From 201c910bd6898d81d4ac6685d0f421b7e10f3c5d Mon Sep 17 00:00:00 2001 From: Pantelis Antoniou Date: Fri, 4 Jul 2014 19:58:49 +0300 Subject: of: Transactional DT support. Introducing DT transactional support. A DT transaction is a method which allows one to apply changes in the live tree, in such a way that either the full set of changes take effect, or the state of the tree can be rolled-back to the state it was before it was attempted. An applied transaction can be rolled-back at any time. Documentation is in Documentation/devicetree/changesets.txt Signed-off-by: Pantelis Antoniou [glikely: Removed device notifiers and reworked to be more consistent] Signed-off-by: Grant Likely --- drivers/of/dynamic.c | 344 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 344 insertions(+) (limited to 'drivers/of/dynamic.c') diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c index 7bd5501736a6..c1002b7be786 100644 --- a/drivers/of/dynamic.c +++ b/drivers/of/dynamic.c @@ -314,3 +314,347 @@ struct device_node *__of_node_alloc(const char *full_name, gfp_t allocflags) 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; +} -- cgit v1.2.3