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 <[email protected]> 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 */ 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 */ 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 */ 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 */ 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 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 */ 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 */ 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