[PATCH v18 3/6] tpm: Handle an exception for TPM Firmware Update mode.

[amirmizi6]

From: Amir Mizinski <amirmizi6@xxxxxxxxx>

Add a condition to enable communication with the TPM while the TPM is in
firmware update mode.
In such a case if power was cut during the TPM firmware update, the driver
should ignore the "selftest" command return code (TPM2_RC_UPGRADE or
TPM2_RC_COMMAND_CODE) and skip the rest of the TPM initialization
sequence.

Suggested-by: Benoit Houyere <benoit.houyere@xxxxxx>
Signed-off-by: Amir Mizinski <amirmizi6@xxxxxxxxx>
---
 drivers/char/tpm/tpm2-cmd.c | 4 ++++
 include/linux/tpm.h         | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index a25815a..c2b541d 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -729,6 +729,10 @@ int tpm2_auto_startup(struct tpm_chip *chip)
 		goto out;
 
 	rc = tpm2_do_selftest(chip);
+
+	if (rc == TPM2_RC_UPGRADE || rc == TPM2_RC_COMMAND_CODE)
+		return 0;
+
 	if (rc && rc != TPM2_RC_INITIALIZE)
 		goto out;
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index aa11fe3..c5bf934 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -207,6 +207,7 @@ enum tpm2_return_codes {
 	TPM2_RC_INITIALIZE	= 0x0100, /* RC_VER1 */
 	TPM2_RC_FAILURE		= 0x0101,
 	TPM2_RC_DISABLED	= 0x0120,
+	TPM2_RC_UPGRADE         = 0x012D,
 	TPM2_RC_COMMAND_CODE    = 0x0143,
 	TPM2_RC_TESTING		= 0x090A, /* RC_WARN */
 	TPM2_RC_REFERENCE_H0	= 0x0910,
-- 
2.7.4