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1// SPDX-License-Identifier: GPL-2.02 3#include <linux/crc8.h>4#include <linux/etherdevice.h>5#include <linux/nvmem-consumer.h>6#include <linux/nvmem-provider.h>7#include <linux/of.h>8#include <uapi/linux/if_ether.h>9 10#define SL28VPD_MAGIC 'V'11 12struct sl28vpd_header {13 u8 magic;14 u8 version;15} __packed;16 17struct sl28vpd_v1 {18 struct sl28vpd_header header;19 char serial_number[15];20 u8 base_mac_address[ETH_ALEN];21 u8 crc8;22} __packed;23 24static int sl28vpd_mac_address_pp(void *priv, const char *id, int index,25 unsigned int offset, void *buf,26 size_t bytes)27{28 if (bytes != ETH_ALEN)29 return -EINVAL;30 31 if (index < 0)32 return -EINVAL;33 34 if (!is_valid_ether_addr(buf))35 return -EINVAL;36 37 eth_addr_add(buf, index);38 39 return 0;40}41 42static const struct nvmem_cell_info sl28vpd_v1_entries[] = {43 {44 .name = "serial-number",45 .offset = offsetof(struct sl28vpd_v1, serial_number),46 .bytes = sizeof_field(struct sl28vpd_v1, serial_number),47 },48 {49 .name = "base-mac-address",50 .offset = offsetof(struct sl28vpd_v1, base_mac_address),51 .bytes = sizeof_field(struct sl28vpd_v1, base_mac_address),52 .read_post_process = sl28vpd_mac_address_pp,53 },54};55 56static int sl28vpd_v1_check_crc(struct device *dev, struct nvmem_device *nvmem)57{58 struct sl28vpd_v1 data_v1;59 u8 table[CRC8_TABLE_SIZE];60 int ret;61 u8 crc;62 63 crc8_populate_msb(table, 0x07);64 65 ret = nvmem_device_read(nvmem, 0, sizeof(data_v1), &data_v1);66 if (ret < 0)67 return ret;68 else if (ret != sizeof(data_v1))69 return -EIO;70 71 crc = crc8(table, (void *)&data_v1, sizeof(data_v1) - 1, 0);72 73 if (crc != data_v1.crc8) {74 dev_err(dev,75 "Checksum is invalid (got %02x, expected %02x).\n",76 crc, data_v1.crc8);77 return -EINVAL;78 }79 80 return 0;81}82 83static int sl28vpd_add_cells(struct nvmem_layout *layout)84{85 struct nvmem_device *nvmem = layout->nvmem;86 struct device *dev = &layout->dev;87 const struct nvmem_cell_info *pinfo;88 struct nvmem_cell_info info = {0};89 struct device_node *layout_np;90 struct sl28vpd_header hdr;91 int ret, i;92 93 /* check header */94 ret = nvmem_device_read(nvmem, 0, sizeof(hdr), &hdr);95 if (ret < 0)96 return ret;97 else if (ret != sizeof(hdr))98 return -EIO;99 100 if (hdr.magic != SL28VPD_MAGIC) {101 dev_err(dev, "Invalid magic value (%02x)\n", hdr.magic);102 return -EINVAL;103 }104 105 if (hdr.version != 1) {106 dev_err(dev, "Version %d is unsupported.\n", hdr.version);107 return -EINVAL;108 }109 110 ret = sl28vpd_v1_check_crc(dev, nvmem);111 if (ret)112 return ret;113 114 layout_np = of_nvmem_layout_get_container(nvmem);115 if (!layout_np)116 return -ENOENT;117 118 for (i = 0; i < ARRAY_SIZE(sl28vpd_v1_entries); i++) {119 pinfo = &sl28vpd_v1_entries[i];120 121 info.name = pinfo->name;122 info.offset = pinfo->offset;123 info.bytes = pinfo->bytes;124 info.read_post_process = pinfo->read_post_process;125 info.np = of_get_child_by_name(layout_np, pinfo->name);126 127 ret = nvmem_add_one_cell(nvmem, &info);128 if (ret) {129 of_node_put(layout_np);130 return ret;131 }132 }133 134 of_node_put(layout_np);135 136 return 0;137}138 139static int sl28vpd_probe(struct nvmem_layout *layout)140{141 layout->add_cells = sl28vpd_add_cells;142 143 return nvmem_layout_register(layout);144}145 146static void sl28vpd_remove(struct nvmem_layout *layout)147{148 nvmem_layout_unregister(layout);149}150 151static const struct of_device_id sl28vpd_of_match_table[] = {152 { .compatible = "kontron,sl28-vpd" },153 {},154};155MODULE_DEVICE_TABLE(of, sl28vpd_of_match_table);156 157static struct nvmem_layout_driver sl28vpd_layout = {158 .driver = {159 .name = "kontron-sl28vpd-layout",160 .of_match_table = sl28vpd_of_match_table,161 },162 .probe = sl28vpd_probe,163 .remove = sl28vpd_remove,164};165module_nvmem_layout_driver(sl28vpd_layout);166 167MODULE_LICENSE("GPL");168MODULE_AUTHOR("Michael Walle <michael@walle.cc>");169MODULE_DESCRIPTION("NVMEM layout driver for the VPD of Kontron sl28 boards");170