/*
* Procedures for creating, accessing and interpreting the device tree.
*
* Paul Mackerras August 1996.
* Copyright (C) 1996-2005 Paul Mackerras.
*
* Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
* {engebret|bergner}@us.ibm.com
*
* Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
*
* Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
* Grant Likely.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/of.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
struct device_node *allnodes;
struct device_node *of_chosen;
/* use when traversing tree through the allnext, child, sibling,
* or parent members of struct device_node.
*/
DEFINE_RWLOCK(devtree_lock);
int of_n_addr_cells(struct device_node *np)
{
const int *ip;
do {
if (np->parent)
np = np->parent;
ip = of_get_property(np, "#address-cells", NULL);
if (ip)
return be32_to_cpup(ip);
} while (np->parent);
/* No #address-cells property for the root node */
return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
}
EXPORT_SYMBOL(of_n_addr_cells);
int of_n_size_cells(struct device_node *np)
{
const int *ip;
do {
if (np->parent)
np = np->parent;
ip = of_get_property(np, "#size-cells", NULL);
if (ip)
return be32_to_cpup(ip);
} while (np->parent);
/* No #size-cells property for the root node */
return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
}
EXPORT_SYMBOL(of_n_size_cells);
#if !defined(CONFIG_SPARC) /* SPARC doesn't do ref counting (yet) */
/**
* 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)
kref_get(&node->kref);
return node;
}
EXPORT_SYMBOL(of_node_get);
static inline struct device_node *kref_to_device_node(struct kref *kref)
{
return container_of(kref, struct device_node, kref);
}
/**
* 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.
*/
static void of_node_release(struct kref *kref)
{
struct device_node *node = kref_to_device_node(kref);
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();
kref_init(&node->kref);
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);
}
/**
* 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)
kref_put(&node->kref, of_node_release);
}
EXPORT_SYMBOL(of_node_put);
#endif /* !CONFIG_SPARC */
struct property *of_find_property(const struct device_node *np,
const char *name,
int *lenp)
{
struct property *pp;
if (!np)
return NULL;
read_lock(&devtree_lock);
for (pp = np->properties; pp != 0; pp = pp->next) {
if (of_prop_cmp(pp->name, name) == 0) {
if (lenp != 0)
*lenp = pp->length;
break;
}
}
read_unlock(&devtree_lock);
return pp;
}
EXPORT_SYMBOL(of_find_property);
/**
* of_find_all_nodes - Get next node in global list
* @prev: Previous node or NULL to start iteration
* of_node_put() will be called on it
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_all_nodes(struct device_node *prev)
{
struct device_node *np;
read_lock(&devtree_lock);
np = prev ? prev->allnext : allnodes;
for (; np != NULL; np = np->allnext)
if (of_node_get(np))
break;
of_node_put(prev);
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_find_all_nodes);
/*
* Find a property with a given name for a given node
* and return the value.
*/
const void *of_get_property(const struct device_node *np, const char *name,
int *lenp)
{
struct property *pp = of_find_property(np, name, lenp);
return pp ? pp->value : NULL;
}
EXPORT_SYMBOL(of_get_property);
/** Checks if the given "compat" string matches one of the strings in
* the device's "compatible" property
*/
int of_device_is_compatible(const struct device_node *device,
const char *compat)
{
const char* cp;
int cplen, l;
cp = of_get_property(device, "compatible", &cplen);
if (cp == NULL)
return 0;
while (cplen > 0) {
if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
return 1;
l = strlen(cp) + 1;
cp += l;
cplen -= l;
}
return 0;
}
EXPORT_SYMBOL(of_device_is_compatible);
/**
* of_machine_is_compatible - Test root of device tree for a given compatible value
* @compat: compatible string to look for in root node's compatible property.
*
* Returns true if the root node has the given value in its
* compatible property.
*/
int of_machine_is_compatible(const char *compat)
{
struct device_node *root;
int rc = 0;
root = of_find_node_by_path("/");
if (root) {
rc = of_device_is_compatible(root, compat);
of_node_put(root);
}
return rc;
}
EXPORT_SYMBOL(of_machine_is_compatible);
/**
* of_device_is_available - check if a device is available for use
*
* @device: Node to check for availability
*
* Returns 1 if the status property is absent or set to "okay" or "ok",
* 0 otherwise
*/
int of_device_is_available(const struct device_node *device)
{
const char *status;
int statlen;
status = of_get_property(device, "status", &statlen);
if (status == NULL)
return 1;
if (statlen > 0) {
if (!strcmp(status, "okay") || !strcmp(status, "ok"))
return 1;
}
return 0;
}
EXPORT_SYMBOL(of_device_is_available);
/**
* of_get_parent - Get a node's parent if any
* @node: Node to get parent
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_get_parent(const struct device_node *node)
{
struct device_node *np;
if (!node)
return NULL;
read_lock(&devtree_lock);
np = of_node_get(node->parent);
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_get_parent);
/**
* of_get_next_parent - Iterate to a node's parent
* @node: Node to get parent of
*
* This is like of_get_parent() except that it drops the
* refcount on the passed node, making it suitable for iterating
* through a node's parents.
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_get_next_parent(struct device_node *node)
{
struct device_node *parent;
if (!node)
return NULL;
read_lock(&devtree_lock);
parent = of_node_get(node->parent);
of_node_put(node);
read_unlock(&devtree_lock);
return parent;
}
/**
* of_get_next_child - Iterate a node childs
* @node: parent node
* @prev: previous child of the parent node, or NULL to get first
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_get_next_child(const struct device_node *node,
struct device_node *prev)
{
struct device_node *next;
read_lock(&devtree_lock);
next = prev ? prev->sibling : node->child;
for (; next; next = next->sibling)
if (of_node_get(next))
break;
of_node_put(prev);
read_unlock(&devtree_lock);
return next;
}
EXPORT_SYMBOL(of_get_next_child);
/**
* of_find_node_by_path - Find a node matching a full OF path
* @path: The full path to match
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_node_by_path(const char *path)
{
struct device_node *np = allnodes;
read_lock(&devtree_lock);
for (; np; np = np->allnext) {
if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
&& of_node_get(np))
break;
}
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_find_node_by_path);
/**
* of_find_node_by_name - Find a node by its "name" property
* @from: The node to start searching from or NULL, the node
* you pass will not be searched, only the next one
* will; typically, you pass what the previous call
* returned. of_node_put() will be called on it
* @name: The name string to match against
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_node_by_name(struct device_node *from,
const char *name)
{
struct device_node *np;
read_lock(&devtree_lock);
np = from ? from->allnext : allnodes;
for (; np; np = np->allnext)
if (np->name && (of_node_cmp(np->name, name) == 0)
&& of_node_get(np))
break;
of_node_put(from);
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_find_node_by_name);
/**
* of_find_node_by_type - Find a node by its "device_type" property
* @from: The node to start searching from, or NULL to start searching
* the entire device tree. The node you pass will not be
* searched, only the next one will; typically, you pass
* what the previous call returned. of_node_put() will be
* called on from for you.
* @type: The type string to match against
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_node_by_type(struct device_node *from,
const char *type)
{
struct device_node *np;
read_lock(&devtree_lock);
np = from ? from->allnext : allnodes;
for (; np; np = np->allnext)
if (np->type && (of_node_cmp(np->type, type) == 0)
&& of_node_get(np))
break;
of_node_put(from);
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_find_node_by_type);
/**
* of_find_compatible_node - Find a node based on type and one of the
* tokens in its "compatible" property
* @from: The node to start searching from or NULL, the node
* you pass will not be searched, only the next one
* will; typically, you pass what the previous call
* returned. of_node_put() will be called on it
* @type: The type string to match "device_type" or NULL to ignore
* @compatible: The string to match to one of the tokens in the device
* "compatible" list.
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_compatible_node(struct device_node *from,
const char *type, const char *compatible)
{
struct device_node *np;
read_lock(&devtree_lock);
np = from ? from->allnext : allnodes;
for (; np; np = np->allnext) {
if (type
&& !(np->type && (of_node_cmp(np->type, type) == 0)))
continue;
if (of_device_is_compatible(np, compatible) && of_node_get(np))
break;
}
of_node_put(from);
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_find_compatible_node);
/**
* of_find_node_with_property - Find a node which has a property with
* the given name.
* @from: The node to start searching from or NULL, the node
* you pass will not be searched, only the next one
* will; typically, you pass what the previous call
* returned. of_node_put() will be called on it
* @prop_name: The name of the property to look for.
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_node_with_property(struct device_node *from,
const char *prop_name)
{
struct device_node *np;
struct property *pp;
read_lock(&devtree_lock);
np = from ? from->allnext : allnodes;
for (; np; np = np->allnext) {
for (pp = np->properties; pp != 0; pp = pp->next) {
if (of_prop_cmp(pp->name, prop_name) == 0) {
of_node_get(np);
goto out;
}
}
}
out:
of_node_put(from);
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_find_node_with_property);
/**
* of_match_node - Tell if an device_node has a matching of_match structure
* @matches: array of of device match structures to search in
* @node: the of device structure to match against
*
* Low level utility function used by device matching.
*/
const struct of_device_id *of_match_node(const struct of_device_id *matches,
const struct device_node *node)
{
while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
int match = 1;
if (matches->name[0])
match &= node->name
&& !strcmp(matches->name, node->name);
if (matches->type[0])
match &= node->type
&& !strcmp(matches->type, node->type);
if (matches->compatible[0])
match &= of_device_is_compatible(node,
matches->compatible);
if (match)
return matches;
matches++;
}
return NULL;
}
EXPORT_SYMBOL(of_match_node);
/**
* of_find_matching_node - Find a node based on an of_device_id match
* table.
* @from: The node to start searching from or NULL, the node
* you pass will not be searched, only the next one
* will; typically, you pass what the previous call
* returned. of_node_put() will be called on it
* @matches: array of of device match structures to search in
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_matching_node(struct device_node *from,
const struct of_device_id *matches)
{
struct device_node *np;
read_lock(&devtree_lock);
np = from ? from->allnext : allnodes;
for (; np; np = np->allnext) {
if (of_match_node(matches, np) && of_node_get(np))
break;
}
of_node_put(from);
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_find_matching_node);
/**
* of_modalias_node - Lookup appropriate modalias for a device node
* @node: pointer to a device tree node
* @modalias: Pointer to buffer that modalias value will be copied into
* @len: Length of modalias value
*
* Based on the value of the compatible property, this routine will attempt
* to choose an appropriate modalias value for a particular device tree node.
* It does this by stripping the manufacturer prefix (as delimited by a ',')
* from the first entry in the compatible list property.
*
* This routine returns 0 on success, <0 on failure.
*/
int of_modalias_node(struct device_node *node, char *modalias, int len)
{
const char *compatible, *p;
int cplen;
compatible = of_get_property(node, "compatible", &cplen);
if (!compatible || strlen(compatible) > cplen)
return -ENODEV;
p = strchr(compatible, ',');
strlcpy(modalias, p ? p + 1 : compatible, len);
return 0;
}
EXPORT_SYMBOL_GPL(of_modalias_node);
/**
* of_find_node_by_phandle - Find a node given a phandle
* @handle: phandle of the node to find
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_node_by_phandle(phandle handle)
{
struct device_node *np;
read_lock(&devtree_lock);
for (np = allnodes; np; np = np->allnext)
if (np->phandle == handle)
break;
of_node_get(np);
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_find_node_by_phandle);
/**
* of_parse_phandle - Resolve a phandle property to a device_node pointer
* @np: Pointer to device node holding phandle property
* @phandle_name: Name of property holding a phandle value
* @index: For properties holding a table of phandles, this is the index into
* the table
*
* Returns the device_node pointer with refcount incremented. Use
* of_node_put() on it when done.
*/
struct device_node *
of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
{
const __be32 *phandle;
int size;
phandle = of_get_property(np, phandle_name, &size);
if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
return NULL;
return of_find_node_by_phandle(be32_to_cpup(phandle + index));
}
EXPORT_SYMBOL(of_parse_phandle);
/**
* of_parse_phandles_with_args - Find a node pointed by phandle in a list
* @np: pointer to a device tree node containing a list
* @list_name: property name that contains a list
* @cells_name: property name that specifies phandles' arguments count
* @index: index of a phandle to parse out
* @out_node: optional pointer to device_node struct pointer (will be filled)
* @out_args: optional pointer to arguments pointer (will be filled)
*
* This function is useful to parse lists of phandles and their arguments.
* Returns 0 on success and fills out_node and out_args, on error returns
* appropriate errno value.
*
* Example:
*
* phandle1: node1 {
* #list-cells = <2>;
* }
*
* phandle2: node2 {
* #list-cells = <1>;
* }
*
* node3 {
* list = <&phandle1 1 2 &phandle2 3>;
* }
*
* To get a device_node of the `node2' node you may call this:
* of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
*/
int of_parse_phandles_with_args(struct device_node *np, const char *list_name,
const char *cells_name, int index,
struct device_node **out_node,
const void **out_args)
{
int ret = -EINVAL;
const __be32 *list;
const __be32 *list_end;
int size;
int cur_index = 0;
struct device_node *node = NULL;
const void *args = NULL;
list = of_get_property(np, list_name, &size);
if (!list) {
ret = -ENOENT;
goto err0;
}
list_end = list + size / sizeof(*list);
while (list < list_end) {
const __be32 *cells;
phandle phandle;
phandle = be32_to_cpup(list++);
args = list;
/* one cell hole in the list = <>; */
if (!phandle)
goto next;
node = of_find_node_by_phandle(phandle);
if (!node) {
pr_debug("%s: could not find phandle\n",
np->full_name);
goto err0;
}
cells = of_get_property(node, cells_name, &size);
if (!cells || size != sizeof(*cells)) {
pr_debug("%s: could not get %s for %s\n",
np->full_name, cells_name, node->full_name);
goto err1;
}
list += be32_to_cpup(cells);
if (list > list_end) {
pr_debug("%s: insufficient arguments length\n",
np->full_name);
goto err1;
}
next:
if (cur_index == index)
break;
of_node_put(node);
node = NULL;
args = NULL;
cur_index++;
}
if (!node) {
/*
* args w/o node indicates that the loop above has stopped at
* the 'hole' cell. Report this differently.
*/
if (args)
ret = -EEXIST;
else
ret = -ENOENT;
goto err0;
}
if (out_node)
*out_node = node;
if (out_args)
*out_args = args;
return 0;
err1:
of_node_put(node);
err0:
pr_debug("%s failed with status %d\n", __func__, ret);
return ret;
}
EXPORT_SYMBOL(of_parse_phandles_with_args);
/**
* prom_add_property - Add a property to a node
*/
int prom_add_property(struct device_node *np, struct property *prop)
{
struct property **next;
unsigned long flags;
prop->next = NULL;
write_lock_irqsave(&devtree_lock, flags);
next = &np->properties;
while (*next) {
if (strcmp(prop->name, (*next)->name) == 0) {
/* duplicate ! don't insert it */
write_unlock_irqrestore(&devtree_lock, flags);
return -1;
}
next = &(*next)->next;
}
*next = prop;
write_unlock_irqrestore(&devtree_lock, flags);
#ifdef CONFIG_PROC_DEVICETREE
/* try to add to proc as well if it was initialized */
if (np->pde)
proc_device_tree_add_prop(np->pde, prop);
#endif /* CONFIG_PROC_DEVICETREE */
return 0;
}
/**
* prom_remove_property - Remove a property from a node.
*
* Note that we don't actually remove it, since we have given out
* who-knows-how-many pointers to the data using get-property.
* Instead we just move the property to the "dead properties"
* list, so it won't be found any more.
*/
int prom_remove_property(struct device_node *np, struct property *prop)
{
struct property **next;
unsigned long flags;
int found = 0;
write_lock_irqsave(&devtree_lock, flags);
next = &np->properties;
while (*next) {
if (*next == prop) {
/* found the node */
*next = prop->next;
prop->next = np->deadprops;
np->deadprops = prop;
found = 1;
break;
}
next = &(*next)->next;
}
write_unlock_irqrestore(&devtree_lock, flags);
if (!found)
return -ENODEV;
#ifdef CONFIG_PROC_DEVICETREE
/* try to remove the proc node as well */
if (np->pde)
proc_device_tree_remove_prop(np->pde, prop);
#endif /* CONFIG_PROC_DEVICETREE */
return 0;
}
/*
* prom_update_property - Update a property in a node.
*
* Note that we don't actually remove it, since we have given out
* who-knows-how-many pointers to the data using get-property.
* Instead we just move the property to the "dead properties" list,
* and add the new property to the property list
*/
int prom_update_property(struct device_node *np,
struct property *newprop,
struct property *oldprop)
{
struct property **next;
unsigned long flags;
int found = 0;
write_lock_irqsave(&devtree_lock, flags);
next = &np->properties;
while (*next) {
if (*next == oldprop) {
/* found the node */
newprop->next = oldprop->next;
*next = newprop;
oldprop->next = np->deadprops;
np->deadprops = oldprop;
found = 1;
break;
}
next = &(*next)->next;
}
write_unlock_irqrestore(&devtree_lock, flags);
if (!found)
return -ENODEV;
#ifdef CONFIG_PROC_DEVICETREE
/* try to add to proc as well if it was initialized */
if (np->pde)
proc_device_tree_update_prop(np->pde, newprop, oldprop);
#endif /* CONFIG_PROC_DEVICETREE */
return 0;
}
#if defined(CONFIG_OF_DYNAMIC)
/*
* 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.
*/
/**
* of_attach_node - Plug a device node into the tree and global list.
*/
void of_attach_node(struct device_node *np)
{
unsigned long flags;
write_lock_irqsave(&devtree_lock, flags);
np->sibling = np->parent->child;
np->allnext = allnodes;
np->parent->child = np;
allnodes = np;
write_unlock_irqrestore(&devtree_lock, flags);
}
/**
* 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.
*/
void of_detach_node(struct device_node *np)
{
struct device_node *parent;
unsigned long flags;
write_lock_irqsave(&devtree_lock, flags);
parent = np->parent;
if (!parent)
goto out_unlock;
if (allnodes == np)
allnodes = np->allnext;
else {
struct device_node *prev;
for (prev = 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);
out_unlock:
write_unlock_irqrestore(&devtree_lock, flags);
}
#endif /* defined(CONFIG_OF_DYNAMIC) */
