// 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_free_phandle_cache_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; 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; } 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); 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);