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83d290c5 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
170ab110 JH |
2 | /* |
3 | * (C) Copyright 2012 | |
4 | * Joe Hershberger, National Instruments, joe.hershberger@ni.com | |
170ab110 JH |
5 | */ |
6 | ||
7 | #include <common.h> | |
7b51b576 | 8 | #include <env.h> |
f3998fdc | 9 | #include <env_internal.h> |
401d1c4f | 10 | #include <asm/global_data.h> |
170ab110 | 11 | |
170ab110 JH |
12 | /* |
13 | * Look up a callback function pointer by name | |
14 | */ | |
268d966d | 15 | static struct env_clbk_tbl *find_env_callback(const char *name) |
170ab110 JH |
16 | { |
17 | struct env_clbk_tbl *clbkp; | |
18 | int i; | |
19 | int num_callbacks = ll_entry_count(struct env_clbk_tbl, env_clbk); | |
20 | ||
21 | if (name == NULL) | |
22 | return NULL; | |
23 | ||
24 | /* look up the callback in the linker-list */ | |
25 | for (i = 0, clbkp = ll_entry_start(struct env_clbk_tbl, env_clbk); | |
26 | i < num_callbacks; | |
27 | i++, clbkp++) { | |
28 | if (strcmp(name, clbkp->name) == 0) | |
29 | return clbkp; | |
30 | } | |
31 | ||
32 | return NULL; | |
33 | } | |
34 | ||
1b610271 HS |
35 | static int first_call = 1; |
36 | static const char *callback_list; | |
37 | ||
170ab110 JH |
38 | /* |
39 | * Look for a possible callback for a newly added variable | |
40 | * This is called specifically when the variable did not exist in the hash | |
41 | * previously, so the blanket update did not find this variable. | |
42 | */ | |
dd2408ca | 43 | void env_callback_init(struct env_entry *var_entry) |
170ab110 JH |
44 | { |
45 | const char *var_name = var_entry->key; | |
170ab110 JH |
46 | char callback_name[256] = ""; |
47 | struct env_clbk_tbl *clbkp; | |
48 | int ret = 1; | |
49 | ||
1b610271 | 50 | if (first_call) { |
00caae6d | 51 | callback_list = env_get(ENV_CALLBACK_VAR); |
1b610271 HS |
52 | first_call = 0; |
53 | } | |
54 | ||
080019b8 RV |
55 | var_entry->callback = NULL; |
56 | ||
170ab110 JH |
57 | /* look in the ".callbacks" var for a reference to this variable */ |
58 | if (callback_list != NULL) | |
59 | ret = env_attr_lookup(callback_list, var_name, callback_name); | |
60 | ||
61 | /* only if not found there, look in the static list */ | |
62 | if (ret) | |
63 | ret = env_attr_lookup(ENV_CALLBACK_LIST_STATIC, var_name, | |
64 | callback_name); | |
65 | ||
66 | /* if an association was found, set the callback pointer */ | |
67 | if (!ret && strlen(callback_name)) { | |
68 | clbkp = find_env_callback(callback_name); | |
69 | if (clbkp != NULL) | |
170ab110 | 70 | var_entry->callback = clbkp->callback; |
170ab110 JH |
71 | } |
72 | } | |
73 | ||
74 | /* | |
75 | * Called on each existing env var prior to the blanket update since removing | |
76 | * a callback association should remove its callback. | |
77 | */ | |
dd2408ca | 78 | static int clear_callback(struct env_entry *entry) |
170ab110 JH |
79 | { |
80 | entry->callback = NULL; | |
81 | ||
82 | return 0; | |
83 | } | |
84 | ||
85 | /* | |
86 | * Call for each element in the list that associates variables to callbacks | |
87 | */ | |
cca98fd6 | 88 | static int set_callback(const char *name, const char *value, void *priv) |
170ab110 | 89 | { |
dd2408ca | 90 | struct env_entry e, *ep; |
170ab110 JH |
91 | struct env_clbk_tbl *clbkp; |
92 | ||
93 | e.key = name; | |
94 | e.data = NULL; | |
5a689439 | 95 | e.callback = NULL; |
3f0d6807 | 96 | hsearch_r(e, ENV_FIND, &ep, &env_htab, 0); |
170ab110 JH |
97 | |
98 | /* does the env variable actually exist? */ | |
99 | if (ep != NULL) { | |
100 | /* the assocaition delares no callback, so remove the pointer */ | |
101 | if (value == NULL || strlen(value) == 0) | |
102 | ep->callback = NULL; | |
103 | else { | |
104 | /* assign the requested callback */ | |
105 | clbkp = find_env_callback(value); | |
106 | if (clbkp != NULL) | |
170ab110 | 107 | ep->callback = clbkp->callback; |
170ab110 JH |
108 | } |
109 | } | |
110 | ||
111 | return 0; | |
112 | } | |
113 | ||
114 | static int on_callbacks(const char *name, const char *value, enum env_op op, | |
115 | int flags) | |
116 | { | |
117 | /* remove all callbacks */ | |
118 | hwalk_r(&env_htab, clear_callback); | |
119 | ||
120 | /* configure any static callback bindings */ | |
cca98fd6 | 121 | env_attr_walk(ENV_CALLBACK_LIST_STATIC, set_callback, NULL); |
170ab110 | 122 | /* configure any dynamic callback bindings */ |
cca98fd6 | 123 | env_attr_walk(value, set_callback, NULL); |
170ab110 JH |
124 | |
125 | return 0; | |
126 | } | |
127 | U_BOOT_ENV_CALLBACK(callbacks, on_callbacks); |