From: Alexander Steffen <Alexander.Steffen@infineon.com>
Date: Tue, 13 Jun 2023 18:02:59 +0000 (+0200)
Subject: tpm_tis: Resend command to recover from data transfer errors
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=280db21e153d8810ce3b93640c63ae922bcb9e8e;p=linux.git

tpm_tis: Resend command to recover from data transfer errors

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>
---

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 52e2dc7a9f818..1b350412d8a6b 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -539,10 +539,17 @@ 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);