target/linux/generic/backport-5.15/811-v6.4-0010-nvmem-layouts-sl28vpd-Add-new-layout-driver.patch

   1 From d9fae023fe86069750092fc1c2f3a73e2fb18512 Mon Sep 17 00:00:00 2001
   2 From: Michael Walle <michael@walle.cc>
   3 Date: Tue, 4 Apr 2023 18:21:29 +0100
   4 Subject: [PATCH] nvmem: layouts: sl28vpd: Add new layout driver
   5
   6 This layout applies to the VPD of the Kontron sl28 boards. The VPD only
   7 contains a base MAC address. Therefore, we have to add an individual
   8 offset to it. This is done by taking the second argument of the nvmem
   9 phandle into account. Also this let us checking the VPD version and the
  10 checksum.
  11
  12 Signed-off-by: Michael Walle <michael@walle.cc>
  13 Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
  14 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  15 Link: https://lore.kernel.org/r/20230404172148.82422-22-srinivas.kandagatla@linaro.org
  16 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  17 ---
  18  drivers/nvmem/layouts/Kconfig   |   9 ++
  19  drivers/nvmem/layouts/Makefile  |   2 +
  20  drivers/nvmem/layouts/sl28vpd.c | 165 ++++++++++++++++++++++++++++++++
  21  3 files changed, 176 insertions(+)
  22  create mode 100644 drivers/nvmem/layouts/sl28vpd.c
  23
  24 --- a/drivers/nvmem/layouts/Kconfig
  25 +++ b/drivers/nvmem/layouts/Kconfig
  26 @@ -2,4 +2,13 @@
  27
  28  menu "Layout Types"
  29
  30 +config NVMEM_LAYOUT_SL28_VPD
  31 +       tristate "Kontron sl28 VPD layout support"
  32 +       select CRC8
  33 +       help
  34 +         Say Y here if you want to support the VPD layout of the Kontron
  35 +         SMARC-sAL28 boards.
  36 +
  37 +         If unsure, say N.
  38 +
  39  endmenu
  40 --- a/drivers/nvmem/layouts/Makefile
  41 +++ b/drivers/nvmem/layouts/Makefile
  42 @@ -2,3 +2,5 @@
  43  #
  44  # Makefile for nvmem layouts.
  45  #
  46 +
  47 +obj-$(CONFIG_NVMEM_LAYOUT_SL28_VPD) += sl28vpd.o
  48 --- /dev/null
  49 +++ b/drivers/nvmem/layouts/sl28vpd.c
  50 @@ -0,0 +1,165 @@
  51 +// SPDX-License-Identifier: GPL-2.0
  52 +
  53 +#include <linux/crc8.h>
  54 +#include <linux/etherdevice.h>
  55 +#include <linux/nvmem-consumer.h>
  56 +#include <linux/nvmem-provider.h>
  57 +#include <linux/of.h>
  58 +#include <uapi/linux/if_ether.h>
  59 +
  60 +#define SL28VPD_MAGIC 'V'
  61 +
  62 +struct sl28vpd_header {
  63 +       u8 magic;
  64 +       u8 version;
  65 +} __packed;
  66 +
  67 +struct sl28vpd_v1 {
  68 +       struct sl28vpd_header header;
  69 +       char serial_number[15];
  70 +       u8 base_mac_address[ETH_ALEN];
  71 +       u8 crc8;
  72 +} __packed;
  73 +
  74 +static int sl28vpd_mac_address_pp(void *priv, const char *id, int index,
  75 +                                 unsigned int offset, void *buf,
  76 +                                 size_t bytes)
  77 +{
  78 +       if (bytes != ETH_ALEN)
  79 +               return -EINVAL;
  80 +
  81 +       if (index < 0)
  82 +               return -EINVAL;
  83 +
  84 +       if (!is_valid_ether_addr(buf))
  85 +               return -EINVAL;
  86 +
  87 +       eth_addr_add(buf, index);
  88 +
  89 +       return 0;
  90 +}
  91 +
  92 +static const struct nvmem_cell_info sl28vpd_v1_entries[] = {
  93 +       {
  94 +               .name = "serial-number",
  95 +               .offset = offsetof(struct sl28vpd_v1, serial_number),
  96 +               .bytes = sizeof_field(struct sl28vpd_v1, serial_number),
  97 +       },
  98 +       {
  99 +               .name = "base-mac-address",
 100 +               .offset = offsetof(struct sl28vpd_v1, base_mac_address),
 101 +               .bytes = sizeof_field(struct sl28vpd_v1, base_mac_address),
 102 +               .read_post_process = sl28vpd_mac_address_pp,
 103 +       },
 104 +};
 105 +
 106 +static int sl28vpd_v1_check_crc(struct device *dev, struct nvmem_device *nvmem)
 107 +{
 108 +       struct sl28vpd_v1 data_v1;
 109 +       u8 table[CRC8_TABLE_SIZE];
 110 +       int ret;
 111 +       u8 crc;
 112 +
 113 +       crc8_populate_msb(table, 0x07);
 114 +
 115 +       ret = nvmem_device_read(nvmem, 0, sizeof(data_v1), &data_v1);
 116 +       if (ret < 0)
 117 +               return ret;
 118 +       else if (ret != sizeof(data_v1))
 119 +               return -EIO;
 120 +
 121 +       crc = crc8(table, (void *)&data_v1, sizeof(data_v1) - 1, 0);
 122 +
 123 +       if (crc != data_v1.crc8) {
 124 +               dev_err(dev,
 125 +                       "Checksum is invalid (got %02x, expected %02x).\n",
 126 +                       crc, data_v1.crc8);
 127 +               return -EINVAL;
 128 +       }
 129 +
 130 +       return 0;
 131 +}
 132 +
 133 +static int sl28vpd_add_cells(struct device *dev, struct nvmem_device *nvmem,
 134 +                            struct nvmem_layout *layout)
 135 +{
 136 +       const struct nvmem_cell_info *pinfo;
 137 +       struct nvmem_cell_info info = {0};
 138 +       struct device_node *layout_np;
 139 +       struct sl28vpd_header hdr;
 140 +       int ret, i;
 141 +
 142 +       /* check header */
 143 +       ret = nvmem_device_read(nvmem, 0, sizeof(hdr), &hdr);
 144 +       if (ret < 0)
 145 +               return ret;
 146 +       else if (ret != sizeof(hdr))
 147 +               return -EIO;
 148 +
 149 +       if (hdr.magic != SL28VPD_MAGIC) {
 150 +               dev_err(dev, "Invalid magic value (%02x)\n", hdr.magic);
 151 +               return -EINVAL;
 152 +       }
 153 +
 154 +       if (hdr.version != 1) {
 155 +               dev_err(dev, "Version %d is unsupported.\n", hdr.version);
 156 +               return -EINVAL;
 157 +       }
 158 +
 159 +       ret = sl28vpd_v1_check_crc(dev, nvmem);
 160 +       if (ret)
 161 +               return ret;
 162 +
 163 +       layout_np = of_nvmem_layout_get_container(nvmem);
 164 +       if (!layout_np)
 165 +               return -ENOENT;
 166 +
 167 +       for (i = 0; i < ARRAY_SIZE(sl28vpd_v1_entries); i++) {
 168 +               pinfo = &sl28vpd_v1_entries[i];
 169 +
 170 +               info.name = pinfo->name;
 171 +               info.offset = pinfo->offset;
 172 +               info.bytes = pinfo->bytes;
 173 +               info.read_post_process = pinfo->read_post_process;
 174 +               info.np = of_get_child_by_name(layout_np, pinfo->name);
 175 +
 176 +               ret = nvmem_add_one_cell(nvmem, &info);
 177 +               if (ret) {
 178 +                       of_node_put(layout_np);
 179 +                       return ret;
 180 +               }
 181 +       }
 182 +
 183 +       of_node_put(layout_np);
 184 +
 185 +       return 0;
 186 +}
 187 +
 188 +static const struct of_device_id sl28vpd_of_match_table[] = {
 189 +       { .compatible = "kontron,sl28-vpd" },
 190 +       {},
 191 +};
 192 +MODULE_DEVICE_TABLE(of, sl28vpd_of_match_table);
 193 +
 194 +struct nvmem_layout sl28vpd_layout = {
 195 +       .name = "sl28-vpd",
 196 +       .of_match_table = sl28vpd_of_match_table,
 197 +       .add_cells = sl28vpd_add_cells,
 198 +};
 199 +
 200 +static int __init sl28vpd_init(void)
 201 +{
 202 +       return nvmem_layout_register(&sl28vpd_layout);
 203 +}
 204 +
 205 +static void __exit sl28vpd_exit(void)
 206 +{
 207 +       nvmem_layout_unregister(&sl28vpd_layout);
 208 +}
 209 +
 210 +module_init(sl28vpd_init);
 211 +module_exit(sl28vpd_exit);
 212 +
 213 +MODULE_LICENSE("GPL");
 214 +MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
 215 +MODULE_DESCRIPTION("NVMEM layout driver for the VPD of Kontron sl28 boards");