@@ -2,4 +2,13 @@
menu "Layout Types"
+config NVMEM_LAYOUT_SL28_VPD
+ tristate "Kontron sl28 VPD layout support"
+ select CRC8
+ help
+ Say Y here if you want to support the VPD layout of the Kontron
+ SMARC-sAL28 boards.
+
+ If unsure, say N.
+
endmenu
@@ -2,3 +2,5 @@
#
# Makefile for nvmem layouts.
#
+
+obj-$(CONFIG_NVMEM_LAYOUT_SL28_VPD) += sl28vpd.o
new file mode 100644
@@ -0,0 +1,165 @@
+// 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);
+
+struct nvmem_layout sl28vpd_layout = {
+ .name = "sl28-vpd",
+ .of_match_table = sl28vpd_of_match_table,
+ .add_cells = sl28vpd_add_cells,
+};
+
+static int __init sl28vpd_init(void)
+{
+ return nvmem_layout_register(&sl28vpd_layout);
+}
+
+static void __exit sl28vpd_exit(void)
+{
+ nvmem_layout_unregister(&sl28vpd_layout);
+}
+
+module_init(sl28vpd_init);
+module_exit(sl28vpd_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
+MODULE_DESCRIPTION("NVMEM layout driver for the VPD of Kontron sl28 boards");