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 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 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 *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 */ 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(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; 106 107 found: 108 bcm47xx_nvram_copy(flash_start + offset, 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_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(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 } 153 154 static 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 } 184 185 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(val, val_len, "%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(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 } 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(*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