[PATCH v3 4/4] tpm_tis: Resend command to recover from data transfer errors

[Alexander Steffen]

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@xxxxxxxxxxxx>
---
 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 a6d1396413a7..7b13ad4bd6dd 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -532,10 +532,17 @@ 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;
+	}
 
 	/* go and do it */
 	rc = tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_GO);
-- 
2.25.1