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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
25struct nvram_header {
26 u32 magic;
27 u32 len;
28 u32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
29 u32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */
30 u32 config_ncdl; /* ncdl values for memc */
31};
32
33static char nvram_buf[NVRAM_SPACE];
34static size_t nvram_len;
35static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000};
36
37/**
38 * bcm47xx_nvram_is_valid - check for a valid NVRAM at specified memory
39 */
40static 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 */
48static void bcm47xx_nvram_copy(void __iomem *nvram_start, size_t res_size)
49{
50 struct nvram_header __iomem *header = 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(nvram_buf, 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 */
72static 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(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(flash_start + offset))
98 goto found;
99
100 offset = 1024;
101 if (bcm47xx_nvram_is_valid(flash_start + offset))
102 goto found;
103
104 pr_err("no nvram found\n");
105 return -ENXIO;
106
107found:
108 bcm47xx_nvram_copy(flash_start + offset, res_size - offset);
109
110 return 0;
111}
112
113int 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_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}
129EXPORT_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 */
138int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
139{
140 void __iomem *iobase;
141 int err;
142
143 iobase = ioremap(base, lim);
144 if (!iobase)
145 return -ENOMEM;
146
147 err = bcm47xx_nvram_find_and_copy(iobase, lim);
148
149 iounmap(iobase);
150
151 return err;
152}
153
154static int nvram_init(void)
155{
156#ifdef CONFIG_MTD
157 struct mtd_info *mtd;
158 struct nvram_header header;
159 size_t bytes_read;
160 int err;
161
162 mtd = get_mtd_device_nm("nvram");
163 if (IS_ERR(mtd))
164 return -ENODEV;
165
166 err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (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, 0, nvram_len, &nvram_len,
177 (u8 *)nvram_buf);
178 return err;
179 }
180#endif
181
182 return -ENXIO;
183}
184
185int 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(val, val_len, "%s", value);
210 var = value + strlen(value) + 1;
211 }
212 return -ENOENT;
213}
214EXPORT_SYMBOL(bcm47xx_nvram_getenv);
215
216int 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(nvram_var, sizeof(nvram_var), "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}
235EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
236
237char *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(*nvram_size);
250 if (!nvram)
251 return NULL;
252 memcpy(nvram, &nvram_buf[sizeof(struct nvram_header)], *nvram_size);
253
254 return nvram;
255}
256EXPORT_SYMBOL(bcm47xx_nvram_get_contents);
257
1/*
2 * BCM947xx nvram variable access
3 *
4 * Copyright (C) 2005 Broadcom Corporation
5 * Copyright (C) 2006 Felix Fietkau <nbd@openwrt.org>
6 * Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version.
12 */
13
14#include <linux/io.h>
15#include <linux/types.h>
16#include <linux/module.h>
17#include <linux/kernel.h>
18#include <linux/string.h>
19#include <linux/mtd/mtd.h>
20#include <linux/bcm47xx_nvram.h>
21
22#define NVRAM_MAGIC 0x48534C46 /* 'FLSH' */
23#define NVRAM_SPACE 0x10000
24#define NVRAM_MAX_GPIO_ENTRIES 32
25#define NVRAM_MAX_GPIO_VALUE_LEN 30
26
27#define FLASH_MIN 0x00020000 /* Minimum flash size */
28
29struct nvram_header {
30 u32 magic;
31 u32 len;
32 u32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
33 u32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */
34 u32 config_ncdl; /* ncdl values for memc */
35};
36
37static char nvram_buf[NVRAM_SPACE];
38static size_t nvram_len;
39static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
40
41static u32 find_nvram_size(void __iomem *end)
42{
43 struct nvram_header __iomem *header;
44 int i;
45
46 for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
47 header = (struct nvram_header *)(end - nvram_sizes[i]);
48 if (header->magic == NVRAM_MAGIC)
49 return nvram_sizes[i];
50 }
51
52 return 0;
53}
54
55/* Probe for NVRAM header */
56static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
57{
58 struct nvram_header __iomem *header;
59 u32 off;
60 u32 size;
61
62 if (nvram_len) {
63 pr_warn("nvram already initialized\n");
64 return -EEXIST;
65 }
66
67 /* TODO: when nvram is on nand flash check for bad blocks first. */
68 off = FLASH_MIN;
69 while (off <= lim) {
70 /* Windowed flash access */
71 size = find_nvram_size(iobase + off);
72 if (size) {
73 header = (struct nvram_header *)(iobase + off - size);
74 goto found;
75 }
76 off <<= 1;
77 }
78
79 /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
80 header = (struct nvram_header *)(iobase + 4096);
81 if (header->magic == NVRAM_MAGIC) {
82 size = NVRAM_SPACE;
83 goto found;
84 }
85
86 header = (struct nvram_header *)(iobase + 1024);
87 if (header->magic == NVRAM_MAGIC) {
88 size = NVRAM_SPACE;
89 goto found;
90 }
91
92 pr_err("no nvram found\n");
93 return -ENXIO;
94
95found:
96 __ioread32_copy(nvram_buf, header, sizeof(*header) / 4);
97 nvram_len = ((struct nvram_header *)(nvram_buf))->len;
98 if (nvram_len > size) {
99 pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n");
100 nvram_len = size;
101 }
102 if (nvram_len >= NVRAM_SPACE) {
103 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
104 nvram_len, NVRAM_SPACE - 1);
105 nvram_len = NVRAM_SPACE - 1;
106 }
107 /* proceed reading data after header */
108 __ioread32_copy(nvram_buf + sizeof(*header), header + 1,
109 DIV_ROUND_UP(nvram_len, 4));
110 nvram_buf[NVRAM_SPACE - 1] = '\0';
111
112 return 0;
113}
114
115/*
116 * On bcm47xx we need access to the NVRAM very early, so we can't use mtd
117 * subsystem to access flash. We can't even use platform device / driver to
118 * store memory offset.
119 * To handle this we provide following symbol. It's supposed to be called as
120 * soon as we get info about flash device, before any NVRAM entry is needed.
121 */
122int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
123{
124 void __iomem *iobase;
125 int err;
126
127 iobase = ioremap_nocache(base, lim);
128 if (!iobase)
129 return -ENOMEM;
130
131 err = nvram_find_and_copy(iobase, lim);
132
133 iounmap(iobase);
134
135 return err;
136}
137
138static int nvram_init(void)
139{
140#ifdef CONFIG_MTD
141 struct mtd_info *mtd;
142 struct nvram_header header;
143 size_t bytes_read;
144 int err;
145
146 mtd = get_mtd_device_nm("nvram");
147 if (IS_ERR(mtd))
148 return -ENODEV;
149
150 err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (uint8_t *)&header);
151 if (!err && header.magic == NVRAM_MAGIC &&
152 header.len > sizeof(header)) {
153 nvram_len = header.len;
154 if (nvram_len >= NVRAM_SPACE) {
155 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
156 header.len, NVRAM_SPACE);
157 nvram_len = NVRAM_SPACE - 1;
158 }
159
160 err = mtd_read(mtd, 0, nvram_len, &nvram_len,
161 (u8 *)nvram_buf);
162 return err;
163 }
164#endif
165
166 return -ENXIO;
167}
168
169int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
170{
171 char *var, *value, *end, *eq;
172 int err;
173
174 if (!name)
175 return -EINVAL;
176
177 if (!nvram_len) {
178 err = nvram_init();
179 if (err)
180 return err;
181 }
182
183 /* Look for name=value and return value */
184 var = &nvram_buf[sizeof(struct nvram_header)];
185 end = nvram_buf + sizeof(nvram_buf);
186 while (var < end && *var) {
187 eq = strchr(var, '=');
188 if (!eq)
189 break;
190 value = eq + 1;
191 if (eq - var == strlen(name) &&
192 strncmp(var, name, eq - var) == 0)
193 return snprintf(val, val_len, "%s", value);
194 var = value + strlen(value) + 1;
195 }
196 return -ENOENT;
197}
198EXPORT_SYMBOL(bcm47xx_nvram_getenv);
199
200int bcm47xx_nvram_gpio_pin(const char *name)
201{
202 int i, err;
203 char nvram_var[] = "gpioXX";
204 char buf[NVRAM_MAX_GPIO_VALUE_LEN];
205
206 /* TODO: Optimize it to don't call getenv so many times */
207 for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) {
208 err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
209 if (err <= 0)
210 continue;
211 err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
212 if (err <= 0)
213 continue;
214 if (!strcmp(name, buf))
215 return i;
216 }
217 return -ENOENT;
218}
219EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
220
221char *bcm47xx_nvram_get_contents(size_t *nvram_size)
222{
223 int err;
224 char *nvram;
225
226 if (!nvram_len) {
227 err = nvram_init();
228 if (err)
229 return NULL;
230 }
231
232 *nvram_size = nvram_len - sizeof(struct nvram_header);
233 nvram = vmalloc(*nvram_size);
234 if (!nvram)
235 return NULL;
236 memcpy(nvram, &nvram_buf[sizeof(struct nvram_header)], *nvram_size);
237
238 return nvram;
239}
240EXPORT_SYMBOL(bcm47xx_nvram_get_contents);
241
242MODULE_LICENSE("GPL v2");