nvmem: layouts: sl28vpd: Add new layout driver

This layout applies to the VPD of the Kontron sl28 boards. The VPD only
contains a base MAC address. Therefore, we have to add an individual
offset to it. This is done by taking the second argument of the nvmem
phandle into account. Also this let us checking the VPD version and the
checksum.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-22-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig
index 9ad3911d160531ac0c4bc51e03dfdac6e23e7c85..fd161347c12952a0a0d4b94d50461c8db2d66efc 100644 (file)
--- a/drivers/nvmem/layouts/Kconfig
+++ b/drivers/nvmem/layouts/Kconfig
@@ -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

diff --git a/drivers/nvmem/layouts/Makefile b/drivers/nvmem/layouts/Makefile
index 6fdb3c60a4fa0088da50d0ef7495dd820b96619d..fc617b9e87d0efcd51f917daa5e531d10197f5fe 100644 (file)
--- a/drivers/nvmem/layouts/Makefile
+++ b/drivers/nvmem/layouts/Makefile
@@ -2,3 +2,5 @@
 #
 # Makefile for nvmem layouts.
 #
+
+obj-$(CONFIG_NVMEM_LAYOUT_SL28_VPD) += sl28vpd.o

diff --git a/drivers/nvmem/layouts/sl28vpd.c b/drivers/nvmem/layouts/sl28vpd.c
new file mode 100644 (file)
index 0000000..9370e41
--- /dev/null
+++ b/drivers/nvmem/layouts/sl28vpd.c
@@ -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");