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 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 */ 122 int 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 } 137 138 static 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 } 168 169 int 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 } 198 EXPORT_SYMBOL(bcm47xx_nvram_getenv); 199 200 int 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 } 219 EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin); 220 221 char *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 } 240 EXPORT_SYMBOL(bcm47xx_nvram_get_contents); 241 242 MODULE_LICENSE("GPL v2"); 243