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Joe Hershberger170ab112012-12-11 22:16:24 -06001/*
2 * (C) Copyright 2012
3 * Joe Hershberger, National Instruments, joe.hershberger@ni.com
4 *
Wolfgang Denk1a459662013-07-08 09:37:19 +02005 * SPDX-License-Identifier: GPL-2.0+
Joe Hershberger170ab112012-12-11 22:16:24 -06006 */
7
8#include <common.h>
9#include <environment.h>
10
11#if defined(CONFIG_NEEDS_MANUAL_RELOC)
12DECLARE_GLOBAL_DATA_PTR;
13#endif
14
15/*
16 * Look up a callback function pointer by name
17 */
Tom Rini268d9662013-03-12 06:16:50 +000018static struct env_clbk_tbl *find_env_callback(const char *name)
Joe Hershberger170ab112012-12-11 22:16:24 -060019{
20 struct env_clbk_tbl *clbkp;
21 int i;
22 int num_callbacks = ll_entry_count(struct env_clbk_tbl, env_clbk);
23
24 if (name == NULL)
25 return NULL;
26
27 /* look up the callback in the linker-list */
28 for (i = 0, clbkp = ll_entry_start(struct env_clbk_tbl, env_clbk);
29 i < num_callbacks;
30 i++, clbkp++) {
31 if (strcmp(name, clbkp->name) == 0)
32 return clbkp;
33 }
34
35 return NULL;
36}
37
Heiko Schocher1b610272013-12-19 13:45:04 +010038static int first_call = 1;
39static const char *callback_list;
40
Joe Hershberger170ab112012-12-11 22:16:24 -060041/*
42 * Look for a possible callback for a newly added variable
43 * This is called specifically when the variable did not exist in the hash
44 * previously, so the blanket update did not find this variable.
45 */
46void env_callback_init(ENTRY *var_entry)
47{
48 const char *var_name = var_entry->key;
Joe Hershberger170ab112012-12-11 22:16:24 -060049 char callback_name[256] = "";
50 struct env_clbk_tbl *clbkp;
51 int ret = 1;
52
Heiko Schocher1b610272013-12-19 13:45:04 +010053 if (first_call) {
54 callback_list = getenv(ENV_CALLBACK_VAR);
55 first_call = 0;
56 }
57
Joe Hershberger170ab112012-12-11 22:16:24 -060058 /* look in the ".callbacks" var for a reference to this variable */
59 if (callback_list != NULL)
60 ret = env_attr_lookup(callback_list, var_name, callback_name);
61
62 /* only if not found there, look in the static list */
63 if (ret)
64 ret = env_attr_lookup(ENV_CALLBACK_LIST_STATIC, var_name,
65 callback_name);
66
67 /* if an association was found, set the callback pointer */
68 if (!ret && strlen(callback_name)) {
69 clbkp = find_env_callback(callback_name);
70 if (clbkp != NULL)
71#if defined(CONFIG_NEEDS_MANUAL_RELOC)
72 var_entry->callback = clbkp->callback + gd->reloc_off;
73#else
74 var_entry->callback = clbkp->callback;
75#endif
76 }
77}
78
79/*
80 * Called on each existing env var prior to the blanket update since removing
81 * a callback association should remove its callback.
82 */
83static int clear_callback(ENTRY *entry)
84{
85 entry->callback = NULL;
86
87 return 0;
88}
89
90/*
91 * Call for each element in the list that associates variables to callbacks
92 */
Joe Hershbergercca98fd2015-05-20 14:27:19 -050093static int set_callback(const char *name, const char *value, void *priv)
Joe Hershberger170ab112012-12-11 22:16:24 -060094{
95 ENTRY e, *ep;
96 struct env_clbk_tbl *clbkp;
97
98 e.key = name;
99 e.data = NULL;
100 hsearch_r(e, FIND, &ep, &env_htab, 0);
101
102 /* does the env variable actually exist? */
103 if (ep != NULL) {
104 /* the assocaition delares no callback, so remove the pointer */
105 if (value == NULL || strlen(value) == 0)
106 ep->callback = NULL;
107 else {
108 /* assign the requested callback */
109 clbkp = find_env_callback(value);
110 if (clbkp != NULL)
111#if defined(CONFIG_NEEDS_MANUAL_RELOC)
112 ep->callback = clbkp->callback + gd->reloc_off;
113#else
114 ep->callback = clbkp->callback;
115#endif
116 }
117 }
118
119 return 0;
120}
121
122static int on_callbacks(const char *name, const char *value, enum env_op op,
123 int flags)
124{
125 /* remove all callbacks */
126 hwalk_r(&env_htab, clear_callback);
127
128 /* configure any static callback bindings */
Joe Hershbergercca98fd2015-05-20 14:27:19 -0500129 env_attr_walk(ENV_CALLBACK_LIST_STATIC, set_callback, NULL);
Joe Hershberger170ab112012-12-11 22:16:24 -0600130 /* configure any dynamic callback bindings */
Joe Hershbergercca98fd2015-05-20 14:27:19 -0500131 env_attr_walk(value, set_callback, NULL);
Joe Hershberger170ab112012-12-11 22:16:24 -0600132
133 return 0;
134}
135U_BOOT_ENV_CALLBACK(callbacks, on_callbacks);