diff options
Diffstat (limited to 'drivers/of/dynamic.c')
| -rw-r--r-- | drivers/of/dynamic.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c new file mode 100644 index 000000000000..125994330437 --- /dev/null +++ b/drivers/of/dynamic.c @@ -0,0 +1,216 @@ +/* + * Support for dynamic device trees. + * + * On some platforms, the device tree can be manipulated at runtime. + * The routines in this section support adding, removing and changing + * device tree nodes. + */ + +#include <linux/of.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/proc_fs.h> + +#include "of_private.h" + +/** + * of_node_get() - Increment refcount of a node + * @node: Node to inc refcount, NULL is supported to simplify writing of + * callers + * + * Returns node. + */ +struct device_node *of_node_get(struct device_node *node) +{ + if (node) + kobject_get(&node->kobj); + return node; +} +EXPORT_SYMBOL(of_node_get); + +/** + * of_node_put() - Decrement refcount of a node + * @node: Node to dec refcount, NULL is supported to simplify writing of + * callers + */ +void of_node_put(struct device_node *node) +{ + if (node) + kobject_put(&node->kobj); +} +EXPORT_SYMBOL(of_node_put); + +static void of_node_remove(struct device_node *np) +{ + struct property *pp; + + BUG_ON(!of_node_is_initialized(np)); + + /* only remove properties if on sysfs */ + if (of_node_is_attached(np)) { + for_each_property_of_node(np, pp) + sysfs_remove_bin_file(&np->kobj, &pp->attr); + kobject_del(&np->kobj); + } + + /* finally remove the kobj_init ref */ + of_node_put(np); +} + +static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain); + +int of_reconfig_notifier_register(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&of_reconfig_chain, nb); +} +EXPORT_SYMBOL_GPL(of_reconfig_notifier_register); + +int of_reconfig_notifier_unregister(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&of_reconfig_chain, nb); +} +EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister); + +int of_reconfig_notify(unsigned long action, void *p) +{ + int rc; + + rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p); + return notifier_to_errno(rc); +} + +int of_property_notify(int action, struct device_node *np, + struct property *prop) +{ + struct of_prop_reconfig pr; + + /* only call notifiers if the node is attached */ + if (!of_node_is_attached(np)) + return 0; + + pr.dn = np; + pr.prop = prop; + return of_reconfig_notify(action, &pr); +} + +/** + * of_attach_node() - Plug a device node into the tree and global list. + */ +int of_attach_node(struct device_node *np) +{ + unsigned long flags; + int rc; + + rc = of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np); + if (rc) + return rc; + + raw_spin_lock_irqsave(&devtree_lock, flags); + np->sibling = np->parent->child; + np->allnext = np->parent->allnext; + np->parent->allnext = np; + np->parent->child = np; + of_node_clear_flag(np, OF_DETACHED); + raw_spin_unlock_irqrestore(&devtree_lock, flags); + + of_node_add(np); + return 0; +} + +/** + * of_detach_node() - "Unplug" a node from the device tree. + * + * The caller must hold a reference to the node. The memory associated with + * the node is not freed until its refcount goes to zero. + */ +int of_detach_node(struct device_node *np) +{ + struct device_node *parent; + unsigned long flags; + int rc = 0; + + rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np); + if (rc) + return rc; + + raw_spin_lock_irqsave(&devtree_lock, flags); + + if (of_node_check_flag(np, OF_DETACHED)) { + /* someone already detached it */ + raw_spin_unlock_irqrestore(&devtree_lock, flags); + return rc; + } + + parent = np->parent; + if (!parent) { + raw_spin_unlock_irqrestore(&devtree_lock, flags); + return rc; + } + + if (of_allnodes == np) + of_allnodes = np->allnext; + else { + struct device_node *prev; + for (prev = of_allnodes; + prev->allnext != np; + prev = prev->allnext) + ; + prev->allnext = np->allnext; + } + + if (parent->child == np) + parent->child = np->sibling; + else { + struct device_node *prevsib; + for (prevsib = np->parent->child; + prevsib->sibling != np; + prevsib = prevsib->sibling) + ; + prevsib->sibling = np->sibling; + } + + of_node_set_flag(np, OF_DETACHED); + raw_spin_unlock_irqrestore(&devtree_lock, flags); + + of_node_remove(np); + return rc; +} + +/** + * of_node_release() - release a dynamically allocated node + * @kref: kref element of the node to be released + * + * In of_node_put() this function is passed to kref_put() as the destructor. + */ +void of_node_release(struct kobject *kobj) +{ + struct device_node *node = kobj_to_device_node(kobj); + struct property *prop = node->properties; + + /* We should never be releasing nodes that haven't been detached. */ + if (!of_node_check_flag(node, OF_DETACHED)) { + pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name); + dump_stack(); + return; + } + + if (!of_node_check_flag(node, OF_DYNAMIC)) + return; + + while (prop) { + struct property *next = prop->next; + kfree(prop->name); + kfree(prop->value); + kfree(prop); + prop = next; + + if (!prop) { + prop = node->deadprops; + node->deadprops = NULL; + } + } + kfree(node->full_name); + kfree(node->data); + kfree(node); +} |