include/linux/bootconfig.h

   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 */
  17 struct 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 */
  34 struct xbc_node * __init xbc_root_node(void);
  35 int __init xbc_node_index(struct xbc_node *node);
  36 struct xbc_node * __init xbc_node_get_parent(struct xbc_node *node);
  37 struct xbc_node * __init xbc_node_get_child(struct xbc_node *node);
  38 struct xbc_node * __init xbc_node_get_next(struct xbc_node *node);
  39 const 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  */
  47 static 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  */
  58 static 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  */
  69 static 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  */
  81 static 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 */
  88 struct xbc_node * __init xbc_node_find_child(struct xbc_node *parent,
  89                                              const char *key);
  90
  91 const char * __init xbc_node_find_value(struct xbc_node *parent,
  92                                         const char *key,
  93                                         struct xbc_node **vnode);
  94
  95 struct xbc_node * __init xbc_node_find_next_leaf(struct xbc_node *root,
  96                                                  struct xbc_node *leaf);
  97
  98 const 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  */
 111 static inline const char * __init
 112 xbc_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  */
 124 static 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 */
 199 int __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  */
 212 static 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 */
 219 int __init xbc_init(char *buf);
 220
 221 /* XBC cleanup data structures */
 222 void __init xbc_destroy_all(void);
 223
 224 /* Debug dump functions */
 225 void __init xbc_debug_dump(void);
 226
 227 #endif