[PATCH 2/2] tpm: Add Field Upgrade mode support for Infineon TPM2 modules

[Stefan Mahnke-Hartmann]

TPM2_GetCapability with a capability that has the property type value
of TPM_PT_TOTAL_COMMANDS returns a zero length list, when an Infineon
TPM2 is in Field Upgrade mode.
Since an Infineon TPM2.0 in Field Upgrade mode returns RC_SUCCESS on
TPM2_Startup, the Field Upgrade mode has to be detected by
TPM2_GetCapability.

Signed-off-by: Stefan Mahnke-Hartmann <stefan.mahnke-hartmann@xxxxxxxxxxxx>
---
 drivers/char/tpm/tpm2-cmd.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index e62a644ce26b..659130e2936e 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -746,6 +746,12 @@ int tpm2_auto_startup(struct tpm_chip *chip)
 	}
 
 	rc = tpm2_get_cc_attrs_tbl(chip);
+	/*
+	 * Infineon TPM in Field Upgrade mode will return no data for the number
+	 * of supported commands.
+	 */
+	if (rc == -ENODATA)
+		rc = TPM2_RC_UPGRADE;
 
 out:
 	if (rc == TPM2_RC_UPGRADE) {
-- 
2.25.1