drivers/nvmem/brcm_nvram.c

   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 struct brcm_nvram {
  21         struct device *dev;
  22         void __iomem *base;
  23         struct nvmem_cell_info *cells;
  24         int ncells;
  25 };
  26
  27 struct brcm_nvram_header {
  28         char magic[4];
  29         __le32 len;
  30         __le32 crc_ver_init;    /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
  31         __le32 config_refresh;  /* 0:15 sdram_config, 16:31 sdram_refresh */
  32         __le32 config_ncdl;     /* ncdl values for memc */
  33 };
  34
  35 static int brcm_nvram_read(void *context, unsigned int offset, void *val,
  36                            size_t bytes)
  37 {
  38         struct brcm_nvram *priv = context;
  39         u8 *dst = val;
  40
  41         while (bytes--)
  42                 *dst++ = readb(priv->base + offset++);
  43
  44         return 0;
  45 }
  46
  47 static int brcm_nvram_read_post_process_macaddr(void *context, const char *id, int index,
  48                                                 unsigned int offset, void *buf, size_t bytes)
  49 {
  50         u8 mac[ETH_ALEN];
  51
  52         if (bytes != 3 * ETH_ALEN - 1)
  53                 return -EINVAL;
  54
  55         if (!mac_pton(buf, mac))
  56                 return -EINVAL;
  57
  58         if (index)
  59                 eth_addr_add(mac, index);
  60
  61         ether_addr_copy(buf, mac);
  62
  63         return 0;
  64 }
  65
  66 static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data,
  67                                 size_t len)
  68 {
  69         struct device *dev = priv->dev;
  70         char *var, *value, *eq;
  71         int idx;
  72
  73         priv->ncells = 0;
  74         for (var = data + sizeof(struct brcm_nvram_header);
  75              var < (char *)data + len && *var;
  76              var += strlen(var) + 1) {
  77                 priv->ncells++;
  78         }
  79
  80         priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
  81         if (!priv->cells)
  82                 return -ENOMEM;
  83
  84         for (var = data + sizeof(struct brcm_nvram_header), idx = 0;
  85              var < (char *)data + len && *var;
  86              var = value + strlen(value) + 1, idx++) {
  87                 eq = strchr(var, '=');
  88                 if (!eq)
  89                         break;
  90                 *eq = '\0';
  91                 value = eq + 1;
  92
  93                 priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
  94                 if (!priv->cells[idx].name)
  95                         return -ENOMEM;
  96                 priv->cells[idx].offset = value - (char *)data;
  97                 priv->cells[idx].bytes = strlen(value);
  98                 priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
  99                 if (!strcmp(var, "et0macaddr") ||
 100                     !strcmp(var, "et1macaddr") ||
 101                     !strcmp(var, "et2macaddr")) {
 102                         priv->cells[idx].raw_len = strlen(value);
 103                         priv->cells[idx].bytes = ETH_ALEN;
 104                         priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr;
 105                 }
 106         }
 107
 108         return 0;
 109 }
 110
 111 static int brcm_nvram_parse(struct brcm_nvram *priv)
 112 {
 113         struct device *dev = priv->dev;
 114         struct brcm_nvram_header header;
 115         uint8_t *data;
 116         size_t len;
 117         int err;
 118
 119         memcpy_fromio(&header, priv->base, sizeof(header));
 120
 121         if (memcmp(header.magic, NVRAM_MAGIC, 4)) {
 122                 dev_err(dev, "Invalid NVRAM magic\n");
 123                 return -EINVAL;
 124         }
 125
 126         len = le32_to_cpu(header.len);
 127
 128         data = kzalloc(len, GFP_KERNEL);
 129         if (!data)
 130                 return -ENOMEM;
 131
 132         memcpy_fromio(data, priv->base, len);
 133         data[len - 1] = '\0';
 134
 135         err = brcm_nvram_add_cells(priv, data, len);
 136         if (err) {
 137                 dev_err(dev, "Failed to add cells: %d\n", err);
 138                 return err;
 139         }
 140
 141         kfree(data);
 142
 143         return 0;
 144 }
 145
 146 static int brcm_nvram_probe(struct platform_device *pdev)
 147 {
 148         struct nvmem_config config = {
 149                 .name = "brcm-nvram",
 150                 .reg_read = brcm_nvram_read,
 151         };
 152         struct device *dev = &pdev->dev;
 153         struct resource *res;
 154         struct brcm_nvram *priv;
 155         int err;
 156
 157         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 158         if (!priv)
 159                 return -ENOMEM;
 160         priv->dev = dev;
 161
 162         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 163         priv->base = devm_ioremap_resource(dev, res);
 164         if (IS_ERR(priv->base))
 165                 return PTR_ERR(priv->base);
 166
 167         err = brcm_nvram_parse(priv);
 168         if (err)
 169                 return err;
 170
 171         bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res));
 172
 173         config.dev = dev;
 174         config.cells = priv->cells;
 175         config.ncells = priv->ncells;
 176         config.priv = priv;
 177         config.size = resource_size(res);
 178
 179         return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
 180 }
 181
 182 static const struct of_device_id brcm_nvram_of_match_table[] = {
 183         { .compatible = "brcm,nvram", },
 184         {},
 185 };
 186
 187 static struct platform_driver brcm_nvram_driver = {
 188         .probe = brcm_nvram_probe,
 189         .driver = {
 190                 .name = "brcm_nvram",
 191                 .of_match_table = brcm_nvram_of_match_table,
 192         },
 193 };
 194
 195 static int __init brcm_nvram_init(void)
 196 {
 197         return platform_driver_register(&brcm_nvram_driver);
 198 }
 199
 200 subsys_initcall_sync(brcm_nvram_init);
 201
 202 MODULE_AUTHOR("Rafał Miłecki");
 203 MODULE_LICENSE("GPL");
 204 MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);