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/if_ether.h> 9 #include <linux/io.h> 10 #include <linux/mod_devicetable.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 underlaying 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 priv->data = devm_kzalloc(priv->dev, priv->data_len, GFP_KERNEL); 88 if (!priv->data) 89 return -ENOMEM; 90 91 memcpy_fromio(priv->data, base, priv->data_len); 92 93 bcm47xx_nvram_init_from_iomem(base, priv->data_len); 94 95 return 0; 96 } 97 98 static int brcm_nvram_read_post_process_macaddr(void *context, const char *id, int index, 99 unsigned int offset, void *buf, size_t bytes) 100 { 101 u8 mac[ETH_ALEN]; 102 103 if (bytes != 3 * ETH_ALEN - 1) 104 return -EINVAL; 105 106 if (!mac_pton(buf, mac)) 107 return -EINVAL; 108 109 if (index) 110 eth_addr_add(mac, index); 111 112 ether_addr_copy(buf, mac); 113 114 return 0; 115 } 116 117 static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data, 118 size_t len) 119 { 120 struct device *dev = priv->dev; 121 char *var, *value; 122 uint8_t tmp; 123 int idx; 124 int err = 0; 125 126 tmp = priv->data[len - 1]; 127 priv->data[len - 1] = '\0'; 128 129 priv->ncells = 0; 130 for (var = data + sizeof(struct brcm_nvram_header); 131 var < (char *)data + len && *var; 132 var += strlen(var) + 1) { 133 priv->ncells++; 134 } 135 136 priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL); 137 if (!priv->cells) { 138 err = -ENOMEM; 139 goto out; 140 } 141 142 for (var = data + sizeof(struct brcm_nvram_header), idx = 0; 143 var < (char *)data + len && *var; 144 var = value + strlen(value) + 1, idx++) { 145 char *eq, *name; 146 147 eq = strchr(var, '='); 148 if (!eq) 149 break; 150 *eq = '\0'; 151 name = devm_kstrdup(dev, var, GFP_KERNEL); 152 *eq = '='; 153 if (!name) { 154 err = -ENOMEM; 155 goto out; 156 } 157 value = eq + 1; 158 159 priv->cells[idx].name = name; 160 priv->cells[idx].offset = value - (char *)data; 161 priv->cells[idx].bytes = strlen(value); 162 priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name); 163 if (!strcmp(name, "et0macaddr") || 164 !strcmp(name, "et1macaddr") || 165 !strcmp(name, "et2macaddr")) { 166 priv->cells[idx].raw_len = strlen(value); 167 priv->cells[idx].bytes = ETH_ALEN; 168 priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr; 169 } 170 } 171 172 out: 173 priv->data[len - 1] = tmp; 174 return err; 175 } 176 177 static int brcm_nvram_parse(struct brcm_nvram *priv) 178 { 179 struct brcm_nvram_header *header = (struct brcm_nvram_header *)priv->data; 180 struct device *dev = priv->dev; 181 size_t len; 182 int err; 183 184 if (memcmp(header->magic, NVRAM_MAGIC, 4)) { 185 dev_err(dev, "Invalid NVRAM magic\n"); 186 return -EINVAL; 187 } 188 189 len = le32_to_cpu(header->len); 190 if (len > priv->nvmem_size) { 191 dev_err(dev, "NVRAM length (%zd) exceeds mapped size (%zd)\n", len, 192 priv->nvmem_size); 193 return -EINVAL; 194 } 195 196 err = brcm_nvram_add_cells(priv, priv->data, len); 197 if (err) 198 dev_err(dev, "Failed to add cells: %d\n", err); 199 200 return 0; 201 } 202 203 static int brcm_nvram_probe(struct platform_device *pdev) 204 { 205 struct nvmem_config config = { 206 .name = "brcm-nvram", 207 .reg_read = brcm_nvram_read, 208 }; 209 struct device *dev = &pdev->dev; 210 struct brcm_nvram *priv; 211 int err; 212 213 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 214 if (!priv) 215 return -ENOMEM; 216 priv->dev = dev; 217 218 err = brcm_nvram_copy_data(priv, pdev); 219 if (err) 220 return err; 221 222 err = brcm_nvram_parse(priv); 223 if (err) 224 return err; 225 226 config.dev = dev; 227 config.cells = priv->cells; 228 config.ncells = priv->ncells; 229 config.priv = priv; 230 config.size = priv->nvmem_size; 231 232 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); 233 } 234 235 static const struct of_device_id brcm_nvram_of_match_table[] = { 236 { .compatible = "brcm,nvram", }, 237 {}, 238 }; 239 240 static struct platform_driver brcm_nvram_driver = { 241 .probe = brcm_nvram_probe, 242 .driver = { 243 .name = "brcm_nvram", 244 .of_match_table = brcm_nvram_of_match_table, 245 }, 246 }; 247 248 static int __init brcm_nvram_init(void) 249 { 250 return platform_driver_register(&brcm_nvram_driver); 251 } 252 253 subsys_initcall_sync(brcm_nvram_init); 254 255 MODULE_AUTHOR("Rafał Miłecki"); 256 MODULE_LICENSE("GPL"); 257 MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table); 258