1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl> 4 */ 5 6 #include <linux/io.h> 7 #include <linux/mod_devicetable.h> 8 #include <linux/module.h> 9 #include <linux/nvmem-consumer.h> 10 #include <linux/nvmem-provider.h> 11 #include <linux/platform_device.h> 12 #include <linux/slab.h> 13 14 #define NVRAM_MAGIC "FLSH" 15 16 struct brcm_nvram { 17 struct device *dev; 18 void __iomem *base; 19 struct nvmem_cell_info *cells; 20 int ncells; 21 }; 22 23 struct brcm_nvram_header { 24 char magic[4]; 25 __le32 len; 26 __le32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */ 27 __le32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */ 28 __le32 config_ncdl; /* ncdl values for memc */ 29 }; 30 31 static int brcm_nvram_read(void *context, unsigned int offset, void *val, 32 size_t bytes) 33 { 34 struct brcm_nvram *priv = context; 35 u8 *dst = val; 36 37 while (bytes--) 38 *dst++ = readb(priv->base + offset++); 39 40 return 0; 41 } 42 43 static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data, 44 size_t len) 45 { 46 struct device *dev = priv->dev; 47 char *var, *value, *eq; 48 int idx; 49 50 priv->ncells = 0; 51 for (var = data + sizeof(struct brcm_nvram_header); 52 var < (char *)data + len && *var; 53 var += strlen(var) + 1) { 54 priv->ncells++; 55 } 56 57 priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL); 58 if (!priv->cells) 59 return -ENOMEM; 60 61 for (var = data + sizeof(struct brcm_nvram_header), idx = 0; 62 var < (char *)data + len && *var; 63 var = value + strlen(value) + 1, idx++) { 64 eq = strchr(var, '='); 65 if (!eq) 66 break; 67 *eq = '\0'; 68 value = eq + 1; 69 70 priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL); 71 if (!priv->cells[idx].name) 72 return -ENOMEM; 73 priv->cells[idx].offset = value - (char *)data; 74 priv->cells[idx].bytes = strlen(value); 75 } 76 77 return 0; 78 } 79 80 static int brcm_nvram_parse(struct brcm_nvram *priv) 81 { 82 struct device *dev = priv->dev; 83 struct brcm_nvram_header header; 84 uint8_t *data; 85 size_t len; 86 int err; 87 88 memcpy_fromio(&header, priv->base, sizeof(header)); 89 90 if (memcmp(header.magic, NVRAM_MAGIC, 4)) { 91 dev_err(dev, "Invalid NVRAM magic\n"); 92 return -EINVAL; 93 } 94 95 len = le32_to_cpu(header.len); 96 97 data = kcalloc(1, len, GFP_KERNEL); 98 memcpy_fromio(data, priv->base, len); 99 data[len - 1] = '\0'; 100 101 err = brcm_nvram_add_cells(priv, data, len); 102 if (err) { 103 dev_err(dev, "Failed to add cells: %d\n", err); 104 return err; 105 } 106 107 kfree(data); 108 109 return 0; 110 } 111 112 static int brcm_nvram_probe(struct platform_device *pdev) 113 { 114 struct nvmem_config config = { 115 .name = "brcm-nvram", 116 .reg_read = brcm_nvram_read, 117 }; 118 struct device *dev = &pdev->dev; 119 struct resource *res; 120 struct brcm_nvram *priv; 121 int err; 122 123 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 124 if (!priv) 125 return -ENOMEM; 126 priv->dev = dev; 127 128 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 129 priv->base = devm_ioremap_resource(dev, res); 130 if (IS_ERR(priv->base)) 131 return PTR_ERR(priv->base); 132 133 err = brcm_nvram_parse(priv); 134 if (err) 135 return err; 136 137 config.dev = dev; 138 config.cells = priv->cells; 139 config.ncells = priv->ncells; 140 config.priv = priv; 141 config.size = resource_size(res); 142 143 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config)); 144 } 145 146 static const struct of_device_id brcm_nvram_of_match_table[] = { 147 { .compatible = "brcm,nvram", }, 148 {}, 149 }; 150 151 static struct platform_driver brcm_nvram_driver = { 152 .probe = brcm_nvram_probe, 153 .driver = { 154 .name = "brcm_nvram", 155 .of_match_table = brcm_nvram_of_match_table, 156 }, 157 }; 158 159 static int __init brcm_nvram_init(void) 160 { 161 return platform_driver_register(&brcm_nvram_driver); 162 } 163 164 subsys_initcall_sync(brcm_nvram_init); 165 166 MODULE_AUTHOR("Rafał Miłecki"); 167 MODULE_LICENSE("GPL"); 168 MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table); 169