981 строка
25 KiB
C
981 строка
25 KiB
C
/*
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* Functions for working with device tree overlays
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*
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* Copyright (C) 2012 Pantelis Antoniou <panto@antoniou-consulting.com>
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* Copyright (C) 2012 Texas Instruments Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*/
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#define pr_fmt(fmt) "OF: overlay: " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/string.h>
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#include <linux/ctype.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/idr.h>
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#include "of_private.h"
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/**
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* struct fragment - info about fragment nodes in overlay expanded device tree
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* @target: target of the overlay operation
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* @overlay: pointer to the __overlay__ node
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*/
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struct fragment {
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struct device_node *target;
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struct device_node *overlay;
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};
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/**
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* struct overlay_changeset
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* @ovcs_list: list on which we are located
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* @overlay_tree: expanded device tree that contains the fragment nodes
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* @count: count of fragment structures
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* @fragments: fragment nodes in the overlay expanded device tree
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* @symbols_fragment: last element of @fragments[] is the __symbols__ node
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* @cset: changeset to apply fragments to live device tree
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*/
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struct overlay_changeset {
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int id;
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struct list_head ovcs_list;
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struct device_node *overlay_tree;
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int count;
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struct fragment *fragments;
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bool symbols_fragment;
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struct of_changeset cset;
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};
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/* flags are sticky - once set, do not reset */
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static int devicetree_state_flags;
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#define DTSF_APPLY_FAIL 0x01
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#define DTSF_REVERT_FAIL 0x02
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/*
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* If a changeset apply or revert encounters an error, an attempt will
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* be made to undo partial changes, but may fail. If the undo fails
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* we do not know the state of the devicetree.
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*/
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static int devicetree_corrupt(void)
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{
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return devicetree_state_flags &
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(DTSF_APPLY_FAIL | DTSF_REVERT_FAIL);
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}
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static int build_changeset_next_level(struct overlay_changeset *ovcs,
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struct device_node *target_node,
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const struct device_node *overlay_node);
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/*
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* of_resolve_phandles() finds the largest phandle in the live tree.
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* of_overlay_apply() may add a larger phandle to the live tree.
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* Do not allow race between two overlays being applied simultaneously:
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* mutex_lock(&of_overlay_phandle_mutex)
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* of_resolve_phandles()
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* of_overlay_apply()
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* mutex_unlock(&of_overlay_phandle_mutex)
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*/
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static DEFINE_MUTEX(of_overlay_phandle_mutex);
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void of_overlay_mutex_lock(void)
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{
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mutex_lock(&of_overlay_phandle_mutex);
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}
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void of_overlay_mutex_unlock(void)
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{
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mutex_unlock(&of_overlay_phandle_mutex);
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}
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static LIST_HEAD(ovcs_list);
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static DEFINE_IDR(ovcs_idr);
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static BLOCKING_NOTIFIER_HEAD(overlay_notify_chain);
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int of_overlay_notifier_register(struct notifier_block *nb)
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{
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return blocking_notifier_chain_register(&overlay_notify_chain, nb);
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}
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EXPORT_SYMBOL_GPL(of_overlay_notifier_register);
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int of_overlay_notifier_unregister(struct notifier_block *nb)
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{
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return blocking_notifier_chain_unregister(&overlay_notify_chain, nb);
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}
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EXPORT_SYMBOL_GPL(of_overlay_notifier_unregister);
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static char *of_overlay_action_name[] = {
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"pre-apply",
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"post-apply",
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"pre-remove",
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"post-remove",
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};
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static int overlay_notify(struct overlay_changeset *ovcs,
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enum of_overlay_notify_action action)
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{
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struct of_overlay_notify_data nd;
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int i, ret;
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for (i = 0; i < ovcs->count; i++) {
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struct fragment *fragment = &ovcs->fragments[i];
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nd.target = fragment->target;
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nd.overlay = fragment->overlay;
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ret = blocking_notifier_call_chain(&overlay_notify_chain,
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action, &nd);
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if (ret == NOTIFY_OK || ret == NOTIFY_STOP)
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return 0;
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if (ret) {
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ret = notifier_to_errno(ret);
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pr_err("overlay changeset %s notifier error %d, target: %pOF\n",
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of_overlay_action_name[action], ret, nd.target);
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return ret;
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}
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}
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return 0;
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}
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/*
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* The values of properties in the "/__symbols__" node are paths in
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* the ovcs->overlay_tree. When duplicating the properties, the paths
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* need to be adjusted to be the correct path for the live device tree.
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*
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* The paths refer to a node in the subtree of a fragment node's "__overlay__"
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* node, for example "/fragment@0/__overlay__/symbol_path_tail",
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* where symbol_path_tail can be a single node or it may be a multi-node path.
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*
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* The duplicated property value will be modified by replacing the
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* "/fragment_name/__overlay/" portion of the value with the target
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* path from the fragment node.
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*/
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static struct property *dup_and_fixup_symbol_prop(
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struct overlay_changeset *ovcs, const struct property *prop)
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{
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struct fragment *fragment;
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struct property *new_prop;
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struct device_node *fragment_node;
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struct device_node *overlay_node;
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const char *path;
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const char *path_tail;
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const char *target_path;
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int k;
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int overlay_name_len;
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int path_len;
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int path_tail_len;
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int target_path_len;
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if (!prop->value)
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return NULL;
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if (strnlen(prop->value, prop->length) >= prop->length)
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return NULL;
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path = prop->value;
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path_len = strlen(path);
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if (path_len < 1)
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return NULL;
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fragment_node = __of_find_node_by_path(ovcs->overlay_tree, path + 1);
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overlay_node = __of_find_node_by_path(fragment_node, "__overlay__/");
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of_node_put(fragment_node);
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of_node_put(overlay_node);
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for (k = 0; k < ovcs->count; k++) {
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fragment = &ovcs->fragments[k];
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if (fragment->overlay == overlay_node)
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break;
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}
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if (k >= ovcs->count)
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return NULL;
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overlay_name_len = snprintf(NULL, 0, "%pOF", fragment->overlay);
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if (overlay_name_len > path_len)
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return NULL;
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path_tail = path + overlay_name_len;
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path_tail_len = strlen(path_tail);
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target_path = kasprintf(GFP_KERNEL, "%pOF", fragment->target);
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if (!target_path)
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return NULL;
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target_path_len = strlen(target_path);
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new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
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if (!new_prop)
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goto err_free_target_path;
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new_prop->name = kstrdup(prop->name, GFP_KERNEL);
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new_prop->length = target_path_len + path_tail_len + 1;
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new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
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if (!new_prop->name || !new_prop->value)
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goto err_free_new_prop;
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strcpy(new_prop->value, target_path);
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strcpy(new_prop->value + target_path_len, path_tail);
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of_property_set_flag(new_prop, OF_DYNAMIC);
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return new_prop;
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err_free_new_prop:
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kfree(new_prop->name);
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kfree(new_prop->value);
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kfree(new_prop);
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err_free_target_path:
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kfree(target_path);
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return NULL;
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}
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/**
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* add_changeset_property() - add @overlay_prop to overlay changeset
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* @ovcs: overlay changeset
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* @target_node: where to place @overlay_prop in live tree
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* @overlay_prop: property to add or update, from overlay tree
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* @is_symbols_prop: 1 if @overlay_prop is from node "/__symbols__"
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*
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* If @overlay_prop does not already exist in @target_node, add changeset entry
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* to add @overlay_prop in @target_node, else add changeset entry to update
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* value of @overlay_prop.
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*
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* Some special properties are not updated (no error returned).
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*
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* Update of property in symbols node is not allowed.
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*
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* Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
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* invalid @overlay.
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*/
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static int add_changeset_property(struct overlay_changeset *ovcs,
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struct device_node *target_node,
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struct property *overlay_prop,
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bool is_symbols_prop)
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{
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struct property *new_prop = NULL, *prop;
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int ret = 0;
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prop = of_find_property(target_node, overlay_prop->name, NULL);
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if (!of_prop_cmp(overlay_prop->name, "name") ||
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!of_prop_cmp(overlay_prop->name, "phandle") ||
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!of_prop_cmp(overlay_prop->name, "linux,phandle"))
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return 0;
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if (is_symbols_prop) {
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if (prop)
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return -EINVAL;
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new_prop = dup_and_fixup_symbol_prop(ovcs, overlay_prop);
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} else {
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new_prop = __of_prop_dup(overlay_prop, GFP_KERNEL);
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}
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if (!new_prop)
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return -ENOMEM;
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if (!prop)
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ret = of_changeset_add_property(&ovcs->cset, target_node,
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new_prop);
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else
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ret = of_changeset_update_property(&ovcs->cset, target_node,
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new_prop);
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if (ret) {
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kfree(new_prop->name);
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kfree(new_prop->value);
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kfree(new_prop);
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}
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return ret;
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}
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/**
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* add_changeset_node() - add @node (and children) to overlay changeset
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* @ovcs: overlay changeset
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* @target_node: where to place @node in live tree
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* @node: node from within overlay device tree fragment
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*
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* If @node does not already exist in @target_node, add changeset entry
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* to add @node in @target_node.
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*
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* If @node already exists in @target_node, and the existing node has
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* a phandle, the overlay node is not allowed to have a phandle.
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*
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* If @node has child nodes, add the children recursively via
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* build_changeset_next_level().
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*
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* NOTE: Multiple mods of created nodes not supported.
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* If more than one fragment contains a node that does not already exist
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* in the live tree, then for each fragment of_changeset_attach_node()
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* will add a changeset entry to add the node. When the changeset is
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* applied, __of_attach_node() will attach the node twice (once for
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* each fragment). At this point the device tree will be corrupted.
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*
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* TODO: add integrity check to ensure that multiple fragments do not
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* create the same node.
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*
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* Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
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* invalid @overlay.
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*/
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static int add_changeset_node(struct overlay_changeset *ovcs,
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struct device_node *target_node, struct device_node *node)
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{
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const char *node_kbasename;
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struct device_node *tchild;
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int ret = 0;
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node_kbasename = kbasename(node->full_name);
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for_each_child_of_node(target_node, tchild)
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if (!of_node_cmp(node_kbasename, kbasename(tchild->full_name)))
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break;
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if (!tchild) {
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tchild = __of_node_dup(node, "%pOF/%s",
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target_node, node_kbasename);
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if (!tchild)
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return -ENOMEM;
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tchild->parent = target_node;
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ret = of_changeset_attach_node(&ovcs->cset, tchild);
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if (ret)
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return ret;
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return build_changeset_next_level(ovcs, tchild, node);
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}
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if (node->phandle && tchild->phandle)
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ret = -EINVAL;
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else
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ret = build_changeset_next_level(ovcs, tchild, node);
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of_node_put(tchild);
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return ret;
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}
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/**
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* build_changeset_next_level() - add level of overlay changeset
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* @ovcs: overlay changeset
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* @target_node: where to place @overlay_node in live tree
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* @overlay_node: node from within an overlay device tree fragment
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*
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* Add the properties (if any) and nodes (if any) from @overlay_node to the
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* @ovcs->cset changeset. If an added node has child nodes, they will
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* be added recursively.
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*
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* Do not allow symbols node to have any children.
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*
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* Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
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* invalid @overlay_node.
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*/
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static int build_changeset_next_level(struct overlay_changeset *ovcs,
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struct device_node *target_node,
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const struct device_node *overlay_node)
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{
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struct device_node *child;
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struct property *prop;
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int ret;
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for_each_property_of_node(overlay_node, prop) {
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ret = add_changeset_property(ovcs, target_node, prop, 0);
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if (ret) {
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pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
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target_node, prop->name, ret);
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return ret;
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}
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}
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for_each_child_of_node(overlay_node, child) {
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ret = add_changeset_node(ovcs, target_node, child);
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if (ret) {
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pr_debug("Failed to apply node @%pOF/%s, err=%d\n",
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target_node, child->name, ret);
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of_node_put(child);
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return ret;
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}
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}
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return 0;
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}
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/*
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* Add the properties from __overlay__ node to the @ovcs->cset changeset.
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*/
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static int build_changeset_symbols_node(struct overlay_changeset *ovcs,
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struct device_node *target_node,
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const struct device_node *overlay_symbols_node)
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{
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struct property *prop;
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int ret;
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for_each_property_of_node(overlay_symbols_node, prop) {
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ret = add_changeset_property(ovcs, target_node, prop, 1);
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if (ret) {
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pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
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target_node, prop->name, ret);
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return ret;
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}
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}
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return 0;
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}
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/**
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* build_changeset() - populate overlay changeset in @ovcs from @ovcs->fragments
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* @ovcs: Overlay changeset
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*
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* Create changeset @ovcs->cset to contain the nodes and properties of the
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* overlay device tree fragments in @ovcs->fragments[]. If an error occurs,
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* any portions of the changeset that were successfully created will remain
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* in @ovcs->cset.
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*
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* Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
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* invalid overlay in @ovcs->fragments[].
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*/
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static int build_changeset(struct overlay_changeset *ovcs)
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{
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struct fragment *fragment;
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int fragments_count, i, ret;
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/*
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* if there is a symbols fragment in ovcs->fragments[i] it is
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* the final element in the array
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*/
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if (ovcs->symbols_fragment)
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fragments_count = ovcs->count - 1;
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else
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fragments_count = ovcs->count;
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for (i = 0; i < fragments_count; i++) {
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fragment = &ovcs->fragments[i];
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ret = build_changeset_next_level(ovcs, fragment->target,
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fragment->overlay);
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if (ret) {
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pr_debug("apply failed '%pOF'\n", fragment->target);
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return ret;
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}
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}
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if (ovcs->symbols_fragment) {
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fragment = &ovcs->fragments[ovcs->count - 1];
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ret = build_changeset_symbols_node(ovcs, fragment->target,
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fragment->overlay);
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if (ret) {
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pr_debug("apply failed '%pOF'\n", fragment->target);
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return ret;
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}
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}
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return 0;
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}
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/*
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* Find the target node using a number of different strategies
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* in order of preference:
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*
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* 1) "target" property containing the phandle of the target
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* 2) "target-path" property containing the path of the target
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*/
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static struct device_node *find_target_node(struct device_node *info_node)
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{
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const char *path;
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u32 val;
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int ret;
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ret = of_property_read_u32(info_node, "target", &val);
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if (!ret)
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return of_find_node_by_phandle(val);
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ret = of_property_read_string(info_node, "target-path", &path);
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if (!ret)
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return of_find_node_by_path(path);
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pr_err("Failed to find target for node %p (%s)\n",
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info_node, info_node->name);
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return NULL;
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}
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/**
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* init_overlay_changeset() - initialize overlay changeset from overlay tree
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* @ovcs Overlay changeset to build
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* @tree: Contains all the overlay fragments and overlay fixup nodes
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*
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* Initialize @ovcs. Populate @ovcs->fragments with node information from
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* the top level of @tree. The relevant top level nodes are the fragment
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* nodes and the __symbols__ node. Any other top level node will be ignored.
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*
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* Returns 0 on success, -ENOMEM if memory allocation failure, -EINVAL if error
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* detected in @tree, or -ENOSPC if idr_alloc() error.
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*/
|
|
static int init_overlay_changeset(struct overlay_changeset *ovcs,
|
|
struct device_node *tree)
|
|
{
|
|
struct device_node *node, *overlay_node;
|
|
struct fragment *fragment;
|
|
struct fragment *fragments;
|
|
int cnt, id, ret;
|
|
|
|
/*
|
|
* Warn for some issues. Can not return -EINVAL for these until
|
|
* of_unittest_apply_overlay() is fixed to pass these checks.
|
|
*/
|
|
if (!of_node_check_flag(tree, OF_DYNAMIC))
|
|
pr_debug("%s() tree is not dynamic\n", __func__);
|
|
|
|
if (!of_node_check_flag(tree, OF_DETACHED))
|
|
pr_debug("%s() tree is not detached\n", __func__);
|
|
|
|
if (!of_node_is_root(tree))
|
|
pr_debug("%s() tree is not root\n", __func__);
|
|
|
|
ovcs->overlay_tree = tree;
|
|
|
|
INIT_LIST_HEAD(&ovcs->ovcs_list);
|
|
|
|
of_changeset_init(&ovcs->cset);
|
|
|
|
id = idr_alloc(&ovcs_idr, ovcs, 1, 0, GFP_KERNEL);
|
|
if (id <= 0)
|
|
return id;
|
|
|
|
cnt = 0;
|
|
|
|
/* fragment nodes */
|
|
for_each_child_of_node(tree, node) {
|
|
overlay_node = of_get_child_by_name(node, "__overlay__");
|
|
if (overlay_node) {
|
|
cnt++;
|
|
of_node_put(overlay_node);
|
|
}
|
|
}
|
|
|
|
node = of_get_child_by_name(tree, "__symbols__");
|
|
if (node) {
|
|
cnt++;
|
|
of_node_put(node);
|
|
}
|
|
|
|
fragments = kcalloc(cnt, sizeof(*fragments), GFP_KERNEL);
|
|
if (!fragments) {
|
|
ret = -ENOMEM;
|
|
goto err_free_idr;
|
|
}
|
|
|
|
cnt = 0;
|
|
for_each_child_of_node(tree, node) {
|
|
overlay_node = of_get_child_by_name(node, "__overlay__");
|
|
if (!overlay_node)
|
|
continue;
|
|
|
|
fragment = &fragments[cnt];
|
|
fragment->overlay = overlay_node;
|
|
fragment->target = find_target_node(node);
|
|
if (!fragment->target) {
|
|
of_node_put(fragment->overlay);
|
|
ret = -EINVAL;
|
|
goto err_free_fragments;
|
|
}
|
|
|
|
cnt++;
|
|
}
|
|
|
|
/*
|
|
* if there is a symbols fragment in ovcs->fragments[i] it is
|
|
* the final element in the array
|
|
*/
|
|
node = of_get_child_by_name(tree, "__symbols__");
|
|
if (node) {
|
|
ovcs->symbols_fragment = 1;
|
|
fragment = &fragments[cnt];
|
|
fragment->overlay = node;
|
|
fragment->target = of_find_node_by_path("/__symbols__");
|
|
|
|
if (!fragment->target) {
|
|
pr_err("symbols in overlay, but not in live tree\n");
|
|
ret = -EINVAL;
|
|
goto err_free_fragments;
|
|
}
|
|
|
|
cnt++;
|
|
}
|
|
|
|
if (!cnt) {
|
|
ret = -EINVAL;
|
|
goto err_free_fragments;
|
|
}
|
|
|
|
ovcs->id = id;
|
|
ovcs->count = cnt;
|
|
ovcs->fragments = fragments;
|
|
|
|
return 0;
|
|
|
|
err_free_fragments:
|
|
kfree(fragments);
|
|
err_free_idr:
|
|
idr_remove(&ovcs_idr, id);
|
|
|
|
pr_err("%s() failed, ret = %d\n", __func__, ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void free_overlay_changeset(struct overlay_changeset *ovcs)
|
|
{
|
|
int i;
|
|
|
|
if (ovcs->cset.entries.next)
|
|
of_changeset_destroy(&ovcs->cset);
|
|
|
|
if (ovcs->id)
|
|
idr_remove(&ovcs_idr, ovcs->id);
|
|
|
|
for (i = 0; i < ovcs->count; i++) {
|
|
of_node_put(ovcs->fragments[i].target);
|
|
of_node_put(ovcs->fragments[i].overlay);
|
|
}
|
|
kfree(ovcs->fragments);
|
|
|
|
kfree(ovcs);
|
|
}
|
|
|
|
/**
|
|
* of_overlay_apply() - Create and apply an overlay changeset
|
|
* @tree: Expanded overlay device tree
|
|
* @ovcs_id: Pointer to overlay changeset id
|
|
*
|
|
* Creates and applies an overlay changeset.
|
|
*
|
|
* If an error occurs in a pre-apply notifier, then no changes are made
|
|
* to the device tree.
|
|
*
|
|
|
|
* A non-zero return value will not have created the changeset if error is from:
|
|
* - parameter checks
|
|
* - building the changeset
|
|
* - overlay changeset pre-apply notifier
|
|
*
|
|
* If an error is returned by an overlay changeset pre-apply notifier
|
|
* then no further overlay changeset pre-apply notifier will be called.
|
|
*
|
|
* A non-zero return value will have created the changeset if error is from:
|
|
* - overlay changeset entry notifier
|
|
* - overlay changeset post-apply notifier
|
|
*
|
|
* If an error is returned by an overlay changeset post-apply notifier
|
|
* then no further overlay changeset post-apply notifier will be called.
|
|
*
|
|
* If more than one notifier returns an error, then the last notifier
|
|
* error to occur is returned.
|
|
*
|
|
* If an error occurred while applying the overlay changeset, then an
|
|
* attempt is made to revert any changes that were made to the
|
|
* device tree. If there were any errors during the revert attempt
|
|
* then the state of the device tree can not be determined, and any
|
|
* following attempt to apply or remove an overlay changeset will be
|
|
* refused.
|
|
*
|
|
* Returns 0 on success, or a negative error number. Overlay changeset
|
|
* id is returned to *ovcs_id.
|
|
*/
|
|
|
|
int of_overlay_apply(struct device_node *tree, int *ovcs_id)
|
|
{
|
|
struct overlay_changeset *ovcs;
|
|
int ret = 0, ret_revert, ret_tmp;
|
|
|
|
*ovcs_id = 0;
|
|
|
|
if (devicetree_corrupt()) {
|
|
pr_err("devicetree state suspect, refuse to apply overlay\n");
|
|
ret = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
ovcs = kzalloc(sizeof(*ovcs), GFP_KERNEL);
|
|
if (!ovcs) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
of_overlay_mutex_lock();
|
|
mutex_lock(&of_mutex);
|
|
|
|
ret = of_resolve_phandles(tree);
|
|
if (ret)
|
|
goto err_free_overlay_changeset;
|
|
|
|
ret = init_overlay_changeset(ovcs, tree);
|
|
if (ret)
|
|
goto err_free_overlay_changeset;
|
|
|
|
ret = overlay_notify(ovcs, OF_OVERLAY_PRE_APPLY);
|
|
if (ret) {
|
|
pr_err("overlay changeset pre-apply notify error %d\n", ret);
|
|
goto err_free_overlay_changeset;
|
|
}
|
|
|
|
ret = build_changeset(ovcs);
|
|
if (ret)
|
|
goto err_free_overlay_changeset;
|
|
|
|
ret_revert = 0;
|
|
ret = __of_changeset_apply_entries(&ovcs->cset, &ret_revert);
|
|
if (ret) {
|
|
if (ret_revert) {
|
|
pr_debug("overlay changeset revert error %d\n",
|
|
ret_revert);
|
|
devicetree_state_flags |= DTSF_APPLY_FAIL;
|
|
}
|
|
goto err_free_overlay_changeset;
|
|
}
|
|
|
|
ret = __of_changeset_apply_notify(&ovcs->cset);
|
|
if (ret)
|
|
pr_err("overlay changeset entry notify error %d\n", ret);
|
|
/* notify failure is not fatal, continue */
|
|
|
|
list_add_tail(&ovcs->ovcs_list, &ovcs_list);
|
|
*ovcs_id = ovcs->id;
|
|
|
|
ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_APPLY);
|
|
if (ret_tmp) {
|
|
pr_err("overlay changeset post-apply notify error %d\n",
|
|
ret_tmp);
|
|
if (!ret)
|
|
ret = ret_tmp;
|
|
}
|
|
|
|
goto out_unlock;
|
|
|
|
err_free_overlay_changeset:
|
|
free_overlay_changeset(ovcs);
|
|
|
|
out_unlock:
|
|
mutex_unlock(&of_mutex);
|
|
of_overlay_mutex_unlock();
|
|
|
|
out:
|
|
pr_debug("%s() err=%d\n", __func__, ret);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_overlay_apply);
|
|
|
|
/*
|
|
* Find @np in @tree.
|
|
*
|
|
* Returns 1 if @np is @tree or is contained in @tree, else 0
|
|
*/
|
|
static int find_node(struct device_node *tree, struct device_node *np)
|
|
{
|
|
struct device_node *child;
|
|
|
|
if (tree == np)
|
|
return 1;
|
|
|
|
for_each_child_of_node(tree, child) {
|
|
if (find_node(child, np)) {
|
|
of_node_put(child);
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Is @remove_ce_node a child of, a parent of, or the same as any
|
|
* node in an overlay changeset more topmost than @remove_ovcs?
|
|
*
|
|
* Returns 1 if found, else 0
|
|
*/
|
|
static int node_overlaps_later_cs(struct overlay_changeset *remove_ovcs,
|
|
struct device_node *remove_ce_node)
|
|
{
|
|
struct overlay_changeset *ovcs;
|
|
struct of_changeset_entry *ce;
|
|
|
|
list_for_each_entry_reverse(ovcs, &ovcs_list, ovcs_list) {
|
|
if (ovcs == remove_ovcs)
|
|
break;
|
|
|
|
list_for_each_entry(ce, &ovcs->cset.entries, node) {
|
|
if (find_node(ce->np, remove_ce_node)) {
|
|
pr_err("%s: #%d overlaps with #%d @%pOF\n",
|
|
__func__, remove_ovcs->id, ovcs->id,
|
|
remove_ce_node);
|
|
return 1;
|
|
}
|
|
if (find_node(remove_ce_node, ce->np)) {
|
|
pr_err("%s: #%d overlaps with #%d @%pOF\n",
|
|
__func__, remove_ovcs->id, ovcs->id,
|
|
remove_ce_node);
|
|
return 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* We can safely remove the overlay only if it's the top-most one.
|
|
* Newly applied overlays are inserted at the tail of the overlay list,
|
|
* so a top most overlay is the one that is closest to the tail.
|
|
*
|
|
* The topmost check is done by exploiting this property. For each
|
|
* affected device node in the log list we check if this overlay is
|
|
* the one closest to the tail. If another overlay has affected this
|
|
* device node and is closest to the tail, then removal is not permited.
|
|
*/
|
|
static int overlay_removal_is_ok(struct overlay_changeset *remove_ovcs)
|
|
{
|
|
struct of_changeset_entry *remove_ce;
|
|
|
|
list_for_each_entry(remove_ce, &remove_ovcs->cset.entries, node) {
|
|
if (node_overlaps_later_cs(remove_ovcs, remove_ce->np)) {
|
|
pr_err("overlay #%d is not topmost\n", remove_ovcs->id);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* of_overlay_remove() - Revert and free an overlay changeset
|
|
* @ovcs_id: Pointer to overlay changeset id
|
|
*
|
|
* Removes an overlay if it is permissible. @ovcs_id was previously returned
|
|
* by of_overlay_apply().
|
|
*
|
|
* If an error occurred while attempting to revert the overlay changeset,
|
|
* then an attempt is made to re-apply any changeset entry that was
|
|
* reverted. If an error occurs on re-apply then the state of the device
|
|
* tree can not be determined, and any following attempt to apply or remove
|
|
* an overlay changeset will be refused.
|
|
*
|
|
* A non-zero return value will not revert the changeset if error is from:
|
|
* - parameter checks
|
|
* - overlay changeset pre-remove notifier
|
|
* - overlay changeset entry revert
|
|
*
|
|
* If an error is returned by an overlay changeset pre-remove notifier
|
|
* then no further overlay changeset pre-remove notifier will be called.
|
|
*
|
|
* If more than one notifier returns an error, then the last notifier
|
|
* error to occur is returned.
|
|
*
|
|
* A non-zero return value will revert the changeset if error is from:
|
|
* - overlay changeset entry notifier
|
|
* - overlay changeset post-remove notifier
|
|
*
|
|
* If an error is returned by an overlay changeset post-remove notifier
|
|
* then no further overlay changeset post-remove notifier will be called.
|
|
*
|
|
* Returns 0 on success, or a negative error number. *ovcs_id is set to
|
|
* zero after reverting the changeset, even if a subsequent error occurs.
|
|
*/
|
|
int of_overlay_remove(int *ovcs_id)
|
|
{
|
|
struct overlay_changeset *ovcs;
|
|
int ret, ret_apply, ret_tmp;
|
|
|
|
ret = 0;
|
|
|
|
if (devicetree_corrupt()) {
|
|
pr_err("suspect devicetree state, refuse to remove overlay\n");
|
|
ret = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
mutex_lock(&of_mutex);
|
|
|
|
ovcs = idr_find(&ovcs_idr, *ovcs_id);
|
|
if (!ovcs) {
|
|
ret = -ENODEV;
|
|
pr_err("remove: Could not find overlay #%d\n", *ovcs_id);
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (!overlay_removal_is_ok(ovcs)) {
|
|
ret = -EBUSY;
|
|
goto out_unlock;
|
|
}
|
|
|
|
ret = overlay_notify(ovcs, OF_OVERLAY_PRE_REMOVE);
|
|
if (ret) {
|
|
pr_err("overlay changeset pre-remove notify error %d\n", ret);
|
|
goto out_unlock;
|
|
}
|
|
|
|
list_del(&ovcs->ovcs_list);
|
|
|
|
ret_apply = 0;
|
|
ret = __of_changeset_revert_entries(&ovcs->cset, &ret_apply);
|
|
if (ret) {
|
|
if (ret_apply)
|
|
devicetree_state_flags |= DTSF_REVERT_FAIL;
|
|
goto out_unlock;
|
|
}
|
|
|
|
ret = __of_changeset_revert_notify(&ovcs->cset);
|
|
if (ret)
|
|
pr_err("overlay changeset entry notify error %d\n", ret);
|
|
/* notify failure is not fatal, continue */
|
|
|
|
*ovcs_id = 0;
|
|
|
|
ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_REMOVE);
|
|
if (ret_tmp) {
|
|
pr_err("overlay changeset post-remove notify error %d\n",
|
|
ret_tmp);
|
|
if (!ret)
|
|
ret = ret_tmp;
|
|
}
|
|
|
|
free_overlay_changeset(ovcs);
|
|
|
|
out_unlock:
|
|
mutex_unlock(&of_mutex);
|
|
|
|
out:
|
|
pr_debug("%s() err=%d\n", __func__, ret);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_overlay_remove);
|
|
|
|
/**
|
|
* of_overlay_remove_all() - Reverts and frees all overlay changesets
|
|
*
|
|
* Removes all overlays from the system in the correct order.
|
|
*
|
|
* Returns 0 on success, or a negative error number
|
|
*/
|
|
int of_overlay_remove_all(void)
|
|
{
|
|
struct overlay_changeset *ovcs, *ovcs_n;
|
|
int ret;
|
|
|
|
/* the tail of list is guaranteed to be safe to remove */
|
|
list_for_each_entry_safe_reverse(ovcs, ovcs_n, &ovcs_list, ovcs_list) {
|
|
ret = of_overlay_remove(&ovcs->id);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_overlay_remove_all);
|