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 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 95 found: 96 __ioread32_copy(nvram_buf, header, sizeof(*header) / 4); 97 header = (struct nvram_header *)nvram_buf; 98 nvram_len = header->len; 99 if (nvram_len > size) { 100 pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n"); 101 nvram_len = size; 102 } 103 if (nvram_len >= NVRAM_SPACE) { 104 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n", 105 header->len, NVRAM_SPACE - 1); 106 nvram_len = NVRAM_SPACE - 1; 107 } 108 /* proceed reading data after header */ 109 __ioread32_copy(nvram_buf + sizeof(*header), header + 1, 110 DIV_ROUND_UP(nvram_len, 4)); 111 nvram_buf[NVRAM_SPACE - 1] = '\0'; 112 113 return 0; 114 } 115 116 /* 117 * On bcm47xx we need access to the NVRAM very early, so we can't use mtd 118 * subsystem to access flash. We can't even use platform device / driver to 119 * store memory offset. 120 * To handle this we provide following symbol. It's supposed to be called as 121 * soon as we get info about flash device, before any NVRAM entry is needed. 122 */ 123 int bcm47xx_nvram_init_from_mem(u32 base, u32 lim) 124 { 125 void __iomem *iobase; 126 int err; 127 128 iobase = ioremap_nocache(base, lim); 129 if (!iobase) 130 return -ENOMEM; 131 132 err = nvram_find_and_copy(iobase, lim); 133 134 iounmap(iobase); 135 136 return err; 137 } 138 139 static int nvram_init(void) 140 { 141 #ifdef CONFIG_MTD 142 struct mtd_info *mtd; 143 struct nvram_header header; 144 size_t bytes_read; 145 int err; 146 147 mtd = get_mtd_device_nm("nvram"); 148 if (IS_ERR(mtd)) 149 return -ENODEV; 150 151 err = mtd_read(mtd, 0, sizeof(header), &bytes_read, (uint8_t *)&header); 152 if (!err && header.magic == NVRAM_MAGIC && 153 header.len > sizeof(header)) { 154 nvram_len = header.len; 155 if (nvram_len >= NVRAM_SPACE) { 156 pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n", 157 header.len, NVRAM_SPACE); 158 nvram_len = NVRAM_SPACE - 1; 159 } 160 161 err = mtd_read(mtd, 0, nvram_len, &nvram_len, 162 (u8 *)nvram_buf); 163 return err; 164 } 165 #endif 166 167 return -ENXIO; 168 } 169 170 int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len) 171 { 172 char *var, *value, *end, *eq; 173 int err; 174 175 if (!name) 176 return -EINVAL; 177 178 if (!nvram_len) { 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); 187 while (var < end && *var) { 188 eq = strchr(var, '='); 189 if (!eq) 190 break; 191 value = eq + 1; 192 if (eq - var == strlen(name) && 193 strncmp(var, name, eq - var) == 0) 194 return snprintf(val, val_len, "%s", value); 195 var = value + strlen(value) + 1; 196 } 197 return -ENOENT; 198 } 199 EXPORT_SYMBOL(bcm47xx_nvram_getenv); 200 201 int bcm47xx_nvram_gpio_pin(const char *name) 202 { 203 int i, err; 204 char nvram_var[] = "gpioXX"; 205 char buf[NVRAM_MAX_GPIO_VALUE_LEN]; 206 207 /* TODO: Optimize it to don't call getenv so many times */ 208 for (i = 0; i < NVRAM_MAX_GPIO_ENTRIES; i++) { 209 err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i); 210 if (err <= 0) 211 continue; 212 err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf)); 213 if (err <= 0) 214 continue; 215 if (!strcmp(name, buf)) 216 return i; 217 } 218 return -ENOENT; 219 } 220 EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin); 221 222 char *bcm47xx_nvram_get_contents(size_t *nvram_size) 223 { 224 int err; 225 char *nvram; 226 227 if (!nvram_len) { 228 err = nvram_init(); 229 if (err) 230 return NULL; 231 } 232 233 *nvram_size = nvram_len - sizeof(struct nvram_header); 234 nvram = vmalloc(*nvram_size); 235 if (!nvram) 236 return NULL; 237 memcpy(nvram, &nvram_buf[sizeof(struct nvram_header)], *nvram_size); 238 239 return nvram; 240 } 241 EXPORT_SYMBOL(bcm47xx_nvram_get_contents); 242 243 MODULE_LICENSE("GPL v2"); 244