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 size_t nvram_len; 39 static const u32 nvram_sizes[] = {0x8000, 0xF000, 0x10000}; 40 41 static 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 */ 56 static int nvram_find_and_copy(void __iomem *iobase, u32 lim) 57 { 58 struct nvram_header __iomem *header; 59 int i; 60 u32 off; 61 u32 *src, *dst; 62 u32 size; 63 64 if (nvram_len) { 65 pr_warn("nvram already initialized\n"); 66 return -EEXIST; 67 } 68 69 /* TODO: when nvram is on nand flash check for bad blocks first. */ 70 off = FLASH_MIN; 71 while (off <= lim) { 72 /* Windowed flash access */ 73 size = find_nvram_size(iobase + off); 74 if (size) { 75 header = (struct nvram_header *)(iobase + off - size); 76 goto found; 77 } 78 off <<= 1; 79 } 80 81 /* Try embedded NVRAM at 4 KB and 1 KB as last resorts */ 82 header = (struct nvram_header *)(iobase + 4096); 83 if (header->magic == NVRAM_MAGIC) { 84 size = NVRAM_SPACE; 85 goto found; 86 } 87 88 header = (struct nvram_header *)(iobase + 1024); 89 if (header->magic == NVRAM_MAGIC) { 90 size = NVRAM_SPACE; 91 goto found; 92 } 93 94 pr_err("no nvram found\n"); 95 return -ENXIO; 96 97 found: 98 src = (u32 *)header; 99 dst = (u32 *)nvram_buf; 100 for (i = 0; i < sizeof(struct nvram_header); i += 4) 101 *dst++ = __raw_readl(src++); 102 header = (struct nvram_header *)nvram_buf; 103 nvram_len = header->len; 104 if (nvram_len > size) { 105 pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n"); 106 nvram_len = size; 107 } 108 if (nvram_len >= NVRAM_SPACE) { 109 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n", 110 header->len, NVRAM_SPACE - 1); 111 nvram_len = NVRAM_SPACE - 1; 112 } 113 /* proceed reading data after header */ 114 for (; i < nvram_len; i += 4) 115 *dst++ = readl(src++); 116 nvram_buf[NVRAM_SPACE - 1] = '\0'; 117 118 return 0; 119 } 120 121 /* 122 * On bcm47xx we need access to the NVRAM very early, so we can't use mtd 123 * subsystem to access flash. We can't even use platform device / driver to 124 * store memory offset. 125 * To handle this we provide following symbol. It's supposed to be called as 126 * soon as we get info about flash device, before any NVRAM entry is needed. 127 */ 128 int bcm47xx_nvram_init_from_mem(u32 base, u32 lim) 129 { 130 void __iomem *iobase; 131 int err; 132 133 iobase = ioremap_nocache(base, lim); 134 if (!iobase) 135 return -ENOMEM; 136 137 err = nvram_find_and_copy(iobase, lim); 138 139 iounmap(iobase); 140 141 return err; 142 } 143 144 static int nvram_init(void) 145 { 146 #ifdef CONFIG_MTD 147 struct mtd_info *mtd; 148 struct nvram_header header; 149 size_t bytes_read; 150 int err; 151 152 mtd = get_mtd_device_nm("nvram"); 153 if (IS_ERR(mtd)) 154 return -ENODEV; 155 156 err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (uint8_t *)&header); 157 if (!err && header.magic == NVRAM_MAGIC && 158 header.len > sizeof(header)) { 159 nvram_len = header.len; 160 if (nvram_len >= NVRAM_SPACE) { 161 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n", 162 header.len, NVRAM_SPACE); 163 nvram_len = NVRAM_SPACE - 1; 164 } 165 166 err = mtd_read(mtd, 0, nvram_len, &nvram_len, 167 (u8 *)nvram_buf); 168 return err; 169 } 170 #endif 171 172 return -ENXIO; 173 } 174 175 int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len) 176 { 177 char *var, *value, *end, *eq; 178 int err; 179 180 if (!name) 181 return -EINVAL; 182 183 if (!nvram_len) { 184 err = nvram_init(); 185 if (err) 186 return err; 187 } 188 189 /* Look for name=value and return value */ 190 var = &nvram_buf[sizeof(struct nvram_header)]; 191 end = nvram_buf + sizeof(nvram_buf); 192 while (var < end && *var) { 193 eq = strchr(var, '='); 194 if (!eq) 195 break; 196 value = eq + 1; 197 if (eq - var == strlen(name) && 198 strncmp(var, name, eq - var) == 0) 199 return snprintf(val, val_len, "%s", value); 200 var = value + strlen(value) + 1; 201 } 202 return -ENOENT; 203 } 204 EXPORT_SYMBOL(bcm47xx_nvram_getenv); 205 206 int bcm47xx_nvram_gpio_pin(const char *name) 207 { 208 int i, err; 209 char nvram_var[] = "gpioXX"; 210 char buf[NVRAM_MAX_GPIO_VALUE_LEN]; 211 212 /* TODO: Optimize it to don't call getenv so many times */ 213 for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) { 214 err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i); 215 if (err <= 0) 216 continue; 217 err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf)); 218 if (err <= 0) 219 continue; 220 if (!strcmp(name, buf)) 221 return i; 222 } 223 return -ENOENT; 224 } 225 EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin); 226 227 char *bcm47xx_nvram_get_contents(size_t *nvram_size) 228 { 229 int err; 230 char *nvram; 231 232 if (!nvram_len) { 233 err = nvram_init(); 234 if (err) 235 return NULL; 236 } 237 238 *nvram_size = nvram_len - sizeof(struct nvram_header); 239 nvram = vmalloc(*nvram_size); 240 if (!nvram) 241 return NULL; 242 memcpy(nvram, &nvram_buf[sizeof(struct nvram_header)], *nvram_size); 243 244 return nvram; 245 } 246 EXPORT_SYMBOL(bcm47xx_nvram_get_contents); 247 248 MODULE_LICENSE("GPL v2"); 249