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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_XBC_H
3#define _LINUX_XBC_H
4/*
5 * Extra Boot Config
6 * Copyright (C) 2019 Linaro Ltd.
7 * Author: Masami Hiramatsu <mhiramat@kernel.org>
8 */
9
10#include <linux/kernel.h>
11#include <linux/types.h>
12
13#define BOOTCONFIG_MAGIC "#BOOTCONFIG\n"
14#define BOOTCONFIG_MAGIC_LEN 12
15
16/* XBC tree node */
17struct xbc_node {
18 u16 next;
19 u16 child;
20 u16 parent;
21 u16 data;
22} __attribute__ ((__packed__));
23
24#define XBC_KEY 0
25#define XBC_VALUE (1 << 15)
26/* Maximum size of boot config is 32KB - 1 */
27#define XBC_DATA_MAX (XBC_VALUE - 1)
28
29#define XBC_NODE_MAX 1024
30#define XBC_KEYLEN_MAX 256
31#define XBC_DEPTH_MAX 16
32
33/* Node tree access raw APIs */
34struct xbc_node * __init xbc_root_node(void);
35int __init xbc_node_index(struct xbc_node *node);
36struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node);
37struct xbc_node * __init xbc_node_get_child(struct xbc_node *node);
38struct xbc_node * __init xbc_node_get_next(struct xbc_node *node);
39const char * __init xbc_node_get_data(struct xbc_node *node);
40
41/**
42 * xbc_node_is_value() - Test the node is a value node
43 * @node: An XBC node.
44 *
45 * Test the @node is a value node and return true if a value node, false if not.
46 */
47static inline __init bool xbc_node_is_value(struct xbc_node *node)
48{
49 return node->data & XBC_VALUE;
50}
51
52/**
53 * xbc_node_is_key() - Test the node is a key node
54 * @node: An XBC node.
55 *
56 * Test the @node is a key node and return true if a key node, false if not.
57 */
58static inline __init bool xbc_node_is_key(struct xbc_node *node)
59{
60 return !xbc_node_is_value(node);
61}
62
63/**
64 * xbc_node_is_array() - Test the node is an arraied value node
65 * @node: An XBC node.
66 *
67 * Test the @node is an arraied value node.
68 */
69static inline __init bool xbc_node_is_array(struct xbc_node *node)
70{
71 return xbc_node_is_value(node) && node->next != 0;
72}
73
74/**
75 * xbc_node_is_leaf() - Test the node is a leaf key node
76 * @node: An XBC node.
77 *
78 * Test the @node is a leaf key node which is a key node and has a value node
79 * or no child. Returns true if it is a leaf node, or false if not.
80 */
81static inline __init bool xbc_node_is_leaf(struct xbc_node *node)
82{
83 return xbc_node_is_key(node) &&
84 (!node->child || xbc_node_is_value(xbc_node_get_child(node)));
85}
86
87/* Tree-based key-value access APIs */
88struct xbc_node * __init xbc_node_find_child(struct xbc_node *parent,
89 const char *key);
90
91const char * __init xbc_node_find_value(struct xbc_node *parent,
92 const char *key,
93 struct xbc_node **vnode);
94
95struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
96 struct xbc_node *leaf);
97
98const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
99 struct xbc_node **leaf);
100
101/**
102 * xbc_find_value() - Find a value which matches the key
103 * @key: Search key
104 * @vnode: A container pointer of XBC value node.
105 *
106 * Search a value whose key matches @key from whole of XBC tree and return
107 * the value if found. Found value node is stored in *@vnode.
108 * Note that this can return 0-length string and store NULL in *@vnode for
109 * key-only (non-value) entry.
110 */
111static inline const char * __init
112xbc_find_value(const char *key, struct xbc_node **vnode)
113{
114 return xbc_node_find_value(NULL, key, vnode);
115}
116
117/**
118 * xbc_find_node() - Find a node which matches the key
119 * @key: Search key
120 *
121 * Search a (key) node whose key matches @key from whole of XBC tree and
122 * return the node if found. If not found, returns NULL.
123 */
124static inline struct xbc_node * __init xbc_find_node(const char *key)
125{
126 return xbc_node_find_child(NULL, key);
127}
128
129/**
130 * xbc_array_for_each_value() - Iterate value nodes on an array
131 * @anode: An XBC arraied value node
132 * @value: A value
133 *
134 * Iterate array value nodes and values starts from @anode. This is expected to
135 * be used with xbc_find_value() and xbc_node_find_value(), so that user can
136 * process each array entry node.
137 */
138#define xbc_array_for_each_value(anode, value) \
139 for (value = xbc_node_get_data(anode); anode != NULL ; \
140 anode = xbc_node_get_next(anode), \
141 value = anode ? xbc_node_get_data(anode) : NULL)
142
143/**
144 * xbc_node_for_each_child() - Iterate child nodes
145 * @parent: An XBC node.
146 * @child: Iterated XBC node.
147 *
148 * Iterate child nodes of @parent. Each child nodes are stored to @child.
149 */
150#define xbc_node_for_each_child(parent, child) \
151 for (child = xbc_node_get_child(parent); child != NULL ; \
152 child = xbc_node_get_next(child))
153
154/**
155 * xbc_node_for_each_array_value() - Iterate array entries of geven key
156 * @node: An XBC node.
157 * @key: A key string searched under @node
158 * @anode: Iterated XBC node of array entry.
159 * @value: Iterated value of array entry.
160 *
161 * Iterate array entries of given @key under @node. Each array entry node
162 * is stroed to @anode and @value. If the @node doesn't have @key node,
163 * it does nothing.
164 * Note that even if the found key node has only one value (not array)
165 * this executes block once. Hoever, if the found key node has no value
166 * (key-only node), this does nothing. So don't use this for testing the
167 * key-value pair existence.
168 */
169#define xbc_node_for_each_array_value(node, key, anode, value) \
170 for (value = xbc_node_find_value(node, key, &anode); value != NULL; \
171 anode = xbc_node_get_next(anode), \
172 value = anode ? xbc_node_get_data(anode) : NULL)
173
174/**
175 * xbc_node_for_each_key_value() - Iterate key-value pairs under a node
176 * @node: An XBC node.
177 * @knode: Iterated key node
178 * @value: Iterated value string
179 *
180 * Iterate key-value pairs under @node. Each key node and value string are
181 * stored in @knode and @value respectively.
182 */
183#define xbc_node_for_each_key_value(node, knode, value) \
184 for (knode = NULL, value = xbc_node_find_next_key_value(node, &knode);\
185 knode != NULL; value = xbc_node_find_next_key_value(node, &knode))
186
187/**
188 * xbc_for_each_key_value() - Iterate key-value pairs
189 * @knode: Iterated key node
190 * @value: Iterated value string
191 *
192 * Iterate key-value pairs in whole XBC tree. Each key node and value string
193 * are stored in @knode and @value respectively.
194 */
195#define xbc_for_each_key_value(knode, value) \
196 xbc_node_for_each_key_value(NULL, knode, value)
197
198/* Compose partial key */
199int __init xbc_node_compose_key_after(struct xbc_node *root,
200 struct xbc_node *node, char *buf, size_t size);
201
202/**
203 * xbc_node_compose_key() - Compose full key string of the XBC node
204 * @node: An XBC node.
205 * @buf: A buffer to store the key.
206 * @size: The size of the @buf.
207 *
208 * Compose the full-length key of the @node into @buf. Returns the total
209 * length of the key stored in @buf. Or returns -EINVAL if @node is NULL,
210 * and -ERANGE if the key depth is deeper than max depth.
211 */
212static inline int __init xbc_node_compose_key(struct xbc_node *node,
213 char *buf, size_t size)
214{
215 return xbc_node_compose_key_after(NULL, node, buf, size);
216}
217
218/* XBC node initializer */
219int __init xbc_init(char *buf);
220
221/* XBC cleanup data structures */
222void __init xbc_destroy_all(void);
223
224/* Debug dump functions */
225void __init xbc_debug_dump(void);
226
227#endif