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