diff options
Diffstat (limited to 'drivers/of/dynamic.c')
| -rw-r--r-- | drivers/of/dynamic.c | 660 |
1 files changed, 660 insertions, 0 deletions
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c new file mode 100644 index 000000000000..54fecc49a1fe --- /dev/null +++ b/drivers/of/dynamic.c @@ -0,0 +1,660 @@ +/* + * 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; + + 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); + +int of_reconfig_notify(unsigned long action, void *p) +{ + int rc; + + rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p); + return notifier_to_errno(rc); +} + +int of_property_notify(int action, struct device_node *np, + struct property *prop, struct property *oldprop) +{ + struct of_prop_reconfig 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(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->allnext = np->parent->allnext; + np->parent->allnext = np; + 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) +{ + unsigned long flags; + + 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, np); + + 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 (of_allnodes == np) + of_allnodes = np->allnext; + else { + struct device_node *prev; + for (prev = of_allnodes; + prev->allnext != np; + prev = prev->allnext) + ; + prev->allnext = np->allnext; + } + + 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) +{ + unsigned long flags; + int rc = 0; + + 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, np); + + 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 stucture 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_alloc() - Create an empty device node dynamically. + * @full_name: Full name of the new device node + * @allocflags: Allocation flags (typically pass GFP_KERNEL) + * + * Create an empty device tree node, 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_alloc(const char *full_name, gfp_t allocflags) +{ + struct device_node *node; + + node = kzalloc(sizeof(*node), allocflags); + if (!node) + return NULL; + + node->full_name = kstrdup(full_name, allocflags); + of_node_set_flag(node, OF_DYNAMIC); + of_node_set_flag(node, OF_DETACHED); + if (!node->full_name) + goto err_free; + + of_node_init(node); + + return node; + + err_free: + kfree(node->full_name); + kfree(node); + 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: + pr_debug("%p: %s %s/%s\n", + ce, "ADD_PROPERTY ", ce->np->full_name, + ce->prop->name); + break; + case OF_RECONFIG_REMOVE_PROPERTY: + pr_debug("%p: %s %s/%s\n", + ce, "REMOVE_PROPERTY", ce->np->full_name, + ce->prop->name); + break; + case OF_RECONFIG_UPDATE_PROPERTY: + pr_debug("%p: %s %s/%s\n", + ce, "UPDATE_PROPERTY", ce->np->full_name, + ce->prop->name); + break; + case OF_RECONFIG_ATTACH_NODE: + pr_debug("%p: %s %s\n", + ce, "ATTACH_NODE ", ce->np->full_name); + break; + case OF_RECONFIG_DETACH_NODE: + pr_debug("%p: %s %s\n", + ce, "DETACH_NODE ", 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_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: + ret = of_reconfig_notify(ce->action, ce->np); + 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); +} + +/** + * 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); +} + +/** + * 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 + * sucess, 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) +{ + 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_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) +{ + 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_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; +} |