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 <pantelis.antoniou@konsulko.com> [glikely: Removed device notifiers and reworked to be more consistent] Signed-off-by: Grant Likely <grant.likely@linaro.org>
This commit is contained in:
Pantelis Antoniou
committed by
Grant Likely
Grant Likely
parent
259092a35c
commit
201c910bd6
@ -314,3 +314,347 @@ struct device_node *__of_node_alloc(const char *full_name, gfp_t allocflags)
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kfree(node);
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return NULL;
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}
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static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
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{
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of_node_put(ce->np);
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list_del(&ce->node);
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kfree(ce);
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}
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#ifdef DEBUG
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static void __of_changeset_entry_dump(struct of_changeset_entry *ce)
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{
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switch (ce->action) {
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case OF_RECONFIG_ADD_PROPERTY:
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pr_debug("%p: %s %s/%s\n",
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ce, "ADD_PROPERTY ", ce->np->full_name,
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ce->prop->name);
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break;
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case OF_RECONFIG_REMOVE_PROPERTY:
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pr_debug("%p: %s %s/%s\n",
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ce, "REMOVE_PROPERTY", ce->np->full_name,
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ce->prop->name);
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break;
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case OF_RECONFIG_UPDATE_PROPERTY:
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pr_debug("%p: %s %s/%s\n",
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ce, "UPDATE_PROPERTY", ce->np->full_name,
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ce->prop->name);
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break;
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case OF_RECONFIG_ATTACH_NODE:
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pr_debug("%p: %s %s\n",
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ce, "ATTACH_NODE ", ce->np->full_name);
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break;
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case OF_RECONFIG_DETACH_NODE:
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pr_debug("%p: %s %s\n",
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ce, "DETACH_NODE ", ce->np->full_name);
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break;
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}
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}
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#else
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static inline void __of_changeset_entry_dump(struct of_changeset_entry *ce)
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{
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/* empty */
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}
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#endif
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static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
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struct of_changeset_entry *rce)
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{
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memcpy(rce, ce, sizeof(*rce));
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switch (ce->action) {
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case OF_RECONFIG_ATTACH_NODE:
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rce->action = OF_RECONFIG_DETACH_NODE;
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break;
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case OF_RECONFIG_DETACH_NODE:
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rce->action = OF_RECONFIG_ATTACH_NODE;
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break;
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case OF_RECONFIG_ADD_PROPERTY:
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rce->action = OF_RECONFIG_REMOVE_PROPERTY;
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break;
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case OF_RECONFIG_REMOVE_PROPERTY:
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rce->action = OF_RECONFIG_ADD_PROPERTY;
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break;
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case OF_RECONFIG_UPDATE_PROPERTY:
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rce->old_prop = ce->prop;
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rce->prop = ce->old_prop;
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break;
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}
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}
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static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool revert)
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{
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struct of_changeset_entry ce_inverted;
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int ret;
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if (revert) {
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__of_changeset_entry_invert(ce, &ce_inverted);
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ce = &ce_inverted;
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}
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switch (ce->action) {
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case OF_RECONFIG_ATTACH_NODE:
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case OF_RECONFIG_DETACH_NODE:
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ret = of_reconfig_notify(ce->action, ce->np);
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break;
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case OF_RECONFIG_ADD_PROPERTY:
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case OF_RECONFIG_REMOVE_PROPERTY:
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case OF_RECONFIG_UPDATE_PROPERTY:
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ret = of_property_notify(ce->action, ce->np, ce->prop, ce->old_prop);
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break;
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default:
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pr_err("%s: invalid devicetree changeset action: %i\n", __func__,
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(int)ce->action);
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return;
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}
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if (ret)
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pr_err("%s: notifier error @%s\n", __func__, ce->np->full_name);
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}
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static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
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{
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struct property *old_prop, **propp;
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unsigned long flags;
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int ret = 0;
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__of_changeset_entry_dump(ce);
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raw_spin_lock_irqsave(&devtree_lock, flags);
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switch (ce->action) {
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case OF_RECONFIG_ATTACH_NODE:
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__of_attach_node(ce->np);
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break;
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case OF_RECONFIG_DETACH_NODE:
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__of_detach_node(ce->np);
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break;
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case OF_RECONFIG_ADD_PROPERTY:
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/* If the property is in deadprops then it must be removed */
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for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
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if (*propp == ce->prop) {
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*propp = ce->prop->next;
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ce->prop->next = NULL;
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break;
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}
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}
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ret = __of_add_property(ce->np, ce->prop);
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if (ret) {
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pr_err("%s: add_property failed @%s/%s\n",
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__func__, ce->np->full_name,
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ce->prop->name);
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break;
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}
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break;
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case OF_RECONFIG_REMOVE_PROPERTY:
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ret = __of_remove_property(ce->np, ce->prop);
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if (ret) {
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pr_err("%s: remove_property failed @%s/%s\n",
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__func__, ce->np->full_name,
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ce->prop->name);
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break;
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}
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break;
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case OF_RECONFIG_UPDATE_PROPERTY:
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/* If the property is in deadprops then it must be removed */
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for (propp = &ce->np->deadprops; *propp; propp = &(*propp)->next) {
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if (*propp == ce->prop) {
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*propp = ce->prop->next;
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ce->prop->next = NULL;
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break;
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}
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}
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ret = __of_update_property(ce->np, ce->prop, &old_prop);
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if (ret) {
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pr_err("%s: update_property failed @%s/%s\n",
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__func__, ce->np->full_name,
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ce->prop->name);
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break;
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}
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break;
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default:
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ret = -EINVAL;
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}
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raw_spin_unlock_irqrestore(&devtree_lock, flags);
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if (ret)
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return ret;
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switch (ce->action) {
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case OF_RECONFIG_ATTACH_NODE:
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__of_attach_node_sysfs(ce->np);
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break;
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case OF_RECONFIG_DETACH_NODE:
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__of_detach_node_sysfs(ce->np);
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break;
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case OF_RECONFIG_ADD_PROPERTY:
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/* ignore duplicate names */
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__of_add_property_sysfs(ce->np, ce->prop);
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break;
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case OF_RECONFIG_REMOVE_PROPERTY:
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__of_remove_property_sysfs(ce->np, ce->prop);
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break;
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case OF_RECONFIG_UPDATE_PROPERTY:
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__of_update_property_sysfs(ce->np, ce->prop, ce->old_prop);
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break;
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}
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return 0;
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}
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static inline int __of_changeset_entry_revert(struct of_changeset_entry *ce)
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{
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struct of_changeset_entry ce_inverted;
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__of_changeset_entry_invert(ce, &ce_inverted);
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return __of_changeset_entry_apply(&ce_inverted);
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}
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/**
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* of_changeset_init - Initialize a changeset for use
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*
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* @ocs: changeset pointer
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*
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* Initialize a changeset structure
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*/
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void of_changeset_init(struct of_changeset *ocs)
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{
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memset(ocs, 0, sizeof(*ocs));
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INIT_LIST_HEAD(&ocs->entries);
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}
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/**
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* of_changeset_destroy - Destroy a changeset
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*
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* @ocs: changeset pointer
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*
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* Destroys a changeset. Note that if a changeset is applied,
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* its changes to the tree cannot be reverted.
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*/
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void of_changeset_destroy(struct of_changeset *ocs)
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{
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struct of_changeset_entry *ce, *cen;
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list_for_each_entry_safe_reverse(ce, cen, &ocs->entries, node)
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__of_changeset_entry_destroy(ce);
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}
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/**
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* of_changeset_apply - Applies a changeset
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*
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* @ocs: changeset pointer
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*
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* Applies a changeset to the live tree.
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* Any side-effects of live tree state changes are applied here on
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* sucess, like creation/destruction of devices and side-effects
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* like creation of sysfs properties and directories.
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* Returns 0 on success, a negative error value in case of an error.
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* On error the partially applied effects are reverted.
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*/
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int of_changeset_apply(struct of_changeset *ocs)
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{
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struct of_changeset_entry *ce;
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int ret;
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/* perform the rest of the work */
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pr_debug("of_changeset: applying...\n");
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list_for_each_entry(ce, &ocs->entries, node) {
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ret = __of_changeset_entry_apply(ce);
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if (ret) {
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pr_err("%s: Error applying changeset (%d)\n", __func__, ret);
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list_for_each_entry_continue_reverse(ce, &ocs->entries, node)
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__of_changeset_entry_revert(ce);
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return ret;
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}
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}
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pr_debug("of_changeset: applied, emitting notifiers.\n");
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/* drop the global lock while emitting notifiers */
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mutex_unlock(&of_mutex);
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list_for_each_entry(ce, &ocs->entries, node)
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__of_changeset_entry_notify(ce, 0);
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mutex_lock(&of_mutex);
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pr_debug("of_changeset: notifiers sent.\n");
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return 0;
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}
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/**
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* of_changeset_revert - Reverts an applied changeset
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*
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* @ocs: changeset pointer
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*
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* Reverts a changeset returning the state of the tree to what it
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* was before the application.
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* Any side-effects like creation/destruction of devices and
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* removal of sysfs properties and directories are applied.
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* Returns 0 on success, a negative error value in case of an error.
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*/
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int of_changeset_revert(struct of_changeset *ocs)
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{
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struct of_changeset_entry *ce;
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int ret;
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pr_debug("of_changeset: reverting...\n");
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list_for_each_entry_reverse(ce, &ocs->entries, node) {
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ret = __of_changeset_entry_revert(ce);
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if (ret) {
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pr_err("%s: Error reverting changeset (%d)\n", __func__, ret);
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list_for_each_entry_continue(ce, &ocs->entries, node)
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__of_changeset_entry_apply(ce);
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return ret;
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}
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}
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pr_debug("of_changeset: reverted, emitting notifiers.\n");
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/* drop the global lock while emitting notifiers */
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mutex_unlock(&of_mutex);
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list_for_each_entry_reverse(ce, &ocs->entries, node)
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__of_changeset_entry_notify(ce, 1);
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mutex_lock(&of_mutex);
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pr_debug("of_changeset: notifiers sent.\n");
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return 0;
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}
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/**
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* of_changeset_action - Perform a changeset action
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*
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* @ocs: changeset pointer
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* @action: action to perform
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* @np: Pointer to device node
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* @prop: Pointer to property
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*
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* On action being one of:
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* + OF_RECONFIG_ATTACH_NODE
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* + OF_RECONFIG_DETACH_NODE,
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* + OF_RECONFIG_ADD_PROPERTY
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* + OF_RECONFIG_REMOVE_PROPERTY,
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* + OF_RECONFIG_UPDATE_PROPERTY
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* Returns 0 on success, a negative error value in case of an error.
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*/
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int of_changeset_action(struct of_changeset *ocs, unsigned long action,
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struct device_node *np, struct property *prop)
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{
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struct of_changeset_entry *ce;
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ce = kzalloc(sizeof(*ce), GFP_KERNEL);
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if (!ce) {
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pr_err("%s: Failed to allocate\n", __func__);
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return -ENOMEM;
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}
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/* get a reference to the node */
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ce->action = action;
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ce->np = of_node_get(np);
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ce->prop = prop;
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if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
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ce->old_prop = of_find_property(np, prop->name, NULL);
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/* add it to the list */
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list_add_tail(&ce->node, &ocs->entries);
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return 0;
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}
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