- * @prop_name.
+ * If @prop_name is one, this function attempts to create fwnode links from the
+ * consumer device tree node @con_np to all the suppliers device tree nodes
+ * listed in @prop_name.
  *
- * Any failed attempt to create a device link will NOT result in an immediate
+ * Any failed attempt to create a fwnode link will NOT result in an immediate
  * return.  of_link_property() must create links to all the available supplier
- * devices even when attempts to create a link to one or more suppliers fail.
+ * device tree nodes even when attempts to create a link to one or more
+ * suppliers fail.
  */
-static int of_link_property(struct device *dev, struct device_node *con_np,
-                            const char *prop_name)
+static int of_link_property(struct device_node *con_np, const char *prop_name)
 {
        struct device_node *phandle;
        const struct supplier_bindings *s = of_supplier_bindings;
        unsigned int i = 0;
        bool matched = false;
        int ret = 0;
-       u32 dl_flags;
-
-       if (dev->of_node == con_np)
-               dl_flags = fw_devlink_get_flags();
-       else
-               dl_flags = DL_FLAG_SYNC_STATE_ONLY;
 
        /* Do not stop at first failed link, link all available suppliers. */
        while (!matched && s->parse_prop) {
                while ((phandle = s->parse_prop(con_np, prop_name, i))) {
                        matched = true;
                        i++;
-                       if (of_link_to_phandle(dev, phandle, dl_flags)
-                                                               == -EAGAIN)
-                               ret = -EAGAIN;
+                       of_link_to_phandle(con_np, phandle);
                        of_node_put(phandle);
                }
                s++;
@@ -1399,31 +1343,19 @@ static int of_link_property(struct device *dev, struct device_node *con_np,
        return ret;
 }
 
-static int of_link_to_suppliers(struct device *dev,
-                                 struct device_node *con_np)
+static int of_fwnode_add_links(struct fwnode_handle *fwnode,
+                              struct device *dev)
 {
-       struct device_node *child;
        struct property *p;
-       int ret = 0;
+       struct device_node *con_np = to_of_node(fwnode);
 
-       for_each_property_of_node(con_np, p)
-               if (of_link_property(dev, con_np, p->name))
-                       ret = -ENODEV;
-
-       for_each_available_child_of_node(con_np, child)
-               if (of_link_to_suppliers(dev, child) && !ret)
-                       ret = -EAGAIN;
-
-       return ret;
-}
+       if (!con_np)
+               return -EINVAL;
 
-static int of_fwnode_add_links(const struct fwnode_handle *fwnode,
-                              struct device *dev)
-{
-       if (unlikely(!is_of_node(fwnode)))
-               return 0;
+       for_each_property_of_node(con_np, p)
+               of_link_property(con_np, p->name);
 
-       return of_link_to_suppliers(dev, to_of_node(fwnode));
+       return 0;
 }
 
 const struct fwnode_operations of_fwnode_ops = {