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From:   Stefan Mahnke-Hartmann <stefan.mahnke-hartmann@infineon.com>
To:     <jarkko@kernel.org>, <linux-integrity@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
CC:     <Marten.Lindahl@axis.com>, <martenli@axis.com>, <jgg@ziepe.ca>,
        <jsnitsel@redhat.com>, <nayna@linux.vnet.ibm.com>,
        <johannes.holland@infineon.com>, <peterhuewe@gmx.de>,
        Stefan Mahnke-Hartmann <stefan.mahnke-hartmann@infineon.com>
Subject: [PATCH 2/2] tpm: Add Field Upgrade mode support for Infineon TPM2 modules
Date:   Fri, 6 May 2022 14:31:48 +0200
Message-ID: <20220506123145.229058-2-stefan.mahnke-hartmann@infineon.com>
In-Reply-To: <20220506123145.229058-1-stefan.mahnke-hartmann@infineon.com>
References: <20220506123145.229058-1-stefan.mahnke-hartmann@infineon.com>
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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@infineon.com>
---
 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