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Source at commit 9fe2a2d created 13 years 8 months ago. By hauke, brcm47xx: prepare brcm47xx patches for sending to mainline. | |
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1 | /* |
2 | * CFE environment variable access |
3 | * |
4 | * Copyright 2001-2003, Broadcom Corporation |
5 | * Copyright 2006, Felix Fietkau <nbd@openwrt.org> |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify it |
8 | * under the terms of the GNU General Public License as published by the |
9 | * Free Software Foundation; either version 2 of the License, or (at your |
10 | * option) any later version. |
11 | */ |
12 | |
13 | #include <linux/init.h> |
14 | #include <linux/module.h> |
15 | #include <linux/kernel.h> |
16 | #include <linux/string.h> |
17 | #include <asm/io.h> |
18 | #include <asm/uaccess.h> |
19 | |
20 | #define NVRAM_SIZE (0x1ff0) |
21 | static char _nvdata[NVRAM_SIZE]; |
22 | static char _valuestr[256]; |
23 | |
24 | /* |
25 | * TLV types. These codes are used in the "type-length-value" |
26 | * encoding of the items stored in the NVRAM device (flash or EEPROM) |
27 | * |
28 | * The layout of the flash/nvram is as follows: |
29 | * |
30 | * <type> <length> <data ...> <type> <length> <data ...> <type_end> |
31 | * |
32 | * The type code of "ENV_TLV_TYPE_END" marks the end of the list. |
33 | * The "length" field marks the length of the data section, not |
34 | * including the type and length fields. |
35 | * |
36 | * Environment variables are stored as follows: |
37 | * |
38 | * <type_env> <length> <flags> <name> = <value> |
39 | * |
40 | * If bit 0 (low bit) is set, the length is an 8-bit value. |
41 | * If bit 0 (low bit) is clear, the length is a 16-bit value |
42 | * |
43 | * Bit 7 set indicates "user" TLVs. In this case, bit 0 still |
44 | * indicates the size of the length field. |
45 | * |
46 | * Flags are from the constants below: |
47 | * |
48 | */ |
49 | #define ENV_LENGTH_16BITS 0x00 /* for low bit */ |
50 | #define ENV_LENGTH_8BITS 0x01 |
51 | |
52 | #define ENV_TYPE_USER 0x80 |
53 | |
54 | #define ENV_CODE_SYS(n,l) (((n)<<1)|(l)) |
55 | #define ENV_CODE_USER(n,l) ((((n)<<1)|(l)) | ENV_TYPE_USER) |
56 | |
57 | /* |
58 | * The actual TLV types we support |
59 | */ |
60 | |
61 | #define ENV_TLV_TYPE_END 0x00 |
62 | #define ENV_TLV_TYPE_ENV ENV_CODE_SYS(0,ENV_LENGTH_8BITS) |
63 | |
64 | /* |
65 | * Environment variable flags |
66 | */ |
67 | |
68 | #define ENV_FLG_NORMAL 0x00 /* normal read/write */ |
69 | #define ENV_FLG_BUILTIN 0x01 /* builtin - not stored in flash */ |
70 | #define ENV_FLG_READONLY 0x02 /* read-only - cannot be changed */ |
71 | |
72 | #define ENV_FLG_MASK 0xFF /* mask of attributes we keep */ |
73 | #define ENV_FLG_ADMIN 0x100 /* lets us internally override permissions */ |
74 | |
75 | |
76 | /* ********************************************************************* |
77 | * _nvram_read(buffer,offset,length) |
78 | * |
79 | * Read data from the NVRAM device |
80 | * |
81 | * Input parameters: |
82 | * buffer - destination buffer |
83 | * offset - offset of data to read |
84 | * length - number of bytes to read |
85 | * |
86 | * Return value: |
87 | * number of bytes read, or <0 if error occured |
88 | ********************************************************************* */ |
89 | static int |
90 | _nvram_read(unsigned char *nv_buf, unsigned char *buffer, int offset, int length) |
91 | { |
92 | int i; |
93 | if (offset > NVRAM_SIZE) |
94 | return -1; |
95 | |
96 | for ( i = 0; i < length; i++) { |
97 | buffer[i] = ((volatile unsigned char*)nv_buf)[offset + i]; |
98 | } |
99 | return length; |
100 | } |
101 | |
102 | |
103 | static char* |
104 | _strnchr(const char *dest,int c,size_t cnt) |
105 | { |
106 | while (*dest && (cnt > 0)) { |
107 | if (*dest == c) return (char *) dest; |
108 | dest++; |
109 | cnt--; |
110 | } |
111 | return NULL; |
112 | } |
113 | |
114 | |
115 | |
116 | /* |
117 | * Core support API: Externally visible. |
118 | */ |
119 | |
120 | /* |
121 | * Get the value of an NVRAM variable |
122 | * @param name name of variable to get |
123 | * @return value of variable or NULL if undefined |
124 | */ |
125 | |
126 | char* |
127 | cfe_env_get(unsigned char *nv_buf, char* name) |
128 | { |
129 | int size; |
130 | unsigned char *buffer; |
131 | unsigned char *ptr; |
132 | unsigned char *envval; |
133 | unsigned int reclen; |
134 | unsigned int rectype; |
135 | int offset; |
136 | int flg; |
137 | |
138 | if (!strcmp(name, "nvram_type")) |
139 | return "cfe"; |
140 | |
141 | size = NVRAM_SIZE; |
142 | buffer = &_nvdata[0]; |
143 | |
144 | ptr = buffer; |
145 | offset = 0; |
146 | |
147 | /* Read the record type and length */ |
148 | if (_nvram_read(nv_buf, ptr,offset,1) != 1) { |
149 | goto error; |
150 | } |
151 | |
152 | while ((*ptr != ENV_TLV_TYPE_END) && (size > 1)) { |
153 | |
154 | /* Adjust pointer for TLV type */ |
155 | rectype = *(ptr); |
156 | offset++; |
157 | size--; |
158 | |
159 | /* |
160 | * Read the length. It can be either 1 or 2 bytes |
161 | * depending on the code |
162 | */ |
163 | if (rectype & ENV_LENGTH_8BITS) { |
164 | /* Read the record type and length - 8 bits */ |
165 | if (_nvram_read(nv_buf, ptr,offset,1) != 1) { |
166 | goto error; |
167 | } |
168 | reclen = *(ptr); |
169 | size--; |
170 | offset++; |
171 | } |
172 | else { |
173 | /* Read the record type and length - 16 bits, MSB first */ |
174 | if (_nvram_read(nv_buf, ptr,offset,2) != 2) { |
175 | goto error; |
176 | } |
177 | reclen = (((unsigned int) *(ptr)) << 8) + (unsigned int) *(ptr+1); |
178 | size -= 2; |
179 | offset += 2; |
180 | } |
181 | |
182 | if (reclen > size) |
183 | break; /* should not happen, bad NVRAM */ |
184 | |
185 | switch (rectype) { |
186 | case ENV_TLV_TYPE_ENV: |
187 | /* Read the TLV data */ |
188 | if (_nvram_read(nv_buf, ptr,offset,reclen) != reclen) |
189 | goto error; |
190 | flg = *ptr++; |
191 | envval = (unsigned char *) _strnchr(ptr,'=',(reclen-1)); |
192 | if (envval) { |
193 | *envval++ = '\0'; |
194 | memcpy(_valuestr,envval,(reclen-1)-(envval-ptr)); |
195 | _valuestr[(reclen-1)-(envval-ptr)] = '\0'; |
196 | #if 0 |
197 | printk(KERN_INFO "NVRAM:%s=%s\n", ptr, _valuestr); |
198 | #endif |
199 | if(!strcmp(ptr, name)){ |
200 | return _valuestr; |
201 | } |
202 | if((strlen(ptr) > 1) && !strcmp(&ptr[1], name)) |
203 | return _valuestr; |
204 | } |
205 | break; |
206 | |
207 | default: |
208 | /* Unknown TLV type, skip it. */ |
209 | break; |
210 | } |
211 | |
212 | /* |
213 | * Advance to next TLV |
214 | */ |
215 | |
216 | size -= (int)reclen; |
217 | offset += reclen; |
218 | |
219 | /* Read the next record type */ |
220 | ptr = buffer; |
221 | if (_nvram_read(nv_buf, ptr,offset,1) != 1) |
222 | goto error; |
223 | } |
224 | |
225 | error: |
226 | return NULL; |
227 | |
228 | } |
229 | |
230 |