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 #define BOOTCONFIG_ALIGN_SHIFT 2
16 #define BOOTCONFIG_ALIGN (1 << BOOTCONFIG_ALIGN_SHIFT)
17 #define BOOTCONFIG_ALIGN_MASK (BOOTCONFIG_ALIGN - 1)
18
19 /* XBC tree node */
20 struct xbc_node {
21 u16 next;
22 u16 child;
23 u16 parent;
24 u16 data;
25 } __attribute__ ((__packed__));
26
27 #define XBC_KEY 0
28 #define XBC_VALUE (1 << 15)
29 /* Maximum size of boot config is 32KB - 1 */
30 #define XBC_DATA_MAX (XBC_VALUE - 1)
31
32 #define XBC_NODE_MAX 1024
33 #define XBC_KEYLEN_MAX 256
34 #define XBC_DEPTH_MAX 16
35
36 /* Node tree access raw APIs */
37 struct xbc_node * __init xbc_root_node(void);
38 int __init xbc_node_index(struct xbc_node *node);
39 struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node);
40 struct xbc_node * __init xbc_node_get_child(struct xbc_node *node);
41 struct xbc_node * __init xbc_node_get_next(struct xbc_node *node);
42 const char * __init xbc_node_get_data(struct xbc_node *node);
43
44 /**
45 * xbc_node_is_value() - Test the node is a value node
46 * @node: An XBC node.
47 *
48 * Test the @node is a value node and return true if a value node, false if not.
49 */
xbc_node_is_value(struct xbc_node * node)50 static inline __init bool xbc_node_is_value(struct xbc_node *node)
51 {
52 return node->data & XBC_VALUE;
53 }
54
55 /**
56 * xbc_node_is_key() - Test the node is a key node
57 * @node: An XBC node.
58 *
59 * Test the @node is a key node and return true if a key node, false if not.
60 */
xbc_node_is_key(struct xbc_node * node)61 static inline __init bool xbc_node_is_key(struct xbc_node *node)
62 {
63 return !xbc_node_is_value(node);
64 }
65
66 /**
67 * xbc_node_is_array() - Test the node is an arraied value node
68 * @node: An XBC node.
69 *
70 * Test the @node is an arraied value node.
71 */
xbc_node_is_array(struct xbc_node * node)72 static inline __init bool xbc_node_is_array(struct xbc_node *node)
73 {
74 return xbc_node_is_value(node) && node->next != 0;
75 }
76
77 /**
78 * xbc_node_is_leaf() - Test the node is a leaf key node
79 * @node: An XBC node.
80 *
81 * Test the @node is a leaf key node which is a key node and has a value node
82 * or no child. Returns true if it is a leaf node, or false if not.
83 */
xbc_node_is_leaf(struct xbc_node * node)84 static inline __init bool xbc_node_is_leaf(struct xbc_node *node)
85 {
86 return xbc_node_is_key(node) &&
87 (!node->child || xbc_node_is_value(xbc_node_get_child(node)));
88 }
89
90 /* Tree-based key-value access APIs */
91 struct xbc_node * __init xbc_node_find_child(struct xbc_node *parent,
92 const char *key);
93
94 const char * __init xbc_node_find_value(struct xbc_node *parent,
95 const char *key,
96 struct xbc_node **vnode);
97
98 struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
99 struct xbc_node *leaf);
100
101 const char * __init xbc_node_find_next_key_value(struct xbc_node *root,
102 struct xbc_node **leaf);
103
104 /**
105 * xbc_find_value() - Find a value which matches the key
106 * @key: Search key
107 * @vnode: A container pointer of XBC value node.
108 *
109 * Search a value whose key matches @key from whole of XBC tree and return
110 * the value if found. Found value node is stored in *@vnode.
111 * Note that this can return 0-length string and store NULL in *@vnode for
112 * key-only (non-value) entry.
113 */
114 static inline const char * __init
xbc_find_value(const char * key,struct xbc_node ** vnode)115 xbc_find_value(const char *key, struct xbc_node **vnode)
116 {
117 return xbc_node_find_value(NULL, key, vnode);
118 }
119
120 /**
121 * xbc_find_node() - Find a node which matches the key
122 * @key: Search key
123 *
124 * Search a (key) node whose key matches @key from whole of XBC tree and
125 * return the node if found. If not found, returns NULL.
126 */
xbc_find_node(const char * key)127 static inline struct xbc_node * __init xbc_find_node(const char *key)
128 {
129 return xbc_node_find_child(NULL, key);
130 }
131
132 /**
133 * xbc_array_for_each_value() - Iterate value nodes on an array
134 * @anode: An XBC arraied value node
135 * @value: A value
136 *
137 * Iterate array value nodes and values starts from @anode. This is expected to
138 * be used with xbc_find_value() and xbc_node_find_value(), so that user can
139 * process each array entry node.
140 */
141 #define xbc_array_for_each_value(anode, value) \
142 for (value = xbc_node_get_data(anode); anode != NULL ; \
143 anode = xbc_node_get_next(anode), \
144 value = anode ? xbc_node_get_data(anode) : NULL)
145
146 /**
147 * xbc_node_for_each_child() - Iterate child nodes
148 * @parent: An XBC node.
149 * @child: Iterated XBC node.
150 *
151 * Iterate child nodes of @parent. Each child nodes are stored to @child.
152 */
153 #define xbc_node_for_each_child(parent, child) \
154 for (child = xbc_node_get_child(parent); child != NULL ; \
155 child = xbc_node_get_next(child))
156
157 /**
158 * xbc_node_for_each_array_value() - Iterate array entries of geven key
159 * @node: An XBC node.
160 * @key: A key string searched under @node
161 * @anode: Iterated XBC node of array entry.
162 * @value: Iterated value of array entry.
163 *
164 * Iterate array entries of given @key under @node. Each array entry node
165 * is stroed to @anode and @value. If the @node doesn't have @key node,
166 * it does nothing.
167 * Note that even if the found key node has only one value (not array)
168 * this executes block once. Hoever, if the found key node has no value
169 * (key-only node), this does nothing. So don't use this for testing the
170 * key-value pair existence.
171 */
172 #define xbc_node_for_each_array_value(node, key, anode, value) \
173 for (value = xbc_node_find_value(node, key, &anode); value != NULL; \
174 anode = xbc_node_get_next(anode), \
175 value = anode ? xbc_node_get_data(anode) : NULL)
176
177 /**
178 * xbc_node_for_each_key_value() - Iterate key-value pairs under a node
179 * @node: An XBC node.
180 * @knode: Iterated key node
181 * @value: Iterated value string
182 *
183 * Iterate key-value pairs under @node. Each key node and value string are
184 * stored in @knode and @value respectively.
185 */
186 #define xbc_node_for_each_key_value(node, knode, value) \
187 for (knode = NULL, value = xbc_node_find_next_key_value(node, &knode);\
188 knode != NULL; value = xbc_node_find_next_key_value(node, &knode))
189
190 /**
191 * xbc_for_each_key_value() - Iterate key-value pairs
192 * @knode: Iterated key node
193 * @value: Iterated value string
194 *
195 * Iterate key-value pairs in whole XBC tree. Each key node and value string
196 * are stored in @knode and @value respectively.
197 */
198 #define xbc_for_each_key_value(knode, value) \
199 xbc_node_for_each_key_value(NULL, knode, value)
200
201 /* Compose partial key */
202 int __init xbc_node_compose_key_after(struct xbc_node *root,
203 struct xbc_node *node, char *buf, size_t size);
204
205 /**
206 * xbc_node_compose_key() - Compose full key string of the XBC node
207 * @node: An XBC node.
208 * @buf: A buffer to store the key.
209 * @size: The size of the @buf.
210 *
211 * Compose the full-length key of the @node into @buf. Returns the total
212 * length of the key stored in @buf. Or returns -EINVAL if @node is NULL,
213 * and -ERANGE if the key depth is deeper than max depth.
214 */
xbc_node_compose_key(struct xbc_node * node,char * buf,size_t size)215 static inline int __init xbc_node_compose_key(struct xbc_node *node,
216 char *buf, size_t size)
217 {
218 return xbc_node_compose_key_after(NULL, node, buf, size);
219 }
220
221 /* XBC node initializer */
222 int __init xbc_init(char *buf, const char **emsg, int *epos);
223
224
225 /* XBC cleanup data structures */
226 void __init xbc_destroy_all(void);
227
228 /* Debug dump functions */
229 void __init xbc_debug_dump(void);
230
231 #endif
232