+
+/**
+ * tpm2_probe() - probe TPM 2.0
+ * @chip: TPM chip to use
+ *
+ * Send idempotent TPM 2.0 command and see whether TPM 2.0 chip replied based on
+ * the reply tag.
+ */
+int tpm2_probe(struct tpm_chip *chip)
+{
+ struct tpm2_cmd cmd;
+ int rc;
+
+ cmd.header.in = tpm2_get_tpm_pt_header;
+ cmd.params.get_tpm_pt_in.cap_id = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES);
+ cmd.params.get_tpm_pt_in.property_id = cpu_to_be32(0x100);
+ cmd.params.get_tpm_pt_in.property_cnt = cpu_to_be32(1);
+
+ rc = tpm_transmit(chip, (const char *) &cmd, sizeof(cmd));
+ if (rc < 0)
+ return rc;
+ else if (rc < TPM_HEADER_SIZE)
+ return -EFAULT;
+
+ if (be16_to_cpu(cmd.header.out.tag) == TPM2_ST_NO_SESSIONS)
+ chip->flags |= TPM_CHIP_FLAG_TPM2;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(tpm2_probe);