diff options
Diffstat (limited to 'drivers/of/dynamic.c')
| -rw-r--r-- | drivers/of/dynamic.c | 925 |
1 files changed, 925 insertions, 0 deletions
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c new file mode 100644 index 000000000..9bb9fe0fa --- /dev/null +++ b/drivers/of/dynamic.c @@ -0,0 +1,925 @@ +// 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 + * + * Return: The node with refcount incremented. + */ +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); + +static const char *action_names[] = { + [0] = "INVALID", + [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", +}; + +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. + * + * Return: OF_RECONFIG_CHANGE_REMOVE on device going from enabled to + * disabled, OF_RECONFIG_CHANGE_ADD on device going from disabled to + * enabled and OF_RECONFIG_NO_CHANGE 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); + np->fwnode.flags |= FWNODE_FLAG_NOT_DEVICE; +} + +/** + * of_attach_node() - Plug a device node into the tree and global list. + * @np: Pointer to the caller's Device Node + */ +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. + * @np: Pointer to the caller's Device Node + */ +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 + * @kobj: kernel object 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. + * + * Return: 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. + * + * Return: 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); + break; + case OF_RECONFIG_REMOVE_PROPERTY: + ret = __of_remove_property(ce->np, ce->prop); + 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); + break; + default: + ret = -EINVAL; + } + raw_spin_unlock_irqrestore(&devtree_lock, flags); + + if (ret) { + pr_err("changeset: apply failed: %-15s %pOF:%s\n", + action_names[ce->action], ce->np, ce->prop->name); + 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. + * + * Return: 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. + * + * Return: 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 + * + * Return: 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; + + if (WARN_ON(action >= ARRAY_SIZE(action_names))) + return -EINVAL; + + 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); |