![Grant Likely](/assets/img/avatar_default.png)
Split the dynamic device tree code into a separate file to make it really clear what features CONFIF_OF_DYNAMIC add to the kernel. Without CONFIG_OF_DYNAMIC only properties can be changed, and notifiers do not get sent. Enabling it turns on reference counting, notifiers and the ability to add and remove nodes. v2: Moved of_node_release() into dynamic.c Signed-off-by: Grant Likely <grant.likely@linaro.org> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com> Cc: Rob Herring <robh+dt@kernel.org>
217 lines
4.7 KiB
C
217 lines
4.7 KiB
C
/*
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* Support for dynamic device trees.
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*
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* On some platforms, the device tree can be manipulated at runtime.
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* The routines in this section support adding, removing and changing
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* device tree nodes.
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*/
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#include <linux/of.h>
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#include <linux/spinlock.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/proc_fs.h>
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#include "of_private.h"
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/**
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* of_node_get() - Increment refcount of a node
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* @node: Node to inc refcount, NULL is supported to simplify writing of
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* callers
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*
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* Returns node.
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*/
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struct device_node *of_node_get(struct device_node *node)
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{
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if (node)
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kobject_get(&node->kobj);
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return node;
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}
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EXPORT_SYMBOL(of_node_get);
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/**
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* of_node_put() - Decrement refcount of a node
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* @node: Node to dec refcount, NULL is supported to simplify writing of
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* callers
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*/
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void of_node_put(struct device_node *node)
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{
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if (node)
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kobject_put(&node->kobj);
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}
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EXPORT_SYMBOL(of_node_put);
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static void of_node_remove(struct device_node *np)
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{
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struct property *pp;
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BUG_ON(!of_node_is_initialized(np));
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/* only remove properties if on sysfs */
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if (of_node_is_attached(np)) {
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for_each_property_of_node(np, pp)
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sysfs_remove_bin_file(&np->kobj, &pp->attr);
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kobject_del(&np->kobj);
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}
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/* finally remove the kobj_init ref */
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of_node_put(np);
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}
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static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
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int of_reconfig_notifier_register(struct notifier_block *nb)
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{
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return blocking_notifier_chain_register(&of_reconfig_chain, nb);
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}
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EXPORT_SYMBOL_GPL(of_reconfig_notifier_register);
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int of_reconfig_notifier_unregister(struct notifier_block *nb)
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{
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return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
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}
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EXPORT_SYMBOL_GPL(of_reconfig_notifier_unregister);
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int of_reconfig_notify(unsigned long action, void *p)
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{
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int rc;
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rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
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return notifier_to_errno(rc);
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}
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int of_property_notify(int action, struct device_node *np,
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struct property *prop)
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{
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struct of_prop_reconfig pr;
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/* only call notifiers if the node is attached */
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if (!of_node_is_attached(np))
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return 0;
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pr.dn = np;
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pr.prop = prop;
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return of_reconfig_notify(action, &pr);
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}
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/**
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* of_attach_node() - Plug a device node into the tree and global list.
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*/
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int of_attach_node(struct device_node *np)
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{
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unsigned long flags;
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int rc;
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rc = of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
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if (rc)
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return rc;
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raw_spin_lock_irqsave(&devtree_lock, flags);
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np->sibling = np->parent->child;
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np->allnext = np->parent->allnext;
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np->parent->allnext = np;
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np->parent->child = np;
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of_node_clear_flag(np, OF_DETACHED);
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raw_spin_unlock_irqrestore(&devtree_lock, flags);
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of_node_add(np);
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return 0;
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}
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/**
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* of_detach_node() - "Unplug" a node from the device tree.
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*
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* The caller must hold a reference to the node. The memory associated with
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* the node is not freed until its refcount goes to zero.
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*/
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int of_detach_node(struct device_node *np)
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{
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struct device_node *parent;
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unsigned long flags;
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int rc = 0;
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rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
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if (rc)
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return rc;
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raw_spin_lock_irqsave(&devtree_lock, flags);
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if (of_node_check_flag(np, OF_DETACHED)) {
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/* someone already detached it */
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raw_spin_unlock_irqrestore(&devtree_lock, flags);
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return rc;
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}
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parent = np->parent;
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if (!parent) {
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raw_spin_unlock_irqrestore(&devtree_lock, flags);
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return rc;
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}
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if (of_allnodes == np)
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of_allnodes = np->allnext;
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else {
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struct device_node *prev;
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for (prev = of_allnodes;
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prev->allnext != np;
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prev = prev->allnext)
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;
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prev->allnext = np->allnext;
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}
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if (parent->child == np)
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parent->child = np->sibling;
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else {
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struct device_node *prevsib;
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for (prevsib = np->parent->child;
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prevsib->sibling != np;
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prevsib = prevsib->sibling)
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;
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prevsib->sibling = np->sibling;
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}
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of_node_set_flag(np, OF_DETACHED);
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raw_spin_unlock_irqrestore(&devtree_lock, flags);
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of_node_remove(np);
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return rc;
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}
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/**
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* of_node_release() - release a dynamically allocated node
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* @kref: kref element of the node to be released
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*
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* In of_node_put() this function is passed to kref_put() as the destructor.
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*/
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void of_node_release(struct kobject *kobj)
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{
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struct device_node *node = kobj_to_device_node(kobj);
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struct property *prop = node->properties;
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/* We should never be releasing nodes that haven't been detached. */
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if (!of_node_check_flag(node, OF_DETACHED)) {
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pr_err("ERROR: Bad of_node_put() on %s\n", node->full_name);
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dump_stack();
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return;
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}
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if (!of_node_check_flag(node, OF_DYNAMIC))
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return;
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while (prop) {
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struct property *next = prop->next;
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kfree(prop->name);
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kfree(prop->value);
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kfree(prop);
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prop = next;
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if (!prop) {
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prop = node->deadprops;
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node->deadprops = NULL;
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}
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}
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kfree(node->full_name);
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kfree(node->data);
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kfree(node);
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}
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