From 280db21e153d8810ce3b93640c63ae922bcb9e8e Mon Sep 17 00:00:00 2001
From: Alexander Steffen <Alexander.Steffen@infineon.com>
Date: Tue, 13 Jun 2023 20:02:59 +0200
Subject: [PATCH] tpm_tis: Resend command to recover from data transfer errors
Git-commit: 280db21e153d8810ce3b93640c63ae922bcb9e8e
Patch-mainline: v6.6-rc1
References: git-fixes

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/char/tpm/tpm_tis_core.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

--- 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_
 	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) {