1/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 * Common environment functions and definitions
4 *
5 * (C) Copyright 2000-2009
6 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
7 */
8
9#ifndef __ENV_H
10#define __ENV_H
11
12#include <compiler.h>
13#include <stdbool.h>
14#include <linux/types.h>
15
16struct environment_s;
17
18/* Value for environment validity */
19enum env_valid {
20	ENV_INVALID,	/* No valid environment */
21	ENV_VALID,	/* First or only environment is valid */
22	ENV_REDUND,	/* Redundant environment is valid */
23};
24
25/** enum env_op - environment callback operation */
26enum env_op {
27	env_op_create,
28	env_op_delete,
29	env_op_overwrite,
30};
31
32/** struct env_clbk_tbl - declares a new callback */
33struct env_clbk_tbl {
34	const char *name;		/* Callback name */
35	int (*callback)(const char *name, const char *value, enum env_op op,
36			int flags);
37};
38
39/*
40 * Define a callback that can be associated with variables.
41 * when associated through the ".callbacks" environment variable, the callback
42 * will be executed any time the variable is inserted, overwritten, or deleted.
43 *
44 * For SPL these are silently dropped to reduce code size, since environment
45 * callbacks are not supported with SPL.
46 */
47#ifdef CONFIG_SPL_BUILD
48#define U_BOOT_ENV_CALLBACK(name, callback) \
49	static inline __maybe_unused void _u_boot_env_noop_##name(void) \
50	{ \
51		(void)callback; \
52	}
53#else
54#define U_BOOT_ENV_CALLBACK(name, callback) \
55	ll_entry_declare(struct env_clbk_tbl, name, env_clbk) = \
56	{#name, callback}
57#endif
58
59/** enum env_redund_flags - Flags for the redundand_environment */
60enum env_redund_flags {
61	ENV_REDUND_OBSOLETE = 0,
62	ENV_REDUND_ACTIVE = 1,
63};
64
65/**
66 * env_get_id() - Gets a sequence number for the environment
67 *
68 * This value increments every time the environment changes, so can be used an
69 * an indication of this
70 *
71 * Return: environment ID
72 */
73int env_get_id(void);
74
75/**
76 * env_inc_id() - Increase the sequence number for the environment
77 *
78 * Increment the value that is used by env_get_id() to inform callers
79 * if the environment has changed since they last checked.
80 */
81void env_inc_id(void);
82
83/**
84 * env_init() - Set up the pre-relocation environment
85 *
86 * This locates the environment or uses the default if nothing is available.
87 * This must be called before env_get() will work.
88 *
89 * Return: 0 if OK, -ENODEV if no environment drivers are enabled
90 */
91int env_init(void);
92
93/**
94 * env_relocate() - Set up the post-relocation environment
95 *
96 * This loads the environment into RAM so that it can be modified. This is
97 * called after relocation, before the environment is used
98 */
99void env_relocate(void);
100
101/**
102 * env_get() - Look up the value of an environment variable
103 *
104 * In U-Boot proper this can be called before relocation (which is when the
105 * environment is loaded from storage, i.e. GD_FLG_ENV_READY is 0). In that
106 * case this function calls env_get_f().
107 *
108 * @varname:	Variable to look up
109 * Return: value of variable, or NULL if not found
110 */
111char *env_get(const char *varname);
112
113/*
114 * Like env_get, but prints an error if envvar isn't defined in the
115 * environment.  It always returns what env_get does, so it can be used in
116 * place of env_get without changing error handling otherwise.
117 *
118 * @varname:	Variable to look up
119 * Return: value of variable, or NULL if not found
120 */
121char *from_env(const char *envvar);
122
123/**
124 * env_get_f() - Look up the value of an environment variable (early)
125 *
126 * This function is called from env_get() if the environment has not been
127 * loaded yet (GD_FLG_ENV_READY flag is 0). Some environment locations will
128 * support reading the value (slowly) and some will not.
129 *
130 * @varname:	Variable to look up
131 * Return: actual length of the variable value excluding the terminating
132 *	NULL-byte, or -1 if the variable is not found
133 */
134int env_get_f(const char *name, char *buf, unsigned int len);
135
136/**
137 * env_get_yesno() - Read an environment variable as a boolean
138 *
139 * Return: 1 if yes/true (Y/y/T/t), -1 if variable does not exist (i.e. default
140 *	to true), 0 if otherwise
141 */
142int env_get_yesno(const char *var);
143
144/**
145 * env_get_autostart() - Check if autostart is enabled
146 *
147 * Return: true if the "autostart" env var exists and is set to "yes"
148 */
149bool env_get_autostart(void);
150
151/**
152 * env_set() - set an environment variable
153 *
154 * This sets or deletes the value of an environment variable. For setting the
155 * value the variable is created if it does not already exist.
156 *
157 * @varname: Variable to adjust
158 * @value: Value to set for the variable, or NULL or "" to delete the variable
159 * Return: 0 if OK, 1 on error
160 */
161int env_set(const char *varname, const char *value);
162
163/**
164 * env_get_ulong() - Return an environment variable as an integer value
165 *
166 * Most U-Boot environment variables store hex values. For those which store
167 * (e.g.) base-10 integers, this function can be used to read the value.
168 *
169 * @name:	Variable to look up
170 * @base:	Base to use (e.g. 10 for base 10, 2 for binary)
171 * @default_val: Default value to return if no value is found
172 * Return: the value found, or @default_val if none
173 */
174ulong env_get_ulong(const char *name, int base, ulong default_val);
175
176/**
177 * env_set_ulong() - set an environment variable to an integer
178 *
179 * @varname: Variable to adjust
180 * @value: Value to set for the variable (will be converted to a string)
181 * Return: 0 if OK, 1 on error
182 */
183int env_set_ulong(const char *varname, ulong value);
184
185/**
186 * env_get_hex() - Return an environment variable as a hex value
187 *
188 * Decode an environment as a hex number (it may or may not have a 0x
189 * prefix). If the environment variable cannot be found, or does not start
190 * with hex digits, the default value is returned.
191 *
192 * @varname:		Variable to decode
193 * @default_val:	Value to return on error
194 */
195ulong env_get_hex(const char *varname, ulong default_val);
196
197/**
198 * env_set_hex() - set an environment variable to a hex value
199 *
200 * @varname: Variable to adjust
201 * @value: Value to set for the variable (will be converted to a hex string)
202 * Return: 0 if OK, 1 on error
203 */
204int env_set_hex(const char *varname, ulong value);
205
206/**
207 * env_set_addr - Set an environment variable to an address in hex
208 *
209 * @varname:	Environment variable to set
210 * @addr:	Value to set it to
211 * Return: 0 if ok, 1 on error
212 */
213static inline int env_set_addr(const char *varname, const void *addr)
214{
215	return env_set_hex(varname, (ulong)addr);
216}
217
218/**
219 * env_complete() - return an auto-complete for environment variables
220 *
221 * @var: partial name to auto-complete
222 * @maxv: Maximum number of matches to return
223 * @cmdv: Returns a list of possible matches
224 * @maxsz: Size of buffer to use for matches
225 * @buf: Buffer to use for matches
226 * @dollar_comp: non-zero to wrap each match in ${...}
227 * Return: number of matches found (in @cmdv)
228 */
229int env_complete(char *var, int maxv, char *cmdv[], int maxsz, char *buf,
230		 bool dollar_comp);
231
232/**
233 * eth_env_get_enetaddr() - Get an ethernet address from the environmnet
234 *
235 * @name: Environment variable to get (e.g. "ethaddr")
236 * @enetaddr: Place to put MAC address (6 bytes)
237 * Return: 1 if OK, 0 on error
238 */
239int eth_env_get_enetaddr(const char *name, uint8_t *enetaddr);
240
241/**
242 * eth_env_set_enetaddr() - Set an ethernet address in the environmnet
243 *
244 * @name: Environment variable to set (e.g. "ethaddr")
245 * @enetaddr: Pointer to MAC address to put into the variable (6 bytes)
246 * Return: 0 if OK, non-zero otherwise
247 */
248int eth_env_set_enetaddr(const char *name, const uint8_t *enetaddr);
249
250/**
251 * env_set_default_vars() - reset variables to their default value
252 *
253 * This resets individual variables to their value in the default environment
254 *
255 * @nvars: Number of variables to set/reset
256 * @vars: List of variables to set/reset
257 * @flags: Flags controlling matching (H_... - see search.h)
258 */
259int env_set_default_vars(int nvars, char *const vars[], int flags);
260
261/**
262 * env_load() - Load the environment from storage
263 *
264 * Return: 0 if OK, -ve on error
265 */
266int env_load(void);
267
268/**
269 * env_reload() - Re-Load the environment from current storage
270 *
271 * Return: 0 if OK, -ve on error
272 */
273int env_reload(void);
274
275/**
276 * env_save() - Save the environment to storage
277 *
278 * Return: 0 if OK, -ve on error
279 */
280int env_save(void);
281
282/**
283 * env_erase() - Erase the environment on storage
284 *
285 * Return: 0 if OK, -ve on error
286 */
287int env_erase(void);
288
289/**
290 * env_select() - Select the environment storage
291 *
292 * Return: 0 if OK, -ve on error
293 */
294int env_select(const char *name);
295
296/**
297 * env_import() - Import from a binary representation into hash table
298 *
299 * This imports the environment from a buffer. The format for each variable is
300 * var=value\0 with a double \0 at the end of the buffer.
301 *
302 * @buf: Buffer containing the environment (struct environemnt_s *)
303 * @check: non-zero to check the CRC at the start of the environment, 0 to
304 *	ignore it
305 * @flags: Flags controlling matching (H_... - see search.h)
306 * Return: 0 if imported successfully, -ENOMSG if the CRC was bad, -EIO if
307 *	something else went wrong
308 */
309int env_import(const char *buf, int check, int flags);
310
311/**
312 * env_export() - Export the environment to a buffer
313 *
314 * Export from hash table into binary representation
315 *
316 * @env_out: Buffer to contain the environment (must be large enough!)
317 * Return: 0 if OK, 1 on error
318 */
319int env_export(struct environment_s *env_out);
320
321/**
322 * env_check_redund() - check the two redundant environments
323 *   and find out, which is the valid one.
324 *
325 * @buf1: First environment (struct environemnt_s *)
326 * @buf1_read_fail: 0 if buf1 is valid, non-zero if invalid
327 * @buf2: Second environment (struct environemnt_s *)
328 * @buf2_read_fail: 0 if buf2 is valid, non-zero if invalid
329 * Return: 0 if OK,
330 *	-EIO if no environment is valid,
331 *	-ENOMSG if the CRC was bad
332 */
333
334int env_check_redund(const char *buf1, int buf1_read_fail,
335		     const char *buf2, int buf2_read_fail);
336
337/**
338 * env_import_redund() - Select and import one of two redundant environments
339 *
340 * @buf1: First environment (struct environemnt_s *)
341 * @buf1_read_fail: 0 if buf1 is valid, non-zero if invalid
342 * @buf2: Second environment (struct environemnt_s *)
343 * @buf2_read_fail: 0 if buf2 is valid, non-zero if invalid
344 * @flags: Flags controlling matching (H_... - see search.h)
345 * Return: 0 if OK, -EIO if no environment is valid, -ENOMSG if the CRC was bad
346 */
347int env_import_redund(const char *buf1, int buf1_read_fail,
348		      const char *buf2, int buf2_read_fail,
349		      int flags);
350
351/**
352 * env_get_default() - Look up a variable from the default environment
353 *
354 * @name: Variable to look up
355 * Return: value if found, NULL if not found in default environment
356 */
357char *env_get_default(const char *name);
358
359/**
360 * env_get_default_into() - Look up a variable from the default environment and
361 * copy its value in buf.
362 *
363 * @name: Variable to look up
364 * Return: actual length of the variable value excluding the terminating
365 *	NULL-byte, or -1 if the variable is not found
366 */
367int env_get_default_into(const char *name, char *buf, unsigned int len);
368
369/* [re]set to the default environment */
370void env_set_default(const char *s, int flags);
371
372/**
373 * env_import_fdt() - Import environment values from device tree blob
374 *
375 * This uses the value of the environment variable "env_fdt_path" as a
376 * path to an fdt node, whose property/value pairs are added to the
377 * environment.
378 */
379#ifdef CONFIG_ENV_IMPORT_FDT
380void env_import_fdt(void);
381#else
382static inline void env_import_fdt(void) {}
383#endif
384
385#endif
386