drivers: nvmem: add nvmem-huk driver

This driver is meant to read the otp unique hardware key from a
nvmem controller. It uses the nvmem framework to read the nvmem
cells from the device-tree.

Signed-off-by: Thomas Perrot <[email protected]>

core/drivers/nvmem/nvmem_huk.c

@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright (c) 2023, Microchip
+ */
+
+#include <drivers/nvmem.h>
+#include <io.h>
+#include <kernel/dt.h>
+#include <kernel/huk_subkey.h>
+#include <kernel/tee_common_otp.h>
+#include <malloc.h>
+#include <matrix.h>
+#include <sama5d2.h>
+#include <tee_api_defines.h>
+#include <tee_api_types.h>
+#include <types_ext.h>
+#include <trace.h>
+
+static uint8_t *huk;
+
+TEE_Result tee_otp_get_hw_unique_key(struct tee_hw_unique_key *hwkey)
+{
+	if (!huk)
+		return TEE_ERROR_NO_DATA;
+
+	memcpy(hwkey->data, huk, HW_UNIQUE_KEY_LENGTH);
+
+	return TEE_SUCCESS;
+}
+
+static TEE_Result nvmem_huk_read(const void *fdt, int node)
+{
+	TEE_Result res = TEE_ERROR_GENERIC;
+	struct nvmem_cell *cell = NULL;
+	uint8_t *data = NULL;
+	size_t len = 0;
+
+	res = nvmem_get_cell_by_name(fdt, node, "hw_unique_key", &cell);
+	if (res)
+		return res;
+
+	res = nvmem_cell_malloc_and_read(cell, &data);
+	if (res)
+		goto out_free_cell;
+
+	if (len != HW_UNIQUE_KEY_LENGTH) {
+		res = TEE_ERROR_GENERIC;
+		goto out_free_cell;
+	}
+	huk = data;
+
+out_free_cell:
+	nvmem_put_cell(cell);
+
+	return res;
+}
+
+static TEE_Result nvmem_huk_probe(const void *fdt, int node,
+				  const void *compat_data __unused)
+{
+	return nvmem_huk_read(fdt, node);
+}
+
+static const struct dt_device_match nvmem_huk_match_table[] = {
+	{ .compatible = "optee,nvmem-huk" },
+	{ }
+};
+
+DEFINE_DT_DRIVER(nvmem_huk_dt_driver) = {
+	.name = "nvmem_huk",
+	.type = DT_DRIVER_NVMEM,
+	.match_table = nvmem_huk_match_table,
+	.probe = nvmem_huk_probe,
+};

core/drivers/nvmem/sub.mk

@@ -1,3 +1,4 @@
 srcs-y += nvmem.c
 srcs-$(CFG_ATMEL_SFC) += atmel_sfc.c
 srcs-$(CFG_NVMEM_DIE_ID) += nvmem_die_id.c
+srcs-$(CFG_NVMEM_HUK) += nvmem_huk.c