diff --git a/include/services/oem/chromeos/widevine_smc_handlers.h b/include/services/oem/chromeos/widevine_smc_handlers.h
new file mode 100644
index 0000000..a5251d7
--- /dev/null
+++ b/include/services/oem/chromeos/widevine_smc_handlers.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2024, The ChromiumOS Authors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef CROS_WIDEVINE_SMC_HANDLERS_H
+#define CROS_WIDEVINE_SMC_HANDLERS_H
+
+#include <lib/smccc.h>
+
+/*******************************************************************************
+ * Defines for CrOS OEM Service queries
+ ******************************************************************************/
+
+/* 0xC300C050 - 0xC300C05F are CrOS OEM service calls */
+#define CROS_OEM_SMC_ID 0xC050
+#define CROS_OEM_SMC_CALL_ID(func_num)                                         \
+	((SMC_TYPE_FAST << FUNCID_TYPE_SHIFT) |                                \
+	 ((SMC_64) << FUNCID_CC_SHIFT) | (OEN_OEM_START << FUNCID_OEN_SHIFT) | \
+	 (CROS_OEM_SMC_ID) | ((func_num) & FUNCID_NUM_MASK))
+
+enum cros_drm_set {
+	CROS_DRM_SET_TPM_AUTH_PUB = 0U,
+	CROS_DRM_SET_HARDWARE_UNIQUE_KEY = 1U,
+	CROS_DRM_SET_ROOT_OF_TRUST = 2U,
+};
+
+/*******************************************************************************
+ * Defines for runtime services func ids
+ ******************************************************************************/
+
+/* Sets the TPM auth public key. The maximum size is 128 bytes.
+ * |x1| is the length of the data, |x2| is the physical address of the data.
+ */
+#define CROS_OEM_SMC_DRM_SET_TPM_AUTH_PUB_FUNC_ID \
+	CROS_OEM_SMC_CALL_ID(CROS_DRM_SET_TPM_AUTH_PUB)
+
+/* Sets the hardware unique key. The maximum size is 32 bytes.
+ * |x1| is the length of the data, |x2| is the physical address of the data.
+ */
+#define CROS_OEM_SMC_DRM_SET_HARDWARE_UNIQUE_KEY_FUNC_ID \
+	CROS_OEM_SMC_CALL_ID(CROS_DRM_SET_HARDWARE_UNIQUE_KEY)
+
+/* Sets the widevine root of trust. The maximum size is 32 bytes.
+ * |x1| is the length of the data, |x2| is the physical address of the data.
+ */
+#define CROS_OEM_SMC_DRM_SET_ROOT_OF_TRUST_FUNC_ID \
+	CROS_OEM_SMC_CALL_ID(CROS_DRM_SET_ROOT_OF_TRUST)
+
+#define is_cros_oem_smc(_call_id) (((_call_id) & 0xFFF0U) == CROS_OEM_SMC_ID)
+
+struct cros_oem_data {
+	uint8_t *buffer;
+	const uint32_t max_length;
+	uint32_t length;
+};
+
+extern struct cros_oem_data cros_oem_tpm_auth_pk;
+
+extern struct cros_oem_data cros_oem_huk;
+
+extern struct cros_oem_data cros_oem_rot;
+
+#endif /* CROS_WIDEVINE_SMC_HANDLERS_H */