blob: 78ca3674f09a85d5834bae0e2bb4d3a1427b07d3 [file] [log] [blame]
Joe Hershberger170ab112012-12-11 22:16:24 -06001/*
2 * (C) Copyright 2012
3 * Joe Hershberger, National Instruments, joe.hershberger@ni.com
4 *
5 * See file CREDITS for list of people who contributed to this
6 * project.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21 * MA 02111-1307 USA
22 */
23
24#include <common.h>
25#include <environment.h>
26
27#if defined(CONFIG_NEEDS_MANUAL_RELOC)
28DECLARE_GLOBAL_DATA_PTR;
29#endif
30
31/*
32 * Look up a callback function pointer by name
33 */
34struct env_clbk_tbl *find_env_callback(const char *name)
35{
36 struct env_clbk_tbl *clbkp;
37 int i;
38 int num_callbacks = ll_entry_count(struct env_clbk_tbl, env_clbk);
39
40 if (name == NULL)
41 return NULL;
42
43 /* look up the callback in the linker-list */
44 for (i = 0, clbkp = ll_entry_start(struct env_clbk_tbl, env_clbk);
45 i < num_callbacks;
46 i++, clbkp++) {
47 if (strcmp(name, clbkp->name) == 0)
48 return clbkp;
49 }
50
51 return NULL;
52}
53
54/*
55 * Look for a possible callback for a newly added variable
56 * This is called specifically when the variable did not exist in the hash
57 * previously, so the blanket update did not find this variable.
58 */
59void env_callback_init(ENTRY *var_entry)
60{
61 const char *var_name = var_entry->key;
62 const char *callback_list = getenv(ENV_CALLBACK_VAR);
63 char callback_name[256] = "";
64 struct env_clbk_tbl *clbkp;
65 int ret = 1;
66
67 /* look in the ".callbacks" var for a reference to this variable */
68 if (callback_list != NULL)
69 ret = env_attr_lookup(callback_list, var_name, callback_name);
70
71 /* only if not found there, look in the static list */
72 if (ret)
73 ret = env_attr_lookup(ENV_CALLBACK_LIST_STATIC, var_name,
74 callback_name);
75
76 /* if an association was found, set the callback pointer */
77 if (!ret && strlen(callback_name)) {
78 clbkp = find_env_callback(callback_name);
79 if (clbkp != NULL)
80#if defined(CONFIG_NEEDS_MANUAL_RELOC)
81 var_entry->callback = clbkp->callback + gd->reloc_off;
82#else
83 var_entry->callback = clbkp->callback;
84#endif
85 }
86}
87
88/*
89 * Called on each existing env var prior to the blanket update since removing
90 * a callback association should remove its callback.
91 */
92static int clear_callback(ENTRY *entry)
93{
94 entry->callback = NULL;
95
96 return 0;
97}
98
99/*
100 * Call for each element in the list that associates variables to callbacks
101 */
102static int set_callback(const char *name, const char *value)
103{
104 ENTRY e, *ep;
105 struct env_clbk_tbl *clbkp;
106
107 e.key = name;
108 e.data = NULL;
109 hsearch_r(e, FIND, &ep, &env_htab, 0);
110
111 /* does the env variable actually exist? */
112 if (ep != NULL) {
113 /* the assocaition delares no callback, so remove the pointer */
114 if (value == NULL || strlen(value) == 0)
115 ep->callback = NULL;
116 else {
117 /* assign the requested callback */
118 clbkp = find_env_callback(value);
119 if (clbkp != NULL)
120#if defined(CONFIG_NEEDS_MANUAL_RELOC)
121 ep->callback = clbkp->callback + gd->reloc_off;
122#else
123 ep->callback = clbkp->callback;
124#endif
125 }
126 }
127
128 return 0;
129}
130
131static int on_callbacks(const char *name, const char *value, enum env_op op,
132 int flags)
133{
134 /* remove all callbacks */
135 hwalk_r(&env_htab, clear_callback);
136
137 /* configure any static callback bindings */
138 env_attr_walk(ENV_CALLBACK_LIST_STATIC, set_callback);
139 /* configure any dynamic callback bindings */
140 env_attr_walk(value, set_callback);
141
142 return 0;
143}
144U_BOOT_ENV_CALLBACK(callbacks, on_callbacks);