1 // SPDX-License-Identifier: GPL-2.0 2 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 12 struct sl28vpd_header { 13 u8 magic; 14 u8 version; 15 } __packed; 16 17 struct 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 24 static 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 42 static 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 56 static 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 83 static 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 } 138 139 static int sl28vpd_probe(struct nvmem_layout *layout) 140 { 141 layout->add_cells = sl28vpd_add_cells; 142 143 return nvmem_layout_register(layout); 144 } 145 146 static void sl28vpd_remove(struct nvmem_layout *layout) 147 { 148 nvmem_layout_unregister(layout); 149 } 150 151 static const struct of_device_id sl28vpd_of_match_table[] = { 152 { .compatible = "kontron,sl28-vpd" }, 153 {}, 154 }; 155 MODULE_DEVICE_TABLE(of, sl28vpd_of_match_table); 156 157 static struct nvmem_layout_driver sl28vpd_layout = { 158 .driver = { 159 .owner = THIS_MODULE, 160 .name = "kontron-sl28vpd-layout", 161 .of_match_table = sl28vpd_of_match_table, 162 }, 163 .probe = sl28vpd_probe, 164 .remove = sl28vpd_remove, 165 }; 166 module_nvmem_layout_driver(sl28vpd_layout); 167 168 MODULE_LICENSE("GPL"); 169 MODULE_AUTHOR("Michael Walle <michael@walle.cc>"); 170 MODULE_DESCRIPTION("NVMEM layout driver for the VPD of Kontron sl28 boards"); 171