linux/drivers/of/dynamic.c
Saravana Kannan 7b337cb3eb driver core: Add fwnode link support
Add support for creating supplier-consumer links between fwnodes.  It is
intended for internal use the driver core and generic firmware support
code (eg. Device Tree, ACPI), so it is simple by design and the API
provided is limited.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-9-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09 19:10:21 +01:00

930 lines
23 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* 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.
*/
#define pr_fmt(fmt) "OF: " fmt
#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"
static struct device_node *kobj_to_device_node(struct kobject *kobj)
{
return container_of(kobj, struct device_node, kobj);
}
/**
* 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 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);
#ifdef DEBUG
const char *action_names[] = {
[OF_RECONFIG_ATTACH_NODE] = "ATTACH_NODE",
[OF_RECONFIG_DETACH_NODE] = "DETACH_NODE",
[OF_RECONFIG_ADD_PROPERTY] = "ADD_PROPERTY",
[OF_RECONFIG_REMOVE_PROPERTY] = "REMOVE_PROPERTY",
[OF_RECONFIG_UPDATE_PROPERTY] = "UPDATE_PROPERTY",
};
#endif
int of_reconfig_notify(unsigned long action, struct of_reconfig_data *p)
{
int rc;
#ifdef DEBUG
struct of_reconfig_data *pr = p;
switch (action) {
case OF_RECONFIG_ATTACH_NODE:
case OF_RECONFIG_DETACH_NODE:
pr_debug("notify %-15s %pOF\n", action_names[action],
pr->dn);
break;
case OF_RECONFIG_ADD_PROPERTY:
case OF_RECONFIG_REMOVE_PROPERTY:
case OF_RECONFIG_UPDATE_PROPERTY:
pr_debug("notify %-15s %pOF:%s\n", action_names[action],
pr->dn, pr->prop->name);
break;
}
#endif
rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
return notifier_to_errno(rc);
}
/*
* of_reconfig_get_state_change() - Returns new state of device
* @action - action of the of notifier
* @arg - argument of the of notifier
*
* Returns the new state of a device based on the notifier used.
* Returns 0 on device going from enabled to disabled, 1 on device
* going from disabled to enabled and -1 on no change.
*/
int of_reconfig_get_state_change(unsigned long action, struct of_reconfig_data *pr)
{
struct property *prop, *old_prop = NULL;
int is_status, status_state, old_status_state, prev_state, new_state;
/* figure out if a device should be created or destroyed */
switch (action) {
case OF_RECONFIG_ATTACH_NODE:
case OF_RECONFIG_DETACH_NODE:
prop = of_find_property(pr->dn, "status", NULL);
break;
case OF_RECONFIG_ADD_PROPERTY:
case OF_RECONFIG_REMOVE_PROPERTY:
prop = pr->prop;
break;
case OF_RECONFIG_UPDATE_PROPERTY:
prop = pr->prop;
old_prop = pr->old_prop;
break;
default:
return OF_RECONFIG_NO_CHANGE;
}
is_status = 0;
status_state = -1;
old_status_state = -1;
prev_state = -1;
new_state = -1;
if (prop && !strcmp(prop->name, "status")) {
is_status = 1;
status_state = !strcmp(prop->value, "okay") ||
!strcmp(prop->value, "ok");
if (old_prop)
old_status_state = !strcmp(old_prop->value, "okay") ||
!strcmp(old_prop->value, "ok");
}
switch (action) {
case OF_RECONFIG_ATTACH_NODE:
prev_state = 0;
/* -1 & 0 status either missing or okay */
new_state = status_state != 0;
break;
case OF_RECONFIG_DETACH_NODE:
/* -1 & 0 status either missing or okay */
prev_state = status_state != 0;
new_state = 0;
break;
case OF_RECONFIG_ADD_PROPERTY:
if (is_status) {
/* no status property -> enabled (legacy) */
prev_state = 1;
new_state = status_state;
}
break;
case OF_RECONFIG_REMOVE_PROPERTY:
if (is_status) {
prev_state = status_state;
/* no status property -> enabled (legacy) */
new_state = 1;
}
break;
case OF_RECONFIG_UPDATE_PROPERTY:
if (is_status) {
prev_state = old_status_state != 0;
new_state = status_state != 0;
}
break;
}
if (prev_state == new_state)
return OF_RECONFIG_NO_CHANGE;
return new_state ? OF_RECONFIG_CHANGE_ADD : OF_RECONFIG_CHANGE_REMOVE;
}
EXPORT_SYMBOL_GPL(of_reconfig_get_state_change);
int of_property_notify(int action, struct device_node *np,
struct property *prop, struct property *oldprop)
{
struct of_reconfig_data pr;
/* only call notifiers if the node is attached */
if (!of_node_is_attached(np))
return 0;
pr.dn = np;
pr.prop = prop;
pr.old_prop = oldprop;
return of_reconfig_notify(action, &pr);
}
static void __of_attach_node(struct device_node *np)
{
const __be32 *phandle;
int sz;
if (!of_node_check_flag(np, OF_OVERLAY)) {
np->name = __of_get_property(np, "name", NULL);
if (!np->name)
np->name = "<NULL>";
phandle = __of_get_property(np, "phandle", &sz);
if (!phandle)
phandle = __of_get_property(np, "linux,phandle", &sz);
if (IS_ENABLED(CONFIG_PPC_PSERIES) && !phandle)
phandle = __of_get_property(np, "ibm,phandle", &sz);
if (phandle && (sz >= 4))
np->phandle = be32_to_cpup(phandle);
else
np->phandle = 0;
}
np->child = NULL;
np->sibling = np->parent->child;
np->parent->child = np;
of_node_clear_flag(np, OF_DETACHED);
}
/**
* of_attach_node() - Plug a device node into the tree and global list.
*/
int of_attach_node(struct device_node *np)
{
struct of_reconfig_data rd;
unsigned long flags;
memset(&rd, 0, sizeof(rd));
rd.dn = np;
mutex_lock(&of_mutex);
raw_spin_lock_irqsave(&devtree_lock, flags);
__of_attach_node(np);
raw_spin_unlock_irqrestore(&devtree_lock, flags);
__of_attach_node_sysfs(np);
mutex_unlock(&of_mutex);
of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, &rd);
return 0;
}
void __of_detach_node(struct device_node *np)
{
struct device_node *parent;
if (WARN_ON(of_node_check_flag(np, OF_DETACHED)))
return;
parent = np->parent;
if (WARN_ON(!parent))
return;
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);
/* race with of_find_node_by_phandle() prevented by devtree_lock */
__of_phandle_cache_inv_entry(np->phandle);
}
/**
* of_detach_node() - "Unplug" a node from the device tree.
*/
int of_detach_node(struct device_node *np)
{
struct of_reconfig_data rd;
unsigned long flags;
memset(&rd, 0, sizeof(rd));
rd.dn = np;
mutex_lock(&of_mutex);
raw_spin_lock_irqsave(&devtree_lock, flags);
__of_detach_node(np);
raw_spin_unlock_irqrestore(&devtree_lock, flags);
__of_detach_node_sysfs(np);
mutex_unlock(&of_mutex);
of_reconfig_notify(OF_RECONFIG_DETACH_NODE, &rd);
return 0;
}
EXPORT_SYMBOL_GPL(of_detach_node);
static void property_list_free(struct property *prop_list)
{
struct property *prop, *next;
for (prop = prop_list; prop != NULL; prop = next) {
next = prop->next;
kfree(prop->name);
kfree(prop->value);
kfree(prop);
}
}
/**
* 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);
/* 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 %pOF\n", node);
dump_stack();
return;
}
if (!of_node_check_flag(node, OF_DYNAMIC))
return;
if (of_node_check_flag(node, OF_OVERLAY)) {
if (!of_node_check_flag(node, OF_OVERLAY_FREE_CSET)) {
/* premature refcount of zero, do not free memory */
pr_err("ERROR: memory leak before free overlay changeset, %pOF\n",
node);
return;
}
/*
* If node->properties non-empty then properties were added
* to this node either by different overlay that has not
* yet been removed, or by a non-overlay mechanism.
*/
if (node->properties)
pr_err("ERROR: %s(), unexpected properties in %pOF\n",
__func__, node);
}
property_list_free(node->properties);
property_list_free(node->deadprops);
fwnode_links_purge(of_fwnode_handle(node));
kfree(node->full_name);
kfree(node->data);
kfree(node);
}
/**
* __of_prop_dup - Copy a property dynamically.
* @prop: Property to copy
* @allocflags: Allocation flags (typically pass GFP_KERNEL)
*
* Copy a property by dynamically allocating the memory of both the
* property structure and the property name & contents. The property's
* flags have the OF_DYNAMIC bit set so that we can differentiate between
* dynamically allocated properties and not.
* Returns the newly allocated property or NULL on out of memory error.
*/
struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
{
struct property *new;
new = kzalloc(sizeof(*new), allocflags);
if (!new)
return NULL;
/*
* NOTE: There is no check for zero length value.
* In case of a boolean property, this will allocate a value
* of zero bytes. We do this to work around the use
* of of_get_property() calls on boolean values.
*/
new->name = kstrdup(prop->name, allocflags);
new->value = kmemdup(prop->value, prop->length, allocflags);
new->length = prop->length;
if (!new->name || !new->value)
goto err_free;
/* mark the property as dynamic */
of_property_set_flag(new, OF_DYNAMIC);
return new;
err_free:
kfree(new->name);
kfree(new->value);
kfree(new);
return NULL;
}
/**
* __of_node_dup() - Duplicate or create an empty device node dynamically.
* @np: if not NULL, contains properties to be duplicated in new node
* @full_name: string value to be duplicated into new node's full_name field
*
* Create a device tree node, optionally duplicating the properties of
* another node. The node data are dynamically allocated and all the node
* flags have the OF_DYNAMIC & OF_DETACHED bits set.
*
* Returns the newly allocated node or NULL on out of memory error.
*/
struct device_node *__of_node_dup(const struct device_node *np,
const char *full_name)
{
struct device_node *node;
node = kzalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return NULL;
node->full_name = kstrdup(full_name, GFP_KERNEL);
if (!node->full_name) {
kfree(node);
return NULL;
}
of_node_set_flag(node, OF_DYNAMIC);
of_node_set_flag(node, OF_DETACHED);
of_node_init(node);
/* Iterate over and duplicate all properties */
if (np) {
struct property *pp, *new_pp;
for_each_property_of_node(np, pp) {
new_pp = __of_prop_dup(pp, GFP_KERNEL);
if (!new_pp)
goto err_prop;
if (__of_add_property(node, new_pp)) {
kfree(new_pp->name);
kfree(new_pp->value);
kfree(new_pp);
goto err_prop;
}
}
}
return node;
err_prop:
of_node_put(node); /* Frees the node and properties */
return NULL;
}
static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
{
if (ce->action == OF_RECONFIG_ATTACH_NODE &&
of_node_check_flag(ce->np, OF_OVERLAY)) {
if (kref_read(&ce->np->kobj.kref) > 1) {
pr_err("ERROR: memory leak, expected refcount 1 instead of %d, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node %pOF\n",
kref_read(&ce->np->kobj.kref), ce->np);
} else {
of_node_set_flag(ce->np, OF_OVERLAY_FREE_CSET);
}
}
of_node_put(ce->np);
list_del(&ce->node);
kfree(ce);
}
#ifdef DEBUG
static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
{
switch (ce->action) {
case OF_RECONFIG_ADD_PROPERTY:
case OF_RECONFIG_REMOVE_PROPERTY:
case OF_RECONFIG_UPDATE_PROPERTY:
pr_debug("cset<%p> %-15s %pOF/%s\n", ce, action_names[ce->action],
ce->np, ce->prop->name);
break;
case OF_RECONFIG_ATTACH_NODE:
case OF_RECONFIG_DETACH_NODE:
pr_debug("cset<%p> %-15s %pOF\n", ce, action_names[ce->action],
ce->np);
break;
}
}
#else
static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
{
/* empty */
}
#endif
static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
struct of_changeset_entry *rce)
{
memcpy(rce, ce, sizeof(*rce));
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
rce->action = OF_RECONFIG_DETACH_NODE;
break;
case OF_RECONFIG_DETACH_NODE:
rce->action = OF_RECONFIG_ATTACH_NODE;
break;
case OF_RECONFIG_ADD_PROPERTY:
rce->action = OF_RECONFIG_REMOVE_PROPERTY;
break;
case OF_RECONFIG_REMOVE_PROPERTY:
rce->action = OF_RECONFIG_ADD_PROPERTY;
break;
case OF_RECONFIG_UPDATE_PROPERTY:
rce->old_prop = ce->prop;
rce->prop = ce->old_prop;
/* update was used but original property did not exist */
if (!rce->prop) {
rce->action = OF_RECONFIG_REMOVE_PROPERTY;
rce->prop = ce->prop;
}
break;
}
}
static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
bool revert)
{
struct of_reconfig_data rd;
struct of_changeset_entry ce_inverted;
int ret = 0;
if (revert) {
__of_changeset_entry_invert(ce, &ce_inverted);
ce = &ce_inverted;
}
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
case OF_RECONFIG_DETACH_NODE:
memset(&rd, 0, sizeof(rd));
rd.dn = ce->np;
ret = of_reconfig_notify(ce->action, &rd);
break;
case OF_RECONFIG_ADD_PROPERTY:
case OF_RECONFIG_REMOVE_PROPERTY:
case OF_RECONFIG_UPDATE_PROPERTY:
ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
break;
default:
pr_err("invalid devicetree changeset action: %i\n",
(int)ce->action);
ret = -EINVAL;
}
if (ret)
pr_err("changeset notifier error @%pOF\n", ce->np);
return ret;
}
static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
{
struct property *old_prop, **propp;
unsigned long flags;
int ret = 0;
__of_changeset_entry_dump(ce);
raw_spin_lock_irqsave(&devtree_lock, flags);
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
__of_attach_node(ce->np);
break;
case OF_RECONFIG_DETACH_NODE:
__of_detach_node(ce->np);
break;
case OF_RECONFIG_ADD_PROPERTY:
/* If the property is in deadprops then it must be removed */
for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
if (*propp == ce->prop) {
*propp = ce->prop->next;
ce->prop->next = NULL;
break;
}
}
ret = __of_add_property(ce->np, ce->prop);
if (ret) {
pr_err("changeset: add_property failed @%pOF/%s\n",
ce->np,
ce->prop->name);
break;
}
break;
case OF_RECONFIG_REMOVE_PROPERTY:
ret = __of_remove_property(ce->np, ce->prop);
if (ret) {
pr_err("changeset: remove_property failed @%pOF/%s\n",
ce->np,
ce->prop->name);
break;
}
break;
case OF_RECONFIG_UPDATE_PROPERTY:
/* If the property is in deadprops then it must be removed */
for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
if (*propp == ce->prop) {
*propp = ce->prop->next;
ce->prop->next = NULL;
break;
}
}
ret = __of_update_property(ce->np, ce->prop, &old_prop);
if (ret) {
pr_err("changeset: update_property failed @%pOF/%s\n",
ce->np,
ce->prop->name);
break;
}
break;
default:
ret = -EINVAL;
}
raw_spin_unlock_irqrestore(&devtree_lock, flags);
if (ret)
return ret;
switch (ce->action) {
case OF_RECONFIG_ATTACH_NODE:
__of_attach_node_sysfs(ce->np);
break;
case OF_RECONFIG_DETACH_NODE:
__of_detach_node_sysfs(ce->np);
break;
case OF_RECONFIG_ADD_PROPERTY:
/* ignore duplicate names */
__of_add_property_sysfs(ce->np, ce->prop);
break;
case OF_RECONFIG_REMOVE_PROPERTY:
__of_remove_property_sysfs(ce->np, ce->prop);
break;
case OF_RECONFIG_UPDATE_PROPERTY:
__of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
break;
}
return 0;
}
static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
{
struct of_changeset_entry ce_inverted;
__of_changeset_entry_invert(ce, &ce_inverted);
return __of_changeset_entry_apply(&ce_inverted);
}
/**
* of_changeset_init - Initialize a changeset for use
*
* @ocs: changeset pointer
*
* Initialize a changeset structure
*/
void of_changeset_init(struct of_changeset *ocs)
{
memset(ocs, 0, sizeof(*ocs));
INIT_LIST_HEAD(&ocs->entries);
}
EXPORT_SYMBOL_GPL(of_changeset_init);
/**
* of_changeset_destroy - Destroy a changeset
*
* @ocs: changeset pointer
*
* Destroys a changeset. Note that if a changeset is applied,
* its changes to the tree cannot be reverted.
*/
void of_changeset_destroy(struct of_changeset *ocs)
{
struct of_changeset_entry *ce, *cen;
list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
__of_changeset_entry_destroy(ce);
}
EXPORT_SYMBOL_GPL(of_changeset_destroy);
/*
* Apply the changeset entries in @ocs.
* If apply fails, an attempt is made to revert the entries that were
* successfully applied.
*
* If multiple revert errors occur then only the final revert error is reported.
*
* Returns 0 on success, a negative error value in case of an error.
* If a revert error occurs, it is returned in *ret_revert.
*/
int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
{
struct of_changeset_entry *ce;
int ret, ret_tmp;
pr_debug("changeset: applying...\n");
list_for_each_entry(ce, &ocs->entries, node) {
ret = __of_changeset_entry_apply(ce);
if (ret) {
pr_err("Error applying changeset (%d)\n", ret);
list_for_each_entry_continue_reverse(ce, &ocs->entries,
node) {
ret_tmp = __of_changeset_entry_revert(ce);
if (ret_tmp)
*ret_revert = ret_tmp;
}
return ret;
}
}
return 0;
}
/*
* Returns 0 on success, a negative error value in case of an error.
*
* If multiple changeset entry notification errors occur then only the
* final notification error is reported.
*/
int __of_changeset_apply_notify(struct of_changeset *ocs)
{
struct of_changeset_entry *ce;
int ret = 0, ret_tmp;
pr_debug("changeset: emitting notifiers.\n");
/* drop the global lock while emitting notifiers */
mutex_unlock(&of_mutex);
list_for_each_entry(ce, &ocs->entries, node) {
ret_tmp = __of_changeset_entry_notify(ce, 0);
if (ret_tmp)
ret = ret_tmp;
}
mutex_lock(&of_mutex);
pr_debug("changeset: notifiers sent.\n");
return ret;
}
/*
* Returns 0 on success, a negative error value in case of an error.
*
* If a changeset entry apply fails, an attempt is made to revert any
* previous entries in the changeset. If any of the reverts fails,
* that failure is not reported. Thus the state of the device tree
* is unknown if an apply error occurs.
*/
static int __of_changeset_apply(struct of_changeset *ocs)
{
int ret, ret_revert = 0;
ret = __of_changeset_apply_entries(ocs, &ret_revert);
if (!ret)
ret = __of_changeset_apply_notify(ocs);
return ret;
}
/**
* of_changeset_apply - Applies a changeset
*
* @ocs: changeset pointer
*
* Applies a changeset to the live tree.
* Any side-effects of live tree state changes are applied here on
* success, like creation/destruction of devices and side-effects
* like creation of sysfs properties and directories.
* Returns 0 on success, a negative error value in case of an error.
* On error the partially applied effects are reverted.
*/
int of_changeset_apply(struct of_changeset *ocs)
{
int ret;
mutex_lock(&of_mutex);
ret = __of_changeset_apply(ocs);
mutex_unlock(&of_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(of_changeset_apply);
/*
* Revert the changeset entries in @ocs.
* If revert fails, an attempt is made to re-apply the entries that were
* successfully removed.
*
* If multiple re-apply errors occur then only the final apply error is
* reported.
*
* Returns 0 on success, a negative error value in case of an error.
* If an apply error occurs, it is returned in *ret_apply.
*/
int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
{
struct of_changeset_entry *ce;
int ret, ret_tmp;
pr_debug("changeset: reverting...\n");
list_for_each_entry_reverse(ce, &ocs->entries, node) {
ret = __of_changeset_entry_revert(ce);
if (ret) {
pr_err("Error reverting changeset (%d)\n", ret);
list_for_each_entry_continue(ce, &ocs->entries, node) {
ret_tmp = __of_changeset_entry_apply(ce);
if (ret_tmp)
*ret_apply = ret_tmp;
}
return ret;
}
}
return 0;
}
/*
* If multiple changeset entry notification errors occur then only the
* final notification error is reported.
*/
int __of_changeset_revert_notify(struct of_changeset *ocs)
{
struct of_changeset_entry *ce;
int ret = 0, ret_tmp;
pr_debug("changeset: emitting notifiers.\n");
/* drop the global lock while emitting notifiers */
mutex_unlock(&of_mutex);
list_for_each_entry_reverse(ce, &ocs->entries, node) {
ret_tmp = __of_changeset_entry_notify(ce, 1);
if (ret_tmp)
ret = ret_tmp;
}
mutex_lock(&of_mutex);
pr_debug("changeset: notifiers sent.\n");
return ret;
}
static int __of_changeset_revert(struct of_changeset *ocs)
{
int ret, ret_reply;
ret_reply = 0;
ret = __of_changeset_revert_entries(ocs, &ret_reply);
if (!ret)
ret = __of_changeset_revert_notify(ocs);
return ret;
}
/**
* of_changeset_revert - Reverts an applied changeset
*
* @ocs: changeset pointer
*
* Reverts a changeset returning the state of the tree to what it
* was before the application.
* Any side-effects like creation/destruction of devices and
* removal of sysfs properties and directories are applied.
* Returns 0 on success, a negative error value in case of an error.
*/
int of_changeset_revert(struct of_changeset *ocs)
{
int ret;
mutex_lock(&of_mutex);
ret = __of_changeset_revert(ocs);
mutex_unlock(&of_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(of_changeset_revert);
/**
* of_changeset_action - Add an action to the tail of the changeset list
*
* @ocs: changeset pointer
* @action: action to perform
* @np: Pointer to device node
* @prop: Pointer to property
*
* On action being one of:
* + OF_RECONFIG_ATTACH_NODE
* + OF_RECONFIG_DETACH_NODE,
* + OF_RECONFIG_ADD_PROPERTY
* + OF_RECONFIG_REMOVE_PROPERTY,
* + OF_RECONFIG_UPDATE_PROPERTY
* Returns 0 on success, a negative error value in case of an error.
*/
int of_changeset_action(struct of_changeset *ocs, unsigned long action,
struct device_node *np, struct property *prop)
{
struct of_changeset_entry *ce;
ce = kzalloc(sizeof(*ce), GFP_KERNEL);
if (!ce)
return -ENOMEM;
/* get a reference to the node */
ce->action = action;
ce->np = of_node_get(np);
ce->prop = prop;
if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
ce->old_prop = of_find_property(np, prop->name, NULL);
/* add it to the list */
list_add_tail(&ce->node, &ocs->entries);
return 0;
}
EXPORT_SYMBOL_GPL(of_changeset_action);