linux/drivers/of/resolver.c
Amitoj Kaur Chawla 82f68756e9 of: resolver: Add missing of_node_get and of_node_put
In __of_find_node_by_full_name, add an of_node_get when detecting the
desired element, to ensure that it ends up with a reference count that is
one greater than on entering the function.

Also in __of_find_node_by_full_name, add an of_node_put on breaking
out of the for_each_child_of_node loop, to ensure that the reference
count of the returned value is not double incremented. This change
was made using Coccinelle.

The semantic patch used for this is as follows:

// <smpl>
@@
expression e;
local idexpression n;
@@

 for_each_child_of_node(..., n) {
   ... when != of_node_put(n)
       when != e = n
(
   return n;
|
+  of_node_put(n);
?  return ...;
)
   ...
 }
// </smpl

Finally, add an of_node_put in for_each_child_of_node in the function
__of_adjust_phandle_ref after the value returned by
__of_find_node_by_full_name is no longer useful.

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
2016-02-13 13:35:32 -06:00

416 lines
10 KiB
C

/*
* Functions for dealing with DT resolution
*
* Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
* Copyright (C) 2012 Texas Instruments Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/slab.h>
/* illegal phandle value (set when unresolved) */
#define OF_PHANDLE_ILLEGAL 0xdeadbeef
/**
* Find a node with the give full name by recursively following any of
* the child node links.
*/
static struct device_node *__of_find_node_by_full_name(struct device_node *node,
const char *full_name)
{
struct device_node *child, *found;
if (node == NULL)
return NULL;
/* check */
if (of_node_cmp(node->full_name, full_name) == 0)
return of_node_get(node);
for_each_child_of_node(node, child) {
found = __of_find_node_by_full_name(child, full_name);
if (found != NULL) {
of_node_put(child);
return found;
}
}
return NULL;
}
/*
* Find live tree's maximum phandle value.
*/
static phandle of_get_tree_max_phandle(void)
{
struct device_node *node;
phandle phandle;
unsigned long flags;
/* now search recursively */
raw_spin_lock_irqsave(&devtree_lock, flags);
phandle = 0;
for_each_of_allnodes(node) {
if (node->phandle != OF_PHANDLE_ILLEGAL &&
node->phandle > phandle)
phandle = node->phandle;
}
raw_spin_unlock_irqrestore(&devtree_lock, flags);
return phandle;
}
/*
* Adjust a subtree's phandle values by a given delta.
* Makes sure not to just adjust the device node's phandle value,
* but modify the phandle properties values as well.
*/
static void __of_adjust_tree_phandles(struct device_node *node,
int phandle_delta)
{
struct device_node *child;
struct property *prop;
phandle phandle;
/* first adjust the node's phandle direct value */
if (node->phandle != 0 && node->phandle != OF_PHANDLE_ILLEGAL)
node->phandle += phandle_delta;
/* now adjust phandle & linux,phandle values */
for_each_property_of_node(node, prop) {
/* only look for these two */
if (of_prop_cmp(prop->name, "phandle") != 0 &&
of_prop_cmp(prop->name, "linux,phandle") != 0)
continue;
/* must be big enough */
if (prop->length < 4)
continue;
/* read phandle value */
phandle = be32_to_cpup(prop->value);
if (phandle == OF_PHANDLE_ILLEGAL) /* unresolved */
continue;
/* adjust */
*(uint32_t *)prop->value = cpu_to_be32(node->phandle);
}
/* now do the children recursively */
for_each_child_of_node(node, child)
__of_adjust_tree_phandles(child, phandle_delta);
}
static int __of_adjust_phandle_ref(struct device_node *node,
struct property *rprop, int value)
{
phandle phandle;
struct device_node *refnode;
struct property *sprop;
char *propval, *propcur, *propend, *nodestr, *propstr, *s;
int offset, propcurlen;
int err = 0;
/* make a copy */
propval = kmalloc(rprop->length, GFP_KERNEL);
if (!propval) {
pr_err("%s: Could not copy value of '%s'\n",
__func__, rprop->name);
return -ENOMEM;
}
memcpy(propval, rprop->value, rprop->length);
propend = propval + rprop->length;
for (propcur = propval; propcur < propend; propcur += propcurlen + 1) {
propcurlen = strlen(propcur);
nodestr = propcur;
s = strchr(propcur, ':');
if (!s) {
pr_err("%s: Illegal symbol entry '%s' (1)\n",
__func__, propcur);
err = -EINVAL;
goto err_fail;
}
*s++ = '\0';
propstr = s;
s = strchr(s, ':');
if (!s) {
pr_err("%s: Illegal symbol entry '%s' (2)\n",
__func__, (char *)rprop->value);
err = -EINVAL;
goto err_fail;
}
*s++ = '\0';
err = kstrtoint(s, 10, &offset);
if (err != 0) {
pr_err("%s: Could get offset '%s'\n",
__func__, (char *)rprop->value);
goto err_fail;
}
/* look into the resolve node for the full path */
refnode = __of_find_node_by_full_name(node, nodestr);
if (!refnode) {
pr_warn("%s: Could not find refnode '%s'\n",
__func__, (char *)rprop->value);
continue;
}
/* now find the property */
for_each_property_of_node(refnode, sprop) {
if (of_prop_cmp(sprop->name, propstr) == 0)
break;
}
of_node_put(refnode);
if (!sprop) {
pr_err("%s: Could not find property '%s'\n",
__func__, (char *)rprop->value);
err = -ENOENT;
goto err_fail;
}
phandle = value;
*(__be32 *)(sprop->value + offset) = cpu_to_be32(phandle);
}
err_fail:
kfree(propval);
return err;
}
/* compare nodes taking into account that 'name' strips out the @ part */
static int __of_node_name_cmp(const struct device_node *dn1,
const struct device_node *dn2)
{
const char *n1 = strrchr(dn1->full_name, '/') ? : "/";
const char *n2 = strrchr(dn2->full_name, '/') ? : "/";
return of_node_cmp(n1, n2);
}
/*
* Adjust the local phandle references by the given phandle delta.
* Assumes the existances of a __local_fixups__ node at the root.
* Assumes that __of_verify_tree_phandle_references has been called.
* Does not take any devtree locks so make sure you call this on a tree
* which is at the detached state.
*/
static int __of_adjust_tree_phandle_references(struct device_node *node,
struct device_node *target, int phandle_delta)
{
struct device_node *child, *childtarget;
struct property *rprop, *sprop;
int err, i, count;
unsigned int off;
phandle phandle;
if (node == NULL)
return 0;
for_each_property_of_node(node, rprop) {
/* skip properties added automatically */
if (of_prop_cmp(rprop->name, "name") == 0 ||
of_prop_cmp(rprop->name, "phandle") == 0 ||
of_prop_cmp(rprop->name, "linux,phandle") == 0)
continue;
if ((rprop->length % 4) != 0 || rprop->length == 0) {
pr_err("%s: Illegal property (size) '%s' @%s\n",
__func__, rprop->name, node->full_name);
return -EINVAL;
}
count = rprop->length / sizeof(__be32);
/* now find the target property */
for_each_property_of_node(target, sprop) {
if (of_prop_cmp(sprop->name, rprop->name) == 0)
break;
}
if (sprop == NULL) {
pr_err("%s: Could not find target property '%s' @%s\n",
__func__, rprop->name, node->full_name);
return -EINVAL;
}
for (i = 0; i < count; i++) {
off = be32_to_cpu(((__be32 *)rprop->value)[i]);
/* make sure the offset doesn't overstep (even wrap) */
if (off >= sprop->length ||
(off + 4) > sprop->length) {
pr_err("%s: Illegal property '%s' @%s\n",
__func__, rprop->name,
node->full_name);
return -EINVAL;
}
if (phandle_delta) {
/* adjust */
phandle = be32_to_cpu(*(__be32 *)(sprop->value + off));
phandle += phandle_delta;
*(__be32 *)(sprop->value + off) = cpu_to_be32(phandle);
}
}
}
for_each_child_of_node(node, child) {
for_each_child_of_node(target, childtarget)
if (__of_node_name_cmp(child, childtarget) == 0)
break;
if (!childtarget) {
pr_err("%s: Could not find target child '%s' @%s\n",
__func__, child->name, node->full_name);
return -EINVAL;
}
err = __of_adjust_tree_phandle_references(child, childtarget,
phandle_delta);
if (err != 0)
return err;
}
return 0;
}
/**
* of_resolve - Resolve the given node against the live tree.
*
* @resolve: Node to resolve
*
* Perform dynamic Device Tree resolution against the live tree
* to the given node to resolve. This depends on the live tree
* having a __symbols__ node, and the resolve node the __fixups__ &
* __local_fixups__ nodes (if needed).
* The result of the operation is a resolve node that it's contents
* are fit to be inserted or operate upon the live tree.
* Returns 0 on success or a negative error value on error.
*/
int of_resolve_phandles(struct device_node *resolve)
{
struct device_node *child, *childroot, *refnode;
struct device_node *root_sym, *resolve_sym, *resolve_fix;
struct property *rprop;
const char *refpath;
phandle phandle, phandle_delta;
int err;
/* the resolve node must exist, and be detached */
if (!resolve || !of_node_check_flag(resolve, OF_DETACHED))
return -EINVAL;
/* first we need to adjust the phandles */
phandle_delta = of_get_tree_max_phandle() + 1;
__of_adjust_tree_phandles(resolve, phandle_delta);
/* locate the local fixups */
childroot = NULL;
for_each_child_of_node(resolve, childroot)
if (of_node_cmp(childroot->name, "__local_fixups__") == 0)
break;
if (childroot != NULL) {
/* resolve root is guaranteed to be the '/' */
err = __of_adjust_tree_phandle_references(childroot,
resolve, 0);
if (err != 0)
return err;
BUG_ON(__of_adjust_tree_phandle_references(childroot,
resolve, phandle_delta));
}
root_sym = NULL;
resolve_sym = NULL;
resolve_fix = NULL;
/* this may fail (if no fixups are required) */
root_sym = of_find_node_by_path("/__symbols__");
/* locate the symbols & fixups nodes on resolve */
for_each_child_of_node(resolve, child) {
if (!resolve_sym &&
of_node_cmp(child->name, "__symbols__") == 0)
resolve_sym = child;
if (!resolve_fix &&
of_node_cmp(child->name, "__fixups__") == 0)
resolve_fix = child;
/* both found, don't bother anymore */
if (resolve_sym && resolve_fix)
break;
}
/* we do allow for the case where no fixups are needed */
if (!resolve_fix) {
err = 0; /* no error */
goto out;
}
/* we need to fixup, but no root symbols... */
if (!root_sym) {
err = -EINVAL;
goto out;
}
for_each_property_of_node(resolve_fix, rprop) {
/* skip properties added automatically */
if (of_prop_cmp(rprop->name, "name") == 0)
continue;
err = of_property_read_string(root_sym,
rprop->name, &refpath);
if (err != 0) {
pr_err("%s: Could not find symbol '%s'\n",
__func__, rprop->name);
goto out;
}
refnode = of_find_node_by_path(refpath);
if (!refnode) {
pr_err("%s: Could not find node by path '%s'\n",
__func__, refpath);
err = -ENOENT;
goto out;
}
phandle = refnode->phandle;
of_node_put(refnode);
pr_debug("%s: %s phandle is 0x%08x\n",
__func__, rprop->name, phandle);
err = __of_adjust_phandle_ref(resolve, rprop, phandle);
if (err)
break;
}
out:
/* NULL is handled by of_node_put as NOP */
of_node_put(root_sym);
return err;
}
EXPORT_SYMBOL_GPL(of_resolve_phandles);