1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * BCM947xx nvram variable access |
4 | * |
5 | * Copyright (C) 2005 Broadcom Corporation |
6 | * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org> |
7 | * Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de> |
8 | */ |
9 | |
10 | #include <linux/io.h> |
11 | #include <linux/types.h> |
12 | #include <linux/module.h> |
13 | #include <linux/kernel.h> |
14 | #include <linux/string.h> |
15 | #include <linux/mtd/mtd.h> |
16 | #include <linux/bcm47xx_nvram.h> |
17 | |
18 | #define NVRAM_MAGIC 0x48534C46 /* 'FLSH' */ |
19 | #define NVRAM_SPACE 0x10000 |
20 | #define NVRAM_MAX_GPIO_ENTRIES 32 |
21 | #define NVRAM_MAX_GPIO_VALUE_LEN 30 |
22 | |
23 | #define FLASH_MIN 0x00020000 /* Minimum flash size */ |
24 | |
25 | struct { |
26 | u32 ; |
27 | u32 ; |
28 | u32 ; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */ |
29 | u32 ; /* 0:15 sdram_config, 16:31 sdram_refresh */ |
30 | u32 ; /* ncdl values for memc */ |
31 | }; |
32 | |
33 | static char nvram_buf[NVRAM_SPACE]; |
34 | static size_t nvram_len; |
35 | static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000}; |
36 | |
37 | /** |
38 | * bcm47xx_nvram_is_valid - check for a valid NVRAM at specified memory |
39 | */ |
40 | static bool bcm47xx_nvram_is_valid(void __iomem *nvram) |
41 | { |
42 | return ((struct nvram_header *)nvram)->magic == NVRAM_MAGIC; |
43 | } |
44 | |
45 | /** |
46 | * bcm47xx_nvram_copy - copy NVRAM to internal buffer |
47 | */ |
48 | static void bcm47xx_nvram_copy(void __iomem *nvram_start, size_t res_size) |
49 | { |
50 | struct nvram_header __iomem * = nvram_start; |
51 | size_t copy_size; |
52 | |
53 | copy_size = header->len; |
54 | if (copy_size > res_size) { |
55 | pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n" ); |
56 | copy_size = res_size; |
57 | } |
58 | if (copy_size >= NVRAM_SPACE) { |
59 | pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n" , |
60 | copy_size, NVRAM_SPACE - 1); |
61 | copy_size = NVRAM_SPACE - 1; |
62 | } |
63 | |
64 | __ioread32_copy(to: nvram_buf, from: nvram_start, DIV_ROUND_UP(copy_size, 4)); |
65 | nvram_buf[NVRAM_SPACE - 1] = '\0'; |
66 | nvram_len = copy_size; |
67 | } |
68 | |
69 | /** |
70 | * bcm47xx_nvram_find_and_copy - find NVRAM on flash mapping & copy it |
71 | */ |
72 | static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_size) |
73 | { |
74 | size_t flash_size; |
75 | size_t offset; |
76 | int i; |
77 | |
78 | if (nvram_len) { |
79 | pr_warn("nvram already initialized\n" ); |
80 | return -EEXIST; |
81 | } |
82 | |
83 | /* TODO: when nvram is on nand flash check for bad blocks first. */ |
84 | |
85 | /* Try every possible flash size and check for NVRAM at its end */ |
86 | for (flash_size = FLASH_MIN; flash_size <= res_size; flash_size <<= 1) { |
87 | for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) { |
88 | offset = flash_size - nvram_sizes[i]; |
89 | if (bcm47xx_nvram_is_valid(nvram: flash_start + offset)) |
90 | goto found; |
91 | } |
92 | } |
93 | |
94 | /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */ |
95 | |
96 | offset = 4096; |
97 | if (bcm47xx_nvram_is_valid(nvram: flash_start + offset)) |
98 | goto found; |
99 | |
100 | offset = 1024; |
101 | if (bcm47xx_nvram_is_valid(nvram: flash_start + offset)) |
102 | goto found; |
103 | |
104 | pr_err("no nvram found\n" ); |
105 | return -ENXIO; |
106 | |
107 | found: |
108 | bcm47xx_nvram_copy(nvram_start: flash_start + offset, res_size: res_size - offset); |
109 | |
110 | return 0; |
111 | } |
112 | |
113 | int bcm47xx_nvram_init_from_iomem(void __iomem *nvram_start, size_t res_size) |
114 | { |
115 | if (nvram_len) { |
116 | pr_warn("nvram already initialized\n" ); |
117 | return -EEXIST; |
118 | } |
119 | |
120 | if (!bcm47xx_nvram_is_valid(nvram: nvram_start)) { |
121 | pr_err("No valid NVRAM found\n" ); |
122 | return -ENOENT; |
123 | } |
124 | |
125 | bcm47xx_nvram_copy(nvram_start, res_size); |
126 | |
127 | return 0; |
128 | } |
129 | EXPORT_SYMBOL_GPL(bcm47xx_nvram_init_from_iomem); |
130 | |
131 | /* |
132 | * On bcm47xx we need access to the NVRAM very early, so we can't use mtd |
133 | * subsystem to access flash. We can't even use platform device / driver to |
134 | * store memory offset. |
135 | * To handle this we provide following symbol. It's supposed to be called as |
136 | * soon as we get info about flash device, before any NVRAM entry is needed. |
137 | */ |
138 | int bcm47xx_nvram_init_from_mem(u32 base, u32 lim) |
139 | { |
140 | void __iomem *iobase; |
141 | int err; |
142 | |
143 | iobase = ioremap(offset: base, size: lim); |
144 | if (!iobase) |
145 | return -ENOMEM; |
146 | |
147 | err = bcm47xx_nvram_find_and_copy(flash_start: iobase, res_size: lim); |
148 | |
149 | iounmap(addr: iobase); |
150 | |
151 | return err; |
152 | } |
153 | |
154 | static int nvram_init(void) |
155 | { |
156 | #ifdef CONFIG_MTD |
157 | struct mtd_info *mtd; |
158 | struct nvram_header ; |
159 | size_t bytes_read; |
160 | int err; |
161 | |
162 | mtd = get_mtd_device_nm(name: "nvram" ); |
163 | if (IS_ERR(ptr: mtd)) |
164 | return -ENODEV; |
165 | |
166 | err = mtd_read(mtd, from: 0, len: sizeof(header), retlen: &bytes_read, buf: (uint8_t *)&header); |
167 | if (!err && header.magic == NVRAM_MAGIC && |
168 | header.len > sizeof(header)) { |
169 | nvram_len = header.len; |
170 | if (nvram_len >= NVRAM_SPACE) { |
171 | pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n" , |
172 | nvram_len, NVRAM_SPACE); |
173 | nvram_len = NVRAM_SPACE - 1; |
174 | } |
175 | |
176 | err = mtd_read(mtd, from: 0, len: nvram_len, retlen: &nvram_len, |
177 | buf: (u8 *)nvram_buf); |
178 | return err; |
179 | } |
180 | #endif |
181 | |
182 | return -ENXIO; |
183 | } |
184 | |
185 | int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len) |
186 | { |
187 | char *var, *value, *end, *eq; |
188 | int err; |
189 | |
190 | if (!name) |
191 | return -EINVAL; |
192 | |
193 | if (!nvram_len) { |
194 | err = nvram_init(); |
195 | if (err) |
196 | return err; |
197 | } |
198 | |
199 | /* Look for name=value and return value */ |
200 | var = &nvram_buf[sizeof(struct nvram_header)]; |
201 | end = nvram_buf + sizeof(nvram_buf); |
202 | while (var < end && *var) { |
203 | eq = strchr(var, '='); |
204 | if (!eq) |
205 | break; |
206 | value = eq + 1; |
207 | if (eq - var == strlen(name) && |
208 | strncmp(var, name, eq - var) == 0) |
209 | return snprintf(buf: val, size: val_len, fmt: "%s" , value); |
210 | var = value + strlen(value) + 1; |
211 | } |
212 | return -ENOENT; |
213 | } |
214 | EXPORT_SYMBOL(bcm47xx_nvram_getenv); |
215 | |
216 | int bcm47xx_nvram_gpio_pin(const char *name) |
217 | { |
218 | int i, err; |
219 | char nvram_var[] = "gpioXX" ; |
220 | char buf[NVRAM_MAX_GPIO_VALUE_LEN]; |
221 | |
222 | /* TODO: Optimize it to don't call getenv so many times */ |
223 | for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) { |
224 | err = snprintf(buf: nvram_var, size: sizeof(nvram_var), fmt: "gpio%i" , i); |
225 | if (err <= 0) |
226 | continue; |
227 | err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf)); |
228 | if (err <= 0) |
229 | continue; |
230 | if (!strcmp(name, buf)) |
231 | return i; |
232 | } |
233 | return -ENOENT; |
234 | } |
235 | EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin); |
236 | |
237 | char *bcm47xx_nvram_get_contents(size_t *nvram_size) |
238 | { |
239 | int err; |
240 | char *nvram; |
241 | |
242 | if (!nvram_len) { |
243 | err = nvram_init(); |
244 | if (err) |
245 | return NULL; |
246 | } |
247 | |
248 | *nvram_size = nvram_len - sizeof(struct nvram_header); |
249 | nvram = vmalloc(size: *nvram_size); |
250 | if (!nvram) |
251 | return NULL; |
252 | memcpy(nvram, &nvram_buf[sizeof(struct nvram_header)], *nvram_size); |
253 | |
254 | return nvram; |
255 | } |
256 | EXPORT_SYMBOL(bcm47xx_nvram_get_contents); |
257 | |
258 | |