/*
 * 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.
 */

#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"

/**
 * 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);

void __of_detach_node_sysfs(struct device_node *np)
{
        struct property *pp;

        if (!IS_ENABLED(CONFIG_SYSFS))
                return;

        BUG_ON(!of_node_is_initialized(np));
        if (!of_kset)
                return;

        /* only remove properties if on sysfs */
        if (of_node_is_attached(np)) {
                for_each_property_of_node(np, pp)
                        sysfs_remove_bin_file(&np->kobj, &pp->attr);
                kobject_del(&np->kobj);
        }

        /* finally remove the kobj_init ref */
        of_node_put(np);
}

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("of/notify %-15s %s\n", action_names[action],
                        pr->dn->full_name);
                break;
        case OF_RECONFIG_ADD_PROPERTY:
        case OF_RECONFIG_REMOVE_PROPERTY:
        case OF_RECONFIG_UPDATE_PROPERTY:
                pr_debug("of/notify %-15s %s:%s\n", action_names[action],
                        pr->dn->full_name, 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);
}

void __of_attach_node(struct device_node *np)
{
        const __be32 *phandle;
        int sz;

        np->name = __of_get_property(np, "name", NULL) ? : "<NULL>";
        np->type = __of_get_property(np, "device_type", NULL) ? : "<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);
        np->phandle = (phandle && (sz >= 4)) ? be32_to_cpup(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);
}

/**
 * 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.
 */
int of_detach_node(struct device_node *np)
{
        struct of_reconfig_data rd;
        unsigned long flags;
        int rc = 0;

        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 rc;
}

/**
 * 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);
        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();
                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_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.
 * @fmt: Format string (plus vargs) for new full name of the device node
 *
 * Create an device tree node, either by duplicating an empty node or by allocating
 * an empty one suitable for further modification.  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 *fmt, ...)
{
        va_list vargs;
        struct device_node *node;

        node = kzalloc(sizeof(*node), GFP_KERNEL);
        if (!node)
                return NULL;
        va_start(vargs, fmt);
        node->full_name = kvasprintf(GFP_KERNEL, fmt, vargs);
        va_end(vargs);
        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)
{
        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("of/cset<%p> %-15s %s/%s\n", ce, action_names[ce->action],
                        ce->np->full_name, ce->prop->name);
                break;
        case OF_RECONFIG_ATTACH_NODE:
        case OF_RECONFIG_DETACH_NODE:
                pr_debug("of/cset<%p> %-15s %s\n", ce, action_names[ce->action],
                        ce->np->full_name);
                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;
                break;
        }
}

static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool revert)
{
        struct of_reconfig_data rd;
        struct of_changeset_entry ce_inverted;
        int ret;

        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("%s: invalid devicetree changeset action: %i\n", __func__,
                        (int)ce->action);
                return;
        }

        if (ret)
                pr_err("%s: notifier error @%s\n", __func__, ce->np->full_name);
}

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("%s: add_property failed @%s/%s\n",
                                __func__, ce->np->full_name,
                                ce->prop->name);
                        break;
                }
                break;
        case OF_RECONFIG_REMOVE_PROPERTY:
                ret = __of_remove_property(ce->np, ce->prop);
                if (ret) {
                        pr_err("%s: remove_property failed @%s/%s\n",
                                __func__, ce->np->full_name,
                                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("%s: update_property failed @%s/%s\n",
                                __func__, ce->np->full_name,
                                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);

int __of_changeset_apply(struct of_changeset *ocs)
{
        struct of_changeset_entry *ce;
        int ret;

        /* perform the rest of the work */
        pr_debug("of_changeset: applying...\n");
        list_for_each_entry(ce, &ocs->entries, node) {
                ret = __of_changeset_entry_apply(ce);
                if (ret) {
                        pr_err("%s: Error applying changeset (%d)\n", __func__, ret);
                        list_for_each_entry_continue_reverse(ce, &ocs->entries, node)
                                __of_changeset_entry_revert(ce);
                        return ret;
                }
        }
        pr_debug("of_changeset: applied, emitting notifiers.\n");

        /* drop the global lock while emitting notifiers */
        mutex_unlock(&of_mutex);
        list_for_each_entry(ce, &ocs->entries, node)
                __of_changeset_entry_notify(ce, 0);
        mutex_lock(&of_mutex);
        pr_debug("of_changeset: notifiers sent.\n");

        return 0;
}

/**
 * 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);

int __of_changeset_revert(struct of_changeset *ocs)
{
        struct of_changeset_entry *ce;
        int ret;

        pr_debug("of_changeset: reverting...\n");
        list_for_each_entry_reverse(ce, &ocs->entries, node) {
                ret = __of_changeset_entry_revert(ce);
                if (ret) {
                        pr_err("%s: Error reverting changeset (%d)\n", __func__, ret);
                        list_for_each_entry_continue(ce, &ocs->entries, node)
                                __of_changeset_entry_apply(ce);
                        return ret;
                }
        }
        pr_debug("of_changeset: reverted, emitting notifiers.\n");

        /* drop the global lock while emitting notifiers */
        mutex_unlock(&of_mutex);
        list_for_each_entry_reverse(ce, &ocs->entries, node)
                __of_changeset_entry_notify(ce, 1);
        mutex_lock(&of_mutex);
        pr_debug("of_changeset: notifiers sent.\n");

        return 0;
}

/**
 * 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 - Perform a changeset action
 *
 * @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) {
                pr_err("%s: Failed to allocate\n", __func__);
                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);