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
29 struct 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
37 static char nvram_buf[NVRAM_SPACE];
38 static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000};
39
find_nvram_size(void __iomem * end)40 static u32 find_nvram_size(void __iomem *end)
41 {
42 struct nvram_header __iomem *header;
43 int i;
44
45 for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
46 header = (struct nvram_header *)(end - nvram_sizes[i]);
47 if (header->magic == NVRAM_MAGIC)
48 return nvram_sizes[i];
49 }
50
51 return 0;
52 }
53
54 /* Probe for NVRAM header */
nvram_find_and_copy(void __iomem * iobase,u32 lim)55 static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
56 {
57 struct nvram_header __iomem *header;
58 int i;
59 u32 off;
60 u32 *src, *dst;
61 u32 size;
62
63 if (nvram_buf[0]) {
64 pr_warn("nvram already initialized\n");
65 return -EEXIST;
66 }
67
68 /* TODO: when nvram is on nand flash check for bad blocks first. */
69 off = FLASH_MIN;
70 while (off <= lim) {
71 /* Windowed flash access */
72 size = find_nvram_size(iobase + off);
73 if (size) {
74 header = (struct nvram_header *)(iobase + off - size);
75 goto found;
76 }
77 off <<= 1;
78 }
79
80 /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */
81 header = (struct nvram_header *)(iobase + 4096);
82 if (header->magic == NVRAM_MAGIC) {
83 size = NVRAM_SPACE;
84 goto found;
85 }
86
87 header = (struct nvram_header *)(iobase + 1024);
88 if (header->magic == NVRAM_MAGIC) {
89 size = NVRAM_SPACE;
90 goto found;
91 }
92
93 pr_err("no nvram found\n");
94 return -ENXIO;
95
96 found:
97 if (header->len > size)
98 pr_err("The nvram size accoridng to the header seems to be bigger than the partition on flash\n");
99 if (header->len > NVRAM_SPACE)
100 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
101 header->len, NVRAM_SPACE);
102
103 src = (u32 *)header;
104 dst = (u32 *)nvram_buf;
105 for (i = 0; i < sizeof(struct nvram_header); i += 4)
106 *dst++ = __raw_readl(src++);
107 for (; i < header->len && i < NVRAM_SPACE && i < size; i += 4)
108 *dst++ = readl(src++);
109
110 return 0;
111 }
112
113 /*
114 * On bcm47xx we need access to the NVRAM very early, so we can't use mtd
115 * subsystem to access flash. We can't even use platform device / driver to
116 * store memory offset.
117 * To handle this we provide following symbol. It's supposed to be called as
118 * soon as we get info about flash device, before any NVRAM entry is needed.
119 */
bcm47xx_nvram_init_from_mem(u32 base,u32 lim)120 int bcm47xx_nvram_init_from_mem(u32 base, u32 lim)
121 {
122 void __iomem *iobase;
123 int err;
124
125 iobase = ioremap_nocache(base, lim);
126 if (!iobase)
127 return -ENOMEM;
128
129 err = nvram_find_and_copy(iobase, lim);
130
131 iounmap(iobase);
132
133 return err;
134 }
135
nvram_init(void)136 static int nvram_init(void)
137 {
138 #ifdef CONFIG_MTD
139 struct mtd_info *mtd;
140 struct nvram_header header;
141 size_t bytes_read;
142 int err;
143
144 mtd = get_mtd_device_nm("nvram");
145 if (IS_ERR(mtd))
146 return -ENODEV;
147
148 err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (uint8_t *)&header);
149 if (!err && header.magic == NVRAM_MAGIC) {
150 u8 *dst = (uint8_t *)nvram_buf;
151 size_t len = header.len;
152
153 if (header.len > NVRAM_SPACE) {
154 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
155 header.len, NVRAM_SPACE);
156 len = NVRAM_SPACE;
157 }
158
159 err = mtd_read(mtd, 0, len, &bytes_read, dst);
160 if (err)
161 return err;
162
163 return 0;
164 }
165 #endif
166
167 return -ENXIO;
168 }
169
bcm47xx_nvram_getenv(const char * name,char * val,size_t val_len)170 int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len)
171 {
172 char *var, *value, *end, *eq;
173 int data_left, err;
174
175 if (!name)
176 return -EINVAL;
177
178 if (!nvram_buf[0]) {
179 err = nvram_init();
180 if (err)
181 return err;
182 }
183
184 /* Look for name=value and return value */
185 var = &nvram_buf[sizeof(struct nvram_header)];
186 end = nvram_buf + sizeof(nvram_buf) - 2;
187 end[0] = '\0';
188 end[1] = '\0';
189 for (; *var; var = value + strlen(value) + 1) {
190 data_left = end - var;
191
192 eq = strnchr(var, data_left, '=');
193 if (!eq)
194 break;
195 value = eq + 1;
196 if (eq - var == strlen(name) &&
197 strncmp(var, name, eq - var) == 0)
198 return snprintf(val, val_len, "%s", value);
199 }
200 return -ENOENT;
201 }
202 EXPORT_SYMBOL(bcm47xx_nvram_getenv);
203
bcm47xx_nvram_gpio_pin(const char * name)204 int bcm47xx_nvram_gpio_pin(const char *name)
205 {
206 int i, err;
207 char nvram_var[] = "gpioXX";
208 char buf[NVRAM_MAX_GPIO_VALUE_LEN];
209
210 /* TODO: Optimize it to don't call getenv so many times */
211 for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) {
212 err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
213 if (err <= 0)
214 continue;
215 err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
216 if (err <= 0)
217 continue;
218 if (!strcmp(name, buf))
219 return i;
220 }
221 return -ENOENT;
222 }
223 EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);
224