1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl> 4 */ 5 6 #include <linux/bcm47xx_nvram.h> 7 #include <linux/etherdevice.h> 8 #include <linux/hex.h> 9 #include <linux/if_ether.h> 10 #include <linux/io.h> 11 #include <linux/module.h> 12 #include <linux/nvmem-consumer.h> 13 #include <linux/nvmem-provider.h> 14 #include <linux/of.h> 15 #include <linux/platform_device.h> 16 #include <linux/slab.h> 17 18 #define NVRAM_MAGIC "FLSH" 19 20 /** 21 * struct brcm_nvram - driver state internal struct 22 * 23 * @dev: NVMEM device pointer 24 * @nvmem_size: Size of the whole space available for NVRAM 25 * @data: NVRAM data copy stored to avoid poking underlying flash controller 26 * @data_len: NVRAM data size 27 * @padding_byte: Padding value used to fill remaining space 28 * @cells: Array of discovered NVMEM cells 29 * @ncells: Number of elements in cells 30 */ 31 struct brcm_nvram { 32 struct device *dev; 33 size_t nvmem_size; 34 uint8_t *data; 35 size_t data_len; 36 uint8_t padding_byte; 37 struct nvmem_cell_info *cells; 38 int ncells; 39 }; 40 41 struct brcm_nvram_header { 42 char magic[4]; 43 __le32 len; 44 __le32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */ 45 __le32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */ 46 __le32 config_ncdl; /* ncdl values for memc */ 47 }; 48 49 static int brcm_nvram_read(void *context, unsigned int offset, void *val, 50 size_t bytes) 51 { 52 struct brcm_nvram *priv = context; 53 size_t to_copy; 54 55 if (offset + bytes > priv->data_len) 56 to_copy = max_t(ssize_t, (ssize_t)priv->data_len - offset, 0); 57 else 58 to_copy = bytes; 59 60 memcpy(val, priv->data + offset, to_copy); 61 62 memset((uint8_t *)val + to_copy, priv->padding_byte, bytes - to_copy); 63 64 return 0; 65 } 66 67 static int brcm_nvram_copy_data(struct brcm_nvram *priv, struct platform_device *pdev) 68 { 69 struct resource *res; 70 void __iomem *base; 71 72 base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); 73 if (IS_ERR(base)) 74 return PTR_ERR(base); 75 76 priv->nvmem_size = resource_size(res); 77 78 priv->padding_byte = readb(base + priv->nvmem_size - 1); 79 for (priv->data_len = priv->nvmem_size; 80 priv->data_len; 81 priv->data_len--) { 82 if (readb(base + priv->data_len - 1) != priv->padding_byte) 83 break; 84 } 85 WARN(priv->data_len > SZ_128K, "Unexpected (big) NVRAM size: %zu B\n", priv->data_len); 86 87 if (priv->data_len < sizeof(struct brcm_nvram_header)) { 88 dev_err(priv->dev, "NVRAM data too small (%zu)\n", priv->data_len); 89 return -EINVAL; 90 } 91 92 priv->data = devm_kzalloc(priv->dev, priv->data_len, GFP_KERNEL); 93 if (!priv->data) 94 return -ENOMEM; 95 96 memcpy_fromio(priv->data, base, priv->data_len); 97 98 bcm47xx_nvram_init_from_iomem(base, priv->data_len); 99 100 return 0; 101 } 102 103 static int brcm_nvram_read_post_process_macaddr(void *context, const char *id, int index, 104 unsigned int offset, void *buf, size_t bytes) 105 { 106 u8 mac[ETH_ALEN]; 107 108 if (bytes != MAC_ADDR_STR_LEN) 109 return -EINVAL; 110 111 if (!mac_pton(buf, mac)) 112 return -EINVAL; 113 114 if (index) 115 eth_addr_add(mac, index); 116 117 ether_addr_copy(buf, mac); 118 119 return 0; 120 } 121 122 static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data, 123 size_t len) 124 { 125 struct device *dev = priv->dev; 126 char *var, *value; 127 uint8_t tmp; 128 int idx; 129 int err = 0; 130 131 tmp = priv->data[len - 1]; 132 priv->data[len - 1] = '\0'; 133 134 priv->ncells = 0; 135 for (var = data + sizeof(struct brcm_nvram_header); 136 var < (char *)data + len && *var; 137 var += strlen(var) + 1) { 138 priv->ncells++; 139 } 140 141 priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL); 142 if (!priv->cells) { 143 err = -ENOMEM; 144 goto out; 145 } 146 147 for (var = data + sizeof(struct brcm_nvram_header), idx = 0; 148 var < (char *)data + len && *var; 149 var = value + strlen(value) + 1, idx++) { 150 char *eq, *name; 151 152 eq = strchr(var, '='); 153 if (!eq) 154 break; 155 *eq = '\0'; 156 name = devm_kstrdup(dev, var, GFP_KERNEL); 157 *eq = '='; 158 if (!name) { 159 err = -ENOMEM; 160 goto out; 161 } 162 value = eq + 1; 163 164 priv->cells[idx].name = name; 165 priv->cells[idx].offset = value - (char *)data; 166 priv->cells[idx].bytes = strlen(value); 167 priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name); 168 if (!strcmp(name, "et0macaddr") || 169 !strcmp(name, "et1macaddr") || 170 !strcmp(name, "et2macaddr")) { 171 priv->cells[idx].raw_len = strlen(value); 172 priv->cells[idx].bytes = ETH_ALEN; 173 priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr; 174 } 175 } 176 177 out: 178 priv->data[len - 1] = tmp; 179 return err; 180 } 181 182 static int brcm_nvram_parse(struct brcm_nvram *priv) 183 { 184 struct brcm_nvram_header *header = (struct brcm_nvram_header *)priv->data; 185 struct device *dev = priv->dev; 186 size_t len; 187 int err; 188 189 if (memcmp(header->magic, NVRAM_MAGIC, 4)) { 190 dev_err(dev, "Invalid NVRAM magic\n"); 191 return -EINVAL; 192 } 193 194 len = le32_to_cpu(header->len); 195 if (len < sizeof(*header)) { 196 dev_err(dev, "NVRAM length (%zd) too small\n", len); 197 return -EINVAL; 198 } 199 if (len > priv->data_len) { 200 dev_err(dev, "NVRAM length (%zd) exceeds data size (%zd)\n", len, 201 priv->data_len); 202 return -EINVAL; 203 } 204 205 err = brcm_nvram_add_cells(priv, priv->data, len); 206 if (err) 207 dev_err(dev, "Failed to add cells: %d\n", err); 208 209 return 0; 210 } 211 212 static int brcm_nvram_probe(struct platform_device *pdev) 213 { 214 struct nvmem_config config = { 215 .name = "brcm-nvram", 216 .reg_read = brcm_nvram_read, 217 }; 218 struct device *dev = &pdev->dev; 219 struct brcm_nvram *priv; 220 int err; 221 222 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 223 if (!priv) 224 return -ENOMEM; 225 priv->dev = dev; 226 227 err = brcm_nvram_copy_data(priv, pdev); 228 if (err) 229 return err; 230 231 err = brcm_nvram_parse(priv); 232 if (err) 233 return err; 234 235 config.dev = dev; 236 config.cells = priv->cells; 237 config.ncells = priv->ncells; 238 config.priv = priv; 239 config.size = priv->nvmem_size; 240 241 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); 242 } 243 244 static const struct of_device_id brcm_nvram_of_match_table[] = { 245 { .compatible = "brcm,nvram", }, 246 {}, 247 }; 248 249 static struct platform_driver brcm_nvram_driver = { 250 .probe = brcm_nvram_probe, 251 .driver = { 252 .name = "brcm_nvram", 253 .of_match_table = brcm_nvram_of_match_table, 254 }, 255 }; 256 257 static int __init brcm_nvram_init(void) 258 { 259 return platform_driver_register(&brcm_nvram_driver); 260 } 261 262 subsys_initcall_sync(brcm_nvram_init); 263 264 MODULE_AUTHOR("Rafał Miłecki"); 265 MODULE_DESCRIPTION("Broadcom I/O-mapped NVRAM support driver"); 266 MODULE_LICENSE("GPL"); 267 MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table); 268