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/io.h> 8 #include <linux/mod_devicetable.h> 9 #include <linux/module.h> 10 #include <linux/nvmem-consumer.h> 11 #include <linux/nvmem-provider.h> 12 #include <linux/of.h> 13 #include <linux/platform_device.h> 14 #include <linux/slab.h> 15 16 #define NVRAM_MAGIC "FLSH" 17 18 struct brcm_nvram { 19 struct device *dev; 20 void __iomem *base; 21 struct nvmem_cell_info *cells; 22 int ncells; 23 }; 24 25 struct brcm_nvram_header { 26 char magic[4]; 27 __le32 len; 28 __le32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */ 29 __le32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */ 30 __le32 config_ncdl; /* ncdl values for memc */ 31 }; 32 33 static int brcm_nvram_read(void *context, unsigned int offset, void *val, 34 size_t bytes) 35 { 36 struct brcm_nvram *priv = context; 37 u8 *dst = val; 38 39 while (bytes--) 40 *dst++ = readb(priv->base + offset++); 41 42 return 0; 43 } 44 45 static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data, 46 size_t len) 47 { 48 struct device *dev = priv->dev; 49 char *var, *value, *eq; 50 int idx; 51 52 priv->ncells = 0; 53 for (var = data + sizeof(struct brcm_nvram_header); 54 var < (char *)data + len && *var; 55 var += strlen(var) + 1) { 56 priv->ncells++; 57 } 58 59 priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL); 60 if (!priv->cells) 61 return -ENOMEM; 62 63 for (var = data + sizeof(struct brcm_nvram_header), idx = 0; 64 var < (char *)data + len && *var; 65 var = value + strlen(value) + 1, idx++) { 66 eq = strchr(var, '='); 67 if (!eq) 68 break; 69 *eq = '\0'; 70 value = eq + 1; 71 72 priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL); 73 if (!priv->cells[idx].name) 74 return -ENOMEM; 75 priv->cells[idx].offset = value - (char *)data; 76 priv->cells[idx].bytes = strlen(value); 77 priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name); 78 } 79 80 return 0; 81 } 82 83 static int brcm_nvram_parse(struct brcm_nvram *priv) 84 { 85 struct device *dev = priv->dev; 86 struct brcm_nvram_header header; 87 uint8_t *data; 88 size_t len; 89 int err; 90 91 memcpy_fromio(&header, priv->base, sizeof(header)); 92 93 if (memcmp(header.magic, NVRAM_MAGIC, 4)) { 94 dev_err(dev, "Invalid NVRAM magic\n"); 95 return -EINVAL; 96 } 97 98 len = le32_to_cpu(header.len); 99 100 data = kzalloc(len, GFP_KERNEL); 101 if (!data) 102 return -ENOMEM; 103 104 memcpy_fromio(data, priv->base, len); 105 data[len - 1] = '\0'; 106 107 err = brcm_nvram_add_cells(priv, data, len); 108 if (err) { 109 dev_err(dev, "Failed to add cells: %d\n", err); 110 return err; 111 } 112 113 kfree(data); 114 115 return 0; 116 } 117 118 static int brcm_nvram_probe(struct platform_device *pdev) 119 { 120 struct nvmem_config config = { 121 .name = "brcm-nvram", 122 .reg_read = brcm_nvram_read, 123 }; 124 struct device *dev = &pdev->dev; 125 struct resource *res; 126 struct brcm_nvram *priv; 127 int err; 128 129 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 130 if (!priv) 131 return -ENOMEM; 132 priv->dev = dev; 133 134 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 135 priv->base = devm_ioremap_resource(dev, res); 136 if (IS_ERR(priv->base)) 137 return PTR_ERR(priv->base); 138 139 err = brcm_nvram_parse(priv); 140 if (err) 141 return err; 142 143 bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res)); 144 145 config.dev = dev; 146 config.cells = priv->cells; 147 config.ncells = priv->ncells; 148 config.priv = priv; 149 config.size = resource_size(res); 150 151 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); 152 } 153 154 static const struct of_device_id brcm_nvram_of_match_table[] = { 155 { .compatible = "brcm,nvram", }, 156 {}, 157 }; 158 159 static struct platform_driver brcm_nvram_driver = { 160 .probe = brcm_nvram_probe, 161 .driver = { 162 .name = "brcm_nvram", 163 .of_match_table = brcm_nvram_of_match_table, 164 }, 165 }; 166 167 static int __init brcm_nvram_init(void) 168 { 169 return platform_driver_register(&brcm_nvram_driver); 170 } 171 172 subsys_initcall_sync(brcm_nvram_init); 173 174 MODULE_AUTHOR("Rafał Miłecki"); 175 MODULE_LICENSE("GPL"); 176 MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table); 177