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// SPDX-License-Identifier: GPL-2.0
#include <linux/crc8.h>
#include <linux/etherdevice.h>
#include <linux/nvmem-consumer.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <uapi/linux/if_ether.h>
#define SL28VPD_MAGIC 'V'
struct sl28vpd_header {
u8 magic;
u8 version;
} __packed;
struct sl28vpd_v1 {
struct sl28vpd_header header;
char serial_number[15];
u8 base_mac_address[ETH_ALEN];
u8 crc8;
} __packed;
static int sl28vpd_mac_address_pp(void *priv, const char *id, int index,
unsigned int offset, void *buf,
size_t bytes)
{
if (bytes != ETH_ALEN)
return -EINVAL;
if (index < 0)
return -EINVAL;
if (!is_valid_ether_addr(buf))
return -EINVAL;
eth_addr_add(buf, index);
return 0;
}
static const struct nvmem_cell_info sl28vpd_v1_entries[] = {
{
.name = "serial-number",
.offset = offsetof(struct sl28vpd_v1, serial_number),
.bytes = sizeof_field(struct sl28vpd_v1, serial_number),
},
{
.name = "base-mac-address",
.offset = offsetof(struct sl28vpd_v1, base_mac_address),
.bytes = sizeof_field(struct sl28vpd_v1, base_mac_address),
.read_post_process = sl28vpd_mac_address_pp,
},
};
static int sl28vpd_v1_check_crc(struct device *dev, struct nvmem_device *nvmem)
{
struct sl28vpd_v1 data_v1;
u8 table[CRC8_TABLE_SIZE];
int ret;
u8 crc;
crc8_populate_msb(table, 0x07);
ret = nvmem_device_read(nvmem, 0, sizeof(data_v1), &data_v1);
if (ret < 0)
return ret;
else if (ret != sizeof(data_v1))
return -EIO;
crc = crc8(table, (void *)&data_v1, sizeof(data_v1) - 1, 0);
if (crc != data_v1.crc8) {
dev_err(dev,
"Checksum is invalid (got %02x, expected %02x).\n",
crc, data_v1.crc8);
return -EINVAL;
}
return 0;
}
static int sl28vpd_add_cells(struct device *dev, struct nvmem_device *nvmem,
struct nvmem_layout *layout)
{
const struct nvmem_cell_info *pinfo;
struct nvmem_cell_info info = {0};
struct device_node *layout_np;
struct sl28vpd_header hdr;
int ret, i;
/* check header */
ret = nvmem_device_read(nvmem, 0, sizeof(hdr), &hdr);
if (ret < 0)
return ret;
else if (ret != sizeof(hdr))
return -EIO;
if (hdr.magic != SL28VPD_MAGIC) {
dev_err(dev, "Invalid magic value (%02x)\n", hdr.magic);
return -EINVAL;
}
if (hdr.version != 1) {
dev_err(dev, "Version %d is unsupported.\n", hdr.version);
return -EINVAL;
}
ret = sl28vpd_v1_check_crc(dev, nvmem);
if (ret)
return ret;
layout_np = of_nvmem_layout_get_container(nvmem);
if (!layout_np)
return -ENOENT;
for (i = 0; i < ARRAY_SIZE(sl28vpd_v1_entries); i++) {
pinfo = &sl28vpd_v1_entries[i];
info.name = pinfo->name;
info.offset = pinfo->offset;
info.bytes = pinfo->bytes;
info.read_post_process = pinfo->read_post_process;
info.np = of_get_child_by_name(layout_np, pinfo->name);
ret = nvmem_add_one_cell(nvmem, &info);
if (ret) {
of_node_put(layout_np);
return ret;
}
}
of_node_put(layout_np);
return 0;
}
static const struct of_device_id sl28vpd_of_match_table[] = {
{ .compatible = "kontron,sl28-vpd" },
{},
};
MODULE_DEVICE_TABLE(of, sl28vpd_of_match_table);
static struct nvmem_layout sl28vpd_layout = {
.name = "sl28-vpd",
.of_match_table = sl28vpd_of_match_table,
.add_cells = sl28vpd_add_cells,
};
module_nvmem_layout_driver(sl28vpd_layout);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
MODULE_DESCRIPTION("NVMEM layout driver for the VPD of Kontron sl28 boards");
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