ONIE is a small operating system, pre-installed on bare metal network
switches, that provides an environment for automated provisioning.

This system requires that NVMEM (EEPROM) device holds various system
information (mac address, platform name, etc) in a special TLV layout.

The driver registers ONIE TLV attributes as NVMEM cells which can be
accessed by other platform driver. Also it allows to use
of_get_mac_address() to retrieve mac address for the netdev.

Signed-off-by: Vadym Kochan <vadym.koc...@plvision.eu>
---
 drivers/nvmem/Kconfig      |   9 +
 drivers/nvmem/Makefile     |   3 +
 drivers/nvmem/onie-cells.c | 332 +++++++++++++++++++++++++++++++++++++
 3 files changed, 344 insertions(+)
 create mode 100644 drivers/nvmem/onie-cells.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index d7b7f6d688e7..dd9298487992 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -273,4 +273,13 @@ config SPRD_EFUSE
          This driver can also be built as a module. If so, the module
          will be called nvmem-sprd-efuse.
 
+config NVMEM_ONIE_CELLS
+       tristate "ONIE TLV cells support"
+       help
+         This is a driver to provide cells from ONIE TLV structure stored
+         on NVME device.
+
+         This driver can also be built as a module. If so, the module
+         will be called nvmem-onie-cells.
+
 endif
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index a7c377218341..2199784a489f 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -55,3 +55,6 @@ obj-$(CONFIG_NVMEM_ZYNQMP)    += nvmem_zynqmp_nvmem.o
 nvmem_zynqmp_nvmem-y           := zynqmp_nvmem.o
 obj-$(CONFIG_SPRD_EFUSE)       += nvmem_sprd_efuse.o
 nvmem_sprd_efuse-y             := sprd-efuse.o
+
+obj-$(CONFIG_NVMEM_ONIE_CELLS) += nvmem-onie-cells.o
+nvmem-onie-cells-y             := onie-cells.o
diff --git a/drivers/nvmem/onie-cells.c b/drivers/nvmem/onie-cells.c
new file mode 100644
index 000000000000..1e8b4b8d1c0d
--- /dev/null
+++ b/drivers/nvmem/onie-cells.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ONIE NVMEM cells provider
+ *
+ * Author: Vadym Kochan <vadym.koc...@plvision.eu>
+ */
+
+#define ONIE_NVMEM_DRVNAME     "onie-nvmem-cells"
+
+#define pr_fmt(fmt) ONIE_NVMEM_DRVNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/nvmem-provider.h>
+
+#define ONIE_NVMEM_TLV_MAX_LEN 2048
+
+#define ONIE_NVMEM_HDR_ID      "TlvInfo"
+
+struct onie_nvmem_hdr {
+       u8 id[8];
+       u8 version;
+       __be16 data_len;
+} __packed;
+
+struct onie_nvmem_tlv {
+       u8 type;
+       u8 len;
+       u8 val[0];
+} __packed;
+
+struct onie_nvmem_attr {
+       struct list_head head;
+       const char *name;
+       unsigned int offset;
+       unsigned int len;
+};
+
+struct onie_nvmem {
+       struct nvmem_device *nvmem;
+       unsigned int attr_count;
+       struct list_head attrs;
+
+       struct nvmem_cell_lookup *cell_lookup;
+       struct nvmem_cell_table cell_tbl;
+};
+
+static bool onie_nvmem_hdr_is_valid(struct onie_nvmem_hdr *hdr)
+{
+       if (memcmp(hdr->id, ONIE_NVMEM_HDR_ID, sizeof(hdr->id)) != 0)
+               return false;
+       if (hdr->version != 0x1)
+               return false;
+
+       return true;
+}
+
+static void onie_nvmem_attrs_free(struct onie_nvmem *onie)
+{
+       struct onie_nvmem_attr *attr, *tmp;
+
+       list_for_each_entry_safe(attr, tmp, &onie->attrs, head) {
+               list_del(&attr->head);
+               kfree(attr);
+       }
+}
+
+static const char *onie_nvmem_attr_name(u8 type)
+{
+       switch (type) {
+       case 0x21: return "product-name";
+       case 0x22: return "part-number";
+       case 0x23: return "serial-number";
+       case 0x24: return "mac-address";
+       case 0x25: return "manufacture-date";
+       case 0x26: return "device-version";
+       case 0x27: return "label-revision";
+       case 0x28: return "platforn-name";
+       case 0x29: return "onie-version";
+       case 0x2A: return "num-macs";
+       case 0x2B: return "manufacturer";
+       case 0x2C: return "country-code";
+       case 0x2D: return "vendor";
+       case 0x2E: return "diag-version";
+       case 0x2F: return "service-tag";
+       case 0xFD: return "vendor-extension";
+       case 0xFE: return "crc32";
+
+       default: return "unknown";
+       }
+}
+
+static int onie_nvmem_tlv_parse(struct onie_nvmem *onie, u8 *data, u16 len)
+{
+       unsigned int hlen = sizeof(struct onie_nvmem_hdr);
+       unsigned int offset = 0;
+       int err;
+
+       while (offset < len) {
+               struct onie_nvmem_attr *attr;
+               struct onie_nvmem_tlv *tlv;
+
+               tlv = (struct onie_nvmem_tlv *)(data + offset);
+
+               if (offset + tlv->len >= len) {
+                       struct nvmem_device *nvmem = onie->nvmem;
+
+                       pr_err("%s: TLV len is too big(0x%x) at 0x%x\n",
+                              nvmem_dev_name(nvmem), tlv->len, hlen + offset);
+
+                       /* return success in case something was parsed */
+                       return 0;
+               }
+
+               attr = kmalloc(sizeof(*attr), GFP_KERNEL);
+               if (!attr) {
+                       err = -ENOMEM;
+                       goto err_attr_alloc;
+               }
+
+               attr->name = onie_nvmem_attr_name(tlv->type);
+               /* skip 'type' and 'len' */
+               attr->offset = hlen + offset + 2;
+               attr->len = tlv->len;
+
+               list_add(&attr->head, &onie->attrs);
+               onie->attr_count++;
+
+               offset += sizeof(*tlv) + tlv->len;
+       }
+
+       return 0;
+
+err_attr_alloc:
+       onie_nvmem_attrs_free(onie);
+
+       return err;
+}
+
+static int onie_nvmem_decode(struct onie_nvmem *onie)
+{
+       struct nvmem_device *nvmem = onie->nvmem;
+       struct onie_nvmem_hdr hdr;
+       u8 *data;
+       u16 len;
+       int ret;
+
+       ret = nvmem_device_read(nvmem, 0, sizeof(hdr), &hdr);
+       if (ret < 0)
+               return ret;
+
+       if (!onie_nvmem_hdr_is_valid(&hdr)) {
+               pr_err("%s: invalid ONIE TLV header\n", nvmem_dev_name(nvmem));
+               ret = -EINVAL;
+               goto err_invalid;
+       }
+
+       len = be16_to_cpu(hdr.data_len);
+
+       if (len > ONIE_NVMEM_TLV_MAX_LEN)
+               len = ONIE_NVMEM_TLV_MAX_LEN;
+
+       data = kmalloc(len, GFP_KERNEL);
+       if (!data) {
+               ret = -ENOMEM;
+               goto err_kmalloc;
+       }
+
+       ret = nvmem_device_read(nvmem, sizeof(hdr), len, data);
+       if (ret < 0)
+               goto err_data_read;
+
+       ret = onie_nvmem_tlv_parse(onie, data, len);
+       if (ret)
+               goto err_info_parse;
+
+       kfree(data);
+
+       return 0;
+
+err_info_parse:
+err_data_read:
+       kfree(data);
+err_kmalloc:
+err_invalid:
+       return ret;
+}
+
+static int onie_nvmem_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device_node *np = dev->of_node;
+       struct nvmem_cell_info *cells;
+       struct onie_nvmem_attr *attr;
+       struct nvmem_device *nvmem;
+       struct onie_nvmem *onie;
+       unsigned int ncells = 0;
+       int err;
+
+       nvmem = of_nvmem_device_get(np, NULL);
+       if (IS_ERR(nvmem))
+               return PTR_ERR(nvmem);
+
+       onie = kmalloc(sizeof(*onie), GFP_KERNEL);
+       if (!onie) {
+               err = -ENOMEM;
+               goto err_nvmem_alloc;
+       }
+
+       INIT_LIST_HEAD(&onie->attrs);
+       onie->attr_count = 0;
+       onie->nvmem = nvmem;
+
+       err = onie_nvmem_decode(onie);
+       if (err)
+               goto err_nvmem_decode;
+
+       if (!onie->attr_count) {
+               pr_err("%s: has no ONIE attributes\n", nvmem_dev_name(nvmem));
+               err = -EINVAL;
+               goto err_no_attrs;
+       }
+
+       cells = kmalloc_array(onie->attr_count, sizeof(*cells), GFP_KERNEL);
+       if (!cells) {
+               err = -ENOMEM;
+               goto err_cells_alloc;
+       }
+
+       onie->cell_lookup = kmalloc_array(onie->attr_count,
+                                         sizeof(struct nvmem_cell_lookup),
+                                         GFP_KERNEL);
+       if (!onie->cell_lookup) {
+               err = -ENOMEM;
+               goto err_lookup_alloc;
+       }
+
+       list_for_each_entry(attr, &onie->attrs, head) {
+               struct nvmem_cell_lookup *lookup;
+               struct nvmem_cell_info *cell;
+
+               cell = &cells[ncells];
+
+               lookup = &onie->cell_lookup[ncells];
+               lookup->con_id = NULL;
+
+               cell->offset = attr->offset;
+               cell->name = attr->name;
+               cell->bytes = attr->len;
+               cell->bit_offset = 0;
+               cell->nbits = 0;
+
+               lookup->nvmem_name = nvmem_dev_name(onie->nvmem);
+               lookup->dev_id = dev_name(dev);
+               lookup->cell_name = cell->name;
+               lookup->con_id = cell->name;
+
+               ncells++;
+       }
+
+       onie->cell_tbl.nvmem_name = nvmem_dev_name(onie->nvmem);
+       onie->cell_tbl.ncells = ncells;
+       onie->cell_tbl.cells = cells;
+
+       nvmem_add_cell_table(&onie->cell_tbl);
+       nvmem_add_cell_lookups(onie->cell_lookup, ncells);
+
+       dev_set_drvdata(dev, onie);
+
+       onie_nvmem_attrs_free(onie);
+
+       nvmem_device_put(nvmem);
+
+       return 0;
+
+err_lookup_alloc:
+       kfree(onie->cell_tbl.cells);
+err_cells_alloc:
+       onie_nvmem_attrs_free(onie);
+err_no_attrs:
+err_nvmem_decode:
+       kfree(onie);
+err_nvmem_alloc:
+       nvmem_device_put(nvmem);
+
+       return err;
+}
+
+static int onie_nvmem_remove(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct onie_nvmem *onie;
+
+       onie = dev_get_drvdata(dev);
+
+       nvmem_del_cell_lookups(onie->cell_lookup, onie->attr_count);
+       nvmem_del_cell_table(&onie->cell_tbl);
+
+       kfree(onie->cell_tbl.cells);
+       kfree(onie->cell_lookup);
+       kfree(onie);
+
+       return 0;
+}
+
+static const struct of_device_id onie_nvmem_match[] = {
+       {
+               .compatible = "onie-nvmem-cells",
+       },
+       { }
+};
+MODULE_DEVICE_TABLE(of, onie_nvmem_match);
+
+static struct platform_driver onie_nvmem_driver = {
+       .probe = onie_nvmem_probe,
+       .remove = onie_nvmem_remove,
+       .driver = {
+               .name = ONIE_NVMEM_DRVNAME,
+               .of_match_table = onie_nvmem_match,
+       },
+};
+module_platform_driver(onie_nvmem_driver);
+
+MODULE_AUTHOR("Vadym Kochan <vadym.koc...@plvision.eu>");
+MODULE_DESCRIPTION("ONIE NVMEM cells driver");
+MODULE_LICENSE("GPL");
-- 
2.17.1

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