tpm, tpm_tis: fix TPM 2.0 probing

[cascardo/linux.git] / drivers / char / tpm / tpm2-cmd.c

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 1abe650..011909a 100644 (file)
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -456,20 +456,23 @@ static const struct tpm_input_header tpm2_shutdown_header = {
  * @chip:              TPM chip to use.
  * @shutdown_type      shutdown type. The value is either
  *                     TPM_SU_CLEAR or TPM_SU_STATE.
- *
- * 0 is returned when the operation is successful. If a negative number is
- * returned it remarks a POSIX error code. If a positive number is returned
- * it remarks a TPM error.
  */
-int tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
+void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
 {
        struct tpm2_cmd cmd;
+       int rc;
 
        cmd.header.in = tpm2_shutdown_header;
-
        cmd.params.startup_in.startup_type = cpu_to_be16(shutdown_type);
-       return tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
-                               "stopping the TPM");
+
+       rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), "stopping the TPM");
+
+       /* In places where shutdown command is sent there's no much we can do
+        * except print the error code on a system failure.
+        */
+       if (rc < 0)
+               dev_warn(chip->pdev, "transmit returned %d while stopping the TPM",
+                        rc);
 }
 EXPORT_SYMBOL_GPL(tpm2_shutdown);
 
@@ -598,20 +601,46 @@ EXPORT_SYMBOL_GPL(tpm2_do_selftest);
 /**
  * tpm2_gen_interrupt() - generate an interrupt
  * @chip: TPM chip to use
- * @quiet: surpress the error message
  *
  * 0 is returned when the operation is successful. If a negative number is
  * returned it remarks a POSIX error code. If a positive number is returned
  * it remarks a TPM error.
  */
-int tpm2_gen_interrupt(struct tpm_chip *chip, bool quiet)
+int tpm2_gen_interrupt(struct tpm_chip *chip)
 {
-       const char *desc = NULL;
        u32 dummy;
 
-       if (!quiet)
-               desc = "attempting to generate an interrupt";
-
-       return tpm2_get_tpm_pt(chip, TPM2_CAP_TPM_PROPERTIES, &dummy, desc);
+       return tpm2_get_tpm_pt(chip, 0x100, &dummy,
+                              "attempting to generate an interrupt");
 }
 EXPORT_SYMBOL_GPL(tpm2_gen_interrupt);
+
+/**
+ * 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);