[PATCH AUTOSEL 6.4 25/41] tpm_tis: Resend command to recover from data transfer errors

Sasha Levin
2023-09-08T18:20:36Z

From: Alexander Steffen <Alexander.Steffen@infineon.com>

[ Upstream commit 280db21e153d8810ce3b93640c63ae922bcb9e8e ]

Similar to the transmission of TPM responses, also the transmission of TPM
commands may become corrupted. Instead of aborting when detecting such
issues, try resending the command again.

Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/char/tpm/tpm_tis_core.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index b95963095729a..f4c4c027b062d 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -512,10 +512,17 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
int rc;
u32 ordinal;
unsigned long dur;
+ unsigned int try;

- rc = tpm_tis_send_data(chip, buf, len);
- if (rc < 0)
- return rc;
+ for (try = 0; try < TPM_RETRY; try++) {
+ rc = tpm_tis_send_data(chip, buf, len);
+ if (rc >= 0)
+ /* Data transfer done successfully */
+ break;
+ else if (rc != -EIO)
+ /* Data transfer failed, not recoverable */
+ return rc;
+ }

rc = tpm_tis_verify_crc(priv, len, buf);
if (rc < 0) {
--
2.40.1