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1// SPDX-License-Identifier: GPL-2.0-only2/*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 struct22 *23 * @dev: NVMEM device pointer24 * @nvmem_size: Size of the whole space available for NVRAM25 * @data: NVRAM data copy stored to avoid poking underlaying flash controller26 * @data_len: NVRAM data size27 * @padding_byte: Padding value used to fill remaining space28 * @cells: Array of discovered NVMEM cells29 * @ncells: Number of elements in cells30 */31struct 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 41struct 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 49static 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 else58 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 67static 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 98static 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 117static 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 172out:173 priv->data[len - 1] = tmp;174 return err;175}176 177static 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 203static 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 235static const struct of_device_id brcm_nvram_of_match_table[] = {236 { .compatible = "brcm,nvram", },237 {},238};239 240static 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 248static int __init brcm_nvram_init(void)249{250 return platform_driver_register(&brcm_nvram_driver);251}252 253subsys_initcall_sync(brcm_nvram_init);254 255MODULE_AUTHOR("Rafał Miłecki");256MODULE_DESCRIPTION("Broadcom I/O-mapped NVRAM support driver");257MODULE_LICENSE("GPL");258MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);259